TRACING THE REIONIZATION EPOCH WITH ALMA: [C $\Tiny \text{II}$] EMISSION IN z ~ 7 GALAXIES
Authors
Pentericci, L.
Carniani, S.
Castellano, M.
Fontana, A.
Maiolino, R.
Guaita, L.
Vanzella, E.
Grazian, A.
Santini, P.
Yan, H.
Cristiani, S.
Conselice, C.
Giavalisco, M.
Hathi, N.
Koekemoer, A.
Publication Date
2016-09-19Journal Title
The Astrophysical Journal Letters
Publisher
IOP Science
Volume
829
Issue
1
Number
L11
Language
English
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Pentericci, L., Carniani, S., Castellano, M., Fontana, A., Maiolino, R., Guaita, L., Vanzella, E., et al. (2016). TRACING THE REIONIZATION EPOCH WITH ALMA: [C $\Tiny \text{II}$] EMISSION IN z ~ 7 GALAXIES. The Astrophysical Journal Letters, 829 (1. L11)https://doi.org/10.3847/2041-8205/829/1/L11
Description
This is the final version of the article. It first appeared from IOP Science via http://dx.doi.org/10.3847/2041-8205/829/1/L11
Abstract
We present new results on [C $\Tiny \text{II}$]158 $\mu$m emission from four galaxies in the reionization epoch. These galaxies were previously confirmed to be at redshifts between 6.6 and 7.15 from the presence of the Ly$\alpha$ emission line in their spectra. The Ly$\alpha$ emission line is redshifted by 100–200 km s$^{-1}$ compared to the systemic redshift given by the [C $\Tiny \text{II}$] line. These velocity offsets are smaller than what is observed in $z$ ~ 3 Lyman break galaxies (LBGs) with similar UV luminosities and emission line properties. Smaller velocity shifts reduce the visibility of Ly$\alpha$ and hence somewhat alleviate the need for a very neutral intergalactic medium at $z$ ~ 7 to explain the drop in the fraction of Ly$\alpha$ emitters observed at this epoch. The galaxies show [C $\Tiny \text{II}$] emission with $\small{L}$[C $\Tiny \text{II}$] = 0.6 - 1.6 $\times$ 10$^8\small{L}_{\odot}$: these luminosities place them consistently below the star formation rate (SFR)–$\small{L}$[C $\Tiny \text{II}$] relation observed for low-redshift star-forming and metal-poor galaxies and also below $z$ = 5.5 LBGs with similar SFRs. We argue that previous undetections of [C $\Tiny \text{II}$] in $z$ ~ 7 galaxies with similar or smaller SFRs are due to selection effects: previous targets were mostly strong Ly$\alpha$ emitters and therefore probably metal-poor systems, while our galaxies are more representative of the general high-redshift star-forming population.
Keywords
galaxies: evolution, galaxies: formation, galaxies: high-redshift
Sponsorship
Science and Technology Facilities Council
Embargo Lift Date
2100-01-01
Identifiers
External DOI: https://doi.org/10.3847/2041-8205/829/1/L11
This record's URL: https://www.repository.cam.ac.uk/handle/1810/260893