2019A&A...627A.106M


Query : 2019A&A...627A.106M

2019A&A...627A.106M - Astronomy and Astrophysics, volume 627A, 106-106 (2019/7-1)

Nature of the unusual transient AT 2018cow from HI observations of its host galaxy.

MICHALOWSKI M.J., KAMPHUIS P., HJORTH J., KANN D.A., DE UGARTE POSTIGO A., GALBANY L., FYNBO J.P.U., GHOSH A., HUNT L.K., KUNCARAYAKTI H., LE FLOC'H E., LESNIEWSKA A., MISRA K., NICUESA GUELBENZU A., PALAZZI E., RASMUSSEN J., RESMI L., ROSSI A., SAVAGLIO S., SCHADY P., SCHULZE S., THONE C.C., WATSON D., JOZSA G.I.G., SERRA P. and SMIRNOV O.M.

Abstract (from CDS):

Context. Unusual stellar explosions represent an opportunity to learn about both stellar and galaxy evolution. Mapping the atomic gas in host galaxies of such transients can lead to an understanding of the conditions that trigger them. Aims. We provide resolved atomic gas observations of the host galaxy, CGCG137-068, of the unusual and poorly understood transient AT 2018cow, which we obtained in searching for clues to understand its nature. We test whether it is consistent with a recent inflow of atomic gas from the intergalactic medium, as suggested for host galaxies of gamma-ray bursts (GRBs) and some supernovae (SNe). Methods. We observed the HI hyperfine structure line of the AT 2018cow host with the Giant Metrewave Radio Telescope. Results. There is no unusual atomic gas concentration near the position of AT 2018cow. The gas distribution is much more regular than the distributions of GRB/SN hosts. The AT 2018cow host has an atomic gas mass lower by 0.24 dex than predicted from its star formation rate (SFR) and is at the lower edge of the galaxy main sequence.In the continuum we detected the emission of AT 2018cow and of a star-forming region in the north-eastern part of the bar (away from AT 2018cow). This region hosts a third of the galaxy's SFR. Conclusions. The absence of atomic gas concentration close to AT 2018cow, along with a normal SFR and regular HI velocity field, sets CGCG137-068 apart from GRB/SN hosts studied in HI. The environment of AT 2018cow therefore suggests that its progenitor may not have been a massive star. Our findings are consistent with an origin of the transient that does not require a connection between its progenitor and gas concentration or inflow: an exploding low-mass star, a tidal disruption event, a merger of white dwarfs, or a merger between a neutron star and a giant star. We interpret the recently reported atomic gas ring in CGCG 137-068 as a result of internal processes connected with gravitational resonances caused by the bar.

Abstract Copyright: © ESO 2019

Journal keyword(s): dust - extinction - galaxies: individual: CGCG137-068 - galaxies: ISM - galaxies: star formation - radio lines: galaxies - supernovae: individual: AT 2018cow

VizieR on-line data: <Available at CDS (J/A+A/627/A106): list.dat fits/*>

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 SN 2010bh SN* 07 10 30.63 -56 15 19.7           SNIc 290 1
2 SN 2003lw SN* 08 02 30.1 -39 51 03       20.23   SNIc: 550 0
3 SN 2009bb SN* 10 31 33.92 -39 57 28.2           SNIc 169 1
4 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4369 2
5 GRB 111005A gB 14 53 15.60 -19 43 19.1           ~ 65 0
6 ICRF J160913.3+264129 Sy2 16 09 13.3196 +26 41 29.042   19       ~ 238 1
7 SN 2018cow SN* 16 16 00.254 +22 16 05.10           SNIb 238 0
8 2MASX J16160054+2216080 Q? 16 16 00.5814649776 +22 16 08.286167568   15.7       ~ 47 0
9 NVSS J161808+221332 rG 16 18 07.928 +22 13 32.97   14.9       ~ 34 0
10 SN 1998bw SN* 19 35 03.17 -52 50 46.1   14.09       SNIc 1830 2
11 GRB 060505 gB 22 07 03.440 -27 48 51.89           ~ 261 1

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