GRBs and Hypernova Explosions of Some Galactic Sources

TL;DR

This paper investigates the rotational energy of black holes in certain galactic sources, linking their properties to gamma-ray bursts and hypernova explosions, and highlights how donor star mass influences explosion energy and black hole spin.

Contribution

It provides a quantitative analysis connecting black hole Kerr parameters, donor star mass, and explosion energy, proposing a model for the evolution of these sources and their relation to GRBs and hypernovae.

Findings

Galactic sources are remnants of GRB and hypernova explosions with sufficient rotational energy.

Low donor mass leads to higher black hole spin and more energetic explosions.

Donor star mass influences the energy and nature of the explosion.

Abstract

Knowing the Kerr parameters we can make quantitative calculations of the rotational energy of black holes. We show that Nova Sco (GRO J1655 - 40), Il Lupi (4U 1543 - 47), XTE J1550 - 564 and GS 2023 + 338 are relics of gamma-ray burst (GRB) and Hypernova explosions. They had more than enough rotational energy to power themselves. In fact, they had so much energy that they would have disrupted the accretion disk of the black hole that powered them by the communicated rotational energy, so that the energy delivery was self limiting. The most important feature in producing high rotational energy in the binary is low donor (secondary star) mass. We suggest that V4641 Sgr (XTE J1819 - 254) and GRS 1915 + 105 underwent less energetic explosions; because of their large donor masses. These explosions were one or two orders of magnitude lower in energy than that of Nova Sco. Cyg X - 1 (1956 + 350) had an even less energetic explosion, because of an even larger donor mass. We find that in the evolution of the soft X-ray transient sources the donor (secondary star) is tidally locked with the helium star, which evolved from the giant, as the hydrogen envelope is stripped off in common envelope evolution. The tidal locking is transferred from the helium star to the black hole into which it falls. Depending on the mass of the donor, the black hole can be spun up to the angular momentum necessary to power the GRB and Hypernova explosion. The donor decouples, acting as a passive witness to the explosion which, for the given angular momentum, then proceeds as in the Woosley Collapsar model. High mass donors which tend to follow from low metallicity give long GRBs because their lower energy can be accepted by the central engine.