On the nature of H$α$ emitters at $z \sim 2$ from the HiZELS survey:physical properties, Ly$α$ escape fraction, and main sequence

Oteo, I. and Sobral, D. and Ivison, R. J. and Smail, I. and Best, P. N. and Cepa, J. and Perez-Garcia, A. M. (2015) On the nature of H$α$ emitters at $z \sim 2$ from the HiZELS survey:physical properties, Ly$α$ escape fraction, and main sequence. Monthly Notices of the Royal Astronomical Society, 452 (2). pp. 2018-2033. ISSN 0035-8711

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Abstract

We present a detailed multi-wavelength study (from rest-frame UV to far-IR) of narrow-band (NB) selected, star-forming (SF) H$\alpha$ emitters (HAEs) at $z \sim 2.23$ taken from the High Redshift(Z) Emission Line Survey (HiZELS). We find that HAEs have similar SED-derived properties and colors to $sBzK$ galaxies and probe a well-defined portion of the SF population at $z \sim 2$. This is not true for Ly$\alpha$ emitters (LAEs), which are strongly biased towards blue, less massive galaxies (missing a significant percentage of the SF population). Combining our H$\alpha$ observations with matched, existing Ly$\alpha$ data we determine that the Ly$\alpha$ escape fraction ($f_{\rm esc}$) is low (only $\sim$ 4.5\% of HAEs show Ly$\alpha$ emission) and decreases with increasing dust attenuation, UV continuum slope, stellar mass, and star formation rate (SFR). This suggests that Ly$\alpha$ preferentially escapes from blue galaxies with low dust attenuation. However, a small population of red and massive LAEs is also present in agreement with previous works. This indicates that dust and Ly$\alpha$ are not mutually exclusive. Using different and completely independent measures of the total SFR we show that the H$\alpha$ emission is an excellent tracer of star formation at $z \sim 2$ with deviations typically lower than 0.3 dex for individual galaxies. We find that the slope and zero-point of the HAE main-sequence (MS) at $z \sim 2$ strongly depend on the dust correction method used to recover SFR, although they are consistent with previous works when similar assumptions are made.

Item Type:
Journal Article
Journal or Publication Title:
Monthly Notices of the Royal Astronomical Society
Additional Information:
This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version I. Oteo, D. Sobral, R. J. Ivison, I. Smail, P. N. Best, J. Cepa, and A. M. Pérez-García On the nature of Hα emitters at z~ 2 from the HiZELS survey: physical properties, Lyα escape fraction and main sequence MNRAS 2015 452: 2018-2033. is available online at: http://mnras.oxfordjournals.org/content/452/2/2018
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
ID Code:
77524
Deposited By:
Deposited On:
20 Jan 2016 11:56
Refereed?:
Yes
Published?:
Published
Last Modified:
11 Jul 2020 05:36