papers

Publications (6)

astro-ph.SR2025

Comprehensive UV and Optical spectral analysis of Cygnus X-1: Stellar and wind parameters, abundances, and evolutionary implications

V. Ramachandran, A. A. C. Sander, L. M. Oskinova +7

We present a comprehensive analysis of Cyg X-1, utilizing archival high-resolution UV and optical spectra in conjunction with sophisticated atmospheric models. Notably, this is the…

astro-ph.HE2025

Disentangling the stellar atmosphere and the focused wind in different accretion states of Cygnus X-1

M. Brigitte, P. Hadrava, B. Kubátová +8

In high-mass X-ray binaries (HMXBs), the compact object accretes the strong stellar wind of an O-B supergiant companion star. X-ray flux variations alter the stellar wind's ionizat…

astro-ph.HE2026

Optical outburst evolution of the transient black hole X-ray binary Swift J1727.8-1613: Disc response to jet ejections and late-outburst emergence of powerful disc winds

N. Castro Segura, K. Solomons, J. M. Corral-Santana +22

Swift J1727.81613 is a newly discovered transient low-mass X-ray binary harbouring a stellar-mass () black hole. We present state-resolved VLT/X-Shooter optical…

astro-ph.HE2025

X-ray polarization of accreting black holes: Cyg X-1 and Swift J1727.8-1613

M. Brigitte, J. Svoboda

The Imaging X-ray Polarimetry Explorer is an X-ray observatory measuring the X-ray polarization in the 2-8 keV energy range. Highly sensitive to the system's geometry, X-ray polari…

astro-ph.HE2025

Recovery of the X-ray polarisation of Swift J1727.81613 after the soft-to-hard spectral transition

J. Podgorný, J. Svoboda, M. Dovčiak +34

We report on the detection of X-ray polarisation in the black-hole X-ray binary Swift J1727.81613 during its dim hard spectral state by the Imaging X-ray Polarimetry Explorer (I…

astro-ph.HE2024

IXPE observation confirms a high spin in the accreting black hole 4U 1957+115

L. Marra, M. Brigitte, N. Rodriguez Cavero +113

We present the results of the first X-ray polarimetric observation of the low-mass X-ray binary 4U 1957+115, performed with the Imaging X-ray Polarimetry Explorer in May 2023. The…