Galactic interstellar sulfur isotopes: A radial ${}^{32}$S$/$${}^{34}$S gradient?

H. Z. Yu, J. S. Zhang, C. Henkel +9

We present observations of ${}^{12}$C${}^{32}$S, ${}^{12}$C${}^{34}$S, ${}^{13}$C${}^{32}$S and ${}^{12}$C${}^{33}$S J=2$-$1 lines toward a large sample of massive star forming regions by using th…