Electron-positron outflow from black holes

Area of Science:

• Astrophysics
• Black Hole Physics
• High-Energy Astronomy

Background:

• Cosmological gamma-ray bursts (GRBs) are the most luminous transient events observed.
• The central engine powering GRBs, potentially involving low-mass black holes, remains poorly understood.
• Black hole spin interacting with magnetic fields is a candidate mechanism for energy extraction.

Purpose of the Study:

• To investigate the role of black hole spin in generating outflows relevant to GRBs.
• To provide a theoretical framework connecting black hole properties to GRB emission characteristics.
• To propose a viable central engine model for GRB fireball simulations.

Main Methods:

• Theoretical modeling of charged particle behavior near a rotating black hole in an external magnetic field.
• Derivation of equations for outflow generation and emission based on black hole mass and spin.
• Calculation of normalized isotropic emission and half-opening angle.

Main Results:

• A rapidly rotating black hole produces outflow from electrostatic equilibrium.
• Normalized isotropic emission is estimated as approximately 10(48)(B/B(c))(2)(M/7M)(2)sin(2) theta erg/s.
• The half-opening angle of the outflow is constrained by theta >= sqrt[B(c)/3B].

Conclusions:

• Black hole spin in a magnetic field can generate outflows consistent with GRB requirements.
• The proposed outflow mechanism offers a potential input for GRB fireball models.
• This work advances the understanding of GRB central engines and their progenitors.