J/A+A/687/A108 Narrow absorption lines in SNe (Gonzalez-Gaitan+, 2024)
Narrow absorption lines from intervening material in supernovae.
I. Measurements and temporal evolution.
Gonzalez-Gaitan S., Gutierrez C.P., Anderson J.P., Morales-Garoffolo A.,
Galbany L., Goswami S., Mourao A.M., Mattila S., Sullivan M.
<Astron. Astrophys. 687, A108 (2024)>
=2024A&A...687A.108G 2024A&A...687A.108G (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Redshifts
Keywords: supernovae: general - dust, extinction - ISM: lines and bands
Abstract:
Narrow absorption features in nearby supernova (SN) spectra are a
powerful diagnostic of the slow-moving material in the line of sight:
they are extensively used to infer dust extinction from the host
galaxies, and they can also serve in the detection of circumstellar
material originating from the SN progenitor and present in the
vicinity of the explosion. Despite their wide use, very few studies
have examined the biases of the methods to characterize narrow lines,
and not many statistical analyses exist. This is the first paper of a
series in which we present a statistical analysis of narrow lines of
SN spectra of various resolutions. We develop a robust automated
methodology to measure the equivalent width (EW) and velocity of
narrow absorption lines from intervening material in the line of sight
of SNe, including NaI D, Ca II H&K, KI and diffuse interstellar bands
(DIBs). We carefully study systematic biases in heterogeneous spectra
from the literature by simulating different signal-to-noise, spectral
resolution, slit size and orientation and present the real
capabilities and limitations of using low- and mid-resolution spectra
to study these lines. In particular, we find that the measurement of
the equivalent width of the narrow lines in low-resolution spectra is
highly affected by the evolving broad P-Cygni profiles of the SN
ejecta, both for core-collapse and type Ia SNe, inducing a conspicuous
apparent evolution. Such pervading non-physical evolution of narrow
lines might lead to wrong conclusions on the line-of-sight material,
e.g. concerning circumstellar material ejected from the SN
progenitors. We present thus an easy way to detect and exclude those
cases to obtain more robust and reliable measurements. Finally, after
considering all possible effects, we analyse the temporal evolution of
the narrow features in a large sample of nearby SNe to detect any
possible variation in their EWs over time. We find no time evolution
of the narrow line features in our large sample for all SN types.
Description:
The data analysed in this paper consists of a large heterogeneous
sample from the literature obtained through large web compilations
such as SUSPECT (Richardson et al. 2001AAS...199.8408R 2001AAS...199.8408R), WISEREP1
(Yaron & Gal-Yam, 2012PASP..124..668Y 2012PASP..124..668Y), the Open Supernova Catalog
(Guillochon et al., 2017ApJ...835...64G 2017ApJ...835...64G), and from individual journal
publications.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled1.dat 209 1824 Sample of SNe initially included in our sample
refs.dat 232 274 References
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Name SN name
25- 34 A10 --- Type SN type
36- 41 A6 --- zsp Spectroscopic redshift
43- 47 A5 --- Nsp Number of spectra
49-209 A161 --- Refs References
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 56 A56 --- Ref Reference code
58- 76 A19 --- BibCode bibCode
78-232 A155 --- Com Comments
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History:
Santiago Gonzalez-Gaitan, gongsale(at)gmail.com
Acknowledgements:
We heartily thank all the research groups and observers for
making their data public. This research has made use of the Berkeley
SNDB database as well as the CfA Supernova Archive, which is funded in
part by the National Science Foundation through grant AST 0907903.
(End) Patricia Vannier [CDS] 28-Mar-2024