Weak lensing analysis of Cl 1358+62 using Hubble Space Telescope observations

TL;DR

This paper presents a weak lensing analysis of galaxy cluster Cl 1358+62 using Hubble Space Telescope data, measuring its mass distribution and comparing it with other estimates.

Contribution

The study provides a detailed weak lensing measurement of Cl 1358+62, including shape correction methods for HST PSF anisotropy and comparison with dynamical and X-ray mass estimates.

Findings

Measured shear consistent with a velocity dispersion of 780 km/s

Mass distribution is elongated with an axis ratio of 0.30

Mass-to-light ratio estimated at 90 h50 M_sun/L_Vsun

Abstract

We report on the detection of weak gravitational lensing of faint, distant background galaxies by Cl 1358+62, a cluster of galaxies at a redshift of z=0.33. The observations were made using the HST. The measured shear is consistent with a velocity dispersion of 780+-50 km/s. The weak lensing mass is slightly lower than dynamical estimates and agrees well with X-ray mass estimates. The mass distribution is elongated similar to the light. The axis ratio of 0.30+-0.15 and position angle of -21+-8 degrees were measured directly from the observed shear and agree very well with a previous strong lensing analysis. We estimate the mass-to-light ratio to be 90+-13 h50 M_sun/L_Vsun. The HST point spread function is highly anisotropic at the edges of the individual chips. This systematically perturbs the shapes of objects and we present a method for applying the appropriate correction.