J/ApJ/922/186 Keck/NIRES spectrum of type Ia SN 2020qxp (Hoeflich+, 2021)
Measuring an off-center detonation through infrared line profiles: the peculiar
Type Ia supernova SN 2020qxp/ASASSN-20jq.
Hoeflich P., Ashall C., Bose S., Baron E., Stritzinger M.D., Davis S.,
Shahbandeh M., Anand G.S., Baade D., Burns C.R., Collins D.C.,
Diamond T.R., Fisher A., Galbany L., Hristov B.A., Hsiao E.Y.,
Phillips M.M., Shappee B., Suntzeff N.B., Tucker M.
<Astrophys. J., 922, 186-186 (2021)>
=2021ApJ...922..186H 2021ApJ...922..186H (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae; Spectra, infrared
Keywords: Type Ia supernovae
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 [FeII] at 1.644µm, which is highly asymmetric with a
tilted top and a peak redshifted by ∼2000km/s. In comparison with 2D
non-LTE synthetic spectra computed from 3D simulations of off-center
delayed-detonation Chandrasekhar-mass (Mch) 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 [FeII]1.644µm
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
∼4x109g/cm3. We also tentatively identify a stable Ni feature
around 1.9µm 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
∼0.3MWD 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 56Ni in physical space. This results in the formation of a
prevalent [CaII]0.73µm 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-MCh 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).
Description:
SN 2020qxp/ASASSN-20jq was discovered by the All-Sky Automated Survey
for Supernovae (ASASSN, Kochanek+ 2017PASP..129j4502K 2017PASP..129j4502K) on
2020-August-8.13 UT in the outskirts of the SBm galaxy NGC 5002.
Our medium-resolution nebular NIR spectrum of SN 2020qxp/ASASSN-20jq
was obtained with the Keck II telescope equipped with the
Near-Infrared Echellette Spectrometer (NIRES) on 2021 March 04.5 UT
(i.e., MJD=59277.50). This is +191 rest-frame days (d) past the
epoch of B-band maximum (tB). The mean resolution of the spectrum is
R∼2700, and the spectral range extends between 0.96 and 2.46um.
Objects:
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RA (ICRS) DE Designation(s)
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13 10 37.83 +36 37 43.7 SN 2020qxp = ASASSN -20jq
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 39 6946 Keck/NIRES near-IR spectrum of peculiar type Ia
SN2020qxp/ASASSN-20jq taken at +191d past the epoch
of rest-frame B-band maximum (MJD=59277.50)
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Description of file:
SN2020qxpNIRES20210304.fits is the spectrum in FITS format.
See also:
J/A+AS/97/443 : Fluorescence for Be to Zn (Kaastra+ 1993)
J/other/Sci/340.170 : Classifications of 188 SNe Ia (Wang+, 2013)
J/ApJ/773/53 : Type Ia SNe spectroscopy by the CSP (Folatelli+, 2013)
J/A+A/561/A146 : SN 2010ae optical spectra (Stritzinger+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/A+A/573/A2 : SN 2012Z spectra (Stritzinger+, 2015)
J/ApJS/217/27 : Morphologies of z<0.01 SDSS-DR7 galaxies (Ann+, 2015)
J/MNRAS/448/2766 : Strong lines in the opt/NIR for SN 2002bo (Blondin+, 2015)
J/ApJ/841/48 : UBVR and IR photometry of SN 2011fe (Ia) (Shappee+, 2017)
J/A+A/611/A58 : SN 2007on and SN 2011iv light curves (Gall+, 2018)
J/ApJ/869/56 : Updated calibration of the CSP-I SNe Ia sample (Burns+, 2018)
J/MNRAS/483/628 : SN Ia properties using bolometric LCs (Scalzo+, 2019)
J/A+A/630/A76 : SN2016hnk photometry and spectroscopy (Galbany+, 2019)
J/ApJ/895/118 : Optical and NIR photometry of 2 Ia type SNe (Burns+, 2020)
J/ApJ/896/165 : Optical light curves of SN 2016hnk (Jacobson-Galan+, 2020)
J/ApJ/902/46 : LCO network light curves of SN Ia 2018gv (Yang+, 2020)
J/ApJ/902/145 : Cosmicflows-4: Tully-Fisher distances (Kourkchi+, 2020)
J/A+A/649/A155 : Impact of core and shell masses on SNe Ia (Gronow+, 2021)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.8 um lambda [0.96/2.47] Spectrum wavelength
12- 25 E14.9 cW/m2/nm S [-2.4e-17/2.5e-17] Flux density,
in erg/s/cm2/Å
27- 39 E13.8 cW/m2/nm e_S [1.3e-20/6e-18] Uncertainty in Flux density
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Mar-2023