We report on the Chandra X-ray Observatory observations of the globular cluster NGC 288. We detect four X-ray sources within the core radius and seven additional sources within the half-mass radius down to a limiting luminosity of LX = 7×1030 ergs s−1 (assuming cluster membership) in the 0.3–7 keV band. We also observed the cluster with the Hubble Space Telescope Advanced Camera for Surveys and...

We report on the Chandra X-ray Observatory observations of the globular cluster NGC 288. We detect four X-ray sources within the core radius and seven additional sources within the half-mass radius down to a limiting luminosity of LX = 7×1030 ergs s−1 (assuming cluster membership) in the 0.3–7 keV band. We also observed the cluster with the Hubble Space Telescope Advanced Camera for Surveys and...

We present an X-ray analysis of a 4 Gyr old open cluster, M67, using archival XMM–Newton data. The aim of this study was to find new X-ray members of M67, and to use the updated member list for studying X-ray variability, and derive the X-ray luminosity functions (XLFs) of different stellar types and compare them with other star clusters of similar age. We report the detection of X-ray emission...

Variable non-thermal radio emission from Galactic X-ray binaries is a trace of relativistic jets, created near accretion disks. The spectral characteristics of a lot of radio flares in the X-ray binaries with jets (RJXB) is discussed in this report. We carried out several long daily monitoring programs with the RATAN-600 radio telescope of the sources: SS433, Cyg X-3, LS I +61303, GRS 1915+10 a...

We have carried out a deep X-ray and optical survey with Chandra and HST of low-extinction regions in the Galactic bulge. Here we present the results of a search for low-luminosity (LX . 1034 ergs s−1) accreting binaries among the Chandra sources in the region closest to the Galactic Center, at an angular offset of 1.4, that we have named the Limiting Window. Based on their blue optical colors,...

We present the analysis of simultaneous X-ray (RXTE) and radio (VLA) observations of two atoll-type neutron star X-ray binaries: 4U 1820–30 and Ser X-1. Both sources were steadily in the soft (banana) X-ray state during the observations. We have detected the radio counterpart of 4U 1820–30 at 4.86 GHz and 8.46 GHz at a flux density of ∼ 0.1 mJy. This radio source is positionally coincident with...

This paper surveys our current knowledge of the hard X-ray emission properties of old accreting neutron stars in low mass X-ray binaries. Hard X-ray components extending up to energies of a few hundred keV have been clearly detected in sources of both the Atoll and Z classes. The presence and characteristics of these hard components are discussed in relation to source properties and state. An o...

I partially review our current knowledge on microquasars, making special emphasis on radio interferometric observations, and I comment on emerging trends in this field of astrophysics. 1. X-ray binaries, radio emission and microquasars An X-ray binary is a binary system containing a compact object, either a neutron star or a stellar-mass black hole accreting matter from the companion star. The ...