Swift J164449.3+573451 event: generation in the collapsing star cluster?

TL;DR

This paper proposes a model where the unique gamma-ray event Swift J164449.3+573451 results from a collapsing galactic nucleus involving stellar remnants, leading to various energetic phenomena.

Contribution

It introduces a new scenario linking galactic nucleus collapse with gamma-ray bursts and multi-band emissions, expanding understanding of such cosmic events.

Findings

Neutron star and black hole collisions can produce short GRBs.

Multiple peaks in the event may result from matter accretion and gravitational lensing.

Galactic nucleus collapse can generate observable high-energy phenomena.

Abstract

We discuss the multiband energy release in a model of a collapsing galactic nucleus, and we try to interpret the unique super-long cosmic gamma-ray event Swift J164449.3+573451 (GRB 110328A by early classification) in this scenario. Neutron stars and stellar-mass black holes can form evolutionary a compact self-gravitating subsystem in the galactic center. Collisions and merges of these stellar remnants during an avalanche contraction and collapse of the cluster core can produce powerful events in different bands due to several mechanisms. Collisions of neutron stars and stellar-mass black holes can generate gamma-ray bursts (GRBs) similar to the ordinary models of short GRB origin. The bright peaks during the first two days may also be a consequence of multiple matter supply (due to matter release in the collisions) and accretion onto the forming supermassive black hole. Numerous smaller peaks and later quasi-steady radiation can arise from gravitational lensing, late accretion of gas onto the supermassive black hole, and from particle acceleration by shock waves. Even if this model will not reproduce exactly all the Swift J164449.3+573451 properties in future observations, such collapses of galactic nuclei can be available for detection in other events.