6533b857fe1ef96bd12b443b
RESEARCH PRODUCT
The pre-outburst flare of the A 0535+26 August/September 2005 outburst
Richard E. RothschildKonstantin PostnovAndrea SantangeloIngo KreykenbohmColleen A. WilsonAscension Camero-arranzPeter KretschmarD. KlochkovMark H. FingerIsabel CaballeroRuediger StaubertKatja PottschmidtKatja PottschmidtSlawomir SuchyJörn Wilmssubject
Astrophysics::High Energy Astrophysical PhenomenaX-ray binarymagnetic fields [Stars]FOS: Physical sciencesChamp magnetiqueAstrophysicsPhoton energyAstrophysicslaw.inventionPulse periodAccretion disclaw:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Fuentes de Rayos X [UNESCO]X-rays : binaries; Stars : magnetic fields; Stars : individual : A 0535+26UNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Fuentes de Rayos XAstrophysics::Solar and Stellar AstrophysicsSpectral analysisPhysicsAstrophysics (astro-ph)Astronomy and AstrophysicsSpace and Planetary ScienceHigh massbinaries [X-rays]individual : A 0535+26 [Stars]UNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::EstrellasFlare:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Estrellas [UNESCO]description
We study the spectral and temporal behavior of the High Mass X-ray Binary A 0535+26 during a `pre-outburst flare' which took place ~5 d before the peak of a normal (type I) outburst in August/September 2005. We compare the studied behavior with that observed during the outburst. We analyse RXTE observations that monitored A 0535+26 during the outburst. We complete spectral and timing analyses of the data. We study the evolution of the pulse period, present energy-dependent pulse profiles both at the initial pre-outburst flare and close to outburst maximum, and measure how the cyclotron resonance-scattering feature (hereafter CRSF) evolves. We present three main results: a constant period P=103.3960(5)s is measured until periastron passage, followed by a spin-up with a decreasing period derivative of Pdot=(-1.69+/-0.04)x10^(-8)s/s at MJD 53618, and P remains constant again at the end of the main outburst. The spin-up provides evidence for the existence of an accretion disk during the normal outburst. We measure a CRSF energy of Ecyc~50kev during the pre-outburst flare, and Ecyc~46kev during the main outburst. The pulse shape, which varies significantly during both pre-outburst flare and main outburst, evolves strongly with photon energy.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-01-21 |