Browsing by Author "Kulkarni, Shrinivas R."

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    A Search for Relativistic Ejecta in a Sample of ZTF Broad-lined Type Ic Supernovae
    (2023) Corsi, Alessandra (TTU); Ho, Anna Y.Q.; Cenko, S. Bradley; Kulkarni, Shrinivas R.; Anand, Shreya; Yang, Sheng; Sollerman, Jesper; Srinivasaragavan, Gokul P.; Omand, Conor M.B.; Balasubramanian, Arvind (TTU); Frail, Dale A.; Fremling, Christoffer; Perley, Daniel A.; Yao, Yuhan; Dahiwale, Aishwarya S.; De, Kishalay; Dugas, Alison; Hankins, Matthew; Jencson, Jacob; Kasliwal, Mansi M.; Tzanidakis, Anastasios; Bellm, Eric C.; Laher, Russ R.; Masci, Frank J.; Purdum, Josiah N.; Regnault, Nicolas
    The dividing line between gamma-ray bursts (GRBs) and ordinary stripped-envelope core-collapse supernovae (SNe) is yet to be fully understood. Observationally mapping the variety of ejecta outcomes (ultrarelativistic, mildly relativistic, or nonrelativistic) in SNe of Type Ic with broad lines (Ic-BL) can provide a key test to stellar explosion models. However, this requires large samples of the rare SN Ic-BL events with follow-up observations in the radio, where fast ejecta can be probed largely free of geometry and viewing angle effects. Here, we present the results of a radio (and X-ray) follow-up campaign of 16 SNe Ic-BL detected by the Zwicky Transient Facility (ZTF). Our radio campaign resulted in four counterpart detections and 12 deep upper limits. None of the events in our sample is as relativistic as SN 1998bw and we constrain the fraction of SN 1998bw-like explosions to <19% (3σ Gaussian equivalent), a factor of ≈2 smaller than previously established. We exclude relativistic ejecta with radio luminosity densities in between ≈5 × 1027 erg s−1 Hz−1 and ≈1029 erg s−1 Hz−1 at t ≳ 20 days since explosion for ≈60% of the events in our sample. This shows that SNe Ic-BL similar to the GRB-associated SNe 1998bw, 2003lw, and 2010bh, or to the relativistic SNe 2009bb and iPTF17cw, are rare. Our results also exclude an association of the SNe Ic-BL in our sample with largely off-axis GRBs with energies E ≳ 1050 erg. The parameter space of SN 2006aj-like events (faint and fast-peaking radio emission) is, on the other hand, left largely unconstrained, and systematically exploring it represents a promising line of future research.
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    Dramatic Rebrightening of the Type-changing Stripped-envelope Supernova SN 2023aew
    (2024) Sharma, Yashvi; Sollerman, Jesper; Kulkarni, Shrinivas R.; Moriya, Takashi J.; Schulze, Steve; Barmentloo, Stan; Fausnaugh, Michael (TTU); Gal-Yam, Avishay; Jerkstrand, Anders; Ahumada, Tomás; Bellm, Eric C.; Das, Kaustav K.; Drake, Andrew; Fremling, Christoffer; Hale, David; Hall, Saarah; Hinds, K. R.; du Laz, Theophile Jegou; Karambelkar, Viraj; Kasliwal, Mansi M.; Masci, Frank J.; Miller, Adam A.; Nir, Guy; Perley, Daniel A.; Purdum, Josiah N.; Qin, Yu Jing; Rehemtulla, Nabeel; Rich, R. Michael; Riddle, Reed L.; Rodriguez, Antonio C.; Rose, Sam; Somalwar, Jean; Wise, Jacob L.; Wold, Avery; Yan, Lin; Yao, Yuhan
    Multipeaked supernovae with precursors, dramatic light-curve rebrightenings, and spectral transformation are rare, but are being discovered in increasing numbers by modern night-sky transient surveys like the Zwicky Transient Facility. Here, we present the observations and analysis of SN 2023aew, which showed a dramatic increase in brightness following an initial luminous (−17.4 mag) and long (∼100 days) unusual first peak (possibly precursor). SN 2023aew was classified as a Type IIb supernova during the first peak but changed its type to resemble a stripped-envelope supernova (SESN) after the marked rebrightening. We present comparisons of SN 2023aew’s spectral evolution with SESN subtypes and argue that it is similar to SNe Ibc during its main peak. P-Cygni Balmer lines are present during the first peak, but vanish during the second peak’s photospheric phase, before Hα resurfaces again during the nebular phase. The nebular lines ([O i], [Ca ii], Mg i], Hα) exhibit a double-peaked structure that hints toward a clumpy or nonspherical ejecta. We analyze the second peak in the light curve of SN 2023aew and find it to be broader than that of normal SESNe as well as requiring a very high 56Ni mass to power the peak luminosity. We discuss the possible origins of SN 2023aew including an eruption scenario where a part of the envelope is ejected during the first peak and also powers the second peak of the light curve through interaction of the SN with the circumstellar medium.