HST Observations of the Host Galaxy of GRB970508

Abstract

We report on observations of the field of GRB~970508 made in early August 1998, 454 days after outburst, with the STIS CCD camera onboard the Hubble Space Telescope. The images, taken in open filter (50CCD) mode, clearly reveal the presence of a galaxy which was obscured in earlier (June 1997) HST images by emission from the optical transient (OT). The galaxy is regular in shape: after correcting for the HST/STIS PSF, it is well-fitted by an exponential disk with a scale length of 0."046 +/- 0."006 and an ellipticity of 0.70 +/- 0.07. All observations are marginally consistent with a continuous decline in OT emission as t^{-1.3} beginning two days after outburst; however, we find no direct evidence in the image for emission from the OT, and the surface brightness profile of the galaxy is most regular if we assume that the OT emission is negligible, suggesting that the OT may have faded more rapidly at late times than is predicted by the power-law decay. Due to the wide bandwidth of the STIS clear mode, the estimated magnitude of the galaxy is dependent on the galaxy spectrum that is assumed. Using colors obtained from late-time ground-based observations to constrain the spectrum, we find V = 25.4 +/- 0.15, a few tenths of a magnitude brighter than earlier ground-based estimates that were obtained by observing the total light of the galaxy and the OT and then subtracting the estimated OT brightness assuming it fades as a single power-law. This again suggests that the OT may have faded faster at late time than the power-law predicts. The position of the OT agrees with that of the isophotal center of the galaxy to 0."01. This remarkable agreement raises the possibility that the GRB may have been associated with either an active galactic nucleus or a nuclear starburst.

Submitted to the Astrophysical Journal (Letters). Thirteen pages, three encapsulated figures. Abstract slightly abridged

References in corpus (32)

• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• Unveiling Dust-enshrouded Star Formation in the Early Universe: a Sub-mm Survey of the Hubble Deep Field
• Optical and Long Wavelength Afterglow from Gamma-Ray Bursts
• The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry
• The Dynamics and Light Curves of Beamed Gamma Ray Burst Afterglows
• Dusty star forming galaxies at high redshift
• Shocked by GRB 970228: the afterglow of a cosmological fireball
• Physical parameters of GRB 970508 and GRB 971214 from their afterglow synchrotron emission
• The history of star formation in dusty galaxies
• Infared Observations of Nebular Emission Lines from Galaxies at z = 3
• Dust sublimation by GRBs and its implications
• Radio Transients from Gamma-Ray Bursters
• A 450-day light curve of the radio afterglow of GRB 970508: Fireball calorimetry
• The Panchromatic Starburst Intensity Limit At Low And High Redshift
• HST and Palomar Imaging of GRB 990123: Implications for the Nature of Gamma-Ray Bursts and their Hosts
• The optical counterpart to gamma-ray burst GRB970228 observed using the Hubble Space Telescope
• The Spatial Distribution of Coalescing Neutron Star Binaries: Implications for Gamma-Ray Bursts
• Implications of the radio afterglow from the gamma-ray burst of May 8, 1997
• The Host Galaxy of GRB 970508
• The radio to X-ray spectrum of GRB 970508 on May 21.0 UT
• The Evolution of Dust Opacity in Galaxies
• A novel image reconstruction method applied to deep Hubble Space Telescope Images
• The Fading Optical Counterpart of GRB~970228, Six Months and One Year Later
• Optical follow-up of GRB 970508
• The Discovery and Broad-band Follow-up of the Transient Afterglow of GRB 980703
• Evidence for Diverse Optical Emission from Gamma-Ray Burst Sources
• The faint-galaxy hosts of gamma-ray bursts
• The Host Galaxy of GRB 990123
• Hubble Space Telescope Imaging of the Optical Transient Associated with GRB970508
• The 1.4 GHz light curve of GRB 970508
• The Host Galaxy of the Gamma--Ray Burst 971214
• Gamma Ray Burst Beaming Constraints from Afterglow Light Curves: GRB 970508

Cited by in corpus (16)

• The Supernova -- Gamma-Ray Burst Connection
• Are the hosts of Gamma-Ray Bursts sub-luminous and blue galaxies?
• The Diversity of Gamma-Ray Bursts and the Surroundings of Massive Stars
• The line-of-sight towards GRB 030429 at z = 2.66: Probing the matter at stellar, galactic and intergalactic scales
• The submm properties of GRB host galaxies
• Probing the cosmic star formation using long Gamma-Ray Bursts: New constraints from the Spitzer Space Telescope
• On the optical and X-ray afterglows of gamma ray bursts
• Are Starburst Galaxies the Hosts of Gamma-Ray Bursts ?
• Gamma-ray bursts: optical afterglows in the deep Newtonian phase
• Gamma-Ray Burst Selected High Redshift Galaxies: Comparison to Field Galaxy Populations to z~3
• Hubble Space Telescope and Ground-Based Optical and Ultraviolet Observations of GRB010222
• BeppoSAX confirmation of beamed afterglow emission from GRB990510
• A Late-Time Flattening of Afterglow Light Curves
• The Host Galaxy of GRB 990712
• Modelling the luminosity function of long Gamma Ray Bursts using SWIFT and FERMI
• Numerical counterparts of GRB host galaxies