Chris Done, Chichuin Jin, Mari Kolehmainen 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

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

Astro-H: Calorimeter

Astro-H: bandpass

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 kTmax often disc-like, plus tail Lower L/LEdd: hard spectrum, peaks at high energies, not like a disc (McClintock & Remillard 2006)

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

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

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

Disc spectra: last stable orbit L/LEdd T4max Ebisawa et 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

Relativistic effects 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 flux Another area where Astro e2 will give major progress in an independent test of the accretion flow models. The accretion disc moves fast in a strong gravitational field, so both special and general relativistic effects modify its spectrum. Doppler shifts and length contraction mean that the emission from the disc moving towards us is blueshifted and boosted, while that moving away is redshifted and suppressed. Then time dilation and gravitational redshift drag everything redwards. The strength of these all effects decrease with radius. All emission from the disc is affected, but its much easier to see on intrinsically narrow features – lines. X-ray illumination of the disc gives iron Kalpha line. Moving inner disc models predict broader line in softer spectra. But the measured line profile can be distorted by narrow absorption features superimposed on the emission. The high spectral resolution of Astro e2 will unambiguously show these, enabling the intrinsic line profile to be measured. Energy (keV) Fabian et al. 1989

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 fcol kT Log n f(n) Log n

Fcol changes but OK <LEdd XMM RXTE Another area where Astro e2 will give major progress in an independent test of the accretion flow models. The accretion disc moves fast in a strong gravitational field, so both special and general relativistic effects modify its spectrum. Doppler shifts and length contraction mean that the emission from the disc moving towards us is blueshifted and boosted, while that moving away is redshifted and suppressed. Then time dilation and gravitational redshift drag everything redwards. The strength of these all effects decrease with radius. All emission from the disc is affected, but its much easier to see on intrinsically narrow features – lines. X-ray illumination of the disc gives iron Kalpha line. Moving inner disc models predict broader line in softer spectra. But the measured line profile can be distorted by narrow absorption features superimposed on the emission. The high spectral resolution of Astro e2 will unambiguously show these, enabling the intrinsic line profile to be measured. Fcol up to 2 so peaks in vfv<4keV for Teff=0.5 keV disc

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’

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

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

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

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

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

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

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

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

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

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

Gladstone Roberts & Done 2008 ULX state ? Gladstone Roberts & Done 2008

Gladstone Roberts & Done 2008 ULX state ? Gladstone Roberts & Done 2008

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

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

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

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

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 – 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

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

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

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