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Black holes: NeXT steps….

Black holes: NeXT steps…. Chris Done University of Durham & ISAS. Black holes. Appearance of BH should depend only on mass and spin (black holes have no hair!) Plus mass accretion rate – L / L Edd 10 4 -10 10 M  : Quasars 10-1000(?) M  : ULX 3-20 M  : Galactic black holes

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Black holes: NeXT steps….

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  1. Black holes: NeXT steps…. Chris Done University of Durham & ISAS

  2. Black holes • Appearance of BH should depend only on mass and spin (black holes have no hair!) • Plus mass accretion rate – L/LEdd • 104-1010 M: Quasars • 10-1000(?) M: ULX • 3-20 M: Galactic black holes • How does accretion flow change as function of M/M spin and L/LEdd ?

  3. Big questions: First BH & galaxies • stellar bulge (s or MB) gives BH mass – link between galaxy and BH • QSO peak at z~2 L/LEdd ~1 onto ~108 M0 (local NLS1) • First SMBH = first galaxies. QSOs z~6, so first BH ~106 M0 z~10? 109 Black hole mass 103 Stellar system mass 106 1012

  4. Big questions:ULX Gao et al 2003 • Ultra - Luminous X-ray sources in spiral arms of nearby starforming galaxies – ULX • L~1039-41 ergs s-1 M~10-1000 M for L<LEdd • Hard for stellar evolution to make BH > 50 M • How to form bigger BH? How to get L/LEdd>1? • Need to know mass!!!

  5. Big questions: BH jet – spin? • Nature of the jet=AGN feedback on cluster cooling! link to spin ? • MRI simulations say powerful jets for moderate spin – don’t need a=0.998. (weak) jet a=0 • LMXB: gravitational waves in core collapse may limit spin to <0.8 (Gammie et al 2002) • AGN: high spin for BH in major mergers (big galaxies) but not from multiple small mergers Radio loud/quiet? • Need to measure spin!!!

  6. Big questions: strong gravity • Accreting BH: huge X-ray luminosity close to event horizon • Bright emission from region of strong spacetime curvature • Spectral distortions depend on velocity, geometry and GR • Observational constraints on strong gravity if we know velocity/geometry! • Need to understand accretion!

  7. Spectra of accretion flow: disc • Differential Keplerian rotation • Viscosity B: gravity  heat • Thermal emission: L = AsT4 • Temperature increases inwards • GR last stable orbit gives minimum radius Rms • a=0: Tmax = (M/M )-1/4 (L/LEdd )1/4 • 1keV (107 K) for 10 M • 10 eV (105 K) for 108 M • a=0.998 Tmax ~ 2.2 Tmax (a=0) • AGN: UV disc, ISM absorption, mass more uncertain. XRB… Log n f(n) Log n

  8. Galactic Binary systems • Disc in X-ray band so not so heavily absorbed as UV • Huge amounts of high s/n data • Variability timescales • ms – year (observable!) • hours – 108 years in quasars • Observational template of accretion flow as a function of L/LEdd onto ~10 M BH • Need ASM… 7 years

  9. X-ray Spectra • Bewildering variety of spectra from single object in XRB! • Underlying pattern • High L/LEdd:soft spectrum, peaks at kTmax often disc-like, plus tail • Lower L/LEdd:hard spectrum, peaks at high energies, not disc! • All GBH in RXTE archive consistent with SAME spectral evolution 10-3 < L/LEdd < 1 • How is hard X-ray tail produced? • Why change with L/LEdd ? Done & Gierlinski 2003

  10. Observed GBH spectra • RXTE archive of many GBH • Same spectral evolution 10-3 < L/LEdd < 1 • Need this sort of data for AGN Done & Gierliński 2003 G (3-6.4) 4.5 3.0 1.5 1.5 1.5 3.0 3.0 4.5 4.5 G (6.4-16) G (6.4-16)

  11. Accretion flows without discs • Disc models assumed thermal plasma – not true at low L/LEdd • Instead: hot, optically thin, geometrically thick inner flow replacing the inner disc (Shapiro et al. 1976; Narayan & Yi 1995) • Hot electrons Compton upscatter photons from outer cool disc • Few seed photons, so spectrum is hard Log n f(n) Log n

  12. Qualitative and quantitative models: geometry Log n f(n) Log n Hard (low L/LEdd) Soft (high L/LEdd) Log n f(n) Log n Done & Gierliński 2004

  13. Moving disc – moving QPO • Low frequency QPO – very strong feature at softest low/hard and intermediate and very high states • Moves in frequency correlated with spectral slope • Moving inner disc makes sense of this. Disc closer in, higher f QPO. But also more soft photons from disc so softer spectra (di Matteo Psaltis 1999)

  14. Qualitative and quantitative models: geometry Log n f(n) Log n Hard (low L/LEdd) Soft (high L/LEdd) Log n f(n) Log n Done & Gierliński 2004

  15. And jet…. • ALL produce jet and are consistent with same radio/X ray evolution • No special mQSO class • Depends on spectrum - maximum radio at brightest low/hard, intermediate and very high states (like QPOs) i.e. L/LEdd (Merloni et al 2003; Falke et al 2004) • Strongly quenched in disky spectra…. Gallo et al 2003

  16. Big questions: X-ray tail – jet? • And link to jet behaviour! Sudden quenching of jet for disky spectra! • Need geometrically thick flow to get large scale B field for jet? • MRI gives jet from accretion flow – more powerful at higher spin but doesn’t require extreme a=0.998 (even present at a=0: Kataoka’s talk) • Need to MEASURE spin Fender Belloni & Gallo 2004

  17. Observed disc spectra: spin? • Pick ONLY disky ones • L/LEddT4max(Ebisawa et al 1993; Kubota et al 1999; 2001) • Proportionality gives Rms i.e. a • Bit tricky as disc not blackbody. Some Compton distortion in upper layers of disc – fcol • Good models now (full vertical disc structure + radiative transfer with metals + full GR) Davis et al 2005 • RANGE a = 0.1-0.8 but NOT extreme (depend on i, M, D) Davis, Done Blaes 2006

  18. Observed disc spectra • Pick ONLY disky ones • L/LEddT4max(Ebisawa et al 1993; Kubota et al 1999; 2001) • Proportionality gives Rms i.e. a • Bit tricky as disc not blackbody. Some Compton distortion in upper layers of disc – fcol • Good models now (full vertical disc structure + radiative transfer with metals + full GR) Davis et al 2005 • RANGE a = 0.1-0.8 but NOT extreme (depend on i, M, D) Gierlinski & Done 2003

  19. Relativistic effects (special and general) affect all emission (Cunningham 1975) Hard to easily spot on continuum components Fe Ka line from irradiated disc – broad and skewed! (Fabian et al 1989) Broadening gives an independent measure of Rin – so spin if ISO (Laor 1991) Models predict increasing width as go from low/hard to high/soft states Relativistic effects flux Energy (keV) Fabian et al. 1989

  20. Problems: extreme Fe lines Miller et al 2004 • Broad iron lines are common in GBH. Some indications of increasing width with spectral softness • But some are extremely broad, indicating high spin (if disc to ISO) and extreme emissivity – tapping spin energy of black hole? (Miller et al 2002; 2003; 2004; Minuitti et al 2004) • BUT these are the same objects for which a<~0.7 from disc spectra • Mainly in VHS and softest low/hard states (intermediate states) flow extends below ISO? B field means not force free so LSO distorted…

  21. XTE J1650-500: real conflict Done & Gierlinski 2005 • QPO and broadband data say that disc not down to ISO (RXTE) • 10-3 < L/LEdd < 1

  22. Extreme line in bright LH state of J1650 Done & Gierlinski 2005 • MECS data (moderate resolution from BeppoSAX) • pexriv+narrow line.Best fit is extreme spin (Rin=2) and emissivity q=3.5 (Miniutti et al 2004) • But ionised reflection – line is intrinsically comptonised (Ross, Fabian & Young 1999)

  23. Reflection from a slab: constant n • Ionisation balance in all these from Done et al 1992 and is VERY approximate! • Slab temperature given rather than calculated! • Constant density ionised disc (CDID/reflion) models of Ballantyne, Iwasawa & Fabian 2001; Ross & Fabian 2005 • Irradiated slab so x and temperature drops as go deeper • Also includes compton UPSCATTERING! SMEARS edge Ross, Fabian & Young 1999 CDID: x=103 pexriv: x=3x103

  24. Extreme line in bright LH state of J1650 Done & Gierlinski 2005 • Proper reflection models: very different shape for ionised reflection – line and edge are intrinsically broadened by Comptonisation in the disc (Ross, Fabian & Young 1999) • Still extreme but relativistic effects only Dc2=13 not 190 as for pexriv. Significance much reduced

  25. Extreme line in bright LH state of J1650 Done & Gierlinski 2005 • Absorption lines – outflow. Rin~10 with normal emissivity. Nh~1023, log x=2-3 • Need strong dip at 7.5keV so either fast outflow at v~0.1c or else strong abs at 7.5 from Ka and/or Ni Kb

  26. Miller et al 2006 Absorbers now commonly seen • GRS1915+105 and J1655-40 in ASCA data (Ueda et al 1998; Kotani et al 2000) • XMM 3 disky spectra. BIG dips - 7.5keV! Also Suzaku x1630 Sala et al 2006, Kubota et al 2006 • Chandra HETG Miller et al 2006 • Chandra absorption lines – outflow of 1500 km/s, broadening by velocity dispersion of similar speeds • Probably not line, thermal or radiation driven wind, so magnetic from inner disc? • What is the effect of this on the disc structure??

  27. High frequency QPO’s • 2 tiny features – give small radius • ..frequencies harmonically related 2:3 RESONANCE. but which?? • Orbits in GR: (Stella & Vietri 1998) • v(circ, plane) • v(circ, vert) • v(ellipse, plane) • Coupled by gas dynamics so can get ‘parametric’ 2:3 resonance between vertical and radial perturbations – requires a>0.95 for GBH where disc says lower… • But if large scale height flow then also compressive modes then radius larger, and no strong constraint on a. Depend on M, a, R

  28. High frequency QPO’s • 2 tiny features – give small radius • ..frequencies harmonically related 2:3 RESONANCE. but which?? • Orbits in GR (stella & vietri 1998) • f(circ, plane) • f(ellipse, plane) • f(circ, vert) • Coupled by gas dynamics so can get ‘parametric’ 2:3 resonance between vertical and radial perturbations – a>0.95 (Abramovicz et al 2000) BUT disc says lower… • But if large scale height flow then also compressive modes then radius larger, and no strong constraint on a (Blaes et al 2006) Depend on M, a, R

  29. Big questions: summary • Understand accretion flow at 10-3 L/LEdd < 1 in GBH truncated disc, hot inner flow with jet disk to last stable orbit, no hot flow, no jet (extreme) • Measure spin to test how accretion flow produces jets disk spectra - L T4 – depends on vertical structure broad iron lines – depends on absorption high frequency QPO’s – depends on identifing QPO • Use understanding of flow to test GR – even with extremely broad lines then its fairly Einsteinian. No more than factor 2, strongly limits higher order curvature modifications to gravity

  30. Big questions: summary • Need comparable data quantity and quality on AGN in this range of L/LEdd – how does flow properties scale with mass? maximum hard X-rays from brightest low/hard state – CXB? • Understand accretion flow at L/LEdd > 1 nature of ULX (GBH at high L/LEdd show low T disc) How do winds affect the disc structure NLS1’s (T Boller) use to predict AGN spectra at peak of QSO activity z~2 use to predict first BH spectra in early universe

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