The Broad Iron Line Profile of XTE J1650-500

1. The Broad Iron Line Profile of XTE J1650-500 DOM WALTON IoA, Cambridge, UK In collaboration with Rubens Reis, Ed Cackett, Jon Miller and Andy Fabian Berlin: 2011

2. BLACK HOLE ACCRETION f f   Dom Walton Berlin: 2011

3. AGN SPECTRA 1H 0707-495 - Zoghbi et al. (2010) (see also Fabian et al. 2004, Boller et al. 2002, etc.) Dom Walton Berlin: 2011

4. BLACK HOLE ACCRETION f f  Dom Walton Berlin: 2011

5. DISC REFLECTION f f  Dom Walton Berlin: 2011

6. RELATIVISTIC EFFECTS Characterising the reflection component is one way in which we can measure BH spin Fabian et al. (2000) Dom Walton Berlin: 2011

7. BLACK HOLE BINARIES • Spectra obtained from Galactic black hole binaries (BHBs) show the same primary continuum components as AGN: • Many also display broad excesses at ~6 keV • BHBs are brighter due to their proximity, so any absorption features can be well constrained • Thermal emission (accretion disc, low energy) • Comptonised emission (corona, high energy) Dom Walton Berlin: 2011

8. XTE J1650-500 • 2001 outburst observed by XMM (burst mode, x1) and BeppoSAX (x3) • Displays a broad excess at ~6 keV, independent of Comptonised continuum model: • Gaussian: σ = 1.2 ± 0.2 keV • Laor: Rin = 1.5 ± 0.1 RG Dom Walton Berlin: 2011

9. XTE J1650-500 • 2001 outburst observed by XMM (burst mode, x1) and BeppoSAX (x3) • Displays a broad excess at ~6 keV, independent of Comptonised continuum model: • Note residual instrumental features at ~1.8 and 2.2 keV • Gaussian: σ = 1.2 ± 0.2 keV • Laor: Rin = 1.5 ± 0.1 RG Dom Walton Berlin: 2011

10. DISC REFLECTION MODEL - Powerlaw - Relativistic disc reflection (incl. thermal continuum) REFBHB (Ross & Fabian, 2007); Rin ~ 2 RG Dom Walton Berlin: 2011

11. SOFT RESIDUALS • Soft residuals at ~0.8 keV persist. Possible astrophysical origins: • Comparison with burst mode Crab data shows similar residuals, so likely to be systematic • Doesn't effect inner radius obtained (always ~2 RG) • Additional reflected OVIII emission and/or Neon absorption in the ISM • Local ionised absorption (disc wind) Dom Walton Berlin: 2011

12. INSTRUMENTAL EFFECTS There are claims the line profiles obtained could be broadened and skewed by instrumental effects, e.g. pile-up, charge transfer inefficiency. Comparison with contemporaneous BeppoSAX MECS data (obtained ~1 day prior to XMM observation): • The line profile is independent of detector type (MECS detectors are gas based) • Profile is not significantly modified by instrumental effects Dom Walton Berlin: 2011

13. COMPTON BROADENING • Compton broadening in the disc is self-consistently included in REFBHB • 'Windline' models run into problems with the mass outflow rates required • Electron temperature (~6 keV) and optical depth (~1) required to broaden the line in the corona are not consistent with those found for the continuum • Also expect the line centroid energy to increase by ~0.35 keV, but EG < 6.5 keV Dom Walton Berlin: 2011

14. LINE PROFILE EVOLUTION • Latter two BeppoSAX observations were obtained later in the evolution of the outburst • Line profiles obtained do not show significant deviations from early BeppoSAX and XMM observations • This is not consistent with the expected behaviour for scenarios dominated by electron scattering Dom Walton Berlin: 2011

15. XTE J1650-500 SPIN 0.84 ≤ a* ≤ 0.98 (90% confidence) Dom Walton Berlin: 2011

16. MCG -6-30-15 • Seyfert 1.2 AGN, 350 ks XMM observation taken in 2001 • Spectrum complicated by a warm absorber, accounted for by the model of Chiang & Fabian (2011) • Also displays a broad excess at ~6 keV Absorption model includes: • Fast, highly ionised component • 2 slow, lower ionisation components • Iron-L dust absorption Dom Walton Berlin: 2011

17. LINE PROFILES Dom Walton Berlin: 2011

18. LINE PROFILES Dom Walton Berlin: 2011

19. COMMON ORIGIN • As the excesses at ~6 keV broad iron lines observed in AGN and BHBs are similar, we would like to find a common physical origin for them. • Absorption does not (usually) significantly modify the spectra of BHBs • Reflection from the inner accretion disc is the only viable common interpretation Dom Walton Berlin: 2011

20. SUMMARY • The BHB XTE J1650-500 displays a broad iron line profile (see also earlier works by Miller+ 2002, 2009, Miniutti+ 2005) • The line profile requires that the emission arises in the regions of strong gravity close to the black hole, and is similar to those seen in AGN • As BHBs provide an unobscured view of the accretion flow, relativistic disc reflection must be a fundamental process in the disc-corona geometry • Comparison with BHBs therefore provides a strong argument in favour of the presence of relativistic disc reflection in AGN Dom Walton Berlin: 2011

21. EPFAST • EPFAST attempts to correct for the features at ~2 keV; applies an energy independent correction • CTI is energy dependent (CTI ~ E-0.5); EPFAST over-corrects at iron K energies EPFAST Dom Walton Berlin: 2011