The host galaxy of FRB 20171020A revisited

Karen Lee-Waddell*, Clancy W. James, Stuart D. Ryder, Elizabeth K. Mahony, Arash Bahramian, Bärbel S. Koribalski, Pravir Kumar, Lachlan Marnoch, Freya O. North-Hickey, Elaine M. Sadler, Ryan Shannon, Nicolas Tejos, Jessica E. Thorne, Jing Wang, Randall Wayth

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
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The putative host galaxy of FRB 20171020A was first identified as ESO 601-G036 in 2018, but as no repeat bursts have been detected, direct confirmation of the host remains elusive. In light of recent developments in the field, we re-examine this host and determine a new association confidence level of 98%. At 37 Mpc, this makes ESO 601-G036 the third closest FRB host galaxy to be identified to date and the closest to host an apparently non-repeating FRB (with an estimated repetition rate limit of < 0.011 bursts per day above 1039 erg). Due to its close distance, we are able to perform detailed multi-wavelength analysis on the ESO 601-G036 system. Follow-up observations confirm ESO 601-G036 to be a typical star-forming galaxy with H I and stellar masses of log10(MH I/M) ∼ 9.2 and log10(M/M) = 8.64+0.03−0.15, and a star formation rate of SFR = 0.09 ± 0.01 M yr−1 . We detect, for the first time, a diffuse gaseous tail (log10(MHI/M⊙)∼8.3) extending to the south-west that suggests recent interactions, likely with the confirmed nearby companion ESO 601-G037. ESO 601-G037 is a stellar shred located to the south of ESO 601-G036 that has an arc-like morphology, is about an order of magnitude less massive, and has a lower gas metallicity that is indicative of a younger stellar population. The properties of the ESO 601-G036 system indicate an ongoing minor merger event, which is affecting the overall gaseous component of the system and the stars within ESO 601-G037. Such activity is consistent with current FRB progenitor models involving magnetars and the signs of recent interactions in other nearby FRB host galaxies.

Original languageEnglish
Article numbere029
Pages (from-to)1-14
Number of pages14
JournalPublications of the Astronomical Society of Australia
Publication statusPublished - 11 Jul 2023

Bibliographical note

Copyright © The Author(s), 2023. Published by Cambridge University Press on behalf of the Astronomical Society of Australia. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


  • fast radio bursts
  • galaxies: individual: ESO 601-G036
  • galaxies: interactions


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