We report the serendipitous discovery of a cluster of galaxies at z = 0.369. Thirty-eight candidate members were identified based on rough broadband photometric redshifts, and three members were confirmed spectroscopically. The brightest cluster galaxy (BCG) is exceptionally blue, with B-V =0.12 and V-I = 1.02. The surface-brightness profile of the BCG follows an r(1/4) law profile out to 3 " in all three bands. The effective radius is significantly smaller in bluer bandpasses, resulting in a blue core and a color gradient opposite to the metallicity-induced color gradient observed in typical elliptical galaxies. Beyond 3 ", an extended envelope of emission in excess of the r(1/4) law profile is observed, the position angle of which coincides with the major axis of the galaxy cluster. The spectrum of the BCG contains strong Balmer absorption, a minimal 4000 Angstrom break, and a broad Mg II emission line, suggesting that the galaxy has undergone recent star formation and may harbor a central active galactic nucleus. The presence of numerous nearby bright stars makes this cluster an interesting target for next-generation adaptive optics using natural guide stars. References: 29
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