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Galactic Environment of Nearby Quiescent Supermassive Black Holes

Galactic Environment of Nearby Quiescent Supermassive Black Holes. Q. Daniel Wang University of Massachusetts. SMBH and bulge mass correlation. SMBH and galaxy formation are closely related. Every galaxy probably contains a SMBH. Their masses are correlated.

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Galactic Environment of Nearby Quiescent Supermassive Black Holes

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  1. Galactic Environment of Nearby Quiescent Supermassive Black Holes Q. Daniel Wang University of Massachusetts

  2. SMBH and bulge mass correlation SMBH and galaxy formation are closely related • Every galaxy probably contains a SMBH. • Their masses are correlated. • Physically, how this correlation is achieved is not clear. • The SMBH growth is largely from gas accretion  AGNs

  3. But most of SMBHs are not active in nearby galaxies. They are starved. Why? • Little gas falls into the galaxy center? • Or the infalling gas is being removed, due to episodic AGN feedback or some continuous processes? Answering these questions will help to understand the formation of SMBHs and galaxies in general.

  4. IRAC 8 micro 0.5-2 keV 2-8 keV Li & Wang 2007 M31 (d=780 kpc)

  5. GALEX far-UV excess vs. Hα

  6. M31*: SMBH and its vicinity • A red star cluster forming an elongated disk (Tremaine 1995) • Mbh ~ 2 x 108 Msun (Bender et al. 2005) • Apparent young (A-type) stars (t ~ 200 Myr) around the SMBH • Alternatively, they may be post-HB stars formed from stripped redgiants and/or stellar mergers (e.g., Demargue & Virani 2007). P1 P3 (M31*) P2

  7. Chandra/ACIS limit on the X-ray luminosity of M31* • Lx ~ 1(+-0.3)x1036 erg/s, consistent with the previous 3 upper limit from a Chandra/HRC (Garcia et al. 2005) • kT ~ 0.3 keV • n ~ 0.1 cm-3 • Rb ~ 0.9”, Lb ~ 3x1040 erg/s P1 M31* SSS Chandra/ACIS 0.5-8 keV vs. HST/ACS (F330W)

  8. Chandra/ACIS source detection With 1’ radius: • Lx > 1036 erg/s: an enhanced number density  dynamic formation • 1036 > Lx > 1035: a deficit  destruction of loosely bound LMXB?

  9. Unresolved emission along the major-axis Lx < 1035: : below the detection limit: • CVs and active stars • hard (2-8 keV) emission follows the near-IR light: a stellar origin • soft (0.5-2 keV) emission only follows the near-IR light at large radii; excess in the inner bulge  diffuse gas 0.5-1(2-8) keV; along major-axis

  10. Diffuse soft X-ray emission • stellar contribution subtracted • characteristics of hot gas in the bulge: • z0 ~ 600 pc; • T~ 0.3 keV; • L0.5-2 keV ~ 31038 erg/s IRAC 8 micro, K-band, 0.5-2 keV

  11. Diffuse emission along the minor axis • X-ray shadows of spiral arms: extraplanar hot gas with a height > 2.5 kpc 0.5-1(1-2) keV; along minor-axis

  12. Galactic bulge simulation • Parallel, adaptive mesh refinement FLASH code • Finest refinement in one octant down to 6 pc • Stellar mass injection and SNe, following stellar light • SN rate ~ 4x10-4 /yr • Mass injection rate ~0.1 Msun/yr) 10x10x10 kpc3 box density distribution

  13. Galactic Bulge Wind: Simulation • Radiative cooling is not important in the bulge region, consistent with the observation • Energy not dissipated locally • Most of the energy is in the bulk motion and in waves • The wind solution does depend on the outer boundary condition! 3x3x3 kpc3 box, density distribution

  14. 0.5-2 keV diffuse X-ray vs. Spitzer MIPS 24 μm

  15. The Milky Way

  16. ~ 1055 erg, or > 104 SNe is needed over the past 2 x 107 years!

  17. ROSAT Survey (1.5-keV Band)

  18. Chandra survey of the Galactic center Wang et al. (2002)

  19. Arches GC Quintuplet Massive star forming region: Composite Chandra map • Chandra Intensity: • 1-4 keV • 4-6 keV • 4-9 keV Wang, Hui, & Lang (2006)

  20. X-ray Flare from Sgr A* • Peak L(2-10 keV) 1035 erg s-1 • Lasted for about 3 hrs • Variability ~ a few minutes But the observed Lx is ~10-4 of the expected! Baganoff et al. (2003)

  21. Diffuse X-ray Spectrum Decomposed into three components: • CVs with T ~ 108 K • Hot gas with T ~ 107K • Nonthermal: inverse Compton scattering, bremstrahlung, and reflection Hui & Wang 2008

  22. Imaging decomposition CV Hot gas nonthermal absorption

  23. Hot gas vs. radio continuum

  24. Comparison with other extended X-ray-emitting features Sgr A* PWN IRS 13 Diffuse The spectra of Sgr A*, IRS 13, and diffuse X-ray emission all show the Fe K line at ~6.6 keV  NEI emission from gas heated recently (net~103 cm-3 yr).

  25. VLA 20cm Spitzer 8m Spitzer 3.6m Great Observatory mapping of the GC Ongoing: 1) Deep Chandra Survey, 2) HST/NICMOS mapping of NIR continuum and Paschen- line emission (32’x13’, 144 orbits) VLA 20cm Spitzer 8 m 1-9 keV

  26. Conclusions • Cool gas is expected to fall into nuclear regions of disk galaxies. • The gas can be heated, however, responsible for excess of far-UV and Halpha emission as well as mass-loading to hot gas • The heating may be due to steepening ofSN waves. • The mass-loaded gas can produce subsonic outflows, consistent with X-ray observations: • moderate luminosity • low temperature • broad spatial distribution. • Stellar energy feedback in galactic bulges may lead to the starvation of SMBHs!

  27. CMZ T ≤107 K Filling factor? Composition? Physical properties? Heating and cooling? Mass loading?

  28. Magnetic loops Corona Galactic disk

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