학술논문
Late time observations of GRB080319B: jet break, host galaxy and accompanying supernova
Document Type
Working Paper
Author
Tanvir, Nial R.; Rol, Evert; Levan, Andrew; Fruchter, Andrew; Granot, Jonathan; Svensson, Karl M.; O'Brien, Paul T.; Wiersema, Klaas; Starling, Rhaana L. C.; Jakobsson, Pall; Fynbo, Johan; Hjorth, Jens; Curran, Peter; van der Horst, Alexander J.; Kouveliotou, Chryssa; Racusin, Judith L.; Burrows, David N.; Genet, Frank
Source
Astrophys.J.725:625-632,2010
Subject
Language
Abstract
The Swift discovered GRB080319B was by far the most distant source ever observed at naked eye brightness, reaching a peak apparent magnitude of 5.3 at a redshift of z=0.937. We present our late-time optical (HST, Gemini & VLT) and X-ray (Chandra) observations, which confirm that an achromatic break occurred in the power-law afterglow light curve at ~11 days post-burst. This most likely indicates that the gamma-ray burst (GRB) outflow was collimated, which for a uniform jet would imply a total energy in the jet E_{jet} \gsim 10^{52} erg. Our observations also show a late-time excess of red light, which is well explained if the GRB was accompanied by a supernova (SN), similar to those seen in some other long-duration GRBs. The latest observations are dominated by light from the host and show that the GRB took place in a faint dwarf galaxy (r(AB)\approx27.0, rest-frame M_B\approx-17.2). This galaxy is small even by the standards of other GRB hosts, which is suggestive of a low metallicity environment. Intriguingly, the properties of this extreme event - a small host and bright supernova - are entirely typical of the very low-luminosity bursts such as GRB980425 and GRB060218.
Comment: Revised in response to referee's comments, and with some additional data added
Comment: Revised in response to referee's comments, and with some additional data added