Speaker
Description
The joint detection of a short GRB and gravitational waves had long been a goal by astronomers that was finally realized with GRB/GW 170817A. The GRB emission was much dimmer than expected though, with a peak luminosity more than two orders of magnitude lower than any other short GRB known. This implies that there is a population of low-luminosity short GRBs and greatly motivates more sensitive GRB searches.
In 2019 GUANO, a system for saving time-tagged event data on command was implemented, enabling more sensitive searches to be run on the ground around times of interest. The most sensitive of these searches being the Non-Imaging Transient Reconstruction And TEmporal Search (NITRATES). NITRATES is a likelihood based analysis that increases the detection rates of a GRB like 170817A by a factor of ~5 over the onboard analysis. The NITRATES targeted search has been run on externally triggered GRBs for ~4 years now, resulting in dozens of arcminute-scale localizations that were not found onboard, 8 of them being short GRBs. NITRATES has also been targeted around GW, high-energy neutrinos, and FRB alerts.
In this talk I will go over recent results including the offline O3 gravitational wave observing run and the ongoing O4 run. I will also describe the low-latency alerts we distribute, including localizations that can vary from arcminute scale localizations to full sky probability maps.
