Weak lensing calibrated M-T scaling relation of galaxy groups in the COSMOS field

Kettula, K.; Finoguenov, A.; Massey, R.; Rhodes, J.; Hoekstra, H.; Taylor, J.E.; Spinelli, P.F.; Tanaka, M.; Ilbert, O.; Capak, P.; McCracken, H.J.; Koekemoer, A.

doi:10.1088/0004-637x/778/1/74

Weak lensing calibrated M-T scaling relation of galaxy groups in the COSMOS field

Kettula, K.; Finoguenov, A.; Massey, R.; Rhodes, J.; Hoekstra, H.; Taylor, J.E.; Spinelli, P.F.; Tanaka, M.; Ilbert, O.; Capak, P.; McCracken, H.J.; Koekemoer, A.

Authors

K. Kettula

A. Finoguenov

Professor Richard Massey r.j.massey@durham.ac.uk
Professor

J. Rhodes

H. Hoekstra

J.E. Taylor

P.F. Spinelli

M. Tanaka

O. Ilbert

P. Capak

H.J. McCracken

A. Koekemoer

Abstract

The scaling between X-ray observables and mass for galaxy clusters and groups is instrumental for cluster-based cosmology and an important probe for the thermodynamics of the intracluster gas. We calibrate a scaling relation between the weak lensing mass and X-ray spectroscopic temperature for 10 galaxy groups in the COSMOS field, combined with 55 higher-mass clusters from the literature. The COSMOS data includes Hubble Space Telescope imaging and redshift measurements of 46 source galaxies per arcminute2, enabling us to perform unique weak lensing measurements of low-mass systems. Our sample extends the mass range of the lensing calibrated M-T relation an order of magnitude lower than any previous study, resulting in a power-law slope of $1.48^{+0.13}_{-0.09}$. The slope is consistent with the self-similar model, predictions from simulations, and observations of clusters. However, X-ray observations relying on mass measurements derived under the assumption of hydrostatic equilibrium have indicated that masses at group scales are lower than expected. Both simulations and observations suggest that hydrostatic mass measurements can be biased low. Our external weak lensing masses provide the first observational support for hydrostatic mass bias at group level, showing an increasing bias with decreasing temperature and reaching a level of 30%-50% at 1 keV.

Citation

Kettula, K., Finoguenov, A., Massey, R., Rhodes, J., Hoekstra, H., Taylor, J., …Koekemoer, A. (2013). Weak lensing calibrated M-T scaling relation of galaxy groups in the COSMOS field. Astrophysical Journal, 778(1), Article 74. https://doi.org/10.1088/0004-637x/778/1/74

Journal Article Type	Article
Publication Date	Nov 1, 2013
Deposit Date	Jun 30, 2014
Publicly Available Date	Aug 19, 2014
Journal	Astrophysical Journal
Print ISSN	0004-637X
Electronic ISSN	1538-4357
Publisher	American Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	778
Issue	1
Article Number	74
DOI	https://doi.org/10.1088/0004-637x/778/1/74
Keywords	Cosmology: observations, Galaxies: groups: general, Gravitational lensing: weak.