---
_id: '11530'
abstract:
- lang: eng
  text: A prediction of the classic active galactic nucleus (AGN) unification model
    is the presence of ionization cones with different orientations depending on the
    AGN type. Confirmations of this model exist for present times, but it is less
    clear in the early Universe. Here, we use the morphology of giant Ly α nebulae
    around AGNs at redshift z ∼ 3 to probe AGN emission and therefore the validity
    of the AGN unification model at this redshift. We compare the spatial morphology
    of 19 nebulae previously found around type I AGNs with a new sample of four Ly α
    nebulae detected around type II AGNs. Using two independent techniques, we find
    that nebulae around type II AGNs are more asymmetric than around type I, at least
    at radial distances r > 30 physical kpc (pkpc) from the ionizing source. We conclude
    that the type I and type II AGNs in our sample show evidence of different surrounding
    ionizing geometries. This suggests that the classical AGN unification model is
    also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry
    in the inner parts (r ≲ 30 pkpc) and the associated high values of the He II to
    Ly α ratios in these regions could indicate additional sources of (hard) ionizing
    radiation originating within or in proximity of the AGN host galaxies. This work
    demonstrates that the morphologies of giant Ly α nebulae can be used to understand
    and study the geometry of high-redshift AGNs on circumnuclear scales and it lays
    the foundation for future studies using much larger statistical samples.
acknowledgement: SC and GP gratefully acknowledge support from Swiss National Science
  Foundation grant PP00P2 163824. MK acknowledges support by DLR500R1904.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: J S
  full_name: den Brok, J S
  last_name: den Brok
- first_name: S
  full_name: Cantalupo, S
  last_name: Cantalupo
- first_name: R
  full_name: Mackenzie, R
  last_name: Mackenzie
- first_name: R A
  full_name: Marino, R A
  last_name: Marino
- first_name: G
  full_name: Pezzulli, G
  last_name: Pezzulli
- 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: S D
  full_name: Johnson, S D
  last_name: Johnson
- first_name: M
  full_name: Krumpe, M
  last_name: Krumpe
- first_name: T
  full_name: Urrutia, T
  last_name: Urrutia
- first_name: W
  full_name: Kollatschny, W
  last_name: Kollatschny
citation:
  ama: den Brok JS, Cantalupo S, Mackenzie R, et al. Probing the AGN unification model
    at redshift z ∼ 3 with MUSE observations of giant Lyα nebulae. <i>Monthly Notices
    of the Royal Astronomical Society</i>. 2020;495(2):1874-1887. doi:<a href="https://doi.org/10.1093/mnras/staa1269">10.1093/mnras/staa1269</a>
  apa: den Brok, J. S., Cantalupo, S., Mackenzie, R., Marino, R. A., Pezzulli, G.,
    Matthee, J. J., … Kollatschny, W. (2020). Probing the AGN unification model at
    redshift z ∼ 3 with MUSE observations of giant Lyα nebulae. <i>Monthly Notices
    of the Royal Astronomical Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/staa1269">https://doi.org/10.1093/mnras/staa1269</a>
  chicago: den Brok, J S, S Cantalupo, R Mackenzie, R A Marino, G Pezzulli, Jorryt
    J Matthee, S D Johnson, M Krumpe, T Urrutia, and W Kollatschny. “Probing the AGN
    Unification Model at Redshift z ∼ 3 with MUSE Observations of Giant Lyα Nebulae.”
    <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press,
    2020. <a href="https://doi.org/10.1093/mnras/staa1269">https://doi.org/10.1093/mnras/staa1269</a>.
  ieee: J. S. den Brok <i>et al.</i>, “Probing the AGN unification model at redshift
    z ∼ 3 with MUSE observations of giant Lyα nebulae,” <i>Monthly Notices of the
    Royal Astronomical Society</i>, vol. 495, no. 2. Oxford University Press, pp.
    1874–1887, 2020.
  ista: den Brok JS, Cantalupo S, Mackenzie R, Marino RA, Pezzulli G, Matthee JJ,
    Johnson SD, Krumpe M, Urrutia T, Kollatschny W. 2020. Probing the AGN unification
    model at redshift z ∼ 3 with MUSE observations of giant Lyα nebulae. Monthly Notices
    of the Royal Astronomical Society. 495(2), 1874–1887.
  mla: den Brok, J. S., et al. “Probing the AGN Unification Model at Redshift z ∼
    3 with MUSE Observations of Giant Lyα Nebulae.” <i>Monthly Notices of the Royal
    Astronomical Society</i>, vol. 495, no. 2, Oxford University Press, 2020, pp.
    1874–87, doi:<a href="https://doi.org/10.1093/mnras/staa1269">10.1093/mnras/staa1269</a>.
  short: J.S. den Brok, S. Cantalupo, R. Mackenzie, R.A. Marino, G. Pezzulli, J.J.
    Matthee, S.D. Johnson, M. Krumpe, T. Urrutia, W. Kollatschny, Monthly Notices
    of the Royal Astronomical Society 495 (2020) 1874–1887.
date_created: 2022-07-07T10:40:17Z
date_published: 2020-06-01T00:00:00Z
date_updated: 2022-08-18T11:17:47Z
day: '01'
doi: 10.1093/mnras/staa1269
extern: '1'
external_id:
  arxiv:
  - '2005.01732'
intvolume: '       495'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: active'
- 'galaxies: high-redshift'
- intergalactic medium
- 'quasars: emission lines'
- 'quasars: general'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/2005.01732
month: '06'
oa: 1
oa_version: Preprint
page: 1874-1887
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: Probing the AGN unification model at redshift z ∼ 3 with MUSE observations
  of giant Lyα nebulae
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 495
year: '2020'
...
---
_id: '11539'
abstract:
- lang: eng
  text: 'Despite recent progress in understanding Ly α emitters (LAEs), relatively
    little is known regarding their typical black hole activity across cosmic time.
    Here, we study the X-ray and radio properties of ∼4000 LAEs at 2.2 < z < 6 from
    the SC4K survey in the COSMOS field. We detect 254 (⁠6.8per cent±0.4per cent⁠)
    LAEs individually in the X-rays (S/N > 3) with an average luminosity of 1044.31±0.01ergs−1
    and average black hole accretion rate (BHAR) of 0.72±0.01 M⊙ yr−1, consistent
    with moderate to high accreting active galactic neuclei (AGNs). We detect 120
    sources in deep radio data (radio AGN fraction of 3.2per cent±0.3per cent⁠). The
    global AGN fraction (⁠8.6per cent±0.4per cent⁠) rises with Ly α luminosity and
    declines with increasing redshift. For X-ray-detected LAEs, Ly α luminosities
    correlate with the BHARs, suggesting that Ly α luminosity becomes a BHAR indicator.
    Most LAEs (⁠93.1per cent±0.6per cent⁠) at 2 < z < 6 have no detectable X-ray emission
    (BHARs < 0.017 M⊙ yr−1). The median star formation rate (SFR) of star-forming
    LAEs from Ly α and radio luminosities is 7.6+6.6−2.8 M⊙ yr−1. The black hole to
    galaxy growth ratio (BHAR/SFR) for LAEs is <0.0022, consistent with typical star-forming
    galaxies and the local BHAR/SFR relation. We conclude that LAEs at 2 < z < 6 include
    two different populations: an AGN population, where Ly α luminosity traces BHAR,
    and another with low SFRs which remain undetected in even the deepest X-ray stacks
    but is detected in the radio stacks.'
acknowledgement: JM acknowledges the support of a Huygens PhD fellowship from Leiden
  University. We thank Camila Correa for help analysing snipshot merger trees. We
  thank the anonymous referee for constructive comments. We also thank Jarle Brinchmann,
  Rob Crain, Antonios Katsianis, Paola Popesso, and David Sobral for discussions and
  suggestions. We also thank the participants of the Lorentz Center workshop ‘A Decade
  of the Star-Forming Main Sequence’ held on 2017 September 4–8, for discussions and
  ideas. We have benefited from the public available programming language PYTHON,
  including the NUMPY, MATPLOTLIB, and SCIPY (Hunter 2007) packages and the TOPCAT
  analysis tool (Taylor 2013).
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: João
  full_name: Calhau, João
  last_name: Calhau
- first_name: David
  full_name: Sobral, David
  last_name: Sobral
- first_name: Sérgio
  full_name: Santos, Sérgio
  last_name: Santos
- 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: Ana
  full_name: Paulino-Afonso, Ana
  last_name: Paulino-Afonso
- first_name: Andra
  full_name: Stroe, Andra
  last_name: Stroe
- first_name: Brooke
  full_name: Simmons, Brooke
  last_name: Simmons
- first_name: Cassandra
  full_name: Barlow-Hall, Cassandra
  last_name: Barlow-Hall
- first_name: Benjamin
  full_name: Adams, Benjamin
  last_name: Adams
citation:
  ama: 'Calhau J, Sobral D, Santos S, et al. The X-ray and radio activity of typical
    and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving
    population. <i>Monthly Notices of the Royal Astronomical Society</i>. 2020;493(3):3341-3362.
    doi:<a href="https://doi.org/10.1093/mnras/staa476">10.1093/mnras/staa476</a>'
  apa: 'Calhau, J., Sobral, D., Santos, S., Matthee, J. J., Paulino-Afonso, A., Stroe,
    A., … Adams, B. (2020). The X-ray and radio activity of typical and luminous Ly α
    emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population. <i>Monthly
    Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/staa476">https://doi.org/10.1093/mnras/staa476</a>'
  chicago: 'Calhau, João, David Sobral, Sérgio Santos, Jorryt J Matthee, Ana Paulino-Afonso,
    Andra Stroe, Brooke Simmons, Cassandra Barlow-Hall, and Benjamin Adams. “The X-Ray
    and Radio Activity of Typical and Luminous Ly α Emitters from z ∼ 2 to z ∼ 6:
    Evidence for a Diverse, Evolving Population.” <i>Monthly Notices of the Royal
    Astronomical Society</i>. Oxford University Press, 2020. <a href="https://doi.org/10.1093/mnras/staa476">https://doi.org/10.1093/mnras/staa476</a>.'
  ieee: 'J. Calhau <i>et al.</i>, “The X-ray and radio activity of typical and luminous
    Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population,”
    <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 493, no. 3. Oxford
    University Press, pp. 3341–3362, 2020.'
  ista: 'Calhau J, Sobral D, Santos S, Matthee JJ, Paulino-Afonso A, Stroe A, Simmons
    B, Barlow-Hall C, Adams B. 2020. The X-ray and radio activity of typical and luminous
    Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population.
    Monthly Notices of the Royal Astronomical Society. 493(3), 3341–3362.'
  mla: 'Calhau, João, et al. “The X-Ray and Radio Activity of Typical and Luminous
    Ly α Emitters from z ∼ 2 to z ∼ 6: Evidence for a Diverse, Evolving Population.”
    <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 493, no. 3, Oxford
    University Press, 2020, pp. 3341–62, doi:<a href="https://doi.org/10.1093/mnras/staa476">10.1093/mnras/staa476</a>.'
  short: J. Calhau, D. Sobral, S. Santos, J.J. Matthee, A. Paulino-Afonso, A. Stroe,
    B. Simmons, C. Barlow-Hall, B. Adams, Monthly Notices of the Royal Astronomical
    Society 493 (2020) 3341–3362.
date_created: 2022-07-08T07:34:10Z
date_published: 2020-04-01T00:00:00Z
date_updated: 2022-08-18T11:25:31Z
day: '01'
doi: 10.1093/mnras/staa476
extern: '1'
external_id:
  arxiv:
  - '1909.11672'
intvolume: '       493'
issue: '3'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: active'
- 'galaxies: evolution'
- 'galaxies: high-redshift'
- 'quasars: supermassive black holes'
- 'galaxies: star formation'
- 'cosmology: observations'
- 'X-rays: galaxies'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1909.11672
month: '04'
oa: 1
oa_version: Preprint
page: 3341-3362
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: 'The X-ray and radio activity of typical and luminous Ly α emitters from z
  ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 493
year: '2020'
...
---
_id: '11557'
abstract:
- lang: eng
  text: Deep narrow-band surveys have revealed a large population of faint Ly α emitters
    (LAEs) in the distant Universe, but relatively little is known about the most
    luminous sources (⁠LLyα≳1042.7 erg s−1; LLyα≳L∗Lyα⁠). Here we present the spectroscopic
    follow-up of 21 luminous LAEs at z ∼ 2–3 found with panoramic narrow-band surveys
    over five independent extragalactic fields (≈4 × 106 Mpc3 surveyed at z ∼ 2.2
    and z ∼ 3.1). We use WHT/ISIS, Keck/DEIMOS, and VLT/X-SHOOTER to study these sources
    using high ionization UV lines. Luminous LAEs at z ∼ 2–3 have blue UV slopes (⁠β=−2.0+0.3−0.1⁠)
    and high Ly α escape fractions (⁠50+20−15 per cent) and span five orders of magnitude
    in UV luminosity (MUV ≈ −19 to −24). Many (70 per cent) show at least one high
    ionization rest-frame UV line such as C IV, N V, C III], He II or O III], typically
    blue-shifted by ≈100–200 km s−1 relative to Ly α. Their Ly α profiles reveal a
    wide variety of shapes, including significant blue-shifted components and widths
    from 200 to 4000 km s−1. Overall, 60 ± 11  per cent appear to be active galactic
    nucleus (AGN) dominated, and at LLyα > 1043.3 erg s−1 and/or MUV < −21.5 virtually
    all LAEs are AGNs with high ionization parameters (log U = 0.6 ± 0.5) and with
    metallicities of ≈0.5 − 1 Z⊙. Those lacking signatures of AGNs (40 ± 11  per cent)
    have lower ionization parameters (⁠logU=−3.0+1.6−0.9 and log ξion = 25.4 ± 0.2)
    and are apparently metal-poor sources likely powered by young, dust-poor ‘maximal’
    starbursts. Our results show that luminous LAEs at z ∼ 2–3 are a diverse population
    and that 2×L∗Lyα and 2×M∗UV mark a sharp transition in the nature of LAEs, from
    star formation dominated to AGN dominated.
acknowledgement: 'We thank the anonymous reviewer for their timely and constructive
  comments that greatly helped us to improve the manuscript. DS acknowledges financial
  support from the Netherlands Organization for Scientific research (NWO) through
  a Veni fellowship and from Lancaster University through an Early Career Internal
  Grant A100679. JM acknowledges the support of a Huygens PhD fellowship from Leiden
  University. BD acknowledges financial support from NASA through the Astrophysics
  Data Analysis Program (ADAP), grant number NNX12AE20G, and the National Science
  Foundation, grant number 1716907. IRS acknowledges support from the ERC Advanced
  Grant DUSTYGAL (321334), STFC (ST/P000541/1), and a Royal Society/Wolfson Merit
  Award. PNB is grateful for support from STFC via grant ST/M001229/1. We thank Anne
  Verhamme, Kimihiko Nakajima, Ryan Trainor, Sangeeta Malhotra, Max Gronke, James
  Rhoads, Fang Xia An, Matthew Hayes, Takashi Kojima, Mark Dijkstra, and Anne Jaskot
  for many helpful and engaging discussions, particularly during the SnowCLAW Ly α
  workshop. We thank Bruno Ribeiro, Stephane Charlot, and Joseph Caruana for comments
  on the manuscript. The authors would also like to thank Ingrid Tengs, Meg Singleton,
  Ali Khostovan, and Sara Perez for participating in part of the observations. We
  also thank Joao Calhau, Leah Morabito, Sergio Santos, and Aayush Saxena for their
  assistance with the narrow-band observations which allowed to select some of the
  sour ces. Based on observations obtained with the William Herschel Telescope, program:
  W16AN004; the Very Large Telescope, programs: 098.A-0819 & 099.A-0254; and the Keck
  II telescope, program: C267D. Based on data products from observations made with
  ESO Telescopes at the La Silla Paranal Observatory under ESO programme IDs 294.A-5018,
  294.A-5039, 092.A-0786, 093.A-0561, 097.A-0943, 098.A-0819, 099.A-0254 and 179.A-2005.
  The authors acknowledge the award of service time (SW2014b20) on the WHT. WHT and
  its service programme are 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
  Astrofisica de Canarias. The authors would also like to thank all the extremely
  helpful observatory staff that have greatly contributed towards our observations,
  particularly Fiona Riddick, Lilian Dominguez, Florencia Jimenez, and Ian Skillen.
  We have benefited greatly from the publicly available programming language PYTHON,
  including the NUMPY & SCIPY (Van Der Walt, Colbert & Varoquaux 2011; Jones et al.
  2001), MATPLOTLIB (Hunter 2007), ASTROPY (Astropy Collaboration et al. 2013), and
  the TOPCAT analysis program (Taylor 2013). This research has made use of the VizieR
  catalogue access tool, CDS, Strasbourg, France.'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- 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: Behnam
  full_name: Darvish, Behnam
  last_name: Darvish
- first_name: Ian
  full_name: Smail, Ian
  last_name: Smail
- first_name: Philip N
  full_name: Best, Philip N
  last_name: Best
- first_name: Lara
  full_name: Alegre, Lara
  last_name: Alegre
- first_name: Huub
  full_name: Röttgering, Huub
  last_name: Röttgering
- first_name: Bahram
  full_name: Mobasher, Bahram
  last_name: Mobasher
- first_name: Ana
  full_name: Paulino-Afonso, Ana
  last_name: Paulino-Afonso
- first_name: Andra
  full_name: Stroe, Andra
  last_name: Stroe
- first_name: Iván
  full_name: Oteo, Iván
  last_name: Oteo
citation:
  ama: 'Sobral D, Matthee JJ, Darvish B, et al. The nature of luminous Ly α emitters
    at z ∼ 2–3: Maximal dust-poor starbursts and highly ionizing AGN. <i>Monthly Notices
    of the Royal Astronomical Society</i>. 2018;477(2):2817-2840. doi:<a href="https://doi.org/10.1093/mnras/sty782">10.1093/mnras/sty782</a>'
  apa: 'Sobral, D., Matthee, J. J., Darvish, B., Smail, I., Best, P. N., Alegre, L.,
    … Oteo, I. (2018). The nature of luminous Ly α emitters at z ∼ 2–3: Maximal dust-poor
    starbursts and highly ionizing AGN. <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/sty782">https://doi.org/10.1093/mnras/sty782</a>'
  chicago: 'Sobral, David, Jorryt J Matthee, Behnam Darvish, Ian Smail, Philip N Best,
    Lara Alegre, Huub Röttgering, et al. “The Nature of Luminous Ly α Emitters at
    z ∼ 2–3: Maximal Dust-Poor Starbursts and Highly Ionizing AGN.” <i>Monthly Notices
    of the Royal Astronomical Society</i>. Oxford University Press, 2018. <a href="https://doi.org/10.1093/mnras/sty782">https://doi.org/10.1093/mnras/sty782</a>.'
  ieee: 'D. Sobral <i>et al.</i>, “The nature of luminous Ly α emitters at z ∼ 2–3:
    Maximal dust-poor starbursts and highly ionizing AGN,” <i>Monthly Notices of the
    Royal Astronomical Society</i>, vol. 477, no. 2. Oxford University Press, pp.
    2817–2840, 2018.'
  ista: 'Sobral D, Matthee JJ, Darvish B, Smail I, Best PN, Alegre L, Röttgering H,
    Mobasher B, Paulino-Afonso A, Stroe A, Oteo I. 2018. The nature of luminous Ly
    α emitters at z ∼ 2–3: Maximal dust-poor starbursts and highly ionizing AGN. Monthly
    Notices of the Royal Astronomical Society. 477(2), 2817–2840.'
  mla: 'Sobral, David, et al. “The Nature of Luminous Ly α Emitters at z ∼ 2–3: Maximal
    Dust-Poor Starbursts and Highly Ionizing AGN.” <i>Monthly Notices of the Royal
    Astronomical Society</i>, vol. 477, no. 2, Oxford University Press, 2018, pp.
    2817–40, doi:<a href="https://doi.org/10.1093/mnras/sty782">10.1093/mnras/sty782</a>.'
  short: D. Sobral, J.J. Matthee, B. Darvish, I. Smail, P.N. Best, L. Alegre, H. Röttgering,
    B. Mobasher, A. Paulino-Afonso, A. Stroe, I. Oteo, Monthly Notices of the Royal
    Astronomical Society 477 (2018) 2817–2840.
date_created: 2022-07-12T07:18:02Z
date_published: 2018-06-01T00:00:00Z
date_updated: 2022-08-19T07:01:08Z
day: '01'
doi: 10.1093/mnras/sty782
extern: '1'
external_id:
  arxiv:
  - '1802.10102'
intvolume: '       477'
issue: '2'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: active'
- 'galaxies: evolution'
- 'galaxies: high-redshift'
- 'galaxies: ISM'
- 'galaxies: starburst'
- 'cosmology: observations'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1802.10102
month: '06'
oa: 1
oa_version: Preprint
page: 2817-2840
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: 'The nature of luminous Ly α emitters at z ∼ 2–3: Maximal dust-poor starbursts
  and highly ionizing AGN'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 477
year: '2018'
...
---
_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'
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'
...
---
_id: '11567'
abstract:
- lang: eng
  text: Recently, the C III] and C IV emission lines have been observed in galaxies
    in the early Universe (z > 5), providing new ways to measure their redshift and
    study their stellar populations and active galactic nuclei (AGN). We explore the
    first blind C II], C III] and C IV survey (z ∼ 0.68, 1.05, 1.53, respectively)
    presented in Stroe et al. (2017). We derive luminosity functions (LF) and study
    properties of C II], C III] and C IV line emitters through comparisons to the
    LFs of H α and Ly α emitters, UV selected star-forming (SF) galaxies and quasars
    at similar redshifts. The C II] LF at z ∼ 0.68 is equally well described by a
    Schechter or a power-law LF, characteristic of a mixture of SF and AGN activity.
    The C III] LF (z ∼ 1.05) is consistent to a scaled down version of the Schechter
    H α and Ly α LF at their redshift, indicating a SF origin. In stark contrast,
    the C IV LF at z ∼ 1.53 is well fit by a power-law, quasar-like LF. We find that
    the brightest UV sources (MUV < −22) will universally have C III] and C IV emission.
    However, on average, C III] and C IV are not as abundant as H α or Ly α emitters
    at the same redshift, with cosmic average ratios of ∼0.02–0.06 to H α and ∼0.01–0.1
    to intrinsic Ly α. We predict that the C III] and C IV lines can only be truly
    competitive in confirming high-redshift candidates when the hosts are intrinsically
    bright and the effective Ly α escape fraction is below 1 per cent. While C III]
    and C IV were proposed as good tracers of young, relatively low-metallicity galaxies
    typical of the early Universe, we find that, at least at z ∼ 1.5, C IV is exclusively
    hosted by AGN/quasars, especially at large line equivalent widths.
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 – II. Luminosity functions and cosmic average
    line ratios. <i>Monthly Notices of the Royal Astronomical Society</i>. 2017;471(3):2575-2586.
    doi:<a href="https://doi.org/10.1093/mnras/stx1713">10.1093/mnras/stx1713</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 – II. Luminosity
    functions and cosmic average line ratios. <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/stx1713">https://doi.org/10.1093/mnras/stx1713</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 – II. Luminosity
    Functions and Cosmic Average Line Ratios.” <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press, 2017. <a href="https://doi.org/10.1093/mnras/stx1713">https://doi.org/10.1093/mnras/stx1713</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 – II. Luminosity functions and
    cosmic average line ratios,” <i>Monthly Notices of the Royal Astronomical Society</i>,
    vol. 471, no. 3. Oxford University Press, pp. 2575–2586, 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 – II. Luminosity functions and cosmic
    average line ratios. Monthly Notices of the Royal Astronomical Society. 471(3),
    2575–2586.
  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 – II. Luminosity Functions and Cosmic Average Line Ratios.” <i>Monthly
    Notices of the Royal Astronomical Society</i>, vol. 471, no. 3, Oxford University
    Press, 2017, pp. 2575–86, doi:<a href="https://doi.org/10.1093/mnras/stx1713">10.1093/mnras/stx1713</a>.
  short: A. Stroe, D. Sobral, J.J. Matthee, J. Calhau, I. Oteo, Monthly Notices of
    the Royal Astronomical Society 471 (2017) 2575–2586.
date_created: 2022-07-12T12:54:57Z
date_published: 2017-11-01T00:00:00Z
date_updated: 2022-08-19T08:02:04Z
day: '01'
doi: 10.1093/mnras/stx1713
extern: '1'
external_id:
  arxiv:
  - '1703.10169'
intvolume: '       471'
issue: '3'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- 'galaxies: active'
- 'galaxies: high redshift'
- 'galaxies: luminosity function'
- mass function
- 'quasars: emission lines'
- 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: 2575-2586
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 – II. Luminosity
  functions and cosmic average line ratios
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 471
year: '2017'
...
