J/A+A/708/A305 SN 2020lao light curves (Stritzinger+, 2026)
The broad-lined type Ic supernova 2020lao reveals an energetic explosion with
no central-engine signatures.
Stritzinger M.D., Moriya T.J., Bose S., Mazzali P.A., Lundqvist P.,
Karamehmetoglu E., Arndt L.S., Ashall C., Galbany L., Hoogendam W.B.,
Baron E., DerKacy J.M., Elias-Rosa N., Hsiao E.Y., Hoeflich P., Pian E.,
Jensen E.A.M., Moran S., Pastorello A., Shahbandeh M., Valerin G.
<Astron. Astrophys. 708, A305 (2026)>
=2026A&A...708A.305S 2026A&A...708A.305S (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry ; Optical
Keywords: adiative transfer - gamma-ray burst: general - supernovae: general -
supernovae: individual: SN 2020lao
Abstract:
We present infant-phase observations of the broad-lined Type Ic
supernova (SN) 2020lao, including optical spectroscopy beginning
within about 48 hours of the inferred explosion epoch and extending to
nearly 100 days. The explosion time is constrained by power- law fits
to the rising TESS and ZTF light curves, with the first ZTF detection
occurring only ∼27 hours after explosion. The optical light curves
show a rapid rise of ~=8.8 days and a peak luminosity typical of SNe
Ic-BL (i.e., Mr~=-18.5mag). Unlike some engine- driven SNe Ic-BL
events, the early light curve of SN 2020lao shows no evidence of an
optical afterglow or excess emission, and the absence of any
detectable shock-cooling component in the TESS/ZTF data constrains
the progenitor to a compact Wolf-Rayet like star with R* ≲ few
R☉ , ruling out any extended envelope. The spectra resemble
those of the X-ray flash associated SN 2006aj but with systematically
higher expansion velocities. From Arnett-type fits to the bolometric
light curve and measured FeII λ5169 line velocities, we infer a
56Ni mass of 0.23±0.03 M☉, an ejecta mass (Mej) of
3.2±0.8M☉ , and a kinetic energy of
EK~(23.1±12.4)x10^516erg, corresponding to a specific kinetic
energy of EK/Mej~=(7.2±3.5)x1051erg/M☉. Spectral
synthesis modeling broadly reproduces the photospheric-phase spectra
of SN 2020lao and suggest EK/Mej~=4.9x1051erg/M☉. SN
2020lao and SN 2006aj synthesized comparable amounts of 56Ni, yet SN
2020lao exhibits EK/Mej values on the order of 5-10 times larger.
Published VLA and Swift/XRT non-detections reveal no afterglow
emission, imposing stringent limits on relativistic ejecta and dense
circumstellar material. Given that SN 2020lao reaches a specific
kinetic energy typical of engine-driven SNe Ic-BL, lack of an early
optical excess together with the non-detections in the radio and X-ray
bands suggest that if a relativistic jet was launched, the explosion
must have been viewed far off axis or the jet was choked before
breakout. Otherwise, SN 2020lao represents an extreme non-relativistic
SN Ic-BL. This underscores the importance of continued infant-phase,
multi-wavelength monitoring of these explosions.
Description:
We present infant-phase observations of the broad-lined Type Ic
supernova (SN) 2020lao, including optical spectroscopy beginning
within about 48 hours of the inferred explosion epoch and extending to
nearly 100 days.
Objects:
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RA (2000) DE Designation(s)
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17 06 54.60 +30 16 17.4 SN 2020lao = ZTF20abbplei
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 43 241 Photometry of SN 2020lao in the AB system
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 8 F8.2 d MJD Modifier Julian date
11- 16 F6.3 mag mag Magnitude in Filter
22- 26 F5.3 mag e_mag Magnitude error in filter (1)
33 A1 --- Filter [BVgri] Filter
39- 43 A5 --- Inst Facility (2)
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Note (1): Quoted uncertainties correspond to photometry error and nightly
zero-point error added in quadrature.
Note (2): Facility acronyms as follows:
LT = Liverpool Telescope
LCOGT = Las Cumbres Observatory
NOT = Nordic Optical Telescope
ZTF = Zwicky Transient Factory
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Acknowledgements:
Maximilian Stritzinger, max(at)phys.au.dk
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Patricia Vannier [CDS] 12-Mar-2026