Black holes at different flavours - WE - Heraeus - 2026 EAS Workshop for Early Career Research in Astronomy

Contribution List

62. Detectability of the eclipses of galactic nuclei by stars

Michal Zajaček (Masaryk University, Brno, Czech Republic)

Poster

We investigate the possibility of detecting stellar eclipses of millimeter radio cores in nearby radio-loud active galactic nuclei. At millimeter wavelengths, the compact radio core can be partially occulted by large evolved stars orbiting the central supermassive black hole within a dense nuclear star cluster. We show that stars with radii >= 500 Rsun can produce the eclipses with relative...

59. Magnetized Accretion Disk Around a Reissner–Nordström Naked Singularity

Maria Koper (Wydział Fizyki Uniwersytetu Warszawskiego)

Poster

We present magnetohydrodynamic simulations of a thin accretion disk around a Reissner–Nordström naked singularity, modeled with our pseudo-Newtonian potential. This potential accurately reproduces the orbital frequency, including the radius at which it reaches a maximum and eventually vanishes. The latter defines the zero-gravity sphere, below which the net force is repulsive. Our results show...

58. On the Origin of Asymmetric Inflow-Outflows Structures in Viscous Transonic Accretion Discs

Sanjit Debnath (Aryabhatta Research Institute of Observational Sciences (ARIES), India)

Poster

In transonic advective accretion flows, the presence of a shock gives rise to a hot, dense post-shock region that can act as the launching site of outflows. When viscosity is included, dissipation within this region increases the thermal energy of the flow, leading to a stronger pressure gradient that can drive more efficient mass ejection. The resulting outflows are not necessarily symmetric...

61. Probing frame-dragging effects in black hole binaries through LFQPO phase-resolved spectroscopy

Seshadri Majumder (Kyoto University)

Poster

Quasi-periodic oscillations (QPOs) are coherent X-ray timing features frequently observed in black hole X-ray binaries (BH-XRBs), originating from the innermost region of the accretion disc-corona system where general relativistic effects are expected to be in play. Among the proposed QPO models, the Lense-Thirring (LT) precession of the inner hot flow predicts a systematic modulation of the...

60. Quantum vortices in an accretion disk during the tidal stripping of a cold white dwarf

Dr Marek Nikołajuk (University of Białystok, Faculty of Physics)

Poster

We investigate the tidal stripping of a cold helium white dwarf (WD) by a stellar-mass black hole (BH). Due to the degenerate nature of the WD, we expect quantum effects to play a significant role in the dynamics. To capture these effects, we use a full quantum hydrodynamic framework to simulate the formation of the accretion disk. We model the WD as a Bose–Fermi droplet consisting of...

66. Radio AGNs in the era of large-scale sky surveys

Subhrata Dey (National Centre for Nuclear Research)

Poster

"In this talk, I will present results for 2,001 radio AGNs from the ROGUE I catalog (Kozieł-Wierzbowska et al. 2020), including Fanaroff-Riley type I, II, and hybrid I/II systems, as well as double-double, X-shaped, Z-shaped, wide-angle tail, narrow-angle tail, and head-tail radio galaxies. The sources span angular sizes from 5″ to 1,100″, corresponding to projected linear sizes of 10 kpc–2...

64. Warm corona

Agata Rozanska (CAMK PAN)

Poster

63. X- ray variability study of the NLS1 galaxy Ark 564

NIKITA S ARUN (Providence Women's College)

Poster

We present a broadband X-ray spectral study of the narrow-line Seyfert 1 galaxy Ark 564 using a long-term monitoring dataset obtained with the X-Ray Telescope (XRT) onboard Neil Gehrels Swift Observatory. Ark 564 is known for its strong X-ray variability and prominent soft X-ray excess, making it an excellent laboratory for investigating accretion processes. We analyze more than 70 Swift/XRT...

65. X-ray Spectral Evolution of the Changing-Look Blazar OQ 334

P. K. Navaneeth

Poster

The blazar B2 1420+32 (OQ 334, z = 0.682) has recently emerged as a primary laboratory for studying the "changing-look" (CL) phenomenon in jetted active galactic nuclei, characterized by transitions between FSRQ and BL Lac states. We present a detailed investigation into the complex nature of its X-ray emission using Swift-XRT observations spanning MJD 58095--60580. Using Bayesian Blocks...