Strong [CII] emission at high redshift
Abstract
We report the detection of the [Cii]157.74 μm fine-structure line in the lensed galaxy BRI 0952-0115 at z=4.43, using the APEX telescope. This is the first detection of the [Cii] line in a source with L_FIR < 1013~L_⊙ at high redshift. The line is much stronger than previous [Cii] detections at high-z (a factor of 5-8 higher in flux), partly due to the lensing amplification. The L_[CII]/L_FIR ratio is 10-2.9, which is higher than observed in local galaxies with similar infrared luminosities. Together with previous observations of [Cii] at high redshift, our result suggests that the [Cii] emission in high-redshift galaxies is enhanced relative to local galaxies with the same infrared luminosity. This finding may result from selection effects of the few current observations of [Cii] at high redshift and, in particular, from non detections that may not have been published (although the few published upper limits are still consistent with the [Cii] enhancement scenario). If the trend is confirmed with larger samples, it would indicate that high-z galaxies are characterized by different physical conditions than for their local counterparts. Regardless of the physical origin of the trend, this effect would increase the potential of the [Cii]158 μm line to search and characterize high-z sources.
Based on observations made with ESO telescope APEX, under program ID E-082.B-0692A-2008. Appendix A is only available in electronic form at http://www.aanda.org- Publication:
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Astronomy and Astrophysics
- Pub Date:
- June 2009
- DOI:
- 10.1051/0004-6361/200912265
- arXiv:
- arXiv:0904.3793
- Bibcode:
- 2009A&A...500L...1M
- Keywords:
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- galaxies: high-redshift;
- galaxies: ISM;
- submillimeter;
- infrared: galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in A&