Semi-empirical model atmospheres for the chromosphere of the sunspot penumbra and umbral flashes Souvik Bose, Vasco M. J. Henriques, Luc Rouppe van der Voort and Tiago M. D. Pereira A&A, 627 (2019) A46 Published online: 01 July 2019 DOI: 10.1051/0004-6361/201935289