12 research outputs found
Probing massive neutrinos with the Minkowski functionals of large-scale structure
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
Minkowski functionals (MFs), and quantify the constraints on the summed
neutrino mass from the MFs, by using publicly available N-body
simulations. We find the MFs provide important complementary information, and
give tighter constraints on 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 from
the MFs with a smoothing scale of Mpc is or times better
than that from the power spectrum. When the MFs are combined with the power
spectrum, they can improve the constraint on 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 from the MFs can reach eV
with a volume of , while the combination of the MFs and
power spectrum can tighten this constraint to be eV, a
significance on detecting the minimum sum of the neutrino masses. For the `m'
field, we also find the and degeneracy is broken with the
MFs, leading to stronger constraints on all 6 cosmological parameters
considered in this work than the power spectrum.Comment: Accepted for publication in JCAP. Changes from the first version: add
figure 10, and minor text revisions. Matches accepted version. 33 pages, 10
figures, 2 table
Probing massive neutrinos with the Minkowski functionals of the galaxy distribution
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, . 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 . 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 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
, and 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
, we obtain a 1 constraint of 0.059 eV with the MFs alone for
a volume of only .Comment: 33 pages, 5 + 4 figures, 4 tables. To be submitted to JCAP. Comments
welcome. arXiv admin note: text overlap with arXiv:2204.0294
The effects of peculiar velocities on the morphological properties of large-scale structure
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 from the MFs with one smoothing
scale can be better by 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.Comment: 6 pages, 3 figures, accepted by PR
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Dynamical Hotness, Star Formation Quenching, and Growth of Supermassive Black Holes
A stellar system is dynamically hot when its kinetic energy is dominated by random motion represented by the velocity dispersion σ _hot . We use MaNGA data to obtain the inner and outer dispersion of a galaxy, σ _in and σ _out , to characterize its dynamical status and study its connection with star formation quenching and the growth of its supermassive black hole (SMBH). We divide galaxies into fully quenched (FQGs), partially quenched (PQGs), and fully star-forming (FSGs) populations, and identify quenched central cores (QCCs) in PQGs. The galaxy distribution in ( σ _in / σ _hot )–( σ _out / σ _hot ) diagram is L-shaped, consisting of a horizontal sequence ( σ _out / σ _hot ∼ 0) and a vertical sequence ( σ _in / σ _hot ∼ 1). FQGs and QCCs are located at the top of the vertical sequence, σ _out / σ _hot ∼ 1, and are thus dynamically hot over their entire bodies. PQGs reside along the vertical sequence, so they have hot centers but cold outskirts. FSGs are diverse and can be found in both sequences. Galaxy structural properties, star formation, and AGN activities make a transition along the horizontal sequence at σ _in / σ _hot ∼ 0.5, and along the vertical sequence at σ _out / σ _hot ∼ 0.5. The fractions of optical AGNs and barred galaxies increase rapidly in the first transition and decline rapidly in the second; radio galaxies are located at the top of the vertical sequence. Our results demonstrate that star formation quenching and SMBH growth are effective only in dynamically hot systems. A simple model along this line can reproduce the observed SMBH scaling relations. We discuss how secular processes and strong interactions can make a system dynamically hot, and lead to the SMBH growth and star formation quenching