Related papers: Long-term Optical Observations of the Be/X-ray Bin…

We report the results of eROSITA and NICER observations of the June 2020 outburst of the Be/X-ray binary pulsar RX J0529.8-6556 in the Large Magellanic Cloud, along with the analysis of archival X-ray and optical data from this source. We…

Radial-velocity variations of the H-alpha emission measured on the steep wings of the H-alpha line, prewhitened for the long-time changes, vary periodically with a period of (218.025 +/- 0.022)d, confirming the suspected binary nature of…

Type-I X-ray bursts are thermonuclear explosions occurring in the surface layers of accreting neutron stars. These events are powerful probes of the physics of neutron stars and their surrounding accretion flow. We analyze a very energetic…

We report on the RXTE detection of a sudden increase in the absorption column density, $N_\mathrm{H}$, during the 2011 May outburst of GX 304-1. The $N_\mathrm{H}$ increased up to ${\sim}16\times 10^{22}$ atoms cm$^{-2}$, which is a factor…

This study investigates the timing and spectral characteristics of X-ray bursts from the neutron star system EXO 0748-676 using the NuSTAR observatory's FPMA and FPMB instruments in the 3-79 keV range. We identify Type I X-ray bursts driven…

We report on the discovery of X-ray pulsations in the Be/X-ray binary IGR J21343+4738 during an XMM-Newton observation. We obtained a barycentric corrected pulse period of 320.35+-0.06 seconds. The pulse profile displays a peak at low…

We report on the XMM-Newton observation of the Be/neutron star X-ray binary system RX J0146.9+6121, a long period (~ 23 m) pulsar in the NGC 663 open cluster. The X-ray luminosity decreased by a factor two compared to the last observation…

From late September 2017 to February 2018, the Be X-ray binary (BeXB) Swift J0243.6+6124 underwent an unprecedently bright giant outburst. The reported X-ray luminosities were so high that the system was classified as an Ultraluminous X-ray…

4u 0115+63 is one of the most active and best studied Be/X-ray transients. Previous studies of 4u0115+63 have led to the suggestion that it undergoes relatively fast quasi-cyclic activity. However, due to the lack of good coverage of the…

The emission-line Be star HD 215227 lies within the positional error circle of the newly identified gamma-ray source AGL J2241+4454. We present new blue spectra of the star, and we point out the morphological and variability similarities to…

We have studied the very long-term temporal properties of the optical emission from Be X-ray binaries (BeX) in the Small Magellanic Cloud over a ~ 16 yr baseline, using light curves from the MACHO and OGLE databases. All the BeX in our…

X-ray transients, such as accreting neutron stars, periodically undergo outbursts, thought to be caused by a thermal-viscous instability in the accretion disk. Usually outbursts of accreting neutron stars are identified when the accretion…

Be X-ray binaries (BeXRBs) may show strong X-ray and optical variability, and can exhibit some of the brightest outbursts that break through the Eddington limit. Major X-ray outbursts are often accompanied by strong optical flares that…

We report results of Swift observations for the high mass Be/X-ray binary system 1A 1118-615, during an outburst stage in January, 2009 and at a flaring stage in March, 2009. Using the epoch-folding method, we successfully detected a pulsed…

The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously…

The [Ne II] fine-structure emission line at 12.8 micron has been detected in several young stellar objects (YSO) spectra. This line is thought to be produced by X-ray irradiation of the warm protoplanetary disk atmospheres, however the…

We analyse the spectroscopic and photometric variability of the Oe star HD 60848 over the last twenty five years. The spectra reveal recurrent, but irregular cycles of increased circumstellar emission lines. These cycles are highly…

We investigate the long-term optical variability of the Be/X-ray binary GRO J2058+42 and the possible connection with periods of enhanced X-ray activity. We performed an optical spectroscopic and photometric analysis on data collected…

We report XTE and SAX observations of the X-ray pulsar RX J0146.9+612, the neutron star/Be binary system with the longest known spin period. Data obtained one month after the most recent outburst (July 1997), show that the source has…

We present spin-resolved X-ray data of the neutron star binary Her X-1 taken using the EPIC detectors on XMM-Newton. The data were taken at three distinct epochs through the 35 day precession period. The energy dependent light curves of…