分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： It is known that the large-scale structure (LSS) mapped by a galaxy redshift survey is subject to distortions by galaxies' peculiar velocities. Besides the signatures generated in common N-point statistics, such as the anisotropy in the galaxy 2-point correlation function, the peculiar velocities also induce distinct features in LSS's morphological properties, which are fully described by four Minkowski functionals (MFs), i.e., the volume, surface area, integrated mean curvature and Euler characteristic (or genus). In this work, by using large suite of N-body simulations, we present and analyze these important features in the MFs of LSS on both (quasi-)linear and non-linear scales, with a focus on the latter. We also find the MFs can give competitive constraints on cosmological parameters compared to the power spectrum, probablly due to the non-linear information contained. For galaxy number density similar to the DESI BGS galaxies, the constraint on $\sigma_8$ from the MFs with one smoothing scale can be better by $\sim 50\%$ than from the power spectrum. These findings are important for the cosmological applications of MFs of LSS, and probablly open up a new avenue for studying the peculiar velocity field itself.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Massive neutrinos suppress the growth of structure under their free-streaming scales. The effect is most prominent on small scales where the widely-used two-point statistics can no longer capture the full information. In this work, we study the signatures massive neutrinos leave on large-scale structure (LSS) as revealed by its morphological properties, which are fully described by $4$ Minkowski functionals (MFs), and quantify the constraints on the summed neutrino mass $M_{\nu}$ from the MFs, by using publicly available N-body simulations. We find the MFs provide important complementary information, and give tighter constraints on $M_{\nu}$ than the power spectrum. Specifically, depending on whether massive neutrinos are included in the density field (the `m' field) or not (the `cb' field), we find the constraint on $M_{\nu}$ from the MFs with a smoothing scale of $R_G=5 h^{-1}$Mpc is $48$ or $4$ times better than that from the power spectrum. When the MFs are combined with the power spectrum, they can improve the constraint on $M_{\nu}$ from the latter by a factor of 63 for the `m' field and 5 for the `cb' field. Notably, when the `m' field is used, the constraint on $M_{\nu}$ from the MFs can reach $0.0177$eV with a volume of $1(h^{-1}\rm Gpc)^3$, while the combination of the MFs and power spectrum can tighten this constraint to be $0.0133$eV, a $4.5\sigma$ significance on detecting the minimum sum of the neutrino masses. For the `m' field, we also find the $\sigma_8$ and $M_{\nu}$ degeneracy is broken with the MFs, leading to stronger constraints on all 6 cosmological parameters considered in this work than the power spectrum.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The characteristic signatures of massive neutrinos on large-scale structure (LSS), if fully captured, can be used to put a stringent constraint on their mass sum, $M_{\nu}$. Previous work utilizing N-body simulations has shown the Minkowski functionals (MFs) of LSS can reveal the imprints of massive neutrinos on LSS, provide important complementary information to two-point statistics and significantly improve constraints on $M_{\nu}$. In this work, we take a step forward and apply the statistics to the biased tracers of LSS, i.e. the galaxies, and in redshift space. We perform a Fisher matrix analysis and quantify the constraining power of the MFs by using the Molino mock galaxy catalogs, which are constructed based on the halo occupation distribution (HOD) framework with parameters for the SDSS $M_r < -21.5$ and -22 galaxy samples. We find the MFs give tighter constraints on all of the cosmological parameters that we consider than the power spectrum. The constraints on $\Omega_{\mathrm{m}}, \Omega_{\mathrm{b}}, h, n_s, \sigma_8$, and $M_\nu$ from the MFs are better by a factor of 1.9, 2.9, 3.7, 4.2, 2.5, and 5.7, respectively, after marginalizing over the HOD parameters. Specifically, for $M_{\nu}$, we obtain a 1$\sigma$ constraint of 0.059 eV with the MFs alone for a volume of only $\left(1 h^{-1} \mathrm{Gpc}\right)^3$.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The characteristic signatures of massive neutrinos on large-scale structure (LSS), if fully captured, can be used to put a stringent constraint on their mass sum, $M_{\nu}$. Previous work utilizing N-body simulations has shown the Minkowski functionals (MFs) of LSS can reveal the imprints of massive neutrinos on LSS, provide important complementary information to two-point statistics and significantly improve constraints on $M_{\nu}$. In this work, we take a step forward and apply the statistics to the biased tracers of LSS, i.e. the galaxies, and in redshift space. We perform a Fisher matrix analysis and quantify the constraining power of the MFs by using the Molino mock galaxy catalogs, which are constructed based on the halo occupation distribution (HOD) framework with parameters for the SDSS $M_r < -21.5$ and -22 galaxy samples. We find the MFs give tighter constraints on all of the cosmological parameters that we consider than the power spectrum. The constraints on $\Omega_{\mathrm{m}}, \Omega_{\mathrm{b}}, h, n_s, \sigma_8$, and $M_\nu$ from the MFs are better by a factor of 1.9, 2.9, 3.7, 4.2, 2.5, and 5.7, respectively, after marginalizing over the HOD parameters. Specifically, for $M_{\nu}$, we obtain a 1$\sigma$ constraint of 0.059 eV with the MFs alone for a volume of only $\left(1 h^{-1} \mathrm{Gpc}\right)^3$.
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