Issue |
A&A
Volume 372, Number 2, June III 2001
|
|
---|---|---|
Page(s) | 438 - 455 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20010512 | |
Published online | 15 June 2001 |
Host galaxies of gamma-ray bursts: Spectral energy distributions and internal extinction
1
Special Astrophysical Observatory of R.A.S., Karachai-Cherkessia, Nizhnij Arkhyz, 369167 Russia
2
Isaac Newton Institute of Chile, SAO Branch
3
Instituto de Astrofísica de Andalucía (IAA-CSIC), PO Box 03004, 18080 Granada, Spain
4
Laboratorio de Astrofísica Espacial y Física Fundamental (LAEFF-INTA), PO Box 50727, 28080 Madrid, Spain
5
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
6
Institute of Physics, Rostov University, Stachki 194, Rostov-on-Don, 344090, Russia
Corresponding author: V. V. Sokolov, sokolov@sao.ru
Received:
26
February
2001
Accepted:
21
March
2001
We present broad-band flux spectra for the
host galaxies of GRB 970508, GRB 980613, GRB 980703, GRB 990123 and
GRB 991208 obtained with the 6-m telescope of SAO RAS.
The comparison of the broad-band flux spectra of these host galaxies with the
template spectral energy distributions (SEDs) of local starburst galaxies of
different morphological types shows that the
of the hosts
are best fitted by the spectral properties of template SEDs of
starburst galaxies and that there is a significant internal extinction
in these host galaxies.
We derived the absolute magnitudes
of the GRB host galaxies making use of SEDs for the starburst galaxies.
To create theoretical templates we performed the population synthesis modeling
of the continuum spectral
energy distribution of the host galaxies of GRB 970508 and GRB 980703 using
different extinction laws (Cardelli et al. [CITE] and
Calzetti et al. [CITE]) and
assuming burst and exponential scenarios of star formation.
The comparison of
broad-band flux spectra
with the
local starburst galaxies templates and theoretical templates as well as direct
estimates (using Balmer emission lines) of the internal extinction
shows that it is likely to be of great importance
to take into account effects of the internal extinction in the host galaxies.
From the energy distribution in the spectrum of the host galaxy of
GRB 991208 and from the intensity of their spectral lines
(with allowance for the effects of internal extinction) it
follows that this is a GRB galaxy with the highest
massive star-formation rate of all known GRB
galaxies -up to hundreds of solar masses per year.
The reduced luminosity of these dusty galaxies (e.g. for the host of GRB 970508
mag, for the host of GRB 980703
mag
and for the host of GRB 991208
mag)
could explain the observational fact (it results independently from our
photometry and from calculated spectral distribution for the subset of galaxies
having been observed with the 6-m telescope):
none of the observed GRB host galaxies with known distances is
brighter than the local galaxies with the luminosity
(where
is the "knee" of the local luminosity function).
Key words: galaxies: starburst / galaxies: photometry / cosmology: observations / gamma rays: bursts / ISM: dust, extintion
© ESO, 2001
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