Accretion Disks in Dyonic Dilatonic Black Hole Spacetimes

We examine the properties of thin accretion disks in non-extremal, dyonic-like, dilatonic charged black hole spacetimes. In the most general case, the solution is characterized by three physical quantities: a dimensionless parameter a , which is explicitly defined as a function of the dilatonic coupling vectors, and the parameters μ and P , which are related to the total gravitational mass and net charge of the source, respectively. We also derive solutions for timelike circular geodesics and apply them to analyze the characteristics of thin accretion disks. To this end, we compute the orbital parameters of test particles in the equatorial plane for circular orbits, such as the angular velocity, specific energy, and specific angular momentum. In addition, for selected values of a , we consider a simple model for the disk’s radiative flux, differential luminosity, and spectral luminosity, employing the well-known Novikov-Page-Thorne formalism. We investigate the possibility of distinguishing Schwarzschild and Reissner-Nordström black holes from dilatonic dyonic black holes through their accretion disk properties. Unlike previous studies, all analyses here are explicitly performed in terms of the total gravitational mass M and net charge Q of the source. The potential astrophysical implications of the obtained results are also discussed.