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EVLA WILL EXPLORE NEW PARAMETER SPACE

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”.

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EVLA WILL EXPLORE NEW PARAMETER SPACE

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  1. 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”

  2. 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

  3. RADIO EMISSION FROM HzRGS Most distant radio sources have steeper radio spectra e.g. Blumenthal & Miley 1988 De Breuck et al 2000 SPECTROSCOPY OF ULTRA STEEP-SPECTRUM RADIO SOURCES IS MOST EFFICIENT TECHNIQUE FOR FINDING THE MOST DISTANT RADIO GALAXIES ~ 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

  4. WHAT ARE HOST GALAXIES OF HzRGS? HST PC: 4C41.17 z = 3.8 • CLUES TO THEIR NATURE • Luminous in IR> Massive • Clumpy (HST) > Structure assembling K – z Hubble Diagram 100kpc Simulations of forming massive galaxy (Carlsberg 1994) Radio Galaxies form bright envelope (De Breuck et al. 2002) HST PC: 1138-29 z=2.2

  5. 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 galaxy Dey et al. 1997 FORMING MASSIVE GALAXIES

  6. 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 form AND • Richest clusters form FORMING MASSIVE GALAXIES 1138-26 at z =2.2, Kurk et al. 2003 FORMING DOMINANT CLUSTER GALAXIES?

  7. SPECTRAL ENERGY DISTRIBUTIONS EXAMPLE: 4C23.56 z = 2.5De Breuck et al 2008 X-Ray AGN Radio Ultra-steep spectrum

  8. BUILDING BLOCKS OF DISTANT RADIO GALAXIES from Miley & De Breuck Astronomy & Astrophysics Reviews 2008, Vol. 15, pp67-144 Relativistic Plasma Constituents interact Gas Feedback Dust Combination greater than sum of individual diagnostics Stars Active Nucleus

  9. MASSIVE GALAXY EVOLUTION -CASE STUDY 1138-262, z = 2.2 ~10.6 x 109 light years away IR Luminosity ~ 1012 MSun: One of most massive galaxies in Universe DEEPEST HST/ACS IMAGE OF HzRG SPIDERWEB GALAXY Miley et al. 2006, Astrophys. J. 650, 29L Hatch et al 2007, 2008 Important contributions Roderik Overzier Nina Hatch Small satellite galaxies are “flies” in the “spiderweb”

  10. SPIDERWEB GALAXY ILLUSTRATES HzRG PROPERTIESCLUMPY + EMBEDDED IN HUGE IONIZED GAS HALO Lyα Ionized gas VLT Radio Synchrotron Relativistic plasma VLA ~50% of light is diffuse SFR ~ 80 MSun /yr (Hatch et al. 2007) ~ 200 kpc 6 x 105 light yr

  11. 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

  12. 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

  13. HzRGS EFFICIENT FINDER OF PROTOCLUSTERSGALAXY OVERDENSITIES + DOMINANT MASSIVE GALAXY 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 Radio Galaxy Radio Galaxy 37 Ly Emitters v ~ 325 km/s Squares: receding Circles: approaching Similar data available for 7 z > 2 HzRG targets Also HzRGs with overdensities in Hα emitters, Lyman and Balmer break objects

  14. 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

  15. PROTOCLUSTER HISTORY – CASE STUDY 1138-26 (The “Spiderweb Protocluster”) z = 2.2(Kurk PhD Thesis) POPULATION STUDY BLUE SYMBOLS Lya excess – YOUNG STARS? RED AND BLACK SYMBOLS 4000A break and Ha excess galaxies – OLD STARS? Red andblack objects are more concentrated than Lya Consistent with more massive and older settling towards center

  16. 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

  17. WHAT CONSTITUENTS OF HzRGS WITH EVLA? SN Remnants of star formation Relativistic Plasma Gas Constituents interact Womb of star formation Feedback Dust Stars Active Nucleus

  18. MOLECULAR GAS FROM HzRGS • Diagnostic of cold gas reservoir for SFR • But how did first SFR occur? EXAMPLE 4C41.17 z = 3.8 CO (4 – 3) (IRAM) De Breuck et al 2005 10” ~ 7 HzRGS with reported CO detections Inferred masses ~ 1010 – 1011 Msun 1000 km/s BUT!! Many assumptions CO/H2, T, n etc Needed several transitions and species + spatial distributions to produce robust conclusion

  19. 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) Did not repeat Spurious results easy e.g. due to standing waves Van Ojik et al ’94 Luckily repeated before pub

  20. 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

  21. 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)

  22. 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

  23. 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)

  24. 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

  25. 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

  26. CONCLUSIONPROBING 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

  27. 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

  28. 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

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