TY - JOUR
T1 - The epoch of reionization in the Rh = ct universe
AU - Melia, Fulvio
AU - Fatuzzo, Marco
N1 - Funding Information:
We are very grateful for the thoughtful and helpful comments provided by the anonymous referee. FM is grateful to Amherst College for its support through a John Woodruff Simpson Lectureship, and to Purple Mountain Observatory in Nanjing, China, for its hospitality while part of this work was being carried out. This work was partially supported by grant 2012T1J0011 from The Chinese Academy of Sciences Visiting Professorships for Senior International Scientists, and grant GDJ20120491013 from the Chinese State Administration of Foreign Experts Affairs. MF is supported at Xavier University through the Hauck Foundation.
Funding Information:
We are very grateful for the thoughtful and helpful comments provided by the anonymous referee. FM is grateful to Amherst College for its support through a John WoodruffSimpson Lectureship, and to Purple Mountain Observatory in Nanjing, China, for its hospitality while part of this work was being carried out. This work was partially supported by grant 2012T1J0011 from The Chinese Academy of Sciences Visiting Professorships for Senior International Scientists, and grant GDJ20120491013 from the Chinese State Administration of Foreign Experts Affairs. MF is supported at Xavier University through the Hauck Foundation.
Publisher Copyright:
© 2018 The Author(s).
PY - 2016/1/9
Y1 - 2016/1/9
N2 - The measured properties of the epoch of reionization (EoR) show that reionization probably began around z ~ 12-15 and ended by z = 6. In addition, a careful analysis of the fluctuations in the cosmic microwave background indicate a scattering optical depth τ ~ 0.066 ± 0.012 through the EoR. In the context of Γ cold dark matter, galaxies at intermediate redshifts and dwarf galaxies at higher redshifts now appear to be the principal sources of UV ionizing radiation, but only for an inferred (ionizing) escape fraction fion ~ 0.2, which is in tension with other observations that suggest a value as small as ~0.05. In this paper, we examine how reionization might have progressed in the alternative Friedmann-RobertsonWalker cosmology known as the Rh = ct universe, and determine the value of fion required with this different rate of expansion. We find that Rh =ct accounts quite well for the currently known properties of the EoR, as long as its fractional baryon density falls within the reasonable range 0.026 ≲ Ωb ≲ 0.037. This model can also fit the EoR data with fion ~ 0.05, but only if the Lyman continuum photon production is highly efficient and Ωb ~ 0.037. These results are still preliminary, however, given their reliance on a particular form of the star formation rate density, which is still uncertain at very high redshifts. It will also be helpful to reconsider the EoR in Rh = ct when complete structure formation models become available.
AB - The measured properties of the epoch of reionization (EoR) show that reionization probably began around z ~ 12-15 and ended by z = 6. In addition, a careful analysis of the fluctuations in the cosmic microwave background indicate a scattering optical depth τ ~ 0.066 ± 0.012 through the EoR. In the context of Γ cold dark matter, galaxies at intermediate redshifts and dwarf galaxies at higher redshifts now appear to be the principal sources of UV ionizing radiation, but only for an inferred (ionizing) escape fraction fion ~ 0.2, which is in tension with other observations that suggest a value as small as ~0.05. In this paper, we examine how reionization might have progressed in the alternative Friedmann-RobertsonWalker cosmology known as the Rh = ct universe, and determine the value of fion required with this different rate of expansion. We find that Rh =ct accounts quite well for the currently known properties of the EoR, as long as its fractional baryon density falls within the reasonable range 0.026 ≲ Ωb ≲ 0.037. This model can also fit the EoR data with fion ~ 0.05, but only if the Lyman continuum photon production is highly efficient and Ωb ~ 0.037. These results are still preliminary, however, given their reliance on a particular form of the star formation rate density, which is still uncertain at very high redshifts. It will also be helpful to reconsider the EoR in Rh = ct when complete structure formation models become available.
KW - Cosmological parameters
KW - Cosmology: observations
KW - Cosmology: theory
KW - Early universe
KW - Galaxies: general
KW - Quasars: general
UR - http://www.scopus.com/inward/record.url?scp=84960523741&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84960523741&partnerID=8YFLogxK
U2 - 10.1093/mnras/stv2902
DO - 10.1093/mnras/stv2902
M3 - Article
AN - SCOPUS:84960523741
VL - 456
SP - 3422
EP - 3431
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -