J/A+A/646/A22 SN 2020faa multiphotometry and spectra (Yang+, 2021)
Is supernova SN 2020faa an iPTF14hls look-alike?
Yang S., Sollerman J., Chen T.-W., Kool E.C., Lunnan R., Schulze S.,
Strotjohann N., Horesh A., Kasliwal M., Kupfer T., Mahabal A.A., Masci F.J.,
Nugent P., Perley D.A., Riddle R., Rusholme B., Sharma Y.
<Astron. Astrophys. 646, A22 (2021)>
=2021A&A...646A..22Y 2021A&A...646A..22Y (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, ugriz ; Optical ;
Photometry, ultraviolet ; Spectroscopy
Keywords: supernovae: general - supernovae: individual: SN 2020faa -
supernovae: individual: ZTF20aatqesi -
supernovae: individual: iPTF14hls
Abstract:
We present observations of SN 2020faa. This Type II supernova displays
a luminous lightcurve that started to rebrighten from an initial
decline. We investigate this in relation to the famous supernova
iPTF14hls, which received a great deal of attention and multiple
interpretations in the literature, but whose nature and source of
energy still remain unknown.
We demonstrate the great similarity between SN 2020faa and iPTF14hls
during the first 6 months, and use this comparison to forecast the
evolution of SN 2020faa and to reflect on the less well observed early
evolution of iPTF14hls.
We present and analyse our observational data, consisting mainly of
optical lightcurves from the Zwicky Transient Facility in the gri
bands and of a sequence of optical spectra. We construct colour curves
and a bolometric lightcurve, and we compare ejecta-velocity and
black-body radius evolutions for the two supernovae and for more
typical Type II supernovae.
The lightcurves show a great similarity with those of iPTF14hls over
the first 6 months in luminosity, timescale, and colour. In addition,
the spectral evolution of SN 2020faa is that of a Type II supernova,
although it probes earlier epochs than those available for iPTF14hls.
The similar lightcurve behaviour is suggestive of SN 2020faa being a
new iPTF14hls. We present these observations now to advocate follow-up
observations, since most of the more striking evolution of supernova
iPTF14hls came later, with lightcurve undulations and a spectacular
longevity. On the other hand, for SN 2020faa we have better
constraints on the explosion epoch than we had for iPTF14hls, and we
have been able to spectroscopically monitor it from earlier phases
than was done for the more famous sibling.
Description:
Photometric and spectroscopic data for SN 2020faa. Photometric data
includes ZTF gri data, as well as a few epochs of Swift UVOT
observations (without host subtracted). Spectra are all calibrated
with r band interpolated photometry. We've also uploaded spectra to
wiserep: https://wiserep.weizmann.ac.il/object/14519
Objects:
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RA (2000) DE Designation(s)
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14 47 09.47 +72 44 11.6 SN 2020faa = ZTF20aatqesi
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
phot.dat 66 1345 Photometry
spe1.dat 23 214 Spectrum taken by P60+SEDM on 2020-03-31
spe2.dat 23 432 Spectrum taken by LT+SPRAT on 2020-04-05
spe3.dat 23 214 Spectrum taken by P60+SEDM on 2020-06-01
spe4.dat 23 214 Spectrum taken by P60+SEDM on 2020-06-21
spe5.dat 23 1679 Spectrum taken by NOT+ALFOSC on 2020-07-02
spe6.dat 23 1549 Spectrum taken by NOT+ALFOSC on 2020-07-24
spe7.dat 23 214 Spectrum taken by P60+SEDM on 2020-07-26
spe8.dat 23 214 Spectrum taken by P60+SEDM on 2020-08-01
spe9.dat 23 214 Spectrum taken by P60+SEDM on 2020-08-11
spe10.dat 23 1704 Spectrum taken by NOT+ALFOSC on 2020-08-15
spe11.dat 23 214 Spectrum taken by P60+SEDM on 2020-08-21
spe12.dat 23 214 Spectrum taken by P60+SEDM on 2020-08-24
spe13.dat 23 1592 Spectrum taken by NOT+ALFOSC on 2020-08-30
spe14.dat 23 214 Spectrum taken by P60+SEDM on 2020-09-06
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Byte-by-byte Description of file: phot.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "date" Date Observation Date
13- 22 F10.2 d JD Julian Date
24 I1 --- Filter [1/9] Filter (1)
26- 31 F6.2 mag MAG ?=+99 Absolute magnitude in Filter (2)
33- 37 F5.2 mag mag ?=99 Apparent magnitude in Filter
39- 42 F4.2 mag e_mag ?=9.99 Magnitude Error
44- 48 F5.2 mag limmag ?=99 Limiting Magnitude in Filter
50- 59 A10 --- Instr Instrument
62- 66 A5 --- Issub If it's host subtracted magnitude
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Note (1): Filter code as follows:
1 = u band
2 = g band
3 = r band
4 = i band
5 = B band
6 = V band
7 = UVM2 band
8 = UVW1 band
9 = UVW2 band
Note (2): Measurements with magnitude of 99 stands for upper limits.
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Byte-by-byte Description of file: spe*.dat
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Bytes Format Units Label Explanations
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1- 6 F6.1 0.1nm lambda Wavelength
8- 23 E16.11 --- Flux Flux (1)
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Note (1): Fluxes are calibrated with ZTF r band interpolated photometry.
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Acknowledgements:
Sheng Yang, sheng.yang(at)astro.su.se
(End) Sheng Yang [OKC, Stockholm], Patricia Vannier [CDS] 27-Nov-2020