2005/01/10 by M. Lombardi, P. Rosati, J. P. Blakeslee +19
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/428427
published as Astrophys.J. 623 (2005) 42-56 · 38 pages, ApJ in press. Full resolution images available at http://www.eso.org/~prosati/RDCS1252/Lombardi_etal_accepted.pdf
arxiv created 2005/01/10 · openalex publication_date 2005/04/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present a weak-lensing analysis of one of the most distant massive galaxy clusters known, RDCS 1252.9-2927, at z = 1.24, using deep images from the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope ( HST ). By taking advantage of the depth and angular resolution of the ACS images, we detect for the first time at z > 1 a clear weak-lensing signal in both the i (F775W) and z (F850LP) filters. We measure a 5 σ signal in the i band and a 3 σ signal in the shallower z -band image. The two radial mass profiles are found to be in very good agreement with each other, and they provide a measurement of the total mass of the cluster inside a 1 Mpc radius of M (< 1 Mpc) = (8.0 ± 1.3) × 10 14 M ☉ in the current cosmological concordance model, h = 0.70, Ω m = 0.3, and Ω Λ = 0.7, assuming a redshift distribution of background galaxies as inferred from the Hubble Deep Field surveys. A weak-lensing signal is detected out to the boundary of our field (3' radius, corresponding to 1.5 Mpc at the cluster redshift). We detect a small offset between the centroid of the weak-lensing mass map and the brightest cluster galaxy, and we discuss the possible origin of this discrepancy. The cumulative weak-lensing radial mass profile is found to be in good agreement with the X-ray mass estimate based on Chandra and XMM-Newton observations, at least out to R 500 ≃ 0.5 Mpc.