  The rate of the $^{25}$Al($p$,$\gamma$)$^{26}$Si reaction is one of the few
key remaining nuclear uncertainties required for predicting the production of
the cosmic $\gamma$-ray emitter $^{26}$Al in explosive burning in novae. This
reaction rate is dominated by three key resonances ($J^{\pi}=0^{+}$, $1^{+}$
and $3^{+}$) in $^{26}$Si. Only the $3^{+}$ resonance strength has been
directly constrained by experiment. A high resolution measurement of the
$^{25}$Mg($d$,$p$) reaction was used to determine spectroscopic factors for
analog states in the mirror nucleus, $^{26}$Mg. A first spectroscopic factor
value is reported for the $0^{+}$ state at 6.256 MeV, and a strict upper limit
is set on the value for the $1^{+}$ state at 5.691 MeV, that is incompatible
with an earlier ($^{4}$He,$^{3}$He) study. These results are used to estimate
proton partial widths, and resonance strengths of analog states in $^{26}$Si
contributing to the $^{25}$Al($p$,$\gamma$)$^{26}$Si reaction rate in nova
burning conditions.
