ORCID Profile
0000-0002-9516-1581
Current Organisation
University of Adelaide
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Astronomical and Space Sciences | Galactic Astronomy | Astronomical and Space Instrumentation | Cosmology and Extragalactic Astronomy | High Energy Astrophysics; Cosmic Rays | Astrobiology | Cosmic Ray Physics | Astronomy And Astrophysics | Instruments And Techniques
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Technology | Physical sciences | Education and Training Systems not elsewhere classified | Education and Training not elsewhere classified |
Related Links
Publications
Discovery of hard-spectrumγ-ray emission from the BL Lacertae object 1ES 0414+009
Publisher: EDP Sciences
Date: 02-2012
Diffuse Galactic gamma-ray emission with H.E.S.S.
Publisher: American Physical Society (APS)
Date: 30-12-2014
Status of the ROTSE-III telescope network
Publisher: Wiley
Date: 09-2006
Exploring Broadband GRB Behavior during γ‐Ray Emission
Publisher: American Astronomical Society
Date: 10-03-2007
DOI: 10.1086/510896
Multi-wavelength observations of H 2356–309
Publisher: EDP Sciences
Date: 06-2010
DISCOVERY OF THE HARD SPECTRUM VHE γ-RAY SOURCE HESS J1641–463
Publisher: American Astronomical Society
Date: 22-09-2014
TeV -ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with H.E.S.S.
Publisher: Oxford University Press (OUP)
Date: 02-05-2014
DOI: 10.1093/MNRAS/STU459
HESS J1818–154, a new composite supernova remnant discovered in TeV gamma rays and X-rays
Publisher: EDP Sciences
Date: 02-2014
The unidentified TeV source (TeV J2032+4130) and surrounding field: Final HEGRA IACT-System results
Publisher: EDP Sciences
Date: 02-2005
Discovery of Molecular and Atomic Clouds Associated with the Magellanic Superbubble 30 Doradus C
Publisher: American Astronomical Society
Date: 03-07-2017
Analysis of the optical-depth-corrected molecular line and diffuse TeV gamma-ray correlation in the Galactic centre
Publisher: AIP
Date: 2012
DOI: 10.1063/1.4772298
HESS and Fermi-LAT discovery of γ-rays from the blazar 1ES 1312−423
Publisher: Oxford University Press (OUP)
Date: 08-2013
ALMA CO Observations of the Mixed-morphology Supernova Remnant W49B: Efficient Production of Recombining Plasma and Hadronic Gamma Rays via Shock–Cloud Interactions
Publisher: American Astronomical Society
Date: 10-2021
Long-term monitoring of PKS 2155−304 with ATOM and H.E.S.S.: investigation of optical/γ-ray correlations in different spectral states
Publisher: EDP Sciences
Date: 11-2014
H.E.S.S. discovery of VHEγ-rays from the quasar PKS 1510−089
Publisher: EDP Sciences
Date: 06-2013
ALMA Observations of Supernova Remnant N49 in the LMC. I. Discovery of CO Clumps Associated with X-Ray and Radio Continuum Shells
Publisher: American Astronomical Society
Date: 09-08-2018
Mopra Central Molecular Zone Carbon Monoxide Survey Status
Publisher: Cambridge University Press (CUP)
Date: 07-2016
DOI: 10.1017/S1743921316012035
Abstract: We present an update on the Mopra Central Molecular Zone Carbon Monoxide (CO) survey, with data taken in 2016 extending the original 3.5° ≥ l ≥ 358.5°, +1.0° ≥ b ≥ -0.5° to 4.0° ≥ l ≥ 358.0°, +1.0° ≥ b ≥ -1.0°. Using the four simultaneously observed lines of 12 CO, 13 CO, C 18 O, and C 17 O Nyquist s led at 0.6′ spatial and 0.1 km/s spectral resolution, we are building an optical-thickness-corrected three-dimensional model of the diffuse gas, and making cloud mass estimates. This data, as part of the Mopra Southern Galactic Plane CO Survey (Braiding et al . (2015), Burton et al . (2013)), is at the highest resolution available across such a widespread region, and includes the Sagittarius A, Sagittarius B2, Sagittarius C, and G1.3 cloud complexes, as well as Bania’s Clump 2.
An unidentified TeV source in the vicinity of Cygnus OB2
Publisher: EDP Sciences
Date: 23-09-2002
EMU Detection of a Large and Low Surface Brightness Galactic SNR G288.8–6.3
Publisher: American Astronomical Society
Date: 07-09-2023
The sensitivity of the CANGAROO I analyses of the Crab and Vela plerions to image selection cuts
Publisher: Elsevier BV
Date: 06-2001
The Anomalous Early Afterglow of GRB 050801
Publisher: American Astronomical Society
Date: 23-01-2006
DOI: 10.1086/501007
Simultaneous multiwavelength observations of the second exceptional γ-ray flare of PKS 2155-304 in July 2006
Publisher: EDP Sciences
Date: 15-06-2009
The ground-based large-area wide-angle γ-ray and cosmic-ray experiment HiSCORE
Publisher: Elsevier BV
Date: 12-2011
Molecular and Atomic Clouds Associated with the Gamma-Ray Supernova Remnant Puppis A
Publisher: American Astronomical Society
Date: 10-2022
Abstract: We have carried out a study of the interstellar medium (ISM) toward the shell-like supernova remnant (SNR) Puppis A using NANTEN CO and ATCA H i data. We synthesized a comprehensive picture of the SNR radiation by combining the ISM data with the gamma-ray and X-ray distributions. The ISM, both atomic and molecular gas, is dense and highly clumpy, and is distributed all around the SNR, but mainly in the northeast. The CO distribution revealed an enhanced line intensity ratio of CO( J = 2–1)/( J = 1–0) transitions as well as CO line broadening, which indicate shock heating/acceleration. The results support the assertion that Puppis A is located at 1.4 kpc, in the Local Arm. The ISM interacting with the SNR has a large mass of ∼10 4 M ⊙ , which is dominated by H i , showing good spatial correspondence with the Fermi-LAT gamma-ray image. This favors a hadronic origin of the gamma-rays, while an additional contribution from a leptonic component is not excluded. The distribution of the X-ray ionization timescales within the shell suggests that the shock front ionized various parts of the ISM at epochs ranging over a few to ten thousand years. We therefore suggest that the age of the SNR is around 10 4 yr as given by the largest ionization timescale. We estimate the total cosmic-ray energy W p to be 10 47 erg, which is well placed in the cosmic-ray escaping phase of an age– W p plot including more than ten SNRs.
Discovery of VHEγ-rays from the BL Lacertae object PKS 0548–322
Publisher: EDP Sciences
Date: 10-2010
Discovery of VHEγ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9 − 311909
Publisher: EDP Sciences
Date: 06-2012
Discovery of Shocked Molecular Clouds Associated with the Shell-type Supernova Remnant RX J0046.5−7308 in the Small Magellanic Cloud
Publisher: American Astronomical Society
Date: 14-08-2019
Measurement of the EBL spectral energy distribution using the VHE γ-ray spectra of H.E.S.S. blazars
Publisher: EDP Sciences
Date: 10-2017
DOI: 10.1051/0004-6361/201731200
Abstract: Very high-energy γ rays (VHE, E ≳ 100 GeV) propagating over cosmological distances can interact with the low-energy photons of the extragalactic background light (EBL) and produce electron-positron pairs. The transparency of the Universe to VHE γ rays is then directly related to the spectral energy distribution (SED) of the EBL. The observation of features in the VHE energy spectra of extragalactic sources allows the EBL to be measured, which otherwise is very difficult. An EBL model-independent measurement of the EBL SED with the H.E.S.S. array of Cherenkov telescopes is presented. It was obtained by extracting the EBL absorption signal from the reanalysis of high-quality spectra of blazars. From H.E.S.S. data alone the EBL signature is detected at a significance of 9.5 σ , and the intensity of the EBL obtained in different spectral bands is presented together with the associated γ -ray horizon.
Search for continuous gravitational waves from HESS J1427-608 with a hidden Markov model
Publisher: American Physical Society (APS)
Date: 15-11-2022
H.E.S.S. reveals a lack of TeV emission from the supernova remnant Puppis A
Publisher: EDP Sciences
Date: 27-02-2015
Radio emission from interstellar shocks: Young type Ia supernova remnants and the case of N 103B in the Large Magellanic Cloud
Publisher: Springer Science and Business Media LLC
Date: 11-2019
The H.E.S.S. Galactic plane survey
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201732098
Abstract: We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) γ -rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the discovery of 16 new sources of VHE γ -rays. The High Energy Spectroscopic System (H.E.S.S.) Galactic plane survey (HGPS) was a decade-long observation program carried out by the H.E.S.S. I array of Cherenkov telescopes in Namibia from 2004 to 2013. The observations amount to nearly 2700 h of quality-selected data, covering the Galactic plane at longitudes from ℓ = 250° to 65° and latitudes | b |≤ 3°. In addition to the unprecedented spatial coverage, the HGPS also features a relatively high angular resolution (0.08° ≈ 5 arcmin mean point spread function 68% containment radius), sensitivity (≲1.5% Crab flux for point-like sources), and energy range (0.2–100 TeV). We constructed a catalog of VHE γ -ray sources from the HGPS data set with a systematic procedure for both source detection and characterization of morphology and spectrum. We present this likelihood-based method in detail, including the introduction of a model component to account for unresolved, large-scale emission along the Galactic plane. In total, the resulting HGPS catalog contains 78 VHE sources, of which 14 are not reanalyzed here, for ex le, due to their complex morphology, namely shell-like sources and the Galactic center region. Where possible, we provide a firm identification of the VHE source or plausible associations with sources in other astronomical catalogs. We also studied the characteristics of the VHE sources with source parameter distributions. 16 new sources were previously unknown or unpublished, and we in idually discuss their identifications or possible associations. We firmly identified 31 sources as pulsar wind nebulae (PWNe), supernova remnants (SNRs), composite SNRs, or gamma-ray binaries. Among the 47 sources not yet identified, most of them (36) have possible associations with cataloged objects, notably PWNe and energetic pulsars that could power VHE PWNe.
Discovery of fast variability of the TeV γ-ray flux from the giant radio galaxy M87 with H.E.S.S.
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2757288
The Tunka – Multi-component EAS detector for high energy cosmic ray studies
Publisher: Elsevier BV
Date: 12-2013
XMM-Newton observations of the first unidentified TeV gamma-ray source TeV J2032+4130
Publisher: EDP Sciences
Date: 02-05-2007
Systematic search for very-high-energy gamma-ray emission from bow shocks of runaway stars
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201630151
Abstract: Context. Runaway stars form bow shocks by ploughing through the interstellar medium at supersonic speeds and are promising sources of non-thermal emission of photons. One of these objects has been found to emit non-thermal radiation in the radio band. This triggered the development of theoretical models predicting non-thermal photons from radio up to very-high-energy (VHE, E ≥ 0.1 TeV) gamma rays. Subsequently, one bow shock was also detected in X-ray observations. However, the data did not allow discrimination between a hot thermal and a non-thermal origin. Further observations of different candidates at X-ray energies showed no evidence for emission at the position of the bow shocks either. A systematic search in the Fermi -LAT energy regime resulted in flux upper limits for 27 candidates listed in the E-BOSS catalogue. Aim. Here we perform the first systematic search for VHE gamma-ray emission from bow shocks of runaway stars. Methods. Using all available archival H.E.S.S. data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue release. Out of the 73 bow shock candidates in this catalogue, 32 have been observed with H.E.S.S. Results. None of the observed 32 bow shock candidates in this population study show significant emission in the H.E.S.S. energy range. Therefore, flux upper limits are calculated in five energy bins and the fraction of the kinetic wind power that is converted into VHE gamma rays is constrained. Conclusions. Emission from stellar bow shocks is not detected in the energy range between 0.14 and 18 TeV.The resulting upper limits constrain the level of VHE gamma-ray emission from these objects down to 0.1–1% of the kinetic wind energy.
Very high energy gamma-ray observations of the galaxy clusters Abell 496 and Abell 85 with HESS
Publisher: EDP Sciences
Date: 22-12-2008
3 to 12 millimetre studies of dense gas towards the western rim of supernova remnant RX J1713.7−3946
Publisher: Oxford University Press (OUP)
Date: 19-03-2012
Localizing the VHE γ-ray source at the Galactic Centre
Publisher: Oxford University Press (OUP)
Date: 03-2010
Probing the local environment of the supernova remnant HESS J1731−347 with CO and CS observations
Publisher: Oxford University Press (OUP)
Date: 11-2017
Discovery of the source HESS J1356-645 associated with the young and energetic PSR J1357-6429
Publisher: EDP Sciences
Date: 09-2011
Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S.
Publisher: EDP Sciences
Date: 21-10-2009
H.E.S.S. OBSERVATIONS OF THE GLOBULAR CLUSTERS NGC 6388 AND M15 AND SEARCH FOR A DARK MATTER SIGNAL
Publisher: American Astronomical Society
Date: 08-06-2011
A new template background estimate for source searching in TeV γ-ray astronomy
Publisher: EDP Sciences
Date: 10-2003
Molecular Clouds Associated with the Type Ia SNR N103B in the Large Magellanic Cloud
Publisher: American Astronomical Society
Date: 25-10-2018
Prompt optical observations of GRB 080330 and GRB 080413A
Publisher: AIP
Date: 2008
DOI: 10.1063/1.3027891
HESS upper limit on the very high energy γ-ray emission from the globular cluster 47 Tucanae
Publisher: EDP Sciences
Date: 25-03-2009
Searching for an interstellar medium association for HESS J1534 − 571
Publisher: Oxford University Press (OUP)
Date: 06-07-2018
The starburst galaxy NGC 253 revisited by H.E.S.S. and Fermi-LAT
Publisher: EDP Sciences
Date: 09-2018
DOI: 10.1051/0004-6361/201833202
Abstract: Context. NGC 253 is one of only two starburst galaxies found to emit γ -rays from hundreds of MeV to multi-TeV energies. Accurate measurements of the very-high-energy (VHE E 100 GeV) and high-energy (HE E 60 MeV) spectra are crucial to study the underlying particle accelerators, probe the dominant emission mechanism(s) and to study cosmic-ray interaction and transport. Aims. The measurement of the VHE γ -ray emission of NGC 253 published in 2012 by H.E.S.S. was limited by large systematic uncertainties. Here, the most up to date measurement of the γ -ray spectrum of NGC 253 is investigated in both HE and VHE γ -rays. Assuming a hadronic origin of the γ -ray emission, the measurement uncertainties are propagated into the interpretation of the accelerated particle population. Methods. The data of H.E.S.S. observations are reanalysed using an updated calibration and analysis chain. The improved Fermi –LAT analysis employs more than 8 yr of data processed using pass 8. The cosmic-ray particle population is evaluated from the combined HE–VHE γ -ray spectrum using NAIMA in the optically thin case. Results. The VHE γ -ray energy spectrum is best fit by a power-law distribution with a flux normalisation of (1.34 ± 0.14 stat ± 0.27 sys ) × 10 −13 cm −2 s −1 TeV 1 at 1 TeV – about 40% above, but compatible with the value obtained in Abramowski et al. (2012). The spectral index Γ = 2.39 ± 0.14 stat ± 0.25 sys is slightly softer than but consistent with the previous measurement within systematic errors. In the Fermi energy range an integral flux of F ( E 60 MeV) = (1.56 ± 0.28 stat ± 0.15 sys ) × 10 −8 cm −2 s −1 is obtained. At energies above ∼3 GeV the HE spectrum is consistent with a power-law ranging into the VHE part of the spectrum measured by H.E.S.S. with an overall spectral index Γ = 2.22 ± 0.06 stat . Conclusions. Two scenarios for the starburst nucleus are tested, in which the gas in the starburst nucleus acts as either a thin or a thick target for hadronic cosmic rays accelerated by the in idual sources in the nucleus. In these two models, the level to which NGC 253 acts as a calorimeter is estimated to a range of f cal = 0.1 to 1 while accounting for the measurement uncertainties. The presented spectrum is likely to remain the most accurate measurements until the Cherenkov Telescope Array (CTA) has collected a substantial set of data towards NGC 253.
Spectrum and variability of the Galactic center VHE γ-ray source HESS J1745-290
Publisher: EDP Sciences
Date: 02-07-2009
The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201527843
Abstract: The supernova remnant (SNR) W49B originated from a core-collapse supernova that occurred between one and four thousand years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (MC). Gamma-ray observations of SNR-MC associations are a powerful tool to constrain the origin of Galactic cosmic rays, as they can probe the acceleration of hadrons through their interaction with the surrounding medium and subsequent emission of non-thermal photons. We report the detection of a γ -ray source coincident with W49B at very high energies (VHE E 100 GeV) with the H.E.S.S. Cherenkov telescopes together with a study of the source with five years of Fermi -LAT high-energy γ -ray (0.06–300 GeV) data. The smoothly connected, combined source spectrum, measured from 60 MeV to multi-TeV energies, shows two significant spectral breaks at 304 ± 20 MeV and 8.4 −2.5 +2.2 GeV the latter is constrained by the joint fit from the two instruments. The detected spectral features are similar to those observed in several other SNR-MC associations and are found to be indicative of γ -ray emission produced through neutral-pion decay.
H.E.S.S. Follow-up Observations of Binary Black Hole Coalescence Events during the Second and Third Gravitational-wave Observing Runs of Advanced LIGO and Advanced Virgo
Publisher: American Astronomical Society
Date: 12-2021
Abstract: We report on the observations of four well-localized binary black hole (BBH) mergers by the High Energy Stereoscopic System (H.E.S.S.) during the second and third observing runs of Advanced LIGO and Advanced Virgo, O2 and O3. H.E.S.S. can observe 20 deg 2 of the sky at a time and follows up gravitational-wave (GW) events by “tiling” localization regions to maximize the covered localization probability. During O2 and O3, H.E.S.S. observed large portions of the localization regions, between 35% and 75%, for four BBH mergers (GW170814, GW190512_180714, GW190728_064510, and S200224ca). For these four GW events, we find no significant signal from a pointlike source in any of the observations, and we set upper limits on the very high energy ( GeV) γ -ray emission. The 1–10 TeV isotropic luminosity of these GW events is below 10 45 erg s −1 at the times of the H.E.S.S. observations, around the level of the low-luminosity GRB 190829A. Assuming no changes are made to how follow-up observations are conducted, H.E.S.S. can expect to observe over 60 GW events per year in the fourth GW observing run, O4, of which eight would be observable with minimal latency.
THE 2012 FLARE OF PG 1553+113 SEEN WITH H.E.S.S. ANDFERMI-LAT
Publisher: American Astronomical Society
Date: 24-03-2015
Interstellar gas towards the TeV γ-ray sources HESS J1640−465 and HESS J1641−463
Publisher: Oxford University Press (OUP)
Date: 19-10-2016
The population of TeV pulsar wind nebulae in the H.E.S.S. Galactic Plane Survey
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201629377
Abstract: The nine-year H.E.S.S. Galactic Plane Survey (HGPS) has yielded the most uniform observation scan of the inner Milky Way in the TeV gamma-ray band to date. The sky maps and source catalogue of the HGPS allow for a systematic study of the population of TeV pulsar wind nebulae found throughout the last decade. To investigate the nature and evolution of pulsar wind nebulae, for the first time we also present several upper limits for regions around pulsars without a detected TeV wind nebula. Our data exhibit a correlation of TeV surface brightness with pulsar spin-down power Ė . This seems to be caused both by an increase of extension with decreasing Ė , and hence with time, compatible with a power law R PWN ( Ė ) ~ Ė −0.65±0.20 , and by a mild decrease of TeV gamma-ray luminosity with decreasing Ė , compatible with L 1−10 TeV ~ Ė 0.59±0.21 . We also find that the offsets of pulsars with respect to the wind nebula centre with ages around 10 kyr are frequently larger than can be plausibly explained by pulsar proper motion and could be due to an asymmetric environment. In the present data, it seems that a large pulsar offset is correlated with a high apparent TeV efficiency L 1−10 TeV ∕ Ė . In addition to 14 HGPS sources considered firmly identified pulsar wind nebulae and 5 additional pulsar wind nebulae taken from literature, we find 10 HGPS sources that are likely TeV pulsar wind nebula candidates. Using a model that subsumes the present common understanding of the very high-energy radiative evolution of pulsar wind nebulae, we find that the trends and variations of the TeV observables and limits can be reproduced to a good level, drawing a consistent picture of present-day TeV data and theory.
A multi-wavelength study of the unidentified TeV gamma-ray source HESS J1626−490
Publisher: EDP Sciences
Date: 24-12-2010
Towards a three-dimensional distribution of the molecular clouds in the Galactic Centre
Publisher: Oxford University Press (OUP)
Date: 13-07-2017
The Mopra Southern galactic plane CO survey-Data release 3
Publisher: Cambridge University Press (CUP)
Date: 2018
DOI: 10.1017/PASA.2018.18
Abstract: We present observations of 50 deg 2 of the Mopra carbon monoxide (CO) survey of the Southern Galactic Plane, covering Galactic longitudes l = 300–350° and latitudes | b | ⩽ 0.5°. These data have been taken at 0.6 arcmin spatial resolution and 0.1 km s −1 spectral resolution, providing an unprecedented view of the molecular clouds and gas of the Southern Galactic Plane in the 109–115 GHz J = 1–0 transitions of 12 CO, 13 CO, C 18 O, and C 17 O. We present a series of velocity-integrated maps, spectra, and position-velocity plots that illustrate Galactic arm structures and trace masses on the order of ~10 6 M ⊙ deg −2 , and include a preliminary catalogue of C 18 O clumps located between l = 330–340°. Together with the information about the noise statistics of the survey, these data can be retrieved from the Mopra CO website and the PASA data store.
THE CARBON INVENTORY IN A QUIESCENT, FILAMENTARY MOLECULAR CLOUD IN G328
Publisher: American Astronomical Society
Date: 29-01-2014
H.E.S.S. constraints on dark matter annihilations towards the sculptor and carina dwarf galaxies
Publisher: Elsevier BV
Date: 03-2011
Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S.
Publisher: American Physical Society (APS)
Date: 22-01-2013
First ground-based measurement of sub-20 GeV to 100 GeV γ-Rays from the Vela pulsar with H.E.S.S. II
Publisher: EDP Sciences
Date: 12-2018
DOI: 10.1051/0004-6361/201732153
Abstract: Aims. We report on the measurement and investigation of pulsed high-energy γ -ray emission from the Vela pulsar, PSR B0833−45, based on observations with the largest telescope of H.E.S.S., CT5, in monoscopic mode, and on data obtained with the Fermi -LAT. Methods. Data from 40.3 h of observations carried out with the H.E.S.S. II array from 2013 to 2015 have been used. A dedicated very low-threshold event reconstruction and analysis pipeline was developed to achieve the lowest possible energy threshold. Eight years of Fermi -LAT data were analysed and also used as reference to validate the CT5 telescope response model and analysis methods. Results. A pulsed γ -ray signal at a significance level of more than 15 σ is detected from the P2 peak of the Vela pulsar light curve. Of a total of 15 835 events, more than 6000 lie at an energy below 20 GeV, implying a significant overlap between H.E.S.S. II-CT5 and the Fermi -LAT. While the investigation of the pulsar light curve with the LAT confirms characteristics previously known up to 20 GeV in the tens of GeV energy range, CT5 data show a change in the pulse morphology of P2, i.e. an extreme sharpening of its trailing edge, together with the possible onset of a new component at 3.4 σ significance level. Assuming a power-law model for the P2 spectrum, an excellent agreement is found for the photon indices (Γ ≃ 4.1) obtained with the two telescopes above 10 GeV and an upper bound of 8% is derived on the relative offset between their energy scales. Using data from both instruments, it is shown however that the spectrum of P2 in the 10–100 GeV has a pronounced curvature this is a confirmation of the sub-exponential cut-off form found at lower energies with the LAT. This is further supported by weak evidence of an emission above 100 GeV obtained with CT5. In contrast, converging indications are found from both CT5 and LAT data for the emergence of a hard component above 50 GeV in the leading wing (LW2) of P2, which possibly extends beyond 100 GeV. Conclusions. The detection demonstrates the performance and understanding of CT5 from 100 GeV down to the sub-20 GeV domain, i.e. unprecedented low energy for ground-based γ -ray astronomy. The extreme sharpening of the trailing edge of the P2 peak found in the H.E.S.S. II light curve of the Vela pulsar and the possible extension beyond 100 GeV of at least one of its features, LW2, provide further constraints to models of γ -Ray emission from pulsars.
Discovery of TeVγ-ray emission from PKS 0447-439 and derivation of an upper limit on its redshift
Publisher: EDP Sciences
Date: 04-2013
ALMA CO Observations of Gamma-Ray Supernova Remnant N132D in the Large Magellanic Cloud: Possible Evidence for Shocked Molecular Clouds Illuminated by Cosmic-Ray Protons
Publisher: American Astronomical Society
Date: 12-10-2020
XMM-Newton observations of HESS J1813-178 reveal a composite Supernova remnant
Publisher: EDP Sciences
Date: 16-05-2007
ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-ionized and Photoionized Nebulae
Publisher: American Astronomical Society
Date: 03-2019
Revisiting the Westerlund 2 field with the HESS telescope array
Publisher: EDP Sciences
Date: 30-11-2010
Detailed spectral and morphological analysis of the shell type supernova remnant RCW 86
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201526545
Abstract: Aim. We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW 86 and for insights into the production mechanism leading to the RCW 86 very high-energy γ -ray emission. Methods. We analyzed High Energy Spectroscopic System (H.E.S.S.) data that had increased sensitivity compared to the observations presented in the RCW 86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5–1 keV X-ray band, the 2–5 keV X-ray band, radio, and γ -ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models. Results. We present the first conclusive evidence that the TeV γ -ray emission region is shell-like based on our morphological studies. The comparison with 2–5 keV X-ray data reveals a correlation with the 0.4–50 TeV γ -ray emission. The spectrum of RCW 86 is best described by a power law with an exponential cutoff at E cut = (3.5 ± 1.2 stat ) TeV and a spectral index of Γ ≈ 1.6 ± 0.2. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW 86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to ~0.1% of the initial kinetic energy of a Type Ia supernova explosion (10 51 erg). When using a hadronic model, a magnetic field of B ≈ 100 μ G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E −2 spectrum for the proton distribution cannot describe the γ -ray data. Instead, a spectral index of Γ p ≈ 1.7 would be required, which implies that ∼7 × 10 49 / n cm −3 has been transferred into high-energy protons with the effective density n cm −3 = n /1 cm −3 . This is about 10% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1 cm −3 .
Dense molecular gas at 12 mm towards Galactic TeV gamma-ray sources
Publisher: Oxford University Press (OUP)
Date: 17-02-2017
DOI: 10.1093/MNRAS/STX369
The GCT camera for the Cherenkov Telescope Array
Publisher: SPIE
Date: 27-07-2016
DOI: 10.1117/12.2231685
Discovery of variable VHEγ-ray emission from the binary system 1FGL J1018.6–5856
Publisher: EDP Sciences
Date: 05-2015
A Study of the Interstellar Medium Towards the Unidentified Dark TeV γ-Ray Sources HESS J1614–518 and HESS J1616–508
Publisher: Cambridge University Press (CUP)
Date: 2017
DOI: 10.1017/PASA.2017.59
Abstract: HESS J1614–518 and HESS J1616–508 are two tera-electron volt γ-ray sources that are not firmly associated with any known counterparts at other wavelengths. We investigate the distribution of interstellar medium towards the tera-electron volt γ-ray sources using results from a 7-mm-wavelength Mopra study, the Mopra Southern Galactic Plane CO Survey, the Millimetre Astronomer’s Legacy Team-45 GHz survey and [C i ] data from the HEAT telescope. Data in the CO(1–0) transition lines reveal diffuse gas overlapping the two tera-electron volt sources at several velocities along the line of sight, while observations in the CS(1–0) transition line reveal several interesting dense gas features. To account for the diffuse atomic gas, archival H i data was taken from the Southern Galactic Plane Survey. The observations reveal gas components with masses ~10 3 to 10 5 M ⊙ and with densities ~10 2 to 10 3 cm −3 overlapping the two tera-electron volt sources. Several origin scenarios potentially associated with the tera-electron volt γ-ray sources are discussed in light of the distribution of the local interstellar medium. We find no strong convincing evidence linking any counterpart with HESS J1614–518 or HESS J1616–508.
Very high energy γ-ray observations of the binary PSR B1259-63/SS2883 around the 2007 Periastron
Publisher: EDP Sciences
Date: 03-09-2009
Constraints on the gamma-ray emission from the cluster-scale AGN outburst in the Hydra A galaxy cluster
Publisher: EDP Sciences
Date: 09-2012
Operating performance of the gamma-ray Cherenkov telescope: An end-to-end Schwarzschild–Couder telescope prototype for the Cherenkov Telescope Array
Publisher: Elsevier BV
Date: 02-2017
Discovery of Molecular and Atomic Clouds Associated with the Gamma-Ray Supernova Remnant Kesteven 79
Publisher: American Astronomical Society
Date: 12-09-2018
Interstellar gas toward the Magellanic supernova remnants
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968942
Interstellar gas towards CTB 37A and the TeV gamma-ray source HESS J1714-385
Publisher: Oxford University Press (OUP)
Date: 26-07-2013
A Supernova Remnant Counterpart for HESS J1832−085
Publisher: American Astronomical Society
Date: 07-11-2019
Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622
Publisher: EDP Sciences
Date: 30-11-2010
TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S.
Publisher: American Astronomical Society
Date: 22-11-2017
Discovery of high and very high-energy emission from the BL Lacertae object SHBL J001355.9–185406
Publisher: EDP Sciences
Date: 06-2013
Searches for gamma-ray lines and ‘pure WIMP’ spectra from Dark Matter annihilations in dwarf galaxies with H.E.S.S.
Publisher: IOP Publishing
Date: 23-11-2018
Deeper H.E.S.S. observations of Vela Junior (RX J0852.0−4622): Morphology studies and resolved spectroscopy
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201630002
Abstract: Aims. We study γ -ray emission from the shell-type supernova remnant (SNR) RX J0852.0−4622 to better characterize its spectral properties and its distribution over the SNR. Methods. The analysis of an extended High Energy Spectroscopic System (H.E.S.S.) data set at very high energies ( E 100 GeV) permits detailed studies, as well as spatially resolved spectroscopy, of the morphology and spectrum of the whole RX J0852.0−4622 region. The H.E.S.S. data are combined with archival data from other wavebands and interpreted in the framework of leptonic and hadronic models. The joint Fermi -LAT-H.E.S.S. spectrum allows the direct determination of the spectral characteristics of the parent particle population in leptonic and hadronic scenarios using only GeV-TeV data. Results. An updated analysis of the H.E.S.S. data shows that the spectrum of the entire SNR connects smoothly to the high-energy spectrum measured by Fermi -LAT. The increased data set makes it possible to demonstrate that the H.E.S.S. spectrum deviates significantly from a power law and is well described by both a curved power law and a power law with an exponential cutoff at an energy of E cut = (6.7 ± 1.2 stat ± 1.2 syst ) TeV. The joint Fermi -LAT-H.E.S.S. spectrum allows the unambiguous identification of the spectral shape as a power law with an exponential cutoff. No significant evidence is found for a variation of the spectral parameters across the SNR, suggesting similar conditions of particle acceleration across the remnant. A simple modeling using one particle population to model the SNR emission demonstrates that both leptonic and hadronic emission scenarios remain plausible. It is also shown that at least a part of the shell emission is likely due to the presence of a pulsar wind nebula around PSR J0855−4644.
Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-07-2018
Abstract: Previous detections of in idual astrophysical sources of neutrinos are limited to the Sun and the supernova 1987A, whereas the origins of the diffuse flux of high-energy cosmic neutrinos remain unidentified. On 22 September 2017, we detected a high-energy neutrino, IceCube-170922A, with an energy of ~290 tera-electron volts. Its arrival direction was consistent with the location of a known γ-ray blazar, TXS 0506+056, observed to be in a flaring state. An extensive multiwavelength c aign followed, ranging from radio frequencies to γ-rays. These observations characterize the variability and energetics of the blazar and include the detection of TXS 0506+056 in very-high-energy γ-rays. This observation of a neutrino in spatial coincidence with a γ-ray-emitting blazar during an active phase suggests that blazars may be a source of high-energy neutrinos.
The Mopra Southern Galactic Plane CO Survey
Publisher: Cambridge University Press (CUP)
Date: 2013
DOI: 10.1017/PASA.2013.22
Abstract: We present the first results from a new carbon monoxide (CO) survey of the southern Galactic plane being conducted with the Mopra radio telescope in Australia. The 12 CO, 13 CO, and C 18 O J = 1–0 lines are being mapped over the $l = 305^{\\circ }\\text{--} 345^{\\circ }, b = \\pm 0.5^{\\circ }$ portion of the fourth quadrant of the Galaxy, at 35 arcsec spatial and 0.1 km s −1 spectral resolution. The survey is being undertaken with two principal science objectives: (i) to determine where and how molecular clouds are forming in the Galaxy and (ii) to probe the connection between molecular clouds and the ‘missing’ gas inferred from gamma-ray observations. We describe the motivation for the survey, the instrumentation and observing techniques being applied, and the data reduction and analysis methodology. In this paper, we present the data from the first degree surveyed, $l = 323^{\\circ } \\text{--} 324^{\\circ }, b = \\pm 0.5^{\\circ }$ . We compare the data to the previous CO survey of this region and present metrics quantifying the performance being achieved the rms sensitivity per 0.1 km s −1 velocity channel is ~1.5 K for ${\\rm ^{12}CO}$ and ~0.7 K for the other lines. We also present some results from the region surveyed, including line fluxes, column densities, molecular masses, ${\\rm ^{12}CO/^{13}CO}$ line ratios, and ${\\rm ^{12}CO}$ optical depths. We also examine how these quantities vary as a function of distance from the Sun when averaged over the 1 square degree survey area. Approximately 2 × 10 6 M ⊙ of molecular gas is found along the G323 sightline, with an average H 2 number density of $n_{\\text{H}_2} \\sim 1$ cm −3 within the Solar circle. The CO data cubes will be made publicly available as they are published.
The steady-state multi-TeV diffuse γ-ray emission predicted with galprop and prospects for the Cherenkov Telescope Array
Publisher: Oxford University Press (OUP)
Date: 11-11-2022
Abstract: Cosmic rays (CRs) interact with the diffuse gas, radiation, and magnetic fields in the interstellar medium (ISM) to produce electromagnetic emissions that are a significant component of the all-sky flux across a broad wavelength range. The Fermi–Large Area Telescope (LAT) has measured these emissions at GeV γ-ray energies with high statistics. Meanwhile, the high-energy stereoscopic system (H.E.S.S.) telescope array has observed large-scale Galactic diffuse emission in the TeV γ-ray energy range. The emissions observed at GeV and TeV energies are connected by the common origin of the CR particles injected by the sources, but the energy dependence of the mixture from the general ISM (true ‘diffuse’), those emanating from the relatively nearby interstellar space about the sources, and the sources themselves, is not well understood. In this paper, we investigate predictions of the broad-band emissions using the galprop code over a grid of steady-state 3D models that include variations over CR sources, and other ISM target distributions. We compare, in particular, the model predictions in the very-high energy ( VHE ≳100 GeV) γ-ray range with the H.E.S.S. Galactic plane survey (HGPS) after carefully subtracting emission from catalogued γ-ray sources. Accounting for the unresolved source contribution, and the systematic uncertainty of the HGPS, we find that the galprop model predictions agree with lower estimates for the HGPS source-subtracted diffuse flux. We discuss the implications of the modelling results for interpretation of data from the next generation Cherenkov Telescope Array (CTA).
Collimation of the kiloparsec-scale radio jets in NGC 2663
Publisher: Oxford University Press (OUP)
Date: 12-09-2022
Abstract: We present the discovery of highly collimated radio jets spanning a total of 355 kpc around the nearby elliptical galaxy NGC 2663, and the possible first detection of recollimation on kiloparsec scales. The small distance to the galaxy (∼28.5 Mpc) allows us to resolve portions of the jets to examine their structure. We combine multiwavelength data: radio observations by the Murchison Widefield Array (MWA), the Australian Square Kilometre Array Pathfinder (ASKAP) and the Australia Telescope Compact Array (ATCA), and X-ray data from Chandra, Swift, and SRG/eROSITA. We present intensity, rotation measure, polarization, spectral index, and X-ray environment maps. Regions of the southern jet show simultaneous narrowing and brightening, which can be interpreted as a signature of the recollimation of the jet by external, environmental pressure, though it is also consistent with intermittent active galactic nuclei or complex internal jet structure. X-ray data suggest that the environment is extremely poor if the jet is indeed recollimating, the large recollimation scale (40 kpc) is consistent with a slow jet in a low-density environment.
Molecular shocks and the gamma-ray clouds of the W28 supernova remnant
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968938
A 7 mm line survey of the shocked and disrupted molecular gas towards the W28 field TeV gamma-ray sources
Publisher: Oxford University Press (OUP)
Date: 02-11-2011
First limits on the very-high energy gamma-ray afterglow emission of a fast radio burst
Publisher: EDP Sciences
Date: 2017
Preliminary results from a search for TeV γ-ray emission from SN1987A and the surrounding field with H.E.S.S
Publisher: AIP
Date: 2005
DOI: 10.1063/1.1878420
The TeV supernova remnant shell HESS J1731-347 and its surroundings
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968930
Detection of very high energy radiation from HESS J1908+063 confirms the Milagro unidentified source MGRO J1908+06
Publisher: EDP Sciences
Date: 29-04-2009
Discovery of extended VHEγ-ray emission from the vicinity of the young massive stellar cluster Westerlund 1
Publisher: EDP Sciences
Date: 2012
H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354
Publisher: Oxford University Press (OUP)
Date: 20-02-2018
DOI: 10.1093/MNRAS/STY439
A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201527773
Abstract: Context. Microquasars are potential γ -ray emitters. Indications of transient episodes of γ -ray emission were recently reported in at least two systems: Cyg X-1 and Cyg X-3. The identification of additional γ -ray-emitting microquasars is required to better understand how γ -ray emission can be produced in these systems. Aim. Theoretical models have predicted very high-energy (VHE) γ -ray emission from microquasars during periods of transient outburst. Observations reported herein were undertaken with the objective of observing a broadband flaring event in the γ -ray and X-ray bands. Methods. Contemporaneous observations of three microquasars, GRS 1915+105, Circinus X-1, and V4641 Sgr, were obtained using the High Energy Spectroscopic System (H.E.S.S.) telescope array and the Rossi X-ray Timing Explorer (RXTE) satellite. X-ray analyses for each microquasar were performed and VHE γ -ray upper limits from contemporaneous H.E.S.S. observations were derived. Results. No significant γ -ray signal has been detected in any of the three systems. The integral γ -ray photon flux at the observational epochs is constrained to be I ( GeV) 7.3 × 10 −13 cm −2 s −1 , I ( GeV ) 1.2 × 10 −12 cm −2 s −1 , and I ( GeV) 4.5 × 10 −12 cm −2 s −1 for GRS 1915+105, Circinus X-1, and V4641 Sgr, respectively. Conclusions. The γ -ray upper limits obtained using H.E.S.S. are examined in the context of previous Cherenkov telescope observations of microquasars. The effect of intrinsic absorption is modelled for each target and found to have negligible impact on the flux of escaping γ -rays. When combined with the X-ray behaviour observed using RXTE, the derived results indicate that if detectable VHE γ -ray emission from microquasars is commonplace, then it is likely to be highly transient.
Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7-3946
Publisher: American Astronomical Society
Date: 09-05-2017
Galactic PeVatrons and helping to find them: Effects of galactic absorption on the observed spectra of very high energy
Publisher:
American Physical Society (APS)
Date:
31-08-2018
Publisher: American Physical Society (APS)
Date: 31-08-2018
Dense Gas Towards the RX J1713.7–3946 Supernova Remnant
Publisher: Cambridge University Press (CUP)
Date: 2013
DOI: 10.1017/PASA.2013.35
Abstract: We present results from a Mopra 7 mm-wavelength survey that targeted the dense gas-tracing CS(1-0) transition towards the young γ-ray-bright supernova remnant, RX J1713.7–3946 (SNR G 347.3−0.5). In a hadronic γ-ray emission scenario, where cosmic ray (CR) protons interact with gas to produce the observed γ-ray emission, the mass of potential CR target material is an important factor. We summarise newly discovered dense gas components, towards Cores G and L, and Clumps N1, N2, N3, and T1, which have masses of 1 – 10 4 M ⊙ . We argue that these components are not likely to contribute significantly to γ-ray emission in a hadronic γ-ray emission scenario. This would be the case if RX J1713.7–3946 were at either the currently favoured distance of ~1 kpc or an alternate distance (as suggested in some previous studies) of ~6 kpc. This survey also targeted the shock-tracing SiO molecule. Although no SiO emission corresponding to the RX J1713.7–3946 shock was observed, vibrationally excited SiO(1-0) maser emission was discovered towards what may be an evolved star. Observations taken 1 yr apart confirmed a transient nature, since the intensity, line-width, and central velocity of SiO(J = 1-0,v = 1,2) emission varied significantly.
The Dark Side of ROTSE‐III Prompt GRB Observations
Publisher: American Astronomical Society
Date: 10-11-2007
DOI: 10.1086/521668
Detection of GRB 060927 atz= 5.47: Implications for the Use of Gamma‐Ray Bursts as Probes of the End of the Dark Ages
Publisher: American Astronomical Society
Date: 11-2007
DOI: 10.1086/521546
The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes. Part II: mirror alignment and point spread function
Publisher: Elsevier BV
Date: 11-2003
Chandra observations of the HII complex G5.89-0.39 and TeV gamma-ray source HESSJ1800-240B
Publisher: Elsevier BV
Date: 09-2016
Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS2155 −
Publisher:
American Physical Society (APS)
Date:
20-11-2013
Publisher: American Physical Society (APS)
Date: 20-11-2013
HiSCORE: A new detector for astroparticle and particle physics beyond 10 TeV
Publisher: Elsevier BV
Date: 11-2012
Relationship between Intervention Dose and Outcomes in Living Well with Diabetes—A Randomized Trial of a Telephone-Delivered Lifestyle-Based Weight Loss Intervention
Publisher: SAGE Publications
Date: 11-2015
DOI: 10.4278/AJHP.140206-QUAN-62
Abstract: To examine associations of intervention dose with weight, physical activity, glycemic control, and diet outcomes in a randomized trial of a telephone counseling intervention. Study design was a secondary analysis of intervention group. Study setting was primary care practices in a disadvantaged community in Australia. Participants were adult patients with type 2 diabetes (n = 151). Up to 27 telephone counseling calls were made during 18 months. Intervention dose was assessed as the number of calls completed (in tertile categories). Primary outcomes were weight and HbA1c, and moderate to vigorous intensity physical activity via accelerometer. Secondary outcomes were dietary energy intake and diet quality via a validated questionnaire. Analyses employed were bivariate associations of call completion with sociodemographics, and confounder-adjusted linear mixed models for associations of call completion with outcomes (multiple imputation of missing data). Only previous diagnosis of depression/anxiety had a statistically significant (p= .008) association with call completion. Call completion was significantly associated with weight loss (p .001) but not the other outcomes (p .05). Relative to low call completion, mean weight loss (as a percentage of baseline weight) was greater in the high–call completion group by −3.3% (95% confidence interval, −5.0% to −1.5%). Increased dose of intervention was associated with greater weight loss. More needs to be done to retain patients for the duration of weight loss and behavior change interventions, particularly those with diabetes and comorbid depression, who were the most difficult to engage.
DISCOVERY OF VERY HIGH ENERGY γ-RAY EMISSION FROM CENTAURUS A WITH H.E.S.S.
Publisher: American Astronomical Society
Date: 19-03-2009
H.E.S.S. observations of the binary system PSR B1259-63/LS 2883 around the 2010/2011 periastron passage
Publisher: EDP Sciences
Date: 03-2013
Observation of the Monoceros Loop SNR region with the HEGRA system of IACTs
Publisher: EDP Sciences
Date: 26-03-2004
ISM gas studies towards the TeV PWN HESS J1825−137 and northern region
Publisher: Oxford University Press (OUP)
Date: 03-2016
DOI: 10.1093/MNRAS/STW473
Recent Science from Australian Large-Scale Millimetre Mapping Projects: Proceedings from a Swinburne University Workshop
Publisher: Cambridge University Press (CUP)
Date: 2009
DOI: 10.1071/AS08027
Abstract: Since the recent upgrades to the Australia Telescope National Facility (ATNF) Mopra telescope back-end and receiver system, it has risen from an under-subscribed facility to a sought-after instrument with heavy international competition to gain time. Furthermore, the introduction of the on-the-fly mapping capability in 2004 has made this technique one of Mopra's most popular observing modes. In addition, the recent upgrade of the NANTEN millimetre-wavelength telescope to the sub-millimetre NANTEN2 instrument, has provided a complementary, higher-frequency facility to Mopra. A two-day workshop was held at Swinburne University in June 2008 to disseminate the current state of ongoing large-scale mapping projects and associated spin-offs that the telescopes' upgrades have facilitated, and to decide upon future research directions. Here, we provide a summary of the result-oriented talks as a record of the state of Australian-access single-dish millimetre science in 2008.
Ammonia excitation imaging of shocked gas towards the W28 gamma-ray source HESS J1801−233
Publisher: Oxford University Press (OUP)
Date: 14-07-2016
ERRATUM: “SEARCH FOR DARK MATTER ANNIHILATION SIGNALS FROM THE FORNAX GALAXY CLUSTER WITH H.E.S.S.” (2012, ApJ, 750, 123)
Publisher: American Astronomical Society
Date: 13-02-2014
Large zenith angle observations of flares from Mkn 421 in 2004 with H.E.S.S.
Publisher: AIP
Date: 2005
DOI: 10.1063/1.1878447
An Expanding Shell of Neutral Hydrogen Associated with SN 1006: Hints for the Single-degenerate Origin and Faint Hadronic Gamma-Rays
Publisher: American Astronomical Society
Date: 07-2022
Abstract: We report new H i observations of the Type Ia supernova remnant (SNR) SN 1006 using the Australia Telescope Compact Array with an angular resolution of 4 .′ 5 × 1 .′ 4 (∼2 pc at the assumed SNR distance of 2.2 kpc). We find an expanding gas motion in position–velocity diagrams of H i with an expansion velocity of ∼4 km s −1 and a mass of ∼1000 M ⊙ . The spatial extent of the expanding shell is roughly the same as that of SN 1006. We here propose a hypothesis that SN 1006 exploded inside the wind-blown bubble formed by accretion winds from the progenitor system consisting of a white dwarf and a companion star, and then the forward shock has already reached the wind wall. This scenario is consistent with the single-degenerate model. We also derived the total energy of cosmic-ray protons W p to be only ∼1.2–2.0 × 10 47 erg by adopting the averaged interstellar proton density of ∼25 cm −3 . The small value is compatible with the relation between the age and W p of other gamma-ray SNRs with ages below ∼6 kyr. The W p value in SN 1006 will possibly increase up to several 10 49 erg in the next ∼5 kyr via the cosmic-ray diffusion into the H i wind shell.
PKS 2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observations
Publisher: EDP Sciences
Date: 02-2010
ALMA CO Observations of the Gamma-Ray Supernova Remnant RX J1713.7–3946: Discovery of Shocked Molecular Cloudlets and Filaments at 0.01 pc Scales
Publisher: American Astronomical Society
Date: 27-11-2020
Limits on the TeV gamma-ray afterglow of fast radio bursts with H.E.S.S.
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968996
The γ-ray spectrum of the core of Centaurus A as observed with H.E.S.S. and Fermi-LAT
Publisher: EDP Sciences
Date: 11-2018
DOI: 10.1051/0004-6361/201832640
Abstract: Centaurus A (Cen A) is the nearest radio galaxy discovered as a very-high-energy (VHE 100 GeV–100 TeV) γ -ray source by the High Energy Stereoscopic System (H.E.S.S.). It is a faint VHE γ -ray emitter, though its VHE flux exceeds both the extrapolation from early Fermi -LAT observations as well as expectations from a (misaligned) single-zone synchrotron-self Compton (SSC) description. The latter satisfactorily reproduces the emission from Cen A at lower energies up to a few GeV. New observations with H.E.S.S., comparable in exposure time to those previously reported, were performed and eight years of Fermi -LAT data were accumulated to clarify the spectral characteristics of the γ -ray emission from the core of Cen A. The results allow us for the first time to achieve the goal of constructing a representative, contemporaneous γ -ray core spectrum of Cen A over almost five orders of magnitude in energy. Advanced analysis methods, including the template fitting method, allow detection in the VHE range of the core with a statistical significance of 12 σ on the basis of 213 hours of total exposure time. The spectrum in the energy range of 250 GeV–6 TeV is compatible with a power-law function with a photon index Γ = 2.52 ± 0.13 stat ± 0.20 sys . An updated Fermi -LAT analysis provides evidence for spectral hardening by Δ Γ ≃ 0.4 ± 0.1 at γ -ray energies above 2.8 +1.0 −0.6 GeV at a level of 4.0 σ . The fact that the spectrum hardens at GeV energies and extends into the VHE regime disfavour a single-zone SSC interpretation for the overall spectral energy distribution (SED) of the core and is suggestive of a new γ -ray emitting component connecting the high-energy emission above the break energy to the one observed at VHE energies. The absence of significant variability at both GeV and TeV energies does not yet allow disentanglement of the physical nature of this component, though a jet-related origin is possible and a simple two-zone SED model fit is provided to this end.
Search for extendedγ-ray emission around AGN with H.E.S.S. andFermi-LAT
Publisher: EDP Sciences
Date: 02-2014
Constraints on the Intergalactic Magnetic Field Using Fermi-LAT and H.E.S.S. Blazar Observations
Publisher: American Astronomical Society
Date: 06-2023
Abstract: Magnetic fields in galaxies and galaxy clusters are believed to be the result of the lification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron−positron pairs, which can subsequently initiate electromagnetic cascades. The gamma-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of B 7.1 × 10 −16 G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of 10 4 (10 7 ) yr, IGMF strengths below 1.8 × 10 −14 G (3.9 × 10 −14 G) are excluded, which rules out specific models for IGMF generation in the early universe.
The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes. Part I: layout and components of the system
Publisher: Elsevier BV
Date: 11-2003
TeV gamma-ray observations of SS-433 and a survey of the surrounding field with the HEGRA IACT-System
Publisher: EDP Sciences
Date: 29-07-2005
HEGRA discovery of the first unidentified TeV source
Publisher: Elsevier BV
Date: 04-2004
Population study of Galactic supernova remnants at very high γ-ray energies with H.E.S.S.
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201732125
Abstract: Shell-type supernova remnants (SNRs) are considered prime candidates for the acceleration of Galactic cosmic rays (CRs) up to the knee of the CR spectrum at E ≈ 3 × 10 15 eV. Our Milky Way galaxy hosts more than 350 SNRs discovered at radio wavelengths and at high energies, of which 220 fall into the H.E.S.S. Galactic Plane Survey (HGPS) region. Of those, only 50 SNRs are coincident with a H.E.S.S source and in 8 cases the very high-energy (VHE) emission is firmly identified as an SNR. The H.E.S.S. GPS provides us with a legacy for SNR population study in VHE γ -rays and we use this rich data set to extract VHE flux upper limits from all undetected SNRs. Overall, the derived flux upper limits are not in contradiction with the canonical CR paradigm. Assuming this paradigm holds true, we can constrain typical ambient density values around shell-type SNRs to n ≤ 7 cm −3 and electron-to-proton energy fractions above 10 TeV to ϵ ep ≤ 5 × 10 −3 . Furthermore, comparisons of VHE with radio luminosities in non-interacting SNRs reveal a behaviour that is in agreement with the theory of magnetic field lification at shell-type SNRs.
Search for very-high-energyγ-ray emission from Galactic globular clusters with H.E.S.S.
Publisher: EDP Sciences
Date: 13-02-2013
Detection of very-high-energyγ-ray emission from the vicinity of PSR B1706–44 and G 343.1–2.3 with H.E.S.S.
Publisher: EDP Sciences
Date: 17-03-2011
A search for new supernova remnant shells in the Galactic plane with H.E.S.S.
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201730737
Abstract: A search for new supernova remnants (SNRs) has been conducted using TeV γ -ray data from the H.E.S.S. Galactic plane survey. As an identification criterion, shell morphologies that are characteristic for known resolved TeV SNRs have been used. Three new SNR candidates were identified in the H.E.S.S. data set with this method. Extensive multiwavelength searches for counterparts were conducted. A radio SNR candidate has been identified to be a counterpart to HESS J1534−571. The TeV source is therefore classified as a SNR. For the other two sources, HESS J1614−518 and HESS J1912+101, no identifying counterparts have been found, thus they remain SNR candidates for the time being. TeV-emitting SNRs are key objects in the context of identifying the accelerators of Galactic cosmic rays. The TeV emission of the relativistic particles in the new sources is examined in view of possible leptonic and hadronic emission scenarios, taking the current multiwavelength knowledge into account.
Associated Molecular and Atomic Clouds with X-Ray Shell of Superbubble 30 Doradus C in the LMC
Publisher: American Astronomical Society
Date: 09-2021
Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S.
Publisher: EDP Sciences
Date: 23-04-2014
The H.E.S.S. II GRB observation scheme
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968980
Extended carbon line emission in the galaxy: Searching for dark molecular gas along the g328 sightline
Publisher: American Astronomical Society
Date: 11-09-2015
H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud
Publisher: EDP Sciences
Date: 30-01-2015
What do supernova remnants interacting with molecular clouds reveal?
Publisher: AIP
Date: 2009
DOI: 10.1063/1.3125791
Detection of gamma rays from a starburst galaxy
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-11-2009
Abstract: Cosmic rays are thought to be accelerated in the shock waves produced by supernova explosions and can generate gamma rays when they interact with interstellar particles and radiation. Starburst galaxies, with their increased star formation rates, increased stellar explosion rates, and high densities of gas and radiation fields, are considered to be promising sources of gamma-ray emission. Using the High Energy Stereoscopic System (H.E.S.S) array of telescopes, Acero et al. (p. 1080 , published online 24 September) report the detection of gamma rays from one of the closest starburst galaxies, NGC 253. NGC 253 is a spiral galaxy, similar to our own Galaxy, except that its nucleus is undergoing an episode of intense star formation. The H.E.S.S. findings confirm that cosmic-ray acceleration is indeed efficient in starburst galaxies and open up new ways to understand cosmic-ray acceleration.
Erratum: 3 to 12 millimetre studies of dense gas towards the western rim of supernova remnant RX J1713.7−3946
Publisher: Oxford University Press (OUP)
Date: 04-02-2013
DOI: 10.1093/MNRAS/STT061
Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2
Publisher: Oxford University Press (OUP)
Date: 18-11-2014
Search for
γ
Publisher: American Physical Society (APS)
Date: 15-05-2018
Constraints on an Annihilation Signal from a Core of Constant Dark Matter Density around the Milky Way Center with H.E.S.S.
Publisher: American Physical Society (APS)
Date: 24-02-2015
The Gamma-ray Cherenkov Telescope, an end-to end Schwarzschild-Couder telescope prototype proposed for the Cherenkov Telescope Array
Publisher: SPIE
Date: 10-08-2016
DOI: 10.1117/12.2232082
H.E.S.S. observations of RX J1713.7−3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201629790
Abstract: Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7−3946 (also known as G347.3−0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7−3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048° (0.036° above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant’s location. The new H.E.S.S. image of RX J1713.7−3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism.
Galactic TeV Gamma-Ray Sources: A Summary of H.E.S.S. Observations
Publisher: IOP Publishing
Date: 10-2006
Constraints on particle acceleration in SS433/W50 from MAGIC and H.E.S.S. observations
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201731169
Abstract: Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system. Aim. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses ( P orb ~ 13.1 days) and precession of the circumstellar disk ( P pre ~ 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations. Methods. We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to ~40–80 h, depending on the region, was employed. Results. No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be ≲ 10 −12 –10 −13 TeV −1 cm −2 s −1 in an energy interval ranging from ~few × 100 GeV to ~few TeV. Integral flux limits down to ~ 10 −12 –10 −13 ph cm −2 s −1 and ~ 10 −13 –10 −14 ph cm −2 s −1 are obtainedat 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jetregions and on the physics of the jet/medium interactions. Conclusions. Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, q p ≤ 2.5 × 10 −5 , to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields ≳10 μ G is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with E e − up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.
Very-high-energy gamma-ray emission from the direction of the Galactic globular cluster Terzan 5
Publisher: EDP Sciences
Date: 07-2011
Constraints on the multi-TeV particle population in the Coma galaxy cluster with HESS observations
Publisher: EDP Sciences
Date: 04-06-2009
LOOKING INTO THE FIREBALL: ROTSE-III ANDSWIFTOBSERVATIONS OF EARLY GAMMA-RAY BURST AFTERGLOWS
Publisher: American Astronomical Society
Date: 13-08-2009
Inauguration and first light of the GCT-M prototype for the Cherenkov telescope array
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4969027
The gamma-ray Cherenkov telescope for the Cherenkov telescope array
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4969025
Flux upper limits for 47 AGN observed with H.E.S.S. in 2004−2011
Publisher: EDP Sciences
Date: 28-03-2014
Simultaneous X‐Ray and TeV Gamma‐Ray Observation of the TeV Blazar Markarian 421 during 2000 February and May
Publisher: American Astronomical Society
Date: 20-09-2001
DOI: 10.1086/322364
Discovery of a pulsar-powered bow shock nebula in the Small Magellanic Cloud supernova remnant DEM S5
Publisher: Oxford University Press (OUP)
Date: 08-04-2019
DOI: 10.1093/MNRAS/STZ971
Observations of 14 young open star clusters with the HEGRA system of Cherenkov telescopes
Publisher: EDP Sciences
Date: 17-07-2006
The high-energyγ-ray emission of AP Librae
Publisher: EDP Sciences
Date: 10-12-2014
The technical performance of the HEGRA system of imaging air Cherenkov telescopes
Publisher: Elsevier BV
Date: 12-2003
The TeV Energy Spectrum of Markarian 501 Measured with the Stereoscopic Telescope System of HEGRA during 1998 and 1999
Publisher: American Astronomical Society
Date: 10-01-2001
DOI: 10.1086/318321
Measurement of night sky brightness in southern Australia
Publisher: Elsevier BV
Date: 09-2011
Chandra observations of the HII complex G5.89-0.39 and TeV source HESSJ1800-240B
Publisher: AIP
Date: 2012
DOI: 10.1063/1.4772249
Characterizing the γ-ray long-term variability of PKS 2155−304 with H.E.S.S. and Fermi-LAT
Publisher: EDP Sciences
Date: 27-01-2017
DOI: 10.1051/0004-6361/201629419
Abstract: Studying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155−304 is analyzed in the high (HE, 100 MeV E 300 GeV) and very high energy (VHE, E 200 GeV) γ -ray domain. Over the course of ~9 yr of H.E.S.S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index β VHE = 1.10 +0.10 -0.13 ) on timescales larger than one day. An analysis of ~5.5 yr of HE Fermi -LAT data gives consistent results (β HE = 1.20 +0.21 -0.23 , on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior ( β ~ 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection.
H.E.S.S. observations of the Crab during its March 2013 GeV gamma-ray flare
Publisher: EDP Sciences
Date: 02-2014
Dense gas towards the RXJ1713.7–3946 supernova remnant
Publisher: AIP
Date: 2012
DOI: 10.1063/1.4772245
Observations of 54 Active Galactic Nuclei with the HEGRA system of Cherenkov telescopes
Publisher: EDP Sciences
Date: 22-06-2004
The Mopra Southern Galactic Plane CO Survey — Data Release 1
Publisher: Cambridge University Press (CUP)
Date: 2015
DOI: 10.1017/PASA.2015.20
Abstract: We present observations of the first 10° of longitude in the Mopra CO survey of the southern Galactic plane, covering Galactic longitude l = 320–330° and latitude b = ±0.5°, and l = 327–330°, b = +0.5–1.0°. These data have been taken at 35-arcsec spatial resolution and 0.1 km s −1 spectral resolution, providing an unprecedented view of the molecular clouds and gas of the southern Galactic plane in the 109–115 GHz J = 1–0 transitions of 12 CO, 13 CO, C 18 O, and C 17 O. Together with information about the noise statistics from the Mopra telescope, these data can be retrieved from the Mopra CO website and the CSIRO-ATNF data archive.
SEARCH FOR DARK MATTER ANNIHILATION SIGNALS FROM THE FORNAX GALAXY CLUSTER WITH H.E.S.S.
Publisher: American Astronomical Society
Date: 24-04-2012
A Morphological Study of the Supernova Remnant Rx J0852.0-4622 (Vela Jr.)
Publisher: American Astronomical Society
Date: 15-10-2018
Detection of variable VHE γ-ray emission from the extra-galactic γ-ray binary LMC P3
Publisher: EDP Sciences
Date: 02-2018
DOI: 10.1051/0004-6361/201732426
Abstract: Context. Recently, the high-energy (HE, 0.1–100 GeV) γ -ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic γ -ray binary. Aim. This work aims at the detection of very-high-energy (VHE, GeV) γ -ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods. LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.) the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Results. VHE γ -ray emission is detected with a statistical significance of 6.4 σ . The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the 1–10 TeV energy range is (1.4 ± 0.2) × 1035 erg s −1 . A luminosity of (5 ± 1) × 1035 erg s −1 is reached during 20% of the orbit. HE and VHE γ -ray emissions are anti-correlated. LMC P3 is the most luminous γ -ray binary known so far.
VHEγ-ray emission of PKS 2155–304: spectral and temporal variability
Publisher: EDP Sciences
Date: 09-2010
Identification of HESS J1303−631 as a pulsar wind nebula throughγ-ray, X-ray, and radio observations
Publisher: EDP Sciences
Date: 19-11-2012
A multiwavelength view of the flaring state of PKS 2155-304 in 2006
Publisher: EDP Sciences
Date: 03-2012
HESS J1640-465 - an exceptionally luminous TeV -ray supernova remnant
Publisher: Oxford University Press (OUP)
Date: 11-02-2014
DOI: 10.1093/MNRAS/STU139
Extended VHEγ-ray emission towards SGR1806−20, LBV 1806−20, and stellar cluster Cl* 1806−20
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201628695
Abstract: Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) γ -ray source towards the luminous blue variable candidate LBV 1806−20, massive stellar cluster Cl* 1806−20, and magnetar SGR 1806−20. The new VHE source, HESS J1808−204, was detected at a statistical significance of σ (post-trial) with a photon flux normalisation (2.9 ± 0.4 stat ± 0.5 sys ) × 10 −13 ph cm −2 s −1 TeV −1 at 1 TeV and a power-law photon index of 2.3 ± 0.2 stat ± 0.3 sys . The luminosity of this source (0.2 to 10 TeV scaled to distance d = 8.7 kpc) is L VHE ~ 1.6 × 10 34 ( d /8.7 kpc) 2 erg s −1 . The VHE γ -ray emission is extended and is well fit by a single Gaussian with statistical standard deviation of 0.095° ± 0.015°. This extension is similar to that of the synchrotron radio nebula G10.0−0.3, which is thought to be powered by LBV 1806−20. The VHE γ -ray luminosity could be provided by the stellar wind luminosity of LBV 1806−20 by itself and/or the massive star members of Cl* 1806−20. Alternatively, magnetic dissipation (e.g. via reconnection) from SGR 1806−20 can potentially account for the VHE luminosity. The origin and hadronic and/or leptonic nature of the accelerated particles responsible for HESS J1808−204 is not yet clear. If associated with SGR 1806−20, the potentially young age of the magnetar (650 yr) can be used to infer the transport limits of these particles to match the VHE source size. This discovery provides new interest in the potential for high-energy particle acceleration from magnetars, massive stars, and/or stellar clusters.
HESS upper limits on very high energy gamma-ray emission from the microquasar GRS 1915+105
Publisher: EDP Sciences
Date: 04-11-2009
The Crab Nebula and Pulsar between 500 GeV and 80 TeV: Observations with the HEGRA Stereoscopic Air Cerenkov Telescopes
Publisher: American Astronomical Society
Date: 20-10-2004
DOI: 10.1086/423931
A new SNR with TeV shell-type morphology: HESS J1731-347
Publisher: EDP Sciences
Date: 16-06-2011
First deployment and prototype data of HiSCORE
Publisher: IOP Publishing
Date: 02-2013
Possible Evidence for Cosmic-Ray Acceleration in the Type Ia SNR RCW 86: Spatial Correlation between TeV Gamma-Rays and Interstellar Atomic Protons
Publisher: American Astronomical Society
Date: 30-04-2019
Gamma-ray blazar spectra with H.E.S.S. II mono analysis: The case of PKS 2155−304 and PG 1553+113
Publisher: EDP Sciences
Date: 04-2017
DOI: 10.1051/0004-6361/201629427
Abstract: Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment’s sensitivityto lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument’s energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift ≥0.5. The high-frequency peaked BL Lac objects PKS 2155−304 ( z = 0.116) and PG 1553+113 (0.43 z 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155−304 and PG 1553+113 near their SED peaks at energies ≈100 GeV. Methods. Multiple observational c aigns of PKS 2155−304 and PG 1553+113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1–5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155−304 and PG 1553+113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155−304 , which transits near zenith, and 110 GeV for the more northern PG 1553+113 . The measured spectra, well fitted in both cases by a log-parabola spectral model (with a 5.0 σ statistical preference for non-zero curvature for PKS 2155−304 and 4.5 σ for PG 1553+113 ), were found consistent with spectra derived from contemporaneous Fermi -LAT data, indicating a sharp break in the observed spectra of both sources at E ≈ 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi -LAT spectrum of PKS 2155−304 was found to show significant curvature. For PG 1553+113 , however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.
Discovery of VHE emission towards the Carina arm region with the H.E.S.S. telescope array: HESS J1018–589
Publisher: EDP Sciences
Date: 18-04-2012
Erratum: HESS J1640-465 - an exceptionally luminous TeV -ray supernova remnant
Publisher: Oxford University Press (OUP)
Date: 03-06-2014
DOI: 10.1093/MNRAS/STU826
Extended VHE γ-ray emission towards SGR1806-20 and stellar cluster C1 1806-20
Publisher: AIP
Date: 2012
DOI: 10.1063/1.4772250
The HiSCORE experiment and its potential for gamma-ray astronomy
Publisher: IOP Publishing
Date: 02-2013
Pursuing the Origin of the Gamma Rays in RX J1713.7-3946 Quantifying the Hadronic and Leptonic Components
Publisher: American Astronomical Society
Date: 07-2021
Limits on the TeV flux of diffuse gamma rays as measured with the HEGRA air shower array
Publisher: Elsevier BV
Date: 07-2002
Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S.
Publisher: EDP Sciences
Date: 15-01-2013
12 mm line survey of the dense molecular gas towards the W28 field TeV gamma-ray sources
Publisher: Oxford University Press (OUP)
Date: 25-11-2010
Hunting Gravitational Waves with Multi-Messenger Counterparts: Australia's Role
Publisher: Cambridge University Press (CUP)
Date: 2015
DOI: 10.1017/PASA.2015.49
Abstract: The first observations by a worldwide network of advanced interferometric gravitational wave detectors offer a unique opportunity for the astronomical community. At design sensitivity, these facilities will be able to detect coalescing binary neutron stars to distances approaching 400 Mpc, and neutron star–black hole systems to 1 Gpc. Both of these sources are associated with gamma-ray bursts which are known to emit across the entire electromagnetic spectrum. Gravitational wave detections provide the opportunity for ‘multi-messenger’ observations, combining gravitational wave with electromagnetic, cosmic ray, or neutrino observations. This review provides an overview of how Australian astronomical facilities and collaborations with the gravitational wave community can contribute to this new era of discovery, via contemporaneous follow-up observations from the radio to the optical and high energy. We discuss some of the frontier discoveries that will be made possible when this new window to the Universe is opened.
A new method of reconstructing VHE γ -ray spectra: The Template Background Spectrum
Publisher: EDP Sciences
Date: 08-2014
The hardware of the HiSCORE γ-ray and cosmic ray Cherenkov detector
Publisher: AIP
Date: 2012
DOI: 10.1063/1.4772387
H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud(Corrigendum)
Publisher: EDP Sciences
Date: 27-07-2015
HESS observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
Publisher: Oxford University Press (OUP)
Date: 12-06-2012
A Detailed Study of the Interstellar Protons toward the TeVγ-Ray SNR RX J0852.0–4622 (G266.2–1.2, Vela Jr.): The Third Case of theγ-Ray and ISM Spatial Correspondence
Publisher: American Astronomical Society
Date: 17-11-2017
ALMA CO observations of a giant molecular cloud in M 33: Evidence for high-mass star formation triggered by cloud–cloud collisions
Publisher: Oxford University Press (OUP)
Date: 12-06-2020
DOI: 10.1093/PASJ/PSAA045
Abstract: We report the first evidence for high-mass star formation triggered by collisions of molecular clouds in M 33. Using the Atacama Large Millimeter/submillimeter Array, we spatially resolved filamentary structures of giant molecular cloud 37 in M 33 using 12CO(J = 2–1), 13CO(J = 2–1), and C18O(J = 2–1) line emission at a spatial resolution of ∼2 pc. There are two in idual molecular clouds with a systematic velocity difference of ∼6 km s−1. Three continuum sources representing up to ∼10 high-mass stars with spectral types of B0V–O7.5V are embedded within the densest parts of molecular clouds bright in the C18O(J = 2–1) line emission. The two molecular clouds show a complementary spatial distribution with a spatial displacement of ∼6.2 pc, and show a V-shaped structure in the position–velocity diagram. These observational features traced by CO and its isotopes are consistent with those in high-mass star-forming regions created by cloud–cloud collisions in the Galactic and Magellanic Cloud H ii regions. Our new finding in M 33 indicates that cloud–cloud collision is a promising process for triggering high-mass star formation in the Local Group.
TeVγ-ray light curve and energy spectrum of Mkn 421 during its 2001 flare as measured with HEGRA CT1
Publisher: EDP Sciences
Date: 11-2003
Hardware and first results of TUNKA-HiSCORE
Publisher: Elsevier BV
Date: 04-2014
SPECTRAL ANALYSIS AND INTERPRETATION OF THE γ-RAY EMISSION FROM THE STARBURST GALAXY NGC 253
Publisher: American Astronomical Society
Date: 13-09-2012
Probing the extent of the non-thermal emission from the Vela X region at TeV energies with H.E.S.S.
Publisher: EDP Sciences
Date: 16-11-2012
Unidentified TeV sources and the interstellar medium
Publisher: Author(s)
Date: 2017
DOI: 10.1063/1.4968896
Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with H.E.S.S.
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201730824
Abstract: The diffuse very high-energy (VHE GeV) γ -ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130 pc to the Galactic centre (GC), where the flux rapidly decreases. This was initially interpreted as the result of a burst-like injection of energetic particles 10 4 yr ago, but a recent more sensitive H.E.S.S. analysis revealed that the cosmic-ray (CR) density profile drops with the distance to the centre, making data compatible with a steady cosmic PeVatron at the GC. In this paper, we extend this analysis to obtain, for the first time, a detailed characterisation of the correlation with matter and to search for additional features and in idual γ -ray sources in the inner 200 pc. Taking advantage of 250 h of H.E.S.S. data and improved analysis techniques, we perform a detailed morphology study of the diffuse VHE emission observed from the GC ridge and reconstruct its total spectrum. To test the various contributions to the total γ -ray emission, we used an iterative 2D maximum-likelihood approach that allows us to build a phenomenological model of the emission by summing a number of different spatial components. We show that the emission correlated with dense matter covers the full CMZ and that its flux is about half the total diffuse emission flux. We also detect some emission at higher latitude that is likely produced by hadronic collisions of CRs in less dense regions of the GC interstellar medium. We detect an additional emission component centred on the GC and extending over about 15 pc that is consistent with the existence of a strong CR density gradient and confirms the presence of a CR accelerator at the very centre of our Galaxy. We show that the spectrum of full ridge diffuse emission is compatible with that previously derived from the central regions, suggesting that a single population of particles fills the entire CMZ. Finally, we report the discovery of a VHE γ -ray source near the GC radio arc and argue that it is produced by the pulsar wind nebula candidate G0.13−0.11.
Optical reconstruction of dust in the region of supernova remnant RX J1713.7−3946 from astrometric data
Publisher: Springer Science and Business Media LLC
Date: 10-05-2021
H.E.S.S Observations of the Microquasars Cir X-1, Cyg X-1 and 4U 1755-33
Publisher: AIP
Date: 2008
DOI: 10.1063/1.3076651
A Closer Look at the Unidentified TeV Source HESS J1614—518
Publisher: AIP
Date: 2008
DOI: 10.1063/1.3076650
Tunka-HiSCORE – A new array for multi-TeV γ
Publisher:
Elsevier BV
Date:
12-2013
Publisher: Elsevier BV
Date: 12-2013
The GCT camera for the Cherenkov Telescope Array
Publisher: Elsevier BV
Date: 12-2017
Discovery of gamma-ray emission from the extragalactic pulsar wind nebula N 157B with H.E.S.S.
Publisher: EDP Sciences
Date: 29-08-2012
First detection of VHEγ-rays from SN 1006 by HESS
Publisher: EDP Sciences
Date: 06-2010
Search for a Dark Matter Annihilation Signal from the Galactic Center Halo with H.E.S.S.
Publisher: American Physical Society (APS)
Date: 18-04-2011
The exceptionally powerful TeV γ-ray emitters in the Large Magellanic Cloud
Publisher: American Association for the Advancement of Science (AAAS)
Date: 23-01-2015
Abstract: There's a new lab for studying the origins of cosmic rays: our neighbor galaxy, the Large Magellanic Cloud. Astronomers are now making progress on this topic by examining the gamma rays that are produced when cosmic rays interact with gas or lower-energy photons. The H.E.S.S. Collaboration has detected three sources of gamma rays in a variety of forms in the galactic satellite to the Milky Way. The sources include the pulsar wind nebula of N 157B, the supernova remnant N 132D, and the superbubble 30 Dor C. Oddly, supernova 1987A was not detected. Science , this issue p. 406
Search for dark matter annihilation signatures in H.E.S.S. observations of dwarf spheroidal galaxies
Publisher: American Physical Society (APS)
Date: 29-12-2014
Discovery of very high energyγ-ray emission from the BL Lacertae object PKS 0301−243 with H.E.S.S.
Publisher: EDP Sciences
Date: 11-2013
HESS J1943+213: a candidate extreme BL Lacertae object
Publisher: EDP Sciences
Date: 30-03-2011
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