The University of Southampton
University of Southampton Institutional Repository

Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs: III. Stellar masses, star formation rates, and metallicities at z > 1

Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs: III. Stellar masses, star formation rates, and metallicities at z > 1
Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs: III. Stellar masses, star formation rates, and metallicities at z > 1

Aims. Long gamma-ray bursts (LGRB) have been proposed as promising tracers of star formation owing to their association with the core-collapse of massive stars. Nonetheless, previous studies we carried out at z < 1 support the hypothesis that the conditions necessary for the progenitor star to produce an LGRB (e.g. low metallicity), were challenging the use of LGRBs as star-formation tracers, at least at low redshift. The goal of this work is to characterise the population of host galaxies of LGRBs at 1 < z < 2, investigate the conditions in which LGRBs form at these redshifts and assess their use as tracers of star formation. Methods. We performed a spectro-photometric analysis to determine the stellar mass, star formation rate, specific star formation rate and metallicity of the complete, unbiased host galaxy sample of the Swift/BAT6 LGRB sample at 1 < z < 2. We compared the distribution of these properties to the ones of typical star-forming galaxies from the MOSDEF and COSMOS2015 Ultra Deep surveys, within the same redshift range. Results. We find that, similarly to z < 1, LGRBs do not directly trace star formation at 1 < z < 2, and they tend to avoid high-mass, high-metallicity host galaxies. We also find evidence for an enhanced fraction of starbursts among the LGRB host sample with respect to the star-forming population of galaxies. Nonetheless we demonstrate that the driving factor ruling the LGRB efficiency is metallicity. The LGRB host distributions can be reconciled with the ones expected from galaxy surveys by imposing a metallicity upper limit of logOH ∼ 8.55. We can determine upper limits on the fraction of super-solar metallicity LGRB host galaxies of ∼20%, 10% at z < 1, 1 < z < 2, respectively. Conclusions. Metallicity rules the LGRB production efficiency, which is stifled at Z≳ 0.7 Z · . Under this hypothesis we can expect LGRBs to trace star formation at z > 3, once the bulk of the star forming galaxy population are characterised by metallicities below this limit. The role played by metallicity can be explained by the conditions necessary for the progenitor star to produce an LGRB. The moderately high metallicity threshold found is in agreement with the conditions necessary to rapidly produce a fast-rotating Wolf-Rayet stars in close binary systems, and could be accommodated by single star models under chemically homogeneous mixing with very rapid rotation and weak magnetic coupling.

Galaxies: abundances, Galaxies: star formation, Gamma-ray burst: general
0004-6361
Palmerio, J. T.
fba159b2-0901-4c6d-b0e2-050486c82103
Vergani, S. D.
3d593c19-410e-4ace-8dff-1862199ee0e5
Salvaterra, R.
8bfc09c8-fef4-407e-bfea-5a86e8a90043
Sanders, R. L.
60b4630d-9c19-4b1e-aae0-216b53d84018
Japelj, J.
69d23109-3694-40ff-96a8-1dac41cc214c
Vidal-García, A.
c296bcf2-e24a-4561-8ceb-64a2d2510e68
D'Avanzo, P.
41a3a281-101d-433e-a025-60df56d80668
Corre, D.
53733fd2-bf27-443b-b5c3-7c2aacd7abef
Perley, D. A.
1461c78a-63ce-4d55-90bd-fb15c122368e
Shapley, A. E.
435ab83d-a6a8-403b-8dea-8b54d2417b62
Boissier, S.
c0424407-225c-464a-b515-fefecbc48855
Greiner, J.
d9bc880b-1515-4291-b794-dd81b4e28c86
Le Floc'h, E.
29c2fc47-1082-4ece-a87d-8b74618be3f5
Wiseman, P.
865f95f8-2200-46a8-bd5e-3ee30bb44072
Palmerio, J. T.
fba159b2-0901-4c6d-b0e2-050486c82103
Vergani, S. D.
3d593c19-410e-4ace-8dff-1862199ee0e5
Salvaterra, R.
8bfc09c8-fef4-407e-bfea-5a86e8a90043
Sanders, R. L.
60b4630d-9c19-4b1e-aae0-216b53d84018
Japelj, J.
69d23109-3694-40ff-96a8-1dac41cc214c
Vidal-García, A.
c296bcf2-e24a-4561-8ceb-64a2d2510e68
D'Avanzo, P.
41a3a281-101d-433e-a025-60df56d80668
Corre, D.
53733fd2-bf27-443b-b5c3-7c2aacd7abef
Perley, D. A.
1461c78a-63ce-4d55-90bd-fb15c122368e
Shapley, A. E.
435ab83d-a6a8-403b-8dea-8b54d2417b62
Boissier, S.
c0424407-225c-464a-b515-fefecbc48855
Greiner, J.
d9bc880b-1515-4291-b794-dd81b4e28c86
Le Floc'h, E.
29c2fc47-1082-4ece-a87d-8b74618be3f5
Wiseman, P.
865f95f8-2200-46a8-bd5e-3ee30bb44072

Palmerio, J. T., Vergani, S. D., Salvaterra, R., Sanders, R. L., Japelj, J., Vidal-García, A., D'Avanzo, P., Corre, D., Perley, D. A., Shapley, A. E., Boissier, S., Greiner, J., Le Floc'h, E. and Wiseman, P. (2019) Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs: III. Stellar masses, star formation rates, and metallicities at z > 1. Astronomy and Astrophysics, 623, [A26]. (doi:10.1051/0004-6361/201834179).

Record type: Article

Abstract

Aims. Long gamma-ray bursts (LGRB) have been proposed as promising tracers of star formation owing to their association with the core-collapse of massive stars. Nonetheless, previous studies we carried out at z < 1 support the hypothesis that the conditions necessary for the progenitor star to produce an LGRB (e.g. low metallicity), were challenging the use of LGRBs as star-formation tracers, at least at low redshift. The goal of this work is to characterise the population of host galaxies of LGRBs at 1 < z < 2, investigate the conditions in which LGRBs form at these redshifts and assess their use as tracers of star formation. Methods. We performed a spectro-photometric analysis to determine the stellar mass, star formation rate, specific star formation rate and metallicity of the complete, unbiased host galaxy sample of the Swift/BAT6 LGRB sample at 1 < z < 2. We compared the distribution of these properties to the ones of typical star-forming galaxies from the MOSDEF and COSMOS2015 Ultra Deep surveys, within the same redshift range. Results. We find that, similarly to z < 1, LGRBs do not directly trace star formation at 1 < z < 2, and they tend to avoid high-mass, high-metallicity host galaxies. We also find evidence for an enhanced fraction of starbursts among the LGRB host sample with respect to the star-forming population of galaxies. Nonetheless we demonstrate that the driving factor ruling the LGRB efficiency is metallicity. The LGRB host distributions can be reconciled with the ones expected from galaxy surveys by imposing a metallicity upper limit of logOH ∼ 8.55. We can determine upper limits on the fraction of super-solar metallicity LGRB host galaxies of ∼20%, 10% at z < 1, 1 < z < 2, respectively. Conclusions. Metallicity rules the LGRB production efficiency, which is stifled at Z≳ 0.7 Z · . Under this hypothesis we can expect LGRBs to trace star formation at z > 3, once the bulk of the star forming galaxy population are characterised by metallicities below this limit. The role played by metallicity can be explained by the conditions necessary for the progenitor star to produce an LGRB. The moderately high metallicity threshold found is in agreement with the conditions necessary to rapidly produce a fast-rotating Wolf-Rayet stars in close binary systems, and could be accommodated by single star models under chemically homogeneous mixing with very rapid rotation and weak magnetic coupling.

Text
aa34179-18 - Version of Record
Available under License Creative Commons Attribution.
Download (4MB)

More information

Accepted/In Press date: 8 January 2019
e-pub ahead of print date: 26 February 2019
Keywords: Galaxies: abundances, Galaxies: star formation, Gamma-ray burst: general

Identifiers

Local EPrints ID: 429054
URI: http://eprints.soton.ac.uk/id/eprint/429054
ISSN: 0004-6361
PURE UUID: e687b30f-2d66-4606-a41a-b338f76e5090
ORCID for P. Wiseman: ORCID iD orcid.org/0000-0002-3073-1512

Catalogue record

Date deposited: 20 Mar 2019 17:30
Last modified: 16 Mar 2024 04:32

Export record

Altmetrics

Contributors

Author: J. T. Palmerio
Author: S. D. Vergani
Author: R. Salvaterra
Author: R. L. Sanders
Author: J. Japelj
Author: A. Vidal-García
Author: P. D'Avanzo
Author: D. Corre
Author: D. A. Perley
Author: A. E. Shapley
Author: S. Boissier
Author: J. Greiner
Author: E. Le Floc'h
Author: P. Wiseman ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×