Deep ATCA and VLA Radio Observations of Short-GRB Host Galaxies. Constraints on Star Formation Rates, Afterglow Flux, and Kilonova Radio Flares

Journal
Date Issued
2019
Author(s)
Klose, S.
•
Nicuesa Guelbenzu, A. M.
•
Michałowski, M. J.
•
•
Hartmann, D. H.
•
Greiner, J.
•
•
•
Bernuzzi, S.
DOI
Abstract
We report the results of an extensive radio-continuum observing campaign of host galaxies of short gamma-ray bursts (GRBs). The goal of this survey was to search for optically obscured star formation, possibly indicative of a population of young short-GRB progenitors. Our sample comprises the hosts and host-galaxy candidates of 16 short-GRBs from 2005 to 2015, corresponding to roughly one-third of the presently known ensemble of well-localized short bursts. Eight GRB fields were observed with ATCA (at 5.5 and 9.0 GHz), and eight fields with the VLA (mostly at 5.5 GHz). The observations typically achieved a 1σ rms of 5-8 μJy. In most cases, they were performed years after the corresponding burst. No new short-GRB host with optically obscured star formation was found. Only one host galaxy was detected: that of GRB 100206A at z = 0.407. However, its starburst nature was already known from optical/IR data. Its measured radio flux can be interpreted as being due to a star formation rate of about 60 M ☉ yr-1. This is in good agreement with earlier expectations based on the observed broad-band spectral energy distribution of this galaxy. The 15 nondetections constrain the SFRs of the suspected host galaxies and provide upper limits on late-time luminosities of the associated radio afterglows and predicted kilonova radio flares. The nondetection of radio emission from GRB explosion sites confirms the intrinsically low luminosity of short-GRB afterglows and places significant constraints on the parameter space of magnetar-powered radio flares. Luminous radio flares from fiducial massive magnetars have not been found.
Volume
887
Issue
2
Start page
206
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2019ApJ...887..206K
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Klose_2019_ApJ_887_206.pdf

Description
pdf editoriale
Size

1.18 MB

Format

Adobe PDF

Checksum (MD5)

14dc63043db2d10c80de18bc56367cf9