CHIME/FRB Outriggers: KKO Station System and Commissioning Results

TL;DR

The paper reports on the commissioning and performance of the KKO outrigger telescope, enhancing CHIME's ability to localize fast radio bursts with high precision using VLBI techniques.

Contribution

It introduces the KKO outrigger system, demonstrates its standalone capabilities, and confirms its effectiveness in localizing pulsars within 5 arcseconds, paving the way for precise FRB localization.

Findings

KKO successfully produced full-sky images and mapped the primary beam.

Localization of pulsars within 5 arcseconds was achieved.

The system is ready for future FRB localization with additional outriggers.

Abstract

Localizing fast radio bursts (FRBs) to their host galaxies is an essential step to better understanding their origins and using them as cosmic probes. The CHIME/FRB Outrigger program aims to add VLBI-localization capabilities to CHIME, such that FRBs may be localized to tens of milliarcsecond precision at the time of their discovery, more than sufficient for host galaxy identification. The first-built outrigger telescope is KKO, located 66 kilometers west of CHIME. Cross-correlating KKO with CHIME can achieve arcsecond-scale localization in right ascension while avoiding the worst effects of the ionosphere. This paper presents measurements of KKO's performance throughout its commissioning phase, as well as a summary of its design and function. We demonstrate KKO's capabilities as a standalone instrument by producing full-sky images, mapping the angular and frequency structure of the primary beam, and measuring feed positions. To demonstrate the localization capabilities of the CHIME -- KKO baseline, we collected five separate observations each for a set of twenty bright pulsars, and aimed to measure their positions to within 5~arcseconds. All of these pulses were successfully localized to within this specification. The next two outriggers are expected to be commissioned in 2024, and will enable subarcsecond localizations for approximately hundreds of FRBs each year.