The presence of the dark energy allows both the acceleration and the expansion of the universe. In the case of a constant equation of state for dark energy we derived an analytical solution for the Hubble radius in te...The presence of the dark energy allows both the acceleration and the expansion of the universe. In the case of a constant equation of state for dark energy we derived an analytical solution for the Hubble radius in terms of the hypergeometric function. An approximate Taylor expansion of order seven is derived for both the constant and the variable equation of state for dark energy. In the case of the Cardassian cosmology, we also derived an analytical solution for the Hubble radius in terms of the hypergeometric function. The astronomical samples of the distance modulus for Supernova (SN) of type Ia allows the derivation of the involved cosmological in the case of constant equation of state, variable equation of state and Cardassian cosmology.展开更多
In the era of third-generation(3G)gravitational-wave(GW)detectors,GW standard siren observations from binary neutron star mergers provide a powerful tool for probing the expansion history of the universe.Because steri...In the era of third-generation(3G)gravitational-wave(GW)detectors,GW standard siren observations from binary neutron star mergers provide a powerful tool for probing the expansion history of the universe.Because sterile neutrinos can influence cosmic evolution by modifying the radiation content and suppressing structure formation,GW standard sirens offer promising prospects for constraining sterile neutrino properties within a cosmological framework.Building on this,we investigate the prospects of detecting sterile neutrinos in dynamical dark energy(DE)models using joint observations from 3G GW detectors and a future short gamma-ray burst detector,such as a THESEUS-like telescope.We consider the w CDM,holographic DE(HDE),and Chevallier–Polarski–Linder(CPL)models.Our results show that the properties of DE can influence the constraints on sterile neutrino parameters.Moreover,the inclusion of GW data significantly improves constraints on both sterile neutrino parameters and other cosmological parameters across all three models compared to the current limits derived from CMB+BAO+SN(CBS)observations.When GW data are included in the CBS dataset,a preference for△N_(eff)>0 emerges at approximately the 1σlevel in the wCDM and CPL models,while it reaches approximately 3σin the HDE model.Moreover,the upper limits on m_(ν,sterile)^(eff)are reduced by approximately 13%,75%,and 3%in the wCDM,HDE,and CPL models,respectively.展开更多
From recent observational data two significant directions have been made in the field of theoretical cosmology recently. First, we are now able to make use of present observations, such as the Planck and BICEP2 data, ...From recent observational data two significant directions have been made in the field of theoretical cosmology recently. First, we are now able to make use of present observations, such as the Planck and BICEP2 data, to examine theoretical predictions from the standard inflationary ACDM which were made decades of years ago. Second, we can search for new cosmological signatures as a way to explore physics beyond the standard cosmic paradigm. In particular, a subset of early universe models admit a nonsingular bouncing solution that attempts to address the issue of the big bang singularity. These models have achieved a series of considerable developments in recent years, in particular in their perturbative frameworks, which made brand-new predictions of cosmological signatures that could be visible in current and forthcoming observations. Herein we present two representative paradigms of early universe physics. The first is the reputed new matter （or matter-ekpyrotic） bounce scenario in which the universe starts with a matter-dominated contraction phase and transitions into an ekpyrotic phase. In the setting of this paradigm, we have proposed some possible mechanisms of generating a red tilt for primordial curvature perturbations and confront the general predictions with recent cosmological observations. The second is the matter-bounce inflation scenario which can be viewed as an extension of inflationary cosmology with a matter contraction before inflation. We present a class of possible model constructions and review the implications on the current CMB experiments. Lastly a review of significant achievements of these paradigms beyond the inflationary ACDM model is made, which is expected to shed new light on the future direction of observational cosmology.展开更多
We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM mo...We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM model and the holographic dark energy（HDE） model, to make an analysis. The cosmological observations used in this work include the Planck 2015 CMB temperature and polarization data, the baryon acoustic oscillation data, the type Ia supernova data, the Hubble constant direct measurement data, and the Planck CMB lensing data. We find that, mν,sterileff〈 0.2675 eV and Neff〈 3.5718 for ΛCDM cosmology, mν,sterileff〈 0.5313 eV and Neff〈 3.5008 for wCDM cosmology, and mν,sterileff〈 0.1989 eV and Neff〈 3.6701 for HDE cosmology, from the constraints of the combination of these data. Thus, without the addition of measurements of growth of structure, only upper limits on both mν,sterileff and Neff can be derived, indicating that no evidence of the existence of a sterile neutrino species with e V-scale mass is found in this analysis. Moreover, compared to the ΛCDM model, in the wCDM model the limit on mν,sterileff becomes much looser, but in the HDE model the limit becomes much tighter. Therefore, the dark energy properties could significantly influence the constraint limits of sterile neutrino parameters.展开更多
Many cosmological measurements today suggest that the Universe is expanding at a constant rate. This is inferred from the observed age versus redshift relationship and various distance indicators, all of which point t...Many cosmological measurements today suggest that the Universe is expanding at a constant rate. This is inferred from the observed age versus redshift relationship and various distance indicators, all of which point to a cosmic equation of state （EoS） p = -ρ/3, where ρ and p are, respectively, the total energy density and pressure of the cosmic fluid. It has recently been shown that this result is not a coincidence and simply confirms the fact that the symmetries in the Friedmann-Robertson-Walker （FRW） metric appear to be viable only for a medium with zero active mass, i.e., ρ ＋ 3p -= 0. In their latest paper, however, Kim, Lasenby and Hobson （2016） have provided what they believe to be a counter argument to this conclusion. Here, we show that these authors are merely repeating the conventional mistake of incorrectly placing the observer simultaneously in a comoving frame, where the lapse function gtt is coordinate dependent when ρ ＋ 3p ≠ 0, and a supposedly different, free- falling frame, in which gtt = i, implying no time dilation. We demonstrate that the Hubble flow is not inertial when ρ ＋ 3p ≠ 0, so the comoving frame is generally not in free fall, even though in FRW, the comoving and free-falling frames are supposed to be identical at every spacetime point. So this confusion of frames not only constitutes an inconsistency with the fundamental tenets of general relativity but, additionally, there is no possibility of using a gauge transformation to select a set of coordinates for which gtt = 1 when ρ＋ 3p ≠ 0.展开更多
In this paper, we propose a novel method using artificial neural networks(ANNs) to reconstruct the global 21 cm signal from measurements of the 21 cm power spectrum. The 21 cm global signal provides crucial informatio...In this paper, we propose a novel method using artificial neural networks(ANNs) to reconstruct the global 21 cm signal from measurements of the 21 cm power spectrum. The 21 cm global signal provides crucial information on cosmic evolution from the Dark Ages through cosmic dawn and the Epoch of Reionization. Single-dish telescopes directly measure the global signal, whereas interferometric experiments primarily measure spatial fluctuations,represented by the 21 cm power spectrum. While no direct mathematical relationship exists between these two observables-since they probe fundamentally independent Fourier modes-they are indirectly linked through their common dependence on underlying astrophysical and cosmological parameters. The ANN effectively learns this implicit, model-dependent relationship, enabling it to predict the global signal from the power spectrum. We demonstrate that the ANN accurately recovers the global 21 cm signal across a broad redshift range(z = 7.5–35)even under realistic observational noise scenarios corresponding to SKA-1 observations. The reconstruction accuracy depends significantly on the spatial scales(wavenumber k) included, with larger-scale modes yielding better results due to their stronger sensitivity to global astrophysical processes. Although the ANN method does not provide a model-independent verification of anomalous observations(e.g., the Experiment to Detect the Global Epoch of Reionization Signature absorption trough), it offers a computationally efficient and robust tool to infer the global signal within the context of standard astrophysical and cosmological models.展开更多
This work aims to investigate the different stability conditions of two scenarios of the inhomogeneous Lemaitre–Tolman–Bond model of the universe with holographic dark energy.We considered the Rényi and Tsallis...This work aims to investigate the different stability conditions of two scenarios of the inhomogeneous Lemaitre–Tolman–Bond model of the universe with holographic dark energy.We considered the Rényi and Tsallis holographic models of interacting dark energy.These holographic models are investigated using the IR cutoff that equals the Hubble horizon.Various stability conditions of these models have been investigated to understand how much these models can tell us about the recent and future epochs of the universe in comparison with the cosmological constant model,orΛCDM model.The conditions of violating the cosmological energy conditions have been studied.The evolution of the entropy and its first and second derivatives have been calculated and plotted for these holographic models.This gives an idea of how far these models satisfy the generalized second law of thermodynamics and hence have thermodynamical stability.The dynamical stability is studied for these evolved models,which give us glimpses of the dynamical stability at different phases of its evolution.We focus on investigating the stability in recent and near future times up to z≤-4.Further investigation of stability has been obtained by studying the evolved sound speed squared parameter for these models,which gave us a final and decisive evaluation of the stability of these models.展开更多
We present constraints on the baryonic matter density parameter,Ωb,within the framework of theΛCDM model.Our analysis utilizes observational data on the effective optical depth from high-redshift quasars.To paramete...We present constraints on the baryonic matter density parameter,Ωb,within the framework of theΛCDM model.Our analysis utilizes observational data on the effective optical depth from high-redshift quasars.To parameterize the photoionization rateΓ-12,we employ a Bézier polynomial.Additionally,we approximate the Hubble parameter at high redshifts as H(z)≈100hΩ_(m)^(1/2)(1+z)^(3/2)kms^(-1)Mpc^(-1).Confidence regions are obtained with h=0.701±0.013 andΩm=0.315,optimized by the Planck mission.The best-fit values are andΩb=0.043_(0.006/^(+0.005))andΩb=0.045_(0.006)/^(+0.004),corresponding to an old data set and a new data set,respectively.We test the non-parametric form ofΓ-12,obtainingΩb=0.048_(-0.003)/^(+0.001).These results are consistent with the findings of Planck at the 1σcon?dence level.Our findings underscore the effectiveness of quasar data sets in constrainingΩb,eliminating the need for independent photoionization rate data.This approach provides detailed cosmic information about baryon density and the photoionization history of the intergalactic medium.展开更多
Background:The I Ching,or the Book of Changes,in the Han Dynasty was mainly based on symbolism and mathematics and was combined with the astronomical calendar that was popular at the time,forming a theory of hexagram ...Background:The I Ching,or the Book of Changes,in the Han Dynasty was mainly based on symbolism and mathematics and was combined with the astronomical calendar that was popular at the time,forming a theory of hexagram Qi(the life force or vital energy,Qi is the dialectical unity of the spirit and matter of the human body and nature)as the main focus.The people of the Han Dynasty believed that the development and changes in cosmic and human society were consistent with the changes in the hexagrams.Therefore,exploring the construction of the theoretical system of medical epistemology by the philosophy of the I Ching will help to inherit better and develop TCM today.Methods:This paper mainly uses the analysis method of literature review,including famous ancient books on TCM from the Han Dynasties to the Song,Yuan,Ming,and Qing Dynasties and the cosmological concept of Yin-Yang,the Five Elements,and the unity of man and nature in Chinese philosophy.Results:This article provides a new explanation of the theory of I Ching in the Han Dynasty on the thinking mode of the epistemology of TCM from three aspects:(1)The“unchangeable”theoretical basis of image-numerical thinking;(2)The“simple”way of life with one Yin and one Yang;and(3)The“cosmology”view of the evolution of life.Conclusion:This shows that TCM,at its inception in the Han Dynasty,consciously used a rational thinking attitude to construct a harmonious and unified cosmic view of life in which heaven,earth,and man are of the same origin and holographic structure.This philosophy of life is that humanity is the comprehensive embodiment and development of the Way of Heaven.It is also the field where TCM,as an original life science,makes fundamental contributions to human health today.However,the specific historical limitations,such as the Han Dynasty’s reliance on cosmological analogies,may lack empirical rigor compared to modern scientific standards.Also,TCM’s subjective interpretations can limit precision.Therefore,integrating TCM’s unique wisdom with modern science methodologies can advance its global relevance in the future.展开更多
While cold dark matter is widely supported by a range of cosmological observations,it encounters several difficulties at smaller scales.These issues have prompted the investigation of various alternative dark matter c...While cold dark matter is widely supported by a range of cosmological observations,it encounters several difficulties at smaller scales.These issues have prompted the investigation of various alternative dark matter candidates,leaving the question“What is dark matter?”still open.In this work,we propose a new cosmological model that considers dark matter as a barotropic fluid with a constant equation of state parameter and interprets dark energy as the phenomenological emergent dark energy rather than a cosmological constant.We then place constraints on our new model using the Planck 2018 Cosmic Microwave Background(CMB)anisotropy measurements,Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument(DESI),the Pantheon Plus(PP)compilation of Type Ia supernovae,and the Redshift Space Distortions(RSD)data from Gold 2018.The results show statistically significant signal for positive dark matter equation of state and square of sound speed w_(dm)=c_(s,dm)^(2)(10^(7) w_(dm)=4.0_(-2.3)^(+2.5)at the 95%confidence level)for the data combination CMB+DESI+PP+RSD.However,Bayesian evidence indicates that this data combination favors theΛCDM model with very strong evidence.展开更多
Galaxy groups are essential for studying the distribution of matter on a large scale in redshift surveys and for deciphering the link between galaxy traits and their associated halos.In this work,we propose a widely a...Galaxy groups are essential for studying the distribution of matter on a large scale in redshift surveys and for deciphering the link between galaxy traits and their associated halos.In this work,we propose a widely applicable method for identifying groups through machine learning techniques in real space,taking into account the impact of redshift distortion.Our methodology involves two neural networks:one is a classification model for identifying central galaxy groups,and the other is a regression model for predicting the mass of these groups.Both models input observable galaxy traits,allowing future applicability to real survey data.Testing on simulated datasets indicates our method accurately identifies over 92%of groups with M_(vir)≥10^(11) h^(−1)M_(⊙),with 80%achieving a membership completeness of at least 80%.The predicted group masses vary by less than 0.3 dex across different mass scales,even in the absence of a priori data.Our network adapts seamlessly to expand to sparse samples with a flux limit of mr<14,to high redshift samples at z=1.08,and to galaxy samples from the TNG300 hydrodynamical simulation without further training.Furthermore,the framework can easily adjust to real surveys by training on redshift-distorted samples without needing parameter changes.Careful consideration of different observational effects in redshift space makes it promising that this method will be applicable to real galaxy surveys.展开更多
We examine the consequences of the dark matter halo presence on the alignment of angular momenta of the luminous astronomical objects like galaxies and their clusters.For that we calculate the distribution function of...We examine the consequences of the dark matter halo presence on the alignment of angular momenta of the luminous astronomical objects like galaxies and their clusters.For that we calculate the distribution function of their gravitational fields within the statistical method,generalized to the the presence of dark matter halos.The generalization deals both with direct account for halo component in the form of Navarro,Frenk and White(NFW)profile and indirect influence of dark matter on the tidal interaction between luminous objects.The NFW profile s gravitational field distribution isolates luminous objects within the halo,suppressing mutual interactions,which contradicts observational data and simulations.To address this,we propose a hypothetical short-range interaction,which can be a well of Newtonian(gravitational)nature.Namely,we derive this short-range interaction on the basis of a multipole expansion of the initial Newtonian interaction.Introducing the short-range part in the initial interaction,we arrive at modified quadrupolar intergalaxy interaction,which permits the luminous objects,which are closer than interaction range rc,to effectively interact with each other inside the dark matter halo.This permits us to show that the more clumpy the luminous objects are,the more probably their orbital moments will be aligned.Our theoretical analysis,supported by observational and simulation data(Illustris Project 2013),indicates that dark matter halos significantly alter the gravitational field distribution,affecting angular momenta alignment.We find that while angular momenta alignment increases with cluster richness in galaxy clusters,it does not in superclusters,likely due to the abundant dark matter in superclusters.Our theoretical predictions align well with both observational data and numerical simulations.展开更多
The effective field theory of dark energy(EFTofDE)provides a systematic and model-independent framework to study dark energy(DE)and modified gravity(MG)with one additional scalar degree of freedom.It can describe the ...The effective field theory of dark energy(EFTofDE)provides a systematic and model-independent framework to study dark energy(DE)and modified gravity(MG)with one additional scalar degree of freedom.It can describe the known models such as Quintessence,k-essence,DGP,f(R),and Horndeski theories.In this work,we update constraints on EFTofDE by utilizing the most up-to-date public data including the Baryon Acoustic Oscillations(DESI DR2),CMB(Planck 2018 and ACT DR6),SNIa(DESY5),weak lensing(DESY3)and full-shape galaxy power(BOSS DR 12).We find with the ACDM background,general relativity(GR)is favored by the data,while with the w_(0)w_(a)CDM background,slight modification to GR is favored,but still consistent with GR within 1.5σ.We also find the significance level for dynamical DE is greatly reduced within EFTofDE compared to within GR,indicating the degeneracy between dynamical DE and MG.展开更多
The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal ...The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal physical processes during solar flares.Before launch,Geant4 simulations were employed to assess the onorbit background of the HXI instrument,evaluating its performance and potential to achieve its scientific objectives.This study addresses issues identified in previous simulations and conducts further analyses to examine the distribution of background counts across the 99 detectors.The results demonstrate alignment between simulations and observations at low and medium geomagnetic latitudes;however,challenges persist at high geomagnetic latitudes due to limitations in the current albedo photon model.This investigation provides insights into background sources from various particles,enhances understanding of space background characteristics,and offers guidance for background subtraction in imaging processes.展开更多
In this study,we investigate the potential of mark-weighted angular correlation functions,which integrateβ-cosmic-web classification with angular correlation function analysis to improve cosmological constraints.Usin...In this study,we investigate the potential of mark-weighted angular correlation functions,which integrateβ-cosmic-web classification with angular correlation function analysis to improve cosmological constraints.Using SDSS DR12 CMASS-NGC galaxies and mock catalogs withΩ_(m)varying from 0.25 to 0.40,we assess the discriminative power of different statistics via the average improvement in chi-squared,ΔX^(2),across six redshift bins.This metric quantifies how effectively each statistic distinguishes between different cosmological models.Incorporating cosmic-web weights leads to substantial improvements.Using statistics weighted by the mean neighbor distance(Dnei)increasesΔX^(2)by approximately 40%–130%,while applying inverse mean neighbor distance weighting(1/Dnei)yields even larger gains,boostingΔX^(2)by a factor of 2–3 compared to traditional unweighted angular statistics.These enhancements are consistent with previous 3D clustering results,demonstrating the superior sensitivity of theβ-weighted approaches.Our method,based on thin redshift slices,is particularly suitable for slitless surveys(e.g.,Euclid,CSST)where redshift uncertainties limit 3D analyses.This study also offers a framework for applying marked statistics to 2D angular clustering.展开更多
Background:This essay mainly explores the theoretical roots of traditional Chinese medicine(TCM)practice in the Han Dynasty.It places individual small lives in the big life of heaven,earth and the universe and looks a...Background:This essay mainly explores the theoretical roots of traditional Chinese medicine(TCM)practice in the Han Dynasty.It places individual small lives in the big life of heaven,earth and the universe and looks at life’s occurrence,development and death from a broader cosmology perspective,and thus provide the“Great Harmony between Heaven and Human”in the Huangdi Neijing(Inner Canon of the Yellow Emperor)of the Han Dynasty.Methods:This paper mainly uses the analysis method of literature review and philosophical concepts.It uses the image-number logic thinking method of I Ching to compare images with analogy and the holistic thinking method of the three-talent view of heaven,earth,and man to understand life.Results:It is mainly reflected in three aspects:(1)One Yin and one Yang are called Tao((1)Yin Yang as the coherent fabric of nature and mind,exhibited in all existence,(2)Yin Yang as Jiao(interaction)between the waxing and waning of the cosmic and human realms,and(3)Yin Yang as a process of harmonization ensuring a constant,dynamic balance of all things);(2)The way of life in the Book of Changes;and(3)The Unity of the Way of Heaven and the Way of TCM.Conclusion:The main medical thought laid the theoretical foundation of early practice and the development model of life cognition.It is still worthy of continuous exploration,development,and innovation in contemporary philosophy and life sciences.展开更多
In this study,we used thef(T) gravity framework with the energy-momentum tensor for a perfect fluid to derive key cosmological parameters,including the Hubble parameter H,deceleration parameter q and Statefinder diagn...In this study,we used thef(T) gravity framework with the energy-momentum tensor for a perfect fluid to derive key cosmological parameters,including the Hubble parameter H,deceleration parameter q and Statefinder diagnostics.Model parameters were optimized using an R^(2) test,resulting in β=1.312_(-0.014)^(+0.013),ξ=1.273_(-0.0071)^(+0.0065) and H_(0)=72.60_(-0.49)^(+0.50),with an R^(2) of 0.9527.Our model aligns closely with the ACDM model and shows good performance based on AIC and BIC criteria.Analyzing the q(z) curve revealed the transition from deceleration to acceleration in the universe's expansion.Additionally,we examined pressure,energy density,and equation of state parameter for two models,f(T)=λT and f(T)=T+βT^(2),both aligning well with observational data.The r-s and r-q diagnostics further confirm our model's consistency with ΛCDM,making it a strong alternative for explaining cosmic expansion.The evolution of Ω(z) shows strong consistency with the ΛCDM model,with the Om parameter approaching 0.3 at lower redshifts and parameter uncertainties highlighting the model's reliability.展开更多
Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distanc...Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distances,helping to break parameter degeneracies generated by traditional cosmological observations.This advancement can lead to much tighter constraints on sterile neutrino parameters.This work provides a preliminary forecast for detecting sterile neutrinos using third-generation GW detectors in combination with future shortγ-ray burst observations from a THESEUS-like telescope,an approach not previously explored in the literature.Both massless and massive sterile neutrinos are considered within theΛCDM cosmology.We find that using GW data can greatly enhance the detection capability for massless sterile neutrinos,reaching 3σlevel.For massive sterile neutrinos,GW data can also greatly assist in improving the parameter constraints,but it seems that effective detection is still not feasible.展开更多
In this paper,cosmic distance duality relation(CDDR)is probed without considering any background cosmological model.The only a priori assumption is that the Universe is described by the Friedmann–Lema?tre–Robertson...In this paper,cosmic distance duality relation(CDDR)is probed without considering any background cosmological model.The only a priori assumption is that the Universe is described by the Friedmann–Lema?tre–Robertson–Walker(FLRW)metric.The strong gravitational lensing data is used to construct the dimensionless comoving distance function d(z)and latest type Ia supernovae Pantheon+data is used to estimate luminosity distances at the corresponding redshifts z.Using the distance sum rule along null geodesics of the FLRW metric,the CDDR violation is probed in both flat and non-flat spacetime by considering two parametrizations forη(z),the function generally used to probe the possible deviations from CDDR.The results show that CDDR is compatible with the observations at a very high level of confidence for linear parametrization in a flat Universe.In a non-flat Universe too,CDDR is valid within the 1σconfidence interval with a mild dependence ofηon the curvature density parameterΩK.The results for nonlinear parametrization also show no significant deviation from CDDR.展开更多
We present the first high-precision model for the group-scale strong lensing system CASSOWARY 19(CSWA19),utilizing images from the Hubble Space Telescope.Sixteen member galaxies identified via the red-sequence method,...We present the first high-precision model for the group-scale strong lensing system CASSOWARY 19(CSWA19),utilizing images from the Hubble Space Telescope.Sixteen member galaxies identified via the red-sequence method,and the main halo,all modeled as the dual Pseudo Isothermal Elliptical profile,are incorporated into a parametric lens model alongside an external shear field.To model the system,we adopt the PYAUTOLENS software package,employing a progressive search chain strategy for realizing the transition of source model from multiple Sérsic profiles to a brightness-adaptive pixelization,which uses 1000 pixels in the source plane to reconstruct the background source corresponding to 177,144 image pixels in the image plane.Our results indicate that the total mass within the Einstein radius is MθE≈1.41×10^(13)M_(⊙) and the average slope of the total mass density ρ(r)∝r^(−γ) is γ=1.33 within the effective radius.This slope is shallower than those measured in galaxies and groups but is closer to those of galaxy clusters.In addition,our approach successfully resolves the two merging galaxies in the background source and yields a total magnification of μ=-103.18_(-0.19)^(+0.23),which is significantly higher than the outcomes from previous studies of CSWA19.In summary,our research demonstrates the effectiveness of the brightness-adaptive pixelization source reconstruction technique for modeling group-scale strong lensing systems.It can serve as a technical reference for future investigations into pixel-level modeling of the group-and clusterscale strong lensing systems.展开更多
文摘The presence of the dark energy allows both the acceleration and the expansion of the universe. In the case of a constant equation of state for dark energy we derived an analytical solution for the Hubble radius in terms of the hypergeometric function. An approximate Taylor expansion of order seven is derived for both the constant and the variable equation of state for dark energy. In the case of the Cardassian cosmology, we also derived an analytical solution for the Hubble radius in terms of the hypergeometric function. The astronomical samples of the distance modulus for Supernova (SN) of type Ia allows the derivation of the involved cosmological in the case of constant equation of state, variable equation of state and Cardassian cosmology.
基金Supported by the National Natural Science Foundation of China(12305069,11947022,12533001,12575049,12473001)the National SKA Program of China(2022SKA0110200,2022SKA0110203)+2 种基金the China Manned Space Program(CMS-CSST-2025-A02)the National 111 Project(B16009)the Program of the Education Department of Liaoning Province(JYTMS20231695)。
文摘In the era of third-generation(3G)gravitational-wave(GW)detectors,GW standard siren observations from binary neutron star mergers provide a powerful tool for probing the expansion history of the universe.Because sterile neutrinos can influence cosmic evolution by modifying the radiation content and suppressing structure formation,GW standard sirens offer promising prospects for constraining sterile neutrino properties within a cosmological framework.Building on this,we investigate the prospects of detecting sterile neutrinos in dynamical dark energy(DE)models using joint observations from 3G GW detectors and a future short gamma-ray burst detector,such as a THESEUS-like telescope.We consider the w CDM,holographic DE(HDE),and Chevallier–Polarski–Linder(CPL)models.Our results show that the properties of DE can influence the constraints on sterile neutrino parameters.Moreover,the inclusion of GW data significantly improves constraints on both sterile neutrino parameters and other cosmological parameters across all three models compared to the current limits derived from CMB+BAO+SN(CBS)observations.When GW data are included in the CBS dataset,a preference for△N_(eff)>0 emerges at approximately the 1σlevel in the wCDM and CPL models,while it reaches approximately 3σin the HDE model.Moreover,the upper limits on m_(ν,sterile)^(eff)are reduced by approximately 13%,75%,and 3%in the wCDM,HDE,and CPL models,respectively.
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Department of Physics at McGill
文摘From recent observational data two significant directions have been made in the field of theoretical cosmology recently. First, we are now able to make use of present observations, such as the Planck and BICEP2 data, to examine theoretical predictions from the standard inflationary ACDM which were made decades of years ago. Second, we can search for new cosmological signatures as a way to explore physics beyond the standard cosmic paradigm. In particular, a subset of early universe models admit a nonsingular bouncing solution that attempts to address the issue of the big bang singularity. These models have achieved a series of considerable developments in recent years, in particular in their perturbative frameworks, which made brand-new predictions of cosmological signatures that could be visible in current and forthcoming observations. Herein we present two representative paradigms of early universe physics. The first is the reputed new matter （or matter-ekpyrotic） bounce scenario in which the universe starts with a matter-dominated contraction phase and transitions into an ekpyrotic phase. In the setting of this paradigm, we have proposed some possible mechanisms of generating a red tilt for primordial curvature perturbations and confront the general predictions with recent cosmological observations. The second is the matter-bounce inflation scenario which can be viewed as an extension of inflationary cosmology with a matter contraction before inflation. We present a class of possible model constructions and review the implications on the current CMB experiments. Lastly a review of significant achievements of these paradigms beyond the inflationary ACDM model is made, which is expected to shed new light on the future direction of observational cosmology.
基金supported by the National Natural Science Foundation of China(Grant Nos.11522540,and 11690021)the National Program for Support of Top-notch Young Professionalsthe Provincial Department of Education of Liaoning(Grant No.L2012087)
文摘We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM model and the holographic dark energy（HDE） model, to make an analysis. The cosmological observations used in this work include the Planck 2015 CMB temperature and polarization data, the baryon acoustic oscillation data, the type Ia supernova data, the Hubble constant direct measurement data, and the Planck CMB lensing data. We find that, mν,sterileff〈 0.2675 eV and Neff〈 3.5718 for ΛCDM cosmology, mν,sterileff〈 0.5313 eV and Neff〈 3.5008 for wCDM cosmology, and mν,sterileff〈 0.1989 eV and Neff〈 3.6701 for HDE cosmology, from the constraints of the combination of these data. Thus, without the addition of measurements of growth of structure, only upper limits on both mν,sterileff and Neff can be derived, indicating that no evidence of the existence of a sterile neutrino species with e V-scale mass is found in this analysis. Moreover, compared to the ΛCDM model, in the wCDM model the limit on mν,sterileff becomes much looser, but in the HDE model the limit becomes much tighter. Therefore, the dark energy properties could significantly influence the constraint limits of sterile neutrino parameters.
文摘Many cosmological measurements today suggest that the Universe is expanding at a constant rate. This is inferred from the observed age versus redshift relationship and various distance indicators, all of which point to a cosmic equation of state （EoS） p = -ρ/3, where ρ and p are, respectively, the total energy density and pressure of the cosmic fluid. It has recently been shown that this result is not a coincidence and simply confirms the fact that the symmetries in the Friedmann-Robertson-Walker （FRW） metric appear to be viable only for a medium with zero active mass, i.e., ρ ＋ 3p -= 0. In their latest paper, however, Kim, Lasenby and Hobson （2016） have provided what they believe to be a counter argument to this conclusion. Here, we show that these authors are merely repeating the conventional mistake of incorrectly placing the observer simultaneously in a comoving frame, where the lapse function gtt is coordinate dependent when ρ ＋ 3p ≠ 0, and a supposedly different, free- falling frame, in which gtt = i, implying no time dilation. We demonstrate that the Hubble flow is not inertial when ρ ＋ 3p ≠ 0, so the comoving frame is generally not in free fall, even though in FRW, the comoving and free-falling frames are supposed to be identical at every spacetime point. So this confusion of frames not only constitutes an inconsistency with the fundamental tenets of general relativity but, additionally, there is no possibility of using a gauge transformation to select a set of coordinates for which gtt = 1 when ρ＋ 3p ≠ 0.
基金supported by the National SKA Program of China(No.2020SKA0110401)the National Natural Science Foundation of China(NSFC,grant No.12103044).
文摘In this paper, we propose a novel method using artificial neural networks(ANNs) to reconstruct the global 21 cm signal from measurements of the 21 cm power spectrum. The 21 cm global signal provides crucial information on cosmic evolution from the Dark Ages through cosmic dawn and the Epoch of Reionization. Single-dish telescopes directly measure the global signal, whereas interferometric experiments primarily measure spatial fluctuations,represented by the 21 cm power spectrum. While no direct mathematical relationship exists between these two observables-since they probe fundamentally independent Fourier modes-they are indirectly linked through their common dependence on underlying astrophysical and cosmological parameters. The ANN effectively learns this implicit, model-dependent relationship, enabling it to predict the global signal from the power spectrum. We demonstrate that the ANN accurately recovers the global 21 cm signal across a broad redshift range(z = 7.5–35)even under realistic observational noise scenarios corresponding to SKA-1 observations. The reconstruction accuracy depends significantly on the spatial scales(wavenumber k) included, with larger-scale modes yielding better results due to their stronger sensitivity to global astrophysical processes. Although the ANN method does not provide a model-independent verification of anomalous observations(e.g., the Experiment to Detect the Global Epoch of Reionization Signature absorption trough), it offers a computationally efficient and robust tool to infer the global signal within the context of standard astrophysical and cosmological models.
文摘This work aims to investigate the different stability conditions of two scenarios of the inhomogeneous Lemaitre–Tolman–Bond model of the universe with holographic dark energy.We considered the Rényi and Tsallis holographic models of interacting dark energy.These holographic models are investigated using the IR cutoff that equals the Hubble horizon.Various stability conditions of these models have been investigated to understand how much these models can tell us about the recent and future epochs of the universe in comparison with the cosmological constant model,orΛCDM model.The conditions of violating the cosmological energy conditions have been studied.The evolution of the entropy and its first and second derivatives have been calculated and plotted for these holographic models.This gives an idea of how far these models satisfy the generalized second law of thermodynamics and hence have thermodynamical stability.The dynamical stability is studied for these evolved models,which give us glimpses of the dynamical stability at different phases of its evolution.We focus on investigating the stability in recent and near future times up to z≤-4.Further investigation of stability has been obtained by studying the evolved sound speed squared parameter for these models,which gave us a final and decisive evaluation of the stability of these models.
基金supported by the National SKA Program of China(2022SKA0110202)China Manned Space Program through its Space Application System。
文摘We present constraints on the baryonic matter density parameter,Ωb,within the framework of theΛCDM model.Our analysis utilizes observational data on the effective optical depth from high-redshift quasars.To parameterize the photoionization rateΓ-12,we employ a Bézier polynomial.Additionally,we approximate the Hubble parameter at high redshifts as H(z)≈100hΩ_(m)^(1/2)(1+z)^(3/2)kms^(-1)Mpc^(-1).Confidence regions are obtained with h=0.701±0.013 andΩm=0.315,optimized by the Planck mission.The best-fit values are andΩb=0.043_(0.006/^(+0.005))andΩb=0.045_(0.006)/^(+0.004),corresponding to an old data set and a new data set,respectively.We test the non-parametric form ofΓ-12,obtainingΩb=0.048_(-0.003)/^(+0.001).These results are consistent with the findings of Planck at the 1σcon?dence level.Our findings underscore the effectiveness of quasar data sets in constrainingΩb,eliminating the need for independent photoionization rate data.This approach provides detailed cosmic information about baryon density and the photoionization history of the intergalactic medium.
基金the National Social Science Foundation project“Research on Chinese Life Wisdom from the Perspective of Creative Transformation and Innovative Development”(22ZDA082).
文摘Background:The I Ching,or the Book of Changes,in the Han Dynasty was mainly based on symbolism and mathematics and was combined with the astronomical calendar that was popular at the time,forming a theory of hexagram Qi(the life force or vital energy,Qi is the dialectical unity of the spirit and matter of the human body and nature)as the main focus.The people of the Han Dynasty believed that the development and changes in cosmic and human society were consistent with the changes in the hexagrams.Therefore,exploring the construction of the theoretical system of medical epistemology by the philosophy of the I Ching will help to inherit better and develop TCM today.Methods:This paper mainly uses the analysis method of literature review,including famous ancient books on TCM from the Han Dynasties to the Song,Yuan,Ming,and Qing Dynasties and the cosmological concept of Yin-Yang,the Five Elements,and the unity of man and nature in Chinese philosophy.Results:This article provides a new explanation of the theory of I Ching in the Han Dynasty on the thinking mode of the epistemology of TCM from three aspects:(1)The“unchangeable”theoretical basis of image-numerical thinking;(2)The“simple”way of life with one Yin and one Yang;and(3)The“cosmology”view of the evolution of life.Conclusion:This shows that TCM,at its inception in the Han Dynasty,consciously used a rational thinking attitude to construct a harmonious and unified cosmic view of life in which heaven,earth,and man are of the same origin and holographic structure.This philosophy of life is that humanity is the comprehensive embodiment and development of the Way of Heaven.It is also the field where TCM,as an original life science,makes fundamental contributions to human health today.However,the specific historical limitations,such as the Han Dynasty’s reliance on cosmological analogies,may lack empirical rigor compared to modern scientific standards.Also,TCM’s subjective interpretations can limit precision.Therefore,integrating TCM’s unique wisdom with modern science methodologies can advance its global relevance in the future.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(grant No.2024A1515012573)National key R&D Program of China(grant No.2020YFC2201600)+1 种基金National Natural Science Foundation of China(NSFC,grant No.12073088)National SKA Program of China(grant No.2020SKA0110402)。
文摘While cold dark matter is widely supported by a range of cosmological observations,it encounters several difficulties at smaller scales.These issues have prompted the investigation of various alternative dark matter candidates,leaving the question“What is dark matter?”still open.In this work,we propose a new cosmological model that considers dark matter as a barotropic fluid with a constant equation of state parameter and interprets dark energy as the phenomenological emergent dark energy rather than a cosmological constant.We then place constraints on our new model using the Planck 2018 Cosmic Microwave Background(CMB)anisotropy measurements,Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument(DESI),the Pantheon Plus(PP)compilation of Type Ia supernovae,and the Redshift Space Distortions(RSD)data from Gold 2018.The results show statistically significant signal for positive dark matter equation of state and square of sound speed w_(dm)=c_(s,dm)^(2)(10^(7) w_(dm)=4.0_(-2.3)^(+2.5)at the 95%confidence level)for the data combination CMB+DESI+PP+RSD.However,Bayesian evidence indicates that this data combination favors theΛCDM model with very strong evidence.
基金supported by the National Key R&D Program of China(2022YFA1602901)the National Natural Science Foundation of China(NSFC,grant Nos.11988101,11873051,12125302,and 11903043)+2 种基金CAS Project for Young Scientists in Basic Research(grant No.YSBR-062)the China Manned Space Program(grant Nos.CMS-CSST-2025-A03 and CMSCSST-2025-A10)the K.C.Wong Education Foundation.
文摘Galaxy groups are essential for studying the distribution of matter on a large scale in redshift surveys and for deciphering the link between galaxy traits and their associated halos.In this work,we propose a widely applicable method for identifying groups through machine learning techniques in real space,taking into account the impact of redshift distortion.Our methodology involves two neural networks:one is a classification model for identifying central galaxy groups,and the other is a regression model for predicting the mass of these groups.Both models input observable galaxy traits,allowing future applicability to real survey data.Testing on simulated datasets indicates our method accurately identifies over 92%of groups with M_(vir)≥10^(11) h^(−1)M_(⊙),with 80%achieving a membership completeness of at least 80%.The predicted group masses vary by less than 0.3 dex across different mass scales,even in the absence of a priori data.Our network adapts seamlessly to expand to sparse samples with a flux limit of mr<14,to high redshift samples at z=1.08,and to galaxy samples from the TNG300 hydrodynamical simulation without further training.Furthermore,the framework can easily adjust to real surveys by training on redshift-distorted samples without needing parameter changes.Careful consideration of different observational effects in redshift space makes it promising that this method will be applicable to real galaxy surveys.
文摘We examine the consequences of the dark matter halo presence on the alignment of angular momenta of the luminous astronomical objects like galaxies and their clusters.For that we calculate the distribution function of their gravitational fields within the statistical method,generalized to the the presence of dark matter halos.The generalization deals both with direct account for halo component in the form of Navarro,Frenk and White(NFW)profile and indirect influence of dark matter on the tidal interaction between luminous objects.The NFW profile s gravitational field distribution isolates luminous objects within the halo,suppressing mutual interactions,which contradicts observational data and simulations.To address this,we propose a hypothetical short-range interaction,which can be a well of Newtonian(gravitational)nature.Namely,we derive this short-range interaction on the basis of a multipole expansion of the initial Newtonian interaction.Introducing the short-range part in the initial interaction,we arrive at modified quadrupolar intergalaxy interaction,which permits the luminous objects,which are closer than interaction range rc,to effectively interact with each other inside the dark matter halo.This permits us to show that the more clumpy the luminous objects are,the more probably their orbital moments will be aligned.Our theoretical analysis,supported by observational and simulation data(Illustris Project 2013),indicates that dark matter halos significantly alter the gravitational field distribution,affecting angular momenta alignment.We find that while angular momenta alignment increases with cluster richness in galaxy clusters,it does not in superclusters,likely due to the abundant dark matter in superclusters.Our theoretical predictions align well with both observational data and numerical simulations.
基金supported by the National Key R&D Program of China grant No.2022YFF0503404 and No.2021YFC2203100by the National Natural Science Foundation of China(NSFC,grant Nos.12173036 and 11773024)+2 种基金by the China Manned Space Program with grant No.CMS-CSST-2025-A04by Cyrus Chun Ying Tang Foundationsby the 111 Project for"Observational and Theoretical Research on Dark Matter and Dark Energy"(B23042)。
文摘The effective field theory of dark energy(EFTofDE)provides a systematic and model-independent framework to study dark energy(DE)and modified gravity(MG)with one additional scalar degree of freedom.It can describe the known models such as Quintessence,k-essence,DGP,f(R),and Horndeski theories.In this work,we update constraints on EFTofDE by utilizing the most up-to-date public data including the Baryon Acoustic Oscillations(DESI DR2),CMB(Planck 2018 and ACT DR6),SNIa(DESY5),weak lensing(DESY3)and full-shape galaxy power(BOSS DR 12).We find with the ACDM background,general relativity(GR)is favored by the data,while with the w_(0)w_(a)CDM background,slight modification to GR is favored,but still consistent with GR within 1.5σ.We also find the significance level for dynamical DE is greatly reduced within EFTofDE compared to within GR,indicating the degeneracy between dynamical DE and MG.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.12173100,11973097 and 12022302)the Youth Innovation Promotion Association CAS(Nos.2021317 and Y2021087)+1 种基金the Scientific Instrument Developing Project of the CAS(No.20200077)the Strategic Priority Research Program on Space Science,Chinese Academy of Sciences(No.XDA 15320104).
文摘The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal physical processes during solar flares.Before launch,Geant4 simulations were employed to assess the onorbit background of the HXI instrument,evaluating its performance and potential to achieve its scientific objectives.This study addresses issues identified in previous simulations and conducts further analyses to examine the distribution of background counts across the 99 detectors.The results demonstrate alignment between simulations and observations at low and medium geomagnetic latitudes;however,challenges persist at high geomagnetic latitudes due to limitations in the current albedo photon model.This investigation provides insights into background sources from various particles,enhances understanding of space background characteristics,and offers guidance for background subtraction in imaging processes.
基金supported by the Ministry of Science and Technology of China(2020SKA0110401,2020SKA0110402 and 2020SKA0110100)the National Key Research and Development Program of China(2018YFA0404504,2018YFA0404601 and 2020YFC2201600)+2 种基金the National Natural Science Foundation of China(12373005,11890691,12205388,12220101003 and 12473097)the China Manned Space Project with numbers CMS-CSST-2021(A02,A03,B01)Guangdong Basic and Applied Basic Research Foundation(2024A1515012309)。
文摘In this study,we investigate the potential of mark-weighted angular correlation functions,which integrateβ-cosmic-web classification with angular correlation function analysis to improve cosmological constraints.Using SDSS DR12 CMASS-NGC galaxies and mock catalogs withΩ_(m)varying from 0.25 to 0.40,we assess the discriminative power of different statistics via the average improvement in chi-squared,ΔX^(2),across six redshift bins.This metric quantifies how effectively each statistic distinguishes between different cosmological models.Incorporating cosmic-web weights leads to substantial improvements.Using statistics weighted by the mean neighbor distance(Dnei)increasesΔX^(2)by approximately 40%–130%,while applying inverse mean neighbor distance weighting(1/Dnei)yields even larger gains,boostingΔX^(2)by a factor of 2–3 compared to traditional unweighted angular statistics.These enhancements are consistent with previous 3D clustering results,demonstrating the superior sensitivity of theβ-weighted approaches.Our method,based on thin redshift slices,is particularly suitable for slitless surveys(e.g.,Euclid,CSST)where redshift uncertainties limit 3D analyses.This study also offers a framework for applying marked statistics to 2D angular clustering.
基金The National Social Science Foundation Project“Research on Chinese Life Wisdom from the Perspective of Creative Transformation and Innovative Development”(22ZDA082).
文摘Background:This essay mainly explores the theoretical roots of traditional Chinese medicine(TCM)practice in the Han Dynasty.It places individual small lives in the big life of heaven,earth and the universe and looks at life’s occurrence,development and death from a broader cosmology perspective,and thus provide the“Great Harmony between Heaven and Human”in the Huangdi Neijing(Inner Canon of the Yellow Emperor)of the Han Dynasty.Methods:This paper mainly uses the analysis method of literature review and philosophical concepts.It uses the image-number logic thinking method of I Ching to compare images with analogy and the holistic thinking method of the three-talent view of heaven,earth,and man to understand life.Results:It is mainly reflected in three aspects:(1)One Yin and one Yang are called Tao((1)Yin Yang as the coherent fabric of nature and mind,exhibited in all existence,(2)Yin Yang as Jiao(interaction)between the waxing and waning of the cosmic and human realms,and(3)Yin Yang as a process of harmonization ensuring a constant,dynamic balance of all things);(2)The way of life in the Book of Changes;and(3)The Unity of the Way of Heaven and the Way of TCM.Conclusion:The main medical thought laid the theoretical foundation of early practice and the development model of life cognition.It is still worthy of continuous exploration,development,and innovation in contemporary philosophy and life sciences.
文摘In this study,we used thef(T) gravity framework with the energy-momentum tensor for a perfect fluid to derive key cosmological parameters,including the Hubble parameter H,deceleration parameter q and Statefinder diagnostics.Model parameters were optimized using an R^(2) test,resulting in β=1.312_(-0.014)^(+0.013),ξ=1.273_(-0.0071)^(+0.0065) and H_(0)=72.60_(-0.49)^(+0.50),with an R^(2) of 0.9527.Our model aligns closely with the ACDM model and shows good performance based on AIC and BIC criteria.Analyzing the q(z) curve revealed the transition from deceleration to acceleration in the universe's expansion.Additionally,we examined pressure,energy density,and equation of state parameter for two models,f(T)=λT and f(T)=T+βT^(2),both aligning well with observational data.The r-s and r-q diagnostics further confirm our model's consistency with ΛCDM,making it a strong alternative for explaining cosmic expansion.The evolution of Ω(z) shows strong consistency with the ΛCDM model,with the Om parameter approaching 0.3 at lower redshifts and parameter uncertainties highlighting the model's reliability.
基金supported by the National Natural Science Foundation of China under Grant Nos.12305069,11947022,12473001,11975072,11875102,and 11835009the National SKA Program of China under Grants Nos.2022SKA0110200 and 2022SKA0110203+1 种基金the Program of the Education Department of Liaoning Province under Grant No.JYTMS20231695the National 111 Project under Grant No.B16009。
文摘Sterile neutrinos can influence the evolution of the Universe,and thus cosmological observations can be used to detect them.Future gravitational-wave(GW)observations can precisely measure absolute cosmological distances,helping to break parameter degeneracies generated by traditional cosmological observations.This advancement can lead to much tighter constraints on sterile neutrino parameters.This work provides a preliminary forecast for detecting sterile neutrinos using third-generation GW detectors in combination with future shortγ-ray burst observations from a THESEUS-like telescope,an approach not previously explored in the literature.Both massless and massive sterile neutrinos are considered within theΛCDM cosmology.We find that using GW data can greatly enhance the detection capability for massless sterile neutrinos,reaching 3σlevel.For massive sterile neutrinos,GW data can also greatly assist in improving the parameter constraints,but it seems that effective detection is still not feasible.
文摘In this paper,cosmic distance duality relation(CDDR)is probed without considering any background cosmological model.The only a priori assumption is that the Universe is described by the Friedmann–Lema?tre–Robertson–Walker(FLRW)metric.The strong gravitational lensing data is used to construct the dimensionless comoving distance function d(z)and latest type Ia supernovae Pantheon+data is used to estimate luminosity distances at the corresponding redshifts z.Using the distance sum rule along null geodesics of the FLRW metric,the CDDR violation is probed in both flat and non-flat spacetime by considering two parametrizations forη(z),the function generally used to probe the possible deviations from CDDR.The results show that CDDR is compatible with the observations at a very high level of confidence for linear parametrization in a flat Universe.In a non-flat Universe too,CDDR is valid within the 1σconfidence interval with a mild dependence ofηon the curvature density parameterΩK.The results for nonlinear parametrization also show no significant deviation from CDDR.
基金supported by the National Key Research and Development Program of China(Nos.2023YFB3002501 and 2022YFA1602903)the China Manned Space Project(No.CMS-CSST-2021-A01)+1 种基金the National Natural Science Foundation of China(Nos.12473002 and 11988101)L.W.acknowledges the support from the GHfund A(Nos.202302017475 and 202407017555).
文摘We present the first high-precision model for the group-scale strong lensing system CASSOWARY 19(CSWA19),utilizing images from the Hubble Space Telescope.Sixteen member galaxies identified via the red-sequence method,and the main halo,all modeled as the dual Pseudo Isothermal Elliptical profile,are incorporated into a parametric lens model alongside an external shear field.To model the system,we adopt the PYAUTOLENS software package,employing a progressive search chain strategy for realizing the transition of source model from multiple Sérsic profiles to a brightness-adaptive pixelization,which uses 1000 pixels in the source plane to reconstruct the background source corresponding to 177,144 image pixels in the image plane.Our results indicate that the total mass within the Einstein radius is MθE≈1.41×10^(13)M_(⊙) and the average slope of the total mass density ρ(r)∝r^(−γ) is γ=1.33 within the effective radius.This slope is shallower than those measured in galaxies and groups but is closer to those of galaxy clusters.In addition,our approach successfully resolves the two merging galaxies in the background source and yields a total magnification of μ=-103.18_(-0.19)^(+0.23),which is significantly higher than the outcomes from previous studies of CSWA19.In summary,our research demonstrates the effectiveness of the brightness-adaptive pixelization source reconstruction technique for modeling group-scale strong lensing systems.It can serve as a technical reference for future investigations into pixel-level modeling of the group-and clusterscale strong lensing systems.
