The optical afterglow and host galaxy of GRB 000926

We present the discovery of the Optical Transient (OT) of the long{duration gamma-ray burst GRB 000926. The optical transient was detected independently with the Nordic Optical Telescope and at Calar Alto 22.2 hours after the burst. At this time the magnitude of the transient was R =1 9:36. The transient faded with ad ecay slope of about 1:7 during the rst two days after which the slope increased abruptly (within a few hours) to about 2:4. The light-curve started to flatten o after about a week indicating the presence of an underlying extended object. This object was detected in a deep image obtained one month after the GRB at R =2 3:87 0:15 and consists of several compact knots within about 5 arcsec. One of the knots is spatially coin- cident with the position of the OT and hence most likely belongs to the host galaxy. Higher resolution imaging is needed to resolve whether all the compact knots belong to the host galaxy or to several independent objects. In a separate paper we present a discussion of the optical spectrum of the OT, and its inferred redshift (Mller et al., in prep.).

[1]  D. Whittet,et al.  Dust in the Galactic Environment , 2018 .

[2]  L. A. Antonelli,et al.  Discovery of an X-ray afterglow associated with the γ-ray burst of 28 February 1997 , 1997, Nature.

[3]  C. Steidel,et al.  An Imaging and Spectroscopic Study of the z=3.38639 Damped Lyman Alpha System in Q0201+1120: Clues to Star Formation Rate at High Redshift , 2000, astro-ph/0010427.

[4]  Z. G. Dai,et al.  The afterglow of GRB 990123 and a dense medium , 1999 .

[5]  W. Baade,et al.  Spectrophotometric Investigations of Some o- and B-Type Stars Connected with the Orion Nebula , 1937 .

[6]  M. Giavalisco,et al.  Infrared Observations of Nebular Emission Lines from Galaxies at z ≃ 3 , 1998, astro-ph/9806219.

[7]  Jean-Paul Kneib,et al.  The diversity of SCUBA-selected galaxies , 2000 .

[8]  M. Dickinson,et al.  Spectroscopic Confirmation of a Population of Normal Star-forming Galaxies at Redshifts z > 3* , 1996 .

[9]  C. Foltz,et al.  The Large Bright QSO Survey for Damped LY alpha Absorption Systems , 1995 .

[10]  M. I. Andersen,et al.  The Jet and Circumburst Stellar Wind of GRB 980519 , 2000, astro-ph/0007320.

[11]  Takashi Ichikawa,et al.  GALAXY COLORS IN VARIOUS PHOTOMETRIC BAND SYSTEMS , 1995 .

[12]  Stephen J. Warren,et al.  HST images of a galaxy group at z = 2.81, and the sizes of damped Lyα galaxies , 1998 .

[13]  M. Rees,et al.  GRB 990123: reverse and internal shock flashes and late afterglow behaviour , 1999 .

[14]  Y. Pei,et al.  Interstellar dust from the Milky Way to the Magellanic Clouds , 1992 .

[15]  A. Efstathiou,et al.  Starburst galaxies and structure in the submillimetre background towards the Hubble Deep Field , 1999, astro-ph/9912231.

[16]  Donald Q. Lamb,et al.  Gamma-Ray Bursts as a Probe of the Very High Redshift Universe , 2000 .

[17]  J. Rhoads.  The Dynamics and Light Curves of Beamed Gamma-Ray Burst Afterglows , 1999, astro-ph/9903399.

[18]  C. C. Steidel,et al.  Multiwavelength Observations of Dusty Star Formation at Low and High Redshift , 2000, astro-ph/0001126.

[19]  Discovery of 9 ly alpha emitters at redshift Z 3.1 using narrow-band imaging and vlt spectroscopy , 2000, astro-ph/0001156.

[20]  STAR FORMATION IN GALAXIES ALONG THE HUBBLE SEQUENCE , 1998, astro-ph/9807187.

[21]  J. Dunlop,et al.  High-redshift star formation in the Hubble Deep Field revealed by a submillimetre-wavelength survey , 1998, Nature.

[22]  P. Stetson.  DAOPHOT: A COMPUTER PROGRAM FOR CROWDED-FIELD STELLAR PHOTOMETRY , 1987 .

[23]  T. Piran,et al.  Spectra and Light Curves of Gamma-Ray Burst Afterglows , 1997, astro-ph/9712005.

[24]  M. Giavalisco,et al.  Lyα Imaging of a Proto-Cluster Region at ⟨z⟩ = 3.09 , 1999, astro-ph/9910144.

[25]  Mark Dickinson.  The first galaxies: structure and stellar populations , 2000, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[26]  S. G. Djorgovski,et al.  Identification of a galaxy responsible for a high-redshift Lyman-α absorption system , 1996, Nature.

[27]  C. Kouveliotou,et al.  Transient optical emission from the error box of the γ-ray burst of 28 February 1997 , 1997, Nature.

[28]  F T Nichols,et al.  Unfunded research? I am shocked, shocked! , 1993, JAMA.

[29]  S. Djorgovski,et al.  Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997 , 1997, Nature.

[30]  P. Moller,et al.  Extended Lyα emission from a damped Ly α absorber at z=1.93, and the relation between damped Ly α absorbers and Lyman-break galaxies , 1998, astro-ph/9812434.

[31]  I. Smail,et al.  A Deep Submillimeter Survey of Lensing Clusters: A New Window on Galaxy Formation and Evolution , 1997, astro-ph/9708135.

[32]  C. Guidorzi,et al.  Detection of the optical afterglow of GRB 000630: Implications for dark bursts , 2001, astro-ph/0101425.

[33]  D. Schlegel,et al.  Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds , 1997, astro-ph/9710327.

[34]  E. Deutsch.  Empirical Uncertainty Estimators for Astrometry from Digital Databases , 1999, astro-ph/9906177.

[35]  D. Schlegel,et al.  Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds , 1998 .

[36]  E. Waxman,et al.  On the Energy of Gamma-Ray Bursts , 1999, astro-ph/9912214.