2001ApJ...560...86C

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⁺⁴_–3 keV, and an unabsorbed luminosity (in a r=120'' aperture) of 1.3^+0.16_–0.14x10⁴⁵ 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 β model with β=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.