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Date and Time of the Query: 2019-05-23 T05:47:17 PDT
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For refcode 1988AJ.....96.1775O:
Retrieve 311 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
1988AJ.....96.1775O THE KINEMATICS AND DYNAMICS OF THE RICH CLUSTER OF GALAXIES ABELL 539 EVE C. OSTRIKER, JOHN P. HUCHRA, MARGARET J. GELLER, AND MICHAEL J. KURTZ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 Received 20 June 1988;revised 24 August 1988 ABSTRACT We use a sample of 289 redshifts (229 are new measurements) within 10^deg^ of the cluster center to study the kinematics and dynamics of the rich cluster A539. We also report new photometry for 95 galaxies in a 1.5 sq. deg region centered on the cluster. Within 1 Mpc of the center the physical parameters of A539 are typical of rich clusters: {sigma}_r_=799^+83^_-65_ km s^-1^ and M/L_R_ = 476^+140^_-122_ M_sun_/L_Rsun_. This mass-to-light ratio implies {OMEGA}_0_ ~0.2. Early-type galaxies are more concentrated toward the cluster center and the velocity distributions of early- and late-type galaxies differ marginally. For spirals, {sigma}_r_ = 649^+103^_-70_ km s^-1^ and for E+S0's, {sigma}_r_ =819^+111^_-79_ km s^-1^ within 1.5 Mpc of the center. The survey covers a sufficiently large angular scale to study the infall pattern associated with the cluster. Under the assumption that galaxies trace the matter distribution the pattern of radial velocities sets a minimum turnaround radius of ~2^deg^, which in turn, implies {OMEGA}_0_ >~0.03. For the value {OMEGA}_0_>=0.2 implied by the central M/L, the turnaround radius is in the range ~3.4^deg^- 4.4^deg^, still consistent with the pattern in velocity space. Although the data at large radii are sparse, {OMEGA}_0_=1 is probably inconsistent with the velocity-dispersion profile unless dark matter is more uniformly distributed than the galaxies. We assume that H_0_=100 km s^-1^ Mpc^-1^ throughout.
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