Observing Long Cosmic Strings Through Gravitational Lensing

Abstract

We consider the gravitational lensing produced by long cosmic strings formed in a GUT scale phase transition. We derive a formula for the deflection of photons which pass near the strings that reduces to an integral over the light cone projection of the string configuration plus constant terms which are not important for lensing. Our strings are produced by performing numerical simulations of cosmic string networks in flat, Minkowski space ignoring the effects of cosmological expansion. These strings have more small scale structure than those from an expanding universe simulation - fractal dimension 1.3 for Minkowski versus 1.1 for expanding - but share the same qualitative features. Lensing simulations show that for both point-like and extended objects, strings produce patterns unlike more traditional lenses, and, in particluar, the kinks in strings tend to generate demagnified images which reside close to the string. Thus lensing acts as a probe of the small scale structure of a string. Estimates of lensing probablity suggest that for string energy densities consistant with string seeded structure formation, on the order of tens of string lenses should be observed in the Sloan Digital Sky Survey quasar catalog. We propose a search strategy in which string lenses would be identified in the SDSS quasar survey, and the string nature of the lens can be confirmed by the observation of nearby high redshift galaxies which are also be lensed by the string.

24 pages revtex with 12 postscript firgures

References in corpus (2)

• Evolution of the Galaxy Population Based on Photometric Redshifts in the Hubble Deep Field
• Large Angular Scale CMB Anisotropy Induced by Cosmic Strings

Cited by in corpus (13)

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• Direct Observation of Cosmic Strings via their Strong Gravitational Lensing Effect: II. Results from the HST/ACS Image Archive
• Wave effect in gravitational lensing by a cosmic string
• Gravitational backreaction on a cosmic string: Formalism
• Cosmic String Loop Microlensing
• Weak lensing of CMB by cosmic (super-)strings
• Clustering of Superstring Loops
• Prospects of Cosmic Superstring Detection through Microlensing of Extragalactic Point-Like Sources
• Analytic Approaches to the Study of Small Scale Structure on Cosmic String Networks