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The Evolution of Super-Massive Black Holes

The Evolution of Super-Massive Black Holes. Ezequiel Treister (IfA, Hawaii ) Meg Urry, Priya Natarajan (Yale) Dave Sanders (IfA) Eric Gawiser (Rutgers). Credit: ESO/NASA, the AVO project and Paolo Padovani. Active Galactic Nuclei (AGN). Urry & Padovani, 1995. Black hole–galaxy connection.

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The Evolution of Super-Massive Black Holes

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  1. The Evolution of Super-Massive Black Holes Ezequiel Treister (IfA, Hawaii) Meg Urry, Priya Natarajan (Yale) Dave Sanders (IfA) Eric Gawiser (Rutgers) Credit: ESO/NASA, the AVO project and Paolo Padovani

  2. Active Galactic Nuclei (AGN) Urry & Padovani, 1995

  3. Black hole–galaxy connection All (massive) galaxies have black holes Tight correlation of MBH with  Common BH/SFR Evolution AGN feedback important

  4. All (Massive) Galaxieshave super-massive black holes

  5. Black hole–galaxy connection All (massive) galaxies have black holes Tight correlation of MBH with  Common BH/SFR Evolution AGN feedback important

  6. MBH-  Correlation Same relation for both active and non-active galaxies. Greene & Ho, 2006

  7. Black hole–galaxy connection All (massive) galaxies have black holes Tight correlation of MBH with  Common BH/SFR Evolution AGN feedback important

  8. Common BH/Star Formation Evolution Marconi et al. 2004

  9. Black hole–galaxy connection All (massive) galaxies have black holes Tight correlation of MBH with  Common BH/SFR Evolution AGN feedback important

  10. No AGN With AGN Feedback AGN Feedback Springel et al. 2005

  11. Supermassive Black Holes Many obscured by gas and dust • How do we know that? • Local AGN Unification • Explain Extragalactic X-ray “Background” Credit: ESO/NASA, the AVO project and Paolo Padovani

  12. Observed X-ray “Background” Frontera et al. (2006)

  13. AGN in X-rays Photoelectric absorption affect mostly low energy emission making the observed spectrum look harder. Increasing NH

  14. Compton Thick AGN • Defined as obscured sources with NH>1024 cm-2. • Very hard to find (even in X-rays). • Observed locally and needed to explain the X-ray background. • Number density highly uncertain. • May contribute significantly to SMBH accretion. • Multiwavelength observations are required to find them. • Hard X-rays (E>10keV) very useful locally.

  15. Swift INTEGRAL

  16. ISDC Swift Sources Tueller et al. 2007

  17. Deep INTEGRAL Survey (3 Msec) Significance Image, 20-50 keV

  18. Log N-Log S Treister et al. 2009

  19. Log N-Log S Treister et al. 2009

  20. Fraction of CT AGN X-ray background does not constrain density of CT AGN Treister et al. 2009

  21. X-Ray Background Synthesis Treister et al. 2009

  22. Contribution of CT AGN to the XRB Only 1% of the XRB comes from CT AGN at z≥2.  We can increase the # of CT AGN by ~10x and still fit the XRB. 50% 80% 90% Treister et al. 2009

  23. CT AGN at High Redshift Treister et al. 2009

  24. NuSTAR

  25. How to find high-z CT AGN NOW? X-rays Trace rest-frame higher energies at higher redshifts  Less affected by obscuration Tozzi et al. claimed to have found 14 CT AGN (reflection dominated) candidates in the CDFS. Polletta et al. (2006) report 5 CT QSOs (transmission dominated) in the SWIRE survey. Tozzi et al. 2006

  26. How to find high-z CT AGN NOW? Mid-IR X-ray Stacking F24/FR>1000 F24/FR<200 • 4 detection in X-ray stack. Hard spectral shape, harder than X-ray detected sources. • Good CT AGN candidates. • Similar results found by Daddi et al. (2007) Fiore et al. 2008

  27. Extended Chandra Deep Field-South Area: 0.3 deg2 X-rays: Chandra 250ks/pointing Optical: Broad band UBVRIz (V=26.5)+ 18 Medium band filters (to R=26) Near-IR: JHK to K=20 (Vega) Mid-IR: IRAC 3.6-8 microns + MIPS 24 microns to 35 µJy Spectroscopy: VLT/VIMOS, Magellan/IMACS (optical) VLT/SINFONI, Subaru/MOIRCS (near-IR)

  28. Mid-IR Selection • 211 sources with f24m/fR>1000 and R-K>4.5 • f24m>35Jy • 18 X-ray detected Log (f24µm/fR) R-K (Vega) Treister et al. ApJ submitted

  29. X-ray Undetected X-ray Detected All Sources Redshift Distribution • Photo-z for ~50% of the sources • X-ray sources brighter at all wavelengths • Spec-z for 3 X-ray sources and photo-z for 12 (83% complete). Treister et al. ApJ submitted

  30. Hardness Ratio  NH X-ray sources with redshift only • 2 unobscured • 11 obscured Compton-thin • 2 Compton Thick Assumed fixed =1.9 Treister et al. ApJ submitted

  31. Stacking of non-Xrays Sources Soft (0.5-2 keV) Hard (2-8 keV) • ~4 detection in each band. • fsoft=2.1x10-17erg cm-2s-1. Fhard= 8x10-17erg cm-2s-1 • Sources can be detected individually in ~10 Msec. • Hardness ratio 0.13, NH=1.8x1023cm-2. • Alternatively, ~90% CT AGN and 10% star-forming galaxies. • Some evidence for a flux dependence. >95% CT AGN at the brightest bin, 80% at the lowest. Large error bars. Treister et al. ApJ submitted

  32. Rest-Frame Stacking Good fit with either NH1023cm-2 or combination of CT AGN with star-forming galaxies. Consistent results with observed-frame stacking. Treister et al. ApJ submitted

  33. X-Ray to Mid-IR Ratio Both X-rays and 12µm good tracers of AGN activity. Observed ratios for X-ray sources consistent with local AGN (dashed line). Treister et al. ApJ submitted

  34. X-Ray to Mid-IR Ratio Effects of obscuration in X-ray band luminosity. Only important for Compton Thick sources. Treister et al. ApJ submitted

  35. X-Ray to Mid-IR Ratio ~100x lower ratio for X-ray undetected sources. Explained by NH~5x1024 to 1025cm-2 Treister et al. ApJ submitted

  36. X-Ray to Mid-IR Ratio Ratio for sources with L12µm>1043erg/s (~80% of the sources) ~2-3x higher than star-forming galaxies Treister et al. ApJ submitted

  37. X-Ray to Mid-IR Ratio Using Lx/L12µm=0.007 to separate AGN and star-forming galaxies  ~80% AGN, consistent with HR value. In sources with L12µm>1044erg/s outside selection region fraction of AGN ~10%. Treister et al. ApJ submitted

  38. Near to Mid-IR Colors • Distributions significantly different • X-ray detected sources much bluer • Average f8/f24=0.2 for X-ray sources and 0.04 for X-ray undetected sample Well explained by different viewing angle (30o vs 90o) in the same torus model Can it be star-formation versus AGN? Redder Bluer Treister et al. ApJ submitted

  39. Near to Mid-IR Colors ULIRG, LINER ULIRG, Sey2 Armus et al. 2007

  40. IRAC Colors AGN Faint 8 µm z>1 [3.6]-[4.5] (Vega) z=0-1 [5.8]-[8] (Vega) Treister et al. ApJ submitted

  41. Optical/Near-IR SED Fitting X-ray Undetected X-ray Detected • Median stellar mass for X-ray detected sources ~4.6x10-11 Msun. • For X-ray undetected source ~10-11 Msun. X-ray Detected • Mild extinction values found in general. • Maximum Av~4 mags. • Median E(B-V)=0.6 for X-ray detected sources and 0.4 for undetected ones. X-ray Undetected Treister et al. ApJ submitted

  42. CT AGN Space Density Number of sources roughly consistent with extrapolation of Compton-thin LF z=0 LF Steeper evolution suggested by Della Ceca et al. (2008) and Yencho et al. (2009) work better Treister et al. ApJ submitted

  43. CT AGN Space Density Systematic excess for Lx>1044erg/s sources relative to extrapolation of Compton-thin LF Strong evolution in number of sources from z=1.5 to 2.5. Consistent with heavily-obscured phase after merger? Treister et al. ApJ submitted

  44. SMBHs Spatial Density Accretion efficiency 10%

  45. UMBHs Spatial Density Natarajan & Treister, 2008

  46. UMBHs Spatial Density • Self-Regulation • Momentum-driven winds (Murray et al. 2004). • Radiation pressure (Haehnelt et al. 98) • Energy Driven Superwind (King 05) Natarajan & Treister, 2008

  47. Summary • Number of mildly CT sources at z~0 lower than expected. • Only ~1% of XRB comes from CT AGN at z~2. • Multiwalength surveys critical to find high-z CT AGN. • Mid-IR selection finds large number of CT AGN at z>1.5. Strong evolution in numbers up to z~3. • This could be evidence for a heavily obscured phase after quasar triggering. • Strong decrease in the number of UMBHs -> Self regulation process.

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