**Cosmological** Filaments in the light of Excursion Set of Saddle Points

**cosmological**

**models**and to address the missing baryon problem. The aim of this work is to introduce an analytical framework to study the statistics of filaments such as number density of them and also to obtain the length-mass relation. For this objective, we

**model**filaments as collapsed objects which have an extension in one direction, accordingly we use the ellipsoidal collapse to study the evolution of an over-dense region via gravitational instability. %In this context, we consider the critical density of filament formation, which will be a crucial parameter for number density count. We find that the nonlinear density of filaments in the epoch of formation is almost mass independent and is in order of $\sim 30$. By introducing {\it{filament's extended condition}} we find a fitting function for length-mass relation. For the statistics of filaments, we propose a novel framework named excursion set of saddle points. In this approach, we count the saddle points of the density field Hessian matrix, and relate it to the count of filaments. In addition, we addressed the filament in filament problem with up-crossing approximation.

4/10 relevant

arXiv

Dark Quest. I. Fast and Accurate Emulation of Halo Clustering Statistics and Its Application to Galaxy Clustering

**cosmological**

**models**sampled based on a maximin-distance Sliced Latin Hypercube Design. By using the halo catalogs extracted at multiple redshifts in the range of $z=[0,1.48]$, we develop Dark Emulator, which enables fast and accurate computations of the halo mass function, halo-matter cross-correlation, and halo auto-correlation as a function of halo masses, redshift, separations and

**cosmological**models, based on the Principal Component Analysis and the Gaussian Process Regression for the large-dimensional input and output data vector. We assess the performance of the emulator using a validation set of $N$-body simulations that are not used in training the emulator. We show that, for typical halos hosting CMASS galaxies in the Sloan Digital Sky Survey, the emulator predicts the halo-matter cross correlation, relevant for galaxy-galaxy weak lensing, with an accuracy better than $2\%$ and the halo auto-correlation, relevant for galaxy clustering correlation, with an accuracy better than $4\%$. We give several demonstrations of the emulator. It can be used to study properties of halo mass density profiles such as the mass-concentration relation and splashback radius for different cosmologies. The emulator outputs can be combined with an analytical prescription of halo-galaxy connection such as the halo occupation distribution at the equation level, instead of using the mock catalogs, to make accurate predictions of galaxy clustering statistics such as the galaxy-galaxy weak lensing and the projected correlation function for any

**model**within the $w$CDM cosmologies, in a few CPU seconds.

5/10 relevant

arXiv

The energy of the universe in the Bianchi type-II **cosmological** **model**

**cosmological**

**model**, I used the energy-momentum complexes of Einstein and M{\o}ller and obtained the zero total energy in these two prescriptions. Expand abstract.

**cosmological**model, I used the energy-momentum complexes of Einstein and M{\o}ller and obtained the zero total energy in these two prescriptions. This result reinforces the viewpoint of Albrow and Tryon that the universe must have a zero net value for all conserved quantities and be equivalent to the previous works of Nester et al. and Aydogdu et al.

7/10 relevant

arXiv

Dark Energy Survey Year 1 Results: Joint Analysis of Galaxy Clustering, Galaxy Lensing, and CMB Lensing Two-point Functions

**cosmological**constraints from the joint analysis of the two-point correlation functions between galaxy density and galaxy shear with CMB lensing. We test for consistency between these measurements and the DES-only two-point function measurements, finding no evidence for inconsistency in the context of flat $\Lambda$CDM

**cosmological**

**models**. Performing a joint analysis of five of the possible correlation functions between these fields (excluding only the CMB lensing autospectrum) yields $S_{8}\equiv \sigma_8\sqrt{\Omega_{\rm m}/0.3} = 0.782^{+0.019}_{-0.025}$ and $\Omega_{\rm m}=0.260^{+0.029}_{-0.019}$. We test for consistency between these five correlation function measurements and the Planck-only measurement of the CMB lensing autospectrum, again finding no evidence for inconsistency in the context of flat $\Lambda$CDM

**models**. Combining constraints from all six two-point functions yields $S_{8}=0.776^{+0.014}_{-0.021}$ and $\Omega_{\rm m}= 0.271^{+0.022}_{-0.016}$. These results provide a powerful test and confirmation of the results from the first year DES joint-probes analysis.

4/10 relevant

arXiv

Dark Energy Survey Year 1 Results: Constraints on Extended **Cosmological**
**Models** from Galaxy Clustering and Weak Lensing

**cosmological**

**models**dominated by dark matter and dark energy, $\Lambda$CDM and $w$CDM, by using a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Energy Survey (DES Y1) in combination with external data. We consider four extensions of the minimal dark energy-dominated scenarios: 1) nonzero curvature $\Omega_k$, 2) number of relativistic species $N_{\rm eff}$ different from the standard value of 3.046, 3) time-varying equation-of-state of dark energy described by the parameters $w_0$ and $w_a$ (alternatively quoted by the values at the pivot redshift, $w_p$, and $w_a$), and 4) modified gravity described by the parameters $\mu_0$ and $\Sigma_0$ that modify the metric potentials. We also consider external information from Planck CMB measurements; BAO measurements from SDSS, 6dF, and BOSS; RSD measurements from BOSS; and SNIa information from the Pantheon compilation. Constraints on curvature and the number of relativistic species are dominated by the external data; when these are combined with DES Y1, we find $\Omega_k=0.0020^{+0.0037}_{-0.0032}$ at the 68% confidence level, and $N_{\rm eff}

10/10 relevant

arXiv

Automated Lensing Learner: Automated Strong Lensing Identification with a Computer Vision Technique

**Models**trained on fewer images perform better in absence of the lens galaxy light. Expand abstract.

**model**on the HOG of mock strong galaxy-galaxy lens images similar to observations from the Hubble Space Telescope (HST) and LSST. We assess

**model**performance with the area under the curve (AUC) of a Receiver Operating Characteristic (ROC) curve.

**Models**trained on 10,000 lens and non-lens containing images images exhibit an AUC of 0.975 for an HST-like sample, 0.625 for one exposure of LSST, and 0.809 for 10-year mock LSST observations. Performance appears to continually improve with the training set size.

**Models**trained on fewer images perform better in absence of the lens galaxy light. However, with larger training data sets, information from the lens galaxy actually improves

**model**performance, indicating that HOG captures much of the morphological complexity of the arc finding problem. We test our classifier on data from the Sloan Lens ACS Survey and find that small scale image features reduces the efficiency of our trained

**model**. However, these preliminary tests indicate that some parameterizations of HOG can compensate for differences between observed mock data. One example best-case parameterization results in an AUC of 0.6 in the F814 filter image with other parameterization results equivalent to random performance.

4/10 relevant

arXiv

Redshift remapping and cosmic acceleration in dark-matter-dominated
**cosmological** **models**

**models**and constraints on

**cosmological**parameters from a joint analysis of all primary

**cosmologic**al probes including the local measurement of the Hubble constant, Type Ia supernovae, baryonic acoustic oscillations... Expand abstract.

**cosmological**redshift and cosmic scale factor underlies

**cosmological**inference from virtually all kinds of

**cosmological**observations, leading to the emergence of the LambdaCDM

**cosmological**

**model**. This relation is not a fundamental theory and thus observational determination of this function (redshift remapping) should be regarded as an insightful alternative to holding its standard form in analyses of

**cosmological**data. Here we present non-parametric reconstructions of redshift remapping in dark-matter-dominated

**models**and constraints on

**cosmological**parameters from a joint analysis of all primary

**cosmological**probes including the local measurement of the Hubble constant, Type Ia supernovae, baryonic acoustic oscillations (BAO), Planck observations of the cosmic microwave background (CMB) radiation (temperature power spectrum) and cosmic chronometers. The reconstructed redshift remapping points to an additional boost of redshift operating in late epoch of cosmic evolution, but affecting both low-redshift observations and the CMB. The

**model**predicts a significant difference between the actual Hubble constant, h=0.48+/-0.02, and its local determination, h_obs=0.73+/-0.02. The ratio of these two values coincides closely with the maximum expansion rate inside voids formed in the corresponding open

**cosmological**

**model**with Omega_m=0.87+/-0.03, whereas the actual value of the Hubble constant implies the age of the Universe that is compatible with the Planck LambdaCDM cosmology. The new dark-matter-dominated

**model**with redshift remapping provides excellent fits to all data and eliminates recently reported tensions between the Planck LambdaCDM cosmology, the local determination of the Hubble constant and the BAO measurements from the Ly-alpha forest of high-redshift quasars.

10/10 relevant

arXiv

Constraints on non-flat cosmologies with massive neutrinos after Planck 2015

**cosmological**

**models**(i.e., the $\Lambda$CDM and $\phi$CDM models) with massive neutrinos assuming two different neutrino mass hierarchies in both the spatially flat and non-flat scenarios, where in the $\phi$CDM

**model**the scalar field possesses an inverse power-law potential, $V(\phi)\propto {\phi}^{-\alpha}$ ($\alphaandgt;0$). Cosmic microwave background data from Planck 2015, baryon acoustic oscillations data from 6dFGS, SDSS-MGS, BOSS-LOWZ and BOSS CMASS-DR11, the JLA compilation of Type Ia supernova apparent magnitude observations, and the Hubble Space Telescope $H_0$ prior, are jointly employed to constrain the

**model**parameters. We first determine constraints assuming three species of degenerate massive neutrinos. In the spatially flat (non-flat) $\Lambda$CDM model, the sum of neutrino masses is bounded as $\Sigma m_{\nu} andlt; 0.165 (0.299)$ eV at 95% confidence level (CL). Correspondingly, in the flat (non-flat) $\phi$CDM model, we find $\Sigma m_{\nu} andlt; 0.164 (0.301)$ eV at 95% CL. The inclusion of spatial curvature as a free parameter results in a significant broadening of confidence regions for $\Sigma m_{\nu}$ and other parameters. In the scenario where the total neutrino mass is dominated by the heaviest neutrino mass eigenstate, we can obtain the similar conclusions as those obtained in the degenerate neutrino mass scenario. In addition, the results show that the bounds on $\Sigma m_{\nu}$ based on two different neutrino mass hierarchies have insignificant differences in the spatially flat case for both the $\Lambda$CDM and $\phi$CDM models, however, the corresponding differences are larger in the non-flat case.

4/10 relevant

arXiv

Quasi-isotropic expansion for a two-fluid **cosmological** **model** containing
radiation and string gas

**cosmological**

**model**, including radiation and string gas is constructed. Expand abstract.

**cosmological**model, including radiation and string gas is constructed. The first non-trivial order expressions for the metric coefficients, energy densities and velocities are explicitly written down. Their small and large time asymptotics are studied. It is found that the large time asymptotic for the anisotropic component of the metric coefficients grows faster than that of the isotropic (trace-proportional) component.

8/10 relevant

arXiv

Application of the Abel Equation of the 1st kind to an inflation
analysis of non-exactly solvable **cosmological** **models**

8/10 relevant

arXiv