The VLA Low Band Ionospheric and Transient Experiment (VLITE): A Commensal Sky Survey

TL;DR

VLITE is a commensal system on the VLA that simultaneously conducts low-frequency sky surveys and primary high-frequency observations, significantly expanding the VLA's scientific capabilities without additional resource demands.

Contribution

This paper introduces VLITE, a novel commensal low-frequency observing system on the VLA that operates concurrently with primary observations, enabling new transient and sky survey science.

Findings

Recorded over 6300 hours of sky data in the first year.

Achieved significant sky coverage and depth at 352 MHz.

Enabled new astrophysics and transient search programs.

Abstract

The US Naval Research Laboratory (NRL) and the National Radio Astronomy Observatory (NRAO) have collaborated to develop, install, and commission a new commensal system on the Karl G. Jansky Very Large Array (VLA). The VLA Low Band Ionospheric and Transient Experiment (VLITE) makes use of dedicated samplers and fibers to tap the signal from 10 VLA low band receivers and correlate those through a real-time DiFX correlator. VLITE allows for the simultaneous use of the VLA to observe primary science using the higher frequencies receivers (1-50 GHz) through the NRAO WIDAR correlator and lower frequencies through the DiFX correlator. VLITE operates during nearly all observing programs and provides 64 MHz of bandwidth centered at 352 MHz. The operation of VLITE requires no additional resources from the VLA system running the primary science and produces an ad-hoc sky survey. The commensal system greatly expands the capabilities of the VLA through value-added PI science, stand-alone astrophysics, the opening of a new window on transient searches, and serendipity. In the first year of operation we have recorded more than 6300 hours spread across the sky. We present an overview of the VLITE program, discuss the sky coverage and depth obtained during the first year of operation, and briefly outline the astrophysics and transients programs.