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Abstract
Lyman alpha emitters (LAEs) in the Epoch of Reionization (EoR) offer
valuable probes of both early galaxy evolution and the process of
reionization itself; however, the exact evolution of their abundance and
the nature of their emission remain open questions. We combine samples
of 229 and 349 LAE candidates at z = 5.7 and z = 6.6,
respectively, from the SILVERRUSH narrowband survey with deep Low
Frequency Array (LOFAR) radio continuum observations in the European
Large Area Infrared Space Observatory Survey-North 1 (ELAIS-N1) field to
search for radio galaxies in the EoR and study the low-frequency radio
properties of z ≳ 5.7 LAE emitters. Our LOFAR observations reach an unprecedented noise level of ~20 μJy beam−1 at 150 MHz, and we detect five candidate LAEs at >5σ
significance. Based on detailed spectral energy distribution modelling
of independent multi-wavelength observations in the field, we conclude
that these sources are likely [OII] emitters at z = 1.47, yielding no reliable z ≳ 5.7 radio galaxy candidates. We examine the 111 z = 5.7 and z
= 6.6 LAE candidates from our panchromatic photometry catalogue that
are undetected by LOFAR, finding contamination rates of 81–92% for the z = 5.7 and z
= 6.6 subset of the LAE candidate samples. This subset of the full
sample is biased towards brighter magnitudes and redder near-infrared
colours. The contamination rates of the full sample will therefore
likely be lower than the reported values. Contamination of these
optically bright LAE samples by likely [OII]
emitters is lowered significantly through constraints on the
near-infrared colours, highlighting the need for infrared observations
to robustly identify bright LAEs in narrowband surveys. Finally, the
stacking of radio continuum observations for the robust LAE samples
yields 2σ upper limits on radio luminosity of 8.2 × 1023 and 8.7 × 1023 W Hz−1 at z = 5.7 and 6.6, respectively, corresponding to limits on their median star-formation rates of <53 and <56 M⊙ yr−1.
Original language | English |
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Article number | A7 |
Pages (from-to) | 1-17 |
Number of pages | 17 |
Journal | Astronomy and Astrophysics |
Volume | 648 |
DOIs | |
Publication status | Published - 7 Apr 2021 |
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Dive into the research topics of 'LOFAR Properties of SILVERRUSH Lyα Emitter Candidates in the ELAIS-N1 Field'. Together they form a unique fingerprint.Projects
- 1 Finished
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Astronomy and Astrophysics at Edinburgh
Taylor, A., Best, P., Biller, B., Dunlop, J., Ivison, R., Khochfar, S., McLure, R. & Meiksin, A.
1/04/18 → 31/03/21
Project: Research