Journal of Cosmology and Astroparticle Physics最新文献_第10页

Accelerating Universe from constraints 从约束中加速宇宙

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-08 DOI: 10.1088/1475-7516/2026/07/034

Anamaria Hell and Misao Sasaki

{"title":"Accelerating Universe from constraints","authors":"Anamaria Hell and Misao Sasaki","doi":"10.1088/1475-7516/2026/07/034","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/034","url":null,"abstract":"We introduce a framework of constrained scalar fields that can give rise to cosmological evolution of the Universe independent of the values of the cosmological constant. Focusing on the simplest realization involving a scalar field with non-minimal coupling, we first study the analytical solutions in the Jordan frame. We show that such solutions include evolution from a radiation dominated-like universe to an exponential expansion, as well as evolution that starts with super-Hubble expansion and then relaxes towards an exponential expansion of the Universe, while describing well-behaved scalar perturbations. We then also relate the theory to the Einstein frame, and analyze the corresponding accelerating solutions. We then consider the model in the presence of external matter. We find that the matter does not affect the evolution of the universe if minimally coupled to the scalar field. In other words, in the Jordan frame, in order to influence the evolution of the space-time, the matter should be non-minimally coupled to the constrained scalar, while it may be minimally coupled to gravity. We show that in this case, the solutions are similar to the free case, and, in addition, allow for the phantom-like equation of state. Finally, we introduce the minimal frame, a frame in which the matter is minimally coupled to both gravity and the constrained scalar, and show that among other possibilities, the phantom-like equation of state can still be realized.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"22 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409107","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}

引用次数: 0

Multi-tracer cross-correlations of the unresolved γ-ray sky 未解析γ射线天空的多示踪相互关系

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-08 DOI: 10.1088/1475-7516/2026/07/035

Bhashin A. Thakore, Marco Regis, Michela Negro, Stefano Camera, Daniel Gruen, Nicolao Fornengo and Aaron J. Roodman

{"title":"Multi-tracer cross-correlations of the unresolved γ-ray sky","authors":"Bhashin A. Thakore, Marco Regis, Michela Negro, Stefano Camera, Daniel Gruen, Nicolao Fornengo and Aaron J. Roodman","doi":"10.1088/1475-7516/2026/07/035","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/035","url":null,"abstract":"Our understanding of the γ-ray sky has greatly advanced, yet studying the unresolved γ-ray background (UGRB) can unveil the nature of the faintest γ-ray source populations in the Universe. Statistical cross-correlations between the UGRB and tracers of large-scale cosmic structure allow us to infer which sources contribute the most to this emission. In this work, we examine the angular correlation between the UGRB and the matter distribution traced by galaxies, using twelve years of Fermi Large Area Telescope (LAT) observations along with three years of Dark Energy Survey (DES) data. We detect a correlation with a signal-to-noise ratio of 7.85, primarily driven by large angular scales. We then perform a multi-tracer analysis that combines this measurement with the cross-correlation between γ rays and DES weak lensing. The two single-tracer results are mutually consistent, and their combination yields a total significance of 10.31, firmly establishing the extragalactic origin of the UGRB. Intriguingly, the properties inferred for the sources contributing to the UGRB show departures from those of the resolved γ-ray population, suggesting that the faint end of the γ-ray sky is not a simple extrapolation of currently resolved sources.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"43 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409108","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}

引用次数: 0

Phantom menace in Palatini f(R,ϕ) theories: Ghost instabilities in the quadratic curvature limit Palatini f（R, φ）理论中的幽灵威胁：二次曲率极限中的幽灵不稳定性

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-08 DOI: 10.1088/1475-7516/2026/07/036

Rahul Thakur, Abhijith Ajith, Sukanta Panda and Archit Vidyarthi

{"title":"Phantom menace in Palatini f(R,ϕ) theories: Ghost instabilities in the quadratic curvature limit","authors":"Rahul Thakur, Abhijith Ajith, Sukanta Panda and Archit Vidyarthi","doi":"10.1088/1475-7516/2026/07/036","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/036","url":null,"abstract":"We investigate general f(R,ϕ) theories in the Palatini formalism with the aim of describing both inflation and late-time cosmic acceleration within a unified framework. Imposing weak-gravity consistency, we show that a tractable Einstein-frame description arises for a R + R2 curvature sector, leading to an effective k-essence theory. We perform a dynamical systems analysis of the post-inflationary evolution and identify a class of critical points associated with accelerated expansion. To close the autonomous dynamical system governing post-inflationary evolution, we employ a late-time adiabatic approximation by imposing that parameters related to scalar potentials remain constant. While this restricts the trajectory as well as observational analysis to a specific class of scalar potentials and non-minimal couplings, we identify a continuous set of non-hyperbolic critical points associated with accelerated expansion. The late-time behavior is, therefore, found to be sensitive to initial conditions. Using late-time observational datasets, including DESI BAO, Cosmic Chronometers, and Type Ia supernovae, we constrain the model and find that while a wide range of trajectories can reproduce the observed expansion history, most suffer from ghost instabilities due to the non-canonical kinetic structure. The only physically viable solution corresponds to a potential-dominated de Sitter phase, which is not dynamically selected as a preferred attractor. These results indicate that perturbative stability significantly restricts Palatini f(R,ϕ) models, challenging their ability to provide a unified cosmological description.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"8 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409139","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}

引用次数: 0

Adiabatic renormalization for modified dispersion relations in cosmology 宇宙学中修正色散关系的绝热重整化

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/029

Christian Durán-Romero, Luis J. Garay, Mercedes Martín-Benito and Rita B. Neves

引用次数: 0

A framework for LISA population inference LISA种群推断的框架

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/025

Alexandre Toubiana and Jonathan R. Gair

{"title":"A framework for LISA population inference","authors":"Alexandre Toubiana and Jonathan R. Gair","doi":"10.1088/1475-7516/2026/07/025","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/025","url":null,"abstract":"The Laser Interferometer Space Antenna (LISA) is expected to have a source rich data stream containing signals from large numbers of many different types of source. This will include both individually resolvable signals and overlapping stochastic backgrounds, a regime intermediate between current ground-based detectors and pulsar timing arrays. The resolved sources and backgrounds will be fitted together in a high dimensional Global Fit. To extract information about the astrophysical populations to which the sources belong, we need to decode the information in the Global Fit, which requires new methodology that has not been required for the analysis of current gravitational wave detectors. Here, we present a hierarchical Bayesian framework to infer the properties of astrophysical populations directly from the output of a LISA Global Fit, consistently accounting for information encoded in both the resolved sources and the unresolved background. Using a simplified model of the Global Fit, we illustrate how the interplay between resolved and unresolved components affects population inference and highlight the impact of data analysis choices, such as the signal-to-noise threshold for resolved sources, on the results. Our approach provides a practical foundation for population inference using LISA data.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"37 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148401067","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}

引用次数: 0

Hubble tension and dark energy in teleparallel Gauss-Bonnet gravity: new constraints from DESI BAO, Pantheon+ and Hubble data 遥平行高斯-邦纳引力中的哈勃张力和暗能量：来自DESI BAO、Pantheon+和哈勃数据的新约束

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/024

Santosh V. Lohakare, S.K. Maurya, Aaisha Al Qassabi and B. Mishra

{"title":"Hubble tension and dark energy in teleparallel Gauss-Bonnet gravity: new constraints from DESI BAO, Pantheon+ and Hubble data","authors":"Santosh V. Lohakare, S.K. Maurya, Aaisha Al Qassabi and B. Mishra","doi":"10.1088/1475-7516/2026/07/024","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/024","url":null,"abstract":"We explore the cosmological dynamics of a teleparallel Gauss-Bonnet gravity model defined by the torsion scalar T and the torsion-based Gauss-Bonnet invariant T𝒢, deriving modified Friedmann equations for a flat FLRW Universe and corresponding linear scalar perturbation equations. Using a numerical approach, we solve these equations for pressureless matter, predicting the redshift evolution of the Hubble parameter H(z). Using a Bayesian Markov chain Monte Carlo analysis based on late-time observations from Cosmic Chronometers, Pantheon+ without SH0ES, and DESI BAO Data Release 1 and Data Release 2, we constrain the model parameters and show that this class of f(T,T𝒢) cosmologies can mimic an effective dark-energy component without introducing an explicit cosmological constant. We further examine the scalar perturbation sector of the posterior-supported cosmological branch and find that the solutions considered in this work remain well-behaved within the adopted perturbative treatment. The model yields a present-day effective equation-of-state parameter in the range ωeff(z = 0) ≈ -0.664 to -0.693, consistent with late-time observations, and shifts the inferred value of H0 toward 69–71.5 km s-1 Mpc-1, suggesting a partial alleviation, though not a complete resolution, of the Hubble tension.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"42 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148401503","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}

引用次数: 0

Constraining dark acoustic oscillations with the high-redshift UV luminosity function 用高红移UV光度函数约束暗声振荡

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/026

Jared Barron, David Curtin, Hongwan Liu, Julian B. Muñoz and Sandip Roy

引用次数: 0

Sahyadri: a simulation suite for the cosmology dependence of the cosmic web Sahyadri：宇宙网络的宇宙学依赖性模拟套件

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/028

Saee Dhawalikar, Shadab Alam, Aseem Paranjape and Arka Banerjee

{"title":"Sahyadri: a simulation suite for the cosmology dependence of the cosmic web","authors":"Saee Dhawalikar, Shadab Alam, Aseem Paranjape and Arka Banerjee","doi":"10.1088/1475-7516/2026/07/028","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/028","url":null,"abstract":"We present Sahyadri, a suite of cosmological N-body simulations designed to enable precision studies of the low-redshift Universe with next-generation spectroscopic surveys. Sahyadri includes systematic variations of four cosmological parameters around Planck 2018 constraints, with seed-matched initial conditions enabling cosmological parameter derivatives. It is planned to ultimately extend to six parameters. Each simulation evolves 20483 particles in a periodic box of side length 200 h-1 Mpc, yielding a particle mass of mp = 8.1 × 107h-1M⊙ in the fiducial Planck 2018 cosmology. This resolution enables robust identification of dark matter halos down to Mmin = 3.2 × 109h-1M⊙, which represents a factor of ∼25 improvement over the AbacusSummit suite, and is over two orders of magnitude better than the Quijote and Aemulus suites. We estimate that approximately 40% of DESI BGS galaxies at redshift z < 0.15 — roughly 1.6 million objects — reside in halos accessible to Sahyadri but beyond the reach of existing parameter-varying simulation suites. We demonstrate Sahyadri's capabilities through measurements of the matter power spectrum, halo mass function and power spectrum, and beyond 2-point statistics such as the Voronoi volume function and kth nearest neighbour statistics, showing excellent agreement with theoretical predictions and significant sensitivity to Ωm variations. We implement a custom compression scheme reducing storage requirements by a factor of ∼3 while maintaining sub-percent clustering accuracy. Key data products will be made publicly available.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148401520","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}

引用次数: 0

Decoupling perturbations from background in f(Q) gravity: the square-root correction and the impact on the σ 8 tension f(Q)重力下背景解耦扰动：平方根修正及对σ 8张力的影响

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-07 DOI: 10.1088/1475-7516/2026/07/027

Chunyu Li, Xin Ren, Yuhang Yang, Emmanuel N. Saridakis, Yi-Fu Cai, Chunyu Li, Xin Ren, Yuhang Yang, Emmanuel N. Saridakis and Yi-Fu Cai

{"title":"Decoupling perturbations from background in f(Q) gravity: the square-root correction and the impact on the σ 8 tension","authors":"Chunyu Li, Xin Ren, Yuhang Yang, Emmanuel N. Saridakis, Yi-Fu Cai, Chunyu Li, Xin Ren, Yuhang Yang, Emmanuel N. Saridakis and Yi-Fu Cai","doi":"10.1088/1475-7516/2026/07/027","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/027","url":null,"abstract":"We investigate a perturbation-level modification of symmetric teleparallel gravity of the form f(Q) = F(Q) + M√(Q) and assess its potential to ease the σ8 tension. The square-root term leaves the background expansion unchanged at the level of FLRW cosmology, while modifying the effective gravitational coupling and thereby providing a decoupling between background evolution and structure-growth. Using the latest redshift-space distortion data, including DESI DR1 Full-Shape measurements, we constrain the model through its impact on the growth observable fσ8(z) across three representative backgrounds: ΛCDM, an H0-tension-reducing model, and a DESI-motivated dynamical dark energy scenario. In all cases, the square-root correction suppresses the growth of structure and induces a degeneracy with σ8, leading to weaker constraints from current data. This allows for a wider range of σ8 values consistent with Planck, with the effect being most pronounced in the H0-tension-oriented background model. However, because RSD data constrain fσ8 rather than σ8 directly, a residual degeneracy between M and σ8 remains, indicating that future multi-probe analyses combining lensing and full-shape clustering will be required to determine whether the √(Q) term represents a genuine signal of modified gravity.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"35 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148401068","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}

引用次数: 0

A new window on dynamical dark energy: combining DESI-DR2 BAO with future gravitational wave observations 动态暗能量的新窗口：DESI-DR2 BAO与未来引力波观测相结合

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2026-07-05 DOI: 10.1088/1475-7516/2026/07/022

Felipe Bruno Medeiros dos Santos, Jonathan Morais, Supriya Pan, Weiqiang Yang and Eleonora Di Valentino

{"title":"A new window on dynamical dark energy: combining DESI-DR2 BAO with future gravitational wave observations","authors":"Felipe Bruno Medeiros dos Santos, Jonathan Morais, Supriya Pan, Weiqiang Yang and Eleonora Di Valentino","doi":"10.1088/1475-7516/2026/07/022","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/07/022","url":null,"abstract":"Baryon acoustic oscillation (BAO) data from the Dark Energy Spectroscopic Instrument (DESI) appear to indicate the first evidence for dynamical dark energy (DDE), with a present-day behavior resembling quintessence. This evidence emerges when the Chevallier-Polarski-Linder (CPL) parameterization of the dark energy equation of state, wde = w0 + wa (1 - a), is considered, and persists across other functional forms of wde. In this work, we investigate how the inclusion of future gravitational wave (GW) standard siren data impacts the uncertainties in cosmological parameters when combined with DESI measurements. Specifically, we analyze the expected contributions from upcoming GW observatories such as the Einstein Telescope (ET) and the Deci-hertz Interferometer Gravitational-wave Observatory (DECIGO), as well as the current Laser Interferometer Gravitational-Wave Observatory (aLIGO). We find that the addition of GW data, particularly from DECIGO, significantly reduces the uncertainties in cosmological parameters, with the extent of the improvement depending on the specific form of wde and being more expressive for the Ωm and H0 parameters for all models studied. Our results highlight both the constraining power of future GW observations and the importance of considering a range of cosmological models in the data analysis.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"22 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148393876","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}

引用次数: 0