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Classical novae are expected to contribute to the 1809-keV Galactic $gamma$-ray emission by producing its precursor $^{26}$Al, but the yield depends on the thermonuclear rate of the unmeasured $^{25}$Al($p,gamma$)$^{26}$Si reaction. Using the $beta$ decay of $^{26}$P to populate the key $J^{pi}=3^+$ resonance in this reaction, we report the first evidence for the observation of its exit channel via a $1741.6 pm 0.6 (textrm{stat}) pm 0.3 (textrm{syst})$ keV primary $gamma$ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured $gamma$-ray energy and intensity with other experimental data on $^{26}$Si, we find the center-of-mass energy and strength of the resonance to be $E_r = 414.9 pm 0.6(textrm{stat}) pm 0.3 (textrm{syst}) pm 0.6(textrm{lit.})$ keV and $omegagamma = 23 pm 6 (textrm{stat})^{+11}_{-10}(textrm{lit.})$ meV, respectively, where the last uncertainties are from adopted literature data. We use hydrodynamic nova simulations to model $^{26}$Al production showing that these measurements effectively eliminate the dominant experimental nuclear-physics uncertainty and we estimate that novae may contribute up to 30% of the Galactic $^{26}$Al.
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 dom
$beta$ decay of $^{26}$P was used to populate the astrophysically important $E_x=$5929.4(8) keV $J^{pi}=3{^+}$ state of $^{26}$Si. Both $beta$-delayed proton at 418(8) keV and gamma ray at 1742(2) keV emitted from this state were measured simultaneou
The $beta$-decay properties of the neutron-deficient nuclei $^{25}$Si and $^{26}$P have been investigated at the GANIL/LISE3 facility by means of charged-particle and $gamma$-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength
Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H-burning regions. In particular, low-energy nuclear resonances in the $^{25}$Mg(p,$gamma$)$^{26}$Al reaction affect the production of radioactive $^{26}$Al$^{
Context. The diffuse gamma-ray emission of $^{26}{rm Al}$ at 1.8 MeV reflects ongoing nucleosynthesis in the Milky Way, and traces massive-star feedback in the interstellar medium due to its 1 Myr radioactive lifetime. Interstellar-medium morphology