Commissioning of FLAG: A phased array feed for the GBT

TL;DR

The paper reports on the commissioning and capabilities of FLAG, a highly sensitive phased array feed for the Green Bank Telescope, demonstrating significant improvements in pulsar survey speed and successful detection of various pulsars.

Contribution

It introduces the FLAG PAF system with 19 dual-polarization elements, achieving a system temperature of around 17 K and demonstrating its science capabilities during early observations.

Findings

Achieved a system temperature of ~17 K with FLAG.

Demonstrated threefold increase in pulsar survey speed.

Detected giant pulses from PSR B1937+21.

Abstract

Phased Array Feed (PAF) technology is the next major advancement in radio astronomy in terms of combining high sensitivity and large field of view. The Focal L-band Array for the Green Bank Telescope (FLAG) is one of the most sensitive PAFs developed so far. It consists of 19 dual-polarization elements mounted on a prime focus dewar resulting in seven beams on the sky. Its unprecedented system temperature of$\sim$17 K will lead to a 3 fold increase in pulsar survey speeds as compared to contemporary single pixel feeds. Early science observations were conducted in a recently concluded commissioning phase of the FLAG where we clearly demonstrated its science capabilities. We observed a selection of normal and millisecond pulsars and detected giant pulses from PSR B1937+21.