主要内容:
说这个星系看起来很像一个年轻的星系（虽然红移只有0.1），就说可以把它当作红移为7的星系，来研究红移为7的星系。
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文章信息:
- · arXiv e-print (arXiv:1010.1783)
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| Title: |
| A nearby GRB host prototype for z~7 Lyman-break galaxies: Spitzer-IRS and X-shooter spectroscopy of the host galaxy of GRB031203 |
| Authors: |
| Watson, D.; French, J.; Christensen, L.; O'Halloran, B.; Michałowski, M.; Hjorth, J.; Malesani, D.; Fynbo, J. P. U.;Gordon, K. D.; Castro Cerón, J. M. |
| Publication: |
| eprint arXiv:1010.1783 |
| Publication Date: |
| 10/2010 |
| Origin: |
| ARXIV |
| Keywords: |
| Astrophysics - Cosmology and Extragalactic Astrophysics |
| Comment: |
| Submitted to ApJ. 9 pages, 6 figures, emulateapj style |
| Bibliographic Code: |
| 2010arXiv1010.1783W |
Abstract
Gamma-ray burst (GRB) host galaxies have been studied extensively in optical photometry and spectroscopy. Here we present the first mid-infrared spectrum of a GRB host, HG031203. It is one of the nearest GRB hosts at z=0.1055, allowing both low and high-resolution spectroscopy with Spitzer-IRS. Medium resolution UV-to-K-band spectroscopy with the X-shooter spectrograph on the VLT is also presented, along with Spitzer IRAC and MIPS photometry, as well as radio and sub-mm observations. These data allow us to construct a UV-to-radio spectral energy distribution with almost complete spectroscopic coverage from 0.3-35 micron of a GRB host galaxy for the first time, potentially valuable as a template for future model comparisons. The IRS spectra show strong, high-ionisation fine structure line emission indicative of a hard radiation field in the galaxy, suggestive of strong ongoing star-formation and a very young stellar population. The selection of HG031203 via the presence of a GRB suggests that it might be a useful analogue of very young star-forming galaxies in the early universe, and hints that local BCDs may be used as more reliable analogues of star-formation in the early universe than typical local starbursts. We look at the current debate on the ages of the dominant stellar populations in z~7 and z~8 galaxies in this context. The nebular line emission is so strong in HG031203, that at z~7, it can reproduce the spectral energy distributions of z-band dropout galaxies with elevated IRAC 3.6 and 4.5 micron fluxes without the need to invoke a 4000A break.
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