The AARTFAAC All Sky Monitor: System Design and Implementation

TL;DR

The paper presents the design and implementation of the AARTFAAC all sky monitor, a real-time low frequency radio transient detector based on LOFAR, capable of generating rapid sky images and triggering follow-up observations.

Contribution

It introduces a novel heterogeneous, hierarchical system architecture for real-time processing of high data rate radio sky images with low latency.

Findings

Successfully manages 240 Gbps data rate

Produces real-time sky images with minimal latency

Enables rapid detection and follow-up of radio transients

Abstract

The Amsterdam-ASTRON Radio Transients Facility And Analysis Center (AARTFAAC) all sky monitor is a sensitive, real time transient detector based on the Low Frequency Array (LOFAR). It generates images of the low frequency radio sky with spatial resolution of 10s of arcmin, MHz bandwidths, and a time cadence of a few seconds, while simultaneously but independently observing with LOFAR. The image timeseries is then monitored for short and bright radio transients. On detection of a transient, a low latency trigger will be generated for LOFAR, which can interrupt its schedule to carry out follow-up observations of the trigger location at high sensitivity and resolutions. In this paper, we describe our heterogeneous, hierarchical design to manage the 240 Gbps raw data rate, and large scale computing to produce real-time images with minimum latency. We discuss the implementation of the instrumentation, its performance, and scalability.