Characterizations of generalized Robertson-Walker spacetimes concerning gradient solitons

In this article, we examine gradient type Ricci solitons and $(m,\tau )$-quasi Einstein solitons in generalized Robertson-Walker ($GRW$) spacetimes. Besides, we demonstrate that in this scenario the $GRW$ spacetime presents the Robertson-Walker ($RW$) spacetime and the perfect fluid ($PF$) spacetime presents the phantom era. Consequently, we show that if a $GRW$ spacetime permits a gradient $\tau$- Einstein solitons, then it also represents a $PF$ spacetime under certain condition.