Aiming at comparing different morphological models of galaxy clusters, we use two new methods to make a cosmological model-independent test of the distance-duality (DD) relation. The luminosity distances come from Union2 compilation of Supernovae Type Ia. The angular diameter distances are given by two cluster models (De Filippis et al. and Bonamente et al.). The advantage of our methods is that it can reduce statistical errors. Concerning the morphological hypotheses for cluster models, it is mainly focused on the comparison between elliptical $β$-model and spherical $β$-model. The spherical $β$-model is divided into two groups in terms of different reduction methods of angular diameter distances, i.e. conservative spherical $β$-model and corrected spherical $β$-model. Our results show that the DD relation is consistent with the elliptical $β$-model at $1σ$ confidence level (CL) for both methods, whereas for almost all spherical $β$-model parameterizations, the DD relation can only be accommodated at $3σ$ CL, particularly for the conservative spherical $β$-model. In order to minimize systematic uncertainties, we also apply the test to the overlap sample, i.e. the same set of clusters modeled by both De Filippis et al. and Bonamente et al.. It is found that the DD relation is compatible with the elliptically modeled overlap sample at $1σ$ CL, however for most of the parameterizations, the DD relation can not be accommodated even at $3σ$ CL for any of the two spherical $β$-models. Therefore it is reasonable that the marked triaxial ellipsoidal model is a better geometrical hypothesis describing the structure of the galaxy cluster compared with the spherical $β$-model if the DD relation is valid in cosmological observations.
The distance-duality relation (DDR) between the luminosity distance $D_L$ and the angular diameter distance $D_A$ 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 $D_L$ data in terms of cosmic opacity and a rather low accuracy and def…
In this work, we propose a powerful probe of neutrino effects on the large-scale structure (LSS) of the Universe, i.e., Minkowski functionals (MFs). The morphology of LSS can be fully described by four MFs. This tool, with strong statistical power, is robust to various systematics and can comprehensively probe all orders of N-point statistics. By using a pair of high-resolution N-body simulations, for the first time, we comprehensively studied the subtle neutrino effects on the morphology of LSS. For an ideal LSS survey of volume $\sim1.73$ Gpc$^3$/$h^3$, neutrino signals are mainly detected f…
{In this paper, we use large scale structure observations to test the redshift dependence of cosmic distance duality relation (CDDR), $D_{\rm L}(1+z)^{-2}/D_{\rm A}=η(z)$}, with $D_{\rm L}$ and $D_{\rm A}$, being the luminosity and angular diameter distances, respectively. In order to perform the test, the following data set are considered: strong lensing systems and galaxy cluster measurements (gas mass fractions). No specific cosmological model is adopted, only a flat universe is assumed. { By considering two $η(z)$ parametrizations, It is observed that the CDDR remain redshift independent w…
The cosmic distance duality relation (CDDR), $D_{\rm L}(1+z)^{-2}/D_{\rm A}=η=1$, with $D_{\rm L}$ and $D_{\rm A}$, being the luminosity and angular diameter distances, respectively, is a crucial premise in cosmological scenarios. Many investigations try to test CDDR through observational approaches, even some of these ones also consider a deformed CDDR, i.e., $η=η(z)$. In this paper, we use type Ia supernovae luminosity distances and galaxy cluster measurements (their angular diameter distances and gas mass fractions) in order to perform a Bayesian model comparison between $ η(z) $ functions.…
We introduce a versatile and spatially resolved morphological characterisation of binary fields, rooted in the opening transform of mathematical morphology. We subsequently apply it to the thresholded ionization field in simulations of cosmic reionization and study the morphology of ionized regions. We find that an ionized volume element typically resides in an ionized region with radius $\sim8\,h^{-1}\mathrm{cMpc}$ at the midpoint of reionization ($z\approx7.5$) and follow the bubble size distribution even beyond the overlap phase. We find that percolation of the fully ionized component sets …
General relativity reproduces main current cosmological observations, assuming the validity of cosmic distance duality relation (CDDR) at all scales and epochs. However, CDDR is poorly tested in the redshift interval between the farthest observed Type Ia supernovae (SN Ia) and that of the Cosmic Microwave background (CMB). We present a new idea of testing the validity of CDDR, through the multiple measurements of high-redshift quasars. Luminosity distances are derived from the relation between the UV and X-ray luminosities of quasars, while angular diameter distances are obtained from the comp…
The cosmic distance duality relation (CDDR) is a fundamental assumption in cosmological studies. Given the redshift $z$, it relates luminosity distance $D^L$ with angular diameter distance $D^A$ through $(1+z)^2D^A/D^L\equiv1$. Many efforts have been devoted to test the CDDR with various observational approaches. However, to the best of our knowledge, those methods are always affected by cosmic opacity which could make the CDDR violated due to the non-conservation of photon number. Such mechanism is more related with astropartical physics. In this work, to directly study the nature of space-ti…
Crawling the Cosmic Network: Exploring the Morphology of Structure in the Galaxy Distribution
虽然相干的大尺度结构，如细丝和墙壁是显而易见的星系红移调查，他们迄今为止被证明难以用计算机算法来表征。本文提出了一种利用星系密度场Hessian矩阵的特征值和特征向量来表征大尺度结构形态的方法。通过分析平滑的密度场及其海森矩阵，我们可以确定结构的类型-壁，细丝或团块-作为尺度的函数主导星系的大尺度分布。我们已经运行的模拟星系分布的LCDM宇宙学N体模拟和斯隆数字巡天观测到的星系分布的算法。两个星表的结构形态相似，在10 - 20 h ^{-1} Mpc平滑尺度上均以顺磁为主，在5 h ^{-1} Mpc尺度上均以团块为主。在这两种分布中都有壁存在的证据，但在小于~25 h ^{-1} Mpc的尺度上，壁并不是主要的结构。模拟的分析表明，在一个给定的共动平滑尺度，结构随着时间的推移，从墙壁到细丝到团块，在较小的平滑尺度上发现的那些在给定的时间进一步在这个过程中。
We obtain the current constraint on the minimally extended varying speed of light (meVSL) model by analyzing cosmic distance duality relation (CCDDR) of it, $D_{L}/D_{A}(1+z)^{-2} = (1+z)^{b/8}$. We use the Pantheon type Ia supernova (SNIa) data, the Hubble parameter $H(z)$ using the cosmic chronometers approach, and the cosmic microwave background (CMB) distance priors from the latest Planck data. We find that the current data show the 1-$σ$ deviation from the standard CCDDR. Thus, this provides the constraint on meVSL model and future precision observations might be able to put stronger cons…
We carry out a test of the cosmic distance duality relation using a sample of 52 SPT-SZ clusters, along with X-ray measurements from XMM-Newton. To carry out this test, we need an estimate of the luminosity distance ($D_L$) at the redshift of the cluster. For this purpose, we use three independent methods: directly using $D_L$ from the closest Type Ia Supernovae from the Union 2.1 sample, non-parametric reconstruction of $D_L$ using the same Union 2.1 sample, and finally using $H(z)$ measurements from cosmic chronometers and reconstructing $D_L$ using Gaussian Process regression. We use four d…
We propose a new method to test the cosmic distance duality relation using the strongly lensed gravitational waves. The simultaneous observations of image positions, the relative time delay between different images, the redshift measurements of lens and source, together with the mass modelling of the lens galaxy, provide the angular diameter distance to the gravitational wave source. On the other hand, from the observation of gravitational wave signals the luminosity distance to the source can be obtained. This is to our knowledge the first method to simultaneously measure both the angular dia…
A distance-deviation consistency and model-independent method to test the cosmic distance duality relation (CDDR) is provided. The method is worth attention on two aspects: firstly, a distance-deviation consistency method is used to pair subsamples: instead of pairing subsamples with redshift deviation smaller than a \textbf{value}, say $\left\vert Δz\right\vert <0.005$. The redshift deviation between subsamples decreases with the redshift to ensure the distance deviation stays the same. The method selects more subsamples at high redshift, up to $z=2.16$, and provides 120 subsample pairs. Seco…
In this paper, we propose a new test to the cosmic distance duality relation (CDDR), $D_L=D_A(1+z)^2$, where $D_L$ and $D_A$ are the luminosity and angular diameter distances, respectively. The data used correspond to 61 Type Ia Supernova luminosity distances and $Y_{SZE}-Y_X$ measurements of 61 galaxy clusters obtained by the {\it Planck} mission and the deep XMM-Newton X-ray data, where $Y_{SZE}$ is the integrated comptonization parameter obtained via Sunyaev-Zel'dovich effect observations and $Y_X$ is the X-ray counterpart. More precisely, we use the $Y_{SZE}D_{A}^{2}/C_{XSZE}Y_X$ scaling-r…
Geometry and Morphology of the Cosmic Web: Analyzing Spatial Patterns in the Universe
我们回顾了宇宙网络的分析手段的基础上使用的Delaunay和Voronoi镶嵌的广泛的工具集。宇宙网络是一种突出而普遍的泡沫状模式，物质在其中以几兆秒差距到一百多兆秒差距的尺度组织起来。首先，我们描述了Delaunay Tessellation Field Estimation（DTFE）。DTFE形式主义恢复宇宙物质分布的层次性和各向异性形态。多尺度形态滤波器（MMF）使用DTFE密度场来提取不同的形态元素-细丝，薄片和簇-基于ScaleSpace分析，该分析在一系列尺度上搜索这些形态。随后，我们讨论了分水岭空洞探测器（WVF），它调用离散分水岭变换来识别宇宙物质分布中的空洞。退伍军人联合会能够确定空洞的位置、大小和形状。分水岭变换也是SpineWeb分析宇宙物质分布的关键要素。它允许通过识别奇点和相应的分界线来确定宇宙物质密度场中的脊和连接壁。最后，我们描述的概念Alphashapes评估的宇宙物质分布的拓扑结构。
Many new strong gravitational lensing (SGL) systems have been discovered in the last two decades with the advent of powerful new space and ground-based telescopes. The effect of the lens mass model (usually the power-law mass model) on cosmological parameters constraints has been performed recently in literature. In this paper, by using SGL systems and Supernovae type Ia observations, we explore if the power-law mass density profile ($ρ\propto r^{-γ}$) is consistent with the cosmic distance duality relation (CDDR), $D_L(1+z)^{-2}/D_A=η(z)=1$, by considering different lens mass intervals. { It …
In this paper, we investigate the possible deviations of the cosmic distance duality relation (CDDR) using the combination of the largest SNe Ia (Pantheon) and compact radio quasar (QSO) samples through two model-independent approaches. The deviation of CDDR is written as $D_L(z)/D_A(z)(1+z)^{-2}=η(z)$ and $η(z)=e^{τ(z)/2}$, with the parameterizations of $F_1$ ($τ(z) = 2ε_1 z$) and $F_2$ ($τ(z) = (1+z)^{2ε_2}-1$). Furthermore, in order to compare the two resulting distances, two cosmological-model-independent methods, i.e., the nearby SNe Ia method and the GP method are employed to match the t…
Revisiting the cosmic distance duality relation with machine learning reconstruction methods: the combination of HII galaxies and ultra-compact radio quasars
We use simulated strongly lensed gravitational wave events from the Einstein Telescope to demonstrate how the luminosity and angular diameter distances, $d_L(z)$ and $d_A(z)$ respectively, can be combined to test in a model independent manner for deviations from the cosmic distance duality relation and the standard cosmological model. In particular, we use two machine learning approaches, the Genetic Algorithms and Gaussian Processes, to reconstruct the mock data and we show that both approaches are capable of correctly recovering the underlying fiducial model and can provide percent-level con…
Testing Cosmic Distance Duality Relation and Transparency with DESI DR2
State Key Laboratory of Radio Astronomy and Technology, Xinjiang Astronomical Observatory, Chinese Academy of Sciences（中国科学院新疆天文台射电天文与技术国家重点实验室）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；School of Physics and Electronics, Henan University（河南大学物理与电子学院）；School of Physical Science and Technology, Xinjiang University（新疆大学物理科学与技术学院）；School of Physics and Astronomy, China West Normal University（西华师范大学物理与天文学院）
In this paper, we carry out a new model-independent cosmological test for the cosmic distance duality relation~(CDDR) by combining the latest five baryon acoustic oscillations (BAO) measurements and the Pantheon type Ia supernova (SNIa) sample. Particularly, the BAO measurement from extended Baryon Oscillation Spectroscopic Survey~(eBOSS) data release~(DR) 16 quasar sample at effective redshift $z=1.48$ is used, and two methods, i.e. a compressed form of Pantheon sample and the Artificial Neural Network~(ANN) combined with the binning SNIa method, are applied to overcome the redshift-matching …
The cosmic distance duality relation (CDDR), eta(z)=(1+z)^2 d_A(z)/d_L(z)=1, is one of the most fundamental and crucial formulae in cosmology. This relation couples the luminosity and angular diameter distances, two of the most often used measures of structure in the Universe. We here propose a new model-independent method to test this relation, using strong gravitational lensing (SGL) and the high-redshift quasar Hubble diagram reconstructed with a Bezier parametric fit. We carry out this test without pre-assuming a zero spatial curvature, adopting instead the value Omega_K=0.001 +/- 0.002 op…
Closing the Observational Gap in Cosmic Dynamics: AI-Enabled Reconstruction of the Universe's Vorticity and Rotational Flow Morphology
School of Physics and Astronomy, Sun Yat-Sen University（中山大学物理学院）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；School of Astronomy and Space Sciences, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）；South-Western Institute for Astronomy Research, Yunnan University（云南大学西南天文研究所）；Korea Institute of Advanced Studies (KIAS)（韩国高等科学研究院）；Institute for Astronomy, University of Edinburgh（爱丁堡大学天体物理研究所）；Peng Cheng Laboratory（鹏城实验室）；Institute for Astronomy, The school of Physics, Zhejiang University（浙江大学物理学院天体物理研究所）；Center for Cosmology and Computational Astrophysics, Zhejiang University（浙江大学宇宙学与计算天体物理学中心）；CSST Science Center for the Guangdong–Hong Kong–Macau Greater Bay Area, SYSU（中山大学粤港澳大湾区嫦娥科学中心）
The cosmic distance duality relation (DDR) is constrained from the combination of type-Ia supernovae (SNe Ia) and strong gravitational lensing (SGL) systems using deep learning method. To make use of the full SGL data, we reconstruct the luminosity distance from SNe Ia up to the highest redshift of SGL using deep learning, then it is compared with the angular diameter distance obtained from SGL. Considering the influence of lens mass profile, we constrain the possible violation of DDR in three lens mass models. Results show that in the SIS model and EPL model, DDR is violated at high confidenc…
The cosmic distance relation (DDR) associates the angular diameters distance ($D_A$) and luminosity distance ($D_L$) by a simple formula, i.e., $D_L=(1+z)^2D_A$. The strongly lensed gravitational waves (GWs) provide a unique way to measure $D_A$ and $D_L$ simultaneously to the GW source, hence can be used as probes to test DDR. In this paper, we prospect the use of strongly lensed GW events from the future Einstein Telescope to test DDR. We write the possible deviation of DDR as $(1+z)^2D_A/D_L=η(z)$, and consider two different parametrizations of $η(z)$, namely, $η_1(z)=1+η_0 z$ and $η_2(z)=1…
The cosmic distance duality relation (CDDR) has been test through several astronomical observations in the last years. This relation establishes a simple equation relating the angular diameter ($D_A$) and luminosity ($D_L$) distances at a redshift $z$, $D_LD_A^{-1}(1+z)^{-2}=η=1$. However, only very recently this relation has been observationally tested at high redshifts ($z \approx 3.6$) by using luminosity distances from type Ia supernovae (SNe Ia) and gamma ray bursts (GRBs) plus angular diameter distances from strong gravitational lensing (SGL) observations. The results show that no signif…
Instituto de Física Teórica UAM-CSIC（UAM-CSIC理论物理研究所）；Universidad Autónoma de Madrid（马德里自治大学）；University of Oxford（牛津大学）；Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学宇宙研究机构与物理数学国际研究中心卡弗里宇宙起源与演化前沿中心）；Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo（东京大学宇宙研究机构与物理数学国际研究中心卡弗里宇宙起源与演化前沿中心数据驱动发现中心）
