J/A+A/683/A223 1100 days in the life of SN 2018ibb (Schulze+, 2024)
1100 days in the life of the supernova 2018ibb.
The best pair-instability supernova candidate, to date.
Schulze S., Fransson C., Kozyreva A., Chen T.-W., Yaron O., Jerkstrand A.,
Gal-Yam A., Sollerman J., Yan L., Kangas T., Leloudas G., Omand C.M.B.,
Smartt S.J., Yang Y., Nicholl M., Sarin N., Yao Y., Brink T.G., Sharon A.,
Rossi A., Chen P., Chen Z., Cikota A., De K., Drake A.J., Filippenko A.V.,
Fremling C., Freour L., Fynbo J.P.U., Ho A.Y.Q., Inserra C., Irani I.,
Kuncarayakti H., Lunnan R., Mazzali P., Ofek E.O., Palazzi E., Perley D.A.,
Pursiainen M., Rothberg B., Shingles L.J., Smith K., Taggart K.,
Tartaglia L., Zheng W., Anderson J.P., Cassara L., Christensen E.,
Djorgovski S.G., Galbany L., Gkini A., Graham M.J., Gromadzki M.,
Groom S.L., Hiramatsu D., Howell D.A., Kasliwal M.M., McCully C.,
Mueller-Bravo T.E., Paiano S., Paraskeva E., Pessi P.J., Polishook D.,
Rau A., Rigault M., Rusholme B.
<Astron. Astrophys. 683, A223 (2024)>
=2024A&A...683A.223S 2024A&A...683A.223S (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, UBVRIJKLMNH ; Photometry, ultraviolet
Keywords: supernovae: individual: SN 2018ibb -
supernovae: individual: ATLAS18unu -
supernovae: individual: ZTF18acenqto
Abstract:
Stars with zero-age main sequence masses between 140 and 260 solar
masses are thought to explode as pair-instability supernovae (PISNe).
During their thermonuclear runaway, PISNe can produce up to several
tens of solar masses of radioactive nickel, resulting in luminous
transients similar to some superluminous supernovae (SLSNe). Yet, no
unambiguous PISN has been discovered so far. SN 2018ibb is a
hydrogen-poor SLSN at z=0.166 that evolves extremely slowly compared
to the hundreds of known SLSNe. Between mid 2018 and early 2022, we
monitored its photometric and spectroscopic evolution from the UV to
the near-infrared (NIR) with 2-10m class telescopes. SN 2018ibb
radiated >3*1051erg during its evolution, and its bolometric light
curve reached >2*1044erg/s at its peak. The long-lasting rise of >93
rest-frame days implies a long diffusion time, which requires a very
high total ejected mass. The PISN mechanism naturally provides both
the energy source (Ni-56) and the long diffusion time. Theoretical
models of PISNe make clear predictions as to their photometric and
spectroscopic properties. SN 2018ibb complies with most tests on the
light curves, nebular spectra and host galaxy, and potentially all
tests with the interpretation we propose. Both the light curve and the
spectra require 25-44 solar masses of freshly nucleosynthesised Ni-56,
pointing to the explosion of a metal-poor star with a helium core mass
of 120-130 solar masses at the time of death. This interpretation is
also supported by the tentative detection of [CoII]-1.025um, which has
never been observed in any other PISN candidate or SLSN before. We
observe a significant excess in the blue part of the optical spectrum
during the nebular phase, which is in tension with predictions of
existing PISN models. However, we have compelling observational
evidence for an eruptive mass-loss episode of the progenitor of SN
2018ibb shortly before the explosion, and our dataset reveals that the
interaction of the SN ejecta with this oxygen-rich circumstellar
material contributed to the observed emission. That may explain this
specific discrepancy with PISN models. Powering by a central engine,
such as a magnetar or a black hole, can be excluded with high
confidence. This makes SN 2018ibb by far the best candidate for being
a PISN, to date.
Description:
Multi-band and bolometric light curves of SN 2018ibb, as well as a
tabulated version of the evolution of the blackbody radius and
temperature. The photometry and the spectra of SN 2018ibb are also
available on WISeREP (https://www.wiserep.org/object/10471).
Objects:
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RA (2000) DE Designation(s)
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04 38 56.950 -20 39 44.10 SN 2018ibb = Gaia 19cvo
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 45 1013 Multi-band photometry
tablec1.dat 48 588 Bolometric light curve and blackbody properties
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See also:
https://www.wiserep.org/object/10471 : SN 2018ibb Home Page
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Tel/Inst Name of telescope and instrument
17- 24 A8 --- Filter Filter name
26- 34 F9.3 d MJD Modified Julian Date
36- 40 F5.2 mag mag Apparent magnitude in Filter (1)
42- 45 F4.2 mag e_mag 1-sigma error on apparent magnitude
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Note (1): All measurements are in the AB system, host-subtracted but not
corrected for extinction.
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 6 F6.1 d Phase Rest-frame days since peak
8- 12 F5.2 [10-7W] logLbol ?=- Bolometric luminosity (scale: log10)
14- 17 F4.2 [10-7W] E_logLbol ?=- Upper 1-sigma error on
bolometric luminosity
19- 22 F4.2 [10-7W] e_logLbol ?=- Lower 1-sigma error on
bolometric luminosity
24- 28 A5 [cm] logR ?=- Blackbody radius (scale: log10) (1)
30- 33 A4 [cm] E_logR ?=- Upper 1-sigma error on logR
35- 38 A4 [cm] e_logR ?=- Lower 1-sigma error on logR
40- 44 A5 K T ?=- Blackbody temperature (2)
46- 48 A3 K e_T ?=- 1-sigma error on blackbody temperature
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Note (1): The blackbody radius is only reported where the spectrum is a
blackbody and sufficient multi-band data are available to constrain the
blackbody spectrum.
Note (2): The blackbody temperature is only reported where the spectrum is a
blackbody and sufficient multi-band data are available to constrain the
blackbody spectrum.
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Acknowledgements:
Steve Schulze, steve.schulze(at)fysik.su.se
(End) Steve Schulze [Stockholm University], Patricia Vannier [CDS] 17-Dec-2023