EVLA WILL EXPLORE NEW PARAMETER SPACE

• Proc. Greenbank Workshop on Serendipitous Discovery in Radio Astronomy 1983

– Martin Harwit

• “If there were less requirement for theoretical justification for building an instrument, you would have a better chance of making a discovery”

EVLA DISTANT RADIO GALAXY STUDIES• SUBJECT OF THIS TALK - HzRGS

– POWERFUL HIGH-z RADIO GALAXIES + ENVIRONMENTS• (z > 2, L500MHz ~ 1027 W/ Hz)

• SPECTACULAR NATURE – Progenitors of cDs

• Formation and evolution of most massive galaxies

– Pinpoint z > 2 protoclusters• Formation and evolution of rich clusters

– Cast• PhD Theses: Laura Pentericci, Carlos De Breuck, Jaron Kurk, Bram Venemans, Roderik Overzier• Collaborators: Wil van Breugel, Chis Carilli, Holland Ford, Nina Hatch, GM, Huub Rottgering++

• EVLA + HzRGS: PROBES OF MASSIVE GALAXY + PROTOCLUSTERS– Molecular gas

– Nonthermal continuum starburst emission

RADIO EMISSION FROM HzRGS

SPECTROSCOPY OF ULTRA STEEP-SPECTRUM RADIO SOURCES IS MOST EFFICIENT TECHNIQUE

FOR FINDING THE MOST DISTANT RADIO GALAXIES

Most distant radio sources have steeper radio spectrae.g. Blumenthal & Miley 1988

~ 200 HzRGs with z > 2. Record holder TN J0924-2201: z = 5.2

PUSH TO HIGHER z WITH LOFAR Hopefully z ~ 6 – 8 – into the EoR

De Breuck et al 2000

WHAT ARE HOST GALAXIES OF HzRGS?

• CLUES TO THEIR NATURE

– Luminous in IR > Massive– Clumpy (HST) > Structure assembling

K – z Hubble Diagram

HST PC: 4C41.17 z = 3.8

Simulations of forming massive

galaxy (Carlsberg 1994)

Radio Galaxies form bright envelope

(De Breuck et al. 2002)

100kpc

HST PC: 1138-29 z=2.2

WHAT ARE HOST GALAXIES OF HzRGS?

• CLUES TO THEIR NATURE

– Luminous in IR > Massive– Clumpy (HST) > Structure assembling– Spectroscopy > star-forming (few x 102 MSun/yr)

Spectrum resembles starburst galaxyDey et al. 1997

FORMING MASSIVE GALAXIES

WHAT ARE HOST GALAXIES OF HzRGS?

• MORE CLUES TO THEIR NATURE

– Giant Ly α Halos• ~100kpc, cD-sized

– CDM SIMULATIONS: At Largest Overdensities >

• Most massive galaxies formAND • Richest clusters form

FORMING DOMINANT CLUSTER GALAXIES?

1138-26 at z =2.2, Kurk et al. 2003

FORMING MASSIVE GALAXIES

SPECTRAL ENERGY DISTRIBUTIONS EXAMPLE: 4C23.56 z = 2.5

De Breuck et al 2008

Radio

Ultra-steepspectrum

X-Ray AGN

Relativistic Plasma

Gas

Dust

BUILDING BLOCKS OF DISTANT RADIO GALAXIES

Stars

Active Nucleus

fromMiley & De BreuckAstronomy &Astrophysics Reviews2008, Vol. 15, pp67-144

Constituents interact

Feedback

Combination greater than

sum of individual

diagnostics

DEEPEST HST/ACS IMAGE OF HzRG

Miley et al. 2006, Astrophys. J. 650, 29LHatch et al 2007, 2008

Important contributionsRoderik OverzierNina Hatch

MASSIVE GALAXY EVOLUTION -CASE STUDY1138-262, z = 2.2 ~10.6 x 109 light years away

Small satellite galaxies are “flies” in the “spiderweb”

IR Luminosity ~ 1012 MSun: One of most massive galaxies in Universe

SPIDERWEB GALAXY

Radio SynchrotronRelativistic plasma

VLA

LyαIonized gas VLT

SPIDERWEB GALAXY ILLUSTRATES HzRG PROPERTIESCLUMPY + EMBEDDED IN HUGE IONIZED GAS HALO

~ 200 kpc 6 x 105 light yr

~50% of light is diffuse SFR

~ 80 MSun /yr

(Hatch et al. 2007)

HIGH-REDSHIFT RADIO GALAXY HOSTS

• Laboratories for studying– Merging– AGN feedback– Downsizing– Interaction with surrounding

protocluster

• Search for additional SW galaxies – HST WFC3 + ACS

• Cycle 17

• Tracing history of merging in SW underway– 3D-Spectroscopy

• IR ESO/VLT• Optical GEMINI

– Compare with simulations• Note the presence of linear flies

Schaye et al. 2007

CONSTRAINING HISTORY OF THE SPIDERWEB

Selecting protocluster galaxies Modeling stellar populations

Hatch et al. 2008, submitted

Most mass is centrally concentrated but most star formation occurring in low-mass surrounding satellite galaxies

HzRGS EFFICIENT FINDER OF PROTOCLUSTERSGALAXY OVERDENSITIES + DOMINANT MASSIVE GALAXY

Squares: recedingCircles: approaching

Radio Galaxy

Radio Galaxy

Similar data available for 7 z > 2 HzRG targets

Also HzRGs with overdensities in Hα emitters, Lyman and Balmer break objects

Lyα IMAGING + SPECTROSCOPY: EXAMPLE 1338-19 at z ~ 4.1. Two 7’ x 7’ VLT/FORS FIELDS see Miley & De Breuck review 2008, Venemans et al. 2007

v ~ 325 km/s

37 Ly Emitters

ENVIRONMENT OF DISTANT RADIO SOURCES• CONTAIN MOST MASSIVE FORMING GALAXIES

• GALAXY OVERDENSITIES (3 – 15)

• MASSES ~ ANCESTOR OF RICH CLUSTERS

– Size ~ 3 – 5 Mpc

– Moverdensity ~ <ρ>V(1+δM) ~ 1015 MSun ~ nearby galaxy clusters

• STATISTICS CONSISTENT WITH ALL LOCAL CLUSTERS HAVING PREVIOUSLY HOUSED A LUMINOUS RADIO SOURCE

– Lifetime of radio source few x 107 y– Age of Universe 13 x 109 y

• >100 times more “dead” radio galaxies as active ones

ALL INGREDIENTS OF PROTOCLUSTERS

HzRGS PINPOINT ANCESTORS OF RICH GALAXY CLUSTERS IN THE EARLY UNIVERSE

PROTOCLUSTER HISTORY – CASE STUDY 1138-26 (The “Spiderweb Protocluster”) z = 2.2

(Kurk PhD Thesis)

BLUE SYMBOLSLy excess

– YOUNG STARS?

RED AND BLACK SYMBOLS4000A break and Hexcess galaxies

– OLD STARS?

Red and black objects are more concentrated than Lya

Consistent with more massive and older settling towards center

POPULATION STUDY

SOME RESULTS ON HzRG PROTOCLUSTERS

• 6/6 radio galaxies observed sufficiently deeply have >20 associated Ly α (or Hα) galaxies– >140 spectroscopically confirmed “protocluster” galaxies

• ~ 15% spatially resolved Lyα (kinematics)

• Overdensity of Ly a emitters ~ 5 – 15– c.f. Lyα field surveys (eg. LALA)

• Structure Sizes ~ 3 – 5 Mpc– Larger than 8’x8’ FORS field, but bounded in some directions

• Well matched to EVLA 1.4 - 5 GHz

• Velocity dispersions 300 – 1000 km/s– Velocity dispersions x 3 smaller than NB filter width

• Easily observed by WIDAR

• SFR of Ly a emitters ~ 0.5 – 30 MSun/yr– Lyα and UV continuum fluxes

• Detectable with EVLA at 1.4 – 5 GHz

Relativistic Plasma

Gas

Dust

WHAT CONSTITUENTS OF HzRGS WITH EVLA?

Stars

Active Nucleus

Constituents interact

Feedback

SN Remnants of star formation

Womb of star formation

MOLECULAR GAS FROM HzRGS

EXAMPLE 4C41.17 z = 3.8CO (4 – 3) (IRAM)De Breuck et al 2005

1000 km/s

10”

~ 7 HzRGS with reported CO detections Inferred masses ~ 1010 – 1011 Msun

BUT!! Many assumptions CO/H2, T, n etc Needed several transitions and species + spatial distributions

to produce robust conclusion

Diagnostic of cold gas reservoir for SFRBut how did first SFR occur?

MOLECULAR GAS FROM HzRGSDiagnostic of cold gas reservoir for SFR

• Limitations of existing facilities

– Sensitivities marginal

– Velocity coverage (~ 1000 km/s) comparable with

• Kinematics of HzRGs (~ 1000 km/s)

• Kinematics of surrounding protoclusters)

Spurious results easy e.g. due to standing waves

Van Ojik et al ’94Luckily repeated before pub

Did not repeat

CO FROM HzRGS – WHY EVLA • Wavelength coverage of WYFAR

• Huge improvement in sensitivity

• Multiple transitions– Temperature and density profiles - modeling

• EVLA + ALMA

• More spatially resolved information– Relation to stars and other gaseous components

• Possible unconventional star formation mechanisms at high z– Relation to radio

• Jet-induced star formation?– e.g. Rees 1988

• Large statistical samples possible– CO and spatial distribution as function of other properties

4C41.17 HST Bicknell et al. 2000

RELEVANT MOLECULAR LINESPowerful combination of EVLA + ALMA

• EVLA can study important lower-order CO transitions both for HzRGS and z >2 protoclusters

– Survey of HzRGs will cover protocluster centers at no cost

• Many protocluster galaxies

– WIDAR easily will cover both to Δ(velocities) of HzRGs and protoclusters

• EVLA may also detect low-order HCN and HCO+ transitions to probe denser molecular gas (e.g. Papadopoulos 2007)

REDSHIFT RANGE

CO (1→0)115.3 MHz

CO (2→1)230.5 MHz

CO (3→2)345.8 MHz

CO (4→3)461.0 MHz

CO (5→4)576.2 MHz

2.0 - 4.7 EVLA (18 – 38 MHz)

ALMA

2<z<3.0 B3

3<z<3.6 B2?

ALMA

2<z<4.3 B3,4

4.3<z<5.1B2?

ALMA

2<z<4.7

3.6 – 5.2 EVLA (50 – 37 MHz)

EVLA AND z > 2 PROTOCLUSTERS - 1

• Why study 2 < z < 5 protoclusters?

– Crucial epoch in evolution of galaxies and clusters

• Peak of AGN space density

• Peak of global SFR

– Higher fraction of massive stars (SNe) than at z ~ 0??

• Formation of “Red sequence”

– Galaxies becoming red and dead

– Hundreds of galaxies at same z

• Statistical samples and population studies

– Differences between protocluster and field

– Compare with rich clusters at z ~ 1 and z ~ 0

EVLA AND z > 2 PROTOCLUSTERS - 2

• Radio diagnostics of star formation in forming clusters – SF at high z may be different than at low z

• IMF and evolution, Presence of AGN, shocks etc• IMF with more massive stars?

– Synchrotron emission complementary to other SF diagnostics• Remnant of SNe

– Samples different region of IMF

– SF in Protoclustersclusters may be different to that in field• SNe rate of early-type galaxies x 3 larger in clusters than field

(low-z) Mannucci et al. 2007)

EVLA AND z > 2 PROTOCLUSTERS - 3• Power of EVLA

– Can detect galaxies with SFR of few MSun/ year at z ~ 3

(12 hrs ~ 1 μJY at 5 GHz )• Comparable with measured SFR from observed Lyα emitters

– Can search for SFR trends with location in protocluster• Diagnostic of evolution

– Spatial comparison with dust/ millimeter (ALMA)

and optical/IR diagnostics• IR –radio correlation at high z

– e.g. talk by Eric Murphy

EVLA AND SF RADIO EMISSION IN HzRGS

• Similar studies of star formation in the most massive galaxies at z > 2– Can detect SF from flies in Spider-web type galaxies?– Spatial comparison can constrain formation history

• BUT– Presence of HzRG means stringent dynamic range requirements

• Ultra-steep spectrum helps– 5GHz preferred to 1.4 GHz because of ultra-steep spectrum of HzRG

• Spatial extension of HzRGs helps– ~1 in few x 105 desirable

CONCLUSION

PROBING EVOLUTION OF MASSIVE GALAXIES & CLUSTERS IN EARLY UNIVERSE WITH HzRGS

• Combination of diagnostics needed

– Whole > Sum of parts

• EVLA will provide crucial info on

– star formation processes

• HzRGs prime targets for EVLA

SUMMARY• Power of EVLA for studying z > 2 starbursts

– Can detect nonthermal emission remnants from star formation

• few x MSun SFR, i.e. Ly α emitting galaxies

– Sensitivity bandwidth and spatial resolution to study lower CO transitions• Synergy with ALMA + large optical/IR telescopes ++++

• EVLA + HzRG Hosts – Progenitor cD galaxies

– Laboratories for studying formation of most massive galaxies• Merging process spatially resolvable

– History of formation

– Many bright building blocks, each with own separate diagnostics• Whole is greater than some of parts – interaction

• EVLA + HzRG Environments – Protoclusters

– Hundreds of galaxies at same distance• Spatial distribution and population studies feasible

– Presence of cD progenitor candidate link with z < 1 rich clusters• EVLA study of large sample of protoclusters feasible

• Dynamic range > 105 desirable

POSSIBLE FOOD FOR EVLA• PILOT PROJECT (SHARED RISK – 2010?)

– 3 HzRGS (z ~ 2.3, z ~ 3.1, z ~ 4.1)• NT Continuum from starbursts HzRG + protocluster

– 5 GHz Config A 1 x 12h– 5 GHz Config B 1 x 12h– 1.4 GHz Config A 1 x 12h

• CO (1,0), CO (2,1) from HZRG + protocluster center– 20 – 50 GHz Config C? 2 x 12h

– Total 15 x 12h

• POSSIBLE FOLLOWUP KEY PROJECT (2011 – 2013?)– 50 HzRGs

• 250 x 12h– Unique constraints on evolution of clusters and massive galaxies

» ALMA for higher order CO transitions» Complementary optical/IR data