GRB 050223: A dark GRB in a dusty starburst galaxy
Aims. We aim at detecting and determining the properties of the host galaxy of the dark GRB 050223. Methods. We use VLT optical/NIR images coupled to Swift X-ray positioning, and optical spectra of the host galaxy to measure its properties. Results. We find a single galaxy within the Swift error box...
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| Autores principales: | , , , , , , , , , , , , , , , , , , , , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00046361_v459_n1_pL5_Pellizza |
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| Sumario: | Aims. We aim at detecting and determining the properties of the host galaxy of the dark GRB 050223. Methods. We use VLT optical/NIR images coupled to Swift X-ray positioning, and optical spectra of the host galaxy to measure its properties. Results. We find a single galaxy within the Swift error box of GRB 050223. It is located at z = 0.584 and its luminosity is L ∼ 0.4 L*. Emission lines in the galaxy spectrum imply an intrinsic SFR > 7 M ⊙ yr-1, and a large extinction Av > 2 mag within it. We also detect absorption lines, which reveal an underlying stellar population with an age between 40 Myr and 1.5 Gyr. Conclusions. The identification of a host galaxy with atypical properties using only the X-ray transient suggests that a bias may be present in the former sample of host galaxies. Dust obscuration together with intrinsic faintness are the most probable causes for the darkness of this burst. © ESO 2006. |
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