[Okc-wp4] EO meeting this week on Thursday 24th

[Francesco Taddia]

Hi all,

two talks at the next EO meeting on Thursday 24th, 13:00, in the KTH meeting room (5th floor).
Here speakers, titles and abstracts:

1) Speaker: Magnus Axelsson

Title: Breaking the spectral degeneracies in black hole binaries with fast timing data

Abstract: The spectra of black hole binaries in the low/hard state are complex, with evidence for multiple different
 Comptonisation regions contributing to the hard X-rays, in addition to a cool disc component. However, it is difficult to
 constrain these components uniquely using spectral data alone. Using observations of Cygnus X-1, I will show that
 additional information from fast variability can break this degeneracy, and gives new insight into
 the physical processes active in the inner accretion flow.

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2) Speaker: Giovanni Camelio

Title: Disk formation from the collapse of a rotating neutron star

Abstract:
An unstable rotating neutron star can collapse to a black hole.
A particle in the Innermost Stable Circular Orbit (ISCO) of this black hole has
the lowest possible angular momentum that prevents it to fall into the black hole.
If the matter of the unstable neutron star has everywhere a specific angular
momentum smaller than that of the ISCO, no particle will escape the collapse.
Using this criterion, we estimate the mass of the disk that might form in a
neutron star collapse for a variety of Equation Of States (EOSs).
We find that for all considered EOSs the disk mass is too low to generate gamma
ray bursts with significant energy.
We checked our estimates with general relativistic dynamical simulations.


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cheers

/Francesco