---
_id: '11566'
abstract:
- lang: eng
  text: While traditionally associated with active galactic nuclei (AGN), the properties
    of the C II] (λ = 2326 Å), C III] (λ, λ = 1907, 1909 Å) and C IV (λ, λ = 1549,
    1551 Å) emission lines are still uncertain as large, unbiased samples of sources
    are scarce. We present the first blind, statistical study of C II], C III] and
    C IV emitters at z ∼ 0.68, 1.05, 1.53, respectively, uniformly selected down to
    a flux limit of ∼4 × 10−17 erg s−1 cm−1 through a narrow-band survey covering
    an area of ∼1.4 deg2 over COSMOS and UDS. We detect 16 C II], 35 C III] and 17
    C IV emitters, whose nature we investigate using optical colours as well as Hubble
    Space Telescope (HST), X-ray, radio and far-infrared data. We find that z ∼ 0.7
    C II] emitters are consistent with a mixture of blue (UV slope β = −2.0 ± 0.4)
    star-forming (SF) galaxies with discy HST structure and AGN with Seyfert-like
    morphologies. Bright C II] emitters have individual X-ray detections as well as
    high average black hole accretion rates (BHARs) of ∼0.1 M⊙ yr−1. C III] emitters
    at z ∼ 1.05 trace a general population of SF galaxies, with β = −0.8 ± 1.1, a
    variety of optical morphologies, including isolated and interacting galaxies and
    low BHAR (<0.02 M⊙ yr−1). Our C IV emitters at z ∼ 1.5 are consistent with young,
    blue quasars (β ∼ −1.9) with point-like optical morphologies, bright X-ray counterparts
    and large BHAR (0.8  M⊙ yr−1). We also find some surprising C II], C III] and
    C IV emitters with rest-frame equivalent widths (EWs) that could be as large as
    50–100 Å. AGN or spatial offsets between the UV continuum stellar disc and the
    line-emitting regions may explain the large EW. These bright C II], C III] and
    C IV emitters are ideal candidates for spectroscopic follow-up to fully unveil
    their nature.
acknowledgement: 'We would like to thank the anonymous referee for her/his valuable
  input that helped improve the clarity and interpretation of our results. DS acknowledges
  financial support from the Netherlands Organisation for Scientific research (NWO),
  through a Veni fellowship. IO acknowledges support from the European Research Council
  in the form of the Advanced Investigator Programme, 321302, COSMICISM. CALYMHA data
  are based on observations made with the Isaac Newton Telescope (proposals 13AN002,
  I14AN002, 088-INT7/14A, I14BN006, 118-INT13/14B, I15AN008) operated on the island
  of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los
  Muchachos of the Instituto de Astrofísica de Canarias. Also based on data products
  from observations made with ESO Telescopes at the La Silla Paranal Observatory under
  ESO programme IDs 098.A-0819 and 179.A-2005. We are grateful to E. L. Wright and
  J. Schombert for their cosmology calculator. We would like to thank the authors
  of NUMPY (van der Walt et al. 2011), SCIPY (Jones et al. 2001), MATPLOTLIB (Hunter
  2007) and ASTROPY (Astropy Collaboration et al. 2013) for making these packages
  publicly available. This research has made use of the NASA/IPAC Extragalactic Database
  (NED), which is '
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Andra
  full_name: Stroe, Andra
  last_name: Stroe
- first_name: David
  full_name: Sobral, David
  last_name: Sobral
- first_name: Jorryt J
  full_name: Matthee, Jorryt J
  id: 7439a258-f3c0-11ec-9501-9df22fe06720
  last_name: Matthee
  orcid: 0000-0003-2871-127X
- first_name: João
  full_name: Calhau, João
  last_name: Calhau
- first_name: Ivan
  full_name: Oteo, Ivan
  last_name: Oteo
citation:
  ama: Stroe A, Sobral D, Matthee JJ, Calhau J, Oteo I. A 1.4 deg2 blind survey for
    C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature, morphologies and equivalent
    widths . <i>Monthly Notices of the Royal Astronomical Society</i>. 2017;471(3):2558-2574.
    doi:<a href="https://doi.org/10.1093/mnras/stx1712">10.1093/mnras/stx1712</a>
  apa: Stroe, A., Sobral, D., Matthee, J. J., Calhau, J., &#38; Oteo, I. (2017). A
    1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature, morphologies
    and equivalent widths . <i>Monthly Notices of the Royal Astronomical Society</i>.
    Oxford University Press. <a href="https://doi.org/10.1093/mnras/stx1712">https://doi.org/10.1093/mnras/stx1712</a>
  chicago: Stroe, Andra, David Sobral, Jorryt J Matthee, João Calhau, and Ivan Oteo.
    “A 1.4 Deg2 Blind Survey for C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature,
    Morphologies and Equivalent Widths .” <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press, 2017. <a href="https://doi.org/10.1093/mnras/stx1712">https://doi.org/10.1093/mnras/stx1712</a>.
  ieee: A. Stroe, D. Sobral, J. J. Matthee, J. Calhau, and I. Oteo, “A 1.4 deg2 blind
    survey for C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature, morphologies and
    equivalent widths ,” <i>Monthly Notices of the Royal Astronomical Society</i>,
    vol. 471, no. 3. Oxford University Press, pp. 2558–2574, 2017.
  ista: Stroe A, Sobral D, Matthee JJ, Calhau J, Oteo I. 2017. A 1.4 deg2 blind survey
    for C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature, morphologies and equivalent
    widths . Monthly Notices of the Royal Astronomical Society. 471(3), 2558–2574.
  mla: Stroe, Andra, et al. “A 1.4 Deg2 Blind Survey for C II], C III] and C IV at
    z ∼ 0.7–1.5 – I. Nature, Morphologies and Equivalent Widths .” <i>Monthly Notices
    of the Royal Astronomical Society</i>, vol. 471, no. 3, Oxford University Press,
    2017, pp. 2558–74, doi:<a href="https://doi.org/10.1093/mnras/stx1712">10.1093/mnras/stx1712</a>.
  short: A. Stroe, D. Sobral, J.J. Matthee, J. Calhau, I. Oteo, Monthly Notices of
    the Royal Astronomical Society 471 (2017) 2558–2574.
date_created: 2022-07-12T12:33:16Z
date_published: 2017-11-01T00:00:00Z
date_updated: 2022-08-19T07:59:57Z
day: '01'
doi: 10.1093/mnras/stx1712
extern: '1'
external_id:
  arxiv:
  - '1703.10169'
fulldoi: https://doi.org/10.1093/mnras/stx1712
intvolume: '       471'
issue: '3'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: active'
- 'galaxies: high-redshift'
- 'quasars: emission lines'
- 'galaxies: star formation'
- 'cosmology: observations'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1703.10169
month: '11'
oa: 1
oa_version: Preprint
page: 2558-2574
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  eissn:
  - 1365-2966
  issn:
  - 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'A 1.4 deg2 blind survey for C II], C III] and C IV at z ∼ 0.7–1.5 – I. Nature,
  morphologies and equivalent widths '
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 471
year: '2017'
...