Seminar:"The scarcely known X-ray pulsar 4U 1909+07-An overlooked pearl"
The scarcely known X-ray pulsar 4U 1909+07 - an overlooked pearl
Speaker: Ingo Kreykenbohm, University of Erlangen, Germany
Abstract: After an introduction in general X-ray astronomy I will present an overview of X-ray binaries and accretion onto a compact object with special emphasis on accretion from the stellar wind. In the second
half of the talk, I will present a detailed spectral and temporal analysis of the accreting High Mass X-ray Binary (HMXB) pulsar 4U 1909+07 using INTEGRAL and RXTE data. The source was only in the last years discovered to be a pulsar, although it is known since the early 1970s. 4U 1909+07 is typically detected at a level of about 15 mCrab in INTEGRAL/ISGRI, but can reach about 300 mCrab during flaring
activity. The neutron star exhibits a very long pulse period of 605s and a surprising strongly energy dependent pulse profile. While phase averaged spectra of accreting X-ray pulsars are usually well described
by a powerlaw modified at higher energies by an exponential cutoff, the spectrum of 4U 1909+07 requires an additional blackbody component at low energies. Pulse phase resolved spectroscopy reveals that this blackbody component as well as the cutoff energy are strongly variable with pulse phase while.
23 June Wednesday 2010, at 13.40 FENS G025