We report a Giant Metrewave Radio Telescope
We report on the commensal ASKAP detection of a fast radio burst (FRB), FRB 20211127I, and the detection of neutral hydrogen (H
- NSF-PAR ID:
- 10415611
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 949
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- Article No. 25
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract 21 cm mapping study of the neutral atomic hydrogen (H i ) in the host galaxy of the fast radio burst (FRB) FRB 20180916B atz ≈ 0.03399. We find that the FRB host has an Hi mass ofM Hi = (2.74 ± 0.33) × 109M ⊙and a high Hi to 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 Hi in the recent past. The Hi distribution is disturbed, with extended Hi 21 cm emission detected in a northeastern tail, a counter-tail toward the south, an Hi hole between the galaxy center and the FRB location, and a high Hi column density measured close to the FRB position. The FRB host is part of a group with four companions detected in their Hi 21 cm emission, the nearest of which is only 22 kpc from the FRB location. The gas richness and disturbed Hi distribution indicate that the FRB host has recently undergone a minor merger, which increased its Hi mass, disturbed the Hi in the galaxy disk, and compressed the Hi near 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. -
Abstract We present the discovery of neutral gas detected in both damped Ly
α absorption (DLA) and Hi 21 cm emission outside of the stellar body of a galaxy, the first such detection in the literature. A joint analysis between the Cosmic Ultraviolet Baryon Survey and the MeerKAT Absorption Line Survey reveals an Hi bridge connecting two interacting dwarf galaxies (log (M star/M ⊙) = 8.5 ± 0.2) that host az = 0.026 DLA with log[N (Hi )/cm−2] = 20.60 ± 0.05 toward the QSO J2339−5523 (z QSO= 1.35). At impact parameters ofd = 6 and 33 kpc, the dwarf galaxies have no companions more luminous than ≈0.05L *within at least Δv = ±300 km s−1andd ≈ 350 kpc. The Hi 21 cm emission is spatially coincident with the DLA at the 2σ –3σ level per spectral channel over several adjacent beams. However, Hi 21 cm absorption is not detected against the radio-bright QSO; if the background UV and radio sources are spatially aligned, the gas is either warm or clumpy (with a spin temperature to covering factor ratioT s /f c > 1880 K). Observations with VLT-MUSE demonstrate that theα -element abundance of the ionized interstellar medium (ISM) is consistent with the DLA (≈10% solar), suggesting that the neutral gas envelope is perturbed ISM gas. This study showcases the impact of dwarf–dwarf interactions on the physical and chemical state of neutral gas outside of star-forming regions. In the SKA era, joint UV and Hi 21 cm analyses will be critical for connecting the cosmic neutral gas content to galaxy environments. -
Abstract We report the detection and interferometric localization of the repeating fast radio burst (FRB) source FRB 20220912A during commissioning observations with the Deep Synoptic Array (DSA-110). Two bursts were detected from FRB 20220912A, one each on 2022 October 18 and 2022 October 25. The best-fit position is (R.A. J2000, decl. J2000) = (23:09:04.9, +48:42:25.4), with a 90% confidence error ellipse with radii ±2″ and ±1″ in R.A. and decl., respectively. The two bursts are polarized, and we find a Faraday rotation measure that is consistent with the low value of +0.6 rad m−2reported by CHIME/FRB. The DSA-110 localization overlaps with the galaxy PSO J347.2702+48.7066 at a redshift
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