13 papers
Extreme Variability Reveals How the Eddington Ratio Regulates Coronal Power in Active Galactic Nuclei
Arghajit Jana, Claudio Ricci, Franz E. Bauer +13
The bolometric luminosity () of active galactic nuclei (AGNs) is a key tracer of accretion physics, but its direct determination is often hindered by limited spectral…
Multimission Observations of GS 1354-64 during the 2025-2026 Outburst: First Results
Dipak Debnath, Hsiang-Kuang Chang, Subham Srimani +1
The Galactic transient black hole GS 1354-64 recently showed a new outburst, which has been continuously monitored by {\it MAXI}, {\it NuSTAR} and {\it Insight-HXMT} missions. The…
Bridging X-ray Polarization with Timing & Spectroscopic Parameters of a galactic black hole: Swift J1727.8-1613
Arka Chatterjee, Sujoy K. Nath, Kaushik Chatterjee +5
We report the discovery of a correlated energy-dependent time lag and degree of polarization for Swift J1727.8-1613 during its 2023 outburst. The energy-dependent time lag is measu…
Evolution of Time-Lags of Swift J1727.8-1613 during the Rising Phase of Its Discovery Outburst
Sujoy Kumar Nath, Dipak Debnath, Hsiang-Kuang Chang
We investigate the accretion dynamics of the black hole X-ray binary Swift J1727.8-1613 during its discovery outburst that lasted for months. Insight-HXMT moni…
Observational Relationship between Spectral Properties of Gamma-ray and X-ray Emissions from Pulsars
Ashwin Aravindaraj, Hsiang-Kuang Chang
Correlations between gamma-ray and X-ray spectral properties of pulsars are investigated in order to provide observational hints on physics involved in pulsars' high-energy emissio…
Multi-wavelength properties of changing-state active galactic nuclei: I. the evolution of soft excess and X-ray continuum
Arghajit Jana, Claudio Ricci, Alessia Tortosa +11
Changing-state active galactic nuclei (CSAGNs) exhibit rapid variability, with mass accretion rates that can change by several orders of magnitude in a few years. This provides us…