Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/067
Chong-Zhi Li, Chen Yuan and Qing-Guo Huang
We give an analytical approximation for the energy spectrum of the scalar-induced gravitational waves (SIGWs) generated by a broken power-law power spectrum, and find that both the asymptotic power-law tails and the intermediate peak contribute distinct features to the SIGW spectrum. Moreover, the broken power-law power spectrum has abundant near-peak features and our results can be used as a near-peak approximation that covers a wide range of models. Our analytical approximation is useful in the rapid generation of the SIGW energy spectrum, which is beneficial for gravitational wave data analysis.
{"title":"Gravitational waves induced by scalar perturbations with a broken power-law peak","authors":"Chong-Zhi Li, Chen Yuan and Qing-Guo Huang","doi":"10.1088/1475-7516/2025/01/067","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/067","url":null,"abstract":"We give an analytical approximation for the energy spectrum of the scalar-induced gravitational waves (SIGWs) generated by a broken power-law power spectrum, and find that both the asymptotic power-law tails and the intermediate peak contribute distinct features to the SIGW spectrum. Moreover, the broken power-law power spectrum has abundant near-peak features and our results can be used as a near-peak approximation that covers a wide range of models. Our analytical approximation is useful in the rapid generation of the SIGW energy spectrum, which is beneficial for gravitational wave data analysis.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"20 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986127","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/071
Hugo Plombat, Théo Simon, Jordan Flitter and Vivian Poulin
We investigate the sensitivity of the 21 cm power spectrum from cosmic dawn and the epoch of reionization to models of free-streaming dark radiation (parameterized through Neff) and interacting dark radiation-dark matter models (DM-DR). The latter models have gained attention for their potential in addressing recent cosmological tensions and structure formation challenges. We perform a Fisher matrix analysis under different assumptions regarding the astrophysical modeling, and forecast the sensitivity of HERA observations, combined with CMB data from Planck and the Simons Observatory (SO), to Neff and DM-DR interaction modeled using the ETHOS framework assuming a constant scattering rate between the two components. Most importantly, we find that 21 cm observations can improve the sensitivity to the DM-DR interaction rate by up to four order of magnitude compared to Planck and SO. Conversely, in the limit of low interaction rate (which asymptotically matches Neff), CMB data dominates the constraining power, but the inclusion of HERA data can provide a ∼ 20% improvement in sensitivity over CMB data alone. Moreover, we find that HERA observations will be able to probe a region of the DM-DR interaction parameter space which is promising to explain the weak lensing amplitude `S8' tension. Our results demonstrate the complementarity of 21 cm and CMB data in exploring dark sector interactions.
{"title":"Probing dark relativistic species and their interactions with dark matter through CMB and 21 cm surveys","authors":"Hugo Plombat, Théo Simon, Jordan Flitter and Vivian Poulin","doi":"10.1088/1475-7516/2025/01/071","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/071","url":null,"abstract":"We investigate the sensitivity of the 21 cm power spectrum from cosmic dawn and the epoch of reionization to models of free-streaming dark radiation (parameterized through Neff) and interacting dark radiation-dark matter models (DM-DR). The latter models have gained attention for their potential in addressing recent cosmological tensions and structure formation challenges. We perform a Fisher matrix analysis under different assumptions regarding the astrophysical modeling, and forecast the sensitivity of HERA observations, combined with CMB data from Planck and the Simons Observatory (SO), to Neff and DM-DR interaction modeled using the ETHOS framework assuming a constant scattering rate between the two components. Most importantly, we find that 21 cm observations can improve the sensitivity to the DM-DR interaction rate by up to four order of magnitude compared to Planck and SO. Conversely, in the limit of low interaction rate (which asymptotically matches Neff), CMB data dominates the constraining power, but the inclusion of HERA data can provide a ∼ 20% improvement in sensitivity over CMB data alone. Moreover, we find that HERA observations will be able to probe a region of the DM-DR interaction parameter space which is promising to explain the weak lensing amplitude `S8' tension. Our results demonstrate the complementarity of 21 cm and CMB data in exploring dark sector interactions.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"2 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986125","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/076
Xavier Pritchard and Christian T. Byrnes
Phase transitions in the early universe lead to a reduction in the equation of state of the primordial plasma. This exponentially enhances the formation rate of primordial black holes. However, this sensitivity to the equation of state is the same that primordial black hole abundances show to the primordial curvature power spectrum amplitude. In this paper, we investigate peaked power spectra and show the challenges associated with motivating populations of primordial black holes with standard model enhancements. The parametrisation of different power spectra plays an important role in this discussion. The allowed parameter space consistent with a large QCD phase transition impact on the primordial black hole abundance differs greatly. This is particularly evident for broader spectra. We also show that, in our framework, the electroweak phase transition cannot significantly affect the overall abundance.
{"title":"Constraining the impact of standard model phase transitions on primordial black holes","authors":"Xavier Pritchard and Christian T. Byrnes","doi":"10.1088/1475-7516/2025/01/076","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/076","url":null,"abstract":"Phase transitions in the early universe lead to a reduction in the equation of state of the primordial plasma. This exponentially enhances the formation rate of primordial black holes. However, this sensitivity to the equation of state is the same that primordial black hole abundances show to the primordial curvature power spectrum amplitude. In this paper, we investigate peaked power spectra and show the challenges associated with motivating populations of primordial black holes with standard model enhancements. The parametrisation of different power spectra plays an important role in this discussion. The allowed parameter space consistent with a large QCD phase transition impact on the primordial black hole abundance differs greatly. This is particularly evident for broader spectra. We also show that, in our framework, the electroweak phase transition cannot significantly affect the overall abundance.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"104 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986344","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/074
Federico Greco and Marco Peloso
The original model of axion natural inflation produces a tensor-to-scalar ratio above the experimental limit. Aligned axion inflation admits inflationary trajectories that originate near a saddle point of the two-field potential, and terminate due to the instability of the orthogonal direction. The phenomenology of these solutions is within the current constraints, and a range of parameters will be probed by the next stage CMB experiments. We provide the analytic solution for these trajectories and very compact analytic expressions for the associated phenomenology. For parameters leading to the observed value for the scalar spectral tilt the extension of the inflationary trajectory is sub-Planckian. However, one eigenvalue of the axion kinetic matrix (in the basis that diagonalizes the potential) is trans-Planckian. Finally, we discuss the post-inflationary evolution after the instability. In some cases, the fields reach a second inflationary valley, connected to a minimum. Multiple stages of inflation might be a more general occurrence in multiple-field inflationary models with trajectories starting next to critical points.
{"title":"Analytic results in aligned axion inflation","authors":"Federico Greco and Marco Peloso","doi":"10.1088/1475-7516/2025/01/074","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/074","url":null,"abstract":"The original model of axion natural inflation produces a tensor-to-scalar ratio above the experimental limit. Aligned axion inflation admits inflationary trajectories that originate near a saddle point of the two-field potential, and terminate due to the instability of the orthogonal direction. The phenomenology of these solutions is within the current constraints, and a range of parameters will be probed by the next stage CMB experiments. We provide the analytic solution for these trajectories and very compact analytic expressions for the associated phenomenology. For parameters leading to the observed value for the scalar spectral tilt the extension of the inflationary trajectory is sub-Planckian. However, one eigenvalue of the axion kinetic matrix (in the basis that diagonalizes the potential) is trans-Planckian. Finally, we discuss the post-inflationary evolution after the instability. In some cases, the fields reach a second inflationary valley, connected to a minimum. Multiple stages of inflation might be a more general occurrence in multiple-field inflationary models with trajectories starting next to critical points.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"24 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986131","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/069
Kunal Pal, Kuntal Pal and Tapobrata Sarkar
Using the Israel-Darmois junction conditions, we obtain a class of regular dynamical interiors to the recently proposed black-bounce spacetimes which regularises the Schwarzschild singularity by introducing a regularisation parameter. We show that a regularised Friedmann-Lemaitre-Robertson-Walker like interior geometry can not be matched smoothly with the exterior black-bounce spacetime through a timelike hypersurface, as there always exists a thin shell of non-zero energy-momentum tensor at the matching hypersurface. We obtain the expressions for the energy density and pressure corresponding to the thin-shell surface energy-momentum tensor in terms of the regularisation parameter and derive an evolution equation for the scale factor of the interior geometry by imposing physical conditions on these components. We also discuss the formation of the event horizon inside the interior in the case when the initial conditions are such that the situation describes a collapsing matter cloud. We elaborate upon the physical implications of these results.
{"title":"Dynamical interiors of black-bounce spacetimes","authors":"Kunal Pal, Kuntal Pal and Tapobrata Sarkar","doi":"10.1088/1475-7516/2025/01/069","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/069","url":null,"abstract":"Using the Israel-Darmois junction conditions, we obtain a class of regular dynamical interiors to the recently proposed black-bounce spacetimes which regularises the Schwarzschild singularity by introducing a regularisation parameter. We show that a regularised Friedmann-Lemaitre-Robertson-Walker like interior geometry can not be matched smoothly with the exterior black-bounce spacetime through a timelike hypersurface, as there always exists a thin shell of non-zero energy-momentum tensor at the matching hypersurface. We obtain the expressions for the energy density and pressure corresponding to the thin-shell surface energy-momentum tensor in terms of the regularisation parameter and derive an evolution equation for the scale factor of the interior geometry by imposing physical conditions on these components. We also discuss the formation of the event horizon inside the interior in the case when the initial conditions are such that the situation describes a collapsing matter cloud. We elaborate upon the physical implications of these results.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"103 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986126","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/073
Giulia Ventagli and Ippocratis D. Saltas
We present a pipeline to infer the equation of state of neutron stars from observations based on deep neural networks. In particular, using the standard (deterministic), as well as Bayesian (probabilistic) deep networks, we explore how one can infer the interior speed of sound of the star given a set of mock observations of total stellar mass, stellar radius and tidal deformability. We discuss in detail the construction of our simulated dataset of stellar observables starting from the solution of the gravitational equations, as well as the relevant architectures for the deep networks, along with their performance and accuracy. We further explain how our pipeline is capable to detect a possible QCD phase transition in the stellar core. Our results show that deep networks offer a promising tool towards solving the inverse problem of neutron stars, and the accurate inference of their interior from future stellar observations.
{"title":"Deep learning inference of the neutron star equation of state","authors":"Giulia Ventagli and Ippocratis D. Saltas","doi":"10.1088/1475-7516/2025/01/073","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/073","url":null,"abstract":"We present a pipeline to infer the equation of state of neutron stars from observations based on deep neural networks. In particular, using the standard (deterministic), as well as Bayesian (probabilistic) deep networks, we explore how one can infer the interior speed of sound of the star given a set of mock observations of total stellar mass, stellar radius and tidal deformability. We discuss in detail the construction of our simulated dataset of stellar observables starting from the solution of the gravitational equations, as well as the relevant architectures for the deep networks, along with their performance and accuracy. We further explain how our pipeline is capable to detect a possible QCD phase transition in the stellar core. Our results show that deep networks offer a promising tool towards solving the inverse problem of neutron stars, and the accurate inference of their interior from future stellar observations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"8 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986129","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/070
Chandrachud B.V. Dash and Tapomoy Guha Sarkar
We propose an anisotropy quantifier of the H i 21-cm signal traditionally used to clock the astrophysics of the reionization era as a post-reionization dark energy diagnostic. We find that the anisotropy probe can be measured at SNR ∼ 10 in both auto-correlation and in cross-correlation with the Ly-α forest over a wide z and k-range. We propose to use the BAO signature on the anisotropy signal to measure ( H(z), DA(z)). Subsequently, we put constraints on a dark energy model involving a negative cosmological constant on top of a quintessence scalar field and find that such a model is consistent with futuristic observations.
{"title":"Probing dark energy using anisotropies in the clustering of post-EoR H i distribution","authors":"Chandrachud B.V. Dash and Tapomoy Guha Sarkar","doi":"10.1088/1475-7516/2025/01/070","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/070","url":null,"abstract":"We propose an anisotropy quantifier of the H i 21-cm signal traditionally used to clock the astrophysics of the reionization era as a post-reionization dark energy diagnostic. We find that the anisotropy probe can be measured at SNR ∼ 10 in both auto-correlation and in cross-correlation with the Ly-α forest over a wide z and k-range. We propose to use the BAO signature on the anisotropy signal to measure ( H(z), DA(z)). Subsequently, we put constraints on a dark energy model involving a negative cosmological constant on top of a quintessence scalar field and find that such a model is consistent with futuristic observations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"27 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986124","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/072
A.A. Araújo Filho
We explore the gravitational properties of a nonlinear electromagnetic extension of an AdS Reissner-Nordström black hole. Our study begins with an analysis of the metric function and horizon structure, followed by calculations of the Ricci and Kretschmann scalars and an evaluation of the non-vanishing Christoffel symbols. These calculations allow us to examine geodesics and their influence on the photon sphere and shadow formation. In the thermodynamic framework, we evaluate essential quantities, including the Hawking temperature, entropy, heat capacity, Gibbs free energy, and Hawking radiation emission. We further investigate black hole evaporation by estimating the evaporation timescale as the black hole approaches its final state. Additionally, quasinormal modes for scalar and vector perturbations are computed using the WKB approximation to characterize oscillatory behavior of the system. Finally, a time-domain analysis is provided in order to examine the evolution of these perturbations.
{"title":"Remarks on a nonlinear electromagnetic extension in AdS Reissner-Nordström spacetime","authors":"A.A. Araújo Filho","doi":"10.1088/1475-7516/2025/01/072","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/072","url":null,"abstract":"We explore the gravitational properties of a nonlinear electromagnetic extension of an AdS Reissner-Nordström black hole. Our study begins with an analysis of the metric function and horizon structure, followed by calculations of the Ricci and Kretschmann scalars and an evaluation of the non-vanishing Christoffel symbols. These calculations allow us to examine geodesics and their influence on the photon sphere and shadow formation. In the thermodynamic framework, we evaluate essential quantities, including the Hawking temperature, entropy, heat capacity, Gibbs free energy, and Hawking radiation emission. We further investigate black hole evaporation by estimating the evaporation timescale as the black hole approaches its final state. Additionally, quasinormal modes for scalar and vector perturbations are computed using the WKB approximation to characterize oscillatory behavior of the system. Finally, a time-domain analysis is provided in order to examine the evolution of these perturbations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"127 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986128","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/068
Zhi Shen, Jun Zhang, Cong Liu, Hekun Li, Haoran Wang, Zhenjie Liu and Jiarui Sun
Tele-correlation refers to the correlation of galaxy shapes with large angular separations (e.g., > 100 degrees). Since there are no astrophysical reasons causing such a correlation on cosmological scales, any detected tele-correlation could disclose systematic effects in shear-shear correlation measurement. If the shear estimators are measured on single exposures, we show that the field distortion (FD) signal associated with the galaxy position on the CCD can be retained and used in tele-correlation to help us directly calibrate the multiplicative and additive biases in shear-shear correlations. We use the DECaLS shear catalog produced by the Fourier_Quad pipeline to demonstrate this idea. To our surprise, we find that significant multiplicative biases can arise (up to more than 10%) due to redshift binning of the galaxies. Correction for this bias leads to about 1σ increase of the best-fit value of S8 from 0.760+0.015-0.017 to 0.777+0.016-0.019 in our tomography study.
{"title":"Tele-correlation: calibrating shear-shear correlation with real data","authors":"Zhi Shen, Jun Zhang, Cong Liu, Hekun Li, Haoran Wang, Zhenjie Liu and Jiarui Sun","doi":"10.1088/1475-7516/2025/01/068","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/068","url":null,"abstract":"Tele-correlation refers to the correlation of galaxy shapes with large angular separations (e.g., > 100 degrees). Since there are no astrophysical reasons causing such a correlation on cosmological scales, any detected tele-correlation could disclose systematic effects in shear-shear correlation measurement. If the shear estimators are measured on single exposures, we show that the field distortion (FD) signal associated with the galaxy position on the CCD can be retained and used in tele-correlation to help us directly calibrate the multiplicative and additive biases in shear-shear correlations. We use the DECaLS shear catalog produced by the Fourier_Quad pipeline to demonstrate this idea. To our surprise, we find that significant multiplicative biases can arise (up to more than 10%) due to redshift binning of the galaxies. Correction for this bias leads to about 1σ increase of the best-fit value of S8 from 0.760+0.015-0.017 to 0.777+0.016-0.019 in our tomography study.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986123","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}
Pub Date : 2025-01-16DOI: 10.1088/1475-7516/2025/01/075
A. Pugno, A. Eggemeier, C. Porciani and J. Kuruvilla
Redshift-space distortions (RSDs) present a significant challenge in building models for the three-point correlation function (3PCF). We compare two possible lines of attack: the streaming model and standard perturbation theory (SPT). The two approaches differ in their treatment of the non-linear mapping from real to redshift space: SPT expands this mapping perturbatively, while the streaming model retains its non-linear form but relies on simplifying assumptions about the probability density function (PDF) of line-of-sight velocity differences between pairs or triplets of tracers. To assess the quality of the predictions and the validity of the assumptions of these models, we measure the monopole of the matter 3PCF and the first two moments of the pair- and triplewise velocity PDF from a suite of N-body simulations. We also evaluate the large-scale limit of the streaming model and determine under which conditions it aligns to SPT. On scales larger than 10 h-1 Mpc, we find that the streaming model for the 3PCF monopole is dominated by the first two velocity moments, making the exact shape of the PDF irrelevant. This model can match the accuracy of a Stage-IV galaxy survey, if the velocity moments are measured directly from the simulations. However, replacing the measurements with perturbative expressions to leading order generates large errors already on scales of 60–70 h-1 Mpc. This is the primary drawback of the streaming model. On the other hand, the SPT model for the 3PCF cannot account for the significant velocity dispersion that is present at all scales, and consequently provides predictions with limited accuracy. We demonstrate that this issue can be approximately addressed by isolating the large-scale limit of the dispersion, which leads to typical Fingers-of-God damping functions. Overall, the SPT model with a damping function provides the best compromise in terms of accuracy and computing time.
{"title":"The streaming model for the three-point correlation function and its connection to standard perturbation theory","authors":"A. Pugno, A. Eggemeier, C. Porciani and J. Kuruvilla","doi":"10.1088/1475-7516/2025/01/075","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/075","url":null,"abstract":"Redshift-space distortions (RSDs) present a significant challenge in building models for the three-point correlation function (3PCF). We compare two possible lines of attack: the streaming model and standard perturbation theory (SPT). The two approaches differ in their treatment of the non-linear mapping from real to redshift space: SPT expands this mapping perturbatively, while the streaming model retains its non-linear form but relies on simplifying assumptions about the probability density function (PDF) of line-of-sight velocity differences between pairs or triplets of tracers. To assess the quality of the predictions and the validity of the assumptions of these models, we measure the monopole of the matter 3PCF and the first two moments of the pair- and triplewise velocity PDF from a suite of N-body simulations. We also evaluate the large-scale limit of the streaming model and determine under which conditions it aligns to SPT. On scales larger than 10 h-1 Mpc, we find that the streaming model for the 3PCF monopole is dominated by the first two velocity moments, making the exact shape of the PDF irrelevant. This model can match the accuracy of a Stage-IV galaxy survey, if the velocity moments are measured directly from the simulations. However, replacing the measurements with perturbative expressions to leading order generates large errors already on scales of 60–70 h-1 Mpc. This is the primary drawback of the streaming model. On the other hand, the SPT model for the 3PCF cannot account for the significant velocity dispersion that is present at all scales, and consequently provides predictions with limited accuracy. We demonstrate that this issue can be approximately addressed by isolating the large-scale limit of the dispersion, which leads to typical Fingers-of-God damping functions. Overall, the SPT model with a damping function provides the best compromise in terms of accuracy and computing time.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"77 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986130","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}
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