Marco Salvati

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Marco Salvati
INAF (Istituto Nazionale di Astrofisica)? Osserv
atorio Astrofisico di Arcetri
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Black holes and revelations two or three
revelations we are still missing
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orThe seven pillars of wisdom
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or We need one more to open the eightfold path
to enlightenment
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• The core of the engine is a supermassive black
  hole
• now it seems trivial, but
• spinars, ensemble of pulsars or SNe, quark
  factories
• (a BH to stabilize a spinar, some Liners could be
  ensembles of stellar objects)

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Rees, ARAA 22 (1984) Black hole models for
AGNs Note the s appears in the original !
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2. Bondi accretion is inefficient, you need a
disk (stable, ie non self-gravitating) At the
beginning there was Shakura Sunyaev, then came
warped disks, 2T disks, coronae above disks, ion
supported tori, Adafs, Adios
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Pringle, ARAA 19 (1981) Accretion discs in
astro physics Note Lynden-Bell (1969), SS
(1973)
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3. Jets are not oddities (eg, M87) they are a
basic ingredient amenable to simple equations
How Blandford Rees jet paper was announced in
Erice in lieu of the sheduled lecture on
something entirely different (maybe globular
clusters !?)
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BR MNRAS 169 (1974) A twin-exhaust model for
double radio sources
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4. Finding the right radiation process(es) From
jets to magnetic fields to excessive faith in non
thermal processes playing with beach balls,
hiding a blazar inside NGC4151
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in filamentsonly a few metres across
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Salvati, unpublished and lost forever
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4. cont.d The disk-plus-corona model One of the
several instances of the generalized
equipartition assumption see also the gain
equal losses approach in blazar models
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Haardt Maraschi ApJ 413 (1993) Xray spectra
from two-phase accretion disks
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5. Unification Unification came in two main
flavors for radio quiet AGN (Antonucci Miller
1985), and for radio loud, jetted AGN (Barthel
1989, not so much radio galaxies vs radio
quasars, rather blazars vs non blazars)
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6. BH spin and radio loudness What is the
parameter deciding the radio loudness, ie, the
formation of a jet ? (btw, why jets and radio
loudness go together ?) The key issue here is the
high required efficiency
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6. cont.d Blandford Znajek (1977) Jets can be
more powerful than disks, hence magnetic braking
AND maximal rotation Additional evidence core vs
power law profiles, and mass bias of radio loud
galaxies (Capetti Balmaverde 2006)
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7. Integral constraints Soltan (1982), total AGN
light vs relic BH mass density in the local
Universe CXRB (more precisely, HXRB from SXR
counts AND unification)
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Setti Woltjer (1979)
Comastri et al. (1995)
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8. BH mass galaxy bulge relations, coevolution,
feedback, etc This is FAR from settled we can
claim seven pillars with some confidence, but
not eight yet for instance, what if indeed BH
mass grows first at high z ?
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Two stones of the mosaic -low luminosity AGN
from low mass black holes -low luminosity AGN
from high mass black holes
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LLAGN are (almost always) Liners, ie (almost
certainly) ADAF-like (no absorption) They
appear to continue smoothly the AGN
sequence They are too numerous to reside only in
massive bulges, ie their typical BHs have low
masses
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But consider the 3C catalogue, and plot the Xray
vs the high frequency radio luminosity at the
high end, both come from a boosted jet then the
Xrays are dominated by the isotropic disk at the
low end, only the jet is there (no visible
accretion a super-ADAF state ?)
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