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What do we know about accretion disk structure at R < 1 pc?

The Accretion Disk Structures Black Hole Masses and Cosmic Distances The New Radio Universe. Lincoln Greenhill (Harvard-Smithsonian CfA). What do we know about accretion disk structure at R < 1 pc? What do disks tell us about BHs and AGN? What do disks have to do with distances?.

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What do we know about accretion disk structure at R < 1 pc?

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  1. The Accretion Disk StructuresBlack Hole Massesand Cosmic DistancesThe New Radio Universe Lincoln Greenhill (Harvard-Smithsonian CfA) • What do we know about accretion disk structure at R < 1 pc? • What do disks tell us about BHs and AGN? • What do disks have to do with distances?

  2. Accretion Disks in Seyferts • What has been seen (by “conventional means”)? • Images of kpc circumnuclear rings • Images of disks (tori?) at R=100 pc • Spectra of ionized gas @ 3-10 RSch • What is missing from this list? • Images of structures firmly within Rg, • the SMBH sphere of influence, R < 1 pc. • (Regions for which Av= 100s or 1000s) Weigh IC Define pole Measure mdot Do you want to Talk about what Msr/disk can do OR The disks are representatives Of the environs - what we Can learn about the disks?

  3. Investigating sub-pc Disks The goal: actual images The means: • X-ray irradiation heats gas • Dense regions self-shield, molecules form • In trace H2O, heating stimulates MASER emission … and as seen time and again … • Masers inspire radio astronomers to pursue VLBI

  4. Exotic sounding but pedestrian in fact • Masers trace “hotspots” in underlying structures • Compact (q < 1 mas) • High surface brightness (TB ~ 107 -1015 K) • Yield qx, qy, Vlos, qx, qy, d[Vlos]/d[los] . . H2O Maser Precis • Particular conditions required • Dense (108 - 1010 cm-3) • Warm (300 - 800 K) • Quiescent (Dv ~ DvD)

  5. What do the spectra look like? The most interesting show (symmetrically) offset high-velocity lines This is what fore-warns of a disk, approaching & receding material. •

  6. What do the disks look like? • Warped • Thin • Keplerian - or nearly so • Aligned w/ outflows - marking SMBH axes • In the way... • Obscuring the SMBHs • Channeling outflows

  7. Archetypal Emission Map ~0.001 NGC4258 Emission Spectrum (H2O) What is this? Cecil et al. 2000

  8. Kagoya/Inoue Review a Accretion Disk & Black hole mass: Miyoshi et al. 95 Jet @ 4000Rs: Herrnstein et al. 97 Accelerations: Nakai et al. 95 Greenhill et al. 95 Bragg et al. 00 Distance±7%: Herrnstein et al. 99 . q The NGC4258 Disk • Warped (a few °) • Thin (< 1%) • Aligned (a few °) • Indicator of mass •

  9. Kagoya/Inoue Cannizzo, Smith et al. Fx(2-10 kev) NH 1 yr • Where is the obscurer? • No torus known (R»Rdisk) • Yet C.E. is just 0.1Rin above the disk XTE monitoring (see also Maloney 1999; Reynolds et al. 2000) • disk ~ obscuration •

  10. Warped accretion disks rather than tori may account for X-ray absorbing columns in some systems.Speculation: Sub-pc warped disks may also dictate the pattern of photoionization in the NLR on kpc scales.

  11. Consider the Circinus galaxy... H I Jones et al. (1999) Veilleux & Bland-Hawthorne (1997) Greenhill et al. (2001,2003) •

  12. Keplerian Envelope Outflow • The inferred disk warp • Imposes a shadow • And constrains flow & illum. • In Circinus, conditions • support H2O masers in • an edge-on accretion disk • a nuclear outflow

  13. In Seyferts, sub-parsec warped disks can regulate appearances Veilleux & Bland-Hawthorne (1997) Greenhill et al. 2003 •

  14. Observe vlos -1/2 vlos2  M/Ds dvlos/d [M/Df3]1/2 s f f alos  v2/Df D M or  ~ vt/D  (M/D)1/2/Df1/2 . M D From here, how do we estimate D? M/D

  15. Observe vlos -1/2 vlos2  M/Ds dvlos/d [M/Df3]1/2 NGC4258 Mbh ~ 3.9x107 Msun D ~ 7.2 Mpc (7%) f alos  v2/Df D M or  ~ vt/D  (M/D)1/2/Df1/2 . M D From here, how do we estimate D? M/D • Promising systems: • NGC1068 Circinus • IC2560 NGC2639 • NGC5793 Braatz-1 • Tid-2

  16. The Future is Now ...

  17. Known H2O Masers in AGN Mpc Jy VLBI thin disk, possible disk, jet/possible jet, VLBI nondetection,VLBI detection.

  18. A New Generation of Surveys Designed to detect perhaps the most interesting disks, high-velocity disks Effelsberg Madrid DSN Tidbinbilla DSN GBT •

  19. A New Generation of Surveys A new high-velocity disk Discovered: Tidbinbilla 2002 June 1 •

  20. The Future is... • Detailed study of accretion disk geometry • and its role in shaping AGN • Precision black hole mass estimates • Geometric distances to nearby AGN • and, of couse, • More H2O masers

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