1994/02/08 by G. G. Fahlman, Nick Kaiser, G. Squires +2 · 6 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Dark matter #Distortion (music) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Mass distribution #Omega #Physics #RADIUS #Scientific Research and Discoveries #Star formation #Stellar mass #Virial mass #Virial theorem #astro-ph #hep-ph
paper · pdf · doi:10.1086/174974
published as Astrophys.J. 437 (1994) 56-62 · 8 pages (no figures), latex, CITA/94/4, postscript file with figures available by anonymous ftp in /cita/nick/ms1224/ at ftp.cita.utoronto.ca
arxiv created 1994/02/08 · openalex publication_date 1994/12/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We explore the dark matter distribution in MS 1224.7+2007 using the gravitational distortion of the images of faint background galaxies. Projected mass image reconstruction reveals a highly significant concentration coincident with the X-ray and optical location. The concentration is seen repeatably in reconstructions from independent subsamples, and the azimuthally averaged tangential shear pattern is also clearly seen in the data. The projected mass within a 2.76' radius aperture is ~3.5 x 1014^ h-1^ Msun_. This is ~3 times larger than that predicted if mass traces light with M/L = 275 as derived from virial analysis. It is very hard to attribute the discrepancy to a statistical fluctuation, and a further indication of a significant difference between the mass and the light comes from a second mass concentration, which is again seen in independent subsamples but which is not seen at all in the cluster light. We find a mass per galaxy visible to I = 22 of ~8 x 1012^ h-1^ Msun_, which, if representative of the universe, implies a density parameter OMEGA~2. We find a null detection of any net shear from large-scale structure with a precision of 0.9% per component. This is much smaller than the possible detection in a recent comparable study, and the precision here is at about the level of the rms shear fluctuations in realistic models.