GRB 190114C: Fireball Energy Budget and Radiative Efficiency Revisited

Abstract

The jet composition of gamma-ray bursts (GRBs), as well as how efficiently the jet converts its energy to radiation, are long-standing problems in GRB physics. Here, we reported a comprehensive temporal and spectral analysis of the TeV-emitting bright GRB 190114C. Its high fluence ($\sim$ 4.4$\times$10${}^{-4}$ erg cm${}^{-2}$) allows us to conduct the time-resolved spectral analysis in great detail and study their variations down to a very short time-scale ($\sim$0.1 s) while preserving a high significance. Its prompt emission consists of three well-separated pulses. The first two main pulses ($P_1$ and $P_2$) exhibit independently strong thermal components, starting from the third pulse ($P_3$) and extending to the entire afterglow, the spectra are all nonthermal, the synchrotron plus Compton upscattering model well interprets the observation. By combining the thermal ($P_1$ and $P_2$) and the nonthermal ($P_3$) observations based on two different scenarios (global and pulse properties) and following the method described in Zhang et al., we measure the fireball parameters and GRB radiative efficiency with little uncertainties for this GRB. A relevantly high GRB radiative efficiency is obtained based on both the global and pulse properties, suggesting that if GRBs are powered by fireballs, the efficiency can sometimes be high. More interestingly, though the observed parameters are individually different (e.g., the amount of mass loading $M$), the radiative efficiency obtained from $P_1$ (${\eta }_{\gamma }=36.0\pm 6.5\%$) and $P_2$ (${\eta }_{\gamma }=41.1\pm 1.9\%$) is roughly the same, which implies that the central engine of the same GRB has some common properties.

18 pages, 3 figures, 2 tables, accepted for publication in The Astrophysical Journal

References in corpus (15)

• Array Programming with NumPy
• The NumPy array: a structure for efficient numerical computation
• Teraelectronvolt emission from the $\gamma$-ray burst GRB 190114C
• GRB Radiative Efficiencies Derived from the Swift Data: GRBs vs. XRFs, Long vs. Short
• A new method of determining the initial size and Lorentz factor of gamma-ray burst fireballs using a thermal emission component
• Multiwavelength analysis of the intriguing GRB 061126: the reverse shock scenario and magnetization
• The Onset of Gamma-Ray Burst Afterglow
• Towards a Better Understanding of the GRB Phenomenon: a New Model for GRB Prompt Emission and its effects on the New Non-Thermal L${}_{\mathrm{i}}^{\mathrm{NT}}$-E${}_{\mathrm{peak},\mathrm{i}}^{\mathrm{rest},\mathrm{NT}}$ relation
• GRB 190114C: from prompt to afterglow?
• Synchrotron Self-inverse Compton Radiation From Reverse-shock on GRB120326A
• Dissecting the Energy Budget of a Gamma-Ray Burst Fireball
• A Cosmological Fireball with Sixteen-Percent Gamma-Ray Radiative Efficiency
• Standard GRB Spectral Models "Misused"?
• Revisiting the Spectral-Energy Correlations of GRBs with {\it Fermi} Data I: Model-wise Properties
• Gravo-thermal catastrophe in gravitational collapse and energy progenitor of Gamma-Ray Bursts