Related papers: A transient low-frequency QPO from the black hole …
In this work, we report for the first time two repeated quasi-periodic oscillations (QPOs) in the light curve of the Flat Spectrum Radio Quasar (FSRQ) S5 1044+71. This source was observed by the Transiting Exoplanet Survey Satellite (TESS)…
GRS 1915+105 is a black hole X-ray binary exhibiting quasi-periodic $\rho$-class ("heartbeat") oscillations with periods of $\sim$50-100 s, thought to arise from radiation-pressure-driven instabilities in the inner accretion disk at…
Fast transitions between different types of power density spectra (PDS) happening over timescales of several tens of seconds are rare phenomena in black hole X-ray binaries. In this paper, we report a broadband spectral-timing analysis of…
We have analyzed publicly available RXTE/PCAs archival data of GRS 1915+105 during its burst/flaring state. The burst cycle ranges from 30 to 1300 s. These bursts are different from the type I and type II classical bursts seen in Low Mass…
We report the discovery with XMM-Newton of an approximately 7 mHz X-ray (0.3-10.0 keV) quasi-periodic oscillation (QPO) from the eclipsing, high-inclination black hole binary IC 10 X-1. The QPO is significant at > 4.33 sigma confidence…
Spectral-timing analysis of the fast variability observed in X-rays is a powerful tool to study the physical and geometrical properties of the accretion/ejection flows in black-hole binaries. The origin of type-B quasi-periodic oscillations…
I summarize recent near-infrared spectroscopy of the microquasar GRS 1915+105 with the ESO/VLT which allowed to (i) identify the donor and (ii) measure the orbital period and radial velocity amplitude. Assuming that the jet ejections occur…
We present the results of a detailed analysis of RXTE observations of class $\omega$ which show an unusual state transition between high-soft and low-soft states in the microquasar GRS 1915+105. Out of about 600 pointed RXTE observations,…
We report the discovery with the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) of a 450 Hz quasiperiodic oscillation (QPO) in the hard X-ray flux from the galactic microquasar GRO J1655-40. This is the…
We report the detection of high frequency variability in the black hole X-ray transient XTE J1650-500. A quasi-periodic oscillation (QPO) was found at 250 Hz during a transition from the hard to the soft state. We also detected less…
(abridged) Two XMM-Newton observations of the black-hole binary GRS1915+105 were triggered in 2004, during a long "plateau" state of the source. (...) While the light curves show just small amplitude variations (a few percent) at timescales…
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT, NICER and MAXI. This outburst can be classfied roughly into…
In this work, we have searched quasi-periodic oscillations (QPOs) in the 15 GHz light curve of the FSRQ PKS J0805-0111 monitored by the Owens Valley Radio Observatory (OVRO) 40 m telescope during the period from January 9,2008 to May…
The X-ray burster and dipper 4U1915-05 (also known as XB1916-053) was observed 19 times for a total exposure of roughly 140 ks between 1996 February and October with the proportional counter array (PCA) aboard Rossi X-ray Timing Explorer…
We discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the bright low-mass X-ray binary and Z source GX 5-1 with the Rossi X-ray Timing Explorer. In the X-ray color-color and hardness-intensity diagram a clear Z track is…
We have analyzed ~600 ks of Rossi X-ray Timing Explorer data of the neutron star low-mass X-ray binary and Z source GX 17+2. A study was performed of the properties of the noise components and quasi-periodic oscillations (QPOs) as a…
We investigated the snapshots of five NICER observations of the black hole transient GX 339-4 when the source transited from the hard state into the soft state during its outburst in 2021. In this paper, we focused our study on the…
The burster and dipper Low Mass X-ray Binary (LMXB) 4U1915-05 (also known as XB1916-053) was observed by the Rossi X-ray Timing Explorer (RXTE) 19 times for a total exposure of 140 ks between 1996 February and October. Here we report on the…
We report the discovery of twin kHz quasi-periodic oscillations (QPOs) in the persistent X-ray flux of the new X-ray transient XTE J2123-058. We detected the QPOs in data taken with the proportional counter array on board the Rossi X-ray…
The type I X-ray burster and dipper 4U1915-05 (also known as XB1916-053) was monitored by the Rossi X-ray Timing Explorer between February and October, 1996. The source was observed in various spectral states; the highest luminosity state…