A Simultaneous Search for Prompt Radio Emission Associated with the Short GRB 170112A Using the All-sky Imaging Capability of the OVRO-LWA

We have conducted the most sensitive low-frequency (below 100 MHz) search to date for prompt, low-frequency radio emission associated with short-duration gamma-ray bursts (GRBs), using the Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA). The OVRO-LWA's nearly full-hemisphere field of view (~20,000 square degrees) allows us to search for low-frequency (sub-100 MHz) counterparts for a large sample of the subset of GRB events for which prompt radio emission has been predicted. Following the detection of short GRB 170112A by Swift, we used all-sky OVRO-LWA images spanning one hour prior to and two hours following the GRB event to search for a transient source coincident with the position of GRB 170112A. We detect no transient source to within a 3σ flux density limit of 4.5 Jy at 13 s timescales for frequencies spanning 27–84 MHz. We place constraints on a number of models predicting prompt, low-frequency radio emission accompanying short GRBs and their potential binary neutron star merger progenitors, and place an upper limit of L_(radio)/ L_γ ≾ 3.5 × 10^(−6) on the fraction of energy released in the prompt radio emission, under the assumptions of negligible scattering of the radio pulse and beaming of emission along the line of sight. These observations serve as a pilot effort for a program targeting a wider sample of both short and long GRBs with the OVRO-LWA, including bursts with confirmed redshift measurements that are critical to placing constraining limits on prompt radio emission models, as well as a program for the follow-up of gravitational wave compact binary coalescence events detected by advanced LIGO and Virgo.