Triggered massive star formation associated with the bubble Hii region Sh2-39 (N5) N. U. Duronea, C. E. Cappa, L. Bronfman, J. Borissova, M. Gromadzki and M. A. Kuhn A&A, 606 (2017) A8 Published online: 22 September 2017 DOI: 10.1051/0004-6361/201730528