| Authors : | Soumya Gupta, Rahul Gupta, Tanmoy Chattopadhyay, Dipankar Bhattacharya, A.R. Rao
Sunder Sahayanathan, Santosh Vadawale, Varun Bhalerao, Gulab Devangan, Navaneeth PK |
| Authors Affiliation: | Soumya Gupta, Sunder Sahayanathan (Bhabha Atomic Research Center, Mumbai, Maharashtra-400094, India, Homi Bhabha National Institute, Mumbai, Maharashtra-400094, India)
Rahul Gupta (Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263002, India, Department of Physics, Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur-273009, India)
Tanmoy Chattopadhyay (Kavli Institute of Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305, USA)
Dipankar Bhattacharya (Department of Physics, Ashoka University Rai, Sonipat, Haryana-131029, India)
A.R. Rao (Tata Institute of Fundamental Research, Mumbai, Maharashtra-400005, India)
Santosh Vadawale (Physical Research Laboratory Thaltej, Ahmedabad, Gujarat 380009, India)
Varun Bhalerao (Indian Institute of Technology Bombay Powai, Mumbai, Maharashtra 400076, India)
Gulab Devangan, Navaneeth PK (Inter-University Center for Astronomy and Astrophysics Pune, Maharashtra-411007, India) |
| Abstract : | GRB 230307A is the second-most brightest long burst found associated with Kilonova emission, providing a unique opportunity to explore the open question on radiation mechanism and jet composition of Gamma-ray bursts (GRBs). In this paper, we examine the temporal, spectral and polarimetric characteristics of the high-energy radiation emitted by GRB 230307A based on prompt emission spectro-polarimetric analysis using joint AstroSat Cadmium Zinc Telluride Imager (CZTI) and Fermi observations. We performed a detailed time-averaged and time-resolved spectro-polarimetric analysis of GRB 230307A and found evidence of the transition from Baryonic to Poynting flux-dominated jet composition within the burst’s duration. The detection of such evolution in spectro-polarimetric properties of a GRB originating from a merger offers new possibilities for characterizing the progenitor’s nature. Additionally, we compared the high-energy properties of GRB 230307A with GRB 211211A and noted that both of these nearby long-Kilonovae-connected bursts have similar temporal morphology, i.e., a hard spike followed by softer emission |
