Journal of Cosmology and Astroparticle Physics最新文献

{"title":"Stable wormholes in conformal gravity","authors":"Mariano Cadoni, Leonardo Modesto, Mirko Pitzalis and Andrea P. Sanna","doi":"10.1088/1475-7516/2025/06/016","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/016","url":null,"abstract":"We present a class of Lorentzian traversable wormholes in conformal gravity, constructed via Weyl rescaling of Minkowski spacetime. As a result, these wormholes are solutions of every theory of gravity that is both conformally invariant and admits Minkowski spacetime as a solution. We specifically examine the case of a wormhole possessing a Morris-Thorne shape function, arising as a solution of a scalar-tensor conformally invariant theory of gravity. We show that these solutions represent regular, traversable wormholes that are also stable at the linear perturbation level. We argue that, when the Weyl symmetry is spontaneously broken, the broken symmetry phase may lead to a stable “wormhole phase” alternative to the flat “Minkowski phase”.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"51 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144238226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Ly-α 1D bispectrum measurement in eBOSS","authors":"Rodrigo de la Cruz, Gustavo Niz, Vid Iršič, Corentin Ravoux, César Ramírez and Hiram K. Herrera-Alcantar","doi":"10.1088/1475-7516/2025/06/015","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/015","url":null,"abstract":"We present the first robust measurement of the one-dimensional Lyman alpha (Ly-α) forest bispectrum using the complete extended Baryon Oscillation Spectroscopic Survey (eBOSS) quasar sample, corresponding to the sixteenth data release (DR16) of the Sloan Digital Sky Survey (SDSS). The measurement employs an FFT estimator over 12 redshift bins, ranging from z = 2.2 to z = 4.4, and extends to scales of 0.017 (km/s)-1. The used sample consists of 122,066 quasar spectra; however, only the first six redshift bins contain sufficient data to extract a physical bispectrum. To validate and correct the bispectrum measurement, we use synthetic datasets generated from lognormal and 2LPT mocks. Additionally, we detect clear evidence of correlations between SiIII absorption lines and the Ly-α forest within the bispectrum signal, which we model using an extension of the approach applied to the analogous one-dimensional power spectrum signal. In this context, the pipeline developed for this study addresses the impact of instrumental and methodological systematics and is ready for application to larger spectroscopic datasets, such as those from the Dark Energy Spectroscopic Instrument (DESI). Finally, we compare the signal to a simple perturbation theory model, where a χ2 analysis shows a reasonable fit for specific bispectrum configurations with z ≤ 3.2; suggesting that higher-order one-dimensional statistics in the Ly-α forest can complement cosmological inference based on the power spectrum in future analyses.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"34 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GalSBI: phenomenological galaxy population model for cosmology using simulation-based inference","authors":"Silvan Fischbacher, Tomasz Kacprzak, Luca Tortorelli, Beatrice Moser, Alexandre Refregier, Patrick Gebhardt and Daniel Gruen","doi":"10.1088/1475-7516/2025/06/007","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/007","url":null,"abstract":"We present GalSBI, a phenomenological model of the galaxy population for cosmological applications using simulation-based inference. The model is based on analytical parametrizations of galaxy luminosity functions, morphologies and spectral energy distributions. Model constraints are derived through iterative Approximate Bayesian Computation, by comparing Hyper Suprime-Cam deep field images with simulations which include a forward model of instrumental, observational and source extraction effects. We developed an emulator trained on image simulations using a normalizing flow. We use it to accelerate the inference by predicting detection probabilities, including blending effects and photometric properties of each object, while accounting for background and PSF variations. This enables robustness tests for all elements of the forward model and the inference. The model demonstrates excellent performance when comparing photometric properties from simulations with observed imaging data for key parameters such as magnitudes, colors and sizes. The redshift distribution of simulated galaxies agrees well with high-precision photometric redshifts in the COSMOS field within 1.5σ for all magnitude cuts. Additionally, we demonstrate how GalSBI's redshifts can be utilized for splitting galaxy catalogs into tomographic bins, highlighting its potential for current and upcoming surveys. GalSBI is fully open-source, with the accompanying Python package, galsbi (https://cosmo-docs.phys.ethz.ch/galsbi/), offering an easy interface to quickly generate realistic, survey-independent galaxy catalogs.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"2 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spherically symmetric curved spacetimes with a continuum of light rings","authors":"Shahar Hod","doi":"10.1088/1475-7516/2025/06/006","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/006","url":null,"abstract":"Highly curved spacetimes of compact astrophysical objects are known to possess light rings (null circular geodesics) with discrete radii on which massless particles can perform closed circular motions. In the present compact paper, we reveal the existence of spherically symmetric isotropic curved spacetimes that possess light disks which are made of a continuum of closed light rings. In particular, using analytical techniques which are based on the non-linearly coupled Einstein-matter field equations, we prove that these physically intriguing spacetimes contain a central compact core of radius r- > 0 that supports an outer spherical shell with an infinite number (a continuum) of null circular geodesics which are all characterized by the functional relations 4πr2γp(rγ) = 1 - 3m(rγ)/rγ and 8πr2γ(ρ+p) = 1 for rγ ∈ [r-,r+] [here {ρ,p} are respectively the energy density and the isotropic pressure of the self-gravitating matter fields and m(r) is the gravitational mass contained within the sphere of radius r].","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"39 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmic shimmering: the gravitational wave signal of time-resolved cosmic shear observations","authors":"Giorgio Mentasti and Carlo Contaldi","doi":"10.1088/1475-7516/2025/06/013","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/013","url":null,"abstract":"We introduce a novel approach for detecting gravitational waves through their influence on the shape of resolved astronomical objects. This method, complementary to pulsar timing arrays and astrometric techniques, explores the time-dependent distortions caused by gravitational waves on the shapes of celestial bodies, such as galaxies or any resolved extended object. By developing a formalism based on that adopted in the analysis of weak lensing effects, we derive the response functions for gravitational wave-induced distortions and compute their angular correlation functions. Our results highlight the sensitivity of these distortions to the lowest frequencies of the gravitational wave spectrum and demonstrate how they produce distinct angular correlation signatures, including null and polarisation-sensitive correlations. These findings pave the way for future high-resolution surveys to exploit this novel observable, potentially offering new insights into the stochastic gravitational wave background and cosmological models.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model-agnostic basis functions for the 2-point correlation function of dark matter in linear theory","authors":"Aseem Paranjape and Ravi K. Sheth","doi":"10.1088/1475-7516/2025/06/009","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/009","url":null,"abstract":"We consider approximating the linearly evolved 2-point correlation function (2pcf) of dark matter ξlin(r;θ) in a cosmological model with parameters θ as the linear combination ξlin(r;θ)≈∑ibi(r) wi(θ), where the functions ℬ = {bi(r)} form a model-agnostic basis for the linear 2pcf. This decomposition is important for model-agnostic analyses of the baryon acoustic oscillation (BAO) feature in the nonlinear 2pcf of galaxies that fix ℬ and leave the coefficients {wi} free. To date, such analyses have made simple but sub-optimal choices for ℬ, such as monomials. We develop a machine learning framework for systematically discovering a minimal basis ℬ that describes ξlin(r) near the BAO feature in a wide class of cosmological models. We use a custom architecture, denoted BiSequential, for a neural network (NN) that explicitly realizes the separation between r and θ above. The optimal NN trained on data in which only {Ωm,h} are varied in a flat ΛCDM model produces a basis ℬ comprising 9 functions capable of describing ξlin(r) to ∼0.6% accuracy in curved wCDM models varying 7 parameters within ∼5% of their fiducial, flat ΛCDM values. Scales such as the peak, linear point and zero-crossing of ξlin(r) are also recovered with very high accuracy. We compare our approach to other compression schemes in the literature, and speculate that ℬ may also encompass ξlin(r) in modified gravity models near our fiducial ΛCDM model. Replacing the ad hoc bases in model-agnostic BAO analyses with our basis functions can potentially lead to significant gains in constraining power.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Void spin distribution as a powerful probe of σ_8","authors":"Geonwoo Kang and Jounghun Lee","doi":"10.1088/1475-7516/2025/06/011","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/011","url":null,"abstract":"We present a numerical proof of the concept that the void spin distributions can provide a tight constraint on the amplitude of matter density fluctuation on the scale of 8 h-1 Mpc (σ8) without being severely deteriorated by the degeneracies of σ8 with cold dark matter density parameter multiplied by the dimensionless Hubble parameter square (Ωcdmh2), total neutrino mass (Mν) and dark energy equation of state (w). Applying the Void-Finder algorithm [1] to a total of 15 AbacusSummit N-body simulations of 15 different cosmological models [2], we identify the giant voids and measure the magnitudes of rescaled specific angular momenta of point-like void halos as their spins. The 15 cosmologies include the Planck ΛCDM and 14 non-Planck models, each of which differs among one another only in one of {σ8, Ωcdmh2, Mν, w}. We determine the probability density distribution of void spins for each model and for the first time find it to be well approximated by the generalized Gamma distribution with two characteristic parameters, k and θ. It turns out that the best-fit values of k and θ exhibit very sensitive dependence only on σ8, being almost insensitive to Ωcdmh2, Mν and w. This exclusive σ8-dependence of the void spin distributions is confirmed to be robust against the variation of the mass and number cuts of void halos. We also test an observational feasibility of estimating the void spins from real data on the galaxy redshifts.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The sinusoidal valley: a recipe for high peaks in the scalar and induced tensor spectra","authors":"Aris Katsis","doi":"10.1088/1475-7516/2025/06/010","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/010","url":null,"abstract":"Adding a sine-type interaction to inflationary models with two fields can evoke a classical trajectory with many turns in field space. Under conditions we discuss, the enhancement of the spectrum of adiabatic fluctuations resulting from each turn adds up. A special range of scales away from the CMB-constrained region can then be enhanced by several orders of magnitude, allowing for interesting phenomenological possibilities, such as induced gravitational waves or primordial black holes. A localized version of this interaction can also be used as an add-on to conventional inflationary models, thus allowing the injection of the large peak in their power spectra. The intuition and the conclusions drawn from this simple model remain relevant for more complicated applications that usually include extra terms that obscure the simplicity of the mechanism.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"249 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of light sterile neutrinos on cosmological large scale structure","authors":"Rui Hu, Ming-chung Chu, Shek Yeung and Wangzheng Zhang","doi":"10.1088/1475-7516/2025/06/014","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/014","url":null,"abstract":"Sterile neutrinos with masses on the eV scale are promising candidates to account for the origin of neutrino mass and the reactor neutrino anomalies. The mixing between sterile and active neutrinos in the early universe could result in a large abundance of relic sterile neutrinos, which depends on not only their physical mass mphy but also their degree of thermalization, characterized by the extra effective number of relativistic degrees of freedom ΔNeff. Using neutrino-involved N-body simulations, we investigate the effects of sterile neutrinos on the matter power spectrum, halo pairwise velocity, and halo mass and velocity functions. We find that the presence of sterile neutrinos suppress the matter power spectrum and halo mass and velocity functions, but enhance the halo pairwise velocity. We also provide fitting formulae to quantify these effects.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"20 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cosmological constraints from the cross-correlation of DESI Luminous Red Galaxies with CMB lensing from Planck PR4 and ACT DR6","authors":"Noah Sailer, Joshua Kim, Simone Ferraro, Mathew S. Madhavacheril, Martin White, Irene Abril-Cabezas, Jessica Nicole Aguilar, Steven Ahlen, J. Richard Bond, David Brooks, Etienne Burtin, Erminia Calabrese, Shi-Fan Chen, Steve K. Choi, Todd Claybaugh, Kyle Dawson, Axel de la Macorra, Joseph DeRose, Arjun Dey, Biprateep Dey, Peter Doel, Jo Dunkley, Carmen Embil-Villagra, Gerrit S. Farren, Andreu Font-Ribera, Jaime E. Forero-Romero, Enrique Gaztañaga, Vera Gluscevic, Satya Gontcho A. Gontcho, Klaus Honscheid, Cullan Howlett, Stephanie Juneau, David Kirkby, Theodore Kisner, Anthony Kremin, Martin Landriau, Laurent Le Guillou, Michael Levi, Marc Manera, Aaron Meisner, Ramon Miquel, Kavilan Moodley, John Moustakas, Michael D. Niemack, Gustavo Niz, Nathalie Palanque-Delabrouille, Will Percival, Francisco Prada, Frank J. Qu, Graziano Rossi, Eusebio Sanchez, Emmanuel Schaan, Edward Schlafly, David Schlegel, Michael Schubnell, Neelima Sehgal, Hee-Jong Seo, Blake Sherwin, Cristóbal Sifón..","doi":"10.1088/1475-7516/2025/06/008","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/06/008","url":null,"abstract":"We infer the growth of large scale structure over the redshift range 0.4 ≲ z ≲ 1 from the cross-correlation of spectroscopically calibrated Luminous Red Galaxies (LRGs) selected from the Dark Energy Spectroscopic Instrument (DESI) legacy imaging survey with CMB lensing maps reconstructed from the latest Planck and ACT data. We adopt a hybrid effective field theory (HEFT) model that robustly regulates the cosmological information obtainable from smaller scales, such that our cosmological constraints are reliably derived from the (predominantly) linear regime. We perform an extensive set of bandpower- and parameter-level systematics checks to ensure the robustness of our results and to characterize the uniformity of the LRG sample. We demonstrate that our results are stable to a wide range of modeling assumptions, finding excellent agreement with a linear theory analysis performed on a restricted range of scales. From a tomographic analysis of the four LRG photometric redshift bins we find that the rate of structure growth is consistent with ΛCDM with an overall amplitude that is ≃ 5-7% lower than predicted by primary CMB measurements with modest (∼ 2σ) statistical significance. From the combined analysis of all four bins and their cross-correlations with Planck we obtain S8 = 0.765 ± 0.023, which is less discrepant with primary CMB measurements than previous DESI LRG cross Planck CMB lensing results. From the cross-correlation with ACT we obtain S8 = 0.790+0.024-0.027, while when jointly analyzing Planck and ACT we find S8 = 0.775+0.019-0.022 from our data alone and σ8 = 0.772+0.020-0.023 with the addition of BAO data. These constraints are consistent with the latest Planck primary CMB analyses at the ≃ 1.6-2.2σ level, and are in excellent agreement with galaxy lensing surveys.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"20 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144236883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}