THREE-DIMENSIONAL MULTI-PROBE ANALYSIS OF THE GALAXY CLUSTER A1689
ApJ_806_207.pdf 5.52 MB
Diego, Jose M.
cosmology: observations – dark matter – galaxies: clusters: individual (A1689) – gravitational lensing: strong – gravitational lensing: weak
Astronomy. Space sciences
We perform a three-dimensional multi-probe analysis of the rich galaxy cluster A1689, one of the most powerful known lenses on the sky, by combining improved weak-lensing data from new wide-field BVRCi'z' Subaru/ Suprime-Cam observations with strong-lensing, X-ray, and Sunyaev–Zel’dovich effect (SZE) data sets. We reconstruct the projected matter distribution from a joint weak-lensing analysis of two-dimensional shear and azimuthally integrated magnification constraints, the combination of which allows us to break the mass-sheet degeneracy. The resulting mass distribution reveals elongation with an axis ratio of ∼0.7 in projection, aligned well with the distributions of cluster galaxies and intracluster gas. When assuming a spherical halo, our full weaklensing analysis yields a projected halo concentration of c^2D_200c = 8.9 ± 1.1 (c^2D_vir ~ 11), consistent with and improved from earlier weak-lensing work. We find excellent consistency between independent weak and strong lensing in the region of overlap. In a parametric triaxial framework, we constrain the intrinsic structure and geometry of the matter and gas distributions, by combining weak/strong lensing and X-ray/SZE data with minimal geometric assumptions. We show that the data favor a triaxial geometry with minor–major axis ratio 0.39±0.15 and major axis closely aligned with the line of sight (22°±10°). We obtain a halo mass M_200c = (1.2 ± 0.2) × 10^15 Mʘ h^-1 and a halo concentration c_200c = 8.4 ± 1.3, which overlaps with the ≳1σ tail of the predicted distribution. The shape of the gas is rounder than the underlying matter but quite elongated with minor–major axis ratio 0.60 ± 0.14. The gas mass fraction within 0.9Mpc is 10 ^+3_-2 %, a typical value for high-mass clusters. The thermal gas pressure contributes to ∼60% of the equilibrium pressure, indicating a significant level of non-thermal pressure support. When compared to Planckʼs hydrostatic mass estimate, our lensing measurements yield a spherical mass ratio of M_Planck / M_GL = 0.70 ± 0.15 and 0.58 ± 0.10 with and without corrections for lensing projection effects, respectively.
The work is partially supported by the Ministry of Science and Technology of Taiwan under
the grant MOST 103-2112-M-001-030-MY3. M. S. acknowledges financial contributions from contracts ASI/INAF I/023/ 12/0, by the PRIN MIUR 2010–2011 “The dark universe and the cosmic evolution of baryons: from current surveys to Euclid” and by the PRIN INAF 2012 “The universe in the box: multiscale simulations of cosmic structure.” M. N. acknowledges financial support from PRIN INAF 2014. J. M. D. acknowledges support of the consolider project CSD2010-00064 and AYA2012-39475-C02-01 funded by the Ministerio de Economia y Competitividad. N. O. is supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (26800097). This work was partially supported by “World Premier International Research Center Initiative (WPI Initiative)” and the Funds for
the Development of Human Resources in Science and Technology under MEXT, Japan. This research was performed while T. M. held a National Research Council Research Associateship Award at the Naval Research Laboratory (NRL). We thank John Carlstrom, Megan Gralla, Marshall Joy, Dan Marrone, and the entire SZA and OVRO/BIMA teams for providing the SZA and OVRO/BIMA data used in this study. Support for the SZA observations presented in this work was provided by NSF through award AST-0838187 and PHY-0114422 at the University of Chicago. The OVRO and BIMA observations presented here were supported by National Science Foundation grants AST 99-81546 and 02-28963.
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