The Multi-Band Magnification Bias for Gravitational Lenses

Abstract

We present a generalization of the concept of magnification bias for gravitationally-lensed quasars, in which the quasars are selected by flux in more than one wavelength band. To illustrate the principle, we consider the case of two-band selection, in which the fluxes in the two bands are uncorrelated, perfectly correlated, or correlated with scatter. For uncorrelated fluxes, we show that the previously-held result - that the bias is the product of the single-band biases - is generally false. We demonstrate some important properties of the multi-band magnification bias using model luminosity functions inspired by observed correlations among X-ray, optical, infrared and radio fluxes of quasars. In particular, the bias need not be an increasing function of each flux, and the bias can be extremely large for non-linear correlations. The latter fact may account for the high lensing rates found in some X-ray/optical and infrared/radio selected samples.

arXiv comment20 pages, 4 figures. Submitted to ApJ

References in corpus (25)

• The Sloan Digital Sky Survey: Technical Summary
• A Survey of z>5.8 Quasars in the Sloan Digital Sky Survey I: Discovery of Three New Quasars and the Spatial Density of Luminous Quasars at z~6
• The 2dF QSO Redshift Survey - I. The Optical QSO Luminosity Function
• Is There A Cosmological Constant?
• The Sloan Digital Sky Survey Quasar Catalog I. Early Data Release
• CDM and Strong Lensing: Concord or Conflict?
• Gravitational Lens Statistics for Generalized NFW Profiles: Parameter Degeneracy and Implications for Self-Interacting Cold Dark Matter
• The Reddest Quasars
• Global Probes of the Impact of Baryons on Dark Matter Halos
• Semi-Analytical Models for Lensing by Dark Halos: I. Splitting Angles
• Constraints on the Inner Mass Profiles of Lensing Galaxies from Missing Odd Images
• Quasars in the 2MASS Second Incremental Data Release
• Lensing Constraints on the Cores of Massive Dark Matter Halos
• Why is the Fraction of Four-Image Radio Lens Systems So High?
• Strong Gravitational Lensing and Dark Energy
• Gravitational Lensing of the SDSS High-Redshift Quasars
• Lensing and the Centers of Distant Early-Type Galaxies
• The Reddest Quasars II. A gravitationally-lensed FeLoBAL quasar
• Gravitational lensing statistics with extragalactic surveys. II. Analysis of the Jodrell Bank-VLA Astrometric Survey
• Constraining the Redshift z=6 Quasar Luminosity Function Using Gravitational Lensing
• Lensing Properties of Cored Galaxy Models
• Analytic expressions for mean magnification by a quadrupole gravitational lens
• Cosmological Microlensing Statistics: Variability rates for Quasars and GRB Afterglows, and implications for macrolensing magnification bias and flux ratios
• Discovery of a z=4.93, X-ray selected quasar by the Chandra Multiwavelength Project (ChamP)
• Constraints on the Baryonic Compression and Implications for the Fraction of Dark Halo Lenses

Cited by in corpus (12)

• Cosmology with cosmic shear observations: a review
• A quadruply imaged quasar with an optical Einstein ring candidate: 1RXS J113155.4-123155
• Strong MgII systems in quasar and gamma-ray burst spectra
• SDSS J131339.98+515128.3: A new gravitationally lensed quasar selected based on near-infrared excess
• Gravitational Lenses as High-Resolution Telescopes
• Effects of galaxy-halo alignment and adiabatic contraction on gravitational lens statistics
• A gravitational lensing explanation for the excess of strong Mg-II absorbers in GRB afterglow spectra
• Microlensing of gamma ray bursts by stars and MACHOs
• Testing the gravitational lensing explanation for the MgII problem in GRBs
• On the significance of the excess number of strong MgII absorbers observed towards Gamma-ray bursts
• Galaxies as High-Resolution Telescopes
• Fitting formulae of the reduced-shear power spectrum for weak lensing