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Date and Time of the Query: 2019-03-18 T15:24:41 PDT
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For refcode 2000AJ....119...44K:
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2000AJ....119...44K KINEMATICS AND MASS PROFILE OF AWM 71 DANIEL M. KORANYI AND MARGARET J. GELLER Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; dkoranyi@cfa.harvard.edu, mgeller@cfa.harvard.edu Received 1999 June 24; accepted 1999 September 30 ABSTRACT We have measured 492 redshifts (311 new) in the direction of the poor cluster AWM 7 and have identified 179 cluster members (73 new). We use two independent methods to derive a self-consistent mass profile, under the assumptions that the absorption-line galaxies are virialized and that they trace an underlying Navarro, Frenk, & White (NFW) dark matter profile: (1) we fit such an NFW profile to the radial distribution of galaxy positions and to the velocity dispersion profile; (2) we apply the virial mass estimator to the cluster. With these assumptions, the two independent mass estimates agree to ~15% within 1.7 h^-1^ Mpc, the radial extent of our data; we find an enclosed mass ~(3 +/- 0.5) x 10^14^ h^-1^ M_sun_. The largest potential source of systematic error is the inclusion of young emission-line galaxies in the mass estimate. We investigate the behavior of the surface term correction to the virial mass estimator under several assumptions about the velocity anisotropy profile, still within the context of the NFW model, and remark on the sensitivity of derived mass profiles to outliers. We find that one must have data out to a large radius in order to determine the mass robustly, and that the surface term correction is unreliable at small radii. Key words: galaxies: clusters: individual (AWM 7)-galaxies: kinematics and dynamics
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