Caballero, I.Pottschmidt, K.Barragan, L.Ferrigno, C.Kretschmar, P.Suchy, S.Wilms, J.Santangelo, A.Kreykenbohm, I.Rothschild, R.Klochkov, D.Staubert, R.Finger, M.H.Camero-Arranz, A.Makishima, K.Mihara, T.Nakajima, M.Enoto, T.Iwakiri, W.Terada, Y.2021-06-252021-06-252010-03-15Caballero, I. et al.; Peculiar outburst of A 0535+26 observed with INTEGRAL, RXTE and Suzaku; High Energy Astrophysical Phenomena, 15 March, 2010; https://arxiv.org/abs/1003.2969http://hdl.handle.net/11603/21830The Extreme sky: Sampling the Universe above 10 keV - extremesky2009, October 13-17, 2009 Otranto (Lecce) ItalyA normal outburst of the Be/X-ray binary system A0535+26 has taken place in August 2009. It is the fourth in a series of normal outbursts that have occured around the periastron passage of the source, but is unusual by starting at an earlier orbital phase and by presenting a peculiar double-peaked light curve. A first "flare" (lasting about 9 days from MJD 55043 on) reached a flux of 440 mCrab. The flux then decreased to less than 220 mCrab, and increased again reaching 440 mCrab around the periastron at MJD 55057. Target of Opportunity observations have been performed with INTEGRAL, RXTE and Suzaku. First results of these observations are presented, with special emphasis on the cyclotron lines present in the X-ray spectrum of the source, as well as in the pulse period and energy dependent pulse profiles of the source.6 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)Text