GRB 210121A: Observation of photospheric emissions from different regimes and the evolution of the outflow

Abstract

GRB 210121A was observed by Insight-HXMT, Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM), Fermi Gamma-ray Burst Monitor (Fermi/GBM) on Jan 21st 2021. In this work, photospheric emission from a structured jet is preferred to interpret the prompt emission phase of GRB 210121A and emissions from different regimes are observed on-axis. Particularly, the emission from the intermediate photosphere is first observed in the first 1.3 s of the prompt emission, while those from the other part are dominant by the saturated regime, and offers an alternative explanation compared with the previous work. Moreover, the emissions with considering the intermediate photosphere can well interpret the changes on low-energy photon index $\alpha$ during the pulses. Besides, the evolution of the outflow is extracted from time-resolved analysis, and a correlation of ${\Gamma }_0\propto L_0^{0.25\pm 0.05}$ is obtained, which implies that the jet may be mainly launched by neutrino annihilation in a hyper-accretion disk.

10 pages, 4 figures, published The ApJ, 931:112 (7pp), 2022 June 1

References in corpus (13)

• Neutrino-Cooled Accretion Disks around Spinning Black Hole
• Temporal Evolution Of Thermal Emission From Relativistically Expanding Plasma
• Neutrino-Dominated Accretion Models for Gamma-Ray Bursts: Effects of General Relativity and Neutrino Opacity
• Instabilities in the time-dependent neutrino disc in Gamma-Ray Bursts
• Magnetically Torqued Neutrino-Dominated Accretion Flows for Gamma-ray Bursts
• Low-energy Spectra of Gamma-ray Bursts from Cooling Electrons
• Propagation of a Short GRB Jet in the Ejecta: Jet Launching Delay Time, Jet Structure, and GW170817/GRB 170817A
• The HII Galaxy Hubble Diagram Strongly Favors $R_{\mathrm{h}}=ct$ over $\Lambda$CDM
• On Spectral Evolution and Temporal Binning in Gamma-Ray Bursts
• GRB 210121A: A Typical Fireball Burst Detected by Two Small Missions
• The First Insight-HXMT Gamma-Ray Burst Catalog: The First Four Years
• The Photosphere Emission Spectrum of Hybrid Relativistic Outflow for Gamma-ray Bursts
• The Hardness-intensity Correlation of Photospheric Emission from a Structured Jet for Gamma-Ray Bursts

Cited by in corpus (4)

• GECAM Localization of High Energy Transients and the Systematic Error
• The Origin of the Photospheric Emission of GRB 220426A
• Spectral and Jet Properties of the Quasi-thermal Dominated GRB 210121A, GRB 210610B and GRB 221022B
• Constraints from Gamma-ray Burst Phenomenology on the Hypothesis of Quark Star as the central engines of Gamma-ray Bursts