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Title: A Fast Radio Burst Progenitor Born in a Galaxy Merger
Abstract We report a Giant Metrewave Radio Telescope21 cm mapping study of the neutral atomic hydrogen (Hi) in the host galaxy of the fast radio burst (FRB) FRB 20180916B atz≈ 0.03399. We find that the FRB host has an Himass ofMHi= (2.74 ± 0.33) × 109M⊙and a high Hito stellar mass ratio, ≈1.3. The FRB host is thus a gas-rich but near-quiescent galaxy that is likely to have acquired a significant mass of Hiin the recent past. The Hidistribution is disturbed, with extended Hi21 cm emission detected in a northeastern tail, a counter-tail toward the south, an Hihole between the galaxy center and the FRB location, and a high Hicolumn density measured close to the FRB position. The FRB host is part of a group with four companions detected in their Hi21 cm emission, the nearest of which is only 22 kpc from the FRB location. The gas richness and disturbed Hidistribution indicate that the FRB host has recently undergone a minor merger, which increased its Himass, disturbed the Hiin the galaxy disk, and compressed the Hinear the FRB location to increase its surface density. We propose that this merger caused the burst of star formation in the outskirts of the galaxy that gave rise to the FRB progenitor. The evidence for a minor merger is consistent with scenarios in which the FRB progenitor is a massive star, formed due to the merger event.  more » « less
Award ID(s):
1911140 1910471
PAR ID:
10362280
Author(s) / Creator(s):
; ;
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal Letters
Volume:
925
Issue:
2
ISSN:
2041-8205
Format(s):
Medium: X Size: Article No. L20
Size(s):
Article No. L20
Sponsoring Org:
National Science Foundation
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