---
_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'
...