507 research outputs found
DESI Legacy Imaging Surveys Data Release 9: Cosmological Constraints from Galaxy Clustering and Weak Lensing using the Minimal Bias Model
We present a tentative constraint on cosmological parameters and
from a joint analysis of galaxy clustering and galaxy-galaxy lensing
from DESI Legacy Imaging Surveys Data Release 9 (DR9), covering approximately
10000 square degrees and spanning the redshift range of 0.1 to 0.9. To study
the dependence of cosmological parameters on lens redshift, we divide lens
galaxies into seven approximately volume-limited samples, each with an equal
width in photometric redshift. To retrieve the intrinsic projected correlation
function from the lens samples, we employ a novel method
to account for redshift uncertainties. Additionally, we measured the
galaxy-galaxy lensing signal for each lens sample,
using source galaxies selected from the shear catalog by applying our
\texttt{Fourier\_Quad} pipeline to DR9 images. We model these observables
within the flat CDM framework, employing the minimal bias model. To
ensure the reliability of the minimal bias model, we apply conservative scale
cuts: and , for and
, respectively. Our findings suggest a mild tendency
that increases with lens redshift,
although this trend is only marginally significant. When we combine low
redshift samples, the value of is determined to be ,
consistent with the Planck results but significantly higher than the 3
2pt analysis by 2-5. Despite the fact that further refinements in
measurements and modeling could improve the accuracy of our results, the
consistency with standard values demonstrates the potential of our method for
more precise and accurate cosmology in the future.Comment: slightly different with the published versio
Halo Properties and Mass Functions of Groups/Clusters from the DESI Legacy Imaging Surveys DR9
Based on a large group/cluster catalog recently constructed from the DESI
Legacy Imaging Surveys DR9 using an extended halo-based group finder, we
measure and model the group-galaxy weak lensing signals for groups/clusters in
a few redshift bins within redshift range . Here, the
background shear signals are obtained based on the DECaLS survey shape catalog
derived with the \textsc{Fourier\_Quad} method. We divide the lens samples into
5 equispaced redshift bins and 7 mass bins, which allow us to probe the
redshift and mass dependence of the lensing signals and hence the resulting
halo properties. In addition to these sample selections, we have also checked
the signals around different group centers, e.g., brightest central galaxy
(BCG), luminosity weighted center and number weighted center. We use a lensing
model that includes off-centering to describe the lensing signals we measure
for all mass and redshift bins. The results demonstrate that our model
predictions for the halo masses, bias and concentrations are stable and
self-consistent among different samples for different group centers. Taking
advantage of the very large and complete sample of groups/clusters, as well as
the reliable estimation of their halo masses, we provide measurements of the
cumulative halo mass functions up to redshift , with a mass precision at
dex.Comment: revised version submitted to Ap
Groups and protocluster candidates in the CLAUDS and HSC-SSP joint deep surveys
ArtÃculo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMUsing the extended halo-based group finder developed by Yang et al., which is able to deal with galaxies via spectroscopic and photometric redshifts simultaneously, we construct galaxy group and candidate protocluster catalogs in a wide redshift range (0 2.0. By checking the galaxy number distributions within a 5-7 h -1Mpc projected separation and a redshift difference Δz ≤ 0.1 around those richest groups at redshift z > 2, we identify lists of 761, 343, and 43 protocluster candidates in the redshift bins 2 ≤ z < 3, 3 ≤ z < 4, and z ≥ 4, respectively. In general, these catalogs of galaxy groups and protocluster candidates will provide useful environmental information in probing galaxy evolution along cosmic tim
Succession in soil and vegetation caused by coastal embankment in southern Laizhou Bay, China—Flourish or degradation?
Towards a muon collider
A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work
Towards a Muon Collider
A muon collider would enable the big jump ahead in energy reach that is
needed for a fruitful exploration of fundamental interactions. The challenges
of producing muon collisions at high luminosity and 10 TeV centre of mass
energy are being investigated by the recently-formed International Muon
Collider Collaboration. This Review summarises the status and the recent
advances on muon colliders design, physics and detector studies. The aim is to
provide a global perspective of the field and to outline directions for future
work.Comment: 118 pages, 103 figure
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