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(Abridged) Chandra and Hubble ACS observations of 11 early-type galaxies probe the low-mass X-ray binary (LMXB) - globular cluster (GC) connection. We explore the optical properties of 270 GCs with LMXBs and 6,488 GCs without LMXBs. More massive, redder, and more compact GCs are more likely to contain LMXBs. Unlike Galactic GCs, a large number of GCs with LMXBs have half-mass relaxation times > 2.5 Gyr. We fit the dependence of the expected number of LMXBs per GC, lambda_t, on the GC mass M, color (g-z), and half-mass radius r_{h,cor}, and find that lambda_t propto M^{1.24pm0.08} 10^{0.9^{+0.2}_{-0.1} (g-z)} r_{h,cor}^{-2.2^{+0.3}_{-0.4}}. Our fit rules out that the number of LMXBs per GC is linearly proportional to GC mass and that most GCs with high X-ray luminosities contain a single LMXB. The detailed dependence of lambda_t on GC properties appears essentially equivalent to a dependence on the encounter rate Gamma_h and the metallicity Z, lambda_t propto Gamma_h^{0.82pm0.05} Z^{0.39pm0.07}. Our analysis provides strong evidence that dynamical formation and metallicity play the primary roles in determining the presence of an LMXB in extragalactic GCs. The shallower than linear dependence for our sample requires an explanation by theories of dynamical binary formation. The abundance dependence is consistent with a metallicity-dependent variation in the number o neutron stars and black holes per unit mass GC, effects from irradiation induced winds or suppression of magnetic braking in metal-poor stars.
We present the results of a Chandra/HST study of the point sources of the NGC 4472. We identify 144 X-ray sources, 72 with HST matches. The optical data show 1102 sources, 829 with globular cluster colors. Thirty matches are found - likely to be low
We present a wide field study of the Globular Clusters/Low Mass X-ray Binaries connection in the cD elliptical NGC1399, combining HST/ACS and Chandra high resolution data. We find evidence that LMXB formation likelihood is influenced by GCs structura
We study the UV properties of a volume limited sample of early-type galaxies in the Virgo cluster combining new GALEX far- (1530 A) and near-ultraviolet (2310 A) data with spectro-photometric data available at other wavelengths. The sample includes 2
Studies of nearby elliptical and S0 galaxies reveal that roughly half of the low mass X-ray binaries (LMXBs), which are luminous tracers of accreting neutron star or black hole systems, are in clusters. There is a surprising tendency of LMXBs to be p
We present a study of globular clusters (GCs) in 17 relatively nearby early-type galaxies, based on deep HST/WFPC2 F555W and F814W images. We compare color distributions, cluster sizes and luminosity functions with those of GCs in the Milky Way. In n