The nature of Hβ+[O III] and [O II] emitters to z ∼ 5 with HiZELS: stellar mass functions and the evolution of EWs
Abstract
We investigate the properties of ∼7000 narrow-band selected galaxies with strong Hβ+[O III] and [O II] nebular emission lines from the High-z Emission-Line Survey between z ∼ 0.8 and 5.0. Our sample covers a wide range in stellar mass (M_(stellar) ∼ 10^(7.5–12.0) M_⊙), rest-frame equivalent widths (EW_(rest) ∼10–10^5 Å), and line luminosities (L_(line) ∼ 10^(40.5–43.2) erg s^(−1)). We measure the Hβ+[O III]-selected stellar mass functions out to z ∼ 3.5 and find that both M_⋆ and ϕ_⋆ increases with cosmic time. The [O II]-selected stellar mass functions show a constant M_⋆ ≈ 10^(11.6) M_⊙ and a strong, increasing evolution with cosmic time in ϕ_⋆ in line with Hα studies. We also investigate the evolution of the EW_(rest) as a function of redshift with a fixed mass range (10^(9.5–10.0) M_⊙) and find an increasing trend best represented by (1 + z)^(3.81 ± 0.14) and (1 + z)^(2.72 ± 0.19) up to z ∼ 2 and ∼3 for Hβ+[O III] and [O II] emitters, respectively. This is the first time that the EW_(rest) evolution has been directly measured for Hβ+[O III] and [O II] emitters up to these redshifts. There is evidence for a slower evolution for z > 2 in the Hβ+[O III] EW_(rest) and a decreasing trend for z > 3 in the [O II] EW_(rest) evolution, which would imply low [O II] EW at the highest redshifts and higher [O III]/[O II] line ratios. This suggests that the ionization parameter at higher redshift may be significantly higher than the local Universe. Our results set the stage for future near-IR space-based spectroscopic surveys to test our extrapolated predictions and also produce z > 5 measurements to constrain the high-z end of the EW_(rest) and [O III]/[O II] evolution.
Additional Information
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 August 24. Received 2016 August 24; in original form 2016. We thank the anonymous referee for their detailed comments and suggestions that improved this study. We also thank Anahita Alavi, Philip Best, Rychard Bouwens, Naveen Reddy, and Irene Shivaei for their insightful discussions and comments. The catalogues used in this analysis are publicly available from Sobral et al. (2013a). DS acknowledges financial support from the Netherlands Organization for Scientific research (NWO) through a Veni fellowship, from FCT through an FCT Investigator Starting Grant and Start-up Grant (IF/01154/2012/CP0189/CT0010) and from FCT grant PEst-OE/FIS/UI2751/2014. IRS acknowledges support from ST7C (ST/L00075X/1), the ERC Advanced Grant DUSTYGAL (321334) and a Royal Society/Wolfson Merit award. BD acknowledges financial support from NASA through the Astrophysics Data Analysis Program (ADAP), grant number NNX12AE20G. JPS gratefully acknowledges support from a Hintze Research Fellowship.Attached Files
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Additional details
- Eprint ID
- 75210
- Resolver ID
- CaltechAUTHORS:20170317-133235480
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- IF/01154/2012/CP0189/CT0010
- Fundação para a Ciência e a Tecnologia (FCT)
- PEst-OE/FIS/UI2751/2014
- Fundação para a Ciência e a Tecnologia (FCT)
- ST/L00075X/1
- Science and Technology Facilities Council (STFC)
- 321334
- European Research Council (ERC)
- Royal Society
- NNX12AE20G
- NASA
- Hintze Family Charitable Trust
- Created
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2017-03-17Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field