ORCID Profile
0000-0003-2734-0796
Current Organisation
Observatories of the Carnegie Institution of Washington
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Publisher: American Astronomical Society
Date: 27-10-2009
Publisher: American Astronomical Society
Date: 03-2021
Abstract: We present a study of the optical and near-infrared (NIR) spectra of SN 2013ai along with its light curves. These data range from discovery until 380 days after explosion. SN 2013ai is a fast declining Type II supernova (SN II) with an unusually long rise time, 18.9 ± 2.7 days in the V -band, and a bright V -band peak absolute magnitude of −18.7 ± 0.06 mag. The spectra are dominated by hydrogen features in the optical and NIR. The spectral features of SN 2013ai are unique in their expansion velocities, which, when compared to large s les of SNe II, are more than 1,000 km s −1 faster at 50 days past explosion. In addition, the long rise time of the light curve more closely resembles SNe IIb rather than SNe II. If SN 2013ai is coeval with a nearby compact cluster, we infer a progenitor zero-age main-sequence mass of ∼17 M ⊙ . After performing light-curve modeling, we find that SN 2013ai could be the result of the explosion of a star with little hydrogen mass, a large amount of synthesized 56 Ni, 0.3–0.4 M ⊙ , and an explosion energy of 2.5–3.0 × 10 51 erg. The density structure and expansion velocities of SN 2013ai are similar to those of the prototypical SN IIb, SN 1993J. However, SN 2013ai shows no strong helium features in the optical, likely due to the presence of a dense core that prevents the majority of γ -rays from escaping to excite helium. Our analysis suggests that SN 2013ai could be a link between SNe II and stripped-envelope SNe.
Publisher: American Astronomical Society
Date: 07-1980
DOI: 10.1086/158131
Publisher: American Astronomical Society
Date: 04-1990
DOI: 10.1086/115402
Publisher: American Astronomical Society
Date: 12-2004
DOI: 10.1086/425629
Publisher: IOP Publishing
Date: 27-11-2018
Publisher: American Astronomical Society
Date: 04-1991
DOI: 10.1086/185993
Publisher: American Astronomical Society
Date: 11-06-2014
Publisher: IOP Publishing
Date: 02-1989
DOI: 10.1086/132414
Publisher: EDP Sciences
Date: 18-10-2004
Publisher: American Astronomical Society
Date: 03-2007
DOI: 10.1086/510897
Publisher: American Astronomical Society
Date: 05-10-2020
Publisher: American Astronomical Society
Date: 16-04-2014
Publisher: IOP Publishing
Date: 06-1977
DOI: 10.1086/130110
Publisher: American Astronomical Society
Date: 11-1978
DOI: 10.1086/190553
Publisher: American Astronomical Society
Date: 08-1993
DOI: 10.1086/186970
Publisher: American Astronomical Society
Date: 06-1993
DOI: 10.1086/116602
Publisher: American Astronomical Society
Date: 06-2021
Publisher: American Astronomical Society
Date: 23-01-2018
Publisher: American Astronomical Society
Date: 10-12-1998
DOI: 10.1086/306495
Publisher: American Astronomical Society
Date: 11-07-2018
Publisher: American Astronomical Society
Date: 08-06-2012
Publisher: American Astronomical Society
Date: 02-1985
DOI: 10.1086/162863
Publisher: American Astronomical Society
Date: 11-1984
DOI: 10.1086/162621
Publisher: American Astronomical Society
Date: 09-1987
DOI: 10.1086/165577
Publisher: American Astronomical Society
Date: 08-1976
DOI: 10.1086/154578
Publisher: American Astronomical Society
Date: 25-03-2013
Publisher: American Astronomical Society
Date: 12-2000
DOI: 10.1086/316881
Publisher: American Astronomical Society
Date: 11-11-2010
Publisher: American Astronomical Society
Date: 03-10-2011
Publisher: American Association for the Advancement of Science (AAAS)
Date: 06-05-1988
DOI: 10.1126/SCIENCE.240.4853.750
Abstract: Light from the brightest supernova in almost 400 years arrived at Earth on 23 February 1987. Although located 160,000 light years away in a satellite galaxy of our own known as the Large Magellanic Cloud, this supernova's relative proximity compared to all others that have been observed in modern times has allowed observations, which were never possible before, to be made from space, from detectors on the ground and carried by balloons and airplanes, and from neutrino detectors deep underground. What emerges is a greater understanding of one of the most violent events in the universe, the death of a massive star. For the most part, theoretical expectations have been borne out, but some major surprises have made the event all the more fascinating.
Publisher: American Astronomical Society
Date: 06-1976
DOI: 10.1086/154454
Publisher: American Astronomical Society
Date: 05-1992
DOI: 10.1086/116177
Publisher: American Astronomical Society
Date: 09-1986
DOI: 10.1086/164475
Publisher: Cambridge University Press (CUP)
Date: 2012
DOI: 10.1071/AS11056
Abstract: The photometric properties of Type Ia supernovae (SNe Ia) in the near-infrared as garnered from observations made over the last 30 years are reviewed. During this period, light curves for more than 120 nearby SNe Ia have been published, revealing considerable homogeneity but also some fascinating differences. These data have confirmed that, for all but the fastest declining objects, SNe Ia are essentially perfect standard candles in the near-infrared, displaying only a slight dependence of peak luminosity on decline rate and color.
Publisher: American Astronomical Society
Date: 05-2021
Abstract: The ersity of Type II supernovae (SNe II) is thought to be driven mainly by differences in their progenitor’s hydrogen-rich (H-rich) envelope mass, with SNe IIP having long plateaus (∼100 days) and the most massive H-rich envelopes. However, it is an ongoing mystery why SNe II with short plateaus (tens of days) are rarely seen. Here, we present optical/near-infrared photometric and spectroscopic observations of luminous Type II short-plateau SNe 2006Y, 2006ai, and 2016egz. Their plateaus of about 50–70 days and luminous optical peaks (≲−18.4 mag) indicate significant pre-explosion mass loss resulting in partially stripped H-rich envelopes and early circumstellar material (CSM) interaction. We compute a large grid of MESA + STELLA single-star progenitor and light-curve models with various progenitor zero-age main-sequence (ZAMS) masses, mass-loss efficiencies, explosion energies, 56 Ni masses, and CSM densities. Our model grid shows a continuous population of SNe IIP–IIL–IIb-like light-curve morphology in descending order of H-rich envelope mass. With large 56 Ni masses (≳0.05 M ⊙ ), short-plateau SNe II lie in a confined parameter space as a transitional class between SNe IIL and IIb. For SNe 2006Y, 2006ai, and 2016egz, our findings suggest high-mass red supergiant (RSG) progenitors ( M ZAMS ≃ 18–22 M ⊙ ) with small H-rich envelope masses ( ) that have experienced enhanced mass loss ( ) for the last few decades before the explosion. If high-mass RSGs result in rare short-plateau SNe II, then these events might ease some of the apparent underrepresentation of higher-luminosity RSGs in observed SN II progenitor s les.
Publisher: American Astronomical Society
Date: 03-1983
DOI: 10.1086/160797
Publisher: Oxford University Press (OUP)
Date: 02-06-2022
Abstract: Early-time radiative signals from Type Ia supernovae (SNe Ia) can provide important constraints on the explosion mechanism and the progenitor system. We present observations and analysis of SN 2019np, a nearby SN Ia discovered within 1–2 days after the explosion. Follow-up observations were conducted in optical, ultraviolet, and near-infrared bands, covering the phases from ∼−16.7 d to ∼+ 367.8 d relative to its B-band peak luminosity. The photometric and spectral evolutions of SN 2019np resemble the average behaviour of normal SNe Ia. The absolute B-band peak magnitude and the post-peak decline rate are Mmax(B) = −19.52 ± 0.47 mag and Δm15(B) = 1.04 ± 0.04 mag, respectively. No Hydrogen line has been detected in the nebular-phase spectra of SN 2019np. Assuming that the 56Ni powering the light curve is centrally located, we find that the bolometric light curve of SN 2019np shows a flux excess up to 5.0 per cent in the early phase compared to the radiative diffusion model. Such an extra radiation perhaps suggests the presence of an additional energy source beyond the radioactive decay of central nickel. Comparing the observed colour evolution with that predicted by different models, such as interactions of SN ejecta with circumstellar matter (CSM)/companion star, a double-detonation explosion from a sub-Chandrasekhar mass white dwarf (WD) and surface 56Ni mixing, we propose that the nickel mixing is more favoured for SN 2019np.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-08-2011
Abstract: Most of the progenitors of type Ia supernovae in nearby spiral galaxies may be white dwarf−normal star binary systems.
Publisher: EDP Sciences
Date: 16-07-2009
Publisher: AIP Publishing
Date: 04-1995
DOI: 10.1063/1.2807999
Publisher: American Astronomical Society
Date: 20-04-2008
DOI: 10.1086/529065
Publisher: American Astronomical Society
Date: 10-1993
DOI: 10.1086/173188
Publisher: IOP Publishing
Date: 11-1989
DOI: 10.1086/132558
Publisher: Oxford University Press (OUP)
Date: 09-1981
Publisher: American Astronomical Society
Date: 09-1998
DOI: 10.1086/300499
Publisher: American Astronomical Society
Date: 20-12-1997
DOI: 10.1086/304974
Publisher: Oxford University Press (OUP)
Date: 12-1995
Publisher: American Astronomical Society
Date: 04-1994
DOI: 10.1086/187286
Publisher: Oxford University Press (OUP)
Date: 25-07-2014
Publisher: American Astronomical Society
Date: 26-11-2020
Publisher: American Astronomical Society
Date: 10-07-2007
DOI: 10.1086/518232
Publisher: American Astronomical Society
Date: 23-10-2014
Publisher: American Astronomical Society
Date: 10-01-2003
DOI: 10.1086/344785
Publisher: American Astronomical Society
Date: 10-07-2005
DOI: 10.1086/430405
Publisher: American Astronomical Society
Date: 1987
DOI: 10.1086/164906
Publisher: American Astronomical Society
Date: 08-1977
DOI: 10.1086/155408
Publisher: American Astronomical Society
Date: 10-08-2011
Publisher: Springer Berlin Heidelberg
Date: 2003
Publisher: Oxford University Press (OUP)
Date: 29-11-2018
Publisher: Oxford University Press (OUP)
Date: 12-1981
Publisher: American Astronomical Society
Date: 30-11-2021
Abstract: We present and analyze a near-infrared (NIR) spectrum of the underluminous Type Ia supernova SN 2020qxp/ASASSN-20jq obtained with NIRES at the Keck Observatory, 191 days after B -band maximum. The spectrum is dominated by a number of broad emission features, including the [Fe ii ] at 1.644 μ m, which is highly asymmetric with a tilted top and a peak redshifted by ≈2000 km s −1 . In comparison with 2D non-LTE synthetic spectra computed from 3D simulations of off-center delayed-detonation Chandrasekhar-mass ( M ch ) white dwarf (WD) models, we find good agreement between the observed lines and the synthetic profiles, and are able to unravel the structure of the progenitor’s envelope. We find that the size and tilt of the [Fe ii ] 1.644 μ m profile (in velocity space) is an effective way to determine the location of an off-center delayed-detonation transition (DDT) and the viewing angle, and it requires a WD with a high central density of ∼4 × 10 9 g cm −3 . We also tentatively identify a stable Ni feature around 1.9 μ m characterized by a “pot-belly” profile that is slightly offset with respect to the kinematic center. In the case of SN 2020qxp/ASASSN-20jq, we estimate that the location of the DDT is ∼0.3 M WD off center, which gives rise to an asymmetric distribution of the underlying ejecta. We also demonstrate that low-luminosity and high-density WD SN Ia progenitors exhibit a very strong overlap of Ca and 56 Ni in physical space. This results in the formation of a prevalent [Ca ii ] 0.73 μ m emission feature that is sensitive to asymmetry effects. Our findings are discussed within the context of alternative scenarios, including off-center C/O detonations in He-triggered sub- M Ch WDs and the direct collision of two WDs. Snapshot programs with Gemini/Keck/Very Large Telescope (VLT)/ELT-class instruments and our spectropolarimetry program are complementary to mid-IR spectra by the James Webb Space Telescope (JWST).
Publisher: American Astronomical Society
Date: 10-2020
Publisher: American Astronomical Society
Date: 03-1979
DOI: 10.1086/190577
Publisher: Springer Science and Business Media LLC
Date: 10-2005
DOI: 10.1038/NATURE04189
Abstract: The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.
Publisher: IOP Publishing
Date: 07-2009
DOI: 10.1086/603653
Publisher: American Astronomical Society
Date: 27-07-2016
Publisher: American Astronomical Society
Date: 20-04-2006
DOI: 10.1086/500531
Publisher: American Astronomical Society
Date: 29-12-2011
Publisher: American Astronomical Society
Date: 11-02-2004
DOI: 10.1086/382731
Publisher: American Astronomical Society
Date: 10-2021
Publisher: American Astronomical Society
Date: 04-1996
DOI: 10.1086/177093
Publisher: American Astronomical Society
Date: 04-1996
DOI: 10.1086/177094
Publisher: American Astronomical Society
Date: 05-2006
DOI: 10.1086/498491
Publisher: American Astronomical Society
Date: 20-04-2007
DOI: 10.1086/511665
Publisher: Oxford University Press (OUP)
Date: 27-03-2014
DOI: 10.1093/MNRAS/STU417
Publisher: IOP Publishing
Date: 07-1992
DOI: 10.1086/133028
Publisher: American Astronomical Society
Date: 20-12-1998
DOI: 10.1086/311780
Publisher: American Astronomical Society
Date: 19-01-2010
Publisher: American Astronomical Society
Date: 2006
DOI: 10.1086/498009
Publisher: American Astronomical Society
Date: 05-1986
DOI: 10.1086/114083
Publisher: American Astronomical Society
Date: 13-09-2010
Publisher: American Astronomical Society
Date: 10-08-1999
DOI: 10.1086/307549
Publisher: American Astronomical Society
Date: 03-06-2020
Publisher: American Astronomical Society
Date: 20-12-1995
DOI: 10.1086/309846
Publisher: American Astronomical Society
Date: 13-10-2010
Publisher: American Astronomical Society
Date: 20-08-2003
DOI: 10.1086/376725
Publisher: American Astronomical Society
Date: 10-12-2010
Publisher: American Astronomical Society
Date: 10-11-2002
DOI: 10.1086/342824
Publisher: American Astronomical Society
Date: 10-07-1997
DOI: 10.1086/304268
Publisher: American Astronomical Society
Date: 05-2023
Abstract: We present the largest and most homogeneous collection of near-infrared (NIR) spectra of Type Ia supernovae (SNe Ia): 339 spectra of 98 in idual SNe obtained as part of the Carnegie Supernova Project-II. These spectra, obtained with the FIRE spectrograph on the 6.5 m Magellan Baade telescope, have a spectral range of 0.8–2.5 μ m. Using this s le, we explore the NIR spectral ersity of SNe Ia and construct a template of spectral time series as a function of the light-curve-shape parameter, color stretch s BV . Principal component analysis is applied to characterize the ersity of the spectral features and reduce data dimensionality to a smaller subspace. Gaussian process regression is then used to model the subspace dependence on phase and light-curve shape and the associated uncertainty. Our template is able to predict spectral variations that are correlated with s BV , such as the hallmark NIR features: Mg ii at early times and the H -band break after peak. Using this template reduces the systematic uncertainties in K -corrections by ∼90% compared to those from the Hsiao template. These uncertainties, defined as the mean K -correction differences computed with the color-matched template and observed spectra, are on the level of 4 × 10 −4 mag on average. This template can serve as the baseline spectral energy distribution for light-curve fitters and can identify peculiar spectral features that might point to compelling physics. The results presented here will substantially improve future SN Ia cosmological experiments, for both nearby and distant s les.
Publisher: Oxford University Press (OUP)
Date: 17-12-2018
Publisher: American Astronomical Society
Date: 22-11-2013
Publisher: American Astronomical Society
Date: 21-11-2017
Publisher: American Astronomical Society
Date: 05-2006
DOI: 10.1086/503108
Publisher: American Astronomical Society
Date: 10-1984
DOI: 10.1086/162494
Publisher: American Astronomical Society
Date: 08-1991
DOI: 10.1086/170319
Publisher: American Astronomical Society
Date: 04-1975
DOI: 10.1086/181772
Publisher: American Astronomical Society
Date: 2003
DOI: 10.1086/345571
Publisher: American Astronomical Society
Date: 1988
DOI: 10.1086/165887
Publisher: American Astronomical Society
Date: 06-2001
DOI: 10.1086/320940
Publisher: Oxford University Press (OUP)
Date: 24-04-2023
Abstract: We present ultraviolet (UV) to near-infrared (NIR) observations and analysis of the nearby Type Ia supernova SN 2021fxy. Our observations include UV photometry from Swift/UVOT, UV spectroscopy from HST/STIS, and high-cadence optical photometry with the Swope 1-m telescope capturing intranight rises during the early light curve. Early B − V colours show SN 2021fxy is the first ‘shallow-silicon’ (SS) SN Ia to follow a red-to-blue evolution, compared to other SS objects which show blue colours from the earliest observations. Comparisons to other spectroscopically normal SNe Ia with HST UV spectra reveal SN 2021fxy is one of several SNe Ia with flux suppression in the mid-UV. These SNe also show blueshifted mid-UV spectral features and strong high-velocity Ca ii features. One possible origin of this mid-UV suppression is the increased effective opacity in the UV due to increased line blanketing from high velocity material, but differences in the explosion mechanism cannot be ruled out. Among SNe Ia with mid-UV suppression, SNe 2021fxy and 2017erp show substantial similarities in their optical properties despite belonging to different Branch subgroups, and UV flux differences of the same order as those found between SNe 2011fe and 2011by. Differential comparisons to multiple sets of synthetic SN Ia UV spectra reveal this UV flux difference likely originates from a luminosity difference between SNe 2021fxy and 2017erp, and not differing progenitor metallicities as suggested for SNe 2011by and 2011fe. These comparisons illustrate the complicated nature of UV spectral formation, and the need for more UV spectra to determine the physical source of SNe Ia UV ersity.
Publisher: American Astronomical Society
Date: 13-09-2010
Publisher: American Astronomical Society
Date: 18-10-2016
Publisher: American Astronomical Society
Date: 28-02-2023
Abstract: We present a JWST/MIRI low-resolution mid-infrared (MIR) spectroscopic observation of the normal Type Ia supernova (SN Ia) SN 2021aefx at +323 days past rest-frame B -band maximum light. The spectrum ranges from 4 to 14 μ m and shows many unique qualities, including a flat-topped [Ar iii ] 8.991 μ m profile, a strongly tilted [Co iii ] 11.888 μ m feature, and multiple stable Ni lines. These features provide critical information about the physics of the explosion. The observations are compared to synthetic spectra from detailed non–local thermodynamic equilibrium multidimensional models. The results of the best-fitting model are used to identify the components of the spectral blends and provide a quantitative comparison to the explosion physics. Emission line profiles and the presence of electron capture elements are used to constrain the mass of the exploding white dwarf (WD) and the chemical asymmetries in the ejecta. We show that the observations of SN 2021aefx are consistent with an off-center delayed detonation explosion of a near–Chandrasekhar mass ( M Ch ) WD at a viewing angle of −30° relative to the point of the deflagration to detonation transition. From the strengths of the stable Ni lines, we determine that there is little to no mixing in the central regions of the ejecta. Based on both the presence of stable Ni and the Ar velocity distributions, we obtain a strict lower limit of 1.2 M ⊙ for the initial WD, implying that most sub- M Ch explosions models are not viable models for SN 2021aefx. The analysis here shows the crucial importance of MIR spectra in distinguishing between explosion scenarios for SNe Ia.
Publisher: Oxford University Press (OUP)
Date: 20-02-2018
DOI: 10.1093/MNRAS/STY434
Publisher: American Astronomical Society
Date: 31-08-2017
Publisher: IOP Publishing
Date: 04-1993
DOI: 10.1086/133161
Publisher: American Astronomical Society
Date: 21-11-2017
Publisher: American Astronomical Society
Date: 30-03-2012
Publisher: American Astronomical Society
Date: 30-03-2022
Abstract: We present optical and near-infrared photometric and spectroscopic observations of the fast-declining Type Ia supernova (SN) 2015bo. SN 2015bo is underluminous ( M B = −17.50 ± 0.15 mag) and has a fast-evolving light curve (Δm15( B ) = 1.91 ± 0.01 mag and s BV = 0.48 ± 0.01). It has a unique morphology in the observed V − r color curve, where it is bluer than all other supernovae (SNe) in the comparison s le. A 56 Ni mass of 0.17 ± 0.03 M ⊙ was derived from the peak bolometric luminosity, which is consistent with its location on the luminosity–width relation. Spectroscopically, SN 2015bo is a cool SN in the Branch classification scheme. The velocity evolution measured from spectral features is consistent with 1991bg-like SNe. SN 2015bo has a SN twin (similar spectra) and sibling (same host galaxy), SN 1997cn. Distance moduli of μ = 34.33 ± 0.01 (stat) ±0.11 (sys) mag and μ = 34.34 ± 0.04 (stat) ± 0.12 (sys) mag are derived for SN 2015bo and SN 1997cn, respectively. These distances are consistent at the 0.06 σ level with each other, and they are also consistent with distances derived using surface-brightness fluctuations and redshift-corrected cosmology. This suggests that fast-declining SNe could be accurate distance indicators, which should not be excluded from future cosmological analyses.
Publisher: American Astronomical Society
Date: 15-05-2020
Publisher: EDP Sciences
Date: 04-2022
DOI: 10.1051/0004-6361/202142075
Abstract: The present study is the first of a series of three papers where we characterise the type II supernovae (SNe II) from the Carnegie Supernova Project-I to understand their ersity in terms of progenitor and explosion properties. In this first paper, we present bolometric light curves of 74 SNe II. We outline our methodology to calculate the bolometric luminosity, which consists of the integration of the observed fluxes in numerous photometric bands ( uBgVriYJH ) and black-body (BB) extrapolations to account for the unobserved flux at shorter and longer wavelengths. BB fits were performed using all available broadband data except when line blanketing effects appeared. Photometric bands bluer than r that are affected by line blanketing were removed from the fit, which makes near-infrared (NIR) observations highly important to estimate reliable BB extrapolations to the infrared. BB fits without NIR data produce notably different bolometric light curves, and therefore different estimates of SN II progenitor and explosion properties when data are modelled. We present two methods to address the absence of NIR observations: (a) colour-colour relationships from which NIR magnitudes can be estimated using optical colours, and (b) new prescriptions for bolometric corrections as a function of observed SN II colours. Using our 74 SN II bolometric light curves, we provide a full characterisation of their properties based on several observed parameters. We measured magnitudes at different epochs, as well as durations and decline rates of different phases of the evolution. An analysis of the light-curve parameter distributions was performed, finding a wide range and a continuous sequence of observed parameters which is consistent with previous analyses using optical light curves.
Publisher: American Astronomical Society
Date: 08-1988
DOI: 10.1086/185225
Publisher: American Astronomical Society
Date: 06-2007
DOI: 10.1086/515562
Publisher: Oxford University Press (OUP)
Date: 1992
Abstract: The aim of the study was to investigate the relationship between presented morbidity in consecutive periods of time in the first 35 years of life. Data were collected in a large rural general practice from 1946 to 1990 and covered 103 persons born between 1946 and 1959 in a general practice in the east of The Netherlands. Morbidity scores were calculated for all registered diagnoses in 5-year periods. Morbidity was allocated to three degrees of seriousness, to all atopic disorders, and to eight important diagnosis groups. There were strong correlations between consecutive time periods for all but serious morbidity. The same pattern was found between 0-4 years of age and consecutive periods till the age of 20-25. After this age no significant correlations could be established. Atopic disorders were inter-related in the first 20 years of life. Strong correlations were also found for eczema and lower respiratory tract infections in the first 20 years, while strong correlations were found for accidents and nervous complaints between the ages of 20 and 35. We conclude that causes of morbidity presented in general practice in childhood and adulthood are strongly inter-related over consecutive 5-year periods.
Publisher: American Astronomical Society
Date: 12-2000
DOI: 10.1086/317311
Publisher: American Astronomical Society
Date: 10-12-2000
DOI: 10.1086/317795
Publisher: Oxford University Press (OUP)
Date: 08-1982
Publisher: Springer Science and Business Media LLC
Date: 08-1984
DOI: 10.1038/310554A0
Publisher: American Astronomical Society
Date: 03-11-2017
Publisher: American Astronomical Society
Date: 06-11-2017
Publisher: American Astronomical Society
Date: 02-1980
DOI: 10.1086/157681
Publisher: American Astronomical Society
Date: 12-1996
DOI: 10.1086/310363
Publisher: American Astronomical Society
Date: 17-12-2015
Publisher: American Astronomical Society
Date: 02-1979
DOI: 10.1086/182881
Publisher: American Astronomical Society
Date: 2021
Abstract: We present high-cadence, comprehensive data on the nearby ( D ≃ 33 Mpc) Type II supernova (SN II) 2017ahn, discovered within about one day of the explosion, from the very early phases after explosion to the nebular phase. The observables of SN 2017ahn show a significant evolution over the ≃470 days of our follow-up c aign, first showing prominent, narrow Balmer lines and other high-ionization features purely in emission (i.e., flash spectroscopy features), which progressively fade and lead to a spectroscopic evolution similar to that of more canonical SNe II. Over the same period, the decline of the light curves in all bands is fast, resembling the photometric evolution of linearly declining H-rich core-collapse SNe. The modeling of the light curves and early flash spectra suggests that a complex circumstellar medium surrounds the progenitor star at the time of explosion, with a first dense shell produced during the very late stages of its evolution that is swept up by the rapidly expanding ejecta within the first ∼6 days of the SN evolution, while signatures of interaction are observed also at later phases. Hydrodynamical models support the scenario in which linearly declining SNe II are predicted to arise from massive yellow super- or hypergiants depleted of most of their hydrogen layers.
Publisher: Oxford University Press (OUP)
Date: 10-1984
Publisher: American Astronomical Society
Date: 27-07-2015
Publisher: American Astronomical Society
Date: 02-1980
DOI: 10.1086/157679
Publisher: American Astronomical Society
Date: 09-2000
DOI: 10.1086/301527
Publisher: American Astronomical Society
Date: 03-2022
Abstract: In this paper, we present photometric and spectroscopic observations of the subluminous Type Ia supernova (SN Ia) 2012ij, which has an absolute B -band peak magnitude M B , max = − 17.95 ± 0.15 mag. The B -band light curve exhibits a fast postpeak decline with Δ m 15 ( B ) = 1.86 ± 0.05 mag. All the R - and I / i -band light curves show a weak secondary peak/shoulder feature at about 3 weeks after the peak, like some transitional subclass of SNe Ia, which could result from an incomplete merger of near-infrared (NIR) double peaks. The spectra are characterized by Ti ii and strong Si ii λ 5972 absorption features that are usually seen in low-luminosity objects like SN 1999by. The NIR spectrum before maximum light reveals weak carbon absorption features, implying the existence of unburned materials. We compare the observed properties of SN 2012ij with those predicted by the sub-Chandrasekhar-mass and the Chandrasekhar-mass delayed-detonation models and find that both optical and NIR spectral properties can be explained to some extent by these two models. By comparing the secondary maximum features in the I and i bands, we suggest that SN 2012ij is a transitional object linking normal SNe Ia to typical 91bg-like ones. From the published s le of SNe Ia from the Carnegie Supernova Project II, we estimate that the fraction of SN 2012ij–like SNe Ia is not lower than ∼2%.
Publisher: IOP Publishing
Date: 03-2003
DOI: 10.1086/368229
Publisher: American Astronomical Society
Date: 20-06-2002
DOI: 10.1086/340453
Publisher: American Astronomical Society
Date: 27-01-2016
Publisher: EDP Sciences
Date: 07-2019
DOI: 10.1051/0004-6361/201834389
Abstract: We present an early-phase g -band light curve and visual-wavelength spectra of the normal Type Ia supernova (SN) 2013gy. The light curve is constructed by determining the appropriate S-corrections to transform KAIT natural-system B - and V -band photometry and Carnegie Supernova Project natural-system g -band photometry to the Pan-STARRS1 g -band natural photometric system. A Markov chain Monte Carlo calculation provides a best-fit single power-law function to the first ten epochs of photometry described by an exponent of 2.16 +0.06 −0.06 and a time of first light of MJD 56629.4 +0.1 −0.1 , which is 1.93 +0.12 −0.13 days (i.e., 48 h) before the discovery date (2013 December 4.84 UT) and −19.10 +0.12 −0.13 days before the time of B -band maximum (MJD 56648.5 ± 0.1). The estimate of the time of first light is consistent with the explosion time inferred from the evolution of the Si II λ 6355 Doppler velocity. Furthermore, discovery photometry and previous nondetection limits enable us to constrain the companion radius down to R c ≤ 4 R ⊙ . In addition to our early-time constraints, we used a deep +235 day nebular-phase spectrum from Magellan /IMACS to place a stripped H-mass limit of 0.018 M ⊙ . Combined, these limits effectively rule out H-rich nondegenerate companions.
Publisher: American Astronomical Society
Date: 05-01-2016
Publisher: American Astronomical Society
Date: 29-01-2020
Abstract: We present optical photometry and spectroscopy of the Type Ia supernova SN2018cqj/ATLAS18qtd. The supernova exploded in an isolated region at ∼65 kpc from the S0 galaxy IC 550 at z = 0.0165 ( D ≈ 74 Mpc) and has a redshift consistent with a physical association to this galaxy. Multicolor photometry show that SN2018cqj/ATLAS18qtd is a low-luminosity ( mag), fast-declining Type Ia, with color stretch s BV ≈ 0.6 and B -band decline rate Δ m 15 ( B ) ≈ 1.77 mag. Two nebular-phase spectra obtained as part of the 100IAS survey at +193 and +307 days after peak show the clear detection of a narrow H α line in emission that is resolved in the first spectrum with FWHM ≈ 1200 km s −1 and L H α ≈ 3.8 × 10 37 erg s −1 . The detection of a resolved H α line with a declining luminosity is broadly consistent with recent models where hydrogen is stripped from the nondegenerate companion in a single-degenerate progenitor system. However, the amount of hydrogen consistent with the luminosities of the H α line would be ∼10 −3 M ⊙ , which is significantly less than theoretical model predictions in the classical single-degenerate progenitor systems. SN2018cqj/ATLAS18qtd is the second low-luminosity, fast-declining SN Ia after SN2018fhw/ASASSN-18tb that shows narrow H α in emission in its nebular-phase spectra.
Publisher: American Astronomical Society
Date: 28-04-2016
Publisher: Oxford University Press (OUP)
Date: 03-1984
Publisher: Oxford University Press (OUP)
Date: 02-05-2014
DOI: 10.1093/MNRAS/STU610
Publisher: EDP Sciences
Date: 30-01-2020
DOI: 10.1051/0004-6361/201936619
Abstract: Supernova LSQ13abf was discovered soon after explosion by the La Silla-QUEST Survey and then followed by the Carnegie Supernova Project II at its optical and near-IR wavelengths. Our analysis indicates that LSQ13abf was discovered within two days of explosion and its first ≈10 days of evolution reveal a B -band light curve with an abrupt drop in luminosity. Contemporaneously, the V -band light curve exhibits a rise towards a first peak and the r - and i -band light curves show no early peak. The early light-curve evolution of LSQ13abf is reminiscent of the post-explosion cooling phase observed in the Type Ib SN 2008D, and the similarity between the two objects extends over weeks. Spectroscopically, LSQ13abf also resembles SN 2008D, with P Cygni He I features that strengthen over several weeks. Spectral energy distributions are constructed from the broad-bandphotometry, a UVOIR light curve is constructed by fitting black-body (BB) functions, and the underlying BB-temperature and BB-radius profiles are estimated. Explosion parameters are estimated by simultaneously fitting an Arnett model to the UVOIR light curve and the velocity evolution derived from spectral features, and an in addition to a post-shock breakout cooling model to the first two epochs of the bolometric evolution. This combined model suggests an explosion energy of 1.27 ± 0.23 × 10 51 ergs, in addition to a relatively high ejecta mass of 5.94 ± 1.10 M ⊙ , a 56 Ni mass of 0.16 ± 0.02 M ⊙ , and a progenitor-star radius of 28.0 ± 7.5 R ⊙ . The ejecta mass suggests the origins of LSQ13abf lie with a 25 M ⊙ zero-age-main-sequence mass progenitor and its estimated radius is three times larger compared to the result obtained from the same analysis applied to observations of SN 2008D, and nine times larger compared to SN 1999ex. Alternatively, a comparison of hydrodynamical simulations of ≳20−25 M ⊙ zero-age-main-sequence progenitors that evolve to pre-supernova envelope masses of ≲10 M ⊙ and extended (∼100 R ⊙ ) envelopes also broadly match the observations of LSQ13abf.
Publisher: American Astronomical Society
Date: 08-1997
DOI: 10.1086/118506
Publisher: American Astronomical Society
Date: 09-2001
DOI: 10.1086/322120
Publisher: American Astronomical Society
Date: 30-11-2021
Abstract: We present a multiwavelength photometric and spectroscopic analysis of 13 super-Chandrasekhar-mass/2003fg-like Type Ia supernovae (SNe Ia). Nine of these objects were observed by the Carnegie Supernova Project. The 2003fg-like SNe have slowly declining light curves (Δ m 15 ( B ) 1.3 mag), and peak absolute B -band magnitudes of −19 M B −21 mag. Many of the 2003fg-like SNe are located in the same part of the luminosity–width relation as normal SNe Ia. In the optical B and V bands, the 2003fg-like SNe look like normal SNe Ia, but at redder wavelengths they erge. Unlike other luminous SNe Ia, the 2003fg-like SNe generally have only one i -band maximum, which peaks after the epoch of the B -band maximum, while their near-IR (NIR) light-curve rise times can be ≳40 days longer than those of normal SNe Ia. They are also at least 1 mag brighter in the NIR bands than normal SNe Ia, peaking above M H = −19 mag, and generally have negative Hubble residuals, which may be the cause of some systematics in dark-energy experiments. Spectroscopically, the 2003fg-like SNe exhibit peculiarities such as unburnt carbon well past maximum light, a large spread (8000–12,000 km s −1 ) in Si ii λ 6355 velocities at maximum light with no rapid early velocity decline, and no clear H -band break at +10 days. We find that SNe with a larger pseudo-equivalent width of C ii at maximum light have lower Si ii λ 6355 velocities and more slowly declining light curves. There are also multiple factors that contribute to the peak luminosity of 2003fg-like SNe. The explosion of a C–O degenerate core inside a carbon-rich envelope is consistent with these observations. Such a configuration may come from the core-degenerate scenario.
Publisher: American Astronomical Society
Date: 04-1988
DOI: 10.1086/114705
Publisher: American Astronomical Society
Date: 03-2023
Abstract: We present multiwavelength time-series spectroscopy of SN 2013aa and SN 2017cbv, two Type Ia supernovae (SNe Ia) on the outskirts of the same host galaxy, NGC 5643. This work utilizes new nebular-phase near-infrared (NIR) spectra obtained by the Carnegie Supernova Project-II, in addition to previously published optical and NIR spectra. Using nebular-phase [Fe ii ] lines in the optical and NIR, we examine the explosion kinematics and test the efficacy of several common emission-line-fitting techniques. The NIR [Fe ii ] 1.644 μ m line provides the most robust velocity measurements against variations due to the choice of the fit method and line blending. The resulting effects on velocity measurements due to choosing different fit methods, initial fit parameters, continuum and line profile functions, and fit region boundaries were also investigated. The NIR [Fe ii ] velocities yield the same radial shift direction as velocities measured using the optical [Fe ii ] λ 7155 line, but the sizes of the shifts are consistently and substantially lower, pointing to a potential issue in optical studies. The NIR [Fe ii ] 1.644 μ m emission profile shows a lack of significant asymmetry in both SNe, and the observed low velocities elevate the importance for correcting for any velocity contribution from the host galaxy’s rotation. The low [Fe ii ] velocities measured in the NIR at nebular phases disfavor progenitor scenarios in close double-degenerate systems for both SN 2013aa and SN 2017cbv. The time evolution of the NIR [Fe ii ] 1.644 μ m line also indicates moderately high progenitor white dwarf central density and potentially high magnetic fields.
Publisher: American Astronomical Society
Date: 03-1989
DOI: 10.1086/167236
Publisher: Oxford University Press (OUP)
Date: 03-1984
Publisher: American Astronomical Society
Date: 27-01-2017
Publisher: IOP Publishing
Date: 12-1975
DOI: 10.1086/129879
Publisher: Oxford University Press (OUP)
Date: 13-12-2013
Publisher: Oxford University Press (OUP)
Date: 04-12-2019
Abstract: We place statistical constraints on Type Ia supernova (SN Ia) progenitors using 227 nebular-phase spectra of 111 SNe Ia. We find no evidence of stripped companion emission in any of the nebular-phase spectra. Upper limits are placed on the amount of mass that could go undetected in each spectrum using recent hydrodynamic simulations. With these null detections, we place an observational 3σ upper limit on the fraction of SNe Ia that are produced through the classical H-rich non-degenerate companion scenario of $\\lt 5.5 {{\\ \\rm per\\ cent}}$. Additionally, we set a tentative 3σ upper limit otan He star progenitor scenarios of $\\lt 6.4 {{\\ \\rm per\\ cent}}$, although further theoretical modelling is required. These limits refer to our most representative s le including normal, 91bg-like, 91T-like, and ‘super-Chandrasekhar’ SNe Ia but excluding SNe Iax and SNe Ia-CSM. As part of our analysis, we also derive a Nebular Phase Phillips Relation, which approximates the brightness of an SN Ia from 150 to 500 d after maximum using the peak magnitude and decline rate parameter Δm15(B).
Publisher: American Astronomical Society
Date: 06-2022
Abstract: We present early-time photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2021aefx. The early-time u -band light curve shows an excess flux when compared to normal SNe Ia. We suggest that the early excess blue flux may be due to a rapid change in spectral velocity in the first few days post explosion, produced by the emission of the Ca ii H& K feature passing from the u to the B bands on the timescale of a few days. This effect could be dominant for all SNe Ia that have broad absorption features and early-time velocities over 25,000 km s −1 . It is likely to be one of the main causes of early excess u -band flux in SNe Ia that have early-time high velocities. This effect may also be dominant in the UV filters, as well as in places where the SN spectral energy distribution is quickly rising to longer wavelengths. The rapid change in velocity can only produce a monotonic change (in flux-space) in the u band. For objects that explode at lower velocities, and have a more structured shape in the early excess emission, there must also be an additional parameter producing the early-time ersity. More early-time observations, in particular early spectra, are required to determine how prominent this effect is within SNe Ia.
Publisher: IOP Publishing
Date: 04-2014
DOI: 10.1086/676019
Publisher: American Astronomical Society
Date: 02-12-2008
Publisher: American Astronomical Society
Date: 09-1979
DOI: 10.1086/157324
Publisher: American Astronomical Society
Date: 03-1980
DOI: 10.1086/183196
Publisher: Oxford University Press (OUP)
Date: 09-1985
Publisher: American Astronomical Society
Date: 19-06-2012
Publisher: American Scientific Publishers
Date: 05-2016
Publisher: American Astronomical Society
Date: 10-2022
Abstract: 1991T-like supernovae are the luminous, slow-declining extreme of the Branch shallow-silicon (SS) subclass of Type Ia supernovae. They are distinguished by extremely weak Ca ii H & K and Si ii λ 6355 and strong Fe iii absorption features in their optical spectra at pre-maximum phases, and have long been suspected to be over-luminous compared to normal Type Ia supernovae. In this paper, the pseudo-equivalent width of the Si ii λ 6355 absorption obtained at light curve phases from ≤ +10 days is combined with the morphology of the i -band light curve to identify a s le of 1991T-like supernovae in the Carnegie Supernova Project II. Hubble diagram residuals show that, at optical as well as near-infrared wavelengths, these events are over-luminous by ∼0.1–0.5 mag with respect to the less extreme Branch SS (1999aa-like) and Branch core-normal supernovae with similar B -band light-curve decline rates.
Publisher: IOP Publishing
Date: 08-1990
DOI: 10.1086/132713
Publisher: IOP Publishing
Date: 08-1990
DOI: 10.1086/132714
Publisher: Springer Science and Business Media LLC
Date: 03-1987
DOI: 10.1007/BF00668157
Publisher: EDP Sciences
Date: 20-04-2016
Publisher: EDP Sciences
Date: 08-2019
DOI: 10.1051/0004-6361/201935420
Abstract: We present the results of the monitoring c aign of the Type IIn supernova (SN) 2018cnf (a.k.a. ASASSN-18mr). It was discovered about ten days before the maximum light (on MJD = 58 293.4 ± 5.7 in the V band, with M V = −18.13 ± 0.15 mag). The multiband light curves show an immediate post-peak decline with some minor luminosity fluctuations, followed by a flattening starting about 40 days after maximum. The early spectra are relatively blue and show narrow Balmer lines with P Cygni profiles. Additionally, Fe II, O I, He I, and Ca II are detected. The spectra show little evolution with time and with intermediate-width features becoming progressively more prominent, indicating stronger interaction of the SN ejecta with the circumstellar medium. The inspection of archival images from the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey has revealed a variable source at the SN position with a brightest detection in December 2015 at M r = −14.66 ± 0.17 mag. This was likely an eruptive phase from the massive progenitor star that started from at least mid-2011, and that produced the circumstellar environment within which the star exploded as a Type IIn SN. The overall properties of SN 2018cnf closely resemble those of transients such as SN 2009ip. This similarity favours a massive hypergiant, perhaps a luminous blue variable, as progenitor for SN 2018cnf.
Publisher: American Astronomical Society
Date: 02-2023
Abstract: We present JWST near-infrared (NIR) and mid-infrared (MIR) spectroscopic observations of the nearby normal Type Ia supernova (SN) SN 2021aefx in the nebular phase at +255 days past maximum light. Our Near Infrared Spectrograph (NIRSpec) and Mid Infrared Instrument observations, combined with ground-based optical data from the South African Large Telescope, constitute the first complete optical+NIR+MIR nebular SN Ia spectrum covering 0.3–14 μ m. This spectrum unveils the previously unobserved 2.5−5 μ m region, revealing strong nebular iron and stable nickel emission, indicative of high-density burning that can constrain the progenitor mass. The data show a significant improvement in sensitivity and resolution compared to previous Spitzer MIR data. We identify numerous NIR and MIR nebular emission lines from iron-group elements as well as lines from the intermediate-mass element argon. The argon lines extend to higher velocities than the iron-group elements, suggesting stratified ejecta that are a hallmark of delayed-detonation or double-detonation SN Ia models. We present fits to simple geometric line profiles to features beyond 1.2 μ m and find that most lines are consistent with Gaussian or spherical emission distributions, while the [Ar iii ] 8.99 μ m line has a distinctively flat-topped profile indicating a thick spherical shell of emission. Using our line profile fits, we investigate the emissivity structure of SN 2021aefx and measure kinematic properties. Continued observations of SN 2021aefx and other SNe Ia with JWST will be transformative to the study of SN Ia composition, ionization structure, density, and temperature, and will provide important constraints on SN Ia progenitor and explosion models.
Publisher: American Astronomical Society
Date: 10-06-2000
DOI: 10.1086/308939
Publisher: Oxford University Press (OUP)
Date: 14-03-2018
DOI: 10.1093/MNRAS/STY632
Publisher: Oxford University Press (OUP)
Date: 28-06-2023
Abstract: We present photometric and spectroscopic observations and analysis of SN 2021bxu (ATLAS21dov), a low-luminosity, fast-evolving Type IIb supernova (SN). SN 2021bxu is unique, showing a large initial decline in brightness followed by a short plateau phase. With $M_r = -15.93 \\pm 0.16\\, \\mathrm{mag}$ during the plateau, it is at the lower end of the luminosity distribution of stripped-envelope supernovae (SE-SNe) and shows a distinct ∼10 d plateau not caused by H- or He-recombination. SN 2021bxu shows line velocities which are at least $\\sim 1500\\, \\mathrm{km\\, s^{-1}}$ slower than typical SE-SNe. It is photometrically and spectroscopically similar to Type IIb SNe during the photospheric phases of evolution, with similarities to Ca-rich IIb SNe. We find that the bolometric light curve is best described by a composite model of shock interaction between the ejecta and an envelope of extended material, combined with a typical SN IIb powered by the radioactive decay of 56Ni. The best-fitting parameters for SN 2021bxu include a 56Ni mass of $M_{\\mathrm{Ni}} = 0.029^{+0.004}_{-0.005}\\, \\mathrm{{\\rm M}_{\\odot }}$, an ejecta mass of $M_{\\mathrm{ej}} = 0.61^{+0.06}_{-0.05}\\, \\mathrm{{\\rm M}_{\\odot }}$, and an ejecta kinetic energy of $K_{\\mathrm{ej}} = 8.8^{+1.1}_{-1.0} \\times 10^{49}\\, \\mathrm{erg}$. From the fits to the properties of the extended material of Ca-rich IIb SNe we find a trend of decreasing envelope radius with increasing envelope mass. SN 2021bxu has MNi on the low end compared to SE-SNe and Ca-rich SNe in the literature, demonstrating that SN 2021bxu-like events are rare explosions in extreme areas of parameter space. The progenitor of SN 2021bxu is likely a low-mass He star with an extended envelope.
Publisher: IOP Publishing
Date: 06-2007
DOI: 10.1086/520097
Publisher: American Astronomical Society
Date: 02-1995
DOI: 10.1086/117315
Publisher: American Astronomical Society
Date: 11-1983
DOI: 10.1086/161470
Publisher: American Astronomical Society
Date: 09-2003
DOI: 10.1086/376865
Publisher: American Astronomical Society
Date: 29-08-2019
Abstract: We present a new and independent determination of the local value of the Hubble constant based on a calibration of the tip of the red giant branch (TRGB) applied to Type Ia supernovae (SNe Ia). We find a value of H 0 = 69.8 ± 0.8 (±1.1% stat) ± 1.7 (±2.4% sys) km s −1 Mpc −1 . The TRGB method is both precise and accurate and is parallel to but independent of the Cepheid distance scale. Our value sits midway in the range defined by the current Hubble tension. It agrees at the 1.2 σ level with that of the Planck Collaboration et al. estimate and at the 1.7 σ level with the Hubble Space Telescope ( HST ) SHoES measurement of H 0 based on the Cepheid distance scale. The TRGB distances have been measured using deep HST Advanced Camera for Surveys imaging of galaxy halos. The zero-point of the TRGB calibration is set with a distance modulus to the Large Magellanic Cloud of 18.477 ± 0.004 (stat) ± 0.020 (sys) mag, based on measurement of 20 late-type detached eclipsing binary stars, combined with an HST parallax calibration of a 3.6 μ m Cepheid Leavitt law based on Spitzer observations. We anchor the TRGB distances to galaxies that extend our measurement into the Hubble flow using the recently completed Carnegie Supernova Project I ( CSP-I ) s le containing about 100 well-observed SNe Ia . There are several advantages of halo TRGB distance measurements relative to Cepheid variables these include low halo reddening, minimal effects of crowding or blending of the photometry, only a shallow (calibrated) sensitivity to metallicity in the I band, and no need for multiple epochs of observations or concerns of different slopes with period. In addition, the host masses of our TRGB host-galaxy s le are higher, on average, than those of the Cepheid s le, better matching the range of host-galaxy masses in the CSP-I distant s le and reducing potential systematic effects in the SNe Ia measurements.
Publisher: American Astronomical Society
Date: 09-1991
DOI: 10.1086/115938
Publisher: IOP Publishing
Date: 12-1978
DOI: 10.1086/130400
Publisher: American Astronomical Society
Date: 03-1978
DOI: 10.1086/155921
Publisher: Oxford University Press (OUP)
Date: 03-1984
Publisher: Oxford University Press (OUP)
Date: 09-1982
Publisher: American Astronomical Society
Date: 10-06-2013
Publisher: American Astronomical Society
Date: 10-06-2002
DOI: 10.1086/341552
Publisher: IOP Publishing
Date: 02-1981
DOI: 10.1086/130766
Publisher: American Astronomical Society
Date: 31-05-2012
Publisher: Oxford University Press (OUP)
Date: 04-1982
Publisher: American Astronomical Society
Date: 05-2014
Publisher: American Astronomical Society
Date: 10-1982
DOI: 10.1086/160372
Publisher: American Astronomical Society
Date: 16-04-2019
Publisher: American Astronomical Society
Date: 12-09-2018
Publisher: American Astronomical Society
Date: 08-03-2013
Publisher: Oxford University Press (OUP)
Date: 11-07-2019
Abstract: Type II supernovae (SNe II) show strong hydrogen features in their spectra throughout their whole evolution, while type IIb supernovae (SNe IIb) spectra evolve from dominant hydrogen lines at early times to increasingly strong helium features later on. However, it is currently unclear whether the progenitors of these SN types form a continuum in pre-SN hydrogen mass or whether they are physically distinct. SN light-curve morphology directly relates to progenitor and explosion properties such as the amount of hydrogen in the envelope, the pre-SN radius, the explosion energy, and the synthesized mass of radioactive material. In this work, we study the morphology of the optical-wavelength light curves of hydrogen-rich SNe II and hydrogen-poor SNe IIb to test whether an observational continuum exists between the two. Using a s le of 95 SNe (73 SNe II and 22 SNe IIb), we define a range of key observational parameters and present a comparative analysis between both types. We find a lack of events that bridge the observed properties of SNe II and IIb. Light-curve parameters such as rise times and post-maximum decline rates and curvatures clearly separate both SN types and we therefore conclude that there is no continuum, with the two SN types forming two observationally distinct families. In the V band a rise time of 17 d (SNe II lower and SNe IIb higher), and a magnitude difference between 30 and 40 d post-explosion of 0.4 mag (SNe II lower and SNe IIb higher) serve as approximate thresholds to differentiate both types.
Publisher: Oxford University Press (OUP)
Date: 11-1982
Publisher: Oxford University Press (OUP)
Date: 02-06-2018
Publisher: American Astronomical Society
Date: 18-11-2019
Publisher: Oxford University Press (OUP)
Date: 03-01-2020
Abstract: This paper describes the rapidly evolving and unusual supernova LSQ13ddu, discovered by the La Silla-QUEST survey. LSQ13ddu displayed a rapid rise of just 4.8 ± 0.9 d to reach a peak brightness of −19.70 ± 0.02 mag in the LSQgr band. Early spectra of LSQ13ddu showed the presence of weak and narrow $\\mathrm{ He}\\, {\\small I}$ features arising from interaction with circumstellar material (CSM). These interaction signatures weakened quickly, with broad features consistent with those seen in stripped-envelope SNe becoming dominant around two weeks after maximum. The narrow $\\mathrm{ He}\\, {\\small I}$ velocities are consistent with the wind velocities of luminous blue variables but its spectra lack the typically seen hydrogen features. The fast and bright early light curve is inconsistent with radioactive 56Ni powering but can be explained through a combination of CSM interaction and an underlying 56Ni decay component that dominates the later time behaviour of LSQ13ddu. Based on the strength of the underlying broad features, LSQ13ddu appears deficient in He compared to standard SNe Ib.
Publisher: Oxford University Press (OUP)
Date: 02-05-2020
Abstract: We present optical and near-infrared data of three Type II supernovae (SNe II), SN 2008bm, SN 2009aj, and SN 2009au. These SNe display the following common characteristics: signs of early interaction of the ejecta with circumstellar material (CSM), blue B − V colours, weakness of metal lines, low expansion velocities, and V-band absolute magnitudes 2–3 mag brighter than those expected for normal SNe II based on their expansion velocities. Two more SNe reported in the literature (SN 1983K and LSQ13fn) share properties similar to our s le. Analysing this set of five SNe II, which are luminous for their low expansion velocities (LLEV), we find that their properties can be reproduced assuming ejecta–CSM interaction that lasts between 4 and 11 weeks post-explosion. The contribution of this interaction to the radiation field seems to be the dominant component determining the observed weakness of metal lines in the spectra rather than the progenitor metallicity. Based on hydrodynamic simulations, we find that the interaction of the ejecta with a CSM of ∼3.6 M⊙ can reproduce the light curves and expansion velocities of SN 2009aj. Using data collected by the Chilean Automatic Supernova Search, we estimate an upper limit for the LLEV SNe II fraction to be 2–4 per cent of all normal SNe II. With the current data set, it is not clear whether the LLEV events are a separated class of SNe II with a different progenitor system, or whether they are the extreme of a continuum mediated by CSM interaction with the rest of the normal SN II population.
Publisher: American Astronomical Society
Date: 21-12-2018
Publisher: American Astronomical Society
Date: 11-12-2018
Publisher: American Astronomical Society
Date: 20-10-2008
DOI: 10.1086/589937
Publisher: American Astronomical Society
Date: 02-1998
DOI: 10.1086/311140
Publisher: Oxford University Press (OUP)
Date: 13-10-2015
Publisher: American Astronomical Society
Date: 04-12-2019
Publisher: IOP Publishing
Date: 03-2008
DOI: 10.1086/533458
Publisher: American Astronomical Society
Date: 18-06-2019
Publisher: American Astronomical Society
Date: 10-09-2020
Publisher: IOP Publishing
Date: 11-1993
DOI: 10.1086/133302
Publisher: EDP Sciences
Date: 06-2020
DOI: 10.1051/0004-6361/201936654
Abstract: We present ultra-violet (UV) to mid-infrared (MIR) observations of the long-lasting Type IIn supernova (SN) 2013L obtained by the Carnegie Supernova Project II beginning two days after discovery and extending until +887 days (d). The SN reached a peak r -band absolute magnitude of ≈−19 mag and an even brighter UV peak, and its light curve evolution resembles that of SN 1988Z. The spectra of SN 2013L are dominated by hydrogen emission features, characterized by three components attributed to different emission regions. A unique feature of this Type IIn SN is that, apart from the first epochs, the blue shifted line profile is dominated by the macroscopic velocity of the expanding shock wave of the SN. We are therefore able to trace the evolution of the shock velocity in the dense and partially opaque circumstellar medium (CSM), from ∼4800 km s −1 at +48 d, decreasing as t −0.23 to ∼2700 km s −1 after a year. We performed spectral modeling of both the broad- and intermediate-velocity components of the H α line profile. The high-velocity component is consistent with emission from a radially thin, spherical shell located behind the expanding shock with emission wings broadened by electron scattering. We propose that the intermediate component originates from preionized gas from the unshocked dense CSM with the same velocity as the narrow component, ∼100 km s −1 , but also that it is broadened by electron scattering. These features provide direct information about the shock structure, which is consistent with model calculations. The spectra exhibit broad O I and [O I ] lines that emerge at ≳+144 d and broad Ca II features. The spectral continua and the spectral energy distributions (SEDs) of SN 2013L after +132 d are well reproduced by a two-component black-body (BB) model one component represents emitting material with a temperature between 5 × 10 3 and 1.5 × 10 4 K (hot component) and the second component is characterized by a temperature around 1–1.5 × 10 3 K (warm component). The warm component dominates the emission at very late epochs (≳+400 d), as is evident from both the last near infrared (NIR) spectrum and MIR observations obtained with the Spitzer Space Telescope. Using the BB fit to the SEDs, we constructed a bolometric light curve that was modeled together with the unshocked CSM velocity and the shock velocity derived from the H α line modeling. The circumstellar-interaction model of the bolometric light curve reveals a mass-loss rate history with large values (1.7 × 10 −2 − 0.15 M ⊙ yr −1 ) over the ∼25−40 years before explosion, depending on the radiative efficiency and anisotropies in the CSM. The drop in the light curve at ∼350 days and the presence of electron scattering wings at late epochs indicate an anisotropic CSM. The mass-loss rate values and the unshocked-CSM velocity are consistent with the characteristics of a massive star, such as a luminous blue variable (LBV) undergoing strong eruptions, similar to η Carinae. Our analysis also suggests a scenario where pre-existing dust grains have a distribution that is characterized by a small covering factor.
Publisher: American Astronomical Society
Date: 18-11-2020
Publisher: American Astronomical Society
Date: 03-1981
DOI: 10.1086/158721
Publisher: American Astronomical Society
Date: 11-1978
DOI: 10.1086/156542
Publisher: American Astronomical Society
Date: 20-08-2005
DOI: 10.1086/431422
Publisher: American Astronomical Society
Date: 02-1993
DOI: 10.1086/186256
Publisher: American Astronomical Society
Date: 25-01-2012
Publisher: American Astronomical Society
Date: 08-1980
DOI: 10.1086/183301
Publisher: American Astronomical Society
Date: 04-1987
DOI: 10.1086/184874
Publisher: American Astronomical Society
Date: 19-04-2017
Publisher: American Astronomical Society
Date: 1985
DOI: 10.1086/162783
Publisher: IOP Publishing
Date: 06-1994
DOI: 10.1086/133417
Publisher: IOP Publishing
Date: 1983
DOI: 10.1086/131114
Publisher: Oxford University Press (OUP)
Date: 24-02-2018
DOI: 10.1093/MNRAS/STY508
Publisher: American Astronomical Society
Date: 02-2022
Abstract: We present 75 near-infrared (NIR 0.8−2.5 μ m) spectra of 34 stripped-envelope core-collapse supernovae (SESNe) obtained by the Carnegie Supernova Project-II (CSP-II), encompassing optical spectroscopic Types IIb, Ib, Ic, and Ic-BL. The spectra range in phase from pre-maximum to 80 days past maximum. This unique data set constitutes the largest NIR spectroscopic s le of SESNe to date. NIR spectroscopy provides observables with additional information that is not available in the optical. Specifically, the NIR contains the strong lines of He i and allows a more detailed look at whether Type Ic supernovae are completely stripped of their outer He layer. The NIR spectra of SESNe have broad similarities, but closer examination through statistical means reveals a strong dichotomy between NIR “He-rich” and “He-poor” SNe. These NIR subgroups correspond almost perfectly to the optical IIb/Ib and Ic/Ic-BL types, respectively. The largest difference between the two groups is observed in the 2 μ m region, near the He i λ 2.0581 μ m line. The ision between the two groups is not an arbitrary one along a continuous sequence. Early spectra of He-rich SESNe show much stronger He i λ 2.0581 μ m absorption compared to the He-poor group, but with a wide range of profile shapes. The same line also provides evidence for trace amounts of He in half of our SNe in the He-poor group.
Publisher: American Astronomical Society
Date: 26-06-2015
Publisher: Springer Science and Business Media LLC
Date: 14-01-2019
Publisher: Oxford University Press (OUP)
Date: 03-04-2019
DOI: 10.1093/MNRAS/STZ953
Abstract: As part of the 100IAS survey, a program aimed to obtain nebular-phase spectra for a volume-limited and homogeneous s le of Type Ia supernovae (SNe Ia), we observed ASASSN-18tb (SN 2018fhw) at 139 d past maximum light. ASASSN-18tb was a fast-declining, sub-luminous event that fits well within the observed photometric and spectroscopic distributions of the SN Ia population. We detect a prominent H α emission line (LH α = 2.2 ± 0.2 × 1038 ergs s−1) with FWHM ≈ 1100 km s−1 in the nebular-phase spectrum of this SN Ia. High-luminosity H α emission (LH α ≳ 1040 ergs s−1) has previously been discovered in a rare class of SNe Ia-like objects showing circum-stellar medium (CSM) interactions (SNe Ia–CSM). They predominantly belong to overluminous (Mmax & −19 mag in optical) 1991T-like SNe Ia and are exclusively found in star-forming galaxies. By contrast, ASASSN-18tb is a sub-luminous SN Ia (MB,max ∼ −17.7 mag) found in an early-type galaxy dominated by old stellar populations. We discuss possible origins for the observed hydrogen. Of the 75 SNe Ia for which we have so far obtained nebular spectra in 100IAS, no other SN shows a ${\\sim } 1000 \\, {\\rm km\\, s^{-1}}$ H α emission line with comparable line luminosity as ASASSN-18tb, emphasizing the rarity of such emission in the nebular phase. Based on preliminary results from our survey, the rate for ASASSN-18tb-like nebular H α emission could be as high as ${\\sim } 10{{\\ \\rm per\\ cent}}$ among sub-luminous SNe Ia.
Publisher: American Astronomical Society
Date: 20-12-1999
DOI: 10.1086/308108
Publisher: American Astronomical Society
Date: 17-04-2009
Publisher: American Astronomical Society
Date: 10-10-2000
DOI: 10.1086/312924
Publisher: Oxford University Press (OUP)
Date: 05-1982
Publisher: Oxford University Press (OUP)
Date: 07-1983
Publisher: American Astronomical Society
Date: 15-03-2017
Publisher: Oxford University Press (OUP)
Date: 06-08-2014
Publisher: American Astronomical Society
Date: 10-12-2013
Publisher: American Astronomical Society
Date: 09-1982
DOI: 10.1086/160234
Publisher: Oxford University Press (OUP)
Date: 04-03-2015
DOI: 10.1093/MNRAS/STV208
Publisher: American Astronomical Society
Date: 1994
DOI: 10.1086/191864
Publisher: American Astronomical Society
Date: 12-01-2007
Publisher: American Astronomical Society
Date: 07-2022
Abstract: Type Ia supernovae (SNe Ia) are more precise standardizable candles when measured in the near-infrared (NIR) than in the optical. With this motivation, from 2012 to 2017 we embarked on the RAISIN program with the Hubble Space Telescope (HST) to obtain rest-frame NIR light curves for a cosmologically distant s le of 37 SNe Ia (0.2 ≲ z ≲ 0.6) discovered by Pan-STARRS and the Dark Energy Survey. By comparing higher- z HST data with 42 SNe Ia at z 0.1 observed in the NIR by the Carnegie Supernova Project, we construct a Hubble diagram from NIR observations (with only time of maximum light and some selection cuts from optical photometry) to pursue a unique avenue to constrain the dark energy equation-of-state parameter, w . We analyze the dependence of the full set of Hubble residuals on the SN Ia host galaxy mass and find Hubble residual steps of size ∼0.06-0.1 mag with 1.5 σ −2.5 σ significance depending on the method and step location used. Combining our NIR s le with cosmic microwave background constraints, we find 1 + w = −0.17 ± 0.12 (statistical + systematic errors). The largest systematic errors are the redshift-dependent SN selection biases and the properties of the NIR mass step. We also use these data to measure H 0 = 75.9 ± 2.2 km s −1 Mpc −1 from stars with geometric distance calibration in the hosts of eight SNe Ia observed in the NIR versus H 0 = 71.2 ± 3.8 km s −1 Mpc −1 using an inverse distance ladder approach tied to Planck. Using optical data, we find 1 + w = −0.10 ± 0.09, and with optical and NIR data combined, we find 1 + w = −0.06 ± 0.07 these shifts of up to ∼0.11 in w could point to inconsistency in the optical versus NIR SN models. There will be many opportunities to improve this NIR measurement and better understand systematic uncertainties through larger low- z s les, new light-curve models, calibration improvements, and eventually by building high- z s les from the Roman Space Telescope.
Publisher: American Astronomical Society
Date: 1993
DOI: 10.1086/116427
Publisher: IOP Publishing
Date: 02-2012
DOI: 10.1086/664734
Publisher: American Astronomical Society
Date: 02-1989
DOI: 10.1086/167099
Publisher: American Astronomical Society
Date: 12-2000
DOI: 10.1086/316854
Publisher: American Astronomical Society
Date: 11-04-2016
Publisher: American Astronomical Society
Date: 12-1978
DOI: 10.1086/156656
Publisher: American Astronomical Society
Date: 1995
DOI: 10.1086/175151
Publisher: American Astronomical Society
Date: 20-01-2001
DOI: 10.1086/318363
Publisher: American Astronomical Society
Date: 08-1996
DOI: 10.1086/177570
Publisher: IOP Publishing
Date: 07-1994
DOI: 10.1086/133434
Publisher: American Astronomical Society
Date: 06-12-2012
Publisher: American Astronomical Society
Date: 22-07-2019
Publisher: IOP Publishing
Date: 27-11-2018
Publisher: Oxford University Press (OUP)
Date: 12-08-2015
Location: United States of America
Location: United States of America
No related grants have been discovered for Mark Phillips.