Modified viscosity paper accepted

The article on “Modified viscosity in accretion disks. Application to Galactic black hole binaries, intermediate mass black holes, and AGN” has been accepted for publication in Astronomy and Astrophysics. The authors are Mikołaj Grzędzielski, Agnieszka Janiuk, Bożena Czerny and Quingwen Wu, and the content of this article will provide a contribution to Mikolaj’s PhD thesis. The term ‘modified viscosity’ is used in this paper in the context of the generalized prescription for the viscous stress tensor, on which we base our numerical simulations of accretion disks. This prescription is accounting for a variable contribution of the gas, with respect to radiation, pressure in the energy dissipation, and the scaling parameter is denoted with a Greek symbol “mu. Figure below shows how the scaling relations work for accreting black holes across the many orders of magnitude in their mass, and thus related timescales and luminosities. Full text of the paper can be found here.



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ICM Session

On 19-21 April, we attended the Users session of the Interdisciplinary Center for Modeling. The event was organized at the Main Library of the Warsaw University, and gathered scientists who run their numerical simulations on the ICM supercomupters. Our group was represented by Agnieszka Janiuk and Kostas Sapountzis, who presented the results and numerical tests of the HARM-MP code that we use to simulate engines of gamma ray bursts. Moreover, Petra Sukova prepared a poster to show the preliminary results of her studies on the shocks in slowly rotating accretion flows in the centers of weakly active galaxies. Website with the session programme and sponsors list is here.


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New CompStar

On March 27-31, in Warsaw we held the annual meeting of the New CompStar Action. Agnieszka Janiuk participated there to show her most recent results on the microphysics in the GRB central engine and numerical modeling. Meeting was hosted in the Staszic Palace, the main building of the Polish Academy of Sciences, located in the Warsaw Old Town. The webpage of the conference is here.


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