Be/X-ray binaries

1. Are there atoll/Z sources in HMXB?A rapid aperiodic timing analysis of 4 accreting X-ray pulsars in outburstPablo ReigIESL, Foundation for Research & Technology-HELLASAstronomy Group, Physics Dept. University of Crete

2. Be/X-ray binaries • HMXB • Be + NS • Accreting X-ray pulsars • Mainly transients • Two types of outbursts Type I:Lx < 1037 erg/s, (quasi)periodic Porb, short Type II: Lx ~1037-1038 erg/s, unpredictable, long

3. van der Klis (2006)‏ CD in LMXBs Atoll sources Z sources

4. CD in HMXBs • two branches • horizontal at low Lx • diagonal at intermediate & high Lx • HC makes the difference • 4U 0115+63, EXO2030+375 & KS1947+300 • as flux increases SC decreases, HC increases • V 0332+53 • as flux increases SC decreases, HC decreases

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6. Hardness-Intensity Diagrams

7. Ll LLF Lb Ll LLF Lu Lb Lu Lb'' Lb' van Straaten et al. (2002)‏ Belloni et al. (2002)‏ PSD in LMXBs Atoll source Z source νmax =(ν02 + Δ2)1/2 Δ=FWHM/2

8. multi-Lorentzian profile • 4 BLN (Lb, Ll, Lu, Lu’) & 2 PN ≈ QPO (LLF, Ls) • νb < νLF < νl < νu • νs ≈ νspin --> coupling periodic/aperiodic var.

9. PSD in HMXBs Lb Ll LLF Ls

10. PSD in HMXBs Lb Ll LLF Ls

11. PSD in HMXBs Lb Ll Lu Lu'

12. PSD in HMXBs Lb Ll Lu

13. HMXB vs LMXB: similarities • two different types • 4U 0115+63, EXO 2030+375, KS1947+300 • V 0332+53 (~ Z)‏ • spectral branches • smooth motion without jumps • horizontal branch • low flux & high rms • PSD: multi-Lorentzian • broad (zero-centred L) noise for low and high frequencies • peaked noise for intermediate frequencies

14. HMXB vs LMXB: differences • different topology • slower motion along the branches • hr-days in LMXBs, days-weeks in HMXBs • ~ one order of magnitude longer time scales • mHz QPOs, ν ~ 0.001-0.1 Hz typically • Ls noise • associated with the pulse noise • no apparent correlation between spectral parameters (characteristic frequencies, rms) Mdot