Late-Time Radio and Millimeter Observations of Superluminous Supernovae and Long Gamma Ray Bursts: Implications for Obscured Star Formation, Central Engines, and Fast Radio Bursts

TL;DR

This study conducted the largest and deepest late-time radio and millimeter survey of superluminous supernovae and long gamma-ray bursts, finding mostly non-detections but setting important constraints on their central engines, star formation, and fast radio bursts.

Contribution

It provides new observational constraints on the late-time radio emission of SLSNe and LGRBs, informing models of their central engines and environments.

Findings

No significant radio/mm emission detected from most sources.

Constraints placed on magnetar wind nebulae and relativistic jets.

No fast radio bursts detected from the observed sources.

Abstract

We present the largest and deepest late-time radio and millimeter survey to date of superluminous supernovae (SLSNe) and long duration gamma-ray bursts (LGRBs) to search for associated non-thermal synchrotron emission. Using the Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA), we observed 43 sources at 6 and 100 GHz on a timescale of $\sim 1 - 19$ yr post-explosion. We do not detect radio/mm emission from any of the sources, with the exception of a 6 GHz detection of PTF10hgi (Eftekhari et al. 2019), as well as the detection of 6 GHz emission near the location of the SLSN PTF12dam, which we associate with its host galaxy. We use our data to place constraints on central engine emission due to magnetar wind nebulae and off-axis relativistic jets. We also explore non-relativistic emission from the SN ejecta, and place constraints on obscured star formation in the host galaxies. In addition, we conduct a search for fast radio bursts (FRBs) from some of the sources using VLA Phased-Array observations; no FRBs are detected to a limit of $16$ mJy ($7\sigma$; 10 ms duration) in about 40 min on source per event. A comparison to theoretical models suggests that continued radio monitoring may lead to detections of persistent radio emission on timescales of $\gtrsim {\rm decade}$.