On the X-ray, optical and radio afterglows of the BdHN I GRB 180720B generated by the synchrotron emission

Abstract

Gamma-ray bursts (GRBs) are systems of unprecedented complexity across all the electromagnetic spectrum, including the radio, optical, X-rays, gamma-rays in the megaelectronvolt (MeV) and gigaelectronvolt (GeV) regime, as well as ultrahigh-energy cosmic rays (UHECRs), each manifested in seven specific physical processes with widely different characteristic evolution timescales ranging from $10^{-14}$ s to $10^7$ s or longer. We here study the long GRB 180720B originating from a binary system composed of a massive carbon-oxygen (CO) star of about $10M_{\odot }$ and a companion neutron star (NS). The gravitational collapse of the CO star gives rise to a spinning newborn NS ($\nu$NS), with an initial period of $P_0=1$ ms that powers the synchrotron radiation in the radio, optical, and X-ray wavelengths. We here only investigate the GRB 180720B afterglows and present a detailed treatment of its origin based on the synchrotron radiation released by the interaction of the $\nu$NS and the SN ejecta. We show that in parallel to the X-ray afterglow, the spinning $\nu$NS also powers the optical and radio afterglows and allows us to infer the $\nu$NS and ejecta parameters that fit the observational data.

Accepted for publication in The Astrophysical Journal

References in corpus (11)

• A very-high-energy component deep in the Gamma-ray Burst afterglow
• Hypercritical Accretion, Induced Gravitational Collapse, and Binary-Driven Hypernovae
• Multipolar electromagnetic fields around neutron stars: exact vacuum solutions and related properties
• Radio Afterglows of Very High Energy Gamma-Ray Bursts 190829A and 180720B
• Gravitomagnetic interaction of a Kerr black hole with a magnetic field as the source of the jetted GeV radiation of gamma-ray bursts
• The Arcminute Microkelvin Imager Catalogue of Gamma-ray Burst afterglows at 15.7 GHz
• The morphology of the X-ray afterglows and of the jetted GeV emission in long GRBs
• Nature of the ultrarelativistic prompt emission phase of GRB 190114C
• The structure of the ultrarelativistic prompt emission phase and the properties of the black hole in GRB 180720B
• GRB 190829A -- A Showcase of Binary Late Evolution
• The white dwarf binary merger model of GRB 170817A

Cited by in corpus (2)

• GRB-SN Association within the Binary-Driven Hypernova Model
• Probing electromagnetic-gravitational wave emission coincidence in type I binary-driven hypernova family of long GRBs at very-high redshift