What do we know about L~Ledd accretion – BHB, ULX – and how does Astro -H help?

1. What do we know about L~Ledd accretion – BHB, ULX –and how does Astro-H help? Chris Done, Chichuin Jin, Mari Kolehmainen University of Durham

2. Astro-H • Next Japanese X-ray satellite due for launch in Dec 2015 • Calorimeter 5eV spectral resolution • Broad bandpass 0.5-500 keV

3. Astro-H: Calorimeter

4. Astro-H: bandpass

6. Black hole binaries • Observe dramatic changes in SED with mass accretion rate onto black hole • Dramatic changes in continuum – single object, different days • Underlying pattern in all systems • High L/LEdd:soft spectrum, peaks at kTmaxoften disc-like, plus tail • Lower L/LEdd:hard spectrum, peaks at high energies, not like a disc (McClintock & Remillard 2006)

7. Moving disc – moving QPO • Energy spectra: disc moves 50-6ish Rg as make transition • Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant! • Large radius moves, Small radii constant

8. Moving disc – moving QPO • Energy spectra: disc moves 50-6ish Rg as make transition • Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant! • Large radius moves, Small radii constant

9. Variability of disc • L/LEddAT4max(Ebisawa et al 1993; Kubota et al 1999; 2001) • Constant size scale – last stable orbit!! BH spin

10. Disc spectra: last stable orbit • L/LEddT4maxEbisawaet al 1993; Kubota et al 1999; 2001 • Constant size scale – last stable orbit!! • Not quite as simple as this • BHSPEC - Proper relativistic emissivity (Novikov-Thorne) • corrections for spectrum not being blackbody (fcol) • Corrections for relativistic propagation effects Davis et al 2005 Kolehmainen & Done 2010

11. Relativistic effects (special and general) affect all emission (Cunningham 1975) Emission from the side of the disc coming towards us is blueshifted and boosted by Doppler effects, while opposite side is redshifted and suppressed. Also time dilation and gravitational redshift Broadens spectrum at a give radius from a narrow blackbody Relativistic effects flux Energy (keV) Fabian et al. 1989

12. fcolkT Theoretical disc spectra • Surely even disc spectra aren’t this simple!!!! • Disc annuli not blackbody – too hot, so little true opacity. Compton scattering important. • Modified blackbody Shakura & Sunyaev 1973 • Describe by colour temperature fcol • And relativistic smearing effects on the spectra at each radius kTeff Log n f(n) Log n

13. Fcol changes but OK <LEdd XMM RXTE • Fcol up to 2 so peaks in vfv<4keV for Teff=0.5 keV disc

14. BHB Disc spectra:10 M L/LEdd~1 Kolehmainen et al 2013 • LMC X-3 • Peak at 3.5 keV for ~0.8LEdd • 3.5 x (10/107)1/4~0.1keV for 107 AGN (Ross, Fabian & Mineshige 1991) • ‘broadened disc’

15. Moving disc – moving QPO • Energy spectra: disc moves 50-6ish Rg as make transition • Power spectra: low frequency break moves correlated with QPO, high frequency power more or less constant! • Large radius moves, Small radii constant

16. Radius no longer constant! • Radius can be higher or lower when disc NOT dominant (steep PL) • Don’t do this!! very high disk dominated high/soft Kubota & Done 2004

17. Very High State: Spectrum Kubota & Done 2004 • Disc AND tail have roughly equal power. BE CAREFUL!!! • Now depends on models - Comptonized spectrum is NOT a power law close to seed photons! Log n f(n) • Disc dominated(low L / high L) • Very high state (comp < disc) • Very high state (comp > disc) Log E

18. Very High State: Spectrum Kubota & Done 2004 • Disc AND tail have roughly equal power. BE CAREFUL!!! • Now depends on models - Comptonized spectrum is NOT a power law close to seed photons! Log n f(n) • Disc dominated(low L / high L) • Very high state (comp < disc) • Very high state (comp > disc) Log E

19. Very High State: photons Kubota & Done 2004 • But Comptonised photons come from the disc – optically thick so suppresses apparent disc emission • Correct for this Log n f(n) Log E

20. Very High State: energy Kubota & Done 2004 • But ENERGY of corona came from disc as well. Lower T under corona but more importantly lower L enhancing outer disc L(R) R-3 R

21. Very High State: energy Done & Kubota 2005 • But ENERGY of corona came from disc as well. Lower T under corona but more importantly lower L enhancing outer disc (Svensson & Zdziarski 1994) L(R) R-3 R

22. Disk + Compton! Bandpass!! • All high L states have disc plus tail • Disc – low E, constant on short timescales • Compton – high E, varies on short timescales • Steep power law state is HARD at low E

23. Disk + Compton! Bandpass!! • XTEJ1550-564 • ASCA-RXTE-OSSE • Steep power law state is HARD at low E • low kTbb~0.6keV, high kTe~20keV compared to ULX

24. GRS1915+105 (Nh 4-6e22!) kTe~7keV kTe~3keV Done et al 2004

25. ULX state ? Gladstone Roberts & Done 2008

26. ULX state ? Gladstone Roberts & Done 2008

27. Modifies optical continuum • X-rays illuminate outer disc where intrinsic flux is low so reprocessed can dominate (van Paradijs 1996) • SWIFT/XMM X-opt simultaneously • XTE J1817-330 - trace scattered fraction through outburst SWIFT+RXTE • Lopt ~ 0.002 Ldisc in high/soft state. • Big changes at transition to low/hard state…. Gierlinski Done & Page 2007

28. Luminosity >LEdd ? • Standard disc assumes that energy liberated locally through mass accretion is radiated locally • Not necessarily true – can be carried radially along with the flow is accretion timescale < radiated timescale • Optically thick advection – slim discs (Abramowicz et al 1988) only different L>LEdd • Heats next ring in – but can advect that also. Then lose does the black hole! • L=LEdd log(1+mdot/mdotEdd) Log n f(n) Log n

29. Luminosity >LEdd ? • Standard disc assumes that energy liberated locally through mass accretion is radiated locally • Not necessarily true – can be carried radially along with the flow is accretion timescale < radiated timescale • Optically thick advection – slim discs (Abramowicz et al 1988) only different L>LEdd • Heats next ring in – but can advect that also. Then lose does the black hole! • L=LEdd log(1+mdot/mdotEdd) Log n f(n) Log n

30. Luminosity >LEdd ? • Standard disc assumes that mdoty constant with R • Not necessarily true – can lose mass in a wind is L>LEdd (Shakura & Sunyaev 1973) • L=LEdd log(1+mdot/mdotEdd) i.e. same as before but for different reason Log n f(n) Log n

31. Luminosity >LEdd ? • Standard disc assumes that mdotyconstant with R • Not necessarily true – can lose mass in a wind is L>LEdd(Shakura & Sunyaev 1973) • L=LEdd log(1+mdot/mdotEdd)i.e. same as before but for different reason – local flux at disc surface has to be <LEdd • Two possible responses – so disc probably does both as seen in numerical simulations Log n f(n) Log n

32. Modifies optical continuum • Expect f_opt,int/f_x to increase • X-rays decrease via advection and/or mass loss • Optical determined by irradiation – depends on geometry • If see irradiation then CAN’T be strongly beamed

33. Modifies optical continuum • Expect f_opt,int/f_x to increase • X-rays decrease via advection and/or mass loss • Optical determined by irradiation – depends on geometry • If see irradiation then CAN’T be strongly beamed • M81 X6 Sutton et al 2014

34. Conclusions: • BHB spectral states: disk (low E) plus tail (high E) • Bandpass makes a difference RXTE (BHB) XMM (ULX) • High L~Ledd can show disc (constant radius) • Fraction illuminating outer disc is small • Disky ULX – fraction illuminating outer disc small • Or very high state – larger size scale, lower kTe– connects to ULX? • But then got more extreme ULX states – higher mdot? • fopt determined by irradiation – so irradiating disc so not highly collimated…. • NOT like expect for mdot~1000