Swift XRT observed the recently discovered source XTE J1701-407 (Markwardt et al., ATel #1569, Degenaar et al., ATel #1572) on July 17th, 2008 at UT 13:31:45, 97 seconds after the Swift-BAT detection of an X-ray flare (Barthelmy et al., GCN Circ. #7985; Markwardt et al., Atel #1616), for a total exposure time of nearly two kiloseconds. We report

We describe the boxy bulge, long stellar bar and elliptical ring of the Galaxy. This model has largely evolved from NIR survey work by many teams and differs from other models with a monolithic ellipsoidal bulge. We maintain that the structure of the inner Galaxy can only be properly studied by adequately sampling the entire Galactic plane for |l|

Aims: This is the first paper of a series devoted to studying the population of blue massive stars in NGC 55, a galaxy of the Sculptor group at a distance of about 2 Mpc. Methods: We have obtained optical (3300{-}6210 Å), low-resolution spectra of approximately 200 blue massive stars with VLT-FORS2, which we have classified with the aid of Milky

All but three (M87, BL Lac, and 3C 279) extragalactic sources detected so far at very high energy γ-rays belong to the class of high-frequency-peaked BL Lac objects. This suggested to us a systematic scan of candidate sources with the MAGIC telescope, based on the Donato et al. compilation of X-ray blazars. The observations took place from 2004

We present time-resolved photometry of the optical counterpart to the black hole candidate Swift J1753.5-0127 which has remained in the low/hard X-ray state and bright at optical/IR wavelengths since its discovery in 2005. At the time of our observations Swift J1753.5-0127 does not show a decay trend but remains stable at R=16.45 with a night-to

We have conducted simultaneous optical and X-ray observations of SWIFT J1753.5-0127 with RXTE and ULTRACAM, while the system persisted in its relatively bright low/hard state. In the cross-correlation function, we find that the optical emission, with a broad negative peak, leads the X-ray emission by a few seconds and has a smaller positive peak at