GReX: An Instrument Overview and New Upper Limits on the Galactic FRB Population
Creators
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Shila, Kiran A.1
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Niedbalski, Sashabaw2
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Connor, Liam3
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Kulkarni, Shrinivas R.1
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Segev, Larom3
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Shukla, Priya1, 4
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Keane, Evan F.5
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McCauley, Joseph5
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Johnson, Owen A.5, 6
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Watters, Brendan5
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Farah, Wael7
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Pollak, Alexander W.7
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Belov, Konstantin1
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Tang, Honglue3
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Huai, Zhaoyu1
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Chatterjee, Shami2
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Cordes, James M.2
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1.
California Institute of Technology
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2.
Cornell University
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Harvard-Smithsonian Center for Astrophysics
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Raman Research Institute
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Trinity College Dublin
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University of California, Berkeley
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7.
Search for Extraterrestrial Intelligence
Abstract
We present the instrument design and initial results for the Galactic Radio Explorer, an all-sky monitor for exceptionally bright transients in the radio sky. This instrument builds on the success of STARE2 to search for fast radio bursts (FRBs) from the Milky Way and its satellites. This instrument has deployments across the globe, with wide sky coverage and searching down to 32 μs time resolution, enabling the discovery of new super giant pulses. Presented here are the details of the hardware and software design of the instrument, performance in sensitivity and other key metrics, and experience in building a global-scale, low-cost experiment. We follow this discussion with experimental results on validation of the sensitivity via hydrogen-line measurements. We then update the rate of Galactic FRBs based on non-detection in the time since FRB 200428. Our results suggest FRB-like events are even rarer than initially implied by the detection of a MJy burst from SGR J1935+2154 in 2020 April.
Copyright and License
© 2025. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
The authors would like to thank Courtney Keeler and David Hodge for all the assistance constructing, testing, and shipping the boxes. They would also like to acknowledge the staff at OVRO, HCRO, Rosse Observatory, and CSIRO for their assistance testing and working on deploying these instruments on site. The Rosse Observatory, in Birr, is operated by Trinity College Dublin. E.F.K. acknowledges that the GReX unit in Birr was made possible thanks to a grant from the Trinity College Dublin Association and Trust. O.A.J. acknowledges the support of Breakthrough Listen, which is managed by the Breakthrough Prize Foundation. Support for the construction of GReX was provided by Mt. Cuba Astronomical Foundation and a private donation from Terry Cisco.
Software References
GNU Parallel (Tange 2025), Astropy (Astropy Collaboration et al. 2013, 2018, 2022), HEALPix (Górski et al. 2005), PSRDADA (van Straten et al. 2021), HEIMDALL (Barsdell et al. 2012).
Files
10.1088_1538-3873_ade401.pdf
Additional details
Related works
- Is new version of
- Discussion Paper: arXiv:2504.18680 (arXiv)
Funding
- Trinity College Dublin
- Breakthrough Prize Foundation
- Mt. Cuba Astronomical Foundation
Dates
- Accepted
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2025-06-12
- Available
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2025-07-07Published
Caltech Custom Metadata
- Caltech groups
- Astronomy Department , Division of Physics, Mathematics and Astronomy (PMA)
- Publication Status
- Published