Gas Dynamics in Galactic Nuclei:

1
Gas Dynamics in Galactic Nuclei Starbursts
and AGN Fueling Eliot Quataert (UC Berkeley) w/
Norm Murray Todd Thompson
Arp 220 w/ HST
NGC 6240 w/ Chandra
2
Outline

• Observational Context Ultraluminous Infrared
  Galaxies
• Eddington-Limited Starbursts
• From the Starburst to the Central AGN ( Back
  Again)
• Conclusions Future Work

3
Ultraluminous Infrared Galaxies (ULIRGs)

• Discovered by IRAS in mid 80s
• LFIR gt 1012 L? gtgt Loptical (dusty)
• Disturbed Morphologies Mergers
• Powered by nuclear starbursts /or obscured AGN
  (much debated)

4
Ultraluminous Infrared Galaxies (ULIRGs)
Josh Barnes

• Discovered by IRAS in mid 80s
• LFIR gt 1012 L? gtgt Loptical (dusty)
• Disturbed Morphologies Mergers
• Powered by nuclear starbursts /or obscured AGN
  (much debated)

also Mihos Hernquist 1996
Mergers ? Angular Momentum Transport ? Nuclear
Activity
5
Ultraluminous Infrared Galaxies (ULIRGs)

• High z analogues discovered in abundance in submm
  surveys (SCUBA/MAMBO)
• Highly obscurbed objects account for a
  significant fraction of star formation at z few
• Key Phase in Growth of Elliptical Galaxies and
  Massive BHs?

Chapman et al. 2004
(e.g., Sanders et al. 1988 Kormendy Sanders
1992)
6
Physical Conditions Arp 220
HST Nicmos Image
LFIR 1012 L? Double Nuclei 350 pc apart 2
100 pc scale disks with 109 M? gas
( circumbinary disk) ?gas 10 g/cm2 4000
?MW (optically thick to FIR) ltngt
104 cm-3 vs. ltngtMW 1 cm-3
Sakamoto et al. 1999
7
Physical Conditions Arp 220
Radio Emission on FIR-Radio Correlation
Radio SN ? 100 pc scale starbursts with 100
M?/yr
Condon et al. 1991
Individual Radio SN detected w/ VLBI
1 350 pc
Smith, Lonsdale, Diamond
8
The Case For Radiation Pressure
?, Teff
Hydro Equil P ?G?2 Pressure supplied by star
formation (probably) (e.g., in normal galaxies,
SN, stellar winds, HII regions, )
9
Phydro ?G?2
The Schmidt Law

• For sufficiently large ?,
• Prad ? Phydro the disk
• reaches the Eddington limit
• (and the Schmidt Law breaks down)
• ? 3 g/cm2
• (the inner few 100 pc
• of gas-rich starbursts)

SFR
Kennicutt 1998
?gas
10
Radiation Pressure vs. Supernovae
SN stirring radiative losses are strong, but
each SN supplies a momentum ? Mshvsh
to the ISM
Salpeter IMF assuming all SN add constructively
(optimistic) ?
Radiation Pressure Dominates SN for Optically
Thick Starbursts (the inner few 100 pc of
gas-rich starbursts)
11
Eddington-Limited Starbursts
?, F
12
Opacity
Dust Opacity (T lt 103 K)
13
Eddington-Limited Starbursts
?, F
14
Radio Sizes of ULIRGs 100s pc

• Condon et al. 1991

15
Number of ULIRGs vs. Inferred Flux
16
Inward Bound Towards the Central BH

• Inflow vs. Star Formation Fueling a Central AGN
  Requires tinflow lt t
• Canonical AGN Disks (e.g., Shakura Sunyaev) are
  Gravitationally Unstable, with Toomres Q ltlt 1
  outside 0.01-0.1 pc
• Hypothesis Star Formation Supports the Disk
  Maintains Q 1
• tinflow lt t requires
• Low Star Formation Efficiency (lt 0.1 on pc
  scales)
• Efficient Angular Momentum Transport (spiral
  waves, bars, winds, etc.)

17

• Local Disk Model
• Q 1
• P Prad PSN
• (Schmidt Eddington)

Gas Fraction 0.3
Gas Fraction 0.1
Star Formation Efficiency (t?)-1
Gas Surface Density
18
Masing Disks

• Q 1 P Prad ?
• Similar to conditions required for H2O Masers (n
  108-1011 T 500 K),
• which are observed on 0.1-1 pc scales in
  several local AGN
• (e.g., NGC 1068 3079)

19

• Global Disk Model
• Q 1
• P PradPSNPgas
• (Schmidt Eddington)
• viscous stress
• (vR 0.1 cs global torque)
• 4.

Accretion Rate
Star Formation Rate
MBH 109 M?
20

• Global Disk Model
• Q 1
• P PradPSNPgas
• (Schmidt Eddington)
• viscous stress
• (vR 0.1 cs global torque)
• 4.

Accretion Rate
Star Formation Rate
MBH 109 M?
21
Starburst
Reprocessing?
AGN
PREDICTIONS A non-negligible fraction of the FIR
emission in luminous AGN is from star formation
(which is required to stabilize the gas at large
radii) More luminous (gas-rich) systems should
preferentially host AGN (true for ULIRGs)
FIR
UV
22
Thickness of the Disk
Midplane Scale-height H/R cs/vrot
23
Vertical Structure on pc Scales

• Photosphere is extended
• well off the midplane
• F FEDD ?2cz/?
• ?ph gt ?mid
• Nuclear Obscuration
• (for luminous AGN)?

24
Vertical Thickness of the Disk
Photospheric H/R
Hph R at few pc
25
NGC 1068 300-800 K dust is resolved with
VLT interferometry on few pc scales
Jaffe et al. 2004
26
Feedback from the Central AGN
M(r) 2?2r/G Mg fM
For L gt LM momentum injection is sufficient to
blow away all of the gas in a galaxy
Conjecture LM is an upper limit to the
luminosity of an AGN (or
starburst) systems that reach LM
self-regulate L does not increase further
27
The Maximum Luminosity of Quasars
? from width of OIII line in NLR
28
Gas Dynamics in Galactic Nuclei

• Eddington-Limited Starbursts in the Inner 100
  pc of Galactic Nuclei
• Good Agreement w/ ULIRGS
• AGN Fueling tinflow lt t requires rapid
  inflow inefficient star formation
  plausible models allow AGN to outshine starburst
• Global Disk Models Nuclear Obscuration via the
  Disks Atmosphere
• LM 3x1046 (?/200)4 ergs/s maximum luminosity
  of BHs
• LBH LM ? MBH-? relation observed in local
  galaxies

29
Future Work

• The Multiphase ISM from 0.1-100 pc
• radiation pressure dominated molecular clouds,
  the intercloud medium,
• Efficacy of Gravitational Torques at 1-10 pc
• Masing Disks
• Radiation Hydro Simulations of BH Feedback
• Radiation Pressure Impt. in Local Star-Forming
  Regions?