The geometric origin of quasi-periodic oscillations in black hole binaries

Transcription

1 X-ray Universe 2014 Dublin - 17 th June The geometric origin of quasi-periodic 6000 oscillations in black hole binaries GRS Adam Ingram Michiel van der Klis, Chris Done Time (s)

2 Black Hole Binaries 2/22 Unique laboratories for relativity Too small to directly image Must infer geometry from spectral & timing properties

3 Truncated Disk Model 3/22 Multi-coloured blackbody, Comptonisation and Reflection Flux Energy Flux Energy (kev) e.g. Done, Gierlinski & Kubota (2007)

4 Energy Flux Truncated Disk Model 4/22 State changes from moving truncation radius (R g =GM/c 2 ) R o ~60R g R o ~6R g Gilfanov (2010) Energy (kev)

5 Quasi-periodic oscillations 5/22 X ray Brightness Time (s) (rms/mean) X-Ray Counts/s ν qpo ~ Hz as R o ~60-6 R g Frequency (Hz)

6 Quasi-periodic oscillations 5/22 X-Ray Counts/s X ray Brightness Time (s) Higher inclination objects have stronger QPOs Motta et al (2014); Heil, Uttley & Klein-Wolt (2014)

7 Frame dragging 6/22 A spinning black hole distorts space and time The satellite s motion is influenced by the spin of the black hole Lense & Thirring (1918) Stella & Vietri (1998)

8 Frame dragging 7/22 FLOW DISK Solid body precession at average LT frequency Fragile et al (2007) Viscosity aligns inner regions with the BH and outer regions with the binary partner Bardeen & Petterson (1975)

9 Frame dragging 8/22 X ray Brightness Time (s) Ingram, Done & Fragile (2009)

10 Frame dragging 9/22 Tell-tale sign of relativistic precession: a rocking iron line Flux Ingram & Done (2012) Energy

11 Phase Resolving 10/22 Time Flux Flux X-ray Brightness Energy Energy

12 Phase Resolving 11/22 Energy Flux Energy Geometric origin è Line EW varies

13 Phase Resolving 11/22 Energy Flux Energy Geometric origin è Line EW varies

14 Phase Resolving 12/22 Energy Flux Energy Non-geometric origin è Line EW in phase with continuum

15 Phase Resolving 12/22 Energy Flux Energy Non-geometric origin è Line EW in phase with continuum

16 QPO waveform 13/22 Periodic function: constant phase difference 1 st Harmonic 2 nd Harmonic Total Cycles Ingram & van der Klis (in prep)

17 QPO waveform 13/22 Periodic function: constant phase difference 1 st Harmonic 2 nd Harmonic Total Cycles Ingram & van der Klis (in prep)

18 QPO waveform 14/22 Quasi-periodic function: changing phase difference X ray Counts/s Time (s) but does the phase difference vary randomly or around a well defined mean?

19 QPO waveform 14/22 Quasi-periodic function: changing phase difference X ray Counts/s Time (s) Split long light curve into many segments and measure the phase difference ψ for each segment

20 QPO waveform 15/22 Phase difference varies around a mean: there is an underlying waveform N o of segments (normalised) / Ingram & van der Klis (in prep)

21 QPO waveform 15/22 Phase difference varies around a mean: there is an underlying waveform N o of segments (normalised) Obs 1 Obs 2 Obs 1: ν qpo ~0.46Hz Obs 2: ν qpo ~2.25Hz / Ingram & van der Klis (in prep)

22 QPO waveform 16/22 Phase difference varies around a mean: there is an underlying waveform Counts/s Obs 1 Obs Obs 1: ν qpo ~0.46Hz Obs 2: ν qpo ~2.25Hz Phase (QPO cycles) Ingram & van der Klis (in prep)

23 QPO waveform 17/22 Enables waveform fitting of QPO models Obs 1 Counts/s Obs Phase (QPO cycles) Flux Precession angle (radians)

24 Phase resolving 18/22 Can now reconstruct waveform in each energy band using phase lag with the full band Lag (cycles) Lag (cycles) Obs 1 Obs 2 Fractional RMS Energy (kev) Energy (kev) Ingram & van der Klis (in prep)

25 Phase resolving 19/22 Spectra for 4 snapshots of phase Obs 1 Obs 2 Ratio Ratio Energy (kev) Energy (kev) Ingram & van der Klis (in prep)

26 Phase resolving 20/22 Observation 1 Observation 2 Counts/s Counts/s kt bb (kev) kt bb (kev) EW (ev) EW (ev) Phase (QPO cycles) Phase (QPO cycles) Ingram & van der Klis (in prep)

27 Phase resolving 21/22 Counts/s GX339 4 High reflected, low direct Small! kt bb (kev) Low reflected, high direct Small! EW (ev) Phase (QPO cycles) Ingram, van der Klis & Done (in prep)

28 Phase resolving 21/22 Counts/s GX339 4 High reflected, low direct Small! kt bb (kev) Low reflected, high direct Small! EW (ev) Phase (QPO cycles) Ingram, van der Klis & Done (in prep)

29 Conclusions 22/22 The QPO does have an underlying waveform Waveform fitting will provide a diagnostic tool Modulations seen in spectral parameters: photon index, disk temperature & Fe line equivalent width Variation in Fe line equivalent width is strong evidence for geometric QPO origin Need better data to see a rocking iron line shape

30

31 Testing precession ratio Model Energy (kev) Ingram & Done 2012b

32 Testing precession ratio RXTE PCA: 5ks Energy (kev) Ingram & Done 2012b

33 Testing precession ratio XMM EPIC pn: 5ks Energy (kev) Ingram & Done 2012b

34 Testing precession ratio XMM EPIC pn: 100ks Energy (kev) Ingram & Done 2012b

35 Testing precession ratio LOFT LAD: 5ks Energy (kev) Ingram & Done 2012b

36 Phase resolving 19/21 Observation 1 Observation 2 Counts/s Counts/s kt bb (kev) kt bb (kev) EW (ev) line flux line flux EW (ev) Phase (QPO cycles) Phase (QPO cycles)

37 Phase resolving 20/21 GX339 4 Counts/s High reflected, low direct Small! line flux kt bb (kev) Low reflected, high direct Small! EW (ev) Phase (QPO cycles) Ingram, van der Klis & Done (in prep)

38 Quasi-periodic oscillations 5/22 X ray Brightness Time (s) (rms/mean) X-Ray Counts/s Frequency (Hz) QPO from inner regions