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CO(1-0) survey of High-z Radio Galaxies: ATCA/CABB as crucial complement to ALMA

CO(1-0) survey of High-z Radio Galaxies: ATCA/CABB as crucial complement to ALMA. Bjorn Emonts (CSIRO Astronomy & Space Science/ATNF)

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CO(1-0) survey of High-z Radio Galaxies: ATCA/CABB as crucial complement to ALMA

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  1. CO(1-0) survey of High-z Radio Galaxies:ATCA/CABB as crucial complement to ALMA Bjorn Emonts (CSIRO Astronomy & Space Science/ATNF) Ilana Feain (CASS), Minnie Mao (U. Tasmania), Ray Norris (CASS), George Miley (Leiden Obs.), Montse Villar-Martin (IAA Granada), Huub Rotggering (Leiden Obs.), Elaine Sadler (U. Sydney), Ron Ekers (CASS) D.J. Saikia, T. Oosterloo, R. Morganti, G. Rees, E. Mahony, C. Carilli, G. van Moorsel, J. Stevens, M. WIerenga, A. Berciano, K. Coppin, K. Randall, C. Tadhunter

  2. High-z Radio Galaxies (HzRG) • Most massive galaxies in Early Universe • Central proto-cluster galaxies (e.g. Venemans et al. 2007) anchestors of local rich cluster ellipticals • Clumpy optical morphology (merging systems) (Pentericci et al. 2001); • Radio jets vigorously interact with ISM (Humphrey et al. 2006) + alignments jets with UV/optical and CO (Chambers et al 1987; McCarthy et al. 1978; Klamer et al. 2004). • Among best studied high-z objects • Strong radio continuum beacon for tracing faint host galaxy/proto-cluster; • Optical quasar-core generally shielded by torus To fully understand HzRGs: 4C41.17 (z = 3.8) Radio cont. • Holistic approach! (Reuland et al. 2003) Lyα (warm ionised gas)

  3. Molecular gas in HzRG • Molecular gas: raw ingredient for star formation • H2 virtually invisible -- 12CO strong tracer (rotational transitions): CO(1-0) [115 GHz], CO(2-1) [230 GHz], CO(3-2) [345 GHz], CO(4-3) [460 GHz], etc. • 1991: First observations of CO at z > 2 (Brown & Vanden Bout 1991) • CO as tracer for molecular gas in HzRGs: • First (single-dish) surveys failed to detect CO (Evans et al 1996, van Ojik et al 1997) • Since then, CO detected in individual HzRG (Miley & De Breuck 2008; also Scoville et al. 1997, Papadopoulos et al. 2000, 2001, Alloin et al. 2000, De Breuck et al. 2003a,b, 2005, Greve et al. 2004, Klamer et al. 2005, Ivison et al. 200,; Nesvadba et al. 2009) • CO can be resolved on scales of tens of kpc (e.g. Papadopoulos et al. 2000) 4C41.17 (z = 3.8) De Breuck et al. (2005) Reuland et al. (2003); Carilli et al (1997)

  4. CO studies of HzRG • Major limitations of starting comprehensive studies of high-z CO: • Limited bandwidth of existing mm observatories at high obs. freq. (often not wider than CO signal or accuracy of redshift) • High observing frequencies (>100 GHz) of mm observatories: Only target higher-order CO(J,J-1) transition at high-z. - High-order transitions trace dense and thermally excited gas in starburst/AGN region; - Low-order transitions trace less dense, widespread and sub-thermally excited molecular gas; large reservoirs of molecular gas missed by observations of high- order transitions (e.g.Papadopoulos et al. 2000,2001, Greve et al. 2003, Riechers et al. 2010, Daddi et al. 2010, Carilli et al. 2010, Ivison et al. 2010, 2011) Ground-transition CO(1-0): most robust tracer for molecular gas at high-z (incl low-density, wide-spread and sub-thermally excited component) -- crucial for tracing the overall molecular gas content!

  5. ATCA/CABB: upgraded in 2009 • ATCA Compact Array Broadband Backend (CABB) has overcome these limitations: • 4 (2x2) GHz bandwidth, 1 MHz res. • Observing frequencies < 50 GHz 3mm (84-105 GHz); 7mm (30-50 GHz); 15mm (16-25 GHz) • Hybrid array configurations with baselines as short as 31m. e.g. at fobf = 40 GHz (7mm band) Δv ~15,000 km/s per 2 GHz! Australia Telescope Compact Array (Narrabri, NSW) H75 hybrid array • Similar to EVLA/WIDAR • in the northern hemisphere • down to dec -25o • (elevation +30o for mm work)

  6. ATCA/CABB: upgraded in 2009 • ATCA’s Compact Array Broadband Backend (CABB) has overcome these limitations: • 4 (2x2) GHz instantaneous bandwidth • Observing frequencies < 50 GHz 3mm (84-105 GHz); 7mm (30-50 GHz); 15mm (16-25 GHz) • Hybrid array configurations SMG (z=4.8) LESS J033229.4 Coppin et al. (2011): First detection of high-z CO with ATCA/CABB: CO(2-1) in submm-galaxy at z=4.8 !! MH2 = 1.6 x 1010 Msun (α[MH2/LCO]= 0.8)

  7. CO(1-0) survey of HzRG with ATCA/CABB • First systematic survey of CO(1-0) in unbiased sample of HzRGs. • Sample selection: All HzRGs from MRC catalogue (unbiased in IR, submm, etc): - observable in ATCA 7mm band (1.5 < z < 3) - dec < -20 - HST imaging & Spitzer data available 14 sources • Status: • - 6 sources observed • (tint ~15h per source) • - 5 sources scheduled in • Aug/Sept CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  8. CO(1-0) survey of HzRG with ATCA/CABB • Pilot study: Performance of ATCA/CABB • MRC 2104-242 (z = 2.5); fobs = 33 GHz (optimum CABB freq.) • Upper limit MH2 < 2 x 1010 Msun(α[MH2/LCO]= 0.8) pre-CABB tint = 19.5h CABB! radio cont. 0.1, 0.3, 1.0, 1.7, 2.4mJy/bm σline = 0.45 mJy/bm/ch1MHz σcont = 0.29 μJy/bm • Emonts et al. 2011, MNRAS, in press. (arXiv/1103.5806)

  9. CO(1-0) survey of HzRG with ATCA/CABB • Pilot study: Performance of ATCA/CABB • MRC 0943-242 (z = 2.9) – very edge of 7mm band • Tentative off-nuclear detection (MH2 = 6 x 1010 Msun; α[MH2/LCO]= 0.8) radio cont. 0.4, 1.0, 2.0, 3.0 mJy/bm tint = 19h • Emonts et al. 2011, MNRAS, in press. (arXiv/1103.5806) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  10. CO(1-0) survey of HzRG with ATCA/CABB • CO(1-0) in z=1.92 radio galaxy MRC 0152-209 Pentericci et al. (2000, 2001) ATCA/CABB zopt MH2 = 6 x 1010 Ms (α[MH2/LCO]= 0.8) Δv = 400 km/s • Most significant (S/N) CO(1-0) • detection in HzRG to date! • Only two other known CO(1-0) • detections in HzRG Emonts et al. (2011), ApJL accepted (arXiv/1105.0739) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  11. CO(1-0) survey of HzRG with ATCA/CABB • CO(1-0) in z=1.92 radio galaxy MRC 0152-209 Pentericci et al. (2000, 2001) ATCA/CABB TN J0924–2201 (z =5.2) ATCA pre-CABB MH2 = 6 x 1010 Ms (α[MH2/LCO]= 0.8) Δv = 400 km/s • Most significant (S/N) CO(1-0) • detection in HzRG to date! • Only two other known CO(1-0) • detections in HzRG MH2~ 1011 Ms Feain et al. (2005) Emonts et al. (2011), ApJL accepted (arXiv/…..) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  12. CO(1-0) survey of HzRG with ATCA/CABB • CO(1-0) in z=1.92 radio galaxy MRC 0152-209 Pentericci et al. (2000, 2001) ATCA/CABB MH2 = 6 x 1010 Ms (α[MH2/LCO]= 0.8) Δv = 400 km/s 83 kpc 8 kpc Emonts et al. (2011), ApJL accepted (arXiv/1105.0739) • MRC 0152-209 contains large amounts of • molecular gas that has not yet been depleted • by star formation or radio-AGN feedback. CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  13. CO(1-0) survey of HzRG with ATCA/CABB • First systematic survey of CO(1-0) in unbiased sample of HzRGs. • Status (14 sample sources):: • - 6 sources observed • (tint ~15h per source) • 1 detection • 1 tentative detection • - 5 sources scheduled in • Aug/Sept CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  14. CO(1-0) survey of HzRG with ATCA/CABB • First systematic survey of CO(1-0) in unbiased sample of HzRGs. Compar • Status (14 sample sources):: • - 6 sources observed • (tint ~15h per source) • 1 detection • 1 tentative detection • - 5 sources scheduled in • Aug/Sept • CO(1-0) only detected in compact radio sources, • or outside the radio continuum (but low number statistics!) • - CO(1-0) – molecular gas least affected by excitation/heating – • at radii not affected by radio source?? • - Alignment CO(1-0) with radio jets? (e.g. Klamer et al 2004) • Compare with ongoing EVLA CO(1-0) surveys: • - high-z submm galaxies (Ivison et al. 2011) • - high-z starforming BzK galaxies (Aravena et al. 2010) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  15. ALMA Early-Science (cycle-0) • CO(6-5) in radio galaxy MRC 0152-209 • CO(6-5): fobs = 236 GHz (ALMA band 6) • Dense molecular gas in starburst/AGN region • 0.7” resolution (comparable to HST morphology) • Physical properties (density/temp) excitation ladder: CO(1-0) (ATCA) + CO(6-5) (ALMA) CO excitation ladder CO(6-5) Quasars SMG Peak Sν: 0.8 mJy/bm CO(1-0) Riechers et al. (2011) 400 km/s CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  16. ALMA Early-Science • CO(6-5) in radio galaxy MRC 0152-209 Dense molecular gas in starburst/AGN region CO excitation ladder Compar Quasars CO(1-0) (6-5) x10-30! • ALMA cycle-0: • tint = 1h (on-source) • fobs = 236 GHz • (band 6) • Δv = 50 km/s • σ = 0.6 mJy/bm 0.8 mJy/bm SMG CO(6-5) integrated signal at 13 - 40σ level Extended array – 0.7” res. (compact array -- 2.3”) Resolve CO(6-5) signal kinematically and spatially at ~6 kpc (19 kpc) Riechers et al. (2011) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  17. ALMA Early-Science • CO(6-5) in radio galaxy MRC 0152-209 Dense molecular gas in starburst/AGN region CO excitation ladder Compar Quasars CO(1-0) (6-5) x10-30! • ALMA cycle-0: • tint = 1h (on-source) • fobs = 236 GHz • (band 6) • Δv = 50 km/s • σ = 0.6 mJy/bm 0.8 mJy/bm SMG CO(6-5) integrated signal at 13 - 40σ level Extended array – 0.7” res. (compact array -- 2.3”) Resolve CO(6-5) signal kinematically and spatially at ~6 kpc (19 kpc) 15σ Riechers et al. (2011) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  18. Conclusions • ATCA/CABB crucial southern instrument for complementary studies of high-z CO with ALMA • CO(1-0) observations with ATCA/CABB: most robust tracer for molecular gas at high-z (incl low-density, widespread, sub-thermally excited component). • ATCA/CABB excellent mm spectral-line performance • Ongoing systematic survey of CO(1-0) in HzRG • MRC 0152-209: strongest CO(1-0) signal in HzRG to date • Ideal for ALMA observations of high CO transitions of dense molecular gas CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  19. ATCA/CABB • ATCA/CABB has overcome these limitations: • 4 (2x2) GHz instantaneous bandwidth • Observing frequencies < 50 GHz 3mm (84-105 GHz); 7mm (30-50 GHz); 15mm (16-25 GHz) • Hybrid array configurations with baselines as short as 31m. Example: CO(2-1) at z=5 fobf = 38 GHz (7mm band) Δv=15,000 km/s per 2 GHz! H75 hybrid array (ATCA - Narrabri, NSW) • Similar for EVLA/WIDAR • in the northern hemisphere • EVLA 27 vs ATCA 5/6 dishes; • ATCA H75: 15 baselines <100m • EVLA D-array: 41 baselines <100m • (12% of all baselines) • EVLA ‘E-array’ would be fantastic! • EVLA mm-observations only down to • dec ~ -25 deg CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

  20. CO(1-0) survey of HzRG with ATCA/CABB • CO(1-0) in z=1.92 radio galaxy MRC 0152-209 Pentericci et al. (2000, 2001) 83 kpc 8 kpc Emonts et al. (2011), ApJL accepted (arXiv/…..) CSIRO. ATCA/CABB CO(1-0) survey of HzRGs

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