12 research outputs found
Ultraviolet Spectroscopy and TARDIS Models of the Broad-lined Type-Ic Supernova 2014ad
Few published ultraviolet (UV) spectra exist for stripped-envelope
supernovae, and none to date for broad-lined Type Ic supernovae (SN Ic-bl).
These objects have extremely high ejecta velocities and are the only supernova
type directly linked to gamma-ray bursts (GRBs). Here we present two epochs of
HST/STIS spectra of the SN Ic-bl 2014ad, the first UV spectra for this class.
We supplement this with 26 new epochs of ground-based optical spectra,
augmenting a rich spectral time series. The UV spectra do not show strong
features, likely due to high opacity, and are consistent with broadened
versions of other SN Ic spectra observed in the UV. We measure Fe II 5169
Angstrom velocities and show that SN 2014ad has even higher ejecta velocities
than most SNe Ic both with and without observed GRBs. We construct models of
the SN 2014ad UV+optical spectra using TARDIS, a 1D Monte-Carlo
radiative-transfer spectral synthesis code. The models fit the data well at
multiple epochs in the optical but underestimate the flux in the UV. We find
that high densities at high velocities are needed to reproduce the spectra,
with 3 M of material at 22,000 km s, assuming
spherical symmetry. Our nebular line fits suggest a steep density profile at
low velocities. Together, these results imply a higher total ejecta mass than
estimated from previous light curve analysis and expected from theory. This may
be reconciled by a flattening of the density profile at low velocity and extra
emission near the center of the ejecta.Comment: 25 pages, 14 figures, submitted to AAS Journal
SN 2019ewu: A Peculiar Supernova with Early Strong Carbon and Weak Oxygen Features from a New Sample of Young SN Ic Spectra
With the advent of high cadence, all-sky automated surveys, supernovae (SNe)
are now discovered closer than ever to their dates of explosion. However, young
pre-maximum light follow-up spectra of Type Ic supernovae (SNe Ic), probably
arising from the most stripped massive stars, remain rare despite their
importance. In this paper we present a set of 49 optical spectra observed with
the Las Cumbres Observatory through the Global Supernova Project for 6 SNe Ic,
including a total of 17 pre-maximum spectra, of which 8 are observed more than
a week before V-band maximum light. This dataset increases the total number of
publicly available pre-maximum light SN Ic spectra by 25% and we provide
publicly available SNID templates that will significantly aid in the fast
identification of young SNe Ic in the future. We present detailed analysis of
these spectra, including Fe II 5169 velocity measurements, O I 7774 line
strengths, and continuum shapes. We compare our results to published samples of
stripped supernovae in the literature and find one SN in our sample that stands
out. SN 2019ewu has a unique combination of features for a SN Ic: an extremely
blue continuum, high absorption velocities, a P-cygni shaped feature almost 2
weeks before maximum light that TARDIS radiative transfer modeling attributes
to C II rather than H, and weak or non-existent O I 7774 absorption
feature until maximum light.Comment: Submitted to the Astrophysical Journal. 15 pages, 6 figure
Over 500 Days in the Life of the Photosphere of the Type Iax Supernova SN 2014dt
Type Iax supernovae (SN Iax) are the largest known class of peculiar white
dwarf supernovae, distinct from normal Type Ia supernovae (SN Ia). The unique
properties of SN Iax, especially their strong photospheric lines out to
extremely late times, allow us to model their optical spectra and derive
physical parameters for the long-lasting photosphere. We present an extensive
spectral timeseries, including 21 new spectra, of SN Iax 2014dt from +11 to
+562 days after maximum light. We are able to reproduce the entire timeseries
with a self-consistent, nearly unaltered deflagration explosion model from Fink
et al. (2014) using TARDIS, an open-source radiative transfer code (Kerzendorf
& Sim 2014; Kerzendorf et al. 2023). We find that the photospheric velocity of
SN 2014dt slows its evolution between +64 and +148 days, which closely overlaps
the phase when we see SN 2014dt diverge from the normal spectral evolution of
SN Ia (+90 to +150 days). The photospheric velocity at these epochs,
~4001000 km s, may demarcate a boundary within the ejecta below which
the physics of SN Iax and normal SN Ia differ. Our results suggest that SN
2014dt is consistent with a weak deflagration explosion model that leaves
behind a bound remnant and drives an optically thick, quasi-steady-state wind
creating the photospheric lines at late times. The data also suggest that this
wind may weaken at epochs past +450 days, perhaps indicating a radioactive
power source that has decayed away.Comment: Accepted to ApJ, 22 pages, 8 figures, 3 table
Over 500 Days in the Life of the Photosphere of the Type Iax Supernova SN 2014dt
Type Iax supernovae (SNe Iax) are the largest known class of peculiar white dwarf SNe, distinct from normal Type Ia supernovae (SNe Ia). The unique properties of SNe Iax, especially their strong photospheric lines out to extremely late times, allow us to model their optical spectra and derive the physical parameters of the long-lasting photosphere. We present an extensive spectral timeseries, including 21 new spectra, of SN Iax 2014dt from +11 to +562 days after maximum light. We are able to reproduce the entire timeseries with a self-consistent, nearly unaltered deflagration explosion model from Fink et al. using TARDIS , an open source radiative-transfer code. We find that the photospheric velocity of SN 2014dt slows its evolution between +64 and +148 days, which closely overlaps the phase when we see SN 2014dt diverge from the normal spectral evolution of SNe Ia (+90 to +150 days). The photospheric velocity at these epochs, ∼400–1000 km s ^−1 , may demarcate a boundary within the ejecta below which the physics of SNe Iax and normal SNe Ia differ. Our results suggest that SN 2014dt is consistent with a weak deflagration explosion model that leaves behind a bound remnant and drives an optically thick, quasi-steady-state wind creating the photospheric lines at late times. The data also suggest that this wind may weaken at epochs past +450 days, perhaps indicating a radioactive power source that has decayed away
StaNdaRT: a repository of standardised test models and outputs for supernova radiative transfer
StaNdaRT: A repository of standardized test models and outputs for supernova radiative transfer
Accepted for publication in A&A. 26 pages, 12 figures. The ejecta models and output files from the simulations are available at https://github.com/sn-rad-trans/data1International audienceWe present the first results of a comprehensive supernova (SN) radiative-transfer (RT) code-comparison initiative (StaNdaRT), where the emission from the same set of standardized test models is simulated by currently-used RT codes. A total of ten codes have been run on a set of four benchmark ejecta models of Type Ia supernovae. We consider two sub-Chandrasekhar-mass ( M) toy models with analytic density and composition profiles and two Chandrasekhar-mass delayed-detonation models that are outcomes of hydrodynamical simulations. We adopt spherical symmetry for all four models. The results of the different codes, including the light curves, spectra, and the evolution of several physical properties as a function of radius and time, are provided in electronic form in a standard format via a public repository. We also include the detailed test model profiles and several python scripts for accessing and presenting the input and output files. We also provide the code used to generate the toy models studied here. In this paper, we describe in detail the test models, radiative-transfer codes and output formats and provide access to the repository. We present example results of several key diagnostic features
StaNdaRT: A repository of standardized test models and outputs for supernova radiative transfer
Accepted for publication in A&A. 26 pages, 12 figures. The ejecta models and output files from the simulations are available at https://github.com/sn-rad-trans/data1International audienceWe present the first results of a comprehensive supernova (SN) radiative-transfer (RT) code-comparison initiative (StaNdaRT), where the emission from the same set of standardized test models is simulated by currently-used RT codes. A total of ten codes have been run on a set of four benchmark ejecta models of Type Ia supernovae. We consider two sub-Chandrasekhar-mass ( M) toy models with analytic density and composition profiles and two Chandrasekhar-mass delayed-detonation models that are outcomes of hydrodynamical simulations. We adopt spherical symmetry for all four models. The results of the different codes, including the light curves, spectra, and the evolution of several physical properties as a function of radius and time, are provided in electronic form in a standard format via a public repository. We also include the detailed test model profiles and several python scripts for accessing and presenting the input and output files. We also provide the code used to generate the toy models studied here. In this paper, we describe in detail the test models, radiative-transfer codes and output formats and provide access to the repository. We present example results of several key diagnostic features
StaNdaRT: A repository of standardized test models and outputs for supernova radiative transfer
Accepted for publication in A&A. 26 pages, 12 figures. The ejecta models and output files from the simulations are available at https://github.com/sn-rad-trans/data1International audienceWe present the first results of a comprehensive supernova (SN) radiative-transfer (RT) code-comparison initiative (StaNdaRT), where the emission from the same set of standardized test models is simulated by currently-used RT codes. A total of ten codes have been run on a set of four benchmark ejecta models of Type Ia supernovae. We consider two sub-Chandrasekhar-mass ( M) toy models with analytic density and composition profiles and two Chandrasekhar-mass delayed-detonation models that are outcomes of hydrodynamical simulations. We adopt spherical symmetry for all four models. The results of the different codes, including the light curves, spectra, and the evolution of several physical properties as a function of radius and time, are provided in electronic form in a standard format via a public repository. We also include the detailed test model profiles and several python scripts for accessing and presenting the input and output files. We also provide the code used to generate the toy models studied here. In this paper, we describe in detail the test models, radiative-transfer codes and output formats and provide access to the repository. We present example results of several key diagnostic features
StaNdaRT: a repository of standardised test models and outputs for supernova radiative transfer
International audienceWe present the first results of a comprehensive supernova (SN) radiative-transfer (RT) code-comparison initiative (StaNdaRT), where the emission from the same set of standardised test models is simulated by currently used RT codes. We ran a total of ten codes on a set of four benchmark ejecta models of Type Ia SNe. We consider two sub-Chandrasekhar-mass (Mtot = 1.0 M⊙) toy models with analytic density and composition profiles and two Chandrasekhar-mass delayed-detonation models that are outcomes of hydrodynamical simulations. We adopt spherical symmetry for all four models. The results of the different codes, including the light curves, spectra, and the evolution of several physical properties as a function of radius and time are provided in electronic form in a standard format via a public repository. We also include the detailed test model profiles and several Python scripts for accessing and presenting the input and output files. We also provide the code used to generate the toy models studied here. In this paper, we describe the test models, radiative-transfer codes, and output formats in detail, and provide access to the repository. We present example results of several key diagnostic features
tardis-sn/tardis: TARDIS v2023.11.05
<p>This release has been created automatically by the TARDIS continuous delivery pipeline.</p>
<p>A complete list of changes for this release is available at <a href="https://github.com/tardis-sn/tardis/blob/master/CHANGELOG.md">CHANGELOG.md</a>.</p>