J/ApJ/913/143 Optical light curves of the type Ic SN 2019stc (Gomez+, 2021)
The luminous and double-peaked type Ic supernova 2019stc: evidence for multiple
energy sources.
Gomez S., Berger E., Hosseinzadeh G., Blanchard P.K., Nicholl M.,
Villar V.A.
<Astrophys. J., 913, 143 (2021)>
=2021ApJ...913..143G 2021ApJ...913..143G
ADC_Keywords: Supernovae; Photometry, ugriz
Keywords: Supernovae ; Type Ic supernovae
Abstract:
We present optical photometry and spectroscopy of SN 2019stc
(=ZTF19acbonaa), an unusual Type Ic supernova (SN Ic) at a redshift of
z=0.117. SN 2019stc exhibits a broad double-peaked light curve, with
the first peak having an absolute magnitude of Mr=-20.0mag, and the
second peak, about 80 rest-frame days later, Mr=-19.2mag. The total
radiated energy is large, Erad∼2.5x1050erg. Despite its large
luminosity, approaching those of Type I superluminous supernovae
(SLSNe), SN 2019stc exhibits a typical SN Ic spectrum, bridging the
gap between SLSNe and SNe Ic. The spectra indicate the presence of
Fe-peak elements, but modeling of the first light-curve peak with
radioactive heating alone leads to an unusually high nickel mass
fraction of fNi∼0.31 (MNi∼3.2M☉). Instead, if we model the
first peak with a combined magnetar spin-down and radioactive heating
model we find a better match with Mej∼4M☉, a magnetar spin
period of Pspin∼7.2ms, and magnetic field of B∼1014G, and
fNi≲0.2 (consistent with SNe Ic). The prominent second peak cannot
be naturally accommodated with radioactive heating or magnetar
spin-down, but instead can be explained as circumstellar interaction
with ∼0.7M☉ of hydrogen-free material located ∼400au from the
progenitor. Accounting for the ejecta mass, circumstellar shell mass,
and remnant neutron star mass, we infer a CO core mass prior to
explosion of ∼6.5M☉. The host galaxy has a metallicity of
∼0.26Z☉, low for SNe Ic but consistent with SLSNe. Overall, we
find that SN 2019stc is a transition object between normal SNe Ic and
SLSNe.
Description:
We obtained optical images of SN 2019stc in the griz filters with
three different telescopes: KeplerCam on the 1.2m telescope at Fred
Lawrence Whipple Observatory (FLWO), the Low Dispersion Survey
Spectrograph (LDSS3c) on the Magellan Clay 6.5m telescope at Las
Campanas Observatory, and Binospec on the MMT 6.5-m telescope.
We include additional photometry from the Zwicky Transient Facility
(ZTF) images. We downloaded the original ZTF images from the NASA/IPAC
Infrared Science Archive.
We also obtained seven epochs (spanning 2019-Nov-23 to 2020-Nov-19) of
low-resolution optical spectroscopy covering phases from 15 to 340
days. We used the LDSS3c Spectrograph and Inamori-Magellan Areal
Camera and Spectrograph (IMACS) on the Magellan 6.5m telescopes and
the Blue Channel and Binospec spectrographs on the MMT 6.5m telescope.
See Section 2.3.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
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06 54 23.10 +17 29 31.3 ZTF19acbonaa = SN 2019stc
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2.dat 55 153 Optical light curves of SN 2019stc in the griz bands
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See also:
J/ApJ/741/97 : Light curves of Ibc supernovae (Drout+, 2011)
J/AJ/147/99 : Spectroscopy of 73 stripped core-collapse SNe (Modjaz+, 2014)
J/A+A/618/A37 : Spectral log of (i)PTF stripped-envelope SN (Fremling+, 2018)
J/ApJ/881/87 : 9 epochs spectroscopy of type I SN 201iet (Gomez+, 2019)
J/ApJ/887/169 : UV-Opt light curves of the type Ic SN 2018gep (Ho+, 2019)
J/ApJ/901/61 : LCs of 4 superluminous SNe from the ZTF survey (Lunnan+, 2020)
J/ApJ/902/L8 : Optical & NIR spectra of ZTF19aawfbtg (SN2019hge) (Yan+, 2020)
Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 14 F14.8 d MJD [58745.49/59174.5] Modified Julian Date of
observation (JD-2400000.5)
16 A1 --- l_omag Upper limit flag on omag
17- 24 F8.5 mag omag [18.69/25.77] Observed AB magnitude in Filt
26- 34 F9.6 mag e_omag [0.02/0.6]?=-1 Uncertainty in omag
36 A1 --- Filt Filter (g, r, i or z)
38- 46 A9 --- Tel Telescope/Instrument used (1)
48- 52 A5 --- uLim Is the measurement an upper limit;
"False" or "True"; e_omag=-1 if "True"
54- 55 A2 --- Syst Photometric System (always "AB")
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Note (1): Telescope/Instrument used as follows:
ZTF = Zwicky Transient Facility, Palomar 48-inch Telescope
(66 occurrences);
KeplerCam = KeplerCam Imager, Fred Lawrence Whipple Observatory 48-inch
Telescope (63 occurrences);
Binospec = Binospec Spectrograph, MMT Telescope (15 occurrences);
LDSS3c = Low Dispersion Survey Spectrograph, Magellan Telescopes
(9 occurrences);
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Nov-2022