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What Makes them Black Holes

What Makes them Black Holes. Other than the classical Rees argument about efficiency, size and luminosity what observational properties make these objects black holes ? High mass in a small volume via direct measurements SGR A*, NGC4258 etc Mass functions of stellar systems

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What Makes them Black Holes

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  1. What Makes them Black Holes • Other than the classical Rees argument about efficiency, size and luminosity what observational properties make these objects black holes ? • High mass in a small volume via direct measurements SGR A*, NGC4258 etc • Mass functions of stellar systems For the vast majority of objects thought to be black holes such information is not available • We must use indirect observational data • Spectra • Timing • Spectral/timing (reverberation mapping) • Imaging (micro-lensing) • E.g. things that look like other BHs are also BHs Why are black hole interesting today • Black Holes and Strong Gravity • Spectral and timing probes of strong gravity • Astrophysics in the strong gravity region • AGN Winds & effect of BHs on cosmic structure • Outflows from AGN • Cooling flow and cluster entropy problems • Role of AGN in galaxy formation • Evolution of AGN and SMBH growth • Paradigm shift in AGN evolution

  2. X-rays • I will focus on the x-ray properties for several reasons • Many galactic black holes (GBH) optical spectra and light curves show weak/complex evidence for the black hole- All (but 1?) GBH found by x-ray survey • The space density of x-ray selected AGN is much higher than that of optically selected AGN (Hasinger) 126/286 Not detected by HST in z’ Nuclei often 5 mags fainter than expected; at 3000A N(H)~1022 atm/cm2 for MW dust to gas ratio (Barger et al 2005) X-rays show the highest amplitude/shortest timescales of variation Only spectral feature from near the event horizon

  3. AGN Black Holes Across the Mass Spectrum • This is a very large topic and I cannot cover everything • In particular I will not cover radio emission and recommend the book From X-Ray Binaries to Quasars: Black Holes on All Mass Scales Maccarone, Fender, Ho, and the review article by G. Fabbiano. in :Memorie della Societa Astronomica Italiana, v.77, p.728 (2006) I will also not talk about spin- original or otherwise Many of the topics in this talk have been the subject of whole meetings Broad Fe K line Power density spectra Spectral transitions in black holes etc etc And thus the the presentation here is ‘superficial’ Winds Binary Mass donor star Accretion disk Jets Blandford

  4. Black Holes Across the Mass Scale • There exist a wide range of black hole masses • MW ‘Stellar’ mass black holes M< 20M (formed from well understood stellar evolution processes- Fryer and Kalogera 2003) -talk by Casares • “Massive’ Black holes at the centers of galaxies M >3x105 M whose origin is not clear • Perhaps ‘intermediate mass’ black holes 20>M>103 M whose existence is controversial and whose origin is not understood (Makishima etc) Mass Distribution of Milky Way Black holes Kubota 2005 No M>M 18 objects in Milky Way

  5. Black Holes Across the Mass Scale Mass of Black Holes in Center of Galaxies Barth et al 2005 Precision masses (MW, M31, M32< NGC4258) show factor of 3 scatter in relation • There exist a wide range of black hole masses • For black holes at the centers of galaxies there is a strong correlation of black hole mass and stellar velocity dispersion (Gebhardt et al, Ferrarese et al) • For AGN- the masses of the black holes derived via ‘reverberation’ observation agree with the same scaling relations (Peterson et al 2005) • Perhaps ‘intermediate mass’ black holes 20>M >105 M whose existence is controversial and whose origin is not understood (more later) 109 107 105 103

  6. Black Holes Across the Mass Scale Mass of AGN Black Holes vs quiescent Galaxies Peterson 2005 • Using stellar velocity dispersion as a scaling parameter the mass of AGN black holes and ‘passive galaxy’ black holes is very similar (Peterson 2005) • It is secure that black holes exist (see talk by Genzel) 109 107 105 104 M31model of BH vs data Black hole mass from reverberation AGN Mass- filled circles Passive galaxies -open Mass function for a stellar mass GBH

  7. How do we know how massive they are? • In ~20 nearby galaxies the velocity of gas (including masers) and/or stars near the black hole has been measured- velocity law implies a central black hole • Using Kepler’s law the masses have been measured.-precision masses exist for only a few objects. Mass Model for ctr of MW Velocity of Gas near M87 nucleus (Harms et al) Genzel et 2005

  8. Most of the nearby black holes are quiescent • Many nearby black holes are extremely dim in x-ray and optical band (Soria et al 2006)- the bolometric corrections are not known, but are typically ~10-20 • many x-ray black hole transients in their quiescent state are 104-107 times dimmer than in ‘on’ state • It is not yet clear what property makes a black hole active- either for AGN or GBHs Log Lx/LEdd Log M(dot)/MBondi

  9. Micro-lensing can constrain size of ‘light’ source • In practice one measures the size of the emitting regions • The x-ray emission region is smaller than the optical • The optical emission region is larger than that predicted by standard disk models • Multi-wavelength lensing measurements (Pooley et al 2006) allow measurements of the size of the emission line region in different wavelength bands - in principle test the actual physical size of quasars M=3x108 standard accretion disk size

  10. Orbiting Spots Near the Black Hole ( Matt, Reynolds) Spin parameter • Recent evidence has show that some AGN show ‘rapid’ changes in part of the Fe K line profile (Turner et al 2003, Iwasawa et al 2004) • If these changes can be interpreted as rotating ‘hot spots” (Dovciak et al 2005,Goosman 2006) the mass can be estimated ? 20000 60000 10000 sec

  11. Reynolds et al

  12. Typical X-ray spectra in different GBH ‘states’ • There is a strong correlation between the Eddington ratio of a GBH and its x-ray spectra • As one moves from ‘low-hard’ to ‘high’ to ‘ultrasoft’ the Eddington ratio increases and the spectra gets ‘more’ thermal in nature (e.g. more of the bolometric luminosity is carried by a component which can be associated with an optically thick disk, thermal disk) • This transition has never been seen in an AGN-may have been seen in ‘AGN’ transients (Komossa et al 2005) • ULX sometimes show transitions in the opposite sense • In the very high state the spectrum is highly Comptonized • Some of these properties are unique to black holes and are never seen in neutron star spectra AD?

  13. X-ray Spectra of Accreting Compact objects • In a large x-ray spectral survey of x-ray spectra in the MW Done and Gierlinski have shown that there is a spectral region which NS never visit. • They interpret this as evidence that BHs do not have a surface and NS do • GBHs never have x-ray bursts (nuclear burning on the surface) or x-ray pulses • All AGN spectra are in the GBH regions, some ULX have spectra in ‘NS’ region (Winter et al 2006) Open circles black holes , colors Neutron stars Hatched region never visited by NS

  14. Neutron Star and Black Hole Spectra NS BH

  15. Blacks Holes in Quiescence (104 -108 times dimmer ) • McClintock et al (2004) • black holes in ‘quiescence’( a situation in which the accretion rate is very low) are • much dimmer than NS in ‘quiescence” • because they have a horizon through which they ‘swallow’ the advected energy? - • e.g Black holes are black • So far not seen in AGN or ULXs - impossible today to follow AGN or ULX at 105 lower flux ! X-ray luminosity vs orbital period Black holes are black circles Log Lmin 30 32 34 Porb (the mass accretion rate is highly sensitive to the orbital period)

  16. Scaling relations • Seyfert galaxies (AGN) and galactic black holes both show high amplitude rapid, aperiodic x-ray variability spanning several orders of magnitude in frequency. • This noise shows a relatively steep PDS at high frequencies (red noise) and is flatter at low frequencies Black hole grand unification- Uttley 2006 • The physical origin of this noise is not known( but see Goosmann et al 2006 and Lyubarskii and Kotov, Churazov & Gilfanov) , but both its PDS shape and amplitude differ only subtly from neutron star x-ray binaries (Uttley 2006) • Frequently the hard photons lag the soft photons in both AGN and GBHs

  17. Time Variability Gierlinski and Zdziarski 2003 • All accreting compact objects vary. • Is there some signature of a black hole and of its mass in the time variability domain? sec 2 AGN Edelson and Markowitz Days

  18. AGN Light curves in different wavelengths x-ray UV radio

  19. Power density Spectra(figures from v.d. Klis) At low frequencies ( n <100 Hz) the PDS of NS and GBHs are very similar correlations of QPO components are also similar Highest v show most differences-inner part of accretion disk? Only NS have ‘paired’ kilo-hertz QPO- they show a lot of variation and low harmonic content break frequency vs. low n QPO) Black holes (dots), various ‘types of NS (z’s, atolls etc) ) Fastest phenomenon in BHs is at 100-450Hz do not change and have high harmonic content In ULXs the QPO frequency changes so cannot be analog of HF QPO of GBHs PDS of NS (left) BH (right)

  20. Black Hole Power Density Spectra • In galactic black holes (and AGN???) there is a strong connection between the photon spectrum and the power density spectrum (McClintock and Remillard 2003) • This is thought to be related to the physics of the inner accretion disk In the low and very high state there is a change of slope - a break frequency High state Low state Very High state Power Density Spectrum Photon spectrum

  21. Power density Spectra L<0.2 LEdd L>0.2 LEdd AGN PDS It is not yet clear if we can assign ‘high’ state or ‘low’ state PDS to AGN

  22. AGN X-ray Spectral Components “Power-law” emission via thermal Comptonization of seed disc (UV) photons Soft excess - hard tail of thermal disc emission in EUV (big blue bump) Warm absorber/Emitter - ionized gas outflowing from nucleus (lightdays - parsec scale) Iron line emission - accretion disk, BLR, torus, NLR Compton Reflection - off optically thick matter (disc, torus) Reeves 2005

  23. Broad Band Spectrum of Black Holes Esin et al 2001 Zdziarski et al • Qualitatively the broad band spectra of AGN and GBHs are similar- however the effective temperature of the ‘soft black body’ is much lower in AGN appearing in the optical/UV band Cyg X-1 ratio of a Power Law Suzaku data 14 16 18 20 Log n soft excess narrow Fe (6.4keV) Cutoff (Te=110keV) For GBHs kTsoft~0.7-2 keV AGN kTsof~0.1 keV ULX kTsoft ~0.1-1 keV

  24. AGN SED High Z absorbed QSO Hasinger

  25. SED of AGN • Recent very large samples of AGN show systematic trends in the SED- but, so far, no good equivalents of the high state GBH spectra • A ‘special’ class of AGN (NLSY1s ) are thought to be the cognate of High state GBHs but their SED is not a good match Elvis 1994 Van Duyne et al. 2006 SED sorted by L(x) Barger et al 2005

  26. Spectral Variability • Even in a given ‘state’ the spectral shape can vary • Thus values like the PL slope and kTBB are not unique for a given object and ‘state’ Ratio of x-ray spectrum of Cyg X-1 to a power law Gilfanov

  27. Possible Spectral Signature of IMBH • The Effective temperature of the accretion disk scales as kTcol<0.4 keV M> 700 M for L=LEdd Only if L<< LEdd can the temperature be low for a lower mass object  J.Miller et al Two sources in NGC 1313

  28. The Temperature Luminosity Relation • Miller et al 2004 show • galactic black hole candidates have BB component temperatures appropriate for their dynamical masses and observed luminosities • If the BB components in ULXs are not indicative of their mass then additional (unknown) physics is required to account for the BB component- no sign of warm absorber in ULX spectra- clearly see ‘cold’ ISM features due to O and Fe • R. Soria presentation X-ray luminosity (0.5-10) keV x1040 kTBB L/LEdd~0.3,M=1600M L/LEdd~0.01; M=7M L/LEdd~1; M=7M

  29. The Continuum form of AGN, ULX and GBHs • The low state of GBHs and most AGN spectra can be well characterized by a power law with additional spectral features Wilms et al 2006 Cyg x-1 Wilms et al 1999 GX 339-4

  30. Spectral correlations • Cyg X-1 shows the a spectral index - intensity relation in the low state as do many AGN do. However the sign of the effect depends on energy and object

  31. Softer when Brighter-AGN The trend(with exceptions) for AGN : spectral index increase when the source is brighter in the 2-10 kev band Gliozzi et al 2004- 3c 390.3 Lamer et al 2003- NGC 4051 Markowitz and Edelson 2004

  32. Spectral Index Correlations in AGN • There is little relationship between x-ray spectral index and optical properties for broad line objects • There may be a correlation with Eddington ratio • Redshift dependance ? - (Chartas)

  33. Indirect Imaging of Black Holes Using Spectroscopic De-convolution Deconvolved image from ASCA line profile • ASCA discovered a relativistically broadened iron line that come from close to the event horizon of black holes in the nucleus of nearby galaxies • This feature also occurs in GBHs - but so far not in ULXs • This line provides a unique probe of the inner sanctum near black holes, observing the effects of GR in the strong gravity limit • Recent results have show not only emission but absorption

  34. Relativistic lines in Galactic BHs Many galactic black holes,often show broad Fe K lines - Jon Miller

  35. XMM AGN Fe K line profiles- Reeves et al NGC4151, Fairall 9 Mrk335 NGC7213 NGC4151 NGC7213 MKN335 * EW=206 Fairall 9 *

  36. XMM Fe K line profilesIIZW2, NGC7469, Mrk 841, NGC3227 IIIZw2 NGC7469 MKN841 NGC3227

  37. While many BHs have Broad lines- so do some NS (Asai et al 2001) However it is not common and in general EW of Fe K emission is low and the line widths are narrower then found in AGN and GBHs The variety of line shapes and physical effects thus make a broad Fe K line not unique to BHs Fe K lines In Neutron stars

  38. J. Miller et al 2004,2005

  39. However there is not yet a detailed1:1 comparison of the Fe K line shapes in AGN and GBHs J. Miller et al 2004,2005

  40. There is a very wide range of accretion rates in AGN • Based on SDSS [OIII] data there is a very wide range of Eddington ratios in AGN • We now need work on connecting the SED and x-ray spectra to the Eddington rate • So far there seem to be only subtle effects - more work needed Heckman 2004)

  41. ‘Unification’ of Black holes Whole meetings have been devoted to this subject but is is fair to say that there are strong resemblances in the both the photon spectra of AGN and GBHcs in the low state and between the PDS in AGN and GBHs SUPERUNIFICATION OF ACTIVE GALACTIC NUCLEI:Black Hole Mass, Spin and Accretion RateElba Island (Italy), May 25-28, 2005

  42. Radio, X-ray and Mass • There is an apparent relation between the radio and x-ray luminosity and the mass of the black hole. • Unfortunately I do not have time to discuss the radio emission - see Markoff et al Merloni 2005 3 orders of magnitude

  43. Absorption features AGN MCG-6-30-15 Young et al 2006 • Both AGN and GBHcs (but so far not ULXs ? NGC1313 Makishima) show Fe in absorption as well • However these features are also seen in neutron star binaries and thus are indications of winds and ionized material and not a black hole signature

  44. GBH

  45. Resonant Abs Lines • Low velocity resonant abs lines from a wide variety of ionization stages are seen in both GBHs, AGN and NS • Associated with winds • Probably not line, thermal or radiation driven wind, so magnetic from inner disc? Suzaku data for GBH (4U1630 Kubota et al 2006 v~1000km/sec

  46. High Velocity Resonant Abs Lines PG1211- blue shifted resonance Fe absorption feature V~0.08c (Reeves et al 2003) • So far high velocity Fe abs lines have only been reported In AGN (Pounds et al 2003, Reeves et al) PG1211+143 etc Pounds • If this is more general it implies that AGN winds can carry a large amount of energy- so far not yet seen in GBHs or ULXs PG1211 Chandra LETG data- If features are Fe v ~0.26, 0.4c

  47. AGN High Velocity Lines MR2251-17 Highly blue shifted feature V=12,700km/sec • There are now several other examples of high velocity blue shifted Fe absorption lines in AGN • These indicate a fast wind with a mass flow rate greater than the accretion rate. • If this is a general BH phenomenon have a strong influcence on galaxy formation, ISM and IGM 1.75 1.8 1.85 1.9 Wavelength (A) Gibson et al 2005

  48. Power Density Spectra NGC3516 Nandra and Edelson • power density spectra , for many galactic black holes and AGB are flat at low frequencies steep at high frequencies • This form seems to be ‘ubiquitous’ in black holes (not seen in high state GBHs) • The break frequency scaling as mass of object Hayashida et al Black hole mass NGC4559 x-7 Break timescale days

  49. How is Time Variability Characteristics Related to Mass • Measurement of the break frequency in the PDS seems to be related to the black hole mass. • However the shape of the PDS in galactic black holes depends on state: • Not clear if this applies to AGN or not • Situation for ULXs is unclear since only 2-3 breaks in the PDS have been measured

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