ORCID Profile
0000-0001-6796-3205
Current Organisation
Technische Universität Dortmund
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Publisher: IOP Publishing
Date: 12-2021
DOI: 10.1088/1748-0221/16/12/C12016
Abstract: Starburst galaxies (SBGs) and more in general star-forming galaxies represent a class of galaxies with a high star formation rate (up to 100 M ⊙ /year). Despite their low luminosity, they can be considered as guaranteed “factories” of high energy neutrinos, being “reservoirs” of accelerated cosmic rays and hosting a high density target gas in the central region. In this contribution we present a novel multimessenger study of these sources and the possibility of observing their neutrino signals with the KM3NeT/ARCA telescope. The differential sensitivity for different SBG scenarios is reported considering track-like neutrino events in the 100 GeV–100 PeV energy range.
Publisher: Springer Science and Business Media LLC
Date: 06-2019
Abstract: The ANTARES neutrino telescope has an energy threshold of a few tens of GeV. This allows to study the phenomenon of atmospheric muon neutrino disappearance due to neutrino oscillations. In a similar way, constraints on the 3+1 neutrino model, which foresees the existence of one sterile neutrino, can be inferred. Using data collected by the ANTARES neutrino telescope from 2007 to 2016, a new measurement of Δ m 32 2 and θ 23 has been performed — which is consistent with world best-fit values — and constraints on the 3+1 neutrino model have been derived.
Publisher: American Astronomical Society
Date: 18-01-2018
Publisher: SPIE-Intl Soc Optical Eng
Date: 23-12-2019
Publisher: American Astronomical Society
Date: 16-02-2011
Publisher: IOP Publishing
Date: 31-05-2018
Publisher: Elsevier BV
Date: 07-2012
Publisher: Springer Science and Business Media LLC
Date: 20-11-2019
DOI: 10.1038/S41586-019-1754-6
Abstract: Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission
Publisher: WORLD SCIENTIFIC
Date: 26-02-2018
DOI: 10.1142/10986
Publisher: EDP Sciences
Date: 27-04-2011
Publisher: IOP Publishing
Date: 06-05-2014
Publisher: Cambridge University Press (CUP)
Date: 2022
DOI: 10.1017/PASA.2022.29
Abstract: As TeV gamma-ray astronomy progresses into the era of the Cherenkov Telescope Array (CTA), there is a desire for the capacity to instantaneously follow up on transient phenomena and continuously monitor gamma-ray flux at energies above $10^{12}\\,\\mathrm{eV}$ . To this end, a worldwide network of Imaging Air Cherenkov Telescopes (IACTs) is required to provide triggers for CTA observations and complementary continuous monitoring. An IACT array sited in Australia would contribute significant coverage of the Southern Hemisphere sky. Here, we investigate the suitability of a small IACT array and how different design factors influence its performance. Monte Carlo simulations were produced based on the Small-Sized Telescope (SST) and Medium-Sized Telescope (MST) designs from CTA. Angular resolution improved with larger baseline distances up to 277 m between telescopes, and energy thresholds were lower at 1 000 m altitude than at 0 m. The ${\\sim} 300\\,\\mathrm{GeV}$ energy threshold of MSTs proved more suitable for observing transients than the ${\\sim}1.2\\,\\mathrm{TeV}$ threshold of SSTs. An array of four MSTs at 1 000 m was estimated to give a 5.7 $\\sigma$ detection of an RS Ophiuchi-like nova eruption from a 4-h observation. We conclude that an array of four MST-class IACTs at an Australian site would ideally complement the capabilities of CTA.
Publisher: Springer Science and Business Media LLC
Date: 29-01-2016
Publisher: EDP Sciences
Date: 04-2021
DOI: 10.1051/0004-6361/202038949
Abstract: The flat spectrum radio quasar (FSRQ) PKS 1510−089 is known for its complex multiwavelength behaviour and it is one of only a few FSRQs detected in very-high-energy (VHE, E 100 GeV) γ rays. The VHE γ -ray observations with H.E.S.S. and MAGIC in late May and early June 2016 resulted in the detection of an unprecedented flare, which revealed, for the first time, VHE γ -ray intranight variability for this source. While a common variability timescale of 1.5 h has been found, there is a significant deviation near the end of the flare, with a timescale of ∼20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, a curvature was detected in the VHE γ -ray spectrum of PKS 1510–089, which can be fully explained by the absorption on the part of the extragalactic background light. Optical R -band observations with ATOM revealed a counterpart of the γ -ray flare, even though the detailed flux evolution differs from the VHE γ -ray light curve. Interestingly, a steep flux decrease was observed at the same time as the cessation of the VHE γ -ray flare. In the high-energy (HE, E 100 MeV) γ -ray band, only a moderate flux increase was observed with Fermi -LAT, while the HE γ -ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the γ -ray spectrum indicates that the emission region is located outside of the BLR. Radio very-long-baseline interferometry observations reveal a fast-moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located ∼50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this is indeed a true correlation, the VHE γ rays must have been produced far down in the jet, where turbulent plasma crosses a standing shock.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-11-2014
Abstract: Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Sissa Medialab
Date: 17-08-2021
DOI: 10.22323/1.395.0537
Publisher: IOP Publishing
Date: 23-06-2016
Publisher: EDP Sciences
Date: 06-2014
Publisher: American Astronomical Society
Date: 12-07-2019
Publisher: SPIE-Intl Soc Optical Eng
Date: 07-01-2021
Publisher: Springer Science and Business Media LLC
Date: 05-2017
Publisher: Springer Science and Business Media LLC
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 18-04-2016
DOI: 10.1038/NPHYS3715
Publisher: IOP Publishing
Date: 08-10-2020
Publisher: Elsevier BV
Date: 2020
Publisher: IOP Publishing
Date: 24-02-2016
Publisher: IOP Publishing
Date: 29-06-2011
Publisher: Sissa Medialab
Date: 08-2021
DOI: 10.22323/1.395.1077
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.
Publisher: American Astronomical Society
Date: 16-01-2012
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.
Publisher: Sissa Medialab
Date: 30-07-2021
DOI: 10.22323/1.395.0941
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 09-2019
Publisher: Springer Berlin Heidelberg
Date: 2008
Publisher: EDP Sciences
Date: 30-03-2015
Publisher: American Astronomical Society
Date: 09-05-2017
Publisher: Elsevier BV
Date: 09-2014
Publisher: IOP Publishing
Date: 19-11-2020
Publisher: IOP Publishing
Date: 23-02-2021
Publisher: American Astronomical Society
Date: 11-04-2014
Publisher: Oxford University Press (OUP)
Date: 31-12-2014
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 26-08-2011
Publisher: IOP Publishing
Date: 19-12-2016
Publisher: Springer Science and Business Media LLC
Date: 10-2021
Abstract: KM3NeT/ORCA is a next-generation neutrino telescope optimised for atmospheric neutrino oscillations studies. In this paper, the sensitivity of ORCA to the presence of a light sterile neutrino in a 3+1 model is presented. After three years of data taking, ORCA will be able to probe the active-sterile mixing angles θ 14 , θ 24 , θ 34 and the effective angle θ μe , over a broad range of mass squared difference $$ \\Delta {m}_{41}^2 $$ ∆ m 41 2 ∼ [10 − 5 , 10] eV 2 , allowing to test the eV-mass sterile neutrino hypothesis as the origin of short baseline anomalies, as well as probing the hypothesis of a very light sterile neutrino, not yet constrained by cosmology. ORCA will be able to explore a relevant fraction of the parameter space not yet reached by present measurements.
Publisher: American Astronomical Society
Date: 04-2020
Publisher: American Astronomical Society
Date: 25-11-2019
Publisher: IOP Publishing
Date: 11-11-2014
Publisher: Elsevier BV
Date: 11-2020
Publisher: EDP Sciences
Date: 04-2016
No related grants have been discovered for Dominik Elsaesser.