p. 1p. 1

Two distinct Accretion processes in radio galaxies

Huub RöttgeringLeiden Observatory

• 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• z>2 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

p. 3p. 3

p. 4p. 4

VLT interferometer observations with MIDIof NGC 1068

Correlated Flux density spectrum

UV plane

p. 5p. 5

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, Tristamin prep.

9 other AGN show ‘similarStructure, except the radioGalaxy CenA that does not seem to have a torus

8 micron imageBox: 60*60 milli-arcs

• 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• z>2 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

For massive galaxies, the rate of activity and energy output

sufficient to heat their hot halos (Best et al. 2005)

p. 8p. 8

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 Tasse’s thesis– Best, Cohen, Le Borgne, Pierre, HR, et al.

p. 9p. 9

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

p. 10

Evolution of the mass-fraction

p. 10

A break appears at log(M/Mo) = 10.5-10.8

Upturn of the radio LF due to less massive galaxies become more active Z=0: Log(P1.4)>24

Z=0: Log(P1.4)>25

Fract

ion

of

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s th

at

are

rad

io lou

d

9.5 10.5 11.5Log(M/Mo)

p. 11p. 11

450

Overdensity as

a function of scale

450 kpc

250 kpc 75 kpc

p. 12p. 12

• 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?

Dif

fere

nce

in D

ensi

tyR

adio

sou

rce

host

and

no

rmal

gal

axy

10.0 10.5 11.0Log(M/Mo)

p. 13p. 13

p. 14p. 14

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

10.5 10.5 11 Log(M/Mo)

Delt

a IR

p. 15

Summary

• Radio galaxies with Log(M/Mo) > 10.5– Steep fraction-mass relation– Located in overdensities of scale 450 kpc– Do not have IR excessIdentify with accretion of hot gas

• Radio galaxies with Log(M/Mo) < 10.5– Flatter fraction-mass relation– located in overdensities of scales of 75 kpc– Have an IR excessIdentify with merging event driving cold gas to the

center

p. 15

p. 16

What about X-ray AGN?

Similar analysis for 200 type-2 X-ray AGN with

0.1<z<1.2 From Pacaud et a. 2006

p. 16

p. 17

X-ray AGN behavior similarto lower mass radio galaxiesAlso 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)

p. 18

Next steps

p. 18

• Unique frequency range ~ 10 - 240 MHz

• Unprecedented sensitivity• Time Line

2007: 4 stations2008: 20 stations ~ 20 km 2010: 50 stations ~ 700 km

• Science– Reionisation, cosmic rays, transient radio sources– z>6 radio galaxies, clusters and distant starbursts, Specifically– Feedback processes– Evolution of AGN activity

LOFAR opens up the last ``unexplored’’

wavelength region

p. 20p. 20

Low Band Antennas: 30-80 MHz (the not enclosed) High Band Antennas:

115-240MHz

Phased arrays: beams are formed electronically and not

mechanically

p. 21p. 21

ConfigurationNL lofar: 20-25 core Stations & 20-

25 outer stations

E-lofar: 20-30 European stations?

60 MHz (1 %) LOFAR

mapwith 800 sources

(Oct 07)

LOFAR detection of a z = 4.2 radio galaxy!

60 MHz (1 %) LOFAR

mapwith 800 sources

(Oct 07)