Isotope shifts of the (3s3p)${}^3$P${}_{0,1,2}$ - (3s4s)${}^3$S${}_1$ Mg I transitions

We report measurements of the isotope shifts of the (3s3p)${}^3$P${}_{0,1,2}$ - (3s4s)${}^3$S${}_1$ Mg I transitions for the stable isotopes ${}^{24}$Mg (I=0), ${}^{25}$Mg (I=5/2) and ${}^{26}$Mg (I=0). Furthermore the ${}^{25}$Mg ${}^3$S${}_1$ hyperfine coefficient A(${}^3$S${}_1$) = (-321.6 $\pm$ 1.5) MHz is extracted and found to be in excellent agreement with state-of-the-art theoretical predictions giving A(${}^3$S${}_1$) = -325 MHz and B(${}^3$S${}_1$) $\simeq {10}^{-5}$ MHz. Compared to previous measurements, the data presented in this work is improved up to a factor of ten.