MESA Inlists and the final models of collapsing stars from paper "Exploring Origin of Ultra-Long Gamma-ray Bursts: Lessons from GRB 221009A"

To constrain the physical properties of ULGRB progenitors, we employ MESA to simulate the evolution of low-metallicity massive stars with different initial rotations. Utilizing the simulation parameters of the models at the stage of the onset of core collapse, we estimate the free fall timescales.  The estimation of free fall time is important to gain insights into how long the central engine can be fueled; thus, it can be compared with the T90 duration of the GRBs.The outcomes suggest that rotating massive stars could potentially be the progenitors of ULGRBs within the limits of the considered parameters and initial inputs to MESA in our models.