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dc.contributor.authorPerna, Rosalba
dc.contributor.authorLoeb, Abraham
dc.date.accessioned2019-09-24T12:03:35Z
dc.date.issued1997
dc.identifier.citationPerna, Rosalba, and Abraham Loeb. 1997. “Microlensing of Quasars by Stars in Their Damped Lyα Absorbers.” The Astrophysical Journal 489 (2): 489–500. https://doi.org/10.1086/304806.
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41393161*
dc.description.abstractThe damped Ly alpha absorbers (DLAs) in quasar spectra are believed to be the progenitors of present-day disk galaxies. We examine the probability for microlensing of background quasars by stars in their DLAs. Microlensing by an individual star should magnify the continuum but not the broad emission lines of the quasars. Consequently, the equivalent width distribution of microlensed quasars would be distorted. We model a representative spiral galaxy as a closed system composed of a bulge, a disk, and a halo, and we evolve the mass fraction of stars in the disk based on the observed metallicity of DLAs at high redshifts. The microlensing signatures are stronger if the halo of the galaxy is made of massive compact halo objects (MACHOs). In this case, the distortion imprinted by microlensing on the equivalent width distribution of quasar emission lines can be detected with high significance in a sample of similar to 10 DLAs with H I column densities N greater than or similar to 10(21) cm(-2) and absorption redshifts z(abs) less than or similar to 1. About one-tenth of all quasars with DLAs (N greater than or similar to 10(20) cm(-2)) might show excess variability on timescales shorter than 5 yr. A search for these signals would complement microlensing searches in local galaxies and calibrate the MACHO mass fraction in galactic halos at high redshifts.
dc.language.isoen_US
dc.publisherAmerican Astronomical Society
dash.licenseLAA
dc.titleMicrolensing of Quasars by Stars in Their Damped Lyα Absorbers
dc.typeJournal Article
dc.description.versionVersion of Record
dc.relation.journalThe Astrophysical Journal
dash.depositing.authorLoeb, Abraham::9975df1f269ab49c1ad5a328a1ec1476::600
dc.date.available2019-09-24T12:03:35Z
dash.workflow.comments1Science Serial ID 95224
dc.identifier.doi10.1086/304806
dash.source.volume489;2
dash.source.page489-500


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