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相关论文: New constraints on primordial non-Gaussianity from…

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In contrast to the large-scale primordial power spectrum $\mathcal{P}_{\zeta}(k)$ and primordial non-Gaussianity $f_{\mathrm{NL}}$, which are strictly constrained, the small-scale $\mathcal{P}_{\zeta}(k)$ and $f_{\mathrm{NL}}$ remain less…

宇宙学与河外天体物理 · 物理学 2025-08-26 Jing-Zhi Zhou , Zhi-Chao Li , Di Wu

The scalar-induced gravitational waves (SIGW), arising from large amplitude primordial density fluctuations, provide a unique observational test for directly probing the epoch of inflation. In this work, we provide constraints on the SIGW…

宇宙学与河外天体物理 · 物理学 2024-07-09 Ryoto Inui , Santiago Jaraba , Sachiko Kuroyanagi , Shuichiro Yokoyama

Investigation of primordial non-Gaussianity holds immense importance in testing the inflation paradigm and shedding light on the physics of the early Universe. In this study, we conduct the complete analysis of scalar-induced gravitational…

宇宙学与河外天体物理 · 物理学 2025-03-21 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

We place new constraints on the primordial local non-Gaussianity parameter f_NL using recent Cosmic Microwave Background anisotropy and galaxy clustering data. We model the galaxy power spectrum according to the halo model, accounting for a…

宇宙学与河外天体物理 · 物理学 2014-11-20 Francesco De Bernardis , Paolo Serra , Asantha Cooray , Alessandro Melchiorri

We constrain the primordial non-Gaussianity parameter of the local model f_{NL} using the skewness power spectrum associated with the two-to-one cumulant correlator of cosmic microwave background temperature anisotropies. This…

宇宙学与河外天体物理 · 物理学 2010-07-22 Joseph Smidt , Alexandre Amblard , Paolo Serra , Asantha Cooray

We present an analysis of the constraints on the amplitude of primordial non-Gaussianity of local type described by the dimensionless parameter $f_{\rm NL}$. These constraints are set by the auto-correlation functions (ACFs) of two large…

宇宙学与河外天体物理 · 物理学 2010-08-11 Jun-Qing Xia , Anna Bonaldi , Carlo Baccigalupi , Gianfranco De Zotti , Sabino Matarrese , Licia Verde , Matteo Viel

Produced nonlinearly by the enhanced linear cosmological curvature perturbations, the scalar-induced gravitational waves (SIGWs) can serve as a potentially powerful probe of primordial non-Gaussianity (PNG) in the early Universe. In this…

宇宙学与河外天体物理 · 物理学 2026-04-14 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

We investigate whether an Early-Universe stochastic gravitational-wave background (SGWB) can account for the common spectrum process reported by NANOGrav, while also being consistent with current and projected CMB measurements of extra…

宇宙学与河外天体物理 · 物理学 2025-09-18 Ido Ben-Dayan , Utkarsh Kumar , Amresh Verma

The stochastic gravitational-wave background originating from cosmic sources contains vital information about the early universe. In this work, we comprehensively study the cross-correlations between the energy-density anisotropies in…

宇宙学与河外天体物理 · 物理学 2025-12-16 Zhi-Chao Zhao , Sai Wang , Jun-Peng Li , Kazunori Kohri

Studying the primordial non-Gaussianity of inflationary perturbations is crucial for testing the inflation paradigm of the early universe. In this work, we conduct a comprehensive analysis of the angular bispectrum and trispectrum of…

宇宙学与河外天体物理 · 物理学 2024-05-30 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

When constraining the primordial non-Gaussianity parameter f_NL with cosmic microwave background anisotropy maps, the bias resulting from the covariance between primordial non-Gaussianity and secondary non-Gaussianities to the estimator of…

天体物理学 · 物理学 2008-11-26 Paolo Serra , Asantha Cooray

The recent stochastic signal observed jointly by NANOGrav, PPTA, EPTA, and CPTA can be accounted for by scalar-induced gravitational waves (SIGWs). The source of the SIGWs is from the primordial curvature perturbations, and the main…

广义相对论与量子宇宙学 · 物理学 2024-01-11 Qin Fei

Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from COBE data in 2002, observations of the CMB have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity…

宇宙学与河外天体物理 · 物理学 2015-03-13 Eiichiro Komatsu

We present limits to the amplitude of non-Gaussian primordial fluctuations in the WMAP 1-year cosmic microwave background sky maps. A non-linear coupling parameter, f_NL, characterizes the amplitude of a quadratic term in the primordial…

The stochastic gravitational wave background (SGWB) provides a unique opportunity to probe the early Universe, potentially encoding information about the primordial curvature power spectrum and the energy scale of reheating. Recent…

宇宙学与河外天体物理 · 物理学 2024-07-23 Lele Fan , Jie Zheng , Fengge Zhang , Zhi-Qiang You

Primordial non-Gaussianity encodes vital information of the physics of the early universe, particularly during the inflationary epoch. To explore the local-type primordial non-Gaussianity $f_{\mathrm{NL}}$, we study the anisotropies in…

宇宙学与河外天体物理 · 物理学 2025-03-25 Jun-Peng Li , Sai Wang , Zhi-Chao Zhao , Kazunori Kohri

We present constraints on the non-linear coupling parameter fnl with the Wilkinson Microwave Anisotropy Probe (WMAP) data. We use the method based on the spherical Mexican hat wavelet (SMHW) to measure the fnl parameter for three of the…

宇宙学与河外天体物理 · 物理学 2015-05-28 A. Curto , E. Martinez-Gonzalez , R. B. Barreiro , M. P. Hobson

In this letter we present constraints on the scale-dependent "local" type primordial non-Gaussianity, which is described by non-Gaussianity's spectral index $n_{\rm NG}$, from the NRAO VLA Sky Survey and the quasar catalog of the Sloan…

宇宙学与河外天体物理 · 物理学 2020-01-08 Ji-Ping Dai , Jun-Qing Xia

The detection of a stochastic signal by recent pulsar timing array (PTA) collaborations, including NANOGrav, PPTA, EPTA+InPTA, CPTA and MPTA, has opened a new window to explore gravitational waves (GWs) at nanohertz frequencies. Motivated…

宇宙学与河外天体物理 · 物理学 2025-04-17 Zhi-Zhang Peng , You Wu , Lang Liu

We revisit the possibility that the stochastic common-spectrum process recently detected by the NANOGrav pulsar timing array experiment could be due to primordial gravitational waves (GWs). A na\"{i}ve extrapolation down to interferometer…

宇宙学与河外天体物理 · 物理学 2022-02-14 Micol Benetti , Leila Lobato Graef , Sunny Vagnozzi
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