Maqola

GRB 021004: Tomography of a gamma-ray burst progenitor and its host galaxy

A. J. Castro‐TiradoInstituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18.008 Granada, Spain e-mail: [email protected]P. MøllerEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, GermanyGuillermo Garcı́a-SeguraInstituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, Ensenada 22800, Baja California, MéxicoJ. GorosabelInstituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18.008 Granada, Spain e-mail: [email protected]E. PérezInstituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18.008 Granada, Spain e-mail: [email protected]A. de Ugarte PostigoINAF, Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), ItalyE. SolanoLaboratorio de Astrofísica Estelar y Exoplanetas, Dpto. Astrofísica, Centro de Astrobiología (CSIC/INTA), PO Box 78, 28691 Villanueva de la Cañada, Madrid, SpainD. BarradoCalar Alto Observatory, Centro Astronómico Hispano Alemán, C . Jesús Durbán Remón, 2-2, 04004 Almería, SpainS. KloseThüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, GermanyД. А. КаннThüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, GermanyJ. M. Castro CerónEuropean Space Agency (ESA), European Space Astronomy Centre (ESAC), PO Box, Apdo. de correos 78, 28691 Villanueva de la Cañada, Madrid, SpainC. KouveliotouNASA Marshall Space Flight Center, NSSTC, 320 Sparkman Drive, Huntsville, Alabama 35805, USAJ. P. U. FynboDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 København Ø, DenmarkJ. HjorthDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 København Ø, DenmarkH. PedersenDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 København Ø, DenmarkE. PianEuropean Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, GermanyE. RolAstronomical Institute “Anton Pannekoek”, University of Amsterdam, PO number 94249, 1090 GE, Amsterdam, The NetherlandsE. PalazziINAF - IASF di Bologna, via Gobetti 101, 40129 Bologna, ItalyN. MasettiINAF - IASF di Bologna, via Gobetti 101, 40129 Bologna, ItalyN. R. TanvirDepartment of Physics & Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UKP. M. VreeswijkDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 København Ø, DenmarkM. I. AndersenDark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 København Ø, DenmarkA. S. FruchterSpace Telescope Science Institute, 3700 San Martín Dr, Baltimore, MD 21218-2463, USAJ. GreinerMax-Planck-Institut für extraterrestrische Physik, 85748 Garching, GermanyR. A. M. J. WijersAstronomical Institute “Anton Pannekoek”, University of Amsterdam, PO number 94249, 1090 GE, Amsterdam, The NetherlandsE. P. J. van den HeuvelAstronomical Institute “Anton Pannekoek”, University of Amsterdam, PO number 94249, 1090 GE, Amsterdam, The Netherlands

2010en

ABI

Annotatsiya

Aims. We analyse the distribution of matter around the progenitor star of gamma-ray burst GRB 021004 and the properties of its host galaxy with high-resolution echelle and near-infrared spectroscopy.Methods. Observations were taken by the 8.2 m Very Large Telescope with the Ultraviolet and Visual Echelle spectrograph (UVES) and the Infrared Spectrometer And Array Camera (ISAAC) between 10 and 14 h after the onset of the event.Results. We report the first detection of emission lines from a GRB host galaxy in the near-infrared, detecting Hα and the [O III] doublet. These allow us to independently measure the systemic redshift (z = 2.3304 ± 0.0005), which is not contaminated by absorption as the Lyα line is, and infer the host galaxy properties. From the visual echelle spectroscopy, we find several absorption-line groups spanning a range of about 3000 km s-1 in velocity relative to the redshift of the host galaxy. The absorption profiles are very complex with both velocity-broadened components extending over several 100 km s-1 and narrow lines with velocity widths of only ~20 km s-1. By analogy with QSO absorption line studies, the relative velocities, widths, and degrees of ionization of the lines (“line-locking”, “ionization-velocity correlation”) show that the progenitor had both an extremely strong radiation field and several distinct mass-loss phases (winds).Conclusions. These results are consistent with GRB progenitors being massive stars, such as luminous blue variables (LBVs) or Wolf-Rayet stars, providing a detailed picture of the spatial and velocity structure of the GRB progenitor star at the time of explosion. The host galaxy is a prolific star-forming galaxy with a SFR of ~40 yr-1.

Hali tarjima qilinmagan

Identifikatorlar

DOI: 10.1051/0004-6361/200913966

Iqtiboslar va manbalar

2 ta iqtibos0 ta foydalanilgan manba

Koʻrsatkichlar — AkademScholar