VLBA SiO maser observations of the OH/IR star OH 44.8-2.3: magnetic field and morphology N. Amiri, W. H. T. Vlemmings, A. J. Kemball and H. J. van Langevelde A&A, 538 (2012) A136 Published online: 14 February 2012 DOI: 10.1051/0004-6361/201117452