Astrophysics

hedis

hedis is a code, formerly writtin in Fortran 90/95, aimed at simulating accreting processes, based on works of Duschl & Strittmatter1. The main purpose is the balancing of black hole masses and the mass fluxes towards the black hole.

First, for the one-dimensional modeling only the radial dimension was resolved. The azimuthal dimension was thereby assumed to be symmetric and the height-dimension derived from other quantities. In conjunction with the implicit time integration method these assumptions lead to extremely short computation times. This enables, e.g., the creation of catalogues of quasar-populations. Additonally, it can be used in sub-grids of large-box simulations2. A possible application would be for example early accretion processes in large scale simulations during reionization.

Today, hedis 2.0 has been developed and is based on arbitrary curvilinear-orthogonal coordinates. There is indeed still a spatial symmetry in azimuthal direction, however, the angular momentum is conserved. This leads to a system of three conservation equations for mass, radial momentum and angular momentum, which is numerically solved. The program is structured modularely, which simplifies possible extensions without influencing the generic modules3. Furthermore, this enables a wide spectrum of test cases which verify the proficiency of the code.

Please send any requests to

T. Breslein

S. Deschner

 

Ref.:

1 Duschl and Strittmatter ADS, 2011

2 Blank and Duschl ADS, 2016

3 Illenseer and Duschl ADS, 2015