Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy

K. E. Heintz, C. Ledoux, J. P. U. Fynbo, P. Jakobsson, P. Noterdaeme, J.-K. Krogager, J. Bolmer, P. Møller, S. D. Vergani, D. Watson, T. Zafar, A. De Cia, N. R. Tanvir, D. B. Malesani, J. Japelj, S. Covino, L. Kaper

Research output: Contribution to journalJournal articleResearchpeer-review

19 Downloads (Pure)

Abstract

We present a survey for neutral atomic-carbon (C I) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host galaxies at high redshift. We compile a sample of 29 medium- to high-resolution GRB optical afterglow spectra spanning a redshift range through most of cosmic time from 1 <  z <  6. We find that seven (≈25%) of the GRBs entering our statistical sample have C I detected in absorption. It is evident that there is a strong excess of cold gas in GRB hosts compared to absorbers in quasar sightlines. We investigate the dust properties of the GRB C I absorbers and find that the amount of neutral carbon is positively correlated with the visual extinction, AV, and the strength of the 2175 Å dust extinction feature, Abump. GRBs with C I detected in absorption are all observed above a certain threshold of logN(H I)/cm−2 + [X/H] > 20.7 and a dust-phase iron column density of logN(Fe)dust/cm−2 > 16.2. In contrast to the SED-derived dust properties, the strength of the C I absorption does not correlate with the depletion-derived dust properties. This indicates that the GRB C I absorbers trace dusty systems where the dust composition is dominated by carbon-rich dust grains. The observed higher metal and dust column densities of the GRB C I absorbers compared to H2- and C I-bearing quasar absorbers is mainly a consequence of how the two absorber populations are selected, but is also required in the presence of intense UV radiation fields in actively star-forming galaxies.
Original languageEnglish
Article numberA20
JournalAstronomy & Astrophysics
Volume621
Number of pages13
ISSN0004-6361
DOIs
Publication statusPublished - 2019

Keywords

  • Gamma-ray burst: general
  • Galaxies: ISM
  • Galaxies: high-redshift
  • Dust
  • Extinction

Cite this

Heintz, K. E. ; Ledoux, C. ; Fynbo, J. P. U. ; Jakobsson, P. ; Noterdaeme, P. ; Krogager, J.-K. ; Bolmer, J. ; Møller, P. ; Vergani, S. D. ; Watson, D. ; Zafar, T. ; De Cia, A. ; Tanvir, N. R. ; Malesani, D. B. ; Japelj, J. ; Covino, S. ; Kaper, L. / Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy. In: Astronomy & Astrophysics. 2019 ; Vol. 621.
@article{c0080c6cedd9434eb04e454441dbcd89,
title = "Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy",
abstract = "We present a survey for neutral atomic-carbon (C I) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host galaxies at high redshift. We compile a sample of 29 medium- to high-resolution GRB optical afterglow spectra spanning a redshift range through most of cosmic time from 1 <  z <  6. We find that seven (≈25{\%}) of the GRBs entering our statistical sample have C I detected in absorption. It is evident that there is a strong excess of cold gas in GRB hosts compared to absorbers in quasar sightlines. We investigate the dust properties of the GRB C I absorbers and find that the amount of neutral carbon is positively correlated with the visual extinction, AV, and the strength of the 2175 {\AA} dust extinction feature, Abump. GRBs with C I detected in absorption are all observed above a certain threshold of logN(H I)/cm−2 + [X/H] > 20.7 and a dust-phase iron column density of logN(Fe)dust/cm−2 > 16.2. In contrast to the SED-derived dust properties, the strength of the C I absorption does not correlate with the depletion-derived dust properties. This indicates that the GRB C I absorbers trace dusty systems where the dust composition is dominated by carbon-rich dust grains. The observed higher metal and dust column densities of the GRB C I absorbers compared to H2- and C I-bearing quasar absorbers is mainly a consequence of how the two absorber populations are selected, but is also required in the presence of intense UV radiation fields in actively star-forming galaxies.",
keywords = "Gamma-ray burst: general, Galaxies: ISM, Galaxies: high-redshift, Dust, Extinction",
author = "Heintz, {K. E.} and C. Ledoux and Fynbo, {J. P. U.} and P. Jakobsson and P. Noterdaeme and J.-K. Krogager and J. Bolmer and P. M{\o}ller and Vergani, {S. D.} and D. Watson and T. Zafar and {De Cia}, A. and Tanvir, {N. R.} and Malesani, {D. B.} and J. Japelj and S. Covino and L. Kaper",
year = "2019",
doi = "10.1051/0004-6361/201834246",
language = "English",
volume = "621",
journal = "Astronomy & Astrophysics",
issn = "0004-6361",
publisher = "E D P Sciences",

}

Heintz, KE, Ledoux, C, Fynbo, JPU, Jakobsson, P, Noterdaeme, P, Krogager, J-K, Bolmer, J, Møller, P, Vergani, SD, Watson, D, Zafar, T, De Cia, A, Tanvir, NR, Malesani, DB, Japelj, J, Covino, S & Kaper, L 2019, 'Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy', Astronomy & Astrophysics, vol. 621, A20. https://doi.org/10.1051/0004-6361/201834246

Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy. / Heintz, K. E.; Ledoux, C.; Fynbo, J. P. U.; Jakobsson, P.; Noterdaeme, P.; Krogager, J.-K.; Bolmer, J.; Møller, P.; Vergani, S. D.; Watson, D.; Zafar, T.; De Cia, A.; Tanvir, N. R.; Malesani, D. B.; Japelj, J.; Covino, S.; Kaper, L.

In: Astronomy & Astrophysics, Vol. 621, A20, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Cold gas in the early Universe - Survey for neutral atomic-carbon in GRB host galaxies at 1 < z< 6 from optical afterglow spectroscopy

AU - Heintz, K. E.

AU - Ledoux, C.

AU - Fynbo, J. P. U.

AU - Jakobsson, P.

AU - Noterdaeme, P.

AU - Krogager, J.-K.

AU - Bolmer, J.

AU - Møller, P.

AU - Vergani, S. D.

AU - Watson, D.

AU - Zafar, T.

AU - De Cia, A.

AU - Tanvir, N. R.

AU - Malesani, D. B.

AU - Japelj, J.

AU - Covino, S.

AU - Kaper, L.

PY - 2019

Y1 - 2019

N2 - We present a survey for neutral atomic-carbon (C I) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host galaxies at high redshift. We compile a sample of 29 medium- to high-resolution GRB optical afterglow spectra spanning a redshift range through most of cosmic time from 1 <  z <  6. We find that seven (≈25%) of the GRBs entering our statistical sample have C I detected in absorption. It is evident that there is a strong excess of cold gas in GRB hosts compared to absorbers in quasar sightlines. We investigate the dust properties of the GRB C I absorbers and find that the amount of neutral carbon is positively correlated with the visual extinction, AV, and the strength of the 2175 Å dust extinction feature, Abump. GRBs with C I detected in absorption are all observed above a certain threshold of logN(H I)/cm−2 + [X/H] > 20.7 and a dust-phase iron column density of logN(Fe)dust/cm−2 > 16.2. In contrast to the SED-derived dust properties, the strength of the C I absorption does not correlate with the depletion-derived dust properties. This indicates that the GRB C I absorbers trace dusty systems where the dust composition is dominated by carbon-rich dust grains. The observed higher metal and dust column densities of the GRB C I absorbers compared to H2- and C I-bearing quasar absorbers is mainly a consequence of how the two absorber populations are selected, but is also required in the presence of intense UV radiation fields in actively star-forming galaxies.

AB - We present a survey for neutral atomic-carbon (C I) along gamma-ray burst (GRB) sightlines, which probes the shielded neutral gas-phase in the interstellar medium (ISM) of GRB host galaxies at high redshift. We compile a sample of 29 medium- to high-resolution GRB optical afterglow spectra spanning a redshift range through most of cosmic time from 1 <  z <  6. We find that seven (≈25%) of the GRBs entering our statistical sample have C I detected in absorption. It is evident that there is a strong excess of cold gas in GRB hosts compared to absorbers in quasar sightlines. We investigate the dust properties of the GRB C I absorbers and find that the amount of neutral carbon is positively correlated with the visual extinction, AV, and the strength of the 2175 Å dust extinction feature, Abump. GRBs with C I detected in absorption are all observed above a certain threshold of logN(H I)/cm−2 + [X/H] > 20.7 and a dust-phase iron column density of logN(Fe)dust/cm−2 > 16.2. In contrast to the SED-derived dust properties, the strength of the C I absorption does not correlate with the depletion-derived dust properties. This indicates that the GRB C I absorbers trace dusty systems where the dust composition is dominated by carbon-rich dust grains. The observed higher metal and dust column densities of the GRB C I absorbers compared to H2- and C I-bearing quasar absorbers is mainly a consequence of how the two absorber populations are selected, but is also required in the presence of intense UV radiation fields in actively star-forming galaxies.

KW - Gamma-ray burst: general

KW - Galaxies: ISM

KW - Galaxies: high-redshift

KW - Dust

KW - Extinction

U2 - 10.1051/0004-6361/201834246

DO - 10.1051/0004-6361/201834246

M3 - Journal article

VL - 621

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

M1 - A20

ER -