Evaluation of Automated Fermi GBM Localizations of Gamma-ray Bursts

Abstract

The capability of the Fermi Gamma-ray Burst Monitor (GBM) to localize gamma-ray bursts (GRBs) is evaluated for two different automated algorithms: the GBM Team's RoboBA algorithm and the independently developed BALROG algorithm. Through a systematic study utilizing over 500 GRBs with known locations from instruments like Swift and the Fermi LAT, we directly compare the effectiveness of, and accurately estimate the systematic uncertainty for, both algorithms. We show simple adjustments to the GBM Team's RoboBA, in operation since early 2016, yields significant improvement in the systematic uncertainty, removing the long tail identified in the systematic, and improves the overall accuracy. The systematic uncertainty for the updated RoboBA localizations is $1.8^{\circ }$ for 52% of GRBs and $4.1^{\circ }$ for the remaining 48%. Both from public reporting by BALROG and our systematic study, we find the systematic uncertainty of $1-2^{\circ }$ quoted in GCN circulars for bright GRBs localized by BALROG is an underestimate of the true magnitude of the systematic, which we find to be $2.7^{\circ }$ for 74% of GRBs and $33^{\circ }$ for the remaining 26%. We show that, once the systematic uncertainty is considered, the RoboBA 90% localization confidence regions can be more than an order of magnitude smaller in area than those produced by BALROG.

arXiv commentAccepted for publication in ApJ. Added Appendix showing localization comparisons for each GRB in the near-realtime public reporting sample

References in corpus (17)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• The Fermi Gamma-Ray Burst Monitor
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor
• Evidence for Late-stage Eruptive Mass-loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient
• Search for Gravitational Waves Associated with Gamma-Ray Bursts During the First Advanced LIGO Observing Run and Implications for the Origin of GRB 150906B
• Discovery and redshift of an optical afterglow in 71 square degrees: iPTF13bxl and GRB 130702A
• The Interplanetary Network Supplement to the Fermi GBM Catalog of Cosmic Gamma-Ray Bursts
• The Needle in the 100 deg2 Haystack: Uncovering Afterglows of Fermi GRBs with the Palomar Transient Factory
• Search for gravitational-wave signals associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo
• 2900 square degree search for the optical counterpart of short gamma-ray burst GRB 180523B with the Zwicky Transient Facility
• A Search for High-Energy Counterparts to Fast Radio Bursts
• The optical identifcation of events with poorly defined locations: The case of the Fermi GBM GRB140801A
• The Error Distribution of BATSE GRB Locations
• iPTF17cw: An engine-driven supernova candidate discovered independent of a gamma-ray trigger
• Improved Fermi-GBM GRB localizations using BALROG

Cited by in corpus (25)

• Discovery and confirmation of the shortest gamma ray burst from a collapsar
• A bright gamma-ray flare interpreted as a giant magnetar flare in NGC 253
• Fast-transient Searches in Real Time with ZTFReST: Identification of Three Optically-discovered Gamma-ray Burst Afterglows and New Constraints on the Kilonova Rate
• Rapid Spectral Variability of a Giant Flare from a Magnetar in NGC 253
• Identification of a Local Sample of Gamma-Ray Bursts Consistent with a Magnetar Giant Flare Origin
• Searches for Neutrinos from Gamma-Ray Bursts using the IceCube Neutrino Observatory
• Kilonova Detectability with Wide-Field Instruments
• Orbital Foregrounds for Ultra-Short Duration Transients
• Search for 10--1000 GeV neutrinos from Gamma Ray Bursts with IceCube
• GECAM Localization of High Energy Transients and the Systematic Error
• The Large Array Survey Telescope -- Science Goals
• A search for lensed gamma-ray bursts in 11 years of observations by Fermi GBM
• Multi-messenger Gravitational Lensing
• Localisation of gamma-ray bursts from the combined SpIRIT+HERMES-TP/SP nano-satellite constellation
• HEALPix Alchemy: Fast All-Sky Geometry and Image Arithmetic in a Relational Database for Multimessenger Astronomy Brokers
• Gravitational wave triggered searches for high-energy neutrinos from binary neutron star mergers: prospects for next generation detectors
• In search of short gamma-ray burst optical counterpart with the Zwicky Transient Facility
• Fermi Gamma-ray Space Telescope
• The Second Catalog of Interplanetary Network Localizations of Konus Short Duration Gamma-Ray Bursts
• Real-time Likelihood Methods for Improved Gamma-ray Transient Detection and Localization
• Cross-Observatory Coordination with tilepy: A Novel Tool for Observations of Multi-Messenger Transient Events
• Deep Multimessenger Search for Compact Binary Mergers in LIGO, Virgo, and Fermi/GBM Data from 2016-2017
• Expanding the Population of Short Gamma-Ray Transients with a Coherent Fermi/GBM Search. A 13-year catalog of short GRBs
• TransientVerse: A Comprehensive Real-Time Alert and Multi-Wavelength Analysis System for Transient Astronomical Events
• GOTO identification and broadband modelling of the counterpart to the SVOM GRB 250818B