*Article* **Progenitors of Long-Duration Gamma-ray Bursts**

**Arpita Roy**

Cosmology Research Group, Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy; arpita.roy@sns.it

**Abstract:** We review the current scenario of long-duration Gamma-ray burst (LGRB) progenitors, and in addition, present models of massive stars for a mass range of 10–150 M with ∆M = 10 M and rotation rate *v*/*v*crit = 0 to 0.6 with a velocity resolution ∆*v*/*v*crit = 0.1. We further discuss possible metallicity and rotation rate distribution from our models that might be preferable for the creation of successful LGRB candidates given the observed LGRB rates and their metallicity evolution. In the current understanding, LGRBs are associated with Type-Ic supernovae (SNe). To establish LGRB-SN correlation, we discuss three observational paths: (i) space-time coincidence, (ii) evidence from photometric light curves of LGRB afterglows and SN Type-Ic, (iii) spectroscopic study of both LGRB afterglow and SN. Superluminous SNe are also believed to have the same origin as LGRBs. Therefore, we discuss constraints on the progenitor parameters that can possibly dissociate these two events from a theoretical perspective. We further discuss the scenario of single star versus binary star as a more probable pathway to create LGRBs. Given the limited parameter space in the mass, mass ratio and separation between the two components in a binary, binary channel is less likely to create LGRBs to match the observed LGRB rate. Despite effectively-single massive stars are fewer in number compared to interacting binaries, their chemically homogeneous evolution (CHE) might be the major channel for LGRB production.

**Keywords:** Gamma-ray bursts; massive stars; supernova; spectroscopy; binary stars; metallicity; rotation rate
