High Redshift Radio Galaxies:High Redshift Radio Galaxies:The most massive galaxies up to The most massive galaxies up to

z>5?z>5?Carlos De Breuck (ESO)Carlos De Breuck (ESO)

cdebreuc@eso.orgcdebreuc@eso.org

How massive are High-z Radio Galaxies How massive are High-z Radio Galaxies (HzRGs)?(HzRGs)?

Does their AGN bother or help us?Does their AGN bother or help us? The overdense environments of HzRGs.The overdense environments of HzRGs. What is their space density?What is their space density? What is their relation with submm galaxies?What is their relation with submm galaxies?

Are HzRGs Massive?Are HzRGs Massive?Host galaxies are ellipticals.Host galaxies are ellipticals.

At z<1, powerful radio At z<1, powerful radio sources are associated with sources are associated with gE and cD galaxies.gE and cD galaxies.

At z<2.5, At z<2.5, HSTHST/NICMOS host /NICMOS host galaxy imaging show de galaxy imaging show de Vaucouleurs profiles.Vaucouleurs profiles.

Zirm et al 2003, Zirm et al 2003, Pentericci et al 2002Pentericci et al 2002

F622W F160WF622W F160WRR1/41/4

Surfa

ce B

right

ness

Su

rface

Brig

htne

ss

Are HzRGs Massive?Are HzRGs Massive?Dynamical mass Dynamical mass determinations.determinations.

3C265 (z=0.8) mass 3C265 (z=0.8) mass measured from [OII] measured from [OII] rotation curve: 8x10rotation curve: 8x101010 M MSunSun within 15kpc. within 15kpc.

CO measurements in four CO measurements in four z>3 RGs yield dynamical z>3 RGs yield dynamical masses of order 5x10masses of order 5x101111 MMSunSun within 20 kpc. within 20 kpc.

Dey & Spinrad 1996, Papadopoulos et al 2000Dey & Spinrad 1996, Papadopoulos et al 2000

offsetoffset

ΔΔ V(k

m/s

)V(

km/s

)

Are HzRGs Massive?Are HzRGs Massive?The K-z relation out to z=5.2The K-z relation out to z=5.2

HzRGs are most luminous HzRGs are most luminous galaxies in K-band.galaxies in K-band.

Follow iso-mass lines for Follow iso-mass lines for MMbarbar =10 =101212 M MSunSun..

Caveats:Caveats: Radio power dependence.Radio power dependence. Direct and/or scattered Direct and/or scattered

AGN contributions?AGN contributions? k-correction effects.k-correction effects.

De Breuck et al 2001, Rocca-Volmerange et al De Breuck et al 2001, Rocca-Volmerange et al 20042004

RedshiftRedshift

Tota

l K m

agni

tude

Tota

l K m

agni

tude

K-z diagrams of submm and K-z diagrams of submm and

X-ray selected galaxiesX-ray selected galaxies

Stern et al 2002Stern et al 2002

X-ray selected sourcesX-ray selected sources

Tota

l K m

agni

tude

Tota

l K m

agni

tude

submm selected sourcessubmm selected sources

Serjeant et al 2003Serjeant et al 2003

Radio power dependence Radio power dependence in the K-z diagram.in the K-z diagram.

3C, 6C and 7C samples show mean offsets of >0.5 in K.3C, 6C and 7C samples show mean offsets of >0.5 in K.

Eales et al 1996, Eales et al 1996, Willott et al 2003Willott et al 2003

More powerful radio More powerful radio sources contain sources contain more massive black more massive black holes holes → → more more massive host massive host galaxies?galaxies?

Provides natural Provides natural explanation why explanation why HzRG are so HzRG are so massive.massive.

Does their AGN bother us?Does their AGN bother us? Radio-loud AGN type II Radio-loud AGN type II → → natural coronograph.natural coronograph.

Contributions to observed K-band:Contributions to observed K-band: Old stellar populationOld stellar population → → what we want to know.what we want to know. Young stellar populationYoung stellar population → → estimate ages using estimate ages using

photometry across 4000Å break.photometry across 4000Å break. AGN emission linesAGN emission lines → → select line-free bands or select line-free bands or

do near-IR spectroscopy.do near-IR spectroscopy. Scattered AGN continuumScattered AGN continuum → → spectropolarimetry.spectropolarimetry. Transmitted AGN continuumTransmitted AGN continuum → → mid-IR imaging mid-IR imaging

with with SpitzerSpitzer and/or H and/or H spectroscopy. spectroscopy.

The rest-frame K-z diagram.The rest-frame K-z diagram.SpitzerSpitzer program on 70 HzRGs: program on 70 HzRGs: 1<z<5.21<z<5.2 Range of radio luminosity.Range of radio luminosity. 4 IRAC bands, IRS 16 µm (z>2), 3 MIPS bands.4 IRAC bands, IRS 16 µm (z>2), 3 MIPS bands. Sample with large amount of existing data.Sample with large amount of existing data.Goals:Goals: Imaging at peak of old stellar population Imaging at peak of old stellar population → → MassMass UV to radio SED.UV to radio SED.Stern, De Breuck, Seymour, Lacy, Zirm, Rocca-Volmerange, Stern, De Breuck, Seymour, Lacy, Zirm, Rocca-Volmerange,

Rettura, Vernet, Fosbury, Stanford, van Breugel, Miley, Rettura, Vernet, Fosbury, Stanford, van Breugel, Miley, Dickinson, Dey, McCarthy, Eisenhardt, Teplitz.Dickinson, Dey, McCarthy, Eisenhardt, Teplitz.

LyLy halos around HzRGs halos around HzRGs..

4C 41.17 (z=3.80)4C 41.17 (z=3.80)Reuland et al. 2003Reuland et al. 2003

PKS 1138-262 (z=2.16)PKS 1138-262 (z=2.16)Kurk et al. 2003Kurk et al. 2003

150 kpc150 kpc200 kpc200 kpc

Emission-line halos around Emission-line halos around HzRGs.HzRGs.

Narrow-band Ly Narrow-band Ly imaging of HzRGs often imaging of HzRGs often shows very extended halos (shows very extended halos (e.g. van Ojik et al e.g. van Ojik et al 1996, Venemans et al 2002, Reuland et al 20031996, Venemans et al 2002, Reuland et al 2003).).NameName zz Size Size

[kpc x kpc][kpc x kpc]Log Ly Log Ly [erg/s][erg/s]

PKS1138-262PKS1138-262 2.162.16 150x120150x120 44.344.3B2 0902+34B2 0902+34 3.403.40 140x100140x100 44.844.84C1243+0364C1243+036 3.573.57 160x50160x50 44.044.04C60.074C60.07 3.793.79 110x60110x60 45.145.14C41.174C41.17 3.803.80 190x130190x130 45.245.2TN J1338-TN J1338-19421942

4.104.10 150x40150x40 44.744.7

Chemically enriched emission line Chemically enriched emission line halos.halos.

Deep Keck spectroscopy shows NDeep Keck spectroscopy shows NVV1240, 1240, CCIVIV1540, He1540, HeIIII 1640 emission extending 1640 emission extending beyond the radio lobes (beyond the radio lobes (Maxfield et al 2002, Maxfield et al 2002, Villar-Martin et al 2003Villar-Martin et al 2003).).

4C+23.564C+23.56z=2.48z=2.48

80 k

pc80

kpc

Proto-clusters around Proto-clusters around HzRGs.HzRGs.

RG with 2.1<z<5.2 have an overdensity of RG with 2.1<z<5.2 have an overdensity of LyLy emitters ( emitters (e.g. Venemans et al 2002, 2004e.g. Venemans et al 2002, 2004).).

NameName zz # candidates# candidates #confirme#confirmedd

ΔΔvv

PKS1138-262PKS1138-262 2.162.16 7070 1414 ~1000~1000MRC0052-MRC0052-241241

2.862.86 7373 3737 ~900~900

MRC0943-MRC0943-242242

2.922.92 ~70~70 2929 ~800~800

MRC0316-MRC0316-257257

3.133.13 9292 3131 ~625~625

TN J2009-TN J2009-30403040

3.153.15 2020 1111 ~470~470

TN J1338-TN J1338-19421942

4.104.10 5050 3232 ~350~350

TN J0924-TN J0924-22012201

5.195.19 ~20~20 66 N/AN/A

Example:Example: TN J1338-1942 (z=4.1) contains:TN J1338-1942 (z=4.1) contains:1.1. 30 Ly30 Ly emitters ( emitters (Venemans et al 2002Venemans et al 2002))2.2. 56 g-band dropouts (56 g-band dropouts (HSTHST/ACS; /ACS; Miley et al 2004Miley et al 2004).).3.3. 6 (sub)mm galaxies (6 (sub)mm galaxies (De Breuck et al 2004De Breuck et al 2004).).

Proto-clusters around Proto-clusters around HzRGs.HzRGs.

Factor 3-5 overdensity compared to blank fields.Factor 3-5 overdensity compared to blank fields. Velocity dispersion <half of filter bandwidth.Velocity dispersion <half of filter bandwidth. If just detached from Hubble flow, M~5x10If just detached from Hubble flow, M~5x101414

MMSun.Sun. LyLy emitters have SFR=1-10 M emitters have SFR=1-10 MSunSun/yr, mm /yr, mm

sources have SFR ~ 2000 Msources have SFR ~ 2000 MSunSun/yr./yr.

Consistent with HzRGs as massive galaxies Consistent with HzRGs as massive galaxies tracing the densest regions out to z>5.tracing the densest regions out to z>5.

Space density of HzRGs.Space density of HzRGs. Space density reasonably well known out to Space density reasonably well known out to

z~3.z~3. Very uncertain beyond z=3 because only Very uncertain beyond z=3 because only

~30 z>3 radio galaxies are known to date.~30 z>3 radio galaxies are known to date.

Jarvis et al 2001, Willott et al 2001Jarvis et al 2001, Willott et al 2001RedshiftRedshift

RedshiftRedshift

1100 33 554422 66 77

22 33 44

Filtered HzRG surveys.Filtered HzRG surveys. Unfiltered radio surveys (3C, 6C, 7C, MRC, …) Unfiltered radio surveys (3C, 6C, 7C, MRC, …)

have <z>~1.have <z>~1. Most succesful high-z selection is based on Most succesful high-z selection is based on

Ultra Steep Radio spectra (USS), <z>~2.5.Ultra Steep Radio spectra (USS), <z>~2.5.

De Breuck etal 2000-2004De Breuck etal 2000-2004RedshiftRedshift1100 33 554422 66

Radi

o Sp

ectra

l Ind

exRa

dio

Spec

tral I

ndex

Uses concave shape of Uses concave shape of radio spectrum.radio spectrum.

k-correction shifts k-correction shifts steeper part to steeper part to observed observed wavelengths.wavelengths.

>90% of z>3 galaxies >90% of z>3 galaxies discovered via USS.discovered via USS.

TN J0924-2201 at z=5.2TN J0924-2201 at z=5.2 Extreme USS source with K=21.3 host galaxy.Extreme USS source with K=21.3 host galaxy. Surrounded by 6 confirmed Ly emitters.Surrounded by 6 confirmed Ly emitters.

van Breugel etal 1999van Breugel etal 1999WavelengthWavelength

Flux

FFl

ux F

λλ

Venemans et al 2004Venemans et al 2004

K-band + radioK-band + radio

USS sources without redshifts.USS sources without redshifts. ~30% of USS sources ~30% of USS sources

fail to yield a redshift fail to yield a redshift after 1h+ of Keck/VLT after 1h+ of Keck/VLT spectroscopy.spectroscopy.

Either no emission at Either no emission at all or featureless all or featureless continuum.continuum.

Very obscured Very obscured galaxies or at z>7?galaxies or at z>7?

Compact (Compact (→ → young?) young?) radio morphologies.radio morphologies.

WavelengthWavelength

Flux

FFl

ux F

νν

De Breuck et al 2001De Breuck et al 2001

Example: WN J0305+3525.Example: WN J0305+3525. Bright (sub)mm source.Bright (sub)mm source. Not detected in 12.6 ks with Chandra Not detected in 12.6 ks with Chandra →→ heavily heavily

obscured source with nobscured source with nHH~few 10~few 102323 cm cm-2-2.. Radio-optical SED consistent with z~3.Radio-optical SED consistent with z~3.

Reuland et al 2003Reuland et al 2003Log observed frequencyLog observed frequency

νν F F

νν

K-band + radio + K-band + radio + SCUBA 850µmSCUBA 850µm

Sub-mm observations of Sub-mm observations of HzRGs.HzRGs.

S850 rises with zS850 rises with z

Archibald et al 2001, Reuland et al 2004Archibald et al 2001, Reuland et al 2004RedshiftRedshift

SS 85085

0

RedshiftRedshift

Num

ber

Num

ber

Detection fraction z<2.5 ~15 %Detection fraction z<2.5 ~15 %Detection fraction z>2.5 ~50 %Detection fraction z>2.5 ~50 %

Sub-mm emission: AGN or Sub-mm emission: AGN or starburst?starburst?

UV polarizationUV polarization

SS 85085

0

Dom

inat

ed b

y Do

min

ated

by

scat

tere

d qu

asar

scat

tere

d qu

asar

HzRGs contain strong AGN HzRGs contain strong AGN that could heat the dust.that could heat the dust.

No correlation between No correlation between radio power and Sradio power and S850850..

Anti-correlation between Anti-correlation between SS850 850 and UV polarization.and UV polarization.

All submm-loud HzRGs All submm-loud HzRGs also show CO emission also show CO emission tracing the gas reservoir tracing the gas reservoir feeding starbursts.feeding starbursts.

→ → HzRGs may be radio-loud HzRGs may be radio-loud counterparts of SMGs?counterparts of SMGs?

D

omin

ated

by

Do

min

ated

by

yo

ung

youn

g st

ars

star

s

Star Formation History of Star Formation History of HzRGs.HzRGs.

22

<L<L 8

50850>>

LLFIRFIR ~ 10 ~ 101313 L LSunSun.. SFR ~ 1500 MSFR ~ 1500 MSunSun/yr./yr. SFR increases with SFR increases with

redhsift at least until z~4. redhsift at least until z~4.

→ → More luminous than More luminous than ULIRGs.ULIRGs.

→ → Forming the bulk of their Forming the bulk of their stellar populations.stellar populations.

What is the role of mergers?What is the role of mergers?RedshiftRedshift44 6600

CO emission in CO emission in HzRGsHzRGs

CO traces HCO traces H22 →→ M(H M(H22) ~ 1 to 5x10) ~ 1 to 5x101010 M MSun.Sun. CO velocity widths up to 1000 km/s CO velocity widths up to 1000 km/s →→ M Mdyndyn » 10 » 101111 M MSunSun CO redshift often offset from AGN redshift CO redshift often offset from AGN redshift → → real real

systemic redshift of AGN host galaxy.systemic redshift of AGN host galaxy. In at least 2/5 cases CO is distributed in 2 In at least 2/5 cases CO is distributed in 2

components.components.NameName zz ΔΔVVCOCO

[km/s][km/s]SSCO CO ΔΔVV

[Jy [Jy km/s]km/s]

B3 B3 J2330+3927J2330+3927

3.03.099 500500 1.3± 1.3±

0.30.3TN TN J0121+1320J0121+1320

3.53.522

700700 1.2± 1.2± 0.40.4

6C 1909+726C 1909+72 3.53.544

530530 1.6± 1.6± 0.30.3

4C60.074C60.07 3.73.799

>100>10000

2.5± 2.5± 0.40.4

4C41.174C41.17 3.83.800

900900 2.1± 2.1± 0.20.2

CO emission in CO emission in 4C41.174C41.17

De Breuck et al, in prep.De Breuck et al, in prep.

CO is in 2 components with M(HCO is in 2 components with M(H22)≈3x10)≈3x101010 M MSunSun.. Each component coincident with a dark lane in LyEach component coincident with a dark lane in Ly

Mergers seen in CO?Mergers seen in CO?

De Breuck et al, in prep.De Breuck et al, in prep.

VelocityVelocity

Offse

tOff

set

In 4C60.07 and In 4C60.07 and 4C41.17, the CO(4-3) is 4C41.17, the CO(4-3) is in two components, in two components, separated by ~500 separated by ~500 km/s and ~15 kpc.km/s and ~15 kpc.

Suggest merger of two Suggest merger of two gas-rich galaxies cfr. gas-rich galaxies cfr. local ULIRGs.local ULIRGs.

But no galaxies seen in But no galaxies seen in optical/near-IR imaging optical/near-IR imaging → → high obscuration?high obscuration?

ConclusionsConclusions The Hubble K-z diagram shows that HzRGs are The Hubble K-z diagram shows that HzRGs are

amongst the most massive galaxies known to amongst the most massive galaxies known to z>5.z>5.

At z<2.5, their host galaxies are ellipticals.At z<2.5, their host galaxies are ellipticals. Many (most?) HzRGs are in giant LyMany (most?) HzRGs are in giant Ly haloes and haloes and

proto-clusters.proto-clusters. Space density is ill constrained at z>3, where Space density is ill constrained at z>3, where

they are only found in USS samples.they are only found in USS samples. At z>3, RGs are strong submm sources powered At z>3, RGs are strong submm sources powered

by starbursts. Their enormous Lby starbursts. Their enormous LFIRFIR suggests they suggests they are forming the bulk of their stellar population.are forming the bulk of their stellar population.

CO emission in z>3 RGs is often in 2 CO emission in z>3 RGs is often in 2 components, suggesting gas-rich mergers.components, suggesting gas-rich mergers.

Future WorkFuture Work Rest-frame K-z diagram using Rest-frame K-z diagram using Spitzer Spitzer → → mass. mass. Larger samples of z>3 RG to constrain their Larger samples of z>3 RG to constrain their

space density (e.g. Texas Oxford One space density (e.g. Texas Oxford One Thousand).Thousand).

Very wide-field (1000+ sq. degrees) near-IR Very wide-field (1000+ sq. degrees) near-IR surveys to determine HzRG space density.surveys to determine HzRG space density.

Expand coverage around existing HzRG proto-Expand coverage around existing HzRG proto-clusters to determine their full size (»2 Mpc).clusters to determine their full size (»2 Mpc).

Deep CO observations with wide frequency Deep CO observations with wide frequency coverage to study where most of the mass is coverage to study where most of the mass is located located → → possible with eVLA and ALMA.possible with eVLA and ALMA.

Coming in 2007!Coming in 2007!