An X-ray transient was detected in outburst on 18 October 2005 during one of our Chandra/HRC-I observations as part of the XMM-Newton/Chandra monitoring campaign of the 1.7 square degree around Sgr A* (Wijnands et al. 2005, A&A submitted, astro-ph/0508648). The source was located ~15 arcminutes away from the aim-point which did not allow a sub

Between 1999 February and 2000 April, the QUEST1 variability survey collected 69 drift scans of the same region of high Galactic latitude sky. The scans cover a strip of equatorial sky approximately 24 wide in declination, centered at DE=-1°, running from RA=10h to 15h30m. All scans were taken with the 1m Schmidt telescope at the Llano del Hato

Despite more than 20 years of study, we still possess only limited constraints on the fundamental properties of SS433. With the exception of the 13d period, orbital parameters are ill-constrained, and hence the nature of both compact object, a neutron star or black hole, or the mass donor are still unknown. However, newly acquired high resolution

We present VLT observations of the optical counterpart of th X-ray millisecond pulsar XTE J0929-314 in quiescence. We detected a very faint candidate in agreement with the position given by radio and X observation. From the observed optical flux we inferred un upper limit to the magnetic field of the system.

We present spectra of 36 nearby star candidates and 3 red giant candidates, identified in the DENIS database. 32 of the dwarf candidates are nearby red dwarfs, with spectral types from M 5.5 to M 8.5. Out of 11 targets with low proper motion (μ 0.1 arcsec yr^-1) but a Reduced Proper Motion above an inclusive threshold, 9 are red dwarfs. The 4

We explore the possibility that the steepening observed shortward of 1000 Å in the energy distribution of quasars may result from absorption by dust, being either intrinsic to the quasar environment or intergalactic. We find that a dust extinction curve consisting of nanodiamonds, composed of terrestrial cubic diamonds or with surface impurities as