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The afterglow and the host galaxy of GRB 011211

P. JakobssonAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkJ. HjorthAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkJ. P. U. FynboAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkJ. GorosabelIAA-CSIC, PO Box 03004, 18080 Granada, SpainK. PedersenAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkI. BurudSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAA. J. LevanDepartment of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UKC. KouveliotouNSSTC, SD-50, 320 Sparkman Drive, Huntsville, Alabama 35805, USAN. R. TanvirDepartment of Physical Sciences, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB, UKA. S. FruchterSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAJames E. RhoadsSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAT. GravInstitute of Theoretical Astrophysics, University of Oslo, PB 1029 Blindern, 05315 Oslo, NorwayMorten W. HansenInstitute of Theoretical Astrophysics, University of Oslo, PB 1029 Blindern, 05315 Oslo, NorwayR. MichelsenAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkM. I. AndersenAstrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, GermanyB. L. JensenAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkH. PedersenAstronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, DenmarkB. ThomsenDepartment of Physics and Astronomy, University of Aarhus, Ny Munkegade, 8000 Århus C, DenmarkM. WeidingerDepartment of Physics and Astronomy, University of Aarhus, Ny Munkegade, 8000 Århus C, DenmarkS. G. BhargaviIndian Institute of Astrophysics, Sarjapur Road, Bangalore 560 034, IndiaR. CowsikIndian Institute of Astrophysics, Sarjapur Road, Bangalore 560 034, IndiaS. B. PandeyState Observatory, Manora Peak, Nainital 263 129, India

2003en

ABI

Annotatsiya

We present optical, near-infrared, and X-ray observations of the optical afterglow (OA) of the X-ray rich, long-duration gamma-ray burst GRB 011211. Hubble Space Telescope (HST) data obtained 14, 26, 32, and 59 days after the burst, show the host galaxy to have a morphology that is fairly typical of blue galaxies at high redshift. We measure its magnitude to be . We detect a break in the OA R-band light curve which is naturally accounted for by a collimated outflow geometry. By fitting a broken power-law to the data we find a best fit with a break days after the burst, a pre-break slope of , and a post-break slope of . The UV-optical spectral energy distribution (SED) around 14 hours after the burst is best fit with a power-law with index reddened by an SMC-like extinction law with a modest mag. By comparison, from the XMM-Newton X-ray data at around the same time, we find a decay index of and a spectral index of . Interpolating between the UV-optical and X-ray implies that the cooling frequency is located close to ~1016 Hz in the observer frame at the time of the observations. We argue, using the various temporal and spectral indices above, that the most likely afterglow model is that of a jet expanding into an external environment that has a constant mean density rather than a wind-fed density structure. We estimate the electron energy index for this burst to be .

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Identifikatorlar

DOI: 10.1051/0004-6361:20031044

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