J/A+A/694/A11 SN 2020alm spectrum (Terwel+, 2025)
ZTF SN Ia DR2: Searching for late-time interaction signatures in
Type Ia supernovae from the Zwicky Transient Facility.
Terwel J.H., Maguire K., Dimitriadis G., Smith M., Reusch S., Lacroix L.,
Galbany L., Burgaz U., Harvey L., Schulze S., Rigault M., Groom S.L.,
Hale D., Kasliwal M.M., Kim Y.-L., Purdum J., Rusholme B., Sollerman J.,
Anderson J.P., Chen T.-W., Frohmaier C., Gromadzki M., Mueller-Bravo T.E.,
Nicholl M., Srivastav S., Deckers M.
<Astron. Astrophys. 694, A11 (2025)>
=2025A&A...694A..11T 2025A&A...694A..11T (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Spectra, optical
Keywords: circumstellar matter - supernovae: general -
supernovae: individual: SN 2018grt -
supernovae: individual: SN 2019ldf -
supernovae: individual: SN 2020tfc
Abstract:
The nature of the progenitor systems and explosion mechanisms that
give rise to Type Ia supernovae (SNe Ia) are still debated. The
interaction signature of circumstellar material (CSM) being swept up
by the expanding ejecta can constrain the type of system from which it
was ejected. However, most previous studies have focussed on finding
CSM ejected shortly before the SN Ia explosion, which still resides
close to the explosion site resulting in short delay times until the
interaction starts. We used a sample of 3627 SNe Ia from the Zwicky
Transient Facility (ZTF) that were discovered between 2018 and 2020
and searched for interaction signatures greater than 100 days after
peak brightness. By binning the late-time light curve data to push the
detection limit as deep as possible, we identified potential late-time
rebrightening in three SNe Ia (SN 2018grt, SN 2019dlf, and SN
2020tfc). The late-time optical detections occur between 550 and 1450d
after peak brightness, have mean absolute r-band magnitudes of -16.4
to -16.8mag, and last up to a few hundred days, which is significantly
brighter than the late-time CSM interaction discovered in the
prototype, SN 2015cp. The late-time detections in the three objects
all occur within 0.8kpc of the host nucleus and are not easily
explained by nuclear activity, another transient at a similar sky
position, or data quality issues. This is suggestive of environment or
specific progenitor characteristics playing a role in the production
of potential CSM signatures in these SNe Ia. Through simulating the
ZTF survey, we estimate that <0.5 per cent of normal SNe Ia display a
late-time (>100d post peak) strong H alpha-dominated CSM interaction.
This is equivalent to an absolute rate of 8+20-4 to 54+91-26
Gpc-3yr-1 assuming a constant SN Ia rate of
2.4*10-5Mpc-3yr-1 for z≤0.1. Weaker interaction signatures of
Halpha emission, more similar to the strength seen in SN 2015cp, could
be more common but are difficult to constrain with our survey depth.
Description:
Spectrum of SN 2020alm at MJD 60151.
Objects:
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RA (2000) DE Designation(s)
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16 52 01.5 +23 32 23 SN 2020alm
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
spectrum.dat 34 2024 Spectrum of SN 2020alm at MJD 60151
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See also:
J/A+A/694/A9 : Spectral Measurements of ZTF SN Ia DR2 (Burgaz+, 2025)
J/A+A/694/A10 : ZTF SN Ia DR2 (Dimitriadis+, 2025)
J/A+A/694/A12 : ZTF SN Ia DR2. secondary maximum in Type Ia SN (Deckers+, 2025)
Byte-by-byte Description of file: spectrum.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 0.1nm lambda Wavelength
13- 34 E22.16 10mW/m2/nm Flux Measured flux
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Acknowledgements:
Jacco H. Terwel, terwelj(at)tcd.ie
(End) Jacco H. Terwel [TCD, Dublin], Patricia Vannier [CDS] 07-Mar-2024