Please use this identifier to cite or link to this item:
|Title:||The dust-scattered X-ray halo around Swift GRB 050724|
Osborne, J. P.
Goad, M. R.
Beardmore, A. P.
O'Brien, P. T.
Page, K. L.
Supper, M. A.
Burrows, D. N.
|Publisher:||American Astronomical Society, IOP Publishing|
|Citation:||Astrophysical Journal Letters, 2006, 639 (1 I), pp. 323-330|
|Abstract:||This paper discusses the X-ray halo around the Swift -ray burst GRB 050724 (z = 0.258), detected by the Swift X-Ray Telescope. The halo, which forms a ring around the fading X-ray source, expands to a radius of 200" within 8 ks of the burst, exactly as expected for small-angle X-ray scattering by Galactic dust along the line of sight to a cosmologically distant GRB. The expansion curve and radial profile of the halo constrain the scattering dust to be concentrated at a distance of D = 139 +/- 9 pc (from Earth) in a cloud/sheet of thickness Delta D < 22 pc. The halo was observed only out to scattering angles of 200", for which the scattering is dominated by the largest grains, with a maximum size estimated to be amax ~= 0.4 - 0.5 mu m. The scattering-to-extinction ratio was estimated to be Tau [Subscript scat] /A[Subscript V] ~> 0.022; this is a lower limit to the true value because contribution from smaller grains, which scatter to larger angles, was not directly observed. The line of sight to the GRB passes close to the Ophiuchus molecular cloud complex, which provides a plausible site for the scattering dust.|
|Rights:||Creative Commons “Attribution Non-Commercial No Derivatives” licence CC BY-NC-ND, further details of which can be found via the following link: http://creativecommons.org/licenses/by-nc-nd/4.0/ Archived with reference to SHERPA/RoMEO and publisher website.|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
Files in This Item:
|Vaughan_2006_ApJ_639_323.pdf||Publisher version||348.75 kB||Adobe PDF||View/Open|
Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.