Volume 530, June 2011
|Number of page(s)||4|
|Published online||13 May 2011|
Letter to the Editor
Enhanced [CII] emission in a z = 4.76 submillimetre galaxy
European Southern Observatory, Karl Schwarzschild Straße 2, 85748 Garching, Germany
2 INAF – Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone, Italy
3 School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
4 Department of Physics, McGill University, Ernest Rutherford Building, 3600 Rue University, Montréal, Québec, H3A 2T8, Canada
5 Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstraße 1, 85748 Garching, Germany
6 Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan
Received: 11 March 2011
Accepted: 27 April 2011
We present the detection of bright [CII] emission in the z = 4.76 submillimetre galaxy LESS J033229.4-275619 using the Atacama Pathfinder EXperiment. This represents the highest redshift [CII] detection in a submm selected, star-formation dominated system. The AGN contributions to the [CII] and far-infrared (FIR) luminosities are small. We find an atomic mass derived from [CII] comparable to the molecular mass derived from CO. The ratio of the [CII], CO and FIR luminosities imply a radiation field strength G0 ~ 103 and a density ~ 104 cm-3 in a kpc-scale starburst, as seen in local and high redshift starbursts. The high L [CII] /LFIR = 2.4 × 10-3 and the very high L [CII] /LCO(1 − 0) ≈ 104 are reminiscent of low metallicity dwarf galaxies, suggesting that the highest redshift star-forming galaxies may also be characterised by lower metallicities. We discuss the implications of a reduced metallicity on studies of the gas reservoirs, and conclude that especially at very high redshift, [CII] may be a more powerful and reliable tracer of the interstellar matter than CO.
Key words: galaxies: high-redshift / galaxies: ISM / submillimeter: galaxies / infrared: galaxies
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.