What Happens Close to a Black Hole ?

1. ‘Symposium on High Energy Astrophysics’ HRI, Feb 18, 2012 What Happens Close to a Black Hole ? We don’t know A. R. Rao, TIFR, Mumbai

2. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

3. Black Holes • Stellar Structure theory • Dynamical mass measurements: compact stars heavier than a few solar masses • A massive object at the center of our galaxy • Active Galactic Nuclei • Ultra-luminous X-ray (ULX) sources • Gamma-ray bursts

4. Force equation: • Radiation pressure and gas pressure. “I do not see how a star which has once got into this compressed state is ever going to get out of it ... It would seem that the star will be in an awkward predicament when its supply of subatomic energy fails.” –Sir Arthur Eddington Chandrasekhar limit

5. Stellar mass Black Holes • Compact objects heavier than neutron stars/ white dwarfs • Mass function f(M) = P K3 / 2  G = M sin³i / (1 + q)² • Cyg X-1: P = 5.6 d • M2 > 9 M (~30 M) • Last 15 years: several new sources : transients

6. Some statistics 20 black hole binaries known 10% of X-ray Binaries 17 transient LM-XRB (3 always bright) 0.17 - 33.5 days 13 radio bright (5 jets) 300 million estimated 5% of baryonic mass • Lightest known black hole: GRO J1655-40 M = (5.8 – 6.8 M) (95% confidence limit) • Most massive: IC 10 X-1: 33+3 M(> 21 M)

7. A Black Hole in the centre of our Galaxy 2.9 million x mass of the Sun Doelman et al. 08

8. Active Galactic Nuclei • Dynamical centers of some galaxies • Large lumonisity in tiny spaces • Powerful sources at all wavelengths • - strong continuum • – X-ray emission most generic property • Seyfert 1 and Seyfert 2 galaxies, NLS1s, • QSOs, LINERs etc • BLRGs, NLRGs, BL Lac objects, Blazars etc

9. Reverberation mapping Peterson (1997) • Broad Line region: 0.01 - 1pc; Illuminated by the AGN's photoionizing continuum radiation and reprocess it into emission lines • RBLR =c  t • V estimatedby the FWHM of broad emission line • - M = f (rV 2 /G)

10. Mass from optical emission lines in M 87 • M=2.4 109 M Macchetto et al. (1997)

11. Mass from maser observations • 22 GHz microwave emission • NGC 4258 M=4 107M Miyoshi et al. (1995)

12. Black Hole Census • Two dozen dynamical mass measurements of Stellar mass black holes • Five dozen super-massive black holes (reverberation mapping, stellar/gas dynamics, water maser) • Another two dozen stellar mass and a several thousand AGN from correlations and scaling laws.

13. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

14. Accretion onto Black Holes • Rs = 2 GM/c² = 3 km M/ M • ISCO = 3 Rs ; 2200 Hz (Rs/2) •  = 0.057 – 0.42 • Accretion (angular mtm Transport) driven by MHD turbulence • Can support B-fields that thread the black hole (stretched) horizon

15. Spectral states Rs = 2 GM/c² = 3 km M/M ISCO = 3 Rs ; 2200 Hz (Rs/2)  = 0.057 – 0.42

18. AGN X-ray spectrum

19. Broad Iron fluorescence lines Iron line profile in MCG-6-30-15 (Tanaka et al. 1995) Galactic: Miller 2007

20. Inner radius BH spin Spin measurement by Blackbody Spectral fitting Narayan & McClintock L  T4

21. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

22. GRS 1915+105: A Micro-quasar • Proper motions: • µa = 17.6 ± 0.4, µr = 9.0 ± 0.1 mas d-1 • From line of sight HI absorption • D = 12.5 ± 1.5 kpc • Apparent velocities on the plane of sky • 1.25±0.15 c and 0.65±0.08 c • True speed of ejecta  = 0.92 ± 0.08 • Jet angle  = 70o ± 2o to the of sight • 1997 observations show higher proper motions  smaller distance and angle VLA observations Mirabel & Rodriguez 1994, Nature, 371, 46

23. Definite pattern of jet activity seen as a function of spectral state (Fender et al. 2004) Spectral States and Jets Fender, Belloni & Gallo (2004)

24. X-ray Radio correlation in Galactic Black Hole Sources (Brocksopp et al. 99; Corbel et al. 00; Gallo et al. 02; Markoff et al. 02) Gallo et al. 2003 Black Holes: The power behind the scene

25. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

26. Quasars/ micro-quasars

27. Variability, Luminosity & Mass of Black Holes • McHardy et al. 2006, Nature, 444, 730 • TB : MBH2 / Lbol Arevalo et al. 2008

28. QPO in AGNs RE J1034+396: Gierlinski et al. 2008

29. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

30. Mass measurements available for 39 AGNs and 17 XRBs. • Typical accuracy • ~ 30% for AGNs • ~ 10% for XRBs

31. Black hole mass measurements Spectrum Lx/ LEdd Radio Timing

32. Accretion onto Black holes Observers can define a ``small number of states and their association with jets providing a good frame work to base theoretical studies'‘ (Belloni et al, 2011, arxiv1109.3388 Theorists, claiming that there is remarkable success in the study of black hole accretion disks, lament that the most pressing problem of the day is to match ``our theretical knowledge to actual observed phenomena'' (Abramowicz \& Fragile, arxiv1104.5400) ``We are still a long way From a theory of accretion Discs with real predictive Power’’ – King, arXiv1201.2060

33. Cyg X-1 hard: disk (scattered) Compt. ReflectionCyg X-1 soft: non-thermal ComptXTE J1550-564: VHS/IS

34. RXTE-PCA HEXTE OSSE GRS 1915+105

35. dN/dE = E- Photons/cm2/s/keV E*E-  keV/cm2/s/keV (cm2/s) E² * E- keV(keV/cm2/s/keV)

36. Abs*(diskbb+cpompST)

37. Wide band spectrum of a black hole candidate

38. EQPair: Zdziarski et al.

39. Eqpair for multiple sources GRS 1915+105 Crab Cyg X-3

41. Plan • Black Holes in the Universe • Accretion theory • Disks, Jets and outflows • Across Mass scales • The difficulties • The Astrosat project • Conclusions

42. ASTROSAT SXT UVIT LAXPC CZT SSM

43. Astrosat Instruments 1.LAXPC : Large Area X-ray Proportional Counters; Aeff ≈6000 cm2; FOV =10 X 10; 3-80 keV; E/ΔE ≈ 5 to 12. 2. CZT Imager: Cadmium-Zinc-Telluride array with Coded Aperture Mask; Aeff =500 cm2; FOV = 60 X 60;10 – 100 keV; E/ΔE ≈ 20 to 30. 3. SXT : Soft X-ray Telescope using conical-foil mirrors A eff ≈ 200 cm2 ; FOV = 0.50; (~3‘ res); 0.3-8 keV; E/ΔE ≈ 20 to 50. 4. SSM : Scanning Sky Monitor (SSM) with 3 PSPCs and coded aperture mask; A eff ≈ 30 cm2 (each); 2-20 keV. 5. UVIT : Ultraviolet Imaging Telescope (UVIT) two telescopes each with 38 cm aperture; near-uv , far-uv and visible bands.

44. Multi-wavelength studies (UV to X-rays) spectra, variability. Periodic and aperiodic variability. Broad band X-ray spectroscopy non-thermal components, cyclotron lines. Surveys All-sky, Galactic plane, deep. Astrosat Science Objectives…

45. Suzaku Vs CZT-Imager

46. Mrk 110

47. Binary X-ray Pulsars with Astrosat Simulated 10 ks observations of a hard X-ray pulsar spectrum. The cyclotron lines are nicely resolved by ASTROSAT .

48. Conclusions • The inner-most regions of the accretion disk in Black Hole sources are emitters of non-thermal radiation. • Precise hard X-ray continuum spectroscopy is needed to understand this region. • Implications for a variety of phenomena in high energy astrophysics: GRBs, accretion physics, AGN growth…. • Astrosat would be a small but decisive step forward.