The influence of outflow and global magnetic field on the structure and spectrum of resistive CDAFs

Abstract

We examine the effects of a global magnetic field and outflow on radiatively inefficient accretion flow (RIAF) in the presence of magnetic resistivity. We find self-similar solutions for the height integrated equations that govern the behavior of the flow. We use the mixing length mechanism for studying the convection parameter. We adopt the radius dependent mass accretion rate $\dot{M}=\dot{M}_{\mathrm{out}}{(\frac{r}{r_{\mathrm{out}}})^{s}}$ , with $s> 0$ , to investigate the influence of outflow on the structure of inflow where $s$ is a constant and is an indication of the effect of the wind. Also, we have studied the radiation spectrum and temperature of convection dominated accretion flows (CDAFs). The thermal bremsstrahlung emission as a radiation mechanism is taken into account for calculating the spectra emitted by the CDAFs. The energy that powers bremsstrahlung emission at large radii is provided by convective transport from small radii and viscous and resistivity dissipation. Our results indicate that the disc rotates slower and accretes faster, it becomes hotter and thicker for a stronger wind. By increasing all components of the magnetic field, the disc rotates faster and accretes more slowly, while it becomes hotter and thicker. We show that the outflow parameter and all components of the magnetic field have the same effects on the luminosity of the disc. We compare the dynamical structure of the disc in two different solutions (with and without resistivity parameter). We show that only the radial infall velocity and the surface density could be changed by the resistivity parameter obviously. Increasing the effect of the wind increases the disc’s temperature and the luminosity of the disc. The effect of the magnetic field is similar to the effect of the wind on the disc’s temperature and the luminosity of the disc, but the influence of the resistivity on the observational properties is not evident.