scholarly journals The constraint of H0 from galaxy clusters and Hubble parameter data

2017 ◽  
Vol 26 (11) ◽  
pp. 1750129
Author(s):  
Hai Huang ◽  
Long Huang
Keyword(s):  
Hubble Parameter ◽  
High Redshift ◽  
Confidence Region ◽  
Angular Diameter ◽  
Observation Data ◽  
Luminosity Distance ◽  
Dynamical Equations ◽  
Angular Diameter Distance ◽  
Acceleration Rate ◽  
Distance Formula

Using comoving distance [Formula: see text] and angular diameter distance [Formula: see text], we recalculate parameters describing kinematical state of the universe, still combining the kinematical model of universe but not relying on dynamical equations for gravity. Comoving distance [Formula: see text] comes from Hubble data [Formula: see text] and is more reliable. Angular diameter distance [Formula: see text] comes from SZE (Sunyaev–Zel’dovich Effect) and X-ray data, and needs calibration. In low redshift case, we use expansion of relation between luminosity distance and redshift about redshift [Formula: see text]; in high redshift case, we take variable substitution [Formula: see text], and expand the relation between luminosity distance and redshift about variable [Formula: see text] in order to reduce computational errors. Finally, we get the more precise value of Hubble parameter [Formula: see text] km ⋅ s[Formula: see text], corresponding to [Formula: see text] uncertainty in [Formula: see text] confidence region, also deceleration factor [Formula: see text] and acceleration rate [Formula: see text], and their statistical values and probability graph. We compare the values of [Formula: see text], [Formula: see text] and [Formula: see text] with those obtained from other observation data and model.

scholarly journals CALIBRATION OF GRB LUMINOSITY RELATIONS WITH COSMOGRAPHY

2012 ◽  
Vol 21 (02) ◽  
pp. 1250016 ◽  
Author(s):  
HE GAO ◽  
NAN LIANG ◽  
ZONG-HONG ZHU
Keyword(s):  
Gamma Ray ◽  
Background Radiation ◽  
Interpolation Method ◽  
High Redshift ◽  
Confidence Region ◽  
Acoustic Oscillation ◽  
Current Data ◽  
Observation Data ◽  
Luminosity Distance ◽  
Microwave Background Radiation

For the use of gamma-ray bursts (GRBs) to probe cosmology in a cosmology-independent way, a new method has been proposed to obtain luminosity distances of GRBs by interpolating directly from the Hubble diagram of SNe Ia, and then calibrating GRB relations at high redshift. In this paper, following the basic assumption in the interpolation method that objects at the same redshift should have the same luminosity distance, we propose another approach to calibrate GRB luminosity relations with cosmographic fitting directly from SN Ia data. In cosmography, there is a well-known fitting formula which can reflect the Hubble relation between luminosity distance and redshift with cosmographic parameters which can be fitted from observation data. Using the Cosmographic fitting results from the Union set of SNe Ia, we calibrate five GRB relations using GRB sample at z ≤ 1.4 and deduce distance moduli of GRBs at 1.4 < z ≤ 6.6 by generalizing above calibrated relations at high redshift. Finally, we constrain the dark energy parameterization models of the Chevallier–Polarski–Linder (CPL) model, the Jassal–Bagla–Padmanabhan (JBP) model and the Alam model with GRB data at high redshift, as well as with the cosmic microwave background radiation (CMB) and the baryonic acoustic oscillation (BAO) observations, and we find the ΛCDM model is consistent with the current data in 1-σ confidence region.

scholarly journals The failure of testing for cosmic opacity via the distance-duality relation

2020 ◽  
Vol 497 (1) ◽  
pp. 378-388
Author(s):  
Václav Vavryčuk ◽  
Pavel Kroupa
Keyword(s):  
Cosmological Model ◽  
Convincing Evidence ◽  
Duality Relation ◽  
Angular Diameter ◽  
Luminosity Distance ◽  
Angular Diameter Distance ◽  
Frequency Independent ◽  
Unique Interpretation ◽  
The Universe

ABSTRACT The distance-duality relation (DDR) between the luminosity distance DL and the angular diameter distance DA is viewed as a powerful tool for testing for the opacity of the Universe, being independent of any cosmological model. It was applied by many authors, who mostly confirm its validity and report a negligible opacity of the Universe. Nevertheless, a thorough analysis reveals that applying the DDR in cosmic opacity tests is tricky. Its applicability is strongly limited because of a non-unique interpretation of the DL data in terms of cosmic opacity and a rather low accuracy and deficient extent of currently available DA data. Moreover, authors usually assume that cosmic opacity is frequency independent and parametrize it in their tests by a prescribed phenomenological function. In this way, they only prove that cosmic opacity does not follow their assumptions. As a consequence, no convincing evidence of transparency of the universe using the DDR has so far been presented.

scholarly journals On the possibility of baryon acoustic oscillation measurements at redshift z > 7.6 with the Roman space telescope

2020 ◽  
Vol 498 (4) ◽  
pp. 4955-4970
Author(s):  
Siddharth Satpathy ◽  
Zhaozhou An ◽  
Rupert A C Croft ◽  
Tiziana Di Matteo ◽  
Ananth Tenneti ◽  
...  
Keyword(s):  
Large Scale ◽  
High Redshift ◽  
High Sensitivity ◽  
Acoustic Oscillation ◽  
Detection Sensitivity ◽  
Angular Diameter ◽  
Acoustic Oscillations ◽  
Space Telescope ◽  
Angular Diameter Distance ◽  
High Redshift Universe

ABSTRACT The Nancy Grace Roman Space Telescope (RST), with its field of view and high sensitivity will make surveys of cosmological large-scale structure possible at high redshifts. We investigate the possibility of detecting baryon acoustic oscillations (BAO) at redshifts z &gt; 7.6 for use as a standard ruler. We use data from the hydrodynamic simulation bluetides in conjunction with the gigaparsec-scale Outer Rim simulation and a model for patchy reionization to create mock RST High Latitude Survey grism data for Lyman α emission line selected galaxies at redshifts z = 7.4 to z = 10, covering 2280 deg2. We measure the monopoles of galaxies in the mock catalogues and fit the BAO features. We find that for a line flux of $L = 7\times 10^{-17} \ {\rm erg\, s^{-1}\, cm}^{-2}$, the 5σ detection limit for the current design, the BAO feature is partially detectable (measured in three out of four survey quadrants analysed independently). The resulting root mean square error on the angular diameter distance to z = 7.7 is 7.9 ${{\ \rm per\ cent}}$. If we improve the detection sensitivity by a factor of two (i.e. $L = 3.5\times 10^{-17} \ {\rm erg\, s^{-1}\, cm}^{-2}$), the distance error reduces to $1.4{{\ \rm per\ cent}}$. We caution that many more factors are yet to be modelled, including dust obscuration, the damping wing due to the intergalactic medium, and low redshift interlopers. If these issues do not strongly affect the results, or different observational techniques (such as use of multiple lines) can mitigate them, RST, or similar instruments may be able to constrain the angular diameter distance to the high redshift universe.

scholarly journals Hubble trouble or Hubble bubble?

2018 ◽  
Vol 27 (09) ◽  
pp. 1850102 ◽  
Author(s):  
Antonio Enea Romano
Keyword(s):  
Large Scale ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Density Field ◽  
Density Contrast ◽  
Recent Analysis ◽  
Inversion Method ◽  
Linear Perturbation ◽  
Luminosity Distance ◽  
Angular Diameter Distance

The recent analysis of low-redshift supernovae (SN) has increased the apparent tension between the value of [Formula: see text] estimated from low and high redshift observations such as the cosmic microwave background (CMB) radiation. At the same time other observations have provided evidence of the existence of local radial inhomogeneities extending in different directions up to a redshift of about [Formula: see text]. About [Formula: see text] of the Cepheids used for SN calibration are directly affected because they are located along the directions of these inhomogeneities. We compute with different methods the effects of these inhomogeneities on the low-redshift luminosity and angular diameter distance using an exact solution of the Einstein’s equations, linear perturbation theory and a low-redshift expansion. We confirm that at low redshift the dominant effect is the nonrelativistic Doppler redshift correction, which is proportional to the volume averaged density contrast and to the comoving distance from the center. We derive a new simple formula relating directly the luminosity distance to the monopole of the density contrast, which does not involve any metric perturbation. We then use it to develop a new inversion method to reconstruct the monopole of the density field from the deviations of the redshift uncorrected observed luminosity distance respect to the [Formula: see text]CDM prediction based on cosmological parameters obtained from large scale observations. The inversion method confirms the existence of inhomogeneities whose effects were not previously taken into account because the [Formula: see text] [G. Lavaux and M. J. Hudson, Mon. Not. R. Astron. Soc. 416 (2011) 2840] density field maps used to obtain the peculiar velocity [J. Carrick et al., Mon. Not. R. Astron. Soc. 450 (2015) 317] for redshift correction were for [Formula: see text], which is not a sufficiently large scale to detect the presence of inhomogeneities extending up to [Formula: see text]. The inhomogeneity does not affect the high redshift luminosity distance because the volume averaged density contrast tends to zero asymptotically, making the value of [Formula: see text] obtained from CMB observations insensitive to any local structure. The inversion method can provide a unique tool to reconstruct the density field at high redshift where only SN data is available, and in particular to normalize correctly the density field respect to the average large scale density of the Universe.

scholarly journals Cosmology, cosmic dust, and stellar dimming

2016 ◽  
Vol 94 (6) ◽  
pp. 531-539
Author(s):  
Chuck. S. Matthias
Keyword(s):  
Hubble Parameter ◽  
Positive Curvature ◽  
Initial Conditions ◽  
Mean Free Path ◽  
Big Bang ◽  
Optical Signal ◽  
Cosmic Dust ◽  
Luminosity Distance ◽  
Data Set ◽  
Distance Formula

A cosmology model is derived, forming an expanding, curved, unbounded, and finite universe resembling a three-dimensional hypersphere with positive curvature. Growth, curvature, and the expansion rate are forced by the initial conditions accompanying the emergence of space and time from the “big bang” singularity. The model generates several variables (past and present stellar distance, luminosity distance, time of emission, photon path, recession velocity, radiation temperature, universe circumference, and Hubble parameter) that are sole functions of redshift, z (readily measured by spectroscopic or photometric means). The model also presents two concepts that replace the need for cosmic inflation and dark energy. Equations for luminosity distance, dL, and Hubble parameter, H, compare extremely well with 28 values of baryon acoustic oscillation measured data over the redshift range 0.07 < z < 2.3. A second data set, compiled by NASA, consists of 27 000 type 1a supernovae measurements of luminosity distance and redshift (0.001 < z < 10). Although the data are extremely scattered, within the scatter is a narrow, well-defined core whose distance, [Formula: see text], exceeds the model value, dL, as redshift increases. The larger distance, [Formula: see text], resulting from a weaker than expected optical signal, is commonly explained as due to an acceleration of universe expansion. Alternatively, if the photons are assumed to be partially quenched by cosmic dust, in proportion to the distance travelled, the weakened core signal can be described by a radiative transfer equation. The resulting equation for [Formula: see text], with an extinction coefficient of 0.000 345 Mpc−1 (or a photon mean free path of 2900 Mpc), fits the core data perfectly.

scholarly journals Towards a self-consistent analysis of the anisotropic galaxy two- and three-point correlation functions on large scales: application to mock galaxy catalogues

2020 ◽  
Author(s):  
Naonori S Sugiyama ◽  
Shun Saito ◽  
Florian Beutler ◽  
Hee-Jong Seo
Keyword(s):  
Correlation Functions ◽  
Hubble Parameter ◽  
Theoretical Models ◽  
Practical Method ◽  
Acoustic Oscillation ◽  
Nonlinear Damping ◽  
Joint Analysis ◽  
Angular Diameter Distance ◽  
Point Correlation ◽  
Parameter Constraints

Abstract We establish a practical method for the joint analysis of anisotropic galaxy two- and three-point correlation functions (2PCF and 3PCF) on the basis of the decomposition formalism of the 3PCF using tri-polar spherical harmonics. We perform such an analysis with MultiDark Patchy mock catalogues to demonstrate and understand the benefit of the anisotropic 3PCF. We focus on scales above 80 h−1 Mpc, and use information from the shape and the baryon acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density field reconstruction to increase the signal-noise ratio of BAO in the 2PCF measurement, but not in the 3PCF measurement. In particular, we study in detail the constraints on the angular diameter distance and the Hubble parameter. We build a model of the bispectrum or 3PCF that includes the nonlinear damping of the BAO signal in redshift space. We carefully account for various uncertainties in our analysis including theoretical models of the 3PCF, window function corrections, biases in estimated parameters from the fiducial values, the number of mock realizations to estimate the covariance matrix, and bin size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole components shows a $30\%$ and $20\%$ improvement in Hubble parameter constraints before and after reconstruction of the 2PCF measurements, respectively, compared to the 2PCF analysis alone. This study clearly shows that the anisotropic 3PCF increases cosmological information from galaxy surveys and encourages further development of the modeling of the 3PCF on smaller scales than we consider.

scholarly journals THE MEGAMASER COSMOLOGY PROJECT. II. THE ANGULAR-DIAMETER DISTANCE TO UGC 3789

2010 ◽  
Vol 718 (2) ◽  
pp. 657-665 ◽  
Author(s):  
J. A. Braatz ◽  
M. J. Reid ◽  
E. M. L. Humphreys ◽  
C. Henkel ◽  
J. J. Condon ◽  
...  
Keyword(s):  
Angular Diameter ◽  
Angular Diameter Distance

scholarly journals Dark Energy Survey Year 1 results: measurement of the baryon acoustic oscillation scale in the distribution of galaxies to redshift 1

2018 ◽  
Vol 483 (4) ◽  
pp. 4866-4883 ◽  
Author(s):  
T M C Abbott ◽  
F B Abdalla ◽  
A Alarcon ◽  
S Allam ◽  
F Andrade-Oliveira ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cold Dark Matter ◽  
Angular Diameter ◽  
Acoustic Oscillations ◽  
Distance Measurements ◽  
Angular Diameter Distance ◽  
Dark Energy Survey ◽  
Trade Offs ◽  
Physical Scale ◽  
Energy Survey

ABSTRACT We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in the distribution of galaxies selected from the first year of Dark Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1336 deg2 with 0.6 < $z$photo < 1 and a typical redshift uncertainty of 0.03(1 + $z$). This sample was selected, as fully described in a companion paper, using a colour/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the comoving transverse separation, and spherical harmonics. Further, we compare results obtained from template-based and machine-learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, DA, at the effective redshift of our sample divided by the true physical scale of the BAO feature, rd. We obtain close to a 4 per cent distance measurement of DA($z$eff = 0.81)/rd = 10.75 ± 0.43. These results are consistent with the flat Λ cold dark matter concordance cosmological model supported by numerous other recent experimental results.

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