Detection of Cosmic Magnification with the Sloan Digital Sky Survey

By R. Scranton, B. Ménard, Gordon Richards, Robert Nichol, Adam D. Myers, B. Jain, A. Gray, M. Bartelmann, Robert J. Brunner, Andrew J. Connolly and 8 more. 2005

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We present an 8 σ detection of cosmic magnification measured by the variation of quasar density due to gravitational lensing by foreground large-scale structure. To make this measurement we used 3800 deg2 of photometric observations from the Sloan Digital Sky Survey (SDSS) containing ~200,000 quasars and 13 million galaxies. Our measurement of the galaxy-quasar cross-correlation function exhibits the amplitude, angular dependence, and change in sign as a function of the slope of the observed quasar number counts that is expected from magnification bias due to weak gravitational lensing. We show that observational uncertainties (stellar contamination, Galactic dust extinction, seeing variations, and errors in the photometric redshifts) are well controlled and do not significantly affect the lensing signal. By weighting the quasars with the number count slope, we combine the cross-correlation of quasars for our full magnitude range and detect the lensing signal at >4 σ in all five SDSS filters. Our measurements of cosmic magnification probe scales ranging from 60 h-1 kpc to 10 h-1 Mpc and are in good agreement with theoretical predictions based on the WMAP concordance cosmology. As with galaxy-galaxy lensing, future measurements of cosmic magnification will provide useful constraints on the galaxy-mass power spectrum.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/2112c1a53e257a3e451bc15cb6ea0ff4c4a3a74e

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Citations in the corpus

Gravitational lensing (2010, result): “Clear and unambiguous evidence for cosmic magnification was finally detected by the authors of [431] who measured the cross-correlation between a colour-selected sample of 200 000 distant QSOs and foreground galaxies in 3800 square degrees of the SDSS data and found a signal significant at the 8-σ l”
Galaxy Masses: A Review (2013, methodology): “The analysis of SDSS data by Mandelbaum et al. (2006a) did not detect an azimuthal variation in the lensing signal when considering the full sample of lens galaxies.”
THINK OUTSIDE THE COLOR BOX: PROBABILISTIC TARGET SELECTION AND THE SDSS-XDQSO QUASAR TARGETING CATALOG (2010, methodology): “It assumes that the flux uncertainties are known, as is the case for point-spread function (PSF) fluxes for point sources in SDSS (Ivezić et al. 2003, 2007; Scranton et al. 2005b).”
Clustering Analyses of 300,000 Photometrically Classified Quasars. I. Luminosity and Redshift Evolution in Quasar Bias (2006, methodology): “…al. 2004; Myers et al. 2006), meaning that large quasar samples can be used to mea- sure angular quasar clustering as a function of physical properties (Myers et al. 2006), and to use angular quasar clustering to probe Dark Matter (Scranton et al. 2005) and Dark Energy (Giannantonio et al. 2006).”
New Hubble Space Telescope Discoveries of Type Ia Supernovae at z ≥ 1: Narrowing Constraints on the Early Behavior of Dark Energy (2006, methodology): “Measurements of the integrated Sachs-Wolfe effect (e.g., Afshordi et al. 2004; Boughn & Crittenden 2004; Fosalba et al. 2003; Nolta et al. 2004; Scranton et al. 2005)more directly suggest the presence of dark energywith a negative pressure.”
Calibrating Redshift Distributions beyond Spectroscopic Limits with Cross-Correlations (2008, background): “These correlations can be predicted directly from the observed galaxy number counts (Scranton et al. 2005).”
EMU: Evolutionary Map of the Universe (2011, methodology): “The effect was first unambiguously detected by Scranton et al. (2005) using SDSS foreground galaxies and quasars.”
The Influence of Baryons on the Clustering of Matter and Weak-Lensing Surveys (2005, background): “…reduction of systematic errors in cosmic shear (Jarvis & Jain 2004; Jain et al. 2005; Heymans et al. 2006; references therein) and cosmic magnification measurements (Me´nard & Bartelmann 2002; Scranton et al. 2005; Zhang & Pen 2005, 2006), weak-lensing measurement is entering the precision era.”
Cosmological baryonic and matter densities from 600 000 SDSS luminous red galaxies with photometric redshifts (2006, background): “There are various effects which may cause the true angular selection function for the survey data to deviate from this binary coverage map (Scranton et al. 2005).”
Galaxy Zoo: Disentangling the Environmental Dependence of Morphology and Colour ⋆ (2008, methodology): “1 http://lahmu.phyast.pitt.edu/∼scranton/SDSSPix c© 0000 RAS, MNRAS 000, 1–19 This same scheme has been used for other clustering analyses (Scranton et al. 2005, Hansen et al. 2007) and for lensing analyses (Sheldon et al. 2007).”
Measuring the galaxy–mass and galaxy–dust correlations through magnification and reddening (2009, methodology): “We have therefore expanded the angular range used in the detection of magnification by Scranton et al. (2005) to both smaller and larger separations.”
A halo model of galaxy colours and clustering in the Sloan Digital Sky Survey (2008, methodology): “This same scheme has been used for other clustering analyses (Scranton et al. 2005, Hansen et al. 2007) and for lensing analyses (Sheldon et al. 2007).”
Clustering of High-Redshift (z ≥ 2.9) Quasars from the Sloan Digital Sky Survey (2007, background): “…due to the deliberate placing of the overlaps in regions ofhigh target density; galaxies dominate the SDSS spectroscopic targets, and beyond a subtle effect due to gravitational lensing (Scranton et al. 2005), we expect no correlation between the background quasars and the foreground galaxies.”