X-ray flaring from the young stars in Cygnus OB2 J. F. Albacete Colombo, M. Caramazza, E. Flaccomio, G. Micela and S. Sciortino A&A, 474 2 (2007) 495-504 Published online: 28 August 2007 DOI: 10.1051/0004-6361:20078064