Related papers: PKS 0537-441: extended [O II] emission and a binar…

We report deep optical integral-field spectroscopy with the MUSE of the luminous radio-quiet QSO PG1307+085 (z=0.154) obtained during the commissioning of the instrument. Given the high sensitivity and spatial resolution delivered by MUSE,…

We present imaging and spectro- polarimetric observations of the ultraluminous infrared galaxy IRAS P09104+4109 using the Keck 10-m Telescope. We detect the clear presence of broad Hb, Hg, and MgII 2800 emission lines in the polarized flux…

We take advantage of gravitational lensing amplification by Abell 1689 (z=0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux…

We present the main results of the first long-term spectrophotometric monitoring of the ``Einstein cross'' Q2237+0305 and of the single-epoch spectra of the lensed quasar J1131-1231. From October 2004 to December 2006, we find that two…

Narrowband observations have detected no Ly-alpha emission within a 70 pMpc^3 volume centered on the z = 2.168 quasar PKS 0424-131. This is in contrast to surveys of Ly-alpha emitters in the field at similar redshifts and flux limits, which…

We present the analysis of single epoch long slit spectra of the three brightest images of the gravitationally lensed system J1131-1231. These spectra provide one of the clearest observational evidence for differential micro-lensing of…

The BL Lac object RGB 1745+398 lies in an environment that makes it possible to study the cluster around it more deeply than the environments of other BL Lac objects. The cluster centered on the BL Lac works as a strong gravitational lens,…

The initial results of a millimeter (CO) survey of infrared-excess, optically-selected quasars from the Palomar-Green (PG) Bright Quasar Survey (BQS) with redshifts in the range 0.04 < z < 0.17 are presented. These observations represent…

We performed optical spectroscopic monitoring of the BL Lac object AO 0235+164 (z=0.94) with the VLT and TNG telescopes from Aug. 2003 to Dec. 2004, during an extended WEBT campaign. The flux of this source is both contaminated and absorbed…

We present the detection and analysis of a weak low-ionization absorber at $z = 0.12122$ along the blazar sightline PG~$1424+240$, using spectroscopic data from both $HST$/COS and STIS. The absorber is a weak Mg II analogue, with incidence…

Results of a narrow-band imaging for the redshifted [OII]3727 emission around a quasar at z=4.7 obtained with the Subaru telescope and CISCO (a Cassegrain near infrared camera) are presented. A significant emission line is detected in the…

We present the results of a Chandra observation of the galaxy cluster Abell 689 (z=0.279). Abell 689 is one of the most luminous clusters detected in the ROSAT All Sky Survey (RASS), but was flagged as possibly including significant point…

We use the high magnification event seen in the 1999 OGLE campaign light curve of image C of the quadruply imaged gravitational lens Q2237+0305 to study the structure of the quasar engine. We have obtained g'- and r'-band photometry at the…

Results of a careful analysis of the absorption systems with zabs = zem seen toward the bright, z_em ~ 3.91, gravitationally lensed quasar APM 08279+5255 are presented. Two of the narrow-line systems, at z_abs = 3.8931 and z_abs = 3.9135,…

We present the results of the first long-term (2.2 years) spectroscopic monitoring of a gravitationally lensed quasar, namely the Einstein Cross Q2237+0305. The goal of this paper is to present the observational facts to be compared in…

We report the discovery of a new gravitationally lensed QSO, at a redshift z = 1.689, with four QSO components in a cross-shaped arrangement around a bright galaxy. The maximum separation between images is 2.6 arcsec, enabling a reliable…

We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a sample of 22 BL Lac objects detected (or candidates) at TeV energies, aimed to determine or constrain their redshift. This is of…

Near-infrared images of the luminous, high redshift (z=2.1108) radio loud quasar 4C+09.17 reveal a complex structure. The quasar (K=15.76 mag) is surrounded by three "companion" objects having 17.9< K < 20.2 mag at radii of 1.7" < r < 2.9",…

We present a spectropolarimetric survey of 36 broad absorption line quasi-stellar objects (BAL QSOs). The continuum, absorption trough, and emission line polarization of BAL QSOs yield clues about their structure. We confirm that BAL QSOs…

We present a high-resolution, high signal-to-noise optical spectrum of the afterglow of GRB 051111 obtained with the HIRES spectrograph on the Keck I 10-m telescope. The spectrum exhibits three redshifted absorption systems with the…