Browsing by Author "Balasubramanian, Arvind (TTU)"

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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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    SN2019wxt: An Ultrastripped Supernova Candidate Discovered in the Electromagnetic Follow-up of a Gravitational Wave Trigger
    (2023) Shivkumar, Hinna; Jaodand, Amruta D.; Balasubramanian, Arvind (TTU); Fremling, Christoffer; Corsi, Alessandra (TTU); Tzanidakis, Anastasios; Nissanke, Samaya; Kasliwal, Mansi; Brightman, Murray; Raaijmakers, Geert; Madsen, Kristin Kruse; Harrison, Fiona; Carbone, Dario; Nayana, A. J.; Désert, Jean Michel; Andreoni, Igor
    We present optical, radio, and X-ray observations of a rapidly evolving transient SN2019wxt (PS19hgw), discovered during the search for an electromagnetic counterpart to the gravitational-wave (GW) trigger S191213g. Although S191213g was not confirmed as a significant GW event in the off-line analysis of LIGO-Virgo data, SN2019wxt remained an interesting transient due to its peculiar nature. The optical/near-infrared (NIR) light curve of SN2019wxt displayed a double-peaked structure evolving rapidly in a manner analogous to currently known ultrastripped supernovae (USSNe) candidates. This double-peaked structure suggests the presence of an extended envelope around the progenitor, best modeled with two components: (i) early-time shock-cooling emission and (ii) late-time radioactive 56Ni decay. We constrain the ejecta mass of SN2019wxt at M ej ≈ 0.20M ⊙, which indicates a significantly stripped progenitor that was possibly in a binary system. We also followed up SN2019wxt with long-term Chandra and Jansky Very Large Array observations spanning ∼260 days. We detected no definitive counterparts at the location of SN2019wxt in these long-term X-ray and radio observational campaigns. We establish the X-ray upper limit at 9.93 × 10−17 erg cm−2 s−1 and detect an excess radio emission from the region of SN2019wxt. However, there is little evidence for SN1993J- or GW170817-like variability of the radio flux over the course of our observations. A substantial host-galaxy contribution to the measured radio flux is likely. The discovery and early-time peak capture of SN2019wxt in optical/NIR observations during EMGW follow-up observations highlight the need for dedicated early, multiband photometric observations to identify USSNe.