Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane A. L. F. de Barros, V. Bordalo, E. Seperuelo Duarte, E. F da Silveira, A. Domaracka, H. Rothard and P. Boduch A&A, 531 (2011) A160 Published online: 06 July 2011 DOI: 10.1051/0004-6361/201016021