相关论文: Gaussian Process Inference of Stochastic Magneto-A…
We present the first optical ($BVR$) polarimetric observations of Swift J1727.8$-$1613 during its 2023--2024 outburst. Observations were performed during the X-ray hard-to-soft state transition, the soft state and the decaying hard state of…
We present a detailed analysis of the evolution of type-C quasiperiodic oscillations (QPOs) observed during the flaring state of the recently discovered black hole X-ray binary Swift J1727.8-1613, utilizing data from the Insight Hard X-ray…
The black hole candidates exhibit fast variability of their X-ray emission on a wide range of timescales. The short, coherent variations, with frequencies above 1 Hz, are referred to as quasi-periodic oscillations, and are generally…
The transient Galactic black hole candidate Swift J151857.0-572147 went through an outburst in March 2024 for the first time. Using publicly archived {\it Insight}-HXMT data, we have analyzed the timing and spectral properties of the…
We report on the detection of optical/near-infrared (O-IR) quasi-periodic oscillations (QPOs) from the black hole X-ray transient Swift J1727.8-1613. We obtained three X-ray and O-IR high-time-resolution observations of the source during…
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…
We examine stochastic variability in the dynamics of X-ray emission from the black hole system GRS 1915+105, a strongly variable microquasar commonly used for studying relativistic jets and the physics of black hole accretion. The analysis…
We report results from joint NuSTAR, Swift and XMM-Newton observations of the newly discovered black hole X-ray binary candidate Swift J1658.2-4242 in the intermediate state. We observe a peculiar event in this source, with its X-ray flux…
We report the first detection of evolving Low-Frequency Quasi-periodic Oscillation (LFQPO) frequencies in hard X-rays upto $100$ keV with $AstroSat/LAXPC$ during `unusual' outburst phase of Swift J1727.8-1613 in hard-intermediate state…
During the bright outburst in 2011, the black hole candidate IGR J17091-3624 exhibited strong quasi-periodic flare-like events (on timescales of tens of seconds) in some characteristic states, the so-called heartbeat state. From the…
We report a discovery of low-frequency quasi periodic oscillation at 0.3-0.7 Hz in the power spectra of the accreting black hole GRS1739-278 in the hard-intermediate state during its 2014 outburst based on the ${\it NuSTAR}$ and Swift/XRT…
High angular resolution radio observations of relativistic jets are necessary to understand the causal connection between accretion and jet ejection in low mass X-ray binaries. Images from these observations can be difficult to reconstruct…
RX J1301.9+2747 is an ultrasoft active galactic nucleus (AGN) with unusual X-ray variability that is characterized by a long quiescent state and a short-lived flare state. The X-ray flares are found to recur quasi-periodically on a…
IGR J17091-3624 is a black hole X-ray binary (BHXB), often referred to as the 'twin' of GRS 1915+105 because it is the only other known BHXB that can show exotic 'heartbeat'-like variability that is highly structured and repeated. Here we…
The Black Hole Binary source Swift J175.5-0127 remained in outburst for $\sim$ 12 years from May 2005 to April 2017. For most part of the outburst, the source remained in the Low Hard State (LHS) displaying transitions to softer states only…
Propagating fluctuations within accretion disks are known to induce multi-wavelength variability across diverse timescales. While these fluctuations have been widely invoked to explain rapid timing phenomena within the inner disk region in…
We present the observational results from a detailed timing analysis of the black hole candidate Swift J1658.2-4242 during its 2018 outburst with the observations of Hard X-ray Modulation Telescope (Insight-HXMT), Neutron Star Interior…
In this work I report on the stochastic X-ray variability of the 340 Hz accreting millisecond pulsar MAXI J0911-655. Analyzing pointed observations of the XMM-Newton and NuSTAR observatories I find that the source shows broad band-limited…
This work presents an investigation of the stochastic X-ray variability from the 164 Hz accreting millisecond pulsar IGR J17062-6143, based on regular observations collected with the Neutron Star Interior Composition Explorer between 2017…
This is the first of two papers in which we address the physics of the low-frequency Quasi-Periodic Oscillation (QPO) of X-ray binaries, in particular those hosting a black hole. We discuss and repeat the recent analysis and spectral…