Journal Article

Magnification effects on source counts and fluxes

Bhuvnesh Jain and Marcos Lima

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 411, issue 4, pages 2113-2117
Published in print March 2011 | ISSN: 0035-8711
Published online March 2011 | e-ISSN: 1365-2966 | DOI:
Magnification effects on source counts and fluxes

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We consider the effect of lensing magnification on high-redshift sources in the case that magnification varies on the sky, as expected in wide fields of view or within observed galaxy clusters. We give expressions for number counts, flux and flux variance as integrals over the probability distribution of the magnification. We obtain these through a simple mapping between averages over the observed sky and over the magnification probability distribution in the source plane. Our results clarify conflicting expressions in the literature and can be used to calculate a variety of magnification effects. We highlight two applications: (i) lensing of high-z galaxies by galaxy clusters can provide the dominant source of scatter in Sunyaev–Zel'dovich (SZ) observations at frequencies larger than the SZ null; and (ii) the number counts of high-z galaxies with a Schechter-like luminosity function will be changed at high luminosities to a power law, with significant enhancement of the observed counts at L≳ 10L*.

Keywords: gravitational lensing: strong; galaxies: clusters: general; galaxies: general

Journal Article.  3002 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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