Browsing by Author "Keeton, CR"

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    SDSS J090334.92+502819.2: A new gravitational lens
    (2003) Johnston, DE; Richards, GT; Frieman, JA; Keeton, CR; Strauss, MA; Knapp, GR; Becker, RH; White, RL; Johnson, ET; Ma, ZM; SubbaRao, M; Bahcall, NA; Bernardi, M; Brinkmann, J; Eisenstein, DJ; Fukugita, M; Hall, PB; Inada, N; Pindor, B; Schlegel, DJ; Scranton, R; Sheldon, ES; Schneider, DP; Szalay, AS; York, DG
    We report the discovery of a new gravitationally lensed quasar from the Sloan Digital Sky Survey, SDSS J090334.92+502819.2. This object was targeted for SDSS spectroscopy as a luminous red galaxy, but manual examination of the spectrum showed the presence of a quasar at zsimilar or equal to3.6 in addition to a red galaxy at z=0.388, and the SDSS image showed a second possible quasar image nearby. Follow-up imaging and spectroscopy confirmed the lensing hypothesis. In images taken at the Astrophysical Research Consortium 3.5 m telescope, two quasars are separated by 2".8; the lensing galaxy is clearly seen and is blended with one of the quasar images. Spectroscopy taken at the Keck II telescope shows that the quasars have identical redshifts of zsimilar or equal to3.6, and both show the presence of the same broad absorption line-like troughs. We present simple lens models that account for the geometry and magnifications. The lens galaxy lies near two groups of galaxies and may be a part of them. The models suggest that the groups may contribute considerable shear that has a strong effect on the lens configuration.
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    The redshift of a lensing galaxy in PMN J0134-0931
    (2002) Hall, PB; Richards, GT; York, DG; Keeton, CR; Bowen, DV; Schneider, DP; Schlegel, DJ; Brinkmann, J
    The Sloan Digital Sky Survey (SDSS) automatically targeted as a quasar candidate the recently discovered, gravitationally lensed, extremely reddened z = 2.2 quasar PMN 0134-0931. The SDSS spectrum exhibits Ca II absorption at z = 0.76451, which we identify as the redshift of a lensing galaxy. Hubble Space Telescope imaging shows that components C, D, and E of the system are significantly redder than components A or B and detects faint galaxy emission between D and A+B. The redshift of the dust responsible for the reddening remains unconstrained with current data. However, we outline a model wherein lensing and differential reddening by a z = 0.76454 galaxy pair can entirely explain this system.