Second ROSAT all-sky survey (2RXS) source catalogue Th. Boller, M. J. Freyberg, J. Trümper, F. Haberl, W. Voges and K. Nandra A&A, 588 (2016) A103 Published online: 24 March 2016 DOI: 10.1051/0004-6361/201525648