# The epoch of reionization in the R h = ct universe

http://hdl.handle.net/10150/615094
Title:
The epoch of reionization in the R h = ct universe
Author:
Melia, Fulvio; Fatuzzo, Marco
Affiliation:
The University of Arizona
Issue Date:
2016-01-11
Publisher:
OXFORD UNIV PRESS
Citation:
The epoch of reionization in the R h =  ct universe 2016, 456 (4):3422 Monthly Notices of the Royal Astronomical Society
Journal:
Monthly Notices of the Royal Astronomical Society
Rights:
Collection Information:
Abstract:
The measured properties of the epoch of reionization (EoR) show that reionization probably began around $z\sim 12-15$ and ended by $z=6$. In addition, a careful analysis of the fluctuations in the cosmic microwave background indicate a scattering optical depth $\tau\sim 0.066\pm0.012$ through the EoR. In the context of $\Lambda$CDM, 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 $f_{ion}\sim 0.2$, which is in tension with other observations that suggest a value as small as $\sim 0.05$. In this paper, we examine how reionization might have progressed in the alternative Friedmann-Robertson Walker cosmology known as the $R_{\rm h}=ct$ Universe, and determine the value of $f_{ion}$ required with this different rate of expansion. We find that $R_{\rm h}=ct$ accounts quite well for the currently known properties of the EoR, as long as its fractional baryon density falls within the reasonable range $0.026\lesssim \Omega_b\lesssim 0.037$. This model can also fit the EoR data with $f_{ion}\sim 0.05$, but only if the Lyman continuum photon production is highly efficient and $\Omega_b \sim 0.037$. 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 $R_{\rm h}=ct$ when complete structure formation models become available.
ISSN:
0035-8711; 1365-2966
DOI:
10.1093/mnras/stv2902
Version:
Final accepted manuscript
http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stv2902

DC FieldValue Language
dc.contributor.authorMelia, Fulvioen
dc.contributor.authorFatuzzo, Marcoen
dc.date.accessioned2016-06-29T19:38:39Z-
dc.date.available2016-06-29T19:38:39Z-
dc.date.issued2016-01-11-
dc.identifier.citationThe epoch of reionization in the R h =  ct universe 2016, 456 (4):3422 Monthly Notices of the Royal Astronomical Societyen
dc.identifier.issn0035-8711-
dc.identifier.issn1365-2966-
dc.identifier.doi10.1093/mnras/stv2902-
dc.identifier.urihttp://hdl.handle.net/10150/615094-
dc.description.abstractThe measured properties of the epoch of reionization (EoR) show that reionization probably began around $z\sim 12-15$ and ended by $z=6$. In addition, a careful analysis of the fluctuations in the cosmic microwave background indicate a scattering optical depth $\tau\sim 0.066\pm0.012$ through the EoR. In the context of $\Lambda$CDM, 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 $f_{ion}\sim 0.2$, which is in tension with other observations that suggest a value as small as $\sim 0.05$. In this paper, we examine how reionization might have progressed in the alternative Friedmann-Robertson Walker cosmology known as the $R_{\rm h}=ct$ Universe, and determine the value of $f_{ion}$ required with this different rate of expansion. We find that $R_{\rm h}=ct$ accounts quite well for the currently known properties of the EoR, as long as its fractional baryon density falls within the reasonable range $0.026\lesssim \Omega_b\lesssim 0.037$. This model can also fit the EoR data with $f_{ion}\sim 0.05$, but only if the Lyman continuum photon production is highly efficient and $\Omega_b \sim 0.037$. 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 $R_{\rm h}=ct$ when complete structure formation models become available.en
dc.language.isoenen
dc.publisherOXFORD UNIV PRESSen
dc.relation.urlhttp://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stv2902en
dc.titleThe epoch of reionization in the R h = ct universeen
dc.typeArticleen
dc.contributor.departmentThe University of Arizonaen
dc.identifier.journalMonthly Notices of the Royal Astronomical Societyen
dc.eprint.versionFinal accepted manuscripten