---
OA_place: repository
OA_type: green
_id: '18728'
abstract:
- lang: eng
  text: We discuss currently available observational constraints on the reionization
    history of the intergalactic medium (IGM), and the extent to which accreting black
    holes (BHs) can help explain these observations. We show new evidence, based on
    the combined statistics of Lyman α and β absorption in quasar spectra, that the
    IGM contains a significant amount of neutral hydrogen, and is experiencing rapid
    ionization at redshift z~ 6. However, we argue that quasar BHs, even faint ones
    that are below the detection thresholds of existing optical surveys, are unlikely
    to drive the evolution of the neutral fraction around this epoch, because they
    would over–produce the present–day soft X–ray background. On the other hand, the
    seeds of the z~ 6 quasar BHs likely appeared at much earlier epochs (z~ 20), and
    produced hard ionizing radiation by accretion. These early BHs are promising candidates
    to account for the high redshift (z~ 15) ionization implied by the recent cosmic
    microwave anisotropy data from WMAP. Using a model for the growth of BHs by accretion
    and mergers in a hierarchical cosmology, we suggest that the early growth of quasars
    must include a super-Eddington growth phase, and that, although not yet optically
    identified, the FIRST radio survey may have already detected several thousand
    >108M⊙ BHs at z>6.
alternative_title:
- ESO Astrophysics Symposia
article_processing_charge: No
arxiv: 1
author:
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
  orcid: 0000-0003-3633-5403
- first_name: M.
  full_name: Dijkstra, M.
  last_name: Dijkstra
- first_name: A.
  full_name: Mesinger, A.
  last_name: Mesinger
citation:
  ama: 'Haiman Z, Dijkstra M, Mesinger A. The growth of the earliest supermassive
    black holes and their contribution to reionization. In: <i>Proceedings of the
    MPA/ESO/MPE/USM Joint Astronomy Conference</i>. Springer Nature; 2005:30-41. doi:<a
    href="https://doi.org/10.1007/11403913_3">10.1007/11403913_3</a>'
  apa: 'Haiman, Z., Dijkstra, M., &#38; Mesinger, A. (2005). The growth of the earliest
    supermassive black holes and their contribution to reionization. In <i>Proceedings
    of the MPA/ESO/MPE/USM Joint Astronomy Conference</i> (pp. 30–41). Garching, Germany:
    Springer Nature. <a href="https://doi.org/10.1007/11403913_3">https://doi.org/10.1007/11403913_3</a>'
  chicago: Haiman, Zoltán, M. Dijkstra, and A. Mesinger. “The Growth of the Earliest
    Supermassive Black Holes and Their Contribution to Reionization.” In <i>Proceedings
    of the MPA/ESO/MPE/USM Joint Astronomy Conference</i>, 30–41. Springer Nature,
    2005. <a href="https://doi.org/10.1007/11403913_3">https://doi.org/10.1007/11403913_3</a>.
  ieee: Z. Haiman, M. Dijkstra, and A. Mesinger, “The growth of the earliest supermassive
    black holes and their contribution to reionization,” in <i>Proceedings of the
    MPA/ESO/MPE/USM Joint Astronomy Conference</i>, Garching, Germany, 2005, pp. 30–41.
  ista: Haiman Z, Dijkstra M, Mesinger A. 2005. The growth of the earliest supermassive
    black holes and their contribution to reionization. Proceedings of the MPA/ESO/MPE/USM
    Joint Astronomy Conference. MPA/ESO/MPE/USM Joint Astronomy Conference, ESO Astrophysics
    Symposia, , 30–41.
  mla: Haiman, Zoltán, et al. “The Growth of the Earliest Supermassive Black Holes
    and Their Contribution to Reionization.” <i>Proceedings of the MPA/ESO/MPE/USM
    Joint Astronomy Conference</i>, Springer Nature, 2005, pp. 30–41, doi:<a href="https://doi.org/10.1007/11403913_3">10.1007/11403913_3</a>.
  short: Z. Haiman, M. Dijkstra, A. Mesinger, in:, Proceedings of the MPA/ESO/MPE/USM
    Joint Astronomy Conference, Springer Nature, 2005, pp. 30–41.
conference:
  end_date: 2004-06-25
  location: Garching, Germany
  name: MPA/ESO/MPE/USM Joint Astronomy Conference
  start_date: 2004-06-21
date_created: 2025-01-03T12:24:03Z
date_published: 2005-12-22T00:00:00Z
date_updated: 2025-01-07T11:33:38Z
day: '22'
doi: 10.1007/11403913_3
extern: '1'
external_id:
  arxiv:
  - astro-ph/0409099
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/astro-ph/0409099
month: '12'
oa: 1
oa_version: Preprint
page: 30-41
publication: Proceedings of the MPA/ESO/MPE/USM Joint Astronomy Conference
publication_identifier:
  eissn:
  - 1611-6143
  isbn:
  - '9783540252757'
  issn:
  - 1431-2433
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: The growth of the earliest supermassive black holes and their contribution
  to reionization
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2005'
...