  Following quenches from random initial configurations to zero temperature, we
study aging during evolution of the ferromagnetic (nonconserved) Ising model
towards equilibrium, via Monte Carlo simulations of very large systems, in
space dimensions $d=2$ and $3$. Results for the two-time autocorrelations,
obtained by using different acceptance probabilities for the spin-flip trial
moves, are in agreement with each other. We demonstrate the scaling of this
quantity with respect to $\ell/\ell_w$, where $\ell$ and $\ell_w$ are the
average domain sizes at $t$ and $t_w$ $(\leqslant t)$, the observation and
waiting times, respectively. The scaling functions are shown to be of power-law
type for $\ell/\ell_{w} \rightarrow \infty$. The exponents of these power-laws
have been estimated via the finite-size scaling analyses and discussed with
reference to the available results from non-zero temperatures. While in $d=2$
we do not observe any temperature dependence, in the case of $d=3$ the outcome
for quench to zero temperature is very different from the available results for
high temperature and violates a lower bound, which we explain via structural
consideration. We also present results on the freezing phenomena that this
model exhibits at zero temperature. Furthermore, from simulations of extremely
large system, thereby avoiding the freezing effect, it has been confirmed that
the growth of average domain size in $d=3$, that remained a puzzle in the
literature, follows the Lifshitz-Allen-Cahn law in the asymptotic limit.
