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Efficient Mass Estimate at the Core of Strong Lensing Galaxy Clusters Using the Einstein Radius

González, J.D. Remolina; Sharon, K.; Reed, B.; Li, N.; Mahler, G.; Bleem, L.E.; Gladders, M.; Niemiec, A.; Acebron, A.; Child, H.

Efficient Mass Estimate at the Core of Strong Lensing Galaxy Clusters Using the Einstein Radius Thumbnail


Authors

J.D. Remolina González

K. Sharon

B. Reed

N. Li

G. Mahler

L.E. Bleem

M. Gladders

A. Acebron

H. Child



Abstract

In the era of large surveys, yielding thousands of galaxy clusters, efficient mass proxies at all scales are necessary in order to fully utilize clusters as cosmological probes. At the cores of strong lensing clusters, the Einstein radius can be turned into a mass estimate. This efficient method has been routinely used in literature, in lieu of detailed mass models; however, its scatter, assumed to be $\sim 30 \% $, has not yet been quantified. Here, we assess this method by testing it against ray-traced images of cluster-scale halos from the Outer Rim N-body cosmological simulation. We measure a scatter of 13.9% and a positive bias of 8.8% in $M(\lt {\theta }_{{\rm{E}}})$, with no systematic correlation with total cluster mass, concentration, or lens or source redshifts. We find that increased deviation from spherical symmetry increases the scatter; conversely, where the lens produces arcs that cover a large fraction of its Einstein circle, both the scatter and the bias decrease. While spectroscopic redshifts of the lensed sources are critical for accurate magnifications and time delays, we show that for the purpose of estimating the total enclosed mass, the scatter introduced by source redshift uncertainty is negligible compared to other sources of error. Finally, we derive and apply an empirical correction that eliminates the bias, and reduces the scatter to 10.1% without introducing new correlations with mass, redshifts, or concentration. Our analysis provides the first quantitative assessment of the uncertainties in $M(\lt {\theta }_{{\rm{E}}})$, and enables its effective use as a core mass estimator of strong lensing galaxy clusters.

Citation

González, J. R., Sharon, K., Reed, B., Li, N., Mahler, G., Bleem, L., …Child, H. (2020). Efficient Mass Estimate at the Core of Strong Lensing Galaxy Clusters Using the Einstein Radius. Astrophysical Journal, 902(1), Article 44. https://doi.org/10.3847/1538-4357/abb2a1

Journal Article Type Article
Acceptance Date Aug 24, 2020
Online Publication Date Oct 9, 2020
Publication Date 2020-10
Deposit Date Oct 27, 2020
Publicly Available Date Mar 29, 2024
Journal Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 902
Issue 1
Article Number 44
DOI https://doi.org/10.3847/1538-4357/abb2a1

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Copyright Statement
© 2020. The American Astronomical Society. All rights reserved.





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