| Name: Amit Kumar |
| Affiliation: Indian institute of technology, Guwahati |
| Conference ID: ASI2026_618 |
| Title: Study of Neutrino dominated accretion flows (NDAF) around rotating black hole (BH) |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Amit Kumar(Indian Institute of technology, Guwahati), Sayan Chakrabarti(Indian Institute of technology, Guwahati), Santabrata Das(Indian Institute of technology, Guwahati) |
| Abstract: We investigate the physical properties of the central engine powering gamma-ray bursts (GRBs), modelled as a stellar-mass rotating black hole accreting through a neutrino-dominated accretion flow (NDAF) at hyper-accretion rates ($\dot{M}\sim 0.001$–$10\,M_\odot\,\mathrm{s^{-1}}$). At such high accretion rates, the disk becomes geometrically and optically thick, inhibiting photon escape, while neutrinos can efficiently escape and cool the flow through radiative emission and annihilation processes. By self-consistently solving the governing hydrodynamic equations, we obtain global transonic NDAF solutions featuring shock transitions and explore them over a wide range of black hole mass ($M_{\rm BH}$), spin ($a_{\rm k}$), and accretion rate. Using these shocked solutions, we estimate the neutrino luminosity ($L_\nu$) and neutrino annihilation luminosity ($L_{\nu\bar{\nu}}$) for both weakly ($a_{\rm k}=0$) and rapidly ($a_{\rm k}=0.99$) rotating black holes, finding good agreement between $L_{\nu\bar{\nu}}$ and the observed energy output of GRBs. Incorporating inputs from numerical simulations of binary neutron star and black hole–neutron star mergers, we further estimate the remnant black hole mass and spin parameters for the predicted range of post-merger disk mass ($M_{\rm disk}$). Our results show that shocked NDAFs can naturally reproduce the observed diversity in GRB energetics, with short GRB luminosities achievable either by low-mass, slowly spinning black holes or by more massive black holes with higher spins. We also identify a robust correlation in which $M_{\rm disk}$ decreases with increasing $a_{\rm k}$, remaining largely insensitive to $M_{\rm BH}$, supporting neutrino-dominated shocked accretion as a viable mechanism for powering GRB central engines. |
