In-orbit background of X-ray microcalorimeters and its effects on observations S. Lotti, D. Cea, C. Macculi, T. Mineo, L. Natalucci, E. Perinati, L. Piro, M. Federici and B. Martino A&A, 569 (2014) A54 Published online: 23 September 2014 DOI: 10.1051/0004-6361/201323307