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dc.contributor.authorLoeb, Abraham
dc.contributor.authorPerna, Rosalba
dc.date.accessioned2019-09-24T12:04:02Z
dc.date.issued1998
dc.identifier.citationLoeb, Abraham, and Rosalba Perna. 1998. “Microlensing of Gamma‐Ray Burst Afterglows.” The Astrophysical Journal 495 (2): 597–603. https://doi.org/10.1086/305337.
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41393224*
dc.description.abstractThe afterglow of a cosmological gamma-ray burst (GRB) should appear on the sky as a narrow emission ring of radius similar to 3 x 10(16) cm (t/day)(5/8) that expands faster than light. After a day, the ring radius is comparable to the Einstein radius of a solar mass lens at a cosmological distance. Thus, microlensing by an intervening star can significantly modify the light curve and polarization signal from a GRB afterglow. We show that the achromatic amplification signal of the afterglow flux can be used to determine the impact parameter and expansion rate of the source in units of the Einstein radius of the lens, and we probe the superluminal nature of the expansion. If the synchrotron emission from the afterglow photosphere originates from a set of coherent magnetic field patches, microlensing would induce polarization variability as a result of the transient magnification of the patches behind the lens. The microlensing interpretation of the flux and polarization data can be confirmed by a parallax experiment that would probe the amplification peak at different times. The fraction of microlensed afterglows can be used to calibrate the density parameter of stellar-mass objects in the universe.
dc.language.isoen_US
dc.publisherAmerican Astronomical Society
dash.licenseLAA
dc.titleMicrolensing of Gamma‐Ray Burst Afterglows
dc.typeJournal Article
dc.description.versionVersion of Record
dc.relation.journalThe Astrophysical Journal
dash.depositing.authorLoeb, Abraham::9975df1f269ab49c1ad5a328a1ec1476::600
dc.date.available2019-09-24T12:04:02Z
dash.workflow.comments1Science Serial ID 95397
dc.identifier.doi10.1086/305337
dash.source.volume495;2
dash.source.page597-603


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