GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow

M.~J. Michalowski, J.~M. Castro Cerón, J.~L. Wardlow, A. Karska, H. Messias, P. van der Werf, L.~K. Hunt, M. Baes, A.~J. Castro-Tirado, G. Gentile, J. Hjorth, E. Le Floc'h, R. Pé rez-Martinez, A. Nicuesa Guelbenzu, J. Rasmussen, J.~R. Rizzo, A. Rossi, M. Sá nchez-Portal, P. Schady, J. Sollerman & 1 others D. Xu

Research output: Contribution to journalArticle

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Abstract

Context. Accretion of gas from the intergalactic medium is required to fuel star formation in galaxies. We have recently suggested that this process can be studied using host galaxies of gamma-ray bursts (GRBs). Aims. Our aim is to test this possibility by studying in detail the properties of gas in the closest galaxy hosting a GRB (980425). Methods. We obtained the first ever far-infrared (FIR) line observations of a GRB host, namely Herschel/PACS resolved [C II] 158 μm and [O I] 63 μm spectroscopy, and an APEX/SHeFI CO(2–1) line detection and ALMA CO(1–0) observations of the GRB 980425 host. Results. The GRB 980425 host has elevated [C II]/FIR and [O I]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C II], [O I], Hα) than from continuum (UV, IR, radio) indicators. [C II] emission exhibits a normal morphology, peaking at the galaxy centre, whereas [O I] is concentrated close to the GRB position and the nearby Wolf-Rayet region. The high [O I] flux indicates that there is high radiation field and high gas density at these positions, as derived from modelling of photo-dissociation regions. The [C II]/CO luminosity ratio of the GRB 980425 host is close to the highest values found for local star-forming galaxies. Indeed, its CO-derived molecular gas mass is low given its SFR and metallicity, but the [C II]-derived molecular gas mass is close to the expected value. Conclusions. The [O I] and H I concentrations and the high radiation field and density close to the GRB position are consistent with the hypothesis of a very recent (at most a few tens of Myr ago) inflow of atomic gas triggering star formation. In this scenario dust has not had time to build up (explaining high line-to-continuum ratios). Such a recent enhancement of star formation activity would indeed manifest itself in high SFRline/SFRcontinuum ratios because the line indicators are sensitive only to recent (≲10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (~100 Myr). Within a sample of 32 other GRB hosts, 20 exhibit SFRline/SFRcontinuum> 1 with a mean ratio of 1.74 ± 0.32. This is consistent with a very recent enhancement of star formation that is common among GRB hosts, so galaxies that have recently experienced inflow of gas may preferentially host stars exploding as GRBs. Therefore GRBs may be used to select a unique sample of galaxies that is suitable for the investigation of recent gas accretion.
Original languageEnglish
Pages (from-to)A72
JournalAstronomy & Astrophysics
Volume595
DOIs
Publication statusPublished - 1 Nov 2016

Keywords

  • dust, extinction, galaxies: individual: ESO 184-G82, galaxies: ISM, galaxies: star formation, submillimeter: galaxies, gamma-ray burst: individual: 980425, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena

Cite this

Michalowski, M. J., Castro Cerón, J. M., Wardlow, J. L., Karska, A., Messias, H., van der Werf, P., ... Xu, D. (2016). GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow. Astronomy & Astrophysics, 595, A72. https://doi.org/10.1051/0004-6361/201629441

GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow. / Michalowski, M.~J.; Castro Cerón, J.~M.; Wardlow, J.~L.; Karska, A.; Messias, H.; van der Werf, P.; Hunt, L.~K.; Baes, M.; Castro-Tirado, A.~J.; Gentile, G.; Hjorth, J.; Le Floc'h, E.; Pé rez-Martinez, R.; Nicuesa Guelbenzu, A.; Rasmussen, J.; Rizzo, J.~R.; Rossi, A.; Sá nchez-Portal, M.; Schady, P.; Sollerman, J.; Xu, D.

In: Astronomy & Astrophysics, Vol. 595, 01.11.2016, p. A72.

Research output: Contribution to journalArticle

Michalowski, MJ, Castro Cerón, JM, Wardlow, JL, Karska, A, Messias, H, van der Werf, P, Hunt, LK, Baes, M, Castro-Tirado, AJ, Gentile, G, Hjorth, J, Le Floc'h, E, Pé rez-Martinez, R, Nicuesa Guelbenzu, A, Rasmussen, J, Rizzo, JR, Rossi, A, Sá nchez-Portal, M, Schady, P, Sollerman, J & Xu, D 2016, 'GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow', Astronomy & Astrophysics, vol. 595, pp. A72. https://doi.org/10.1051/0004-6361/201629441
Michalowski, M.~J. ; Castro Cerón, J.~M. ; Wardlow, J.~L. ; Karska, A. ; Messias, H. ; van der Werf, P. ; Hunt, L.~K. ; Baes, M. ; Castro-Tirado, A.~J. ; Gentile, G. ; Hjorth, J. ; Le Floc'h, E. ; Pé rez-Martinez, R. ; Nicuesa Guelbenzu, A. ; Rasmussen, J. ; Rizzo, J.~R. ; Rossi, A. ; Sá nchez-Portal, M. ; Schady, P. ; Sollerman, J. ; Xu, D. / GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow. In: Astronomy & Astrophysics. 2016 ; Vol. 595. pp. A72.
@article{c89c817f59ff4ebd9a50f3841f95df9a,
title = "GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow",
abstract = "Context. Accretion of gas from the intergalactic medium is required to fuel star formation in galaxies. We have recently suggested that this process can be studied using host galaxies of gamma-ray bursts (GRBs). Aims. Our aim is to test this possibility by studying in detail the properties of gas in the closest galaxy hosting a GRB (980425). Methods. We obtained the first ever far-infrared (FIR) line observations of a GRB host, namely Herschel/PACS resolved [C II] 158 μm and [O I] 63 μm spectroscopy, and an APEX/SHeFI CO(2–1) line detection and ALMA CO(1–0) observations of the GRB 980425 host. Results. The GRB 980425 host has elevated [C II]/FIR and [O I]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C II], [O I], Hα) than from continuum (UV, IR, radio) indicators. [C II] emission exhibits a normal morphology, peaking at the galaxy centre, whereas [O I] is concentrated close to the GRB position and the nearby Wolf-Rayet region. The high [O I] flux indicates that there is high radiation field and high gas density at these positions, as derived from modelling of photo-dissociation regions. The [C II]/CO luminosity ratio of the GRB 980425 host is close to the highest values found for local star-forming galaxies. Indeed, its CO-derived molecular gas mass is low given its SFR and metallicity, but the [C II]-derived molecular gas mass is close to the expected value. Conclusions. The [O I] and H I concentrations and the high radiation field and density close to the GRB position are consistent with the hypothesis of a very recent (at most a few tens of Myr ago) inflow of atomic gas triggering star formation. In this scenario dust has not had time to build up (explaining high line-to-continuum ratios). Such a recent enhancement of star formation activity would indeed manifest itself in high SFRline/SFRcontinuum ratios because the line indicators are sensitive only to recent (≲10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (~100 Myr). Within a sample of 32 other GRB hosts, 20 exhibit SFRline/SFRcontinuum> 1 with a mean ratio of 1.74 ± 0.32. This is consistent with a very recent enhancement of star formation that is common among GRB hosts, so galaxies that have recently experienced inflow of gas may preferentially host stars exploding as GRBs. Therefore GRBs may be used to select a unique sample of galaxies that is suitable for the investigation of recent gas accretion.",
keywords = "dust, extinction, galaxies: individual: ESO 184-G82, galaxies: ISM, galaxies: star formation, submillimeter: galaxies, gamma-ray burst: individual: 980425, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena",
author = "M.~J. Michalowski and {Castro Cer{\'o}n}, J.~M. and J.~L. Wardlow and A. Karska and H. Messias and {van der Werf}, P. and L.~K. Hunt and M. Baes and A.~J. Castro-Tirado and G. Gentile and J. Hjorth and {Le Floc'h}, E. and {P{\'e} rez-Martinez}, R. and {Nicuesa Guelbenzu}, A. and J. Rasmussen and J.~R. Rizzo and A. Rossi and {S{\'a} nchez-Portal}, M. and P. Schady and J. Sollerman and D. Xu",
year = "2016",
month = "11",
day = "1",
doi = "10.1051/0004-6361/201629441",
language = "English",
volume = "595",
pages = "A72",
journal = "Astronomy & Astrophysics",
issn = "0004-6361",
publisher = "Springer Verlag",

}

TY - JOUR

T1 - GRB 980425 host: [C II], [O I], and CO lines reveal recent enhancement of star formation due to atomic gas inflow

AU - Michalowski, M.~J.

AU - Castro Cerón, J.~M.

AU - Wardlow, J.~L.

AU - Karska, A.

AU - Messias, H.

AU - van der Werf, P.

AU - Hunt, L.~K.

AU - Baes, M.

AU - Castro-Tirado, A.~J.

AU - Gentile, G.

AU - Hjorth, J.

AU - Le Floc'h, E.

AU - Pé rez-Martinez, R.

AU - Nicuesa Guelbenzu, A.

AU - Rasmussen, J.

AU - Rizzo, J.~R.

AU - Rossi, A.

AU - Sá nchez-Portal, M.

AU - Schady, P.

AU - Sollerman, J.

AU - Xu, D.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - Context. Accretion of gas from the intergalactic medium is required to fuel star formation in galaxies. We have recently suggested that this process can be studied using host galaxies of gamma-ray bursts (GRBs). Aims. Our aim is to test this possibility by studying in detail the properties of gas in the closest galaxy hosting a GRB (980425). Methods. We obtained the first ever far-infrared (FIR) line observations of a GRB host, namely Herschel/PACS resolved [C II] 158 μm and [O I] 63 μm spectroscopy, and an APEX/SHeFI CO(2–1) line detection and ALMA CO(1–0) observations of the GRB 980425 host. Results. The GRB 980425 host has elevated [C II]/FIR and [O I]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C II], [O I], Hα) than from continuum (UV, IR, radio) indicators. [C II] emission exhibits a normal morphology, peaking at the galaxy centre, whereas [O I] is concentrated close to the GRB position and the nearby Wolf-Rayet region. The high [O I] flux indicates that there is high radiation field and high gas density at these positions, as derived from modelling of photo-dissociation regions. The [C II]/CO luminosity ratio of the GRB 980425 host is close to the highest values found for local star-forming galaxies. Indeed, its CO-derived molecular gas mass is low given its SFR and metallicity, but the [C II]-derived molecular gas mass is close to the expected value. Conclusions. The [O I] and H I concentrations and the high radiation field and density close to the GRB position are consistent with the hypothesis of a very recent (at most a few tens of Myr ago) inflow of atomic gas triggering star formation. In this scenario dust has not had time to build up (explaining high line-to-continuum ratios). Such a recent enhancement of star formation activity would indeed manifest itself in high SFRline/SFRcontinuum ratios because the line indicators are sensitive only to recent (≲10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (~100 Myr). Within a sample of 32 other GRB hosts, 20 exhibit SFRline/SFRcontinuum> 1 with a mean ratio of 1.74 ± 0.32. This is consistent with a very recent enhancement of star formation that is common among GRB hosts, so galaxies that have recently experienced inflow of gas may preferentially host stars exploding as GRBs. Therefore GRBs may be used to select a unique sample of galaxies that is suitable for the investigation of recent gas accretion.

AB - Context. Accretion of gas from the intergalactic medium is required to fuel star formation in galaxies. We have recently suggested that this process can be studied using host galaxies of gamma-ray bursts (GRBs). Aims. Our aim is to test this possibility by studying in detail the properties of gas in the closest galaxy hosting a GRB (980425). Methods. We obtained the first ever far-infrared (FIR) line observations of a GRB host, namely Herschel/PACS resolved [C II] 158 μm and [O I] 63 μm spectroscopy, and an APEX/SHeFI CO(2–1) line detection and ALMA CO(1–0) observations of the GRB 980425 host. Results. The GRB 980425 host has elevated [C II]/FIR and [O I]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C II], [O I], Hα) than from continuum (UV, IR, radio) indicators. [C II] emission exhibits a normal morphology, peaking at the galaxy centre, whereas [O I] is concentrated close to the GRB position and the nearby Wolf-Rayet region. The high [O I] flux indicates that there is high radiation field and high gas density at these positions, as derived from modelling of photo-dissociation regions. The [C II]/CO luminosity ratio of the GRB 980425 host is close to the highest values found for local star-forming galaxies. Indeed, its CO-derived molecular gas mass is low given its SFR and metallicity, but the [C II]-derived molecular gas mass is close to the expected value. Conclusions. The [O I] and H I concentrations and the high radiation field and density close to the GRB position are consistent with the hypothesis of a very recent (at most a few tens of Myr ago) inflow of atomic gas triggering star formation. In this scenario dust has not had time to build up (explaining high line-to-continuum ratios). Such a recent enhancement of star formation activity would indeed manifest itself in high SFRline/SFRcontinuum ratios because the line indicators are sensitive only to recent (≲10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (~100 Myr). Within a sample of 32 other GRB hosts, 20 exhibit SFRline/SFRcontinuum> 1 with a mean ratio of 1.74 ± 0.32. This is consistent with a very recent enhancement of star formation that is common among GRB hosts, so galaxies that have recently experienced inflow of gas may preferentially host stars exploding as GRBs. Therefore GRBs may be used to select a unique sample of galaxies that is suitable for the investigation of recent gas accretion.

KW - dust, extinction, galaxies: individual: ESO 184-G82, galaxies: ISM, galaxies: star formation, submillimeter: galaxies, gamma-ray burst: individual: 980425, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena

U2 - 10.1051/0004-6361/201629441

DO - 10.1051/0004-6361/201629441

M3 - Article

VL - 595

SP - A72

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

ER -