SN 2021wuf: A transitional type Ia supernova with a low-velocity gradient

In this paper, we present an extensive analysis of SN 2021 wuf, a transition between Ia-norm and SN 1991T-like supernovae, which exploded at the periphery of the tidal bridge between the pair galaxy NGC 6500 and NGC 6501, at a redshift of z = 0.01. Our observations, ranging from -21 to +276 days relative to the B-band maximum light, reveal that SN 2021wuf exhibits properties akin to normal SNe Ia, with a peak absolute magnitude of M_ max(B)$\ and a post-peak decline rate of $ m_ $(B)$\ The peak bolometric luminosity of this SN is estimated as $1.58\ $\,erg\,s^, corresponding to a 56Ni mass of $ M_ Ni The spectral features, including high-velocity Si romannumeral2 lambda 6355 lines, a plateau in the Si romannumeral2 lambda 6355 velocity evolution and the nickel-to-iron ratio in the nebular phase, suggest a potential pulsating delayed detonation mechanism. The absence of intermediate-mass elements in the early phase and the high photospheric temperature, as inferred from the line-strength ratio of Si\ romannumeral2 \,lambda 5972 to Si\ romannumeral2 \,lambda 6355 (named as R(Si romannumeral2 )), further support this classification.