Searching For Fermi GRB Optical Counterparts With The Prototype Gravitational-Wave Optical Transient Observer (GOTO)

Abstract

The typical detection rate of $\sim 1$ gamma-ray burst (GRB) per day by the \emph{Fermi} Gamma-ray Burst Monitor (GBM) provides a valuable opportunity to further our understanding of GRB physics. However, the large uncertainty of the \emph{Fermi} localization typically prevents rapid identification of multi-wavelength counterparts. We report the follow-up of 93 \emph{Fermi} GRBs with the Gravitational-wave Optical Transient Observer (GOTO) prototype on La Palma. We selected 53 events (based on favourable observing conditions) for detailed analysis, and to demonstrate our strategy of searching for optical counterparts. We apply a filtering process consisting of both automated and manual steps to 60\,085 candidates initially, rejecting all but 29, arising from 15 events. With $\approx 3$ GRB afterglows expected to be detectable with GOTO from our sample, most of the candidates are unlikely to be related to the GRBs. Since we did not have multiple observations for those candidates, we cannot confidently confirm the association between the transients and the GRBs. Our results show that GOTO can effectively search for GRB optical counterparts thanks to its large field of view of $\approx 40$ square degrees and its depth of $\approx 20$ mag. We also detail several methods to improve our overall performance for future follow-up programs of \emph{Fermi} GRBs.

References in corpus (16)

• Multi-messenger Observations of a Binary Neutron Star Merger
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• The Supernova -- Gamma-Ray Burst Connection
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational Wave Event GW170817
• The First Swift BAT Gamma-Ray Burst Catalog
• The Second Data Release of the INT Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS DR2)
• Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor
• Revisiting the Long/Soft-Short/Hard Classification of Gamma-Ray Bursts in the Fermi Era
• Evolution of Cataclysmic Variables and Related Binaries Containing a White-Dwarf
• iPTF14yb: The First Discovery of a GRB Afterglow Independent of a High-Energy Trigger
• The Needle in the 100 deg2 Haystack: Uncovering Afterglows of Fermi GRBs with the Palomar Transient Factory
• Transient-optimised real-bogus classification with Bayesian Convolutional Neural Networks -- sifting the GOTO candidate stream
• 2900 square degree search for the optical counterpart of short gamma-ray burst GRB 180523B with the Zwicky Transient Facility
• The Gravitational-wave Optical Transient Observer (GOTO)
• Orphan GRB afterglow searches with the Pan-STARRS1 COSMOS survey

Cited by in corpus (4)

• In search of short gamma-ray burst optical counterpart with the Zwicky Transient Facility
• Self-Supervised Clustering on Image-Subtracted Data with Deep-Embedded Self-Organizing Map
• Discovery and Analysis of Afterglows from Poorly Localised GRBs with the Gravitational-wave Optical Transient Observer (GOTO) All-sky Survey
• GOTO identification and broadband modelling of the counterpart to the SVOM GRB 250818B