A fast method for computing strong-lensing cross sections

• Verfasst von: Fedeli, Cosimo [VerfasserIn]
• Verfasst von: Meneghetti, Massimo [VerfasserIn]
• Verfasst von: Bartelmann, Matthias [VerfasserIn]
• Titel: A fast method for computing strong-lensing cross sections
• Titelzusatz: application to merging clusters
• Verf.angabe: Cosimo Fedeli, Massimo Meneghetti, Matthias Bartelmann, Klaus Dolag and Lauro Moscardini
• E-Jahr: 2017
• Jahr: August 22, 2017
• Umfang: 10 S.
• Fussnoten: Gesehen am 26.09.2017
• Titel Quelle: Enthalten in: De.arxiv.org
• Ort Quelle: [S.l.] : Arxiv.org, 1991
• Jahr Quelle: 2017
• Band/Heft Quelle: (2017) Artikel-Nummer 1011.1559, 10 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Astrophysics
• K10plus-PPN: 1563803194

Abstract

Strong gravitational lensing by irregular mass distributions, such as galaxy clusters, is generally not well quantified by cross sections of analytic mass models. Computationally expensive ray-tracing methods have so far been necessary for accurate cross-section calculations. We describe a fast, semi-analytic method here which is based on surface integrals over high-magnification regions in the lens plane and demonstrate that it yields reliable cross sections even for complex, asymmetric mass distributions. The method is faster than ray-tracing simulations by factors of $\sim30$ and thus suitable for large cosmological simulations, saving large amounts of computing time. We apply this method to a sample of galaxy cluster-sized dark matter haloes with simulated merger trees and show that cluster mergers approximately double the strong-lensing optical depth for lens redshifts $z_\mathrm{l}\gtrsim0.5$ and sources near $z_\mathrm{s} = 2$. We believe that this result hints at one possibility for understanding the recently detected high arcs abundance in clusters at moderate and high redshifts, and is thus worth further studies.