Pub Date : 2024-09-02DOI: 10.1088/1475-7516/2024/09/010
Xin Su, Chen-Hao Hao, Ji-Rong Ren and Yong-Qiang Wang
In this paper, we present the spherically symmetric Proca star in the presence of a phantom field and obtain a traversable wormhole solution for non-trivial topological spacetime. Using numerical methods, symmetric solutions and asymmetric solutions are obtained in two asymptotically flat regions. We find that when changing the throat size r0, both the ADM mass M and the Noether charge Q no longer have the spiral characteristics of a classic Proca star, furthermore, the asymmetric solution can be turned into the symmetric solution at some frequency ω in certain r0. In particular, we find that when the frequency takes a certain value, the similar “black-bounce” structure will appear.
{"title":"Proca stars in wormhole spacetime","authors":"Xin Su, Chen-Hao Hao, Ji-Rong Ren and Yong-Qiang Wang","doi":"10.1088/1475-7516/2024/09/010","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/010","url":null,"abstract":"In this paper, we present the spherically symmetric Proca star in the presence of a phantom field and obtain a traversable wormhole solution for non-trivial topological spacetime. Using numerical methods, symmetric solutions and asymmetric solutions are obtained in two asymptotically flat regions. We find that when changing the throat size r0, both the ADM mass M and the Noether charge Q no longer have the spiral characteristics of a classic Proca star, furthermore, the asymmetric solution can be turned into the symmetric solution at some frequency ω in certain r0. In particular, we find that when the frequency takes a certain value, the similar “black-bounce” structure will appear.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123775","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/001
Chams Gharib Ali Barura, Hajime Kobayashi, Shinji Mukohyama, Naritaka Oshita, Kazufumi Takahashi and Vicharit Yingcharoenrat
We study static tidal Love numbers (TLNs) of a static and spherically symmetric black hole for odd-parity metric perturbations. We describe black hole perturbations using the effective field theory (EFT), formulated on an arbitrary background with a timelike scalar profile in the context of scalar-tensor theories. In particular, we obtain a static solution for the generalized Regge-Wheeler equation order by order in a modified-gravity parameter and extract the TLNs uniquely by analytic continuation of the multipole index ℓ to non-integer values. For a stealth Schwarzschild black hole, the TLNs are vanishing as in the case of Schwarzschild solution in general relativity. We also study the case of Hayward black hole as an example of non-stealth background, where we find that the TLNs are non-zero (or there is a logarithmic running). This result suggests that our EFT allows for non-vanishing TLNs and can in principle leave a detectable imprint on gravitational waves from inspiralling binary systems, which opens a new window for testing gravity in the strong-field regime.
{"title":"Tidal Love numbers from EFT of black hole perturbations with timelike scalar profile","authors":"Chams Gharib Ali Barura, Hajime Kobayashi, Shinji Mukohyama, Naritaka Oshita, Kazufumi Takahashi and Vicharit Yingcharoenrat","doi":"10.1088/1475-7516/2024/09/001","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/001","url":null,"abstract":"We study static tidal Love numbers (TLNs) of a static and spherically symmetric black hole for odd-parity metric perturbations. We describe black hole perturbations using the effective field theory (EFT), formulated on an arbitrary background with a timelike scalar profile in the context of scalar-tensor theories. In particular, we obtain a static solution for the generalized Regge-Wheeler equation order by order in a modified-gravity parameter and extract the TLNs uniquely by analytic continuation of the multipole index ℓ to non-integer values. For a stealth Schwarzschild black hole, the TLNs are vanishing as in the case of Schwarzschild solution in general relativity. We also study the case of Hayward black hole as an example of non-stealth background, where we find that the TLNs are non-zero (or there is a logarithmic running). This result suggests that our EFT allows for non-vanishing TLNs and can in principle leave a detectable imprint on gravitational waves from inspiralling binary systems, which opens a new window for testing gravity in the strong-field regime.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118233","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/003
Anjan Kumar Sarkar and Shiv K. Sethi
The presence of massive neutrinos has still not been revealed by the cosmological data. We consider a novel method based on the two-point line-of-sight correlation function of high-resolution Lyman-α data to achieve this end in the paper. We adopt semi-analytic models of Lyman-α clouds for the study. We employ Fisher matrix technique to show that it is possible to achieve a scenario in which the covariance of the two-point function nearly vanishes for both the spectroscopic noise and the signal. We analyze this near `zero noise' outcome in detail to argue it might be possible to detect neutrinos of mass range mν ≃ 0.05–0.1 eV with signal-to-noise of unity with a single QSO line of sight. We show that this estimate can be improved to SNR ≃ 3–6 with data along multiple line of sights within the redshift range z ≃ 2–2.5. Such data sets already exist in the literature. We further carry out principal component analysis of the Fisher matrix to study the degeneracies of the neutrino mass with other parameters. We show that Planck priors lift the degeneracies between the neutrino mass and other cosmological parameters. However, the prospects of the detection of neutrino mass are driven by the poorly-determined parameters characterizing the ionization and thermal state of Lyman-α clouds. We have also mentioned the possible limitations and observational challenges posed in measuring the neutrino mass using our method.
宇宙学数据尚未揭示大质量中微子的存在。我们在文中考虑采用一种基于高分辨率莱曼-α数据的两点视线相关函数的新方法来实现这一目的。我们采用半解析的莱曼-α云模型进行研究。我们采用费雪矩阵技术证明，有可能实现光谱噪声和信号的两点函数协方差都几乎消失的情况。我们详细分析了这种近乎 "零噪声 "的结果，认为有可能用一条 QSO 视线探测到质量范围 mν ≃ 0.05-0.1 eV 的中微子，信噪比为 1。我们的研究表明，利用红移范围 z ≃ 2-2.5 内的多条视线数据，可以将这一估计值提高到信噪比 ȣ3-6。这类数据集已经存在于文献中。我们进一步对费舍尔矩阵进行了主成分分析，以研究中微子质量与其他参数的退行性。我们发现普朗克先验解除了中微子质量与其他宇宙学参数之间的退行性。然而，中微子质量的探测前景受到莱曼-α云电离和热状态特征参数不确定的影响。我们还提到了使用我们的方法测量中微子质量可能存在的局限性和观测挑战。
{"title":"Weighing massive neutrinos with Lyman-α observations","authors":"Anjan Kumar Sarkar and Shiv K. Sethi","doi":"10.1088/1475-7516/2024/09/003","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/003","url":null,"abstract":"The presence of massive neutrinos has still not been revealed by the cosmological data. We consider a novel method based on the two-point line-of-sight correlation function of high-resolution Lyman-α data to achieve this end in the paper. We adopt semi-analytic models of Lyman-α clouds for the study. We employ Fisher matrix technique to show that it is possible to achieve a scenario in which the covariance of the two-point function nearly vanishes for both the spectroscopic noise and the signal. We analyze this near `zero noise' outcome in detail to argue it might be possible to detect neutrinos of mass range mν ≃ 0.05–0.1 eV with signal-to-noise of unity with a single QSO line of sight. We show that this estimate can be improved to SNR ≃ 3–6 with data along multiple line of sights within the redshift range z ≃ 2–2.5. Such data sets already exist in the literature. We further carry out principal component analysis of the Fisher matrix to study the degeneracies of the neutrino mass with other parameters. We show that Planck priors lift the degeneracies between the neutrino mass and other cosmological parameters. However, the prospects of the detection of neutrino mass are driven by the poorly-determined parameters characterizing the ionization and thermal state of Lyman-α clouds. We have also mentioned the possible limitations and observational challenges posed in measuring the neutrino mass using our method.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118236","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/002
Eric J. Baxter and Shivam Pandey
Gravitational lensing by massive galaxy clusters distorts the observed cosmic microwave background (CMB) on arcminute scales, and these distortions carry information about cluster masses. Standard approaches to extracting cluster mass constraints from the CMB cluster lensing signal are either sub-optimal, ignore important physical or observational effects, are computationally intractable, or require additional work to turn the lensing measurements into constraints on cluster masses. We apply simulation based inference (SBI) using neural likelihood models to the problem. We show that in circumstances where the exact likelihood can be computed, the SBI constraints on cluster masses are in agreement with the exact likelihood, demonstrating that the SBI constraints are close to optimal. In scenarios where the exact likelihood cannot be feasibly computed, SBI still recovers unbiased estimates of individual cluster masses and combined constraints from multiple clusters. SBI will be a powerful tool for constraining the masses of galaxy clusters detected by future cosmic surveys. Code to run the analyses presented here will be made publicly available.
{"title":"Inferring galaxy cluster masses from cosmic microwave background lensing with neural simulation based inference","authors":"Eric J. Baxter and Shivam Pandey","doi":"10.1088/1475-7516/2024/09/002","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/002","url":null,"abstract":"Gravitational lensing by massive galaxy clusters distorts the observed cosmic microwave background (CMB) on arcminute scales, and these distortions carry information about cluster masses. Standard approaches to extracting cluster mass constraints from the CMB cluster lensing signal are either sub-optimal, ignore important physical or observational effects, are computationally intractable, or require additional work to turn the lensing measurements into constraints on cluster masses. We apply simulation based inference (SBI) using neural likelihood models to the problem. We show that in circumstances where the exact likelihood can be computed, the SBI constraints on cluster masses are in agreement with the exact likelihood, demonstrating that the SBI constraints are close to optimal. In scenarios where the exact likelihood cannot be feasibly computed, SBI still recovers unbiased estimates of individual cluster masses and combined constraints from multiple clusters. SBI will be a powerful tool for constraining the masses of galaxy clusters detected by future cosmic surveys. Code to run the analyses presented here will be made publicly available.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118235","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/006
O. Dönmez
Modeling of the shock cone formed around a stationary, hairy Horndeski black hole with Bondi-Hoyle-Lyttleton (BHL) accretion has been conducted. We model the dynamical changes of the shock cone resulting from the interaction of matter with the Horndeski black hole, where the scalar field and spacetime have a strong interaction. The effects of the scalar hair, the black hole rotation parameter, and the impacts of the asymptotic speed have been examined, revealing the influence of these parameters on the shock cone and the trapped QPO modes within the cone. Numerical calculations have shown that the hair parameter significantly affects the formation of the shock cone. As the absolute value of the hair parameter increases, the matter in the region of the shock cone is observed to move away from the black hole horizon. The rate of matter expulsion increases as h/M changes. After h/M < -0.6, a visible change in the physical structure of the shock cone occurs, ultimately leading to the complete removal out of the shock cone. On the other hand, it has been revealed that the asymptotic speed significantly affects the formation of the shock cone. As h/M increases in the negative direction and the asymptotic speed increases, the stagnation point moves closer to the black hole horizon. When the value of the hair parameter changes, the rest-mass density of the matter inside the cone decreases, whereas the opposite is observed with the asymptotic speed. Additionally, the formed shock cone has excited QPO modes. The deformation of the cone due to the hair parameter has led to a change or complete disappearance of the QPOs. Meanwhile, at asymptotic speeds of V∞/c < 0.4, all fundamental frequency modes are formed, while at V∞/c = 0.4, only the azimuthal mode is excited, and 1:2:3:4:… resonance conditions occur. No QPOs have formed at V∞/c = 0.6. The results obtained from numerical calculations have been compared with theoretical studies for M87*, and it has been observed that the possible values of h/M found in the numerical simulations are consistent with the theory. Additionally, the results have been compared with those for the GRS 1915+105 black hole, and the hair parameters corresponding to the observed frequencies have been determined.
{"title":"Bondi-Hoyle-Lyttleton accretion around the rotating hairy Horndeski black hole","authors":"O. Dönmez","doi":"10.1088/1475-7516/2024/09/006","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/006","url":null,"abstract":"Modeling of the shock cone formed around a stationary, hairy Horndeski black hole with Bondi-Hoyle-Lyttleton (BHL) accretion has been conducted. We model the dynamical changes of the shock cone resulting from the interaction of matter with the Horndeski black hole, where the scalar field and spacetime have a strong interaction. The effects of the scalar hair, the black hole rotation parameter, and the impacts of the asymptotic speed have been examined, revealing the influence of these parameters on the shock cone and the trapped QPO modes within the cone. Numerical calculations have shown that the hair parameter significantly affects the formation of the shock cone. As the absolute value of the hair parameter increases, the matter in the region of the shock cone is observed to move away from the black hole horizon. The rate of matter expulsion increases as h/M changes. After h/M < -0.6, a visible change in the physical structure of the shock cone occurs, ultimately leading to the complete removal out of the shock cone. On the other hand, it has been revealed that the asymptotic speed significantly affects the formation of the shock cone. As h/M increases in the negative direction and the asymptotic speed increases, the stagnation point moves closer to the black hole horizon. When the value of the hair parameter changes, the rest-mass density of the matter inside the cone decreases, whereas the opposite is observed with the asymptotic speed. Additionally, the formed shock cone has excited QPO modes. The deformation of the cone due to the hair parameter has led to a change or complete disappearance of the QPOs. Meanwhile, at asymptotic speeds of V∞/c < 0.4, all fundamental frequency modes are formed, while at V∞/c = 0.4, only the azimuthal mode is excited, and 1:2:3:4:… resonance conditions occur. No QPOs have formed at V∞/c = 0.6. The results obtained from numerical calculations have been compared with theoretical studies for M87*, and it has been observed that the possible values of h/M found in the numerical simulations are consistent with the theory. Additionally, the results have been compared with those for the GRS 1915+105 black hole, and the hair parameters corresponding to the observed frequencies have been determined.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118239","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/008
S. Giardiello, M. Gerbino, L. Pagano, D. Alonso, B. Beringue, B. Bolliet, E. Calabrese, G. Coppi, J. Errard, G. Fabbian, I. Harrison, J.C. Hill, H.T. Jense, B. Keating, A. La Posta, M. Lattanzi, A.I. Lonappan, G. Puglisi, C.L. Reichardt and S.M. Simon
We study the effects due to mismatches in passbands, polarization angles, and temperature and polarization calibrations in the context of the upcoming cosmic microwave background experiment Simons Observatory (SO). Using the SO multi-frequency likelihood, we estimate the bias and the degradation of constraining power in cosmological and astrophysical foreground parameters assuming different levels of knowledge of the instrumental effects. We find that incorrect but reasonable assumptions about the values of all the systematics examined here can have significant effects on cosmological analyses, hence requiring marginalization approaches at the likelihood level. When doing so, we find that the most relevant effect is due to bandpass shifts. When marginalizing over them, the posteriors of parameters describing astrophysical microwave foregrounds (such as radio point sources or dust) get degraded, while cosmological parameters constraints are not significantly affected. Marginalization over polarization angles with up to 0.25° uncertainty causes an irrelevant bias ≲ 0.05 σ in all parameters. Marginalization over calibration factors in polarization broadens the constraints on the effective number of relativistic degrees of freedom Neff by a factor 1.2, interpreted here as a proxy parameter for non standard model physics targeted by high-resolution CMB measurements.
{"title":"The Simons Observatory: impact of bandpass, polarization angle and calibration uncertainties on small-scale power spectrum analysis","authors":"S. Giardiello, M. Gerbino, L. Pagano, D. Alonso, B. Beringue, B. Bolliet, E. Calabrese, G. Coppi, J. Errard, G. Fabbian, I. Harrison, J.C. Hill, H.T. Jense, B. Keating, A. La Posta, M. Lattanzi, A.I. Lonappan, G. Puglisi, C.L. Reichardt and S.M. Simon","doi":"10.1088/1475-7516/2024/09/008","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/008","url":null,"abstract":"We study the effects due to mismatches in passbands, polarization angles, and temperature and polarization calibrations in the context of the upcoming cosmic microwave background experiment Simons Observatory (SO). Using the SO multi-frequency likelihood, we estimate the bias and the degradation of constraining power in cosmological and astrophysical foreground parameters assuming different levels of knowledge of the instrumental effects. We find that incorrect but reasonable assumptions about the values of all the systematics examined here can have significant effects on cosmological analyses, hence requiring marginalization approaches at the likelihood level. When doing so, we find that the most relevant effect is due to bandpass shifts. When marginalizing over them, the posteriors of parameters describing astrophysical microwave foregrounds (such as radio point sources or dust) get degraded, while cosmological parameters constraints are not significantly affected. Marginalization over polarization angles with up to 0.25° uncertainty causes an irrelevant bias ≲ 0.05 σ in all parameters. Marginalization over calibration factors in polarization broadens the constraints on the effective number of relativistic degrees of freedom Neff by a factor 1.2, interpreted here as a proxy parameter for non standard model physics targeted by high-resolution CMB measurements.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118241","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/004
Swagata Bera, Dibya Chakraborty, George K. Leontaris and Pramod Shukla
The perturbative LARGE volume scenario (LVS) is a promising moduli stabilisation scheme in which the overall volume modulus of the compactifying Calabi-Yau (CY) threefold is dynamically stabilised to exponentially large values via using only perturbative corrections. In this article, using an orientifold of a K3-fibred CY threefold, we present the global embedding of an inflationary model proposed in the framework of perturbative LVS, in which the overall volume modulus acts as the inflaton field rolling on a nearly flat potential induced by a combination of the α'3-corrections and the so-called log-loop effects. Given that having a concrete global construction facilitates explicit expressions for a set of sub-leading corrections, as a next step, we present a detailed analysis investigating the robustness of the single-field inflationary model against such corrections, in particular those arising from the winding-type string loop corrections and the higher derivative F4-corrections.
{"title":"Inflating in perturbative LVS: global embedding and robustness","authors":"Swagata Bera, Dibya Chakraborty, George K. Leontaris and Pramod Shukla","doi":"10.1088/1475-7516/2024/09/004","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/004","url":null,"abstract":"The perturbative LARGE volume scenario (LVS) is a promising moduli stabilisation scheme in which the overall volume modulus of the compactifying Calabi-Yau (CY) threefold is dynamically stabilised to exponentially large values via using only perturbative corrections. In this article, using an orientifold of a K3-fibred CY threefold, we present the global embedding of an inflationary model proposed in the framework of perturbative LVS, in which the overall volume modulus acts as the inflaton field rolling on a nearly flat potential induced by a combination of the α'3-corrections and the so-called log-loop effects. Given that having a concrete global construction facilitates explicit expressions for a set of sub-leading corrections, as a next step, we present a detailed analysis investigating the robustness of the single-field inflationary model against such corrections, in particular those arising from the winding-type string loop corrections and the higher derivative F4-corrections.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118237","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/007
Anirban Biswas, Arpan Kar, Bum-Hoon Lee, Hocheol Lee, Wonwoo Lee, Stefano Scopel, Liliana Velasco-Sevilla and Lu Yin
We provide a transparent discussion of the high temperature asymptotic behaviour of Cosmology in a dilaton-Einstein-Gauss-Bonnet (dEGB) scenario of modified gravity with vanishing scalar potential. In particular, we show that it has a clear interpretation in terms of only three attractors (stable critical points) of a set of autonomous differential equations: w = -1/3, w = 1 and 1 < w < 7/3, where w ≡ p/ρ is the equation of state, defined as the ratio of the total pressure and the total energy density. All the possible different high-temperature evolution histories of the model are exhausted by only eight paths in the flow of the set of the autonomous differential equations. Our discussion clearly explains why five out of them are characterized by a swift transition of the system toward the attractor, while the remaining three show a more convoluted evolution, where the system follows a meta-stable equation of state at intermediate temperatures before eventually jumping to the real attractor at higher temperatures. Compared to standard Cosmology, the regions of the dEGB parameter space with w = -1/3 show a strong enhancement of the expected Gravitational Wave stochastic background produced by the primordial plasma of relativistic particles of the Standard Model. This is due to the very peculiar fact that dEGB allows to have an epoch when the energy density ρrad of the relativistic plasma dominates the energy of the Universe while at the same time the rate of dilution with T of the total energy density is slower than what usually expected during radiation dominance. This allows to use the bound from Big Bang Nucleosynthesis (BBN) to put in dEGB a constraint TRH ≲ (108 – 109) GeV on the reheating temperature of the Universe TRH. Such BBN bound is complementary to late-time constraints from compact binary mergers.
我们对具有消失标量势的稀释-爱因斯坦-高斯-波奈（dEGB）修正引力情景下宇宙学的高温渐近行为进行了透明的讨论。特别是，我们证明它可以用一组自主微分方程的三个吸引点（稳定临界点）来清楚地解释：w =-1/3，w = 1 和 1 < w < 7/3，其中 w ≡ p/ρ 是状态方程，定义为总压力和总能量密度之比。在自主微分方程组的流程中，只有八条路径可以穷尽模型所有可能的不同高温演化历史。我们的讨论清楚地解释了为什么其中五条路径的特点是系统迅速向吸引子过渡，而其余三条路径的演化则更为曲折，系统在中间温度下遵循元稳定状态方程，最终在较高温度下跃迁到真正的吸引子。与标准宇宙学相比，w = -1/3 的 dEGB 参数空间区域显示出标准模型相对论粒子原始等离子体产生的预期引力波随机背景的强烈增强。这是由于一个非常奇特的事实：当相对论等离子体的能量密度ρrad主导宇宙能量时，dEGB允许存在一个纪元，与此同时，总能量密度随T的稀释速度比通常预期的辐射主导时要慢。这使得我们可以利用大爆炸核合成（BBN）的约束，在 dEGB 中对宇宙的再热温度 TRH ≲ (108 - 109) GeV 进行约束。这种BBN约束是对来自紧凑双星合并的晚期约束的补充。
{"title":"Gauss-Bonnet Cosmology: large-temperature behaviour and bounds from Gravitational Waves","authors":"Anirban Biswas, Arpan Kar, Bum-Hoon Lee, Hocheol Lee, Wonwoo Lee, Stefano Scopel, Liliana Velasco-Sevilla and Lu Yin","doi":"10.1088/1475-7516/2024/09/007","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/007","url":null,"abstract":"We provide a transparent discussion of the high temperature asymptotic behaviour of Cosmology in a dilaton-Einstein-Gauss-Bonnet (dEGB) scenario of modified gravity with vanishing scalar potential. In particular, we show that it has a clear interpretation in terms of only three attractors (stable critical points) of a set of autonomous differential equations: w = -1/3, w = 1 and 1 < w < 7/3, where w ≡ p/ρ is the equation of state, defined as the ratio of the total pressure and the total energy density. All the possible different high-temperature evolution histories of the model are exhausted by only eight paths in the flow of the set of the autonomous differential equations. Our discussion clearly explains why five out of them are characterized by a swift transition of the system toward the attractor, while the remaining three show a more convoluted evolution, where the system follows a meta-stable equation of state at intermediate temperatures before eventually jumping to the real attractor at higher temperatures. Compared to standard Cosmology, the regions of the dEGB parameter space with w = -1/3 show a strong enhancement of the expected Gravitational Wave stochastic background produced by the primordial plasma of relativistic particles of the Standard Model. This is due to the very peculiar fact that dEGB allows to have an epoch when the energy density ρrad of the relativistic plasma dominates the energy of the Universe while at the same time the rate of dilution with T of the total energy density is slower than what usually expected during radiation dominance. This allows to use the bound from Big Bang Nucleosynthesis (BBN) to put in dEGB a constraint TRH ≲ (108 – 109) GeV on the reheating temperature of the Universe TRH. Such BBN bound is complementary to late-time constraints from compact binary mergers.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118240","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 : 2024-09-01DOI: 10.1088/1475-7516/2024/09/005
J. Aschersleben, G. Bertone, D. Horns, E. Moulin, R.F. Peletier and M. Vecchi
Intermediate Mass Black Holes (IMBHs) with a mass range between 100 M⊙ and 106 M⊙ are expected to be surrounded by high dark matter densities, so-called dark matter spikes. The high density of self-annihilating Weakly Interacting Massive Particles (WIMPs) in these spikes leads to copious gamma-ray production. Sufficiently nearby IMBHs could therefore appear as unidentified gamma-ray sources. However, the number of IMBHs and their distribution within our own Milky Way is currently unknown. In this work, we provide a mock catalogue of IMBHs and their dark matter spikes obtained from the EAGLE simulations, in which black holes with a mass of 105 M⊙/h are seeded into the centre of halos greater than 1010 M⊙/h to model black hole feedback influencing the formation of galaxies. The catalogue contains the coordinates and dark matter spike parameters for about 2500 IMBHs present in about 150 Milky Way-like galaxies. We expect about 15+9-6 IMBHs within our own galaxy, mainly distributed in the Galactic Centre and the Galactic Plane. In the most optimistic scenario, we find that current and future gamma-ray observatories, such as Fermi-LAT, H.E.S.S. and CTAO, would be sensitive enough to probe the cross section of dark matter self-annihilation around IMBHs down to many orders of magnitude below the thermal relic cross section for dark matter particles with masses from GeV to TeV. We have made the IMBH mock catalogue and the source code for our analysis publicly available, providing the resources to study dark matter self-annihilation around IMBHs with current and upcoming gamma-ray observatories.
{"title":"Gamma rays from dark matter spikes in EAGLE simulations","authors":"J. Aschersleben, G. Bertone, D. Horns, E. Moulin, R.F. Peletier and M. Vecchi","doi":"10.1088/1475-7516/2024/09/005","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/09/005","url":null,"abstract":"Intermediate Mass Black Holes (IMBHs) with a mass range between 100 M⊙ and 106 M⊙ are expected to be surrounded by high dark matter densities, so-called dark matter spikes. The high density of self-annihilating Weakly Interacting Massive Particles (WIMPs) in these spikes leads to copious gamma-ray production. Sufficiently nearby IMBHs could therefore appear as unidentified gamma-ray sources. However, the number of IMBHs and their distribution within our own Milky Way is currently unknown. In this work, we provide a mock catalogue of IMBHs and their dark matter spikes obtained from the EAGLE simulations, in which black holes with a mass of 105 M⊙/h are seeded into the centre of halos greater than 1010 M⊙/h to model black hole feedback influencing the formation of galaxies. The catalogue contains the coordinates and dark matter spike parameters for about 2500 IMBHs present in about 150 Milky Way-like galaxies. We expect about 15+9-6 IMBHs within our own galaxy, mainly distributed in the Galactic Centre and the Galactic Plane. In the most optimistic scenario, we find that current and future gamma-ray observatories, such as Fermi-LAT, H.E.S.S. and CTAO, would be sensitive enough to probe the cross section of dark matter self-annihilation around IMBHs down to many orders of magnitude below the thermal relic cross section for dark matter particles with masses from GeV to TeV. We have made the IMBH mock catalogue and the source code for our analysis publicly available, providing the resources to study dark matter self-annihilation around IMBHs with current and upcoming gamma-ray observatories.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118238","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 : 2024-08-29DOI: 10.1088/1475-7516/2024/08/065
Nico Schuster, Nico Hamaus, Klaus Dolag and Jochen Weller
We utilize the Magneticum suite of state-of-the-art hydrodynamical, as well as dark-matter-only simulations to investigate the effects of baryonic physics on cosmic voids in the highest-resolution study of its kind. This includes the size, shape and inner density distributions of voids, as well as their radial density and velocity profiles traced by (sub-) halos, baryonic and cold dark matter particles. Our results reveal observationally insignificant effects that slightly increase with the inner densities of voids and are exclusively relevant on scales of only a few Mpc. Most notably, we identify deviations in the distributions of baryons and cold dark matter around halo-defined voids, relevant for weak lensing studies. In contrast, we find that voids identified in cold dark matter, as well as in halos of fixed tracer density exhibit nearly indistinguishable distributions and profiles between hydrodynamical and dark-matter-only simulations, consolidating the universality and robustness of the latter for comparisons of void statistics with observations in upcoming surveys. This corroborates that voids are the components of the cosmic web that are least affected by baryonic physics, further enhancing their use as cosmological probes.
{"title":"Why cosmic voids matter: mitigation of baryonic physics","authors":"Nico Schuster, Nico Hamaus, Klaus Dolag and Jochen Weller","doi":"10.1088/1475-7516/2024/08/065","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/08/065","url":null,"abstract":"We utilize the Magneticum suite of state-of-the-art hydrodynamical, as well as dark-matter-only simulations to investigate the effects of baryonic physics on cosmic voids in the highest-resolution study of its kind. This includes the size, shape and inner density distributions of voids, as well as their radial density and velocity profiles traced by (sub-) halos, baryonic and cold dark matter particles. Our results reveal observationally insignificant effects that slightly increase with the inner densities of voids and are exclusively relevant on scales of only a few Mpc. Most notably, we identify deviations in the distributions of baryons and cold dark matter around halo-defined voids, relevant for weak lensing studies. In contrast, we find that voids identified in cold dark matter, as well as in halos of fixed tracer density exhibit nearly indistinguishable distributions and profiles between hydrodynamical and dark-matter-only simulations, consolidating the universality and robustness of the latter for comparisons of void statistics with observations in upcoming surveys. This corroborates that voids are the components of the cosmic web that are least affected by baryonic physics, further enhancing their use as cosmological probes.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":null,"pages":null},"PeriodicalIF":6.4,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100965","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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