Related papers: Optical Modulation in the X-Ray Binary 4U 1543-624…
We report on Nuclear Spectroscopic Telescope Array (NuSTAR), Neil Gehrels Swift Observatory (Swift) X-ray Telescope (XRT) and Swift Burst Alert Telescope (BAT) observations of IGR J16493-4348, a wind-fed Supergiant X-ray Binary (SGXB)…
The formation of ultra-compact X-ray binaries (UCXBs) has not been well understood. Previous works show that ultra-short orbital periods ($<1$ hr) may be reached through mass transfer driven by magnetic braking in normal…
We report on a pair of X-ray Multi-Mirror Mission (XMM-Newton) observations of the Supergiant X-ray binary 4U 1909+07, which were performed on 2021 October 3 and 2021 October 8, respectively. We measure the neutron star rotation period in…
The X-ray source 2S0114+650=LSI+65 010 is a binary system containing a B-type primary and a low mass companion believed to be a neutron star. The system has three reported periodicities: the orbital period, P{orb}~11.6 d, X-ray flaring with…
We present results of optical and infrared photometric monitoring of the eclipsing low-mass X-ray binary V395 Car (2S 0921-630). Our observations reveal a clear, repeating orbital modulation with an amplitude of about one magnitude in B,…
We report on the long term stability of the millisecond oscillations observed with the Rossi X-ray Timing Explorer (RXTE) during thermonuclear X-ray bursts from the low mass X-ray binaries (LMXB) 4U 1728-34 and 4U 1636-53. We show that…
We report on analysis of X-ray, optical and radio observations of the previously overlooked X-ray source 2CXO\,J174517.0$-$321356 located just 3.2$^{\circ}$ away from the Galactic center. Timing analysis of X-ray observations of the source…
We review X-ray flux modulation from X-ray binaries on time scales corresponding to the orbital period and those at longer time scales (so called superorbital). Those modulations provide a powerful tool to constrain geometry of the…
(Abridged) We present results of several X-ray observations of the X-ray binary 4U 1954+31 performed with the satellites BeppoSAX, EXOSAT, ROSAT, RXTE, and Swift. We also studied the RXTE ASM data over a period of more than 10 years. Light…
A set of CCD images have been obtained during the decline of the X-ray transient SAX J1808.4-3658 during April-June 1998. The optical counterpart has been confirmed by several pieces of evidence. The optical flux shows a modulation on…
We study the formation of neon-enriched donor stars in ultracompact X-ray binaries (orbital periods P<80 min) and show that their progenitors have to be low-mass (0.3 - 0.4 solar mass) ``hybrid'' white dwarfs (with CO cores and thick helium…
The high-mass X-ray binary (HMXB) SMC X-1 exhibits a superorbital modulation with a dramatically varying period ranging between ~40 d and ~60 d. This research studies the time-frequency properties of the superorbital modulation of SMC X-1…
A binary in which a slightly evolved star starts mass transfer to a neutron star can evolve towards ultra-short orbital periods under the influence of magnetic braking. This is called magnetic capture. We investigate in detail for which…
It has been proposed that RX J1914.4+2456 is a stellar binary system with an orbital period of 9.5 mins. As such it shares many similar properties with RX J0806.3+1527 (5.4 mins). However, while the X-ray spectrum of RX J0806.3+1527 can be…
IGR J17062-6143 is an ultra-compact X-ray binary (UCXB) with an orbital period of 37.96 min. It harbours a millisecond X-ray pulsar that is spinning at 163 Hz and and has continuously been accreting from its companion star since 2006.…
We report the discovery of a broad emission feature at ~0.7 keV in the spectra of the ultra-compact X-ray binary 4U 1543-624, obtained with the high-resolution spectrographs of the XMM-Newton and Chandra satellites. We confirm the presence…
We report the results obtained with a XMM-Newton observation, performed in April 2023, of the poorly known Galactic Be X-ray binary pulsar 4U 0728-25. It was revealed at a flux level (not corrected for the absorption) $f_{\rm X}$(0.2-12…
The hard X-ray source 4U 2206+54 is a peculiar high mass X-ray binary with a main-sequence donor star. Recent X-ray observations suggested that the compact object in 4U 2206+54 may be a neutron star. The X-ray emission comes from the…
4U 1210-64 has been postulated to be a High-Mass X-ray Binary powered by the Be mechanism. X-ray observations with Suzaku, the ISS Monitor of All-sky X-ray Image (MAXI) and the Rossi X-ray Timing Explorer Proportional Counter Array (PCA)…
We studied the spectral changes of the high-mass X-ray binary system LMC X-4 to understand the origin and mechanisms beyond its super-orbital modulation (30.4 days). To this aim, we obtained a monitoring campaign with Swift/XRT (0.3-10 keV)…