Astronomy Tea Talk

Monday, October 3, 2022
4:00pm to 5:00pm
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Online and In-Person Event
The Transient Universe: Compact Objects Near and Far
Brendan O'Connor, The George Washington University / University of Maryland College Park,

Neutron stars (NSs) are at the center of modern time domain astronomy (TDA). They are often invoked to explain the most luminous, and explosive transients, such as magnetar giant flares, fast radio bursts, kilonovae, and gamma-ray bursts (GRBs). I study NSs both in our Galaxy and at cosmological distances, as these separate populations probe the formation and evolution of a variety of high energy transients. I will present a first-look at the results of the Swift Deep Galactic Plane Survey (DGPS), a NuSTAR Legacy Project and Swift Key Project, comprising 40 sq. deg. of the Galactic Plane (GP) covering 10<|l|<30 deg and |b|<0.5 deg. The DGPS goal is to produce a rich sample of new sources and transients (e.g. NSs), while also covering a broad discovery space. I will then discuss my work on the host galaxies and environments of short GRBs. Short GRBs were unambiguously connected to binary NS mergers through the simultaneous detection of GW170817 and GRB 170817A. As such, short GRBs play a significant role in astrophysics with far-reaching implications, from the rate of detectable gravitational wave (GW) events to the production of heavy elements in the Universe. Their environments and distance scales yield important information as to their progenitors and their formation channels, complementing the constraints derived from GW astronomy. I carried out an extensive observational campaign to study the host galaxies of short GRBs. I will present the results of my observing campaign, including deep Gemini, Keck and HST imaging of 31 short GRBs. I uncovered evidence for a redshift evolution in their locations within their hosts, and for a significant population of high redshift events. 

For more information, please contact Junhan Kim by email at junhank@caltech.edu or visit https://www.youtube.com/channel/UC-zYBv_IqFp2f9huYQA1VSw.