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Supermassive Black Holes

Supermassive Black Holes. Course 689 Presentation by Yan Shi Nov 5, 2009. A Fundamental Relation Between Supermassive Black Holes and their host Galaxies 1 Laura Ferrarese, David Merritt (Published August 2000) Beyond the Bulge: A Fundamental Relation Between

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Supermassive Black Holes

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  1. Supermassive Black Holes Course 689 Presentation by Yan Shi Nov 5, 2009

  2. A Fundamental Relation Between Supermassive Black Holes and their host Galaxies1 Laura Ferrarese, David Merritt (Published August 2000) Beyond the Bulge: A Fundamental Relation Between Supermassive Black Holes and Dark Matter Halos Laura Ferrarese (Published October 2002) Note 1: 1501 citations to date

  3. Outline of the Presentation • MBH and σc relation (Ferrarese & Merritt 2000) • MBH and MDM relation (Ferrarese 2002) • MBH and Mtot relation using gravitational lensing data (Bandara et al 2009) • Possible explanations ofMBH– Mtot relation σc : Velocity dispersion at central bulge MDM ≈ Mtot

  4. MBH versus Bulge Central Velocity Dispersion (Ferrarese & Merritt 2000) • First study of the relation between MBH and the stellar velocity dispersion of the host galaxy. • Two group samples of galaxies: • Group A: Reliable MBH estimates including MW , NGC 4525, and 10 galaxies from HST observations. • Group B: Less accurate MBHdata from ground based observations of stellar kinematics. MW : motion of stars in Sagittarius A NGC 4525 : water maser

  5. Correlation between MBH and Bulge Central Velocity Dispersion σc Sample A (reliable data) Sample A (reliable data) MBH versus σc (Right) MBH versus Bulge Absolute Blue Luminosity (Left) Sample B Sample B Strong MBH - σc correlation; weaker MBH - luminosity correlation. Indication of stronger relation with Mtot not just baryons.

  6. Strong Correlation between MBH and Vrms (Vrms measured at re/4) MBH versus Vrms (open circles, dashed line). MBH versus Bulge Central Velocity Dispersion (filled circles, solid line) Since R(Vrms)  RBH , the MBH – Vrms relation is not caused by the influence of the BH on stellar kinematics. re : effective radius, include half image light

  7. Circular velocity Vc - σc Relation (Ferrarese June,2002) Vc is measured beyond R25 where the rotation curve is flat. R(Vc) > R(Vrms)  R(σc ) Vc is determined by MDM The Vc - σc Relation provides the link between MBH and MDM .

  8. The MBH and MDM Relation (Ferrarese June,2002) The MBH - MDM Relation is obtained by converting Vc into MDM .

  9. The MBH– Mtot Relation by Gravitational Lensing (Bandara et al 2009) Ferrarese 2002 Bandara et al 2009 Gravitational lensing provides a more robust method to determine Mtot . No conversion of velocity to mass required.

  10. How does the entire galaxy know what is the mass of the BH at the center?

  11. Possible Explanation : Building Blocks Idea • The first objects formed in the universe were not stars. • Larger number of identical building blocks merged and formed into a galaxy. They provided seed black holes to coalesce into a single, massive black hole in the center of the galaxy. . . . = + + Richstone et al, 1997, 189th Meeting of the American Astronomical Society. Can explain the MBH– Mtot relation. Need to explain how the identical building blocks were formed.

  12. Possible Explanation : Quasar, AGN Idea • Radiation from the accretion disk applies pressure to the in-falling particles. • Silk & Rees 1998 and king 2003 were able to calculate σc for a given BH mass. MBH σc5 (Silk & Rees) MBH σc4 (King) Obtain the MBH– σc relation, not the MBH– Mtot relation.

  13. An Engineer’s view : Servo loop • In order to build theMBH– Mtot relation need to have • Communications (between BH and rest of the system) • Feedback (able to add or reduce mass from the BH) There is no efficient way to remove matter from a BH. The Servo Loop idea does not work.

  14. Summary • Ferrarese & Merritt 2000 was the pioneer work to point out the MBH - σc relation. • The relation was expanded to link with Mtot by Ferrarese in 2002. • More observations including gravitational lensing confirm the MBH– Mtot relation. • There is no satisfactory explanation of the relation other than observations as of today. MBH– σc– Vrms – Vc – Mtot

  15. Backup Slides

  16. More Results on MBH and Velocity Dispersion Relation Tremaine April,2002

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