Constraining the jet parameters of gamma ray bursts (GRBs)

	Gamma Ray Bursts(GRBs) emit an extraordinary amount of radiation in a short duration and they originate from
 cosmological distances. A lot of work has been done on describing the spectral and timing properties of the GRBs, but
 not all of them are explained in a universal model. I will present an overview of the prompt to afterglow properties of GRBs
  and highlight that  the interface between the prompt and afterglow emission is less investigated and less understood. 
 An attempt is made to bridge  this gap  by making a detailed time resolved  spectroscopy of the prompt emission 
 and connecting their properties to the afterglows.
 We selected  a sample of GRBs which has 
overlap in the detectors working in the interface energy regimes and I will present the results. Making GRBs as a standard rulers 
of the distance in the universe is a long term goal of GRB Cosmology. Many 
correlations have been found and are too dispersive to firmly achieve this goal. A pulse-wise correlation has been shown to 
be tighter. We have analysed a suitable sample of 25 Fermi GRBs with more than 40 pulses to increase the significance of the 
correlation. For reducing the intrinsic spread of these correlation we are meticulously analysing the GRB pulses by taking the pulse
 shape, evolution of pulse spectral parameters into account. I will discuss here how the Astrosat CZTI data can improve upon or increase the significance of the results.
 Spectral and timing analysis of a first GRB observed by Astrosat is used for  cross calibration of the CZTI instrument. Finally, I will  discuss how
 various spectral components can be accommodated within the cannon ball model of GRBs: This model has been shown to be successfully describing many of the prompt and afterglow properties of the 
GRBs. This model predicts a SN should be associated to every GRB. As an exercise we scaled the 1998bw SN to find that for GRB160131A and predicted a SN should peak after 26 days 
 in R-band.