Swift J1357.2-0933: a massive black hole in the Galactic thick disc
Swift J1357.2-0933 is one of the shortest orbital period black hole X-ray transients. It exhibited deep optical dips together with an extremely broad H α line...
Swift J1357.2-0933 is a confirmed very faint black hole X-ray transient and has a short estimated orbital period of 2.8 h. We observed Swift J1357.2-0933 for...
Swift observations of V404 Cyg during the 2015 outburst: X-ray outflows from super-Eddington accretion
The black hole (BH) binary V404 Cyg entered the outburst phase in 2015 June after 26 yr of X-ray quiescence, and with its behaviour broke the outburst evolution...
Swift/XRT, Chandra, and XMM-Newton observations of IGR J17091-3624 as it returns into quiescence
IGR J17091-3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system...
SWSextantis stars: the dominant population of cataclysmic variables with orbital periods between 3 and 4h
We present time-series optical photometry of five new cataclysmic variables (CVs) identified by the Hamburg Quasar Survey (HQS). The deep eclipses observed in...
Intermediate-resolution (0.5-1 Å) optical spectroscopy of the cataclysmic variable (CV) SY Cnc reveals the spectrum of the donor star. Our data enable us to...
Symbiotic binaries in the Gaia data ─ I. Known symbiotics in DR3 and FPR
Symbiotic stars are long-period interacting binaries composed of an evolved giant and a hot compact companion. Their complex spectra and variability make them...
Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variability
In 2015 July 29-September 1, the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 h. During one of these epochs...