X-ray outburst of 4U 0115+634 and ROTSE observations of its optical counterpart V635 Cas A. Baykal, Ü. Kızıloǧlu, N. Kızıloǧlu, Ş. Balman and S. Ç. İnam A&A, 439 3 (2005) 1131-1134 Published online: 12 August 2005 DOI: 10.1051/0004-6361:20052968