NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
GRB070125: The First Long-Duration Gamma-Ray Burst in a Halo EnvironmentWe present the discovery and high signal-to-noise spectroscopic observations of the optical afterglow of the long-duration gamma-ray burst GRB070125. Unlike all previously observed long-duration afterglows in the redshift range 0.5 < z < 2.0, we find no strong (rest-frame equivalent width W > 1.0 A) absorption features in the wavelength range 4000 - 10000 A. The sole significant feature is a weak doublet we identify as Mg 11 2796 (W = 0.18 +/- 0.02 A), 2803 (W = 0.08 +0I.-01 ) at z = 1.5477 +/- 0.0001. The low observed Mg II and inferred H I column densities are typically observed in galactic halos, far away from the bulk of massive star formation. Deep ground-based imaging reveals no host directly underneath the afterglow to a limit of R > 25.4 mag. Either of the two nearest blue galaxies could host GRB070125; the large offset (d >= 27 kpc) would naturally explain the low column density. To remain consistent with the large local (i.e. parsec scale) circum-burst density inferred from broadband afterglow observations, we speculate GRB070125 may have occurred far away from the disk of its host in a compact star-forming cluster. Such distant stellar clusters, typically formed by dynamical galaxy interactions, have been observed in the nearby universe, and should be more prevalent at z>l where galaxy mergers occur more frequently.
Document ID
20090007967
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Bradley, Cenko S.
(California Inst. of Tech. Pasadena, CA, United States)
Fox, Derek B.
(Pennsylvania State Univ. University Park, PA, United States)
Penprase, Brian E.
(Pomona Coll. Claremont, CA, United States)
Kulkarni, Shri R.
(Pennsylvania State Univ. University Park, PA, United States)
Price, Paul A.
(Hawaii Univ. Honolulu, HI, United States)
Berger, Edo
(Carnegie Institution of Washington Pasadena, CA, United States)
Kulkarni, Shri R.
(California Inst. of Tech. Pasadena, CA, United States)
Harrison, Fiona A.
(California Inst. of Tech. Pasadena, CA, United States)
Gal-Yam, Avishay
(Weizmann Inst. of Science Rehovot, Israel)
Ofek, Eran O.
(California Inst. of Tech. Pasadena, CA, United States)
Rau, Arne
(California Inst. of Tech. Pasadena, CA, United States)
Chandra, Poonam
(National Radio Astronomy Observatory Charlottesville, VA, United States)
Frail, Dale A.
(National Radio Astronomy Observatory Socorro, NM, United States)
Kasliwal, Mansi M.
(California Inst. of Tech. Pasadena, CA, United States)
Schmidt, Brian P.
(Australian National Univ. Weston Creek, Australia)
Soderberg, Alicia M.
(California Inst. of Tech. Pasadena, CA, United States)
Cameron, P. Brian
(California Inst. of Tech. Pasadena, CA, United States)
Roth, Kathy C.
(Gemini Observatory Hilo, HI, United States)
Date Acquired
August 24, 2013
Publication Date
December 17, 2007
Publication Information
Publication: The Astrophysical Journal
Publisher: American Astronomical Society
Volume: 677
Issue: 1
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NNG06GH61G
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available