We report the detection of 1WGA J1226.9+3332 as an arcminute-scale extended X-ray source with the Chandra X-Ray Observatory. The Chandra observation and R- and K-band imaging strongly support the identification of 1WGA 1226.9+3332 as a high-redshift cluster of galaxies, most probably at z = 0.85 +/- 0.15, with an inferred temperature kT = 10(-3)(+4) keV, and an unabsorbed luminosity (in a r = 120" aperture) of 1.3(-0.14)(+0.16) x 10(45) ergs s(-1) (0.5-10 keV). This indication of redshift is also supported by the K- and R-band imaging and is in agreement with the spectroscopic redshift of 0.89 found by Ebeling and coworkers. The surface brightness profile is consistent with a beta model with beta = 0.770 +/- 0.025, r(c) = 18."1+/-0."9 (corresponding to 101 +/- 5 kpc at z = 0.89), and S(0) = 1.02 +/- 0.08 counts arcsec(-2). 1WGA J1226.9+3332 was selected as an extreme X-ray-loud source with F-X/F-V >60; this selection method, thanks to the large area sampled, seems to be a highly efficient method for finding luminous, high-z clusters of galaxies.
