학술논문
Multi-wavelength study of the luminous GRB 210619B observed with Fermi and ASIM
Document Type
Working Paper
Author
Caballero-García, M. D.; Gupta, Rahul; Pandey, S. B.; Oates, S. R.; Marisaldi, M.; Ramsli, A.; Hu, Y. -D.; Castro-Tirado, A. J.; Sánchez-Ramírez, R.; Connell, P. H.; Christiansen, F.; Ror, A. Kumar; Aryan, A.; Bai, J. -M.; Castro-Tirado, M. A.; Fan, Y. -F.; Fernández-García, E.; Kumar, A.; Lindanger, A.; Mezentsev, A.; Navarro-González, J.; Neubert, T.; Østgaard, N.; Pérez-García, I.; Reglero, V.; Sarria, D.; Sun, T. R.; Xiong, D. -R.; Yang, J.; Yang, Y. -H.; Zhang, B. -B.
Source
Subject
Language
Abstract
We report on detailed multi-wavelength observations and analysis of the very bright and long GRB 210619B, detected by the Atmosphere-Space Interactions Monitor (ASIM) installed on the International Space Station (ISS) and the Gamma-ray Burst Monitor (GBM) on-board the Fermi mission. Our main goal is to understand the radiation mechanisms and jet composition of GRB 210619B. With a measured redshift of $z$ = 1.937, we find that GRB 210619B falls within the 10 most luminous bursts observed by Fermi so far. The energy-resolved prompt emission light curve of GRB 210619B exhibits an extremely bright hard emission pulse followed by softer/longer emission pulses. The low-energy photon indices ($\alpha_{\rm pt}$) values obtained using the time-resolved spectral analysis of the burst suggest a transition between the thermal (during harder pulse) to non-thermal (during softer pulse) outflow. We examine the correlation between spectral parameters and find that both peak energy and $\alpha_{\rm pt}$ exhibit the flux tracking pattern. The late time broadband photometric dataset can be explained within the framework of the external forward shock model with $\nu_m$ $< \nu_c$ $< \nu_{x}$ (where $\nu_m$, $\nu_c$, and $\nu_{x}$ are the synchrotron peak, cooling-break, and X-ray frequencies, respectively) spectral regime supporting a rarely observed hard electron energy index ($p<$ 2). We find moderate values of host extinction of E(B-V) = 0.14 $\pm$ 0.01 mag for the Small Magellanic Cloud (SMC) extinction law. In addition, we also report late-time optical observations with the 10.4 m GTC placing deep upper limits for the host galaxy ($z$=1.937), favouring a faint, dwarf host for the burst.
Comment: 24 pages, 18 figures, 10 tables, accepted for publication in MNRAS
Comment: 24 pages, 18 figures, 10 tables, accepted for publication in MNRAS