Related papers: MASTER OT J072007.30+451611.6: A Polar with Strong…

We report the discovery of a new eclipsing polar, MASTER OT J061451.70-272535.5, detected as an optical transient by MASTER auto-detection software at the recently commissioned MASTER-SAAO telescope. Time resolved (10-20 s) photometry with…

We present time-resolved photometry and spectroscopy of the recently classified polar MASTER OT J132104.04+560957.8. The spectrum shows a smooth, non-thermal continuum at the time of maximum light, without any individually discernible…

We report the discovery of a new, bright (V = 17 mag) AM Her system as the optical counterpart of the soft ROSAT All-Sky-Survey source RX J1846.9+5538 (= 1RXS J184659.4+553834). Optical photometric and spectroscopic follow-up observations…

We report the first time-resolved photometric and spectroscopic optical observations of the X-ray source RX J2133.7+5107, identified in the ROSAT survey. A clear persistent optical light pulsation is discovered with fast photometry at a…

We report the identification of the ROSAT all-sky survey source 1RXS J154814.5-452845as new intermediate polar and present the results from follow-up optical and X-ray observations. The source shows pulsations with a period of 693 s both in…

We present photometric and spectroscopic observations of the cataclysmic variable MASTER OT J132104.04+560957.8 which strongly indicate that it is a polar with an orbital period of 91 minutes. The optical light curve shows two maxima and…

We present optical photometric and spectroscopic observations, and an analysis of archival X-ray data of three polars: RX J0859.1+0537, RX J0749.1-0549, and RX J0649.8-0737. Optical light curves of these three polars reveal eclipse features…

We report optical and X-ray observations of the high-field polar RXJ1007.5-2017 performed between 1990 and 2012. It has an orbital period of 208.60 min determined from the ellipsoidal modulation of the secondary star in an extended low…

We report on optical imaging of the X-ray binary SAX J1808.4-3658 with the 8-m Gemini South Telescope. The binary, containing an accretion-powered millisecond pulsar, appears to have a large periodic modulation in its quiescent optical…

The hard X-ray source 2PBC J0658.0-1746 was proposed as an eclipsing magnetic cataclysmic variable of the polar type, based on optical follow-ups. We present the first spectral and timing analysis at X-ray energies with XMM-Newton,…

We present a detailed NIR/optical/UV study of the transient low mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, aimed at determining the nature of its companion star. We obtained three optical spectra at the 2.1…

We report on optical spectroscopic observations of the X-ray Transient XTE J1118+480 covering the period from April 7, 2000 to July 4, 2000. The spectrum is characterized by weak, broad, double-peaked Balmer and He lines on top of a blue…

We have discovered with the Wide Field Cameras on board BeppoSAX the weak transient X-ray source SAXJ2239.3+6116 whose position coincides with that of 4U2238+60/3A2237+608 and is close to that of the fast transient AT2238+60 and the…

We present the results of the new optical polarimetric observations of the superluminal source GRO J1655--40, carried out in July 1997, with the multichannel photopolarimeter of the Torino Observatory, using the 2.15-m telescope of Complejo…

We present the first optical and infrared polarimetric study of the low mass transient X-ray binary Cen X-4 during its quiescent phase. This work is aimed to search for an intrinsic linear polarisation component in the system emitted…

We report the serendipituous discovery of the new eclipsing polar 2XMMp J131223.4+173659. Its striking X-ray light curve attracted immediate interest when we were visually inspecting the source products of the 2XMMp catalogue. This light…

We present X-ray observations of the periodic optical source ZTF J185139.81+171430.3 (hereafter ZTF J1851) by the XMM, NICER and NuSTAR telescopes. The source was initially speculated to be a white dwarf (WD) pulsar system due to its short…

Detection of periodicity in the broad-band non-thermal emission of blazars has so far been proven to be elusive. However, there are a number of scenarios which could lead to quasi-periodic variations in blazar light curves. For example,…

We discovered Fe $K_{\alpha}$ complex emission and pulsation in two highly variable sources (4XMM J174917.7--283329, 4XMM J174954.6--294336). The equivalent widths of 6.4 and 6.7 keV lines of 4XMM J174917.7--283329 are $99^{+84}_{-72}$ and…

We present the results of the optical study of the new eclipsing polar Gaia23cer. We analyzed the brightness variability of the polar in high ($\langle r \rangle \approx 16.5\mathrm{\,mag}$) and low ($\langle r \rangle \approx…