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| Natura: | Preprint |
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2025
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| Accesso online: | https://arxiv.org/abs/2512.10802 |
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| _version_ | 1866918244487528448 |
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| author | Sakr, Ziad Quartin, Miguel |
| author_facet | Sakr, Ziad Quartin, Miguel |
| contents | In this work we propose a phenomenological modification to the continuity equation at the linear perturbation level and test it using combinations of the CMB temperature, polarization and lensing potential angular spectrum, the ISW-galaxy cross power spectrum and the 3$\times$2pt lensing and galaxy clustering from DES survey. We investigate two parametrisations of this modification, both proportional to a new parameter $A_c$, which is assumed to be either constant in time, or proportional to the scale factor $a$, in order to be more relevant at late times. We find DES and ISW data to be consistent with the standard continuity equation when $A_c$ is constant, but 2--3$σ$ hints of a non-zero modification appear when Planck data is included. The model $A_c \propto a$ results in stronger tensions. We also test the effects of including the common extra parameters $μ$ and $η$ that modify the Poisson equation and Weyl potential. Although $A_c$, $μ$ and $η$ are correlated, we still find non-zero $A_c$ when Planck data is included or without Planck if $A_c \propto a$ and only either $η$ or $μ$ are allowed to vary. We conclude that violations of the continuity equation should be considered with care when testing additional deviations from general relativity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_10802 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | On the validity of the continuity equation in a modified gravity framework with CMB, DES 3x2pt and tomographic ISW data Sakr, Ziad Quartin, Miguel Cosmology and Nongalactic Astrophysics In this work we propose a phenomenological modification to the continuity equation at the linear perturbation level and test it using combinations of the CMB temperature, polarization and lensing potential angular spectrum, the ISW-galaxy cross power spectrum and the 3$\times$2pt lensing and galaxy clustering from DES survey. We investigate two parametrisations of this modification, both proportional to a new parameter $A_c$, which is assumed to be either constant in time, or proportional to the scale factor $a$, in order to be more relevant at late times. We find DES and ISW data to be consistent with the standard continuity equation when $A_c$ is constant, but 2--3$σ$ hints of a non-zero modification appear when Planck data is included. The model $A_c \propto a$ results in stronger tensions. We also test the effects of including the common extra parameters $μ$ and $η$ that modify the Poisson equation and Weyl potential. Although $A_c$, $μ$ and $η$ are correlated, we still find non-zero $A_c$ when Planck data is included or without Planck if $A_c \propto a$ and only either $η$ or $μ$ are allowed to vary. We conclude that violations of the continuity equation should be considered with care when testing additional deviations from general relativity. |
| title | On the validity of the continuity equation in a modified gravity framework with CMB, DES 3x2pt and tomographic ISW data |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2512.10802 |