J/ApJ/951/67 Opt. spectra of type Iax SN 2014dt over 500d (Camacho-Neves+, 2023)
Over 500 days in the life of the photosphere of the Type Iax supernova SN2014dt.
Camacho-Neves Y., Jha S.W., Barna B., Dai M., Filippenko A.V., Foley R.J.,
Hosseinzadeh G., Howell D.A., Johansson J., Kelly P.L., Kerzendorf W.E.,
Kwok L.A., Larison C., Magee M.R., McCully C., O'Brien J.T., Pan Y.-C.,
Pandya V., Singhal J., Stahl B.E., Szalai T., Wieber M., Williamson M.
<Astrophys. J., 951, 67 (2023)>
=2023ApJ...951...67C 2023ApJ...951...67C
ADC_Keywords: Supernovae; Spectra, optical
Keywords: Supernovae ; Type Ia supernovae ; Radiative transfer ;
Radiative transfer simulations ; Supernova dynamics
Abstract:
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,
∼400-1000km/s, 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 +450d,
perhaps indicating a radioactive power source that has decayed away.
Description:
SN 2014dt was discovered at 13.6mag on 2014 October 29.8 (UT) in the
nearby galaxy M61 (d∼14.6Mpc).
In this paper, we adopt the Bmax date from
Kawabata+ (2018PASJ...70..111K 2018PASJ...70..111K), 2014 Oct 20.4 (JD=2456950.9±4.0d),
which is consistent with other measurements.
We present 21 new spectra of SN 2014dt, ranging from +32 to +456 days
past Bmax.
Eleven new spectra of SN 2014dt were taken using the Robert Stobie
Spectrograph (RSS) on the 10m Southern African Large Telescope (SALT).
Four new spectra of SN 2014dt were taken with the DEep Imaging
Multi-Object Spectrograph (DEIMOS) on the 10m Keck II telescope at the
W. M. Keck Observatory.
Four new spectra of SN 2014dt were taken with FLOYDS, a pair of nearly
identical, low-resolution spectrographs installed on the 2m Faulkes
Telescope North (FTN) at Haleakal Observatory and Faulkes Telescope
South (FTS) at Siding Spring Observatory; both telescopes are part of
the Las Cumbres Observatory Global Telescope Network.
One new spectrum taken with the Gemini Multi-Object Spectrograph
(GMOS) on the 8.1m Gemini-North telescope is a combination of eight
exposures from two consecutive nights.
One new spectrum was taken with the Goodman High Throughput
Spectrograph (GHTS) on the 4m Southern Astrophysical Research
Telescope (SOAR) on 2015 April 10.
We also collect published optical spectra of SN 2014dt, ranging from
+11 to +562d past Bmax from the literature, see Section 2.
In total, we present 69 new and previously published SN 2014dt spectra.
Objects:
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RA (ICRS) DE Designation(s)
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12 21 57.60 +04 28 18.4 SN 2014dt = SPIRITS15sd
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 115 69 Spectral observations of SN 2014dt
table3.dat 39 69 *TARDIS parameters
fig1/* . 69 *Individual spectra of SN 2014dt in MRT format
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Note on table3.dat: We use TARDIS (Kerzendorf & Sim 2014MNRAS.440..387K 2014MNRAS.440..387K;
Kerzendorf+ 2023, doi.org/10.5281/zenodo.7525913), a 1D open source
Monte Carlo (MC) radiative-transfer code to model the spectra of SN2014dt.
Note on fig1/*: Each spectrum is post manual cleaning and
scaling/mangling, but it is WITHOUT the Galactic extinction and
host-galaxy redshift correction.
These files can be read in python using the astropy package:
from astropy.table import Table
data = Table.read("2016-05-07561.68Keck_mangled.mrt", format="ascii.cds")
or with the most recent version of TOPCAT (> Version 4.8)
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See also:
B/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)
B/gemini : The Gemini Observation Log (CADC, 2001-)
J/MNRAS/425/1789 : Berkeley supernova Ia program. I. (Silverman+, 2012)
J/MNRAS/440/696 : HI absorption in nearby radio galaxies (Allison+, 2014)
J/MNRAS/438/L101 : First month on SN 2013ej (Valenti+, 2014)
J/AJ/148/1 : Optical and ultraviolet phot. of SN 2012fr (Zhang+, 2014)
J/MNRAS/454/3816 : Cobalt emission in nebular phase spectra (Childress+, 2015)
J/MNRAS/451/1973 : Type Ia supernovae high-velocity features (Silverman+, 2015)
J/MNRAS/484/3785 : Relative specific Type Ia supernovae rate (Brown+, 2019)
J/ApJ/886/40 : Luminous SPIRITS IR transients follow-up (Jencson+, 2019)
J/ApJS/241/38 : A comprehensive analysis of Spitzer SNe (Szalai+, 2019)
J/MNRAS/492/4325 : BSNIP Spectroscopy of 247 type Ia supernovae (Stahl+, 2020)
J/ApJ/921/L6 : Opt. phot. & sp. for SN 2021fcg (Karambelkar+, 2021)
J/ApJ/925/217 : Opt. phot. and sp. monitoring of SN 2020sck (Dutta+, 2022)
J/A+A/687/A108 : Narrow absorption lines in SNe (Gonzalez-Gaitan+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 d Phase [11/562] Days since B maximum (G1)
6- 15 A10 "Y/M/D" Date Observation Date, UT
17- 24 F8.2 d MJD [56961.2/57515] Modified Julian Date of
observation (JD-2400000.5)
26- 40 A15 --- Inst Telescope+Instrument used
42- 45 I4 s ExpMin [300/7200] Exposure time, total or minimum
47- 50 I4 s ExpMax [1200/1800]? Exposure time, maximum
52- 55 I4 --- RMin [300/2000] Spectral resolution (or minimum),
λ/δλ
57- 60 I4 --- RMax [600/4000]? Spectral resolution, maximum,
λ/δλ
62- 65 A4 --- Filt Filter(s) used to scale or mangle spectrum
67- 69 A3 --- Ref Reference(s) (1)
71-108 A38 --- File Name of the ASCII file in subdirectory "fig1";
column added by CDS
110-115 F6.2 d Phase2 [10.7/561.7] Phase as given in spectrum
file IDs; column added by CDS
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Note (1): References as follows:
0 = this paper;
1 = Foley et al. 2016MNRAS.461..433F 2016MNRAS.461..433F
2 = Foley et al. 2015ApJ...798L..37F 2015ApJ...798L..37F
3 = Ochner et al. 2014ATel.6648....1O 2014ATel.6648....1O
4 = Stahl et al. 2020, J/MNRAS/492/4325
5 = Kawabata et al. 2018PASJ...70..111K 2018PASJ...70..111K
6 = Singh et al. 2018MNRAS.474.2551S 2018MNRAS.474.2551S
7 = Lyman et al. 2018MNRAS.473.1359L 2018MNRAS.473.1359L
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 d Phase [11/562] Days since B maximum (G1)
6- 10 F5.1 d texp [21.7/572.7] Time since explosion
12- 19 E8.2 Lsun Lreq [396000/165000000] Luminosity requested
21- 24 I4 0.1nm LwaveMin [3684/6469] Luminosity requested wavelength
minimum, Angstroms
26- 29 I4 0.1nm LwaveMax [5965/9448] Luminosity requested wavelength
maximum, Angstroms
31- 34 I4 km/s vouter [4478/7513] Outer boundary of line-forming
region
36- 39 I4 km/s vphot [42/4800] Photospheric velocity
(inner boundary)
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Global notes:
Note (G1): Days since B maximum, UT 2014 October 20.4 (MJD56950.4),
corrected for time dilation.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Aug-2025