Constraints on the black-hole charges of M87* and Sagittarius A* by changing rates of photon spheres can be relaxed

N Tsukamoto, R Kase - Physical Review D, 2024 - APS
The Event Horizon Telescope (EHT) Collaboration observed ring images called the
shadows of M87* and Sagittarius A*(Sgr A*), which are supermassive objects in M87 and …

Continuum emission from within the plunging region of black hole discs

A Mummery, A Ingram, S Davis… - Monthly Notices of the …, 2024 - academic.oup.com
The thermal continuum emission observed from accreting black holes across X-ray bands
has the potential to be leveraged as a powerful probe of the mass and spin of the central …

Plunging region emission in the X-ray binary MAXI J0637− 430

A Mummery, J Jiang, A Fabian - Monthly Notices of the Royal …, 2024 - academic.oup.com
On 2019 November 2, the black hole X-ray binary MAXI J0637− 430 went into outburst, at
the start of which it was observed in a thermal 'disc-dominated'state. High photon energy …

The three-dimensional structure of black hole accretion flows within the plunging region

A Mummery, JM Stone - Monthly Notices of the Royal …, 2024 - academic.oup.com
We analyse, using new analytical models and numerical general relativistic
magnetohydrodynamic simulations, the three-dimensional properties of accretion flows …

Cost of excursions until first crossing of the origin for random walk and Lévy flights: An exact general formula

F Mori, SN Majumdar, P Vivo - Physical Review Research, 2024 - APS
We consider a discrete-time random walk on a line starting at x 0≥ 0 where a cost is
incurred at each jump. We obtain an exact analytical formula for the distribution of the total …

The stress at the ISCO of black-hole accretion discs is not a free parameter

JP Lasota, M Abramowicz - arxiv preprint arxiv:2410.06200, 2024 - arxiv.org
Radiation from the" plunging region"(the space between the innermost stable circular orbit
(ISCO) and the black-hole (BH) surface) of an accretion flow onto a BH is supposed to add a …

Cost of excursions until first return for random walks and L\'evy flights: an exact general formula

SN Majumdar, F Mori, P Vivo - arxiv preprint arxiv:2403.16152, 2024 - arxiv.org
We consider a discrete-time random walk where a cost is incurred at each jump. We obtain
an exact analytical formula for the distribution of the total cost of a trajectory until the process …