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Two distinct Accretion processes in radio galaxies

• Huub Röttgering
• Leiden Observatory

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• Big Question Coupled formation and evolution of
• Black holes / AGN
• Galaxies
• Large Scale Structure
• Some recent key results
• AGN Feedback deposits large amounts of energy
  influencing the evolution of clusters and
  galaxies
• Hierarchical clustering lead to most massive BH
  in the most massive galaxies which are in the
  most massive clusters
• zgt2 powerful radio galaxies are located in
  protoclusters
• (Overzier, Venemans, Kurk, Miley, de Breuk, van
  Breugel, Maschietto, van Breugel, Pentericci,
  Carilli, HR et al.)
• Spatially resolved observations of nearby tori
• Raban, Jaffe, Meiserheimer, Tristam, HR
• Radio loudness is a strong function of galaxy
  mass

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VLT interferometer observations with MIDI of NGC
1068
Correlated Flux density spectrum
UV plane
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Image of the torus of NGC 1068

• Two components
• Hot 800K, 1.4x0.5 pc
• funnel
• Cool 300K 3x4 pc
• torus
• Raban, Jaffe, HR,
• Meisenheimer, Tristam
• in prep.
• 9 other AGN show similar
• Structure, except the radio
• Galaxy CenA that does
• not seem to have a torus

8 micron image Box 6060 milli-arcs
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• Big Question Coupled formation and evolution of
• Black holes / AGN
• Galaxies
• Large Scale Structure
• Some recent key results
• AGN Feedback deposits large amounts of energy
  influencing the evolution of clusters and
  galaxies
• Hierarchical clustering lead to most massive BH
  in the most massive galaxies which are in the
  most massive clusters
• zgt2 powerful radio galaxies are located in
  protoclusters
• (Overzier, Venemans, Kurk, Miley, de Breuk, van
  Breugel, Maschietto, van Breugel, Pentericci,
  Carilli, HR et al.)
• Tori exist, but not in all AGN
• Raban, Jaffe, Meiserheimer, Tristam, HR
• Radio loudness is a strong function of galaxy
  mass

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For massive galaxies, the rate of activity and
energy output sufficient to heat their hot halos
(Best et al. 2005)
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Key questions

• How does the radio loud fraction evolve with z?
• How does the radio loud fraction depend on the
  environment?
• How does AGN activity depend on accretion mode ?
• Cold accretion / quasar mode / torus mode
• Activity due to a merging event
• Hot accretion / radio mode
• Activity due to hot gas cooling
• Topic of Cyril Tasses thesis
• Best, Cohen, Le Borgne, Pierre, HR, et al.

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XMM-LSS survey

• 10 sqr degree of XMM data
• Spitzer Swire survey
• CFHTLS (u,g,r,i,z) survey with 3 million galaxies
• GMRT and VLA surveys 74, 230, 325 and 610 MHz
• Complete catalogue with for each object
• Phot-z, galaxy mass, specific sfr, AGN loudness,
  density of its environment

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Evolution of the mass-fraction
A break appears at log(M/Mo) 10.5-10.8 Upturn
of the radio LF due to less massive galaxies
become more active
Fraction of galaxies that are radio loud
Z0 Log(P1.4)gt24 Z0 Log(P1.4)gt25
9.5 10.5
11.5 Log(M/Mo)
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450
450 kpc
Overdensity as a function of scale
250 kpc
75 kpc
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Difference in Density Radio source host and
normal galaxy
10.0 10.5 11.0 Log(M/Mo)

• Higher galaxy mass radio galaxies in clusters
• Lower galaxy mass radio galaxies are in pairs
• Cold accretion - due to merging more dominant at
  higher z ?
• The reason for the upturn in the radio LF?

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Delta IR
10.5 10.5
11 Log(M/Mo)

• Normalized IR excess for radio loud galaxies
• Only excess/torus emission for the lower mass
  galaxies

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Summary

• Radio galaxies with Log(M/Mo) gt 10.5
• Steep fraction-mass relation
• Located in overdensities of scale 450 kpc
• Do not have IR excess
• Identify with accretion of hot gas
• Radio galaxies with Log(M/Mo) lt 10.5
• Flatter fraction-mass relation
• located in overdensities of scales of 75 kpc
• Have an IR excess
• Identify with merging event driving cold gas to
  the center

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What about X-ray AGN?

• Similar analysis for
• 200 type-2 X-ray AGN with 0.1ltzlt1.2
• From Pacaud et a. 2006

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X-ray AGN behavior similar to lower mass radio
galaxies Also in quasar mode?
flat fraction-mass relation
IR excess torus
In field or pairs
10.0 10.5
11.5 Log(M/Mo)
10.0 10.5
11.5 Log(M/Mo)
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Next steps
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LOFAR opens up the last unexplored
wavelength region

• Unique frequency range
• ? 10 - 240 MHz
• Unprecedented sensitivity
• Time Line
• 2007 4 stations
• 2008 20 stations 20 km
• 2010 50 stations 700 km
• Science
• Reionisation, cosmic rays, transient radio
  sources
• zgt6 radio galaxies, clusters and distant
  starbursts, Specifically
• Feedback processes
• Evolution of AGN activity

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Low Band Antennas 30-80 MHz
(the not enclosed) High Band Antennas 115-240MHz
Phased arrays beams are formed electronically
and not mechanically
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Configuration

• NL lofar 20-25 core Stations 20-25 outer
  stations

E-lofar 20-30 European stations?
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60 MHz (1 ) LOFAR map with 800 sources (Oct 07)
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LOFAR detection of a z 4.2 radio galaxy!
60 MHz (1 ) LOFAR map with 800 sources (Oct 07)