Double-peaked line profiles are commonly considered a hallmark of rotating discs, with the distance between the peaks a measure of the rotation velocity...
RXJ 0921+4529: A Binary Quasar or a Gravitational Lens?
We report the new spectroscopic observations of the gravitational lens RXJ 021+4529 with the multi-mode focal reducer SCORPIO of the SAO RAS 6 m telescope. The...
San Pedro Mártir observations of microvariability in obscured quasars
Fast brightness variations are a unique tool to probe the innermost regions of active galactic nuclei (AGN). These variations are called microvariability or...
The last years saw numerous detections of substructure in the Galactic halo, largely due to wide area surveys like the Sloan Digital Sky Survey (SDSS) or the...
SDSS J0909+4449: A large-separation strongly lensed quasar at z ˜ 2.8 with three images
We report the discovery of SDSS J0909+4449, an exceptional system consisting of a quasar at z = 2.788 strongly lensed by a group of galaxies at z ˜ 0.9 into...
Search for very high energy gamma-rays from the z = 0.896 quasar 4C +55.17 with the MAGIC telescopes
The bright gamma-ray quasar 4C +55.17 is a distant source (z = 0.896) with a hard spectrum at GeV energies as observed by the Large Area Telescope (LAT) on...
Serendipitous Discovery of a Projected Pair of QSOs Separated by 4.5 arcsec on the Sky
We present the serendipitous discovery of a projected pair of quasi-stellar objects (QSOs) with an angular separation of Δθ = 4.50 arcsec. The redshifts of the...
SHARDS: A Global View of the Star Formation Activity at z ~ 0.84 and z ~ 1.23
In this paper, we present a comprehensive analysis of star-forming galaxies (SFGs) at intermediate redshifts (z ∼ 1). We combine the ultra-deep optical spectro...
Short time-scale fluctuations in the difference light curves of QSO 0957+561A,B: microlensing or noise?
From optical R-band data of the double quasar QSO 0957+561A,B, we made two new difference light curves (with an overlap of about 330d between the time-shifted...