Swift-UVOT detection of GRB 050318

Abstract

We present observations of GRB 050318 by the Ultra-Violet and Optical Telescope (UVOT) on-board the Swift observatory. The data are the first detections of a Gamma Ray Burst (GRB) afterglow decay by the UVOT instrument, launched specifically to open a new window on these transient sources. We showcase UVOTs ability to provide multi-color photometry and the advantages of combining UVOT data with simultaneous and contemporaneous observations from the high-energy detectors on the Swift spacecraft. Multiple filters covering 1,800-6,000 Angstroms reveal a red source with spectral slope steeper than the simultaneous X-ray continuum. Spectral fits indicate that the UVOT colors are consistent with dust extinction by systems at z = 1.2037 and z = 1.4436, redshifts where absorption systems have been pre-identified. However, the data can be most-easily reproduced with models containing a foreground system of neutral gas redshifted by z = 2.8 +/- 0.3. For both of the above scenarios, spectral and decay slopes are, for the most part, consistent with fireball expansion into a uniform medium, provided a cooling break occurs between the energy ranges of the UVOT and Swifts X-ray instrumentation.

15 pages, 4 figures, ApJ Letters, in press

References in corpus (11)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Spectra and Light Curves of Gamma-Ray Burst Afterglows
• Intrinsic spectra and energetics of BeppoSAX Gamma-Ray Bursts with known redshifts
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• Gamma-Ray Bursts: Progress, Problems & Prospects
• The line-of-sight towards GRB 030429 at z = 2.66: Probing the matter at stellar, galactic and intergalactic scales
• Very high column density and small reddening towards GRB 020124 at z = 3.20
• The Afterglows, Redshifts, and Properties of Swift Gamma-Ray Bursts
• Dust Depletion and Extinction in a Gamma-Ray Burst Afterglow
• Swift XRT Observations of the Breaking X-ray Afterglow of GRB 050318

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• A Comprehensive Analysis of the Swift/XRT Data: II. Diverse Physical Origins of the Shallow Decay Segment
• The optically unbiased GRB host (TOUGH) survey. I. Survey design and catalogs
• The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog
• Bulk Lorentz factors of Gamma-Ray Bursts
• Dust and Gas in the Local Environments of Gamma-Ray Bursts
• Dust extinction for an unbiased sample of GRB afterglows
• A unifying view of Gamma Ray Burst Afterglows
• Confirming the gamma-ray burst spectral-energy correlations in the era of multiple time breaks
• Very Early Optical Afterglows of Gamma-Ray Bursts: Evidence for Relative Paucity of Detection
• Phenomenology of Reverse-Shock Emission in the Optical Afterglows of Gamma Ray Bursts
• Gamma-ray burst optical light-curve zoo: comparison with X-ray observations
• Are Swift gamma-ray bursts consistent with the Ghirlanda relation?
• Optical afterglow luminosities in the Swift epoch: confirming clustering and bimodality
• Testing a new view of Gamma Ray Burst Afterglows
• An Estimation of the Gamma-Ray Burst Afterglow Apparent Optical Brightness Distribution Function
• Swift/UVOT: 18 Years of Long GRB Discoveries and Advances