Talk detail

Participant	Mooley, Kunal
Institution	Caltech - 1200 E California Blvd MC 249-17 - Pasadena - CA - USA

Session	GB7	Accepted	Yes	Order	4	Time	17:15	30'
Talk	Oral abstract	Title	The Long-lived Radio Afterglow of GW170817
Coauthors	Mooley, Kunal P.; Hallinan, Gregg W.; Deller, Adam T; Corsi, Alessandra; Gottlieb, Ore; Nakar, Ehud; Hotokezaka, Kenta; Frail, Dale A.; Bourke, Stephen; De, Kishalay; Dobie, Dougal; Chandra, Poonam; Horesh, Assaf; Kaplan, David L.; Kasliwal, Mansi M.; Kulkarni, Shrinivas R.; Lazzati, Davide; Lenc, Emil; Lynch, Christine; Murphy, Eric; Murphy, Tara; Deller, Adam; Myers, Steven T.; Nissanke, Samaya; Piran, Tsvi; Singer, Leo P.; Bannister, Keith W.; Bhalerao, Varun; Carbone, Dario; Groot, Paul; Fender, Rob P.; Woudt, Patrick
Abstract	Radio afterglows of neutron star mergers inform us about the geometry and energy of the different ejecta components, and the physics of the shock occurring between the ejecta and the circum-burst environment. This information is complementary to the ejecta mass and composition information provided by the early-time optical emission arising from the r-process nucleosynthesis of the neutron-rich dynamical ejecta (i.e. the kilonova/macronova signature). The radio afterglow of GW170817 was first detected 16 days after the merger. It evolved slowly with time (t^0.8) and peaked at about 150 days post-merger. The observational data rule out an on-axis jet, similar to those seen in regular short gamma-ray bursts, and give credence to a jet-cocoon system where the jet has transferred some fraction of its energy to the dynamical ejecta and has either been completely choked or has been successful in punching through by the dynamical ejecta. I will give an overview of the radio discovery of GW170817, the properties of its radio afterglow, and discuss how recent VLBI observations of GW170817 will distinguish between the choked-jet cocoon and successful-jet cocoon (structured jet) models, thus verifying the relationship between neutron star mergers and short gamma-ray bursts. GW170817 represents only an initial exploration of a rich scientific landscape populated by the stellar evolution, explosion and eventual merger of massive binary systems. The study of radio afterglows of neutron star mergers detected by LIGO/Virgo in their upcoming observing runs will be able to address many unsolved questions such as: How much energy do mergers release? What fraction of mergers produce relativistic jets? What effect does viewing angle have on the afterglow?
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