{"title":"Dark energy constraints from Pantheon+ Ia supernovae data","authors":"Sergio Torres-Arzayus","doi":"10.1007/s10509-024-04282-x","DOIUrl":null,"url":null,"abstract":"<div><p>Measurements of the current expansion rate of the Universe, <span>\\(H_{0}\\)</span>, using standard candles, disagree with those derived from observations of the Cosmic Microwave Background (CMB). This discrepancy, known as the <i>Hubble tension</i>, is substantial and suggests the possibility of revisions to the standard cosmological model (Cosmological constant <span>\\(\\Lambda \\)</span> and cold dark matter – <span>\\(\\Lambda CDM\\)</span>). Dynamic dark energy (DE) models that introduce deviations in the expansion history relative to <span>\\(\\Lambda CDM\\)</span> could potentially explain this tension. We used Type Ia supernovae (SNe) data to test a dynamic DE model consisting of an equation of state that varies linearly with the cosmological scale factor <span>\\(a\\)</span>. To evaluate this model, we developed a new statistic (the <span>\\(T_{\\alpha }\\)</span> statistic) used in conjunction with an optimization code that minimizes its value to obtain model parameters. The <span>\\(T_{\\alpha }\\)</span> statistic reduces bias errors (in comparison to the <span>\\(\\chi ^{2}\\)</span> statistic) because it retains the sign of the residuals, which is meaningful in testing the dynamic DE model as the deviations in the expansion history introduced by this model act asymmetrically in redshift space. The DE model fits the SNe data reasonably well, but the available SNe data lacks the statistical power to discriminate between <span>\\(\\Lambda CDM\\)</span> and alternative models. To further assess the model using CMB data, we computed the distance to the last scattering surface and compared the results with that derived from the <i>Planck</i> observations. Although the simple dynamic DE model tested does not completely resolve the tension, it is not ruled out by the data and could still play a role alongside other physical effects.</p></div>","PeriodicalId":8644,"journal":{"name":"Astrophysics and Space Science","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysics and Space Science","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s10509-024-04282-x","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Measurements of the current expansion rate of the Universe, \(H_{0}\), using standard candles, disagree with those derived from observations of the Cosmic Microwave Background (CMB). This discrepancy, known as the Hubble tension, is substantial and suggests the possibility of revisions to the standard cosmological model (Cosmological constant \(\Lambda \) and cold dark matter – \(\Lambda CDM\)). Dynamic dark energy (DE) models that introduce deviations in the expansion history relative to \(\Lambda CDM\) could potentially explain this tension. We used Type Ia supernovae (SNe) data to test a dynamic DE model consisting of an equation of state that varies linearly with the cosmological scale factor \(a\). To evaluate this model, we developed a new statistic (the \(T_{\alpha }\) statistic) used in conjunction with an optimization code that minimizes its value to obtain model parameters. The \(T_{\alpha }\) statistic reduces bias errors (in comparison to the \(\chi ^{2}\) statistic) because it retains the sign of the residuals, which is meaningful in testing the dynamic DE model as the deviations in the expansion history introduced by this model act asymmetrically in redshift space. The DE model fits the SNe data reasonably well, but the available SNe data lacks the statistical power to discriminate between \(\Lambda CDM\) and alternative models. To further assess the model using CMB data, we computed the distance to the last scattering surface and compared the results with that derived from the Planck observations. Although the simple dynamic DE model tested does not completely resolve the tension, it is not ruled out by the data and could still play a role alongside other physical effects.
期刊介绍:
Astrophysics and Space Science publishes original contributions and invited reviews covering the entire range of astronomy, astrophysics, astrophysical cosmology, planetary and space science and the astrophysical aspects of astrobiology. This includes both observational and theoretical research, the techniques of astronomical instrumentation and data analysis and astronomical space instrumentation. We particularly welcome papers in the general fields of high-energy astrophysics, astrophysical and astrochemical studies of the interstellar medium including star formation, planetary astrophysics, the formation and evolution of galaxies and the evolution of large scale structure in the Universe. Papers in mathematical physics or in general relativity which do not establish clear astrophysical applications will no longer be considered.
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