The Central Component of Gravitational Lens Q0957+561

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The Central Component of Gravitational Lens Q0957+561

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dc.contributor.author Shapiro, Irwin
dc.contributor.author Haarsma, Deborah B.
dc.contributor.author Winn, Joshua N.
dc.contributor.author Lehar, Joseph
dc.date.accessioned 2009-02-25T20:48:06Z
dc.date.issued 2008
dc.identifier.citation Haarsma, Deborah B., Joshua N. Winn, Irwin Shapiro, and Joseph Lehár. 2008. The Central Component of Gravitational Lens Q0957+561. The Astronomical Journal 135(3): 984-990. en
dc.identifier.issn 1538-3881 en
dc.identifier.issn 0004-6256 en
dc.identifier.uri http://nrs.harvard.edu/urn-3:HUL.InstRepos:2634168
dc.description.abstract In 1981, a faint radio source (G′) was detected near the center of the lensing galaxy of the famous “twin quasar” Q0957+561. It is still unknown whether this central radio source is a third quasar image or an active nucleus of the lensing galaxy, or a combination of both. In an attempt to resolve this ambiguity, we observed Q0957+561 at radio wavelengths of 13 cm, 18 cm, and 21 cm, using the Very Long Baseline Array in combination with the phased Very Large Array and the Green Bank Telescope. We measured the spectrum of G′ for the first time and found it to be significantly different from the spectra of the two bright quasar images. This finding suggests that the central component is primarily or entirely emission from the foreground lens galaxy, but the spectrum is also consistent with the hypothesis of a central quasar image suffering free-free absorption. In addition, we confirm the previously-reported VLBI position of G′ just north of the optical center of the lens galaxy. The position slightly favors the hypothesis that G′ originates in the lens, but is not conclusive. We discuss the prospects for further clarification of this issue. en
dc.description.sponsorship Astronomy en
dc.language.iso en_US en
dc.publisher American Institute of Physics (IOP Publishing) en
dc.relation.isversionof http://dx.doi.org/10.1088/0004-6256/135/3/984 en
dash.license LAA
dc.subject quasars: individual(Q0957+561) en
dc.subject gravitational lensing en
dc.subject instrumentation: interferometers en
dc.title The Central Component of Gravitational Lens Q0957+561 en
dc.relation.journal The Astronomical Journal en
dash.depositing.author Shapiro, Irwin

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  • FAS Scholarly Articles [6948]
    Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University

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