Freddi: Fast Rise Exponential Decay accretion Disk model Implementation
Abstract
Freddi (Fast Rise Exponential Decay: accretion Disk model Implementation) solves 1D evolution equations of the ShakuraSunyaev accretion disk. It simulates fast rise exponential decay (FRED) light curves of low mass Xray binaries (LMXBs). The basic equation of the viscous evolution relates the surface density and viscous stresses and is of diffusion type; evolution of the accretion rate can be found on solving the equation. The distribution of viscous stresses defines the emission from the source. The standard model for the accretion disk is implied; the inner boundary of the disk is at the ISCO or can be explicitely set. The boundary conditions in the disk are the zero stress at the inner boundary and the zero accretion rate at the outer boundary. The conditions are suitable during the outbursts in Xray binary transients with black holes. In a binary system, the accretion disk is radially confined. In Freddi, the outer radius of the disk can be set explicitely or calculated as the position of the tidal truncation radius.
 Publication:

Astrophysics Source Code Library
 Pub Date:
 October 2016
 Bibcode:
 2016ascl.soft10014M
 Keywords:

 Software