A&A 425, L33-L36 (2004)
DOI: 10.1051/0004-6361:200400058
Letter
Massive star-formation rates of
-ray burst host galaxies: An unobscured view in X-rays
D. Watson1, J. Hjorth1, P. Jakobsson1, K. Pedersen1, S. Patel2 and C. Kouveliotou3
1 Niels Bohr Institute, Astronomical Observatory, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark
e-mail: darach@astro.ku.dk
2 USRA (Universities Space Research Association), NSSTC, SD-50, 320 Sparkman Drive, Huntsville, AL 35805, USA
3 NASA Marshall Space Flight Center, NSSTC, SD-50, 320 Sparkman Drive, Huntsville, AL 35805, USA
(Received 12 July 2004 / Accepted 16 August 2004 )
Abstract
The hard X-ray (2-10 keV) luminosity of a star-forming galaxy
tracks its population of high mass X-ray binaries and is
essentially unobscured. It is therefore a practically unbiased
measure of star-formation in the host galaxies of
-ray
bursts (GRBs). Using recent and archival observations of GRBs
with the XMM-Newton and Chandra X-ray observatories, limits are placed
on the underlying X-ray emission from GRB hosts. Useful limits
on the current massive star-formation rates (SFRs), unaffected
by obscuration, are obtained for the hosts of three low
redshift GRBs: GRB 980425, GRB 030329 and GRB 031203. These
limits show that though the specific SFRs may be high (as in
dwarf starburst galaxies), none have massive obscured
star-formation at the levels implied by the sub-mm detection of
some GRB hosts. It is also shown that in cases where the faint
luminosities of the late time afterglow or supernova emission
are of interest, the contribution of the host galaxy to the
X-ray flux may be significant.
Key words: gamma rays: bursts -- X-rays: galaxies -- X-rays: binaries -- galaxies: starburst
SIMBAD Objects
© ESO 2004
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