We report on multi-band (UBVRIZJsKs) observations of the host galaxy of the April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical and synthetic spectral templates. We find that: (i) the best SED fit is obtained with a starburst template, (ii) the photometric redshift is consistent with the spectroscopic redshift, (iii) the colours of the host are inconsistent with an old stellar population, and (iv) the global extinction is constrained to be in the range AV=0.12-0.61 mag. The derived global extinction agrees with the one reported for the afterglow (AV = 0.4-0.9 mag), suggesting a homogeneous distribution of the interstellar medium (ISM) in the host galaxy. These findings are supplemented by morphological information from Hubble Space Telescope (HST) imaging: the surface brightness profile is smooth, symmetric and compact with no underlying structures (like dust lanes, spiral arms or disks). A natural scenario which accounts of all the above results is a nuclear starburst that harbours a young population of stars from which the GRB originated. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Norway, and Sweden. Based on observations collected at the European Southern Observatory, in La Silla and Paranal (Chile), ESO Large Programmes 165.H-0464(I) and 265.D-5742(C), granted to the GRACE Team. Based on public data collected under ESO programme 67.B-0611(A), and retrieved from ESO data archive. Based on HST data collected under programme 8189.

The blue host galaxy of the red GRB 000418

FRONTERA, Filippo;
2003

Abstract

We report on multi-band (UBVRIZJsKs) observations of the host galaxy of the April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical and synthetic spectral templates. We find that: (i) the best SED fit is obtained with a starburst template, (ii) the photometric redshift is consistent with the spectroscopic redshift, (iii) the colours of the host are inconsistent with an old stellar population, and (iv) the global extinction is constrained to be in the range AV=0.12-0.61 mag. The derived global extinction agrees with the one reported for the afterglow (AV = 0.4-0.9 mag), suggesting a homogeneous distribution of the interstellar medium (ISM) in the host galaxy. These findings are supplemented by morphological information from Hubble Space Telescope (HST) imaging: the surface brightness profile is smooth, symmetric and compact with no underlying structures (like dust lanes, spiral arms or disks). A natural scenario which accounts of all the above results is a nuclear starburst that harbours a young population of stars from which the GRB originated. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Norway, and Sweden. Based on observations collected at the European Southern Observatory, in La Silla and Paranal (Chile), ESO Large Programmes 165.H-0464(I) and 265.D-5742(C), granted to the GRACE Team. Based on public data collected under ESO programme 67.B-0611(A), and retrieved from ESO data archive. Based on HST data collected under programme 8189.
2003
Gorosabel, J.; Klose, S.; Christensen, L.; Fynbo, J. P. U.; Hjorth, J.; Greiner, J.; Tanvir, N.; Jensen, B. L.; Pedersen, H.; Holland, S. T.; Frontera, Filippo; F., AND COAUTHORS
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1202264
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