Mass of the active galactic nucleus black hole XMMUJ134736.6+173403 K. Goluchová, G. Török, E. Šrámková, M. A. Abramowicz, Z. Stuchlík and J. Horák A&A, 622 (2019) L8 Published online: 31 January 2019 DOI: 10.1051/0004-6361/201834774