Related papers: Orbital Parameters for the Black Hole Binary XTE J…
The X-ray transient Swift J1727.8-1613 ended its 10-month discovery outburst on June of 2024, when it reached an optical brightness comparable to pre-discovery magnitudes. With the aim of performing a dynamical study, we launched an optical…
PSR J1641+8049 is a 2 ms black widow pulsar with the 2.2 h orbital period detected in the radio and $\gamma$-rays. We performed new phase-resolved multi-band photometry of PSR J1641+8049 using the OSIRIS instrument at the Gran Telescopio…
We present HST, RXTE, and UKIRT observations of the broad band spectra of the black hole X-ray transient XTE J1859+226 during the decline from its 1999-2000 outburst. Our UV spectra define the 2175A interstellar absorption feature very well…
We report phase-resolved optical polarimetric, photometric and spectroscopic observations of RX J2115.7-5840 (= EUVE J2115-58.6, Craig 1996) which confirms the system to be a magnetic cataclysmic binary of the polar (AM Herculis) subclass.…
The degree to which the thin accretion disks of black hole X-ray binaries are truncated during hard spectral states remains a contentious open question in black hole astrophysics. During its singular observed outburst in…
We fit the broad-band X/gamma-ray spectrum (0.8-1000 keV) of the accreting black hole XTE J1550-564 in the very high state. The quasi-simultaneous data from ASCA, RXTE and OSSE show that the disc is strongly Comptonized, with a high energy…
We use gravitational microlensing of the four images of the z=0.658 quasar RXJ1131-1231 to measure the sizes of the optical and X-ray emission regions of the quasar. The (face-on) scale length of the optical disk at rest frame 400 nm is 1.3…
Context. NGC 300 X-1 is the second extragalactic candidate, after IC 10 X-1, in the rare class of Wolf-Rayet/compact object X-ray binary systems exemplified in the Galaxy by Cyg X-3. From a theoretical point of view, accretion onto a black…
MAXI J1659-152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a black hole as the most likely compact object. Dips in the X-ray…
We report spectral results from three BeppoSAX observations of the black hole candidate XTE J1650-500 during its 2001/2002 outburst. We find strong evidence for the presence of a broad and strongly relativistic Fe emission line. The line…
We report on the first continuous, 80 day optical monitoring of the transitional millisecond pulsar PSR J1023+0038 carried out in mid-2017 with Kepler in the K2 configuration, when an X-ray subluminous accretion disk was present in the…
We report on the discovery of a new pulsating X-ray source during Rossi X-ray Timing Explorer observations of a low galactic latitude field centered at RA (J2000) = 19 hr 05 m 43 s and Dec (J2000) = +08 deg 58 arcmin 48 arcsec. Significant…
We present a series of monitoring observations of the ultrasoft broad-line AGN RE J2248-511 with XMM-Newton. Previous X-ray observations showed a transition from a very soft state to a harder state five years later. We find that the…
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…
The highly variable blazar OJ~287 is commonly discussed as an example of a binary black hole system. The 130 year long optical light curve is well explained by a model where the central body is a massive black hole of 18.35$\times$10$^9$…
We present our analysis of the extensive monitoring of SS433 by the RXTE observatory collected over the period 1996-2005. The difference between energy spectra taken at different precessional and orbital phases shows the presence of strong…
We report on simultaneous sub-second optical and X-ray timing observations of the low mass X-ray binary black hole candidate MAXI J1820+070. The bright 2018 outburst rise allowed simultaneous photometry in five optical bands ($ugriz_s$)…
We report on the evolution of the X-ray energy spectrum for the black hole candidate (BHC) X-ray transient XTE J1550-564 during the decay of the 2000 outburst. The Rossi X-ray Timing Explorer (RXTE) and Chandra observations span nearly five…
With Rossi X-ray Timing Explorer (RXTE) data, we systematically study the cross-correlation and time lag in all spectral states of black hole X-ray binary (BHXB) XTE J1859+226 in detail during its entire 1999-2000 outburst that lasted for…
We report the detection of an orbital period decay of $\dot P=-1.83\pm0.66$ ms yr$^{-1}$ in the black hole X-ray binary XTE J1118+480. This corresponds to a period change of $-0.85\pm0.30$ $\mu $s per orbital cycle, which is $\sim 150$…