Details

Autor(en) / Beteiligte

• Cenko, S. B
• Kelemen, J
• Harrison, F. A
• Fox, D. B
• Kulkarni, S. R
• Kasliwal, M. M
• Ofek, E. O
• Rau, A
• Gal-Yam, A
• Frail, D. A
• Moon, D.-S

Titel

Dark Bursts in the Swift Era: The Palomar 60 Inch-Swift Early Optical Afterglow Catalog

Ist Teil von

• The Astrophysical journal, 2009-03, Vol.693 (2), p.1484-1493

Ort / Verlag

Bristol: IOP Publishing

Erscheinungsjahr

2009

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present multicolor optical observations of long-duration g-ray bursts (GRBs) made over a three-year period with the robotic Palomar 60 inch telescope (P60). Our sample consists of all 29 events discovered by Swift for which P60 began observations less than 1 hr after the burst trigger. We were able to recover 80% of the optical afterglows from this prompt sample, and we attribute this high efficiency to our red coverage. Like Melandri et al. (2008), we find that a significant fraction (50%) of Swift events show a suppression of the optical flux with regard to the X-ray emission (the so-called 'dark' bursts). Our multicolor photometry demonstrates this is likely due in large part to extinction in the host galaxy. We argue that previous studies, by selecting only the brightest and best-sampled optical afterglows, have significantly underestimated the amount of dust present in typical GRB environments.