6 papers
Importance and Science Outcomes from the first XSPECT/XPoSat Workshop
Anuj Nandi, Rwitika Chatterjee, V. P. Shyam Prakash +49
This paper summarizes the science outcomes of the first Workshop on Data Analysis using observations from the XSPECT payload onboard the XPoSat, which brought together early-career…
A Calibration Audit of a Gaia XP White-Dwarf Main-Sequence Binary Catalog: How Much the BP-Band Residual Contaminates at Its Bound and Above
Karan Akbari
A Gaussian-process classifier on Gaia DR3 XP spectra produced 30,000 white-dwarf main-sequence binary candidates (Li et al. 2025), with probabilities but no likelihood. The c…
What an Amortized X-ray Posterior Cannot See: Gain Shifts, Silent Miscalibration, and the Limits of the Evidence Check
Karan Akbari
Neural posterior estimation (NPE) gives X-ray spectral fits a posterior in milliseconds instead of the minutes nested sampling costs, but without its calibration guarantee or goodn…
Probing heartbeat oscillations from the black hole X-ray binary GRS 1915+105 using spectral-timing analysis
Karan Akbari, Chintan Patel, Sayantan Bhattacharya +2
GRS 1915+105 is a black hole X-ray binary whose -class ("heartbeat") oscillations (50--100 s) are attributed to radiation-pressure instabilities in the inner accretion dis…
Circumstellar Disc and X-ray Variability in the Be/X-ray Binary SXP 5.05 During its 2024 Outburst
Chintan Patel, Sayantan Bhattacharya, Karan Akbari +3
Be/X-ray binaries provide a unique opportunity to study the interaction between neutron stars and circumstellar discs. SXP 5.05 is a particularly rare system, exhibiting eclipse-li…
A continuous transition from Type-C Quasi Periodic Oscillations to the Heartbeat state in the Black hole X-ray binary 4U 1630-47
Chintan Patel, Sayantan Bhattacharya, Karan Akbari +2
We present a timing analysis of the black hole X-ray binary (BHXRB) 4U 1630-47 using AstroSat observations from 10-19 March 2023, for the first time capturing a rare and rapid tran…