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An astrophysics data program investigation of cluster evolutionA preliminary status report is given on studies using the Einstein x ray observations of distant clusters of galaxies that are also candidates for gravitational lenses. The studies will determine the location and surface brightness distribution of the x ray emission from clusters associated with selected gravitational lenses. The x ray emission comes from hot gas that traces out the total gravitational potential in the cluster, so its distribution is approximately the same as the mass distribution causing gravitational lensing. Core radii and x ray virial masses can be computed for several of the brighter Einstein sources, and preliminary results are presented on A2218. Preliminary status is also reported on a study of the optical data from 0024+16. A provisional value of 1800 to 2200 km/s for the equivalent velocity dispersion is obtained. The ultimate objective is to extract the mass of the gravitational lens, and perhaps more detailed information on the distribution of matter as warranted. A survey of the Einstein archive shows that the clusters A520, A1704, 3C295, A2397, A1722, SC5029-247, A3186 and A370 have enough x ray counts observed to warrant more detailed optical observations of arcs for comparison. Mass estimates for these clusters can therefore be obtained from three independent sources: the length scale (core radius) that characterizes the density dropoff of the x ray emitting hot gas away from its center, the velocity dispersion of the galaxies moving in the cluster potential, and gravitational bending of light by the total cluster mass. This study will allow the comparison of these three techniques and ultimately improve the knowledge of cluster masses.
Document ID
19900013194
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Kellogg, Edwin M.
(Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1990
Subject Category
Astrophysics
Report/Patent Number
NAS 1.26:181296
NASA-CR-181296
Accession Number
90N22510
Funding Number(s)
CONTRACT_GRANT: NAG5-1200
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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