Binary Quasars Observed by Chandra

We present analysis of Chandra X-ray imaging and spectroscopy for a sample of 14 quasars in close pairs, targeted as part of a complete sample of binary quasar candidates with small transverse separations drawn from Sloan Digital Sky Survey (SDSS). One pair, SDSS J1254+0846 at z=0.44 clearly inhabits an ongoing, pre-coalescence galaxy merger showing obvious tidal tails. We measure the X-ray properties of all 14 QSOs, and study the distribution of X-ray and optical-to-X-ray power-law indices in these binary quasars, and find no significant difference with large control samples of isolated quasars. We present near-IR photometry from UKIDDS, 2MASS or the MMT with SWIRC, and fit simple spectral energy distributions to all 14 QSOs, and find preliminary evidence that substantial contributions from star formation are required, but no more so than for isolated X-ray-detected QSOs. Sensitive searches of the X-ray images for extended emission, and the optical images for optical galaxy excess show that these binary QSOs, while likely occurring in strong peaks of the dark matter distribution, are not preferentially found in rich cluster environments.