Related papers: The eclipsing X-ray pulsar X-7 in M33
M31 UCXB-1 is one of the brightest X-ray point sources in the bulge of M31, with a peak X-ray luminosity $ L_{\mathrm{0.5-10 \: keV}} = 2.9^{+0.2}_{-0.2} \times 10^{38} \: \mathrm{erg} \: \mathrm{s}^{-1} $. Both XMM-Newton and Chandra…
While the distribution of spin periods of High Mass X-ray Binaries (HMXBs) spans more than four orders of magnitude (69ms - 25min), the few known X-ray pulsars accreting from very low mass companions (<1 Msun) have very similar periods…
We present an optical and X-ray study of four Be/X-ray binaries located in the Small Magellanic Cloud (SMC). OGLE I-band data of up to 11 years of semi-continuous monitoring has been analysed for SMC X-2, SXP172 and SXP202B, providing both…
XMM-Newton archival observations of the Be/X-ray binary candidate RX J0103.6-7201 revealed pulsations with a period of ~1323 s. This makes RX J0103.6-7201 the X-ray pulsar with the longest period known in the Small Magellanic Cloud (SMC).…
We present new photometric and spectroscopic observations of the transient supersoft X-ray source RX J0537.7-7034 and find a periodicity of approximately 3.5 hrs. This establishes RX J0537.7-7034 as the supersoft X-ray source with the…
Ultra-luminous X-Ray Objects are off-nucleus point sources with $L_X=10^{39}$-$10^{41}$ erg/s but the nature of such systems are largely unidentified. Here we report a 2.1 hour period observed in a Chandra ACIS observation for ULX M51 X-7,…
We present the results of an in-depth study of the long-period X-ray pulsar GX 301-2. Using archival data of INTEGRAL, RXTE ASM, and CGRO BATSE, we study the spectral and timing properties of the source. Comparison of our timing results…
We have investigated the temporal variability of the X-ray flux measured from the high-mass Xray binary LMCX-4 on time scales from several tens of days to tens of years, i.e., exceeding considerably the orbital period (1.408 days). In…
A pulse timing orbit has been obtained for the X-ray binary XTE J1855-026 using observations made with the Proportional Counter Array on board the Rossi X-ray Timing Explorer. The mass function obtained of ~16Mo together with the detection…
We report the discovery of an eclipsing X-ray binary with a 3.62-hr period within 24" of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary, and allows for a few…
XTE J1710-281 is a transient eclipsing binary system with a period close to 3.28 hours, hosting a neutron star. The average eclipse duration is 420 seconds, and eclipse arrival times reported in the literature span from 1999 to 2017. A…
We present X-ray observations of the "redback" eclipsing radio millisecond pulsar and candidate radio pulsar/X-ray binary transition object PSR J1723-2837. The X-ray emission from the system is predominantly non-thermal and exhibits…
We report here results from pulse arrival time delay analysis of the eclipsing high mass X-ray binary pulsar LMC X-4 using observations made with the Rossi X-ray Timing Explorer, XMM-Newton, NuSTAR and AstroSat. Combining the orbital…
We have obtained snapshot images of a transient X-ray source in M31 from Chandra ACIS-I and the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The Chandra position of the X-ray nova was R.A.=00:42:56.038 +/-0.08'',…
The high-mass X-ray binary SMC X-1 is an eclipsing binary with an orbital period of 3.89 d. This system exhibits a superorbital modulation with a period varying between ~40 d and ~65 d. The instantaneous frequency and the corresponding…
We have analysed archival {\it ROSAT} PSPC data for M32 in order to study the x-ray emission from this nearest elliptical galaxy. We fit spectra from three long exposures with Raymond-Smith, thermal bremsstrahlung, and power-law models. All…
Observations of the 297 s X-ray pulsar 1E1145.1-6141 with the Rossi X-Ray Timing Explorer have revealed its 14.4 d eccentric orbit around its B supergiant companion. The best-fit orbital elements are: P_orb = 14.365(2) d, a_x sin i=99.4(18)…
On 28 February 2007 a new outburst of the previously known transient source XTE J1856+053 was detected with RXTE/ASM. We present here the results of an XMM-Newton (0.5-10.0 keV) Target of Opportunity observation performed on 14 March 2007,…
The neutron star X-ray transient MAXI J1807+132 has undergone outbursts in 2017, 2019, and 2023. We conducted an $R$-band time series photometry campaign using the Isaac Newton Telescope during the 2022 quiescent state. We detected a…
We report spectral and variability analysis of two quiescent low mass X-ray binaries (X5 and X7, previously detected with the ROSAT HRI) in a Chandra ACIS-I observation of the globular cluster 47 Tuc. X5 demonstrates sharp eclipses with an…