The Needle in the 100 deg2 Haystack: Uncovering Afterglows of Fermi GRBs with the Palomar Transient Factory

Abstract

The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi GRB Monitor instrument have posed a formidable obstacle to locating the bursts' host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target-of-opportunity mode for the intermediate Palomar Transient Factory in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: 8 afterglow discoveries out of 35 searches. Two of the bursts with detected afterglows (GRBs 130702A and 140606B) were at low redshift (z=0.145 and 0.384 respectively) and had spectroscopically confirmed broad-line Type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star, rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility, we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.

22 pages, 13 figures, 6 tables, 1 online figure set, 3 machine readable tables

References in corpus (23)

• An online repository of Swift/XRT light curves of GRBs
• An optical supernova associated with the X-ray flash XRF 060218
• GROND - a 7-channel imager
• A Wolf-Rayet-like progenitor of supernova SN 2013cu from spectral observations of a wind
• A Complete Catalog of Swift GRB Spectra and Durations: Demise of a Physical Origin for Pre-Swift High-Energy Correlations
• The Automated Palomar 60-Inch Telescope
• Early-Time Photometry and Spectroscopy of the Fast Evolving SN 2006AJ Associated with GRB 060218
• The First Two Years of Electromagnetic Follow-Up with Advanced LIGO and Virgo
• Neutron-powered precursors of kilonovae
• Supernova 2006aj and the associated X-Ray Flash 060218
• A Comparison of the Afterglows of Short- and Long-Duration Gamma-Ray Bursts
• Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor
• Accurate early positions for Swift GRBS: enhancing X-ray positions with UVOT astrometry
• Generalized Tests for Selection Effects in GRB High-Energy Correlations
• Luminosity function and jet structure of Gamma Ray Bursts
• Spectral analysis of Swift long GRBs with known redshift
• Probing the Bright Radio Flare and Afterglow of GRB 130427A with the Arcminute Microkelvin Imager
• A Trio of GRB-SNe: GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu
• The Zwicky Transient Facility
• Time-resolved spectral correlations of long-duration Gamma-Ray Bursts
• Synchrotron Self-inverse Compton Radiation From Reverse-shock on GRB120326A
• Time series data mining for the Gaia variability analysis
• Extremely Soft X-ray Flash as the indicator of off-axis orphan GRB afterglow

Cited by in corpus (21)

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• The Konus-Wind catalog of gamma-ray bursts with known redshifts. I. Bursts detected in the triggered mode
• Kilonova Luminosity Function Constraints based on Zwicky Transient Facility Searches for 13 Neutron Star Mergers
• The IPAC Image Subtraction and Discovery Pipeline for the intermediate Palomar Transient Factory
• Fast-transient Searches in Real Time with ZTFReST: Identification of Three Optically-discovered Gamma-ray Burst Afterglows and New Constraints on the Kilonova Rate
• Examining Two-Dimensional Luminosity-time Correlations for Gamma Ray Burst Radio Afterglows with VLA and ALMA
• Cosmological Fast Optical Transients with the Zwicky Transient Facility: A Search for Dirty Fireballs
• 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
• iPTF17cw: An engine-driven supernova candidate discovered independent of a gamma-ray trigger
• Improved Fermi-GBM GRB localizations using BALROG
• Accounting for Selection Bias and Redshift Evolution in GRB Radio Afterglow Data
• The Palomar Transient Factory Sky2Night programme
• Liverpool Telescope follow-up of candidate electromagnetic counterparts during the first run of Advanced LIGO
• Interpretation of Radio Afterglows in the framework of the Standard Fireball and Energy Injection models
• Searching For Fermi GRB Optical Counterparts With The Prototype Gravitational-Wave Optical Transient Observer (GOTO)
• In search of short gamma-ray burst optical counterpart with the Zwicky Transient Facility
• Geographic and seasonal influences on optical followup of gravitational wave events
• Machine-directed gravitational-wave counterpart discovery
• Son of X--Shooter: a multi--band instrument for a multi--band universe
• GOTO identification and broadband modelling of the counterpart to the SVOM GRB 250818B