We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Efficient mass estimate at the core of strong lensing galaxy clusters using the Einstein radius.

González, J. D. Remolina and Sharon, K. and Reed, B. and Li, N. and Mahler, G. and Bleem, L. E. and Gladders, M. and Niemiec, A. and Acebron, A. and Child, H. (2020) 'Efficient mass estimate at the core of strong lensing galaxy clusters using the Einstein radius.', Astrophysical journal., 902 (1). p. 44.


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.

Item Type:Article
Full text:(VoR) Version of Record
Download PDF
Publisher Web site:
Publisher statement:© 2020. The American Astronomical Society. All rights reserved.
Date accepted:24 August 2020
Date deposited:27 October 2020
Date of first online publication:09 October 2020
Date first made open access:27 October 2020

Save or Share this output

Look up in GoogleScholar