Weak-Lensing Detection of Cl 1604+4304 atz = 0.90

We present a weak lensing analysis of the high-redshift cluster Cl 1604+4304.At z=0.90, this is the highest-redshift cluster yet detected with weak lensing.It is also one of a sample of high-redshift, optically-selected clusters whoseX-ray temperatures are lower than expected based on their velocity dispersions.Both the gas temperature and galaxy velocity dispersion are proxies for itsmass, which can be determined more directly by a lensing analysis. Modeling thecluster as a singular isothermal sphere, we find that the mass contained withinprojected radius R is 3.69+-1.47 * (R/500 kpc) 10^14 M_odot. This correspondsto an inferred velocity dispersion of 1004+-199 km/s, which agrees well withthe measured velocity dispersion of 989+98-76 km/s (Gal & Lubin 2004). Thesenumbers are higher than the 575+110-85 km/s inferred from Cl 1604+4304 X-raytemperature, however all three velocity dispersion estimates are consistentwithin ~ 1.9 sigma.Comment: Revised version accepted for publication in AJ (January 2005). 2 added figures (6 figures total