164 research outputs found
Search for sterile neutrinos in holographic dark energy cosmology: Reconciling Planck observation with the local measurement of the Hubble constant
We search for sterile neutrinos in the holographic dark energy cosmology by
using the latest observational data. To perform the analysis, we employ the
current cosmological observations, including the cosmic microwave background
temperature power spectrum data from the Planck mission, the baryon acoustic
oscillation measurements, the type Ia supernova data, the redshift space
distortion measurements, the shear data of weak lensing observation, the Planck
lensing measurement, and the latest direct measurement of as well. We
show that, compared to the CDM cosmology, the holographic dark energy
cosmology with sterile neutrinos can relieve the tension between the Planck
observation and the direct measurement of much better. Once we include
the measurement in the global fit, we find that the hint of the existence
of sterile neutrinos in the holographic dark energy cosmology can be given.
Under the constraint of the all-data combination, we obtain and , indicating
that the detection of in the holographic dark energy
cosmology is at the level and the massless or very light sterile
neutrino is favored by the current observations.Comment: 10 pages, 4 figures; typos corrected, published in PR
Synergy between CSST galaxy survey and gravitational-wave observation: Inferring the Hubble constant from dark standard sirens
Gravitational waves (GWs) from compact binary coalescences encode the
absolute luminosity distances of GW sources. Once the redshifts of GW sources
are known, one can use the distance-redshift relation to constrain cosmological
parameters. One way to obtain the redshifts is to localize GW sources by GW
observations and then use galaxy catalogs to determine redshifts from a
statistical analysis of redshift information of the potential host galaxies,
commonly referred to as the dark siren method. The third-generation (3G) GW
detectors are planned to work in the 2030s and will observe numerous compact
binary coalescences. Using these GW events as dark sirens requires high-quality
galaxy catalogs from future sky survey projects. The China Space Station
Telescope (CSST) will be launched in 2024 and will observe billions of galaxies
within a 17500 deg survey area with redshift up to , providing
photometric and spectroscopic galaxy catalogs. In this work, we simulate the
CSST galaxy catalogs and the 5-year GW data from the 3G GW detectors and
combine them to infer the Hubble constant (). Our results show that the
measurement precision of could reach the sub-percent level, meeting the
standard of precision cosmology. We conclude that the synergy between CSST and
the 3G GW detectors is of great significance in measuring the Hubble constant.Comment: 13 pages, 5 figure
Cosmology with fast radio bursts in the era of SKA
We present a forecast of the cosmological parameter estimation using fast
radio bursts (FRBs) from the upcoming Square Kilometre Array (SKA), focusing on
the issues of dark energy, the Hubble constant, and baryon density. We simulate
and localized FRBs from a 10-year SKA observation, and find that:
(i) using FRB data alone can tightly constrain dark-energy equation of
state parameters better than CMB+BAO+SN, providing a single cosmological probe
to explore dark energy; (ii) combining the FRB data with gravitational wave
standard siren data from 10-year observation with the Einstein Telescope, the
Hubble constant can be constrained to a sub-percent level, serving as a
powerful low-redshift probe; (iii) using FRB data can constrain the
baryon density to a precision of . Our results
indicate that SKA-era FRBs will provide precise cosmological measurements to
shed light on both dark energy and the missing baryon problem, and help resolve
the Hubble tension.Comment: 16 pages, 6 figure
First statistical measurement of the Hubble constant using unlocalized fast radio bursts
Fast radio bursts (FRBs) can be used to measure the Hubble constant by
employing the Macquart relation. However, at present, only a small number of
FRB events are localized to their host galaxies with known redshifts. In this
paper, we develop a Bayesian method to statistically measure the Hubble
constant using unlocalized FRBs and galaxy catalog data, which makes it
possible to constrain cosmological parameters by using a large number of FRB
data without known redshift information. Using the six FRB events observed by
ASKAP combined with the big bang nucleosynthesis result, we obtain
km s Mpc in the simulation-based case
and km s Mpc in the observation-based
case ( highest-density interval), assuming different host galaxy
population parameters. We also estimate that in the next few years, using
thousands of FRBs could achieve a precision on the random error of the
Hubble constant.Comment: 9 pages, 3 figure
Fast radio burst energy function in the presence of variation
Fast radio bursts (FRBs) have been found in great numbers but the physical
mechanism of these sources is still a mystery. The redshift evolutions of the
FRB energy distribution function and the volumetric rate shed light on
revealing the origin of the FRBs. However, such estimations rely on the
dispersion measurement (DM)-redshift () relationship. A few of FRBs detected
recently show large excess DM beyond the expectation from the cosmological and
Milky Way contributions, which indicates large spread of DM from their host
galaxies. In this work, we adopt the lognormal distributed
model and estimate the energy function using the non-repeating FRBs selected
from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Catalog 1.
By comparing the lognormal distributed model to the constant
model, the FRB energy function results are consistent within
the measurement uncertainty. We also estimate the volumetric rate of the
non-repeating FRBs in three different redshift bins. The volumetric rate shows
that the trend is consistent with the stellar-mass density redshift evolution.
Since the lognormal distributed model increases the measurement
errors, the inference of FRBs tracking the stellar-mass density is nonetheless
undermined.Comment: 8 pages, 5 figure
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