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arXiv · 1105.0739

Molecular CO(1-0) gas in the z~2 radio galaxy MRC 0152-209

B. H. C. Emonts·I. Feain·M. Y. Mao·R. P. Norris·G. Miley·R. D. Ekers·M. Villar-Martin·H. J. A. Rottgering·E. M. Sadler·G. Rees·R. Morganti·D. J. Saikia·T. A. Oosterloo·J. B. Stevens·C. N. Tadhunter
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Abstract

We report the detection of molecular CO(1-0) gas in the high-z radio galaxy MRC 0152-209 (z = 1.92) with the Australia Telescope Compact Array Broadband Backend (ATCA/CABB). This is the third known detection of CO(1-0) in a high-z radio galaxy to date. CO(1-0) is the most robust tracer of the overall molecular gas content (including the wide-spread, low-density and subthermally excited component), hence observations of CO(1-0) are crucial for studying galaxy evolution in the Early Universe. We derive L'(CO) = (6.6 +- 2.0) x 10^10 K km/s pc^2 for MRC 0152-209, which is comparable to that derived from CO(1-0) observations of several high-z submillimetre and starforming BzK galaxies. The CO(1-0) traces a total molecular hydrogen mass of M(H2) = 5 x 10^10 (alpha_x/0.8) Msun. MRC 0152-209 is an infra-red bright radio galaxy, in which a large reservoir of cold molecular gas has not (yet) been depleted by star formation or radio source feedback. Its compact radio source is reliably detected at 40 GHz and has a steep spectral index of alpha = -1.3 between 1.4 and 40 GHz (4-115 GHz in the galaxy's rest-frame). MRC 0152-209 is part of an ongoing systematic ATCA/CABB survey of CO(1-0) in high-z radio galaxies between 1.7 < z < 3.

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B. H. C. Emonts, I. Feain, M. Y. Mao, R. P. Norris, G. Miley, R. D. Ekers, M. Villar-Martin, H. J. A. Rottgering, E. M. Sadler, G. Rees, R. Morganti, D. J. Saikia, T. A. Oosterloo, J. B. Stevens, C. N. Tadhunter. 2011-05-04. Molecular CO(1-0) gas in the z~2 radio galaxy MRC 0152-209. https://doi.org/10.1088/2041-8205%2F734%2F1%2Fl25

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