Phase-resolved VLT spectroscopy of the bursting low-mass X-ray binaries 4U 1636-536/V801 Ara and 4U 1735-444/V926 Sco is presented. Doppler images of the NIII λ4640 Bowen transition reveal compact spots which we attribute to fluorescent emission from the donor star and enable us to define a new set of spectroscopic ephemerides. We measure Kem = 277

Aims.We have performed optical polarimetric observations of the SN 2006aj associated to the X-ray flash (XRF) of February 18, 2006, XRF 060218 that provide information on its expansion geometry. Methods: .The data were acquired in the R-band with the 0.7 m telescope of Crimea, 2.5 m Nordic Optical Telescope and the 2.2 m of Calar Alto. Results: .We

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One of the intents of the ground-based gamma-ray astronomy is to obtain a sky survey in the TeV energy region, and nowadays this target can be reached with giant arrays of telescopes, which however need many pointings due to their small field of view. A different approach is on the basis of GAW, acronym for Gamma Air Watch, an array of three

We report on 3 Chandra ACIS-I observations containing the two M31 transient X-ray sources announced by Haberl et al. (2006, ATel #881) and followed up by Pietsch et al. (2006, ATel #899). These observations are part of our ongoing Chandra/HST M31 transient program XMMU J004215.8+411924: This High Mass X-ray Binary was first observed with Chandra

Context: .Free-floating planetary-mass objects have masses below the deuterium burning mass limit at about 13 Jupiter masses, and have mostly been found in very young open clusters. Their origin and relationship to stars and brown dwarfs are still a mystery. Aims: .The recent detection by direct imaging of three giant planets at wide separation (50