20 citations · 60 across the 14 of their papers we have counts for
14 papers
Model dependence of XRISM black-hole spin constraints in Cyg X-1
Andrzej A. Zdziarski, Swadesh Chand, Michal Szanecki +2
We study the persistent black hole X-ray binary Cyg X-1, recently observed by XRISM Resolve and simultaneously by NICER and NuSTAR in its hard spectral state. We confirm the result…
Accretion Geometry of the New Galactic Black Hole Candidate AT2019wey in the Hard State
Pragati Sahu, Swadesh Chand, Gulab C. Dewangan +3
We perform broadband spectral and timing studies of the Galactic low-mass black hole candidate AT2019wey using quasi-simultaneous NICER, Swift, and NuSTAR observations obtained in…
Evolution of the Inner Accretion Flow in Swift J1727.81613 across Intermediate States: Insights from Broadband Spectral and Timing Analysis
Swadesh Chand, Andrzej A. Zdziarski, Gulab C. Dewangan +1
We present a comprehensive broadband spectral and variability study of the newly detected black hole X-ray binary Swift~J1727.8--1613 in the intermediate states during its 2023 out…
The strong Fe K line and spin of the black-hole X-ray binary MAXI J1631-479
Andrzej A. Zdziarski, Swadesh Chand, Gulab Dewangan +5
We study the transient black hole binary MAXI J1631--479 in its soft spectral state observed simultaneously by the NICER and NuSTAR instruments. Its puzzling feature is the presenc…
2017 Outburst of H 1743-322: AstroSat and Swift View
Pragati Sahu, Swadesh Chand, Parijat Thakur +4
We perform a comprehensive timing and broadband spectral analysis using an AstroSat observation of the low-mass black hole X-ray binary H~1743--322 during 2017 outburst. Additional…
Accretion Geometry of GX 339-4 in the Hard State: AstroSat View
Swadesh Chand, Gulab C. Dewangan, Andrzej A. Zdziarski +3
We perform broadband ( keV) spectral analysis of five hard state observations of the low-mass back hole X-ray binary GX~339--4 taken by AstroSat during the rising phase of…
What Is the Black Hole Spin in Cyg X-1?
Andrzej A. Zdziarski, Swadesh Chand, Srimanta Banerjee +6
We perform a detailed study of the black hole spin of Cyg X-1, using accurate broad-band X-ray data obtained in the soft spectral state by simultaneous NICER and NuSTAR observation…
Black hole spin measurements in LMC X-1 and Cyg X-1 are highly model-dependent
Andrzej A. Zdziarski, Srimanta Banerjee, Swadesh Chand +4
The black-hole spin parameter, , was measured to be close to its maximum value of 1 in many accreting X-ray binaries. In particular, was found in a number of…
AstroSat view of the newly discovered X-ray transient MAXI~J1803--298 in the Hard-intermediate state
Swadesh Chand, G. C. Dewangan, Parijat Thakur +2
We perform comprehensive temporal and spectral analysis of the newly discovered X-ray transient MAXI~J1803--298 using an AstroSat target of opportunity observation on May 11, 2021…
AstroSat Observation of 2016 Outburst of H 1743-322
Swadesh Chand, V. K. Agrawal, G. C. Dewangan +2
We present the detection of type C quasi-periodic oscillation (QPO) along with upper harmonic at respective frequencies of Hz and Hz in the single AstroSat obse…
Are There Transit Timing Variations for the Exoplanet Qatar-1b ?
Li-Hsin Su, Ing-Guey Jiang, Devesh P. Sariya +11
Motivated by the unsettled conclusion on whether there are any transit timing variations (TTVs) for the exoplanet Qatar-1b, 10 new transit light curves are presented and the TTV an…
Non-Sinusoidal Transit Timing Variations for the Exoplanet HAT-P-12b
Devesh P. Sariya, Ing-Guey Jiang, Li-Hsin Su +14
Considering the importance of investigating the transit timing variations (TTVs) of transiting exoplanets, we present a follow-up study of HAT-P-12b. We include six new light curve…
Investigating Extra-solar Planetary System Qatar-1 through Transit Observations
Parijat Thakur, Vineet Kumar Mannaday, Ing-Guey Jiang +2
We report the results of the transit timing variation (TTV) analysis of the extra-solar planet Qatar-1b using thirty eight light curves. Our analysis combines thirty five previousl…
2016 outburst of H~1743--322: \textit{XMM-Newton} and \textit{NuSTAR} view
Swadesh Chand, V. K. Agrawal, G. C. Dewangan +2
We report the detection of type C QPO along with the upper harmonic in the commensurate ratio of 1:2 in the two observations of the low-mass black hole transient H~1743--322 jointl…