Title: Radio Exploration of the Host Galaxies of Massive Star Explosions<\/p>\n\n\n\n
Bunyo Hatsukade (Institute of Astronomy, Univ. of Tokyo)<\/p>\n\n\n\n
Abstract:<\/p>\n\n\n\n
I present the results of radio observations of the host galaxies of long
-duration gamma-ray bursts (GRBs) and superluminous supernovae (SLSNe).\u00a0
GRBs are associated with the explosion of massive stars. Because GRBs\u00a0
are bright enough to be observable in the cosmological distances, they\u00a0
are expected to be a new tool to probe the cosmic star-formation history.\u00a0
However, it is still a subject of debate whether they occur in normal\u00a0
star-forming environments or not. Observations of molecular gas, the\u00a0
fuel of star formation, are essential to understand the properties of\u00a0
host galaxies. We conducted ALMA CO observations toward GRB hosts at 0.1\u00a0
< z < 2.5 and obtained the largest sample of GRB hosts with molecular\u00a0
gas information. We find no systematic offset for the GRB hosts from the\u00a0
scaling relation of normal star-forming galaxies in terms of gas\u00a0
consumption timescale or gas fraction, suggesting that GRBs occur in\u00a0
normal star-forming environments.\u00a0
We are also working on radio continuum observations of SLSN hosts to\u00a0
constrain the obscured star formation. SLSNe are extremely luminous\u00a0
explosions, with peak magnitudes 10–100 times brighter than typical\u00a0
Type Ia and core-collapse SNe. The physical nature of SLSNe is still a\u00a0
matter of debate, and it is important to study the properties of their\u00a0
host galaxies. Our initial study found that four (out of eight) hosts at\u00a0
0.01 < z < 0.3 have an excess in radio-derived SFRs compared to\u00a0
optically-derived SFRs, suggesting the existence of obscured star\u00a0
formation, which cannot be traced by optical studies. This suggests a\u00a0
higher fraction of starburst galaxies in SLSN hosts than estimated in\u00a0
previous studies. I also present ongoing projects and radio constraints\u00a0
on a pulsar-driven SLSN model.\u00a0
<\/p>\n\n\n\n
Host contact: Akihiro Suzuki<\/p>\n","protected":false},"excerpt":{"rendered":"