****


    Index
    Curriculum Vitae
    Publications
   
   Presentations

   Students

    Journal Club
   
   Delta

   

Contact

    E-mail

    Po polsku

Talk at the XMM Conference, Granada, May 2008 "Accretion in the Collapsar. How Long Can be a Long GRB? "



• The Nature of the Intranight Variability of Radio-Quiet Quasars

Poster from the XMM Conference in 2008.


• Hydrodynamical Simulations of the AGN Central Engine in 3D

Poster from the XMM Conference in 2008.


• Formation and evolution of a torus in 3D

Movie 1...

The movie shows the formation of a 3D toroidal structure around the accreting black hole (purely hydrodynamic case). After initial stage of a purely spherical, Bondi accretion, the rotationally supported torus is formed. The isosurfaces shown by 3 different colors denote the constant density regions (in cgs units). In the innermost regions, the velocity of the gas is supersonic, and instabilities arise. Finally, the structure gets tilted with respect to the equator, and starts precessing.

    Movie 2...

The movie shows the case of the case of non-axisymmetric initial conditions: the rotating gas is present not at every azimuth around the black hole, but only in the region limited to delta(phi)=120o, and the closed, rotationally supported torus does not form.


    Movie 3...

The same as above but for the initial condition of delta(phi)=240o. The torus does not form and the flow behaves chaotically.



    Movie 4...

The same as above but for the initial condition of delta(phi)=330o. In this case the torus forms, nevertheless it is unstable and precesses.



    Movie 5...

The isosurfaces of constant specific (i.e. per unit mass) angular momentum (in units of the critical angular momentum, lc= 2 Rgc). The simulation is made for the axisymmetric initial conditions (the same as in Movie 1).


    Movie 6...

The isosurfaces of constant specific angular momentum. The simulation is made for the non-axisymmetric initial conditions with delta(phi)=330o (as in Movie 4). The film shows how the material with low and high angular momentum is mixing.



   






Evolution of density and velocity field in the central region, as shown in the equatorial plane and azimuthal cuts at phi=0o and 180o (simulation for delta(phi)=330o; as in Movie 4).



Seminar "Black hole accretion with low angular momentum", CfA, 07/11/2007



• How long can be a gamma ray burst?

Poster from the Nuclear Astrophysics Conference, Pasadena, July 2007


• Instabilities in the hyperaccreting, neutrino-cooled disk in GRB

Poster from the Nuclear Astrophysics Conference, Pasadena, July 2007