تقرير
Expanding covariant cosmography of the local Universe: incorporating the snap and axial symmetry
| العنوان: | Expanding covariant cosmography of the local Universe: incorporating the snap and axial symmetry |
|---|---|
| المؤلفون: | Kalbouneh, Basheer, Santiago, Jessica, Marinoni, Christian, Maartens, Roy, Clarkson, Chris, Sarma, Maharshi |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics General Relativity and Quantum Cosmology |
| مصطلحات موضوعية: | Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology |
| الوصف: | Studies show that the model-independent, fully non-perturbative covariant cosmographic approach is suitable for analyzing the local Universe $(z\lesssim 0.1)$. However, accurately characterizing large and inhomogeneous mass distributions requires the fourth-order term in the redshift expansion of the covariant luminosity distance $d_L(z,\boldsymbol{n})$. We calculate the covariant snap parameter $\mathbb{S}$ and its spherical harmonic multipole moments using the matter expansion tensor and the evolution equations for lightray bundles. The fourth-order term adds 36 degrees of freedom, since the highest independent multipole of the snap is the 32-pole (dotriacontapole) $(\ell=5)$. Including this term helps to de-bias estimations of the covariant deceleration parameter. Given that observations suggest axially symmetric anisotropies in the Hubble diagram for $z \lesssim 0.1$ and theory shows that only a subset of multipoles contributes to the signal, we demonstrate that only 12 degrees of freedom are needed for a model-independent description of the local universe. We use an analytical axisymmetric model of the local Universe, with data that matches the Zwicky Transient Facility survey, in order to provide a numerical example of the amplitude of the snap multipoles and to forecast precision. Comment: 13 + 7 pages |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2408.04333 |
| رقم الأكسشن: | edsarx.2408.04333 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |