Gravitational Microlensing of Gamma-Ray Burst Afterglows by Single and Binary Stars
Author(s) -
Shude Mao,
Abraham Loeb
Publication year - 2001
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/318912
Subject(s) - gravitational microlensing , physics , light curve , gamma ray burst , astrophysics , afterglow , stars , brightness , astronomy , einstein ring , binary star , line of sight , magnification , gravitational lens , sky , optics , galaxy , redshift
We calculate the magnification light curves due to stellar microlensing ofgamma-ray burst (GRB) afterglows. A GRB source appears on the sky as a thinring which expands faster than the speed of light and is maximally magnified asit crosses the lens caustics. While a single star lens produces a single peakin the magnification light curve, binary star lenses may produce multiplepeaks. The shape of the magnification light curve provides invaluableinformation on the surface brightness distribution of the afterglow photosphereon sub micro-arcsecond scales. We find that all afterglows are likely to showvariability at the level of a few percent about a year following the explosion,due to stars which are separated by tens of Einstein radii from theirline-of-sight.Comment: slightly modified version, 14 pages, 4 figures, ApJL, in pres
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