Supernovae at distances < 40 Mpc:. II. Supernova rate in the local Universe

This is the second paper of a series aiming to determine the birth rates of supernovae (SNe) in the local Universe. We aimed to estimate the SN rates in the local Universe and fit the delay-time distribution of type Ia SNe (SNe Ia) to put constraints on their progenitor scenarios. We performed a Monte Carlo simulation to estimate volumetric rates using the nearby SN sample introduced in Paper I. The rate evolution of core-collapse (CC) SNe closely follows the evolution of the cosmic star formation history, while the rate evolution of SNe Ia involves the convolution of the cosmic star formation history and a two-component delay-time distribution including a power law and a Gaussian component. The volumetric rates of type Ia, Ibc, and II SNe are derived as $0.325±0.040^ $, $0.160±0.028^ $, and $0.528±0.051^ $ (in units of $10^ yr^ Mpc^ h^3_ $), respectively. The rate of CCSNe ($0.688±0.078^ $) is consistent with previous estimates, which trace the star formation history. Conversely, the newly derived local SN Ia rate is larger than existing results given at redshifts 0.01 < z < 0.1, favoring an increased rate from the Universe at z ∼ 0.1 to the local Universe at z $<$ 0.01. A two-component model effectively reproduces the rate variation, with the power law component accounting for the rate evolution at larger redshifts and the Gaussian component with a delay time of 12.63±0.38 Gyr accounting for the local rate evolution. This delayed component, with its exceptionally long delay time, suggests that the progenitors of these SNe Ia were formed around 1 Gyr after the birth of the Universe, which could only be explained by a double-degenerate progenitor scenario. Comparison with the Palomar Transient Factory (PTF) sample of SNe Ia at z = 0.073 and the morphology of their host galaxies, reveals that the increased SN Ia rate at z $<$ 0.01 is primarily due to the SNe Ia of massive E and S0 galaxies with old stellar populations. Based on the above results, we estimate the Galactic SN rate as 3.08±1.29 per century.