[O ii] emitters at z ∼ 4.6 in the GOODS field: a homogeneous measure of evolving star formation
Article first published online: 10 OCT 2012
© 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS
Monthly Notices of the Royal Astronomical Society
Volume 426, Issue 3, pages 2178–2188, 1 November 2012
How to Cite
Bayliss, K. D., McMahon, R. G., Venemans, B. P., Banerji, M. and Lewis, J. R. (2012), [O ii] emitters at z ∼ 4.6 in the GOODS field: a homogeneous measure of evolving star formation. Monthly Notices of the Royal Astronomical Society, 426: 2178–2188. doi: 10.1111/j.1365-2966.2012.21683.x
- Issue published online: 8 OCT 2012
- Article first published online: 10 OCT 2012
- Manuscript Accepted: 7 JUL 2012
- Manuscript Received: 7 JUL 2012
- galaxies: distances and redshifts;
- galaxies: high-redshift;
- galaxies: luminosity function, mass function;
- galaxies: star formation
We present the results of a high-redshift, z = 4.6, survey of [O ii] λ3727 emission line galaxies in the GOODS-S field. The survey uses deep near-infrared data in the NB2090 (λc = 2.095 μm, Δ λ = 0.02 μm) and Ks (λc = 2.146 μm, Δ λ = 0.324 μm) filters taken with the European Southern Observatory instrument, HAWK-I. The images reach an emission line flux limit (5σ) of 3.16 × 10−18 erg s−1 cm −2. At z = 4.6, the survey probes a comoving volume of ∼6680 Mpc3.
Three [O ii] emission line candidates at z ∼ 4.6 are selected using the Lyman-break criteria. Photometric redshift analysis supports the conclusion that these are genuine [O ii] emitters, ruling out a z < 3 solution entirely for one of the candidates. In the analysis presented in this paper, two scenarios are considered: first, all three candidates are genuine [O ii] emitters and secondly, only the most likely candidate is a genuine [O ii] emitter.
We use the line fluxes of these objects to place confidence limits on the star formation rate density (SFRD) in bright (log( [O ii] emission line galaxies. Assuming an observed [O ii]/Hα line ratio of 0.45 and A(Hα) = 1.0 mag, we report an SFRD of in our objects. Using small number statistics, we then place a 50 per cent confidence interval on the global star formation rate of . By combining our results with those from low-z surveys, we compile the first homogeneous set of measurements of the SFRD in bright [O ii] emitters from z = 0 to 4.6. From this, we conclude that there was an increase in the SFRD in the brightest [O ii] emitters of at least a factor of 2 between z = 4.6 and 1.85.