Hints of noncold dark matter? Observational constraints on barotropic dark matter with a constant equation of state parameter
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arXiv
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866909668531503104 |
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| author | Yao, Yan-Hong Liu, Jian-Qi |
| author_facet | Yao, Yan-Hong Liu, Jian-Qi |
| contents | This study investigates the potential of a cosmological model termed $Λw$DM, in which a cosmological constant play the role of dark energy and dark matter is barotropic and has a constant equation of state parameter ($w_{\rm dm}$), to address the $S_8$ tension between early- and late- universe observations. By incorporating the latest cosmological datasets -- including Planck Cosmic Microwave Background (CMB), Baryon Acoustic Oscillation (BAO), Ia supernovae (SNe Ia), Redshift Space Distortions (RSD), and weak lensing (WL) -- we constrain the $Λw$DM compared to $Λ$CDM. Our analysis reveals a marginal preference for a non-zero $w_{\rm dm}=2.7^{+2.0}_{-1.9}\times10^{-7}$( at 95\% confidence level) when combining CMB, SDSS BAO, SNe Ia, RSD, and WL data, and a marginal preference for a non-zero $w_{\rm dm} = 2.29^{+1.9}_{-2.0} \times 10^{-7}$( at 95\% confidence level) when combining CMB, DESI Y1 BAO, SNe Ia, RSD, and WL data. In addition, we find that, compared to $Λ$CDM, $Λw$DM can alleviate the $S_8$ tension from $>3σ$ to $<1σ$. Furthermore, we find that, for CMB+SDSS+PP+RSD+WL datasets, the $Λw$DM model is close to being positively preferred over the $Λ$CDM model. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_00478 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Hints of noncold dark matter? Observational constraints on barotropic dark matter with a constant equation of state parameter Yao, Yan-Hong Liu, Jian-Qi Cosmology and Nongalactic Astrophysics This study investigates the potential of a cosmological model termed $Λw$DM, in which a cosmological constant play the role of dark energy and dark matter is barotropic and has a constant equation of state parameter ($w_{\rm dm}$), to address the $S_8$ tension between early- and late- universe observations. By incorporating the latest cosmological datasets -- including Planck Cosmic Microwave Background (CMB), Baryon Acoustic Oscillation (BAO), Ia supernovae (SNe Ia), Redshift Space Distortions (RSD), and weak lensing (WL) -- we constrain the $Λw$DM compared to $Λ$CDM. Our analysis reveals a marginal preference for a non-zero $w_{\rm dm}=2.7^{+2.0}_{-1.9}\times10^{-7}$( at 95\% confidence level) when combining CMB, SDSS BAO, SNe Ia, RSD, and WL data, and a marginal preference for a non-zero $w_{\rm dm} = 2.29^{+1.9}_{-2.0} \times 10^{-7}$( at 95\% confidence level) when combining CMB, DESI Y1 BAO, SNe Ia, RSD, and WL data. In addition, we find that, compared to $Λ$CDM, $Λw$DM can alleviate the $S_8$ tension from $>3σ$ to $<1σ$. Furthermore, we find that, for CMB+SDSS+PP+RSD+WL datasets, the $Λw$DM model is close to being positively preferred over the $Λ$CDM model. |
| title | Hints of noncold dark matter? Observational constraints on barotropic dark matter with a constant equation of state parameter |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2507.00478 |