### Abstract

We use 32 age measurements of passively evolving galaxies as a function of redshift to test and compare the standard model (λCDM) with the R<inf>h</inf> = ct universe. We show that the latter fits the data with a reduced χ<inf>dof</inf><sup>2</sup> = 0.435 for a Hubble constant = H<inf>0</inf> 67.2<inf>-4.0</inf> <sup>+4.5</sup> km s<sup>-1</sup> Mpc<sup>-1</sup>. By comparison, the optimal flat λCDM model, with two free parameters (including ω<inf>m</inf> = 0.12<inf>-0.11</inf><sup>+0.54</sup> and = - H 94.3+ 0 35.8 32.7 km s?1 Mpc-1), fits the age-z data with a reduced c = 0.428 dof 2 . Based solely on their cdof 2 values, both models appear to account for the data very well, though the optimized ?CDM parameters are only marginally consistent with those of the concordance model (Wm = 0.27 and H0 = 70 km s-1 Mpc-1). Fitting the age-z data with the latter results in a reduced χ<inf>dof</inf><sup>2</sup> = 0.523. However, because of the different number of free parameters in these models, selection tools, such as the Akaike, Kullback and Bayes Information Criteria, favor R<inf>h</inf> = ct over ?CDM with a likelihood of ?66.5%80.5% versus ∼19.5%33.5%. These results are suggestive, though not yet compelling, given the current limited galaxy age-z sample. We carry out Monte Carlo simulations based on these current age measurements to estimate how large the sample would have to be in order to rule out either model at a ∼99.7% confidence level. We find that if the real cosmology is λCDM, a sample of ?45 galaxy ages would be sufficient to rule out Rh = ct at this level of accuracy, while ?350 galaxy ages would be required to rule out λCDM if the real universe were instead Rh = ct. This difference in required sample size reflects the greater number of free parameters available to fit the data with λCDM.

Original language | English (US) |
---|---|

Article number | 35 |

Journal | Astronomical Journal |

Volume | 150 |

Issue number | 1 |

DOIs | |

State | Published - Jul 1 2015 |

### Fingerprint

### Keywords

- cosmology: observations
- cosmology: theory
- early universe
- Galaxy: general

### ASJC Scopus subject areas

- Space and Planetary Science
- Astronomy and Astrophysics

### Cite this

*Astronomical Journal*,

*150*(1), [35]. https://doi.org/10.1088/0004-6256/150/1/35

**THE AGE-REDSHIFT RELATIONSHIP OF OLD PASSIVE GALAXIES.** / Wei, Jun Jie; Wu, Xue Feng; Melia, Fulvio; Wang, Fa Yin; Yu, Hai.

Research output: Contribution to journal › Article

*Astronomical Journal*, vol. 150, no. 1, 35. https://doi.org/10.1088/0004-6256/150/1/35

}

TY - JOUR

T1 - THE AGE-REDSHIFT RELATIONSHIP OF OLD PASSIVE GALAXIES

AU - Wei, Jun Jie

AU - Wu, Xue Feng

AU - Melia, Fulvio

AU - Wang, Fa Yin

AU - Yu, Hai

PY - 2015/7/1

Y1 - 2015/7/1

N2 - We use 32 age measurements of passively evolving galaxies as a function of redshift to test and compare the standard model (λCDM) with the Rh = ct universe. We show that the latter fits the data with a reduced χdof2 = 0.435 for a Hubble constant = H0 67.2-4.0 +4.5 km s-1 Mpc-1. By comparison, the optimal flat λCDM model, with two free parameters (including ωm = 0.12-0.11+0.54 and = - H 94.3+ 0 35.8 32.7 km s?1 Mpc-1), fits the age-z data with a reduced c = 0.428 dof 2 . Based solely on their cdof 2 values, both models appear to account for the data very well, though the optimized ?CDM parameters are only marginally consistent with those of the concordance model (Wm = 0.27 and H0 = 70 km s-1 Mpc-1). Fitting the age-z data with the latter results in a reduced χdof2 = 0.523. However, because of the different number of free parameters in these models, selection tools, such as the Akaike, Kullback and Bayes Information Criteria, favor Rh = ct over ?CDM with a likelihood of ?66.5%80.5% versus ∼19.5%33.5%. These results are suggestive, though not yet compelling, given the current limited galaxy age-z sample. We carry out Monte Carlo simulations based on these current age measurements to estimate how large the sample would have to be in order to rule out either model at a ∼99.7% confidence level. We find that if the real cosmology is λCDM, a sample of ?45 galaxy ages would be sufficient to rule out Rh = ct at this level of accuracy, while ?350 galaxy ages would be required to rule out λCDM if the real universe were instead Rh = ct. This difference in required sample size reflects the greater number of free parameters available to fit the data with λCDM.

AB - We use 32 age measurements of passively evolving galaxies as a function of redshift to test and compare the standard model (λCDM) with the Rh = ct universe. We show that the latter fits the data with a reduced χdof2 = 0.435 for a Hubble constant = H0 67.2-4.0 +4.5 km s-1 Mpc-1. By comparison, the optimal flat λCDM model, with two free parameters (including ωm = 0.12-0.11+0.54 and = - H 94.3+ 0 35.8 32.7 km s?1 Mpc-1), fits the age-z data with a reduced c = 0.428 dof 2 . Based solely on their cdof 2 values, both models appear to account for the data very well, though the optimized ?CDM parameters are only marginally consistent with those of the concordance model (Wm = 0.27 and H0 = 70 km s-1 Mpc-1). Fitting the age-z data with the latter results in a reduced χdof2 = 0.523. However, because of the different number of free parameters in these models, selection tools, such as the Akaike, Kullback and Bayes Information Criteria, favor Rh = ct over ?CDM with a likelihood of ?66.5%80.5% versus ∼19.5%33.5%. These results are suggestive, though not yet compelling, given the current limited galaxy age-z sample. We carry out Monte Carlo simulations based on these current age measurements to estimate how large the sample would have to be in order to rule out either model at a ∼99.7% confidence level. We find that if the real cosmology is λCDM, a sample of ?45 galaxy ages would be sufficient to rule out Rh = ct at this level of accuracy, while ?350 galaxy ages would be required to rule out λCDM if the real universe were instead Rh = ct. This difference in required sample size reflects the greater number of free parameters available to fit the data with λCDM.

KW - cosmology: observations

KW - cosmology: theory

KW - early universe

KW - Galaxy: general

UR - http://www.scopus.com/inward/record.url?scp=84936100197&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84936100197&partnerID=8YFLogxK

U2 - 10.1088/0004-6256/150/1/35

DO - 10.1088/0004-6256/150/1/35

M3 - Article

VL - 150

JO - Astronomical Journal

JF - Astronomical Journal

SN - 0004-6256

IS - 1

M1 - 35

ER -