J/A+A/694/A9 Spectral Measurements of ZTF SN Ia DR2 (Burgaz+, 2025)
ZTF SN Ia DR2:
The spectral diversity of Type Ia supernovae in a volume-limited sample.
Burgaz U., Maguire K., Dimitriadis G., Harvey L., Senzel R., Sollerman J.,
Nordin J., Galbany L., Rigault M., Smith M., Goobar A., Johansson J.,
Rosnet P., Alburai A., Amenouche M., Deckers M., Dhawan S., Ginolin M.,
Kim Y.-L., Miller A.A., Muller-Bravo T.E., Nugent P.E., Terwel J.H.,
Dekany R., Drake A., Graham M.J., Groom S.L., Kasliwal M.M., Kulkarni S.R.,
Nolan K., Nir G., Riddle R.L., Rusholme B., Sharma Y.
<Astron. Astrophys. 694, A9 (2025)>
=2025A&A...694A...9B 2025A&A...694A...9B (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Spectroscopy ; Equivalent widths ; Optical
Keywords: supernovae: general
Abstract:
More than 3000 spectroscopically confirmed Type Ia supernovae (SNe Ia)
are presented in the Zwicky Transient Facility SN Ia Data Release 2
(ZTF DR2). In this paper, we detail the spectral properties of 482 SNe
Ia near maximum light, up to a redshift limit of z<0.06. We measure
the velocities and pseudo-equivalent widths (pEW) of key spectral
features (SiII 5972 and SiII 6355) and investigate the relation
between the properties of the spectral features and the photometric
properties from the SALT2 light-curve parameters as a function of
spectroscopic sub-class. We discuss the non-negligible impact of host
galaxy contamination on SN Ia spectral classifications, as well as
investigate the accuracy of spectral template matching of the ZTF DR2
sample. We define a new subclass of underluminous SNe Ia ('04gs-like')
that lie spectroscopically between normal SNe Ia and transitional
86G-like SNe Ia (stronger SiII 5972 than normal SNe Ia but
significantly weaker TiII features than '86G-like' SNe). We model
these '04gs-like' SN Ia spectra using the radiative-transfer spectral
synthesis code tardis and show that cooler temperatures alone are
unable to explain their spectra; some changes in elemental abundances
are also required. However, the broad continuity in spectral
properties seen from bright ('91T-like') to faint normal SN Ia,
including the transitional and 91bg-like SNe Ia, suggests that
variations within a single explosion model may be able to explain
their behaviour.
Description:
This dataset includes measurements of velocity and pseudo-equivalent
widths (pEW) of the 6355 and 5972 Angstrom lines for supernovae
detected in ZTF DR2. It contains data for 482 spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1h.dat 111 392 Measurements for d_DLR > 0.2
tablea1s.dat 111 90 Measurements for d_DLR < 0.2
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See also:
J/A+A/694/A10 : ZTF SN Ia DR2 (Dimitriadis+, 2025)
J/A+A/694/A11 : SN 2020alm spectrum (Terwel+, 2025)
J/A+A/694/A12 : ZTF SN Ia DR2. secondary maximum in Type Ia SN (Deckers+, 2025)
Byte-by-byte Description of file: tablea1h.dat tablea1s.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- ZTF ZTF name
14- 21 A8 --- SN IAU name
23- 26 F4.1 --- Phase Phase
28- 37 A10 --- Subtype Sub-type
39- 42 A4 --- WangType Wang-type
44- 45 A2 --- BranchType Branch-type
47- 50 F4.2 10+4km/s vsi6355 SiII 6355 Velocity
52- 55 F4.2 10+4km/s e_vsi6355 SiII 6355 Vel lower uncertainty
57- 60 F4.2 10+4km/s E_vsi6355 SiII 6355 Vel upper uncertainty
62- 67 F6.2 0.1nm pEW6355 SiII 6355 pEW
69- 73 F5.2 0.1nm e_pEW6355 SiII 6355 pEW lower uncertainty
75- 79 F5.2 0.1nm E_pEW6355 SiII 6355 pEW higher uncertainty
81- 84 F4.2 10+4km/s vsi5972 ?=- SiII 5972 Velocity
86- 89 F4.2 10+4km/s e_vsi5972 ?=- SiII 5972 Vel lower uncertainty
91- 94 F4.2 10+4km/s E_vsi5972 ?=- SiII 5972 Vel upper uncertainty
96-100 F5.2 0.1nm pEW5972 SiII 5972 pEW
101 A1 --- l_pEW5972 [*] * for upper limit of pEW5972
103-106 F4.2 0.1nm e_pEW5972 ?=- SiII 5972 pEW lower uncertainty
108-111 F4.2 0.1nm E_pEW5972 ?=- SiII 5972 pEW higher uncertainty
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Acknowledgements:
Umut Burgaz, burgazu(at)tcd.ie
(End) Patricia Vannier [CDS] 26-Nov-2024