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

Journal Article · Wed Nov 20 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/778/1/74· OSTI ID:22341996

Kettula, K.; Finoguenov, A. ^[1]; Massey, R. ^[2]; Rhodes, J. ^[3]; Hoekstra, H. ^[4]; Taylor, J. E. ^[5]; Spinelli, P. F. ^[6]; Tanaka, M. ^[7]; Ilbert, O. ^[8]; Capak, P. ^[9]; McCracken, H. J. ^[10]

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1. Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland)
2. Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom)
3. California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
4. Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands)
5. Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada)
6. Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG), Rua do Matão, 1226 Cidade Universitária 05508-090, São Paulo, SP (Brazil)
7. National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)
8. LAM, CNRS-UNiv Aix-Marseille, 38 rue F. Joliot-Curis, F-13013 Marseille (France)
9. Spitzer Science Center, 314-6 Caltech, 1201 East California Boulevard Pasadena, CA 91125 (United States)
10. Institut d'Astrophysique de Paris, UMR 7095, 98 bis Boulevard Arago, F-75014 Paris (France)

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 arcminute{sup 2}, 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{sub −0.09}{sup +0.13}. 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.

• OSTI ID: 22341996
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 778; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC X-RAY SOURCES
COSMOLOGY
FORECASTING
GALAXIES
GALAXY CLUSTERS
GRAVITATIONAL LENSES
KEV RANGE
MASS
RED SHIFT
SCALING
SIMULATION
SPACE
TELESCOPES
THERMODYNAMICS
UNIVERSE
X RADIATION