We discuss the properties of 137 cataclysmic variables (CVs) which are included in the Sloan Digital Sky Survey (SDSS) spectroscopic data base, and for which accurate orbital periods have been measured. 92 of these systems are new discoveries from SDSS and were followed-up in more detail over the past few years. 45 systems were previously

We report on optical and near-infrared observations obtained during and after the 2004 December discovery outburst of the X-ray transient and accretion-powered millisecond pulsar IGR J00291+5934. Our observations monitored the evolution of the brightness and the spectral properties of IGR J00291+5934 during the outburst decay toward quiescence. We

We identify HS 2325+8205 as an eclipsing, frequently outbursting, dwarf nova with an orbital period of Porb = 279.841731(5) minutes. Spectroscopic observations are used to derive the radial velocity curve of the secondary star from absorption features and also from the Hα emission lines, originating from the accretion disk, yielding Ksec = Kabs =

We present the results of time-resolved optical photometry and spectroscopy of the X-ray transient XTE J1859+226 (V406 Vul). Photometric observations taken during 2000 and 2008 reveal the presence of the secondary star's ellipsoidal modulation. Further photometry obtained in 2010 shows the system ≃1 mag brighter than its quiescence level and the

We present a study of the flickering activity in two nova-like systems, KR Aur and UU Aqr. We applied a statistical model of flickering simulations in accretion discs based on turbulent angular momentum transport between two adjacent rings with an exponential distribution of the turbulence dimension scale. The model is based on a steady-state disc

Context. The link between how bipolar planetary nebulae are shaped and their central stars is still poorly understood. Aims: This paper investigates the kinematics and shaping of the multipolar nebula M 1-75, and briefly discusses the location and nature of its central star. Methods: Fabry-Perot data from GHαFAS on the WHT that samples the Doppler

We present a new eclipsing post-common-envelope binary, identified inside the Kepler field prior to the launch of the spacecraft. Multifilter photometry and radial velocity data are analysed with an eclipsing-binary modelling code to determine the physical parameters of the binary. Spectra of the system within the primary eclipse and uneclipsed

Context. After years of modest optical activity, the quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum, renewing interest in this source. Aims: We present the results of low-energy multifrequency monitoring by the GLAST-AGILE Support Program (GASP) of

Context. The sudden optical brightening of two young stellar objects, HBC 722 and VSX J205126.1+440523, located in the North America/Pelican Nebula Complex, was announced in August 2010. Early photometric and spectroscopic observations of these objects indicated that they may belong to the FUor or EXor class of young eruptive stars. The eruptions

EX Lup is the prototype of the EXor class of eruptive young stars. These objects show optical outbursts which are thought to be related to runaway accretion onto the star. In a previous study we observed in situ crystal formation in the disk of EX Lup during its latest outburst in 2008, making the object an ideal laboratory to investigate

Context. The discovery of new massive star clusters and massive stellar populations in previously known clusters in our Galaxy by means of infrared studies has changed our view of the Milky Way from an inactive to an active star-forming machine. Within this scenario, we present a near-infrared spectrophotometric study of the stellar content of the

Aims: The characterisation of the stellar population in young high-mass star-forming regions allows fundamental cluster properties like distance and age to be constrained. These are essential when using high-mass clusters as probes for conducting Galactic studies. Methods: NGC 7538 is a star-forming region with an embedded stellar population

Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying and interpreting variability on a decadal timescale, here we present a mid-infrared spectral atlas containing

We performed J- and R-band linear polarimetry with the 4.2 m William Herschel Telescope at the Observatorio del Roque de los Muchachos and with the 1.6 m telescope at the Observatório do Pico dos Dias, respectively, to derive the magnetic field geometry of the diffuse molecular cloud surrounding the embedded protostellar system NGC 1333 IRAS 4A. We

Context. The dark cloud Lynds 723 (L723) is a low-mass star-forming region where one of the few known cases of a quadrupolar CO outflow has been reported. Two recent works have found that the radio continuum source VLA 2, towards the centre of the CO outflow, is actually a multiple system of young stellar objects (YSOs). Several line-emission

We conducted a long-term optical photometric and spectroscopic monitoring of the strongly variable, accreting young sun-like star [KOS94] HA11, associated with the dark cloud Lynds 1340 that exhibited large amplitude (5-6 mag in the I C band) brightness variations on 2-3 years timescales, flat spectral energy distribution (SED), and extremely