J/A+A/652/A136 SN 2020bqj light curves (Kool+, 2021)
SN 2020bqj: A Type Ibn supernova with a long lasting peak plateau.
Kool E., Karamehmetoglu E., Sollerman J., Schulze S., Lunnan R.,
Reynolds T.M., Barbarino C., Bellm E.C., De K., Duev D.A., Fremling C.,
Golkhou V.Z., Graham M.L., Green D.A., Horesh A., Kaye S., Kim Y.-L.,
Laher R.R., Masci F.J., Nordin J., Perley D.A., Phinney E.S., Porter M.,
Reiley D., Rodriguez H., van Roestel J., Rusholme B., Sharma Y., Sfaradi I.,
Soumagnac M.T., Taggart K., Tartaglia L., Williams D.R.A., Yan L.
<Astron. Astrophys. 652, A136 (2021)>
=2021A&A...652A.136K 2021A&A...652A.136K (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, ultraviolet ; Optical
Keywords: supernovae: general - supernovae: individual: SN 2020bqj -
supernovae: individual: SN 2011hw
Abstract:
Type Ibn supernovae are a rare class of stripped envelope supernovae
interacting with a helium-rich CSM. The majority of the SNe Ibn
reported display a surprising homogeneity in their fast lightcurves
and starforming hosts.
We present the discovery and study of SN 2020bqj (ZTF20aalrqbu), a SN
Ibn with a long-duration peak plateau lasting 40 days and hosted by a
faint low-mass galaxy. We aim to explain its peculiar properties using
an extensive data set.
We compare the evolution of SN 2020bqj with SNe Ibn from the
literature. We fit the bolometric and multi-band lightcurves with
different powering mechanism models.
The risetime, peak magnitude and spectral features of SN 2020bqj are
consistent with those of most SNe Ibn, but the SN is a clear outlier
based on its bright, long-lasting peak plateau and low host mass. We
show through modeling that the lightcurve can be powered predominantly
by shock heating from the interaction of the SN ejecta and a dense
CSM. The peculiar Type Ibn SN 2011hw is a close analog to SN 2020bqj,
suggesting a similar progenitor and CSM scenario. In this scenario a
very massive progenitor star in the transitional phase between a
luminous blue variable and a compact Wolf-Rayet star undergoes
core-collapse, embedded in a dense helium-rich CSM with an elevated
opacity compared to normal SNe Ibn, due to the presence of residual
hydrogen. This scenario is consistent with the observed properties of
SN 2020bqj and the modeling results.
SN 2020bqj is a compelling example of a transitional SN Ibn/IIn based
on not only its spectral features, but also its lightcurve, host
galaxy properties and the inferred progenitor properties. The strong
similarity with SN 2011hw suggests this subclass may be the result of
a progenitor in a stellar evolution phase that is distinct from those
of progenitors of regular SNe Ibn.
Description:
Optical and UV photometry of SN 2020bqj.
Optical photometry was obtained with the ZTF camera mounted on the P48
telescope from nominal ZTF survey observations: the public Northern
Sky Survey with a 3-day cadence in g- and r-band and the ZTF Uniform
Depth Survey (ZUDS) at a nightly cadence in g-, r- and i-band from
MJD 58954 onwards.
Follow-up in the ultraviolet (UV), starting at +41 days, was obtained
with the UltraViolet and Optical Telescope (UVOT) aboard the Neil
Gehrels Swift Observatory in the UVW2, UVM2 and UVW1 filters.
Simultaneously, optical follow-up was obtained in the u, B and
V-filters.
Objects:
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RA (2000) DE Designation(s)
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15 33 40.48 +34 28 44.3 SN 2020bqj
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
photom.dat 52 501 SN 2020bqj photometry
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 8 F8.2 d MJD Modified Julian Day
10- 14 F5.1 d Phase Restframe days since explosion epoch MJD=58880
16- 19 A4 --- Filter Filter used (1)
22- 26 F5.2 mag mag ?=99 Observed AB magnitude in Filter
29- 33 F5.2 mag e_mag ?=99 Magnitude error
36- 40 F5.2 mag limmag ?=99 Limiting magnitude observation
43- 52 A10 --- Instr Telescope and instrument
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Note (1): Filter are u, g, r, i, z, UVW1, UVM2, UVW2, B, V.
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Acknowledgements:
Erik Kool, erik.kool(at)astro.su.se
(End) Patricia Vannier [CDS] 27-May-2021