Astrophys. J., 673, 163-175 (2008/January-3)
Probing the relation between X-ray-derived and weak-lensing-derived masses for shear-selected galaxy clusters. I. A781.
SEHGAL N., HUGHES J.P., WITTMAN D., MARGONINER V., TYSON J.A., GEE P. and DELL'ANTONIO I.
Abstract (from CDS):
We compare X-ray and weak-lensing masses for four galaxy clusters that comprise the top-ranked shear-selected cluster system in the Deep Lens Survey. The weak-lensing observations of this system, which is associated with A781, are from the Kitt Peak Mayall 4 m telescope, and the X-ray observations are from both Chandra and XMM-Newton. For a faithful comparison of masses, we adopt the same matter density profile for each method, which we choose to be an NFW profile. Since neither the X-ray nor the weak-lensing data are deep enough to well constrain both the NFW scale radius and central density, we estimate the scale radius using a fitting function for the concentration derived from cosmological hydrodynamic simulations and an X-ray estimate of the mass assuming isothermality. We keep this scale radius in common for both X-ray and weak-lensing profiles, and fit for the central density, which scales linearly with mass. We find that for three of these clusters, there is agreement between X-ray and weak-lensing NFW central densities, and thus masses. For the other cluster, the X-ray central density is higher than that from weak lensing by 2 σ. X-ray images suggest that this cluster may be undergoing a merger with a smaller cluster. This work serves as an additional step toward understanding the possible biases in X-ray and weak-lensing cluster mass estimation methods. Such understanding is vital to efforts to constrain cosmology using X-ray or weak-lensing cluster surveys to trace the growth of structure over cosmic time.
Cosmology: Observations - Galaxies: Clusters: General - galaxies: clusters: individual (A781) - Cosmology: Gravitational Lensing - X-Rays: Galaxies: Clusters
Fig.1, Table 1: [SHW2008] Main Cluster, [SHW2008] Middle Cluster, [SHW2008] East Cluster, [SHW2008] West Cluster, [SHW2008] Subcluster.
Status at CDS:
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