TY - JOUR
T1 - Luminous Late-time Radio Emission from Supernovae Detected by the Karl G. Jansky Very Large Array Sky Survey (VLASS)
AU - Stroh, Michael C.
AU - Terreran, Giacomo
AU - Coppejans, Deanne L.
AU - Bright, Joe S.
AU - Margutti, Raffaella
AU - Bietenholz, Michael F.
AU - De Colle, Fabio
AU - Demarchi, Lindsay
AU - Duran, Rodolfo Barniol
AU - Milisavljevic, Danny
AU - Murase, Kohta
AU - Paterson, Kerry
AU - Williams, Wendy L.
N1 - Publisher Copyright:
© 2021. The Author(s). Published by the American Astronomical Society..
PY - 2021/12/20
Y1 - 2021/12/20
N2 - We present a population of 19 radio-luminous supernovae (SNe) with emission reaching L ν ∼ 1026-1029 erg s-1 Hz-1 in the first epoch of the Very Large Array Sky Survey (VLASS) at 2-4 GHz. Our sample includes one long gamma-ray burst, SN 2017iuk/GRB 171205A, and 18 core-collapse SNe detected at ≈1-60 yr after explosion. No thermonuclear explosion shows evidence for bright radio emission, and hydrogen-poor progenitors dominate the subsample of core-collapse events with spectroscopic classification at the time of explosion (79%). We interpret these findings in the context of the expected radio emission from the forward shock interaction with the circumstellar medium (CSM). We conclude that these observations require a departure from the single wind-like density profile (i.e., ρ CSM ∝ r -2) that is expected around massive stars and/or from a spherical Newtonian shock. Viable alternatives include the shock interaction with a detached, dense shell of CSM formed by a large effective progenitor mass-loss rate, (Equation presented) yr-1 (for an assumed wind velocity of 1000 km s-1); emission from an off-axis relativistic jet entering our line of sight; or the emergence of emission from a newly born pulsar-wind nebula. The relativistic SN 2012ap that is detected 5.7 and 8.5 yr after explosion with L ν ∼ 1028 erg s-1 Hz-1 might constitute the first detections of an off-axis jet+cocoon system in a massive star. However, none of the VLASS SNe with archival data points are consistent with our model off-axis jet light curves. Future multiwavelength observations will distinguish among these scenarios. Our VLASS source catalogs, which were used to perform the VLASS cross-matching, are publicly available at https://doi.org/10.5281/zenodo.4895112.
AB - We present a population of 19 radio-luminous supernovae (SNe) with emission reaching L ν ∼ 1026-1029 erg s-1 Hz-1 in the first epoch of the Very Large Array Sky Survey (VLASS) at 2-4 GHz. Our sample includes one long gamma-ray burst, SN 2017iuk/GRB 171205A, and 18 core-collapse SNe detected at ≈1-60 yr after explosion. No thermonuclear explosion shows evidence for bright radio emission, and hydrogen-poor progenitors dominate the subsample of core-collapse events with spectroscopic classification at the time of explosion (79%). We interpret these findings in the context of the expected radio emission from the forward shock interaction with the circumstellar medium (CSM). We conclude that these observations require a departure from the single wind-like density profile (i.e., ρ CSM ∝ r -2) that is expected around massive stars and/or from a spherical Newtonian shock. Viable alternatives include the shock interaction with a detached, dense shell of CSM formed by a large effective progenitor mass-loss rate, (Equation presented) yr-1 (for an assumed wind velocity of 1000 km s-1); emission from an off-axis relativistic jet entering our line of sight; or the emergence of emission from a newly born pulsar-wind nebula. The relativistic SN 2012ap that is detected 5.7 and 8.5 yr after explosion with L ν ∼ 1028 erg s-1 Hz-1 might constitute the first detections of an off-axis jet+cocoon system in a massive star. However, none of the VLASS SNe with archival data points are consistent with our model off-axis jet light curves. Future multiwavelength observations will distinguish among these scenarios. Our VLASS source catalogs, which were used to perform the VLASS cross-matching, are publicly available at https://doi.org/10.5281/zenodo.4895112.
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U2 - 10.3847/2041-8213/ac375e
DO - 10.3847/2041-8213/ac375e
M3 - Article
AN - SCOPUS:85122485771
SN - 2041-8205
VL - 923
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L24
ER -