Pub Date : 2025-04-23DOI: 10.1088/1475-7516/2025/04/072
Luca Di Luzio, Sebastian Hoof, Coenraad Marinissen and Vaisakh Plakkot
We extend the catalogue of “phenomenologically preferred” hadronic axion models to include heavy fermion representations associated with higher-dimensional decay operators. The latter have recently been shown to self-consistently trigger a period of early matter domination, making the underlying axion models cosmologically viable. After identifying all possible representations up to decay operator dimension d ≤ 9, we update the hadronic axion band for the axion-photon coupling. The central regions of the axion band are similar to those found previously and approximately independent of the axion decay constant fa, suggesting that they are robust predictions and targets for future axion searches. Moreover, we find that d = 6 and d = 7 operators can lead to two new viable “model islands” around fa ∼ 1012 GeV and fa ∼ 1014 GeV, i.e., beyond the standard post-inflationary mass region.
{"title":"Catalogues of cosmologically self-consistent hadronic QCD axion models","authors":"Luca Di Luzio, Sebastian Hoof, Coenraad Marinissen and Vaisakh Plakkot","doi":"10.1088/1475-7516/2025/04/072","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/072","url":null,"abstract":"We extend the catalogue of “phenomenologically preferred” hadronic axion models to include heavy fermion representations associated with higher-dimensional decay operators. The latter have recently been shown to self-consistently trigger a period of early matter domination, making the underlying axion models cosmologically viable. After identifying all possible representations up to decay operator dimension d ≤ 9, we update the hadronic axion band for the axion-photon coupling. The central regions of the axion band are similar to those found previously and approximately independent of the axion decay constant fa, suggesting that they are robust predictions and targets for future axion searches. Moreover, we find that d = 6 and d = 7 operators can lead to two new viable “model islands” around fa ∼ 1012 GeV and fa ∼ 1014 GeV, i.e., beyond the standard post-inflationary mass region.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"32 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866968","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/071
Nicolas R. Bertini
A fundamental element of scale-dependent gravity is the scale-setting procedure. We present a new covariant expression to set the scale that arises when examining the field equations. Considering the renormalization group equations and imposing energy-momentum tensor conservation, we arrive at two models of running of the gravitational and cosmological constants. In the cosmological setting, we found that in one model the Big Bang singularity is avoided, while in the other the Hubble tension can be alleviated. At the level of cosmological perturbations, we derived the basic solutions and qualitatively discussed the impacts of this scenario on structure formation.
{"title":"Scale-dependent gravity and covariant scale-setting","authors":"Nicolas R. Bertini","doi":"10.1088/1475-7516/2025/04/071","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/071","url":null,"abstract":"A fundamental element of scale-dependent gravity is the scale-setting procedure. We present a new covariant expression to set the scale that arises when examining the field equations. Considering the renormalization group equations and imposing energy-momentum tensor conservation, we arrive at two models of running of the gravitational and cosmological constants. In the cosmological setting, we found that in one model the Big Bang singularity is avoided, while in the other the Hubble tension can be alleviated. At the level of cosmological perturbations, we derived the basic solutions and qualitatively discussed the impacts of this scenario on structure formation.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866967","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/065
Muhammad Ali Raza, Francisco Tello-Ortiz, M. Zubair, Y. Gómez-Leyton
In this work, we consider a static wormhole in Bopp-Podolsky electrodynamics and convert it into its rotating counterpart by reducing it into Morris-Thorne form. We further study the null geodesics and effective potential along with the shadows for inner and outer unstable orbits for specific choices of parameters. It is found that for some cases smooth shadow curves are formed, and for a few cases the shadows formed are cuspy. All parameters have a significant impact on the shadows except for the parameter b when either a or Q are kept small. We also analyze the gravitational lensing in the strong regime, considering that the observer and the source are on opposite sides of the throat. For this situation, we explore in detail the behavior of the deflection angle, Einstein rings and lensing observables.
{"title":"Some optical properties of rotating wormhole in Bopp-Podolsky electrodynamics","authors":"Muhammad Ali Raza, Francisco Tello-Ortiz, M. Zubair, Y. Gómez-Leyton","doi":"10.1088/1475-7516/2025/04/065","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/065","url":null,"abstract":"In this work, we consider a static wormhole in Bopp-Podolsky electrodynamics and convert it into its rotating counterpart by reducing it into Morris-Thorne form. We further study the null geodesics and effective potential along with the shadows for inner and outer unstable orbits for specific choices of parameters. It is found that for some cases smooth shadow curves are formed, and for a few cases the shadows formed are cuspy. All parameters have a significant impact on the shadows except for the parameter <italic toggle=\"yes\">b</italic> when either <italic toggle=\"yes\">a</italic> or <italic toggle=\"yes\">Q</italic> are kept small. We also analyze the gravitational lensing in the strong regime, considering that the observer and the source are on opposite sides of the throat. For this situation, we explore in detail the behavior of the deflection angle, Einstein rings and lensing observables.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"50 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863013","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/067
Jan Tristram Acuña, Kuan-Yen Chou and Po-Yan Tseng
Axions are hypothetical pseudoscalar particles that have been regarded as promising dark matter (DM) candidates. On the other hand, extended compact objects such as axion stars, which are supported by gravity and axion self interactions, may have also been formed in the early Universe and comprise part of DM. In this work, we consider the lensing of electromagnetic signals from distant sources by axion stars, as a way to constrain the properties of axion stars and fundamental axion parameters. Accounting for the effect of the finite size of the axion star, we study the lensing effect induced by gravity, and by axion-photon interactions. The latter effect is frequency dependent, and is relevant in the low frequency band, which motivates the use of fast radio burst (FRB) signals as a probe. We calculate the predicted number of lensed FRB events by specifying the fundamental axion parameters, axion star radial profile, fraction of DM residing in axion stars, and imposing lensing criteria based on the flux ratio and time delay between the brightest images from lensing. Assuming an optimistic case of 104 observed FRB events, and a timing resolution of 1 μs, the lack of observed FRB lensing events in CHIME allows us to probe axion stars with mass ≳ 10-2M⊙, corresponding to axion masses ≲ 10-10 eV and for negligible axion-photon couplings. Even lighter axion stars up to ∼ 10-3M⊙ can be probed, assuming axion-photon couplings of at least 10-6 GeV-1. Our results indicate that while FRB lensing by axion stars lead to sensitivities that are competitive with conventional microlensing searches operating in the optical band, it remains a challenge to probe axion-photon induced lensing effects.
{"title":"Constraints on extended axion structures from the lensing of fast radio bursts","authors":"Jan Tristram Acuña, Kuan-Yen Chou and Po-Yan Tseng","doi":"10.1088/1475-7516/2025/04/067","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/067","url":null,"abstract":"Axions are hypothetical pseudoscalar particles that have been regarded as promising dark matter (DM) candidates. On the other hand, extended compact objects such as axion stars, which are supported by gravity and axion self interactions, may have also been formed in the early Universe and comprise part of DM. In this work, we consider the lensing of electromagnetic signals from distant sources by axion stars, as a way to constrain the properties of axion stars and fundamental axion parameters. Accounting for the effect of the finite size of the axion star, we study the lensing effect induced by gravity, and by axion-photon interactions. The latter effect is frequency dependent, and is relevant in the low frequency band, which motivates the use of fast radio burst (FRB) signals as a probe. We calculate the predicted number of lensed FRB events by specifying the fundamental axion parameters, axion star radial profile, fraction of DM residing in axion stars, and imposing lensing criteria based on the flux ratio and time delay between the brightest images from lensing. Assuming an optimistic case of 104 observed FRB events, and a timing resolution of 1 μs, the lack of observed FRB lensing events in CHIME allows us to probe axion stars with mass ≳ 10-2M⊙, corresponding to axion masses ≲ 10-10 eV and for negligible axion-photon couplings. Even lighter axion stars up to ∼ 10-3M⊙ can be probed, assuming axion-photon couplings of at least 10-6 GeV-1. Our results indicate that while FRB lensing by axion stars lead to sensitivities that are competitive with conventional microlensing searches operating in the optical band, it remains a challenge to probe axion-photon induced lensing effects.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"6 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866811","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/066
Nassim Bozorgnia, Muping Chen, Graciela B. Gelmini, Alvine C. Kamaha and Yongheng Xu
Xenon and argon are the two noble gases used in tonne scale dark matter direct detection experiments. We compare the detection capability of both target elements for interactions due to a pseudoscalar mediator including loop-level contributions to the cross section. At tree-level this type of interaction depends on the nuclear spin and would thus not be detectable in argon-based detectors, since Ar has spin zero. However, at the loop-level the same interaction yields spin-independent contributions that would be detectable in an argon target and are not negligible with respect to the tree-level interactions in xenon, because these are momentum suppressed. In fact, the loop-level contributions are also important for xenon-based experiments at low recoil energies, which could change their discovery reach for this interaction.
{"title":"Spin-dependent dark matter interactions at loop-level in Ar and Xe","authors":"Nassim Bozorgnia, Muping Chen, Graciela B. Gelmini, Alvine C. Kamaha and Yongheng Xu","doi":"10.1088/1475-7516/2025/04/066","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/066","url":null,"abstract":"Xenon and argon are the two noble gases used in tonne scale dark matter direct detection experiments. We compare the detection capability of both target elements for interactions due to a pseudoscalar mediator including loop-level contributions to the cross section. At tree-level this type of interaction depends on the nuclear spin and would thus not be detectable in argon-based detectors, since Ar has spin zero. However, at the loop-level the same interaction yields spin-independent contributions that would be detectable in an argon target and are not negligible with respect to the tree-level interactions in xenon, because these are momentum suppressed. In fact, the loop-level contributions are also important for xenon-based experiments at low recoil energies, which could change their discovery reach for this interaction.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"48 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866810","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/073
Joseph H.P. Jackson, Hooshyar Assadullahi, Andrew D. Gow, Kazuya Koyama, Vincent Vennin and David Wands
We simulate the distribution of very rare, large excursions in the primordial density field produced in models of inflation in the very early universe which include a strong enhancement of the power spectrum. The stochastic δ𝒩 formalism is used to identify the probability distribution for the primordial curvature perturbation with the first-passage-time distribution, P(δ𝒩), and we compare our stochastic results with those obtained in the classical δ𝒩 approach. We extend the PyFPT numerical code to simulate the full 2D phase space, and apply importance sampling which allows very rare fluctuations to be simulated in 𝒪(10) minutes on a single CPU, where previous direct simulations required supercomputers. We demonstrate that the stochastic noise due to quantum fluctuations after a sudden transition to ultra-slow roll can be accurately modelled using an analytical Bessel-function ansatz to identify the homogeneous growing mode. The stochastic noise found in this way is a function of the field value only. This enables us to coarse grain the inflation field at the Hubble scale and include non-linear, stochastic evolution on all super-Hubble length scales.
{"title":"Stochastic inflation beyond slow roll: noise modelling and importance sampling","authors":"Joseph H.P. Jackson, Hooshyar Assadullahi, Andrew D. Gow, Kazuya Koyama, Vincent Vennin and David Wands","doi":"10.1088/1475-7516/2025/04/073","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/073","url":null,"abstract":"We simulate the distribution of very rare, large excursions in the primordial density field produced in models of inflation in the very early universe which include a strong enhancement of the power spectrum. The stochastic δ𝒩 formalism is used to identify the probability distribution for the primordial curvature perturbation with the first-passage-time distribution, P(δ𝒩), and we compare our stochastic results with those obtained in the classical δ𝒩 approach. We extend the PyFPT numerical code to simulate the full 2D phase space, and apply importance sampling which allows very rare fluctuations to be simulated in 𝒪(10) minutes on a single CPU, where previous direct simulations required supercomputers. We demonstrate that the stochastic noise due to quantum fluctuations after a sudden transition to ultra-slow roll can be accurately modelled using an analytical Bessel-function ansatz to identify the homogeneous growing mode. The stochastic noise found in this way is a function of the field value only. This enables us to coarse grain the inflation field at the Hubble scale and include non-linear, stochastic evolution on all super-Hubble length scales.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"70 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866969","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/070
A. Aires, N. Kokron, R. Rosenfeld, F. Andrade-Oliveira and V. Miranda
Stage-IV galaxy surveys will measure correlations at small cosmological scales with high signal-to-noise ratio. One of the main challenges of extracting information from small scales is devising accurate models, as well as characterizing the theoretical uncertainties associated with any given model. In this work, we explore the mitigation of theoretical uncertainty due to nonlinear galaxy bias in the context of photometric 2×2-point analyses. We consider linear galaxy bias as the fiducial model and derive the contribution to the covariance matrix induced by neglected higher-order bias. We construct a covariance matrix for the theoretical error in galaxy clustering and galaxy-galaxy lensing using simulation-based relations that connect higher-order parameters to linear bias. To test this mitigation model, we apply the modified likelihood to 2×2-point analyses based on two sets of mock data vectors: (1) simulated data vectors, constructed from those same relations between bias parameters, and (2) data vectors based on the AbacusSummit simulation suite. We then compare the performance of the theoretical-error approach to the commonly employed scale cuts methodology. We find most theoretical-error configurations yield results equivalent to the scale cuts in terms of precision and accuracy, and in some cases, especially with the first data set, they produce significantly stronger bounds on cosmological parameters. These results are independent of the maximum scale kmax in the analysis with theoretical error. We notice the relative performance of the theoretical-error approach depends mostly on the choice of the covariance-matrix diagonal. The scenarios where linear bias supplemented by theoretical error is unable to recover unbiased cosmology, which are mainly observed with the second data set, are connected to inadequate modeling of the gg-gκ covariance of theoretical error. This form of cross-probe covariance has not been considered in previous works. We additionally highlight a sensitivity of the construction to off-diagonal correlations of theoretical error. In view of its removing the ambiguity in the choice of kmax, as well as the possibility of attaining higher precision than the usual scale cuts, we consider this method to be promising for analyses of LSS in upcoming photometric galaxy surveys.
{"title":"Mitigation of nonlinear galaxy bias with a theoretical-error likelihood","authors":"A. Aires, N. Kokron, R. Rosenfeld, F. Andrade-Oliveira and V. Miranda","doi":"10.1088/1475-7516/2025/04/070","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/070","url":null,"abstract":"Stage-IV galaxy surveys will measure correlations at small cosmological scales with high signal-to-noise ratio. One of the main challenges of extracting information from small scales is devising accurate models, as well as characterizing the theoretical uncertainties associated with any given model. In this work, we explore the mitigation of theoretical uncertainty due to nonlinear galaxy bias in the context of photometric 2×2-point analyses. We consider linear galaxy bias as the fiducial model and derive the contribution to the covariance matrix induced by neglected higher-order bias. We construct a covariance matrix for the theoretical error in galaxy clustering and galaxy-galaxy lensing using simulation-based relations that connect higher-order parameters to linear bias. To test this mitigation model, we apply the modified likelihood to 2×2-point analyses based on two sets of mock data vectors: (1) simulated data vectors, constructed from those same relations between bias parameters, and (2) data vectors based on the AbacusSummit simulation suite. We then compare the performance of the theoretical-error approach to the commonly employed scale cuts methodology. We find most theoretical-error configurations yield results equivalent to the scale cuts in terms of precision and accuracy, and in some cases, especially with the first data set, they produce significantly stronger bounds on cosmological parameters. These results are independent of the maximum scale kmax in the analysis with theoretical error. We notice the relative performance of the theoretical-error approach depends mostly on the choice of the covariance-matrix diagonal. The scenarios where linear bias supplemented by theoretical error is unable to recover unbiased cosmology, which are mainly observed with the second data set, are connected to inadequate modeling of the gg-gκ covariance of theoretical error. This form of cross-probe covariance has not been considered in previous works. We additionally highlight a sensitivity of the construction to off-diagonal correlations of theoretical error. In view of its removing the ambiguity in the choice of kmax, as well as the possibility of attaining higher precision than the usual scale cuts, we consider this method to be promising for analyses of LSS in upcoming photometric galaxy surveys.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"19 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866814","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/069
Xing-Yu Yang, Tan Chen and Rong-Gen Cai
Gravitational waves (GWs) offer a new observational window into the universe, providing insights into compact objects and cosmic structures. Gravitational lensing, commonly studied in electromagnetic waves, also affects GWs, introducing magnification, time delays, and multiple images. While existing studies focus on static lenses, many astrophysical lenses are dynamic, with time-varying mass distributions such as moving stars or orbiting binaries. We develop a general theoretical framework to describe non-static lenses and demonstrate how they modulate GW signals, inducing unique time-varying amplitude modulations and spectral broadening. By examining uniformly moving and orbiting binary lenses, we show that these modulations provide new observational signatures, enhancing our understanding of lensing objects and the dynamics of the universe. Our findings have important implications for GW astronomy, offering novel ways to probe lens dynamics and improve the interpretations of GW signals.
{"title":"Modulations of gravitational waves due to non-static gravitational lenses","authors":"Xing-Yu Yang, Tan Chen and Rong-Gen Cai","doi":"10.1088/1475-7516/2025/04/069","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/069","url":null,"abstract":"Gravitational waves (GWs) offer a new observational window into the universe, providing insights into compact objects and cosmic structures. Gravitational lensing, commonly studied in electromagnetic waves, also affects GWs, introducing magnification, time delays, and multiple images. While existing studies focus on static lenses, many astrophysical lenses are dynamic, with time-varying mass distributions such as moving stars or orbiting binaries. We develop a general theoretical framework to describe non-static lenses and demonstrate how they modulate GW signals, inducing unique time-varying amplitude modulations and spectral broadening. By examining uniformly moving and orbiting binary lenses, we show that these modulations provide new observational signatures, enhancing our understanding of lensing objects and the dynamics of the universe. Our findings have important implications for GW astronomy, offering novel ways to probe lens dynamics and improve the interpretations of GW signals.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"2 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866813","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 : 2025-04-23DOI: 10.1088/1475-7516/2025/04/068
Bo Wang, Dong-Ze He, Ling-Feng Wang, Hai-Li Li and Yi Zhang
We explore the constraints on cosmological parameters in interacting dark energy (IDE) models with energy transfer rates Q = βH ρde and Q = βH ρc, using simulated gravitational-wave (GW) bright sirens data from pulsar timing array (PTA) and Planck 2018 cosmic microwave background (CMB) data. By incorporating the mock PTA data from future observations in the FAST/SKA era, we demonstrate significant improvements on the constraint precision of key cosmological parameters such as the Hubble constant H0, matter density Ωm, and the coupling parameter β. In the IDE model with Q = βH ρde, PTA data could provide tighter constraints on these parameters than CMB data, particularly due to the high sensitivity of GW standard sirens in probing the late universe. Combination of PTA and CMB data could lead to the constraint improvements of 37.4% for H0, 37.4% for Ωm, and 36.1% for β, compared to the case using CMB data alone. In contrast, for the IDE model with Q = βH ρc, the CMB data alone could provide tighter constraints on ρ compared with PTA data, due to the stronger effect of CMB in the early universe. Combination of PTA and CMB data still yields constraint improvements of 17.6% for H0, 24.3% for Ωm and 17.4% for β compared to the case using CMB data alone. With the increase of the number of millisecond pulsars (MSPs), the constraints on all parameters for both IDE models can be further enhanced. Our results highlight the potential of future PTA observations to significantly improve the cosmological parameter estimation in IDE models, offering crucial insights into the nature of dark energy and the interaction between dark sectors.
{"title":"Prospects for constraining interacting dark energy cosmology with gravitational-wave bright sirens detected by future FAST/SKA-era pulsar timing arrays","authors":"Bo Wang, Dong-Ze He, Ling-Feng Wang, Hai-Li Li and Yi Zhang","doi":"10.1088/1475-7516/2025/04/068","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/068","url":null,"abstract":"We explore the constraints on cosmological parameters in interacting dark energy (IDE) models with energy transfer rates Q = βH ρde and Q = βH ρc, using simulated gravitational-wave (GW) bright sirens data from pulsar timing array (PTA) and Planck 2018 cosmic microwave background (CMB) data. By incorporating the mock PTA data from future observations in the FAST/SKA era, we demonstrate significant improvements on the constraint precision of key cosmological parameters such as the Hubble constant H0, matter density Ωm, and the coupling parameter β. In the IDE model with Q = βH ρde, PTA data could provide tighter constraints on these parameters than CMB data, particularly due to the high sensitivity of GW standard sirens in probing the late universe. Combination of PTA and CMB data could lead to the constraint improvements of 37.4% for H0, 37.4% for Ωm, and 36.1% for β, compared to the case using CMB data alone. In contrast, for the IDE model with Q = βH ρc, the CMB data alone could provide tighter constraints on ρ compared with PTA data, due to the stronger effect of CMB in the early universe. Combination of PTA and CMB data still yields constraint improvements of 17.6% for H0, 24.3% for Ωm and 17.4% for β compared to the case using CMB data alone. With the increase of the number of millisecond pulsars (MSPs), the constraints on all parameters for both IDE models can be further enhanced. Our results highlight the potential of future PTA observations to significantly improve the cosmological parameter estimation in IDE models, offering crucial insights into the nature of dark energy and the interaction between dark sectors.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"17 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866812","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 : 2025-04-22DOI: 10.1088/1475-7516/2025/04/063
Hiroaki Nakajima, Ya Guo, Wenbin Lin
We study the wave equations with the various spins on the background of the Kerr metric deformed by a function of the radial coordinate, on which we have studied the gravitational-wave equations previously. We obtain the unified expression of the Teukolsky-like master equations and the corresponding radial equations with various spins. We find that taking the separable gauge introduced in previous study simplifies the unified form. We also discuss the structure of the radial equation as an ordinary differential equation, such as the existence of the regular and the irregular singularities of the equation and the behavior of the solution around each singularity.
{"title":"Teukolsky-like equations with various spins in a deformed Kerr spacetime","authors":"Hiroaki Nakajima, Ya Guo, Wenbin Lin","doi":"10.1088/1475-7516/2025/04/063","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/063","url":null,"abstract":"We study the wave equations with the various spins on the background of the Kerr metric deformed by a function of the radial coordinate, on which we have studied the gravitational-wave equations previously. We obtain the unified expression of the Teukolsky-like master equations and the corresponding radial equations with various spins. We find that taking the separable gauge introduced in previous study simplifies the unified form. We also discuss the structure of the radial equation as an ordinary differential equation, such as the existence of the regular and the irregular singularities of the equation and the behavior of the solution around each singularity.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"13 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862985","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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