We report on a Swift follow-up observation of the X-ray transient MAXI J1659-152 (ATel #2873, ATel #2877, GCN #11296). This source is suggested to be a stellar-mass black hole candidate (Kalamkar et al. 2011, arXiv:1012.4330). The source also has a very short orbital period ~2.4 hours (Kuulkers et al. 2011, arXiv:1102.2102). The optical counterpart

Following the gamma-ray, VHE (E>100 GeV) flare of the blazar 1ES 0806+525 (RA:08h09m49.2s DEC:+52d18m58.2s, z=0.138) detected by MAGIC on 2011 February 25 (ATel #3192), we performed a Swift target of opportunity observation starting on February 26. Swift monitored the source in photon counting mode with 5 daily observations for a total exposure of

Context. Low-ionisation, nuclear emission-line region (LINER) nuclei are said to be different from other active galactic nuclei (AGN) due to the presence of complex absorbing structures along the line-of-sight and/or an inefficient mode of accretion onto the supermassive black hole. However, this is still open. Aims: We investigate the broad band X

We present the first results of a narrow-band photometric study of the massive galaxy cluster XMMU J2235.3-2557 at z= 1.39. We obtained deep H narrow-band imaging with the Near InfraRed Imager and Spectrometer on Gemini North, corresponding to Hα emission at the cluster's redshift. Our sample consists of 82 galaxies within a radius of ˜500 kpc, 10

We chose all galaxies with radial velocity Vradio 1.0' at Galactic latitude |b|>30 ° using HyperLEDA (Paturel et al. 2003, Cat. VII/237, VII/238). (1 data file).

The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low