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

被引：25

作者：

Michalowski, M. J. ^{[1
]}

Castro Ceron, J. M. ^{[2
]}

Wardlow, J. L. ^{[3
,4
]}

Karska, A. ^{[5
,6
]}

Messias, H. ^{[7
]}

van der Werf, P. ^{[8
]}

Hunt, L. K. ^{[9
]}

Baes, M. ^{[10
]}

Castro-Tirado, A. J. ^{[11
]}

Gentile, G. ^{[10
,12
]}

Hjorth, J. ^{[3
]}

Le Floc'h, E. ^{[13
]}

Perez-Martinez, R. ^{[14
]}

Guelbenzu, A. Nicuesa ^{[15
]}

Rasmussen, J. ^{[3
,16
]}

Rizzo, J. R. ^{[17
]}

Rossi, A. ^{[18
]}

Sanchez-Portal, M. ^{[2
]}

Schady, P. ^{[19
]}

Sollerman, J. ^{[20
]}

Xu, D. ^{[21
]}

机构：

[1] Univ Edinburgh, Royal Observ, Scottish Univ Phys Alliance, Inst Astron, Blakford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland

[2] Herschel Sci Ctr ESA ESAC, 28-692 Villanueva Canada, Madrid, Spain

[3] Univ Copenhagen, Dark Cosmol Ctr, Niels Bohr Inst, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark

[4] Univ Durham, Dept Phys, Ctr Extragalact Astron, South Rd, Durham DH1 3LE, England

[5] Nicolaus Copernicus Univ, Ctr Astron, Fac Phys Astron & Informat, Grudziadzka 5, PL-87100 Torun, Poland

[6] Adam Mickiewicz Univ, Astron Observ, Sloneczna 36, PL-60268 Poznan, Poland

[7] Univ Lisbon, Ctr Astron & Astrofis, Observ Astron Lisboa, P-1349018 Lisbon, Portugal

[8] Leiden Univ, Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands

[9] INAF Osservatorio Astrofis Arcetri, Largo E Fermi 5, I-50125 Florence, Italy

[10] Univ Ghent, Sterrenkundig Observ, Krijgslaan 281-S9, B-9000 Ghent, Belgium

[11] CSIC, IAA, Glorieta Astron S-N, E-18008 Granada, Spain

[12] Vrije Univ Brussel, Dept Phys & Astrophys, Pl Laan 2, B-1050 Brussels, Belgium

[13] Univ Paris Diderot, Lab AIM Paris Saclay, CEA DSM Irfu, CNRS,CE Saclay, Pt Courrier 131, F-91191 Gif Sur Yvette, France

[14] ESAC ESA, XMM Sci Operat Ctr, Madrid 28692, Spain

[15] Thuringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany

[16] Tech Univ Denmark, Dept Phys, Bldg 309, DK-2800 Lyngby, Denmark

[17] INTA CSIC, Ctr Astrobiol, Ctra M-108,Km 4, Madrid, Spain

[18] INAF IASF Bologna, Via Gobetti 101, I-40129 Bologna, Italy

[19] Max Planck Inst Extraterr Phys, Giessenbachstr, D-85748 Garching, Germany

[20] Stockholm Univ, Oskar Klein Ctr, Dept Astron, AlbaNova, S-10691 Stockholm, Sweden

[21] Chinese Acad Sci, Key Lab Space Astron & Technol, Natl Astron Observ, 20A Datun Rd, Beijing 100012, Peoples R China

来源：

ASTRONOMY & ASTROPHYSICS | 2016年 / 595卷

基金：

新加坡国家研究基金会; 英国科学技术设施理事会;

关键词：

dust; extinction; galaxies: individual: ESO 184-G82; galaxies: ISM; galaxies: star formation; submillimeter: galaxies; gamma-ray burst: individual: 980425; GAMMA-RAY BURST; VLT/X-SHOOTER SPECTROSCOPY; SWIFT/BAT6 COMPLETE SAMPLE; FAR-INFRARED SPECTROSCOPY; LOW-METALLICITY STARBURST; SIMILAR-TO; FORMATION RATES; SUBMILLIMETER GALAXIES; STELLAR MASSES; MOLECULAR-HYDROGEN;

D O I：

10.1051/0004-6361/201629441

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

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 mu m and [O I] 63 mu m spectroscopy, and an APEX/SHeFI CO(2-1) line detection and ALMA CO(1-0) observations of the GRB980425 host. Results. The GRB980425 host has elevated [CII]/FIR and [O I]/FIR ratios and higher values of star formation rates (SFR) derived from line ([C II], [O I], H alpha) 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 GRB980425 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 (less than or similar to 10 Myr) activity, whereas the continuum indicators measure the SFR averaged over much longer periods (similar to 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.

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页数：14