201 citations · 1.1k across the 35 of their papers we have counts for
35 papers
From Choked to Successful: The Role of Black Hole Spin in Collapsar Jet Breakout
Rushikesh Sonawane, Krishna Kumar, Shabnam Iyyani
Long gamma-ray bursts (LGRBs) are believed to originate from the core collapse of massive Wolf-Rayet (WR) stars, leading to the formation of a spinning black hole that powers a rel…
- Correlation in Time Resolved GRB Spectra: A Bottom-Up Approach with Optically Thin Inverse Compton Scattering Model
Pragyan Pratim Bordoloi, Ayush Shivkumar, Shabnam Iyyani
Gamma-ray bursts (GRBs) are the brightest explosions in the Universe, yet the origin of their emission remains uncertain. Time-resolved spectral analysis offers key insights into t…
Episode-wise spectro-polarimetry of GRB 220107A: Testing the hypothesis of evolving radiation mechanisms
Rahul Gupta, Rushikesh Sonawane, Shabnam Iyyani +17
We investigate the spectro-polarimetric properties of the long-duration GRB~220107A, which exhibited two distinct emission episodes separated by a 40 s quiescent gap, to test wheth…
Fastest or Significant: A Systematic Framework for Validating Global Minimum Variability Timescale Measurements of Gamma-ray Bursts
S. Bala, P. Veres, A. Goldstein +3
The minimum variability timescale (MVT) is a key observable used to probe the central engines of Gamma-Ray Bursts (GRBs) by constraining the emission region size and the outflow Lo…
From Empirical to Physical Model: Direct Fits of Optically Thin Inverse Compton Scattering to Prompt GRB Spectra
Pragyan Pratim Bordoloi, Shubh Mittal, Shabnam Iyyani
Gamma-ray burst (GRB) prompt emission is commonly attributed to non-thermal radiation processes operating in the optically thin regions of a relativistic outflow. Among these, opti…
Multivariate Time Series Classification of Fermi-Detected Gamma-Ray Transients Using Convolutional-Recurrent Neural Networks
Arpan Aryam John, Krushna Govind Shete, Shabnam Iyyani +1
Fermi Gamma-ray Space Telescope has detected a diverse range of gamma-ray transients since its launch in 2008. Over the years, Fermi has accumulated an extensive public archive of…
Deciphering the Physical Origin of GRB 240825A: A Long GRB Lacking a Bright Supernova
Rahul Gupta, Judith L. Racusin, R. Sanchez-Ramirez +54
We present a comprehensive multiwavelength analysis of GRB 240825A, a bright gamma-ray burst (GRB) detected by Fermi and Swift, with a prompt duration ( 4 sec in…
Spectro-polarimetry of GRB 180427A: evidence for distinct emission sites with varying polarisation
Rushikesh Sonawane, Shabnam Iyyani, Soumya Gupta +5
The dynamics of the origin of gamma-ray emissions in gamma-ray bursts (GRBs) remains an enigma. Through a joint analysis of GRB 180427A, observed by the Fermi Gamma-ray Space Teles…
Extremely luminous optical afterglow of an energetic gamma-ray burst GRB 230204B
Rahul Gupta, Judith Racusin, Vladimir Lipunov +47
Robotic telescope networks play an important role in capturing early and bright optical afterglows, providing critical insights into the energetics and emission mechanisms of GRBs.…
Investigating Polarization characteristics of GRB200503A and GRB201009A
Divita Saraogi, Suman Bala, Jitendra Joshi +18
We present results of a comprehensive analysis of the polarization characteristics of GRB 200503A and GRB 201009A observed with the Cadmium Zinc Telluride Imager (CZTI) on board As…
Unified theory of negative and positive spectral lags in GRB prompt phase due to shear Comptonization from a structured jet
Mukesh Kumar Vyas, Asaf Pe'er, Shabnam Iyyani
Positive spectral lags are commonly observed in gamma-ray burst (GRB) prompt phase where soft photons lag behind hard ones in their spectral studies. Opposite to this pattern, a fr…
Identification and modelling of optically thin inverse Compton scattering in the prompt emission of GRB131014A
Pragyan Pratim Bordoloi, Shabnam Iyyani
The mechanism responsible for the prompt gamma-ray emission of a gamma-ray burst continues to remain an enigma. The detailed analysis of the spectrum of GRB 131014A observed by the…
A detailed time-resolved and energy-resolved spectro-polarimetric study of bright GRBs detected by AstroSat CZTI in its first year of operation
Rahul Gupta, S. B. Pandey, S. Gupta +11
The radiation mechanism underlying the prompt emission remains unresolved and can be resolved using a systematic and uniform time-resolved spectro-polarimetric study. In this paper…
Exploring Gamma-Ray Burst Diversity: Clustering analysis of emission characteristics of Fermi and BATSE detected GRBs
Nishil Mehta, Shabnam Iyyani
Gamma-ray bursts (GRBs) are commonly attributed to the demise of massive stars or the merger of binary compact objects. However, their varied emission characteristics strongly impl…
Statistical analysis of long GRBs' prompt emission and X-ray flares: multivariate clustering and correlations
Joseph Saji, Shabnam Iyyani, Kratika Mazde
The extensive observations done by the X-ray telescope onboard Neil Gehrels Swift observatory has revealed the presence of late time flares concurrent with the decaying afterglow e…
Science with the Daksha High Energy Transients Mission
Varun Bhalerao, Disha Sawant, Archana Pai +72
We present the science case for the proposed Daksha high energy transients mission. Daksha will comprise of two satellites covering the entire sky from 1~keV to ~MeV. The prima…
Hard X-ray polarization catalog for a 5-year sample of Gamma-Ray Bursts using AstroSat CZT-Imager
Tanmoy Chattopadhyay, Soumya Gupta, Shabnam Iyyani +16
Cadmium Zinc Telluride Imager (CZTI) aboard AstroSat has been regularly detecting Gamma-Ray Bursts (GRBs) since its launch in 2015. Its sensitivity to polarization measurements at…
Onset of particle acceleration during the prompt phase in gamma-ray bursts as revealed by synchrotron emission in GRB160821A
Felix Ryde, Shabnam Iyyani, Björn Ahlgren +4
The physical processes of the gamma-ray emission and particle acceleration during the prompt phase in GRBs are still unsettled. In order to perform an unambiguous physical modellin…
Probing into emission mechanisms of GRB 190530A using time-resolved spectra and polarization studies: Synchrotron Origin?
Rahul Gupta, S. Gupta, T. Chattopadhyay +47
Multi-pulsed GRB 190530A, detected by the GBM and LAT onboard \fermi, is the sixth most fluent GBM burst detected so far. This paper presents the timing, spectral, and polarimetric…
Discovery and confirmation of the shortest gamma ray burst from a collapsar
Tomas Ahumada, Leo P. Singer, Shreya Anand +54
Gamma-ray bursts (GRBs) are among the brightest and most energetic events in the universe. The duration and hardness distribution of GRBs has two clusters, now understood to reflec…
Sub-MeV spectroscopy with AstroSat-CZT Imager for Gamma Ray Bursts
Tanmoy Chattopadhyay, Soumya Gupta, Vidushi Sharma +10
Cadmium Zinc Telluride Imager (CZTI) onboard AstroSat has been a prolific Gamma-Ray Burst (GRB) monitor. While the 2-pixel Compton scattered events (100 - 300 keV) are used to extr…
Identifying Black Hole Central Engines in Gamma-Ray Bursts
Vidushi Sharma, Shabnam Iyyani, Dipankar Bhattacharya
The nature of the gamma-ray burst (GRB) central engine still remains an enigma. Entities widely believed to be capable of powering the extreme jets are magnetars and black holes. T…
Study of prompt emission of short gamma ray bursts using multi-color blackbody: a clue to the viewing angle
Shabnam Iyyani, Vidushi Sharma
The prompt emission of short gamma ray bursts (sGRBs) with known redshifts are analyzed using the model of multi-color blackbody which is interpreted as the emission from a non-dis…
Spectro-polarimetric analysis of prompt emission of GRB 160325A: jet with evolving environment of internal shocks
Vidushi Sharma, Shabnam Iyyani, Dipankar Bhattacharya +3
GRB 160325A is the only bright burst detected by AstroSat CZT Imager in its primary field of view to date. In this work, we present the spectral and polarimetric analysis of the pr…