Pub Date : 2024-12-17DOI: 10.1088/1475-7516/2024/12/044
Masazumi Honda, Ryusuke Jinno and Koki Tokeshi
The stochastic formalism of inflation allows us to describe the scalar-field dynamics in a non-perturbative way. The correspondence between the diffusion and Schrödinger equations makes it possible to exhaustively construct analytical solutions in stochastic inflation. Those exact statistical quantities such as distribution and correlation functions have one-to-one correspondence to the exactly solvable solutions in non-relativistic quantum mechanics in terms of classical orthogonal polynomials. A class of such solutions is presented by means of isospectral Hamiltonians with an underlying symmetry called shape invariance.
{"title":"Exactly solvable stochastic spectator","authors":"Masazumi Honda, Ryusuke Jinno and Koki Tokeshi","doi":"10.1088/1475-7516/2024/12/044","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/044","url":null,"abstract":"The stochastic formalism of inflation allows us to describe the scalar-field dynamics in a non-perturbative way. The correspondence between the diffusion and Schrödinger equations makes it possible to exhaustively construct analytical solutions in stochastic inflation. Those exact statistical quantities such as distribution and correlation functions have one-to-one correspondence to the exactly solvable solutions in non-relativistic quantum mechanics in terms of classical orthogonal polynomials. A class of such solutions is presented by means of isospectral Hamiltonians with an underlying symmetry called shape invariance.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"1 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832193","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}
Because of their extreme densities and consequently, gravitational potential, compact objects such as neutron stars can prove to be excellent captors of dark matter particles. Considering purely gravitational interactions between dark and hadronic matter, we construct dark matter admixed stars composed of two-fluid matter subject to current astrophysical constraints on maximum mass and tidal deformability. We choose a wide range of parameters to construct the dark matter equation of state, and the DDME2 parameterization for the hadronic equation of state. We then examine the effect of dark matter on the stellar structure, tidal deformability and non-radial modes considering the relativistic Cowling approximation. We find the effect on p-modes is substantial, with frequencies decreasing up to the typical f-mode frequency range for most stars with a dark matter halo. The effects on the f-mode frequency are less extreme. Finally, we find the most probable values of the dark matter parameters that satisfy the observational constraints.
中子星等紧凑型天体具有极高的密度和引力潜能，因此可以成为暗物质粒子的绝佳捕获器。考虑到暗物质和强子物质之间纯粹的引力相互作用，我们构建了由双流体物质组成的暗物质掺杂星，但受当前天体物理学对最大质量和潮汐变形能力的限制。我们选择了广泛的参数来构建暗物质状态方程，并为强子状态方程选择了 DDME2 参数化。然后，考虑到相对论考林近似，我们研究了暗物质对恒星结构、潮汐变形能力和非径向模式的影响。我们发现对 p 模式的影响是巨大的，对于大多数有暗物质光环的恒星来说，p 模式的频率会降低到典型的 f 模式频率范围。对 f 模式频率的影响则没有那么极端。最后，我们找到了满足观测约束的最可能的暗物质参数值。
{"title":"Exploring non-radial oscillation modes in dark matter admixed neutron stars","authors":"Pratik Thakur, Anil Kumar, Vivek Baruah Thapa, Vishal Parmar and Monika Sinha","doi":"10.1088/1475-7516/2024/12/042","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/042","url":null,"abstract":"Because of their extreme densities and consequently, gravitational potential, compact objects such as neutron stars can prove to be excellent captors of dark matter particles. Considering purely gravitational interactions between dark and hadronic matter, we construct dark matter admixed stars composed of two-fluid matter subject to current astrophysical constraints on maximum mass and tidal deformability. We choose a wide range of parameters to construct the dark matter equation of state, and the DDME2 parameterization for the hadronic equation of state. We then examine the effect of dark matter on the stellar structure, tidal deformability and non-radial modes considering the relativistic Cowling approximation. We find the effect on p-modes is substantial, with frequencies decreasing up to the typical f-mode frequency range for most stars with a dark matter halo. The effects on the f-mode frequency are less extreme. Finally, we find the most probable values of the dark matter parameters that satisfy the observational constraints.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832194","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 : 2024-12-17DOI: 10.1088/1475-7516/2024/12/046
Martin Vollmann, Finn Welzmüller and Lovorka Gajović
So far no diffuse emissions in dwarf spheroidal satellites of the Milky Way have ever been observed. Given that dwarf galaxies are predominantly composed of Dark Matter, the discovery of these signals could offer valuable insights into understanding the nature of Dark Matter. We present “diffSph”, a Python tool which in its present version provides fast predictions of such diffuse signals in radio frequencies. It also features a very comprehensive module for the computation of “J” and “D” factors that are relevant for indirect Dark Matter detection using gamma rays. Routines are coupled to parton-shower algorithms and Dark Matter halo mass functions from state-of-the-art kinematic fits. This code is also useful for testing generic hypotheses (not necessarily associated with any Dark Matter candidate) about the cosmic-ray electron/positron sources in the dwarf galaxies. The diffSph tool has already been employed in searches for diffuse signals from dwarf spheroidal galaxies using the LOw Frequency ARray (LOFAR).
{"title":"diffSph: a Python tool to compute diffuse signals from dwarf spheroidal galaxies","authors":"Martin Vollmann, Finn Welzmüller and Lovorka Gajović","doi":"10.1088/1475-7516/2024/12/046","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/046","url":null,"abstract":"So far no diffuse emissions in dwarf spheroidal satellites of the Milky Way have ever been observed. Given that dwarf galaxies are predominantly composed of Dark Matter, the discovery of these signals could offer valuable insights into understanding the nature of Dark Matter. We present “diffSph”, a Python tool which in its present version provides fast predictions of such diffuse signals in radio frequencies. It also features a very comprehensive module for the computation of “J” and “D” factors that are relevant for indirect Dark Matter detection using gamma rays. Routines are coupled to parton-shower algorithms and Dark Matter halo mass functions from state-of-the-art kinematic fits. This code is also useful for testing generic hypotheses (not necessarily associated with any Dark Matter candidate) about the cosmic-ray electron/positron sources in the dwarf galaxies. The diffSph tool has already been employed in searches for diffuse signals from dwarf spheroidal galaxies using the LOw Frequency ARray (LOFAR).","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"76 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832195","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 : 2024-12-17DOI: 10.1088/1475-7516/2024/12/047
Shafqat Ul Islam, Sushant G. Ghosh and Sunil D. Maharaj
The EHT observation revealed event horizon-scale images of the supermassive black holes Sgr A* and M87* and these results are consistent with the shadow of a Kerr black hole as predicted by general relativity. However, Kerr-like rotating black holes in modified gravity theories can not ruled out, as they provide a crucial testing ground for these theories through EHT observations. It motivates us to investigate the bumblebee theory, a vector-tensor extension of the Einstein-Maxwell theory that permits spontaneous symmetry breaking, resulting in the field acquiring a vacuum expectation value and introducing Lorentz violation. We present rotating black holes within this bumblebee gravity model, which includes an additional parameter ℓ alongside the mass M and spin parameter a — namely RBHBG. Unlike the Kerr black hole, an extremal RBHBG, for ℓ < 0, refers to a black hole with angular momentum a > M. We derive an analytical formula necessary for the shadow of our rotating black holes, then visualize them with varying parameters a and ℓ, and also estimate the black hole parameters using shadow observables viz. shadow radius Rs, distortion δs, shadow area A and oblateness D using two well-known techniques. We find that ℓ incrementally increases the shadow size and causes more significant deformation while decreasing the event horizon area. Remarkably, an increase in ℓ enlarges the shadow radius irrespective of spin or inclination angle θ0.
{"title":"Investigating rotating black holes in bumblebee gravity: insights from EHT observations","authors":"Shafqat Ul Islam, Sushant G. Ghosh and Sunil D. Maharaj","doi":"10.1088/1475-7516/2024/12/047","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/047","url":null,"abstract":"The EHT observation revealed event horizon-scale images of the supermassive black holes Sgr A* and M87* and these results are consistent with the shadow of a Kerr black hole as predicted by general relativity. However, Kerr-like rotating black holes in modified gravity theories can not ruled out, as they provide a crucial testing ground for these theories through EHT observations. It motivates us to investigate the bumblebee theory, a vector-tensor extension of the Einstein-Maxwell theory that permits spontaneous symmetry breaking, resulting in the field acquiring a vacuum expectation value and introducing Lorentz violation. We present rotating black holes within this bumblebee gravity model, which includes an additional parameter ℓ alongside the mass M and spin parameter a — namely RBHBG. Unlike the Kerr black hole, an extremal RBHBG, for ℓ < 0, refers to a black hole with angular momentum a > M. We derive an analytical formula necessary for the shadow of our rotating black holes, then visualize them with varying parameters a and ℓ, and also estimate the black hole parameters using shadow observables viz. shadow radius Rs, distortion δs, shadow area A and oblateness D using two well-known techniques. We find that ℓ incrementally increases the shadow size and causes more significant deformation while decreasing the event horizon area. Remarkably, an increase in ℓ enlarges the shadow radius irrespective of spin or inclination angle θ0.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"4 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832197","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 : 2024-12-17DOI: 10.1088/1475-7516/2024/12/048
Marilena Loverde and Zachary J. Weiner
Cosmological data probe massive neutrinos via their effects on the geometry of the Universe and the growth of structure, both of which are degenerate with the late-time expansion history. We clarify the nature of these degeneracies and the individual roles of both probes in neutrino mass inference. Geometry is strongly sensitive to neutrino masses: within ΛCDM, the primary cosmic microwave background anisotropies alone impose that the matter fraction Ωm must increase fivefold with increasing neutrino mass. Moreover, large-scale structure observables, like weak lensing of the CMB, are dimensionless and thus depend not on the matter density (as often quoted) but in fact the matter fraction. We explore the consequential impact of this distinction on the interplay between probes of structure, low-redshift distances, and CMB anisotropies. We derive constraints on the neutrino's masses independently from their suppression of structure and impact on geometry, showing that the latter is at least as important as the former. While the Dark Energy Spectroscopic Instrument's recent baryon acoustic oscillation data place stringent bounds largely deriving from their geometric incompatibility with massive neutrinos, all recent type Ia supernova datasets drive marginal preferences for nonzero neutrino masses because they prefer substantially larger matter fractions. Recent CMB lensing data, however, neither exclude neutrinos' suppression of structure nor constrain it strongly enough to discriminate between mass hierarchies. Current data thus evince not a need for modified dynamics of neutrino perturbations or structure growth but rather an inconsistent compatibility with massive neutrinos' impact on the expansion history. We identify two of DESI's measurements that strongly influence its constraints, and we also discuss neutrino mass measurements in models that alter the sound horizon.
{"title":"Massive neutrinos and cosmic composition","authors":"Marilena Loverde and Zachary J. Weiner","doi":"10.1088/1475-7516/2024/12/048","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/048","url":null,"abstract":"Cosmological data probe massive neutrinos via their effects on the geometry of the Universe and the growth of structure, both of which are degenerate with the late-time expansion history. We clarify the nature of these degeneracies and the individual roles of both probes in neutrino mass inference. Geometry is strongly sensitive to neutrino masses: within ΛCDM, the primary cosmic microwave background anisotropies alone impose that the matter fraction Ωm must increase fivefold with increasing neutrino mass. Moreover, large-scale structure observables, like weak lensing of the CMB, are dimensionless and thus depend not on the matter density (as often quoted) but in fact the matter fraction. We explore the consequential impact of this distinction on the interplay between probes of structure, low-redshift distances, and CMB anisotropies. We derive constraints on the neutrino's masses independently from their suppression of structure and impact on geometry, showing that the latter is at least as important as the former. While the Dark Energy Spectroscopic Instrument's recent baryon acoustic oscillation data place stringent bounds largely deriving from their geometric incompatibility with massive neutrinos, all recent type Ia supernova datasets drive marginal preferences for nonzero neutrino masses because they prefer substantially larger matter fractions. Recent CMB lensing data, however, neither exclude neutrinos' suppression of structure nor constrain it strongly enough to discriminate between mass hierarchies. Current data thus evince not a need for modified dynamics of neutrino perturbations or structure growth but rather an inconsistent compatibility with massive neutrinos' impact on the expansion history. We identify two of DESI's measurements that strongly influence its constraints, and we also discuss neutrino mass measurements in models that alter the sound horizon.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832196","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 : 2024-12-13DOI: 10.1088/1475-7516/2024/12/040
Massimo Bianchi, Giuseppe Dibitetto and Jose Francisco Morales
We reconsider linear perturbations around general Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological backgrounds. Exploiting gauge freedom involving only time reparametrizations, we write down classical background solutions analytically, for an arbitrary number of fluid components. We then show that the time evolution of scalar and tensor adiabatic perturbations are governed by Schrödinger-like differential equations of generalized Heun type. After recovering known analytic results for a single-component fluid, we discuss more general situations with two and three different fluid components, with special attention to the combination of radiation, matter and vacuum energy, which is supposed to describe the ΛCDM model. The evolution of linear perturbations of a flat ΛCDM universe is described by a two-transient model, where the transitions from radiation to matter and matter to vacuum energy are governed by a Heun equation and a Hypergeometric equation, respectively. We discuss an analytic approach to the study of the general case, involving generalized Heun equations, that makes use of (quantum) Seiberg-Witten curves for 𝒩 = 2 supersymmetric gauge theories and has proven to be very effective in the analysis of Black-Hole, fuzzball and ECO perturbations.
{"title":"Gauge theory meets cosmology","authors":"Massimo Bianchi, Giuseppe Dibitetto and Jose Francisco Morales","doi":"10.1088/1475-7516/2024/12/040","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/040","url":null,"abstract":"We reconsider linear perturbations around general Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological backgrounds. Exploiting gauge freedom involving only time reparametrizations, we write down classical background solutions analytically, for an arbitrary number of fluid components. We then show that the time evolution of scalar and tensor adiabatic perturbations are governed by Schrödinger-like differential equations of generalized Heun type. After recovering known analytic results for a single-component fluid, we discuss more general situations with two and three different fluid components, with special attention to the combination of radiation, matter and vacuum energy, which is supposed to describe the ΛCDM model. The evolution of linear perturbations of a flat ΛCDM universe is described by a two-transient model, where the transitions from radiation to matter and matter to vacuum energy are governed by a Heun equation and a Hypergeometric equation, respectively. We discuss an analytic approach to the study of the general case, involving generalized Heun equations, that makes use of (quantum) Seiberg-Witten curves for 𝒩 = 2 supersymmetric gauge theories and has proven to be very effective in the analysis of Black-Hole, fuzzball and ECO perturbations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"4 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815653","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 : 2024-12-13DOI: 10.1088/1475-7516/2024/12/038
Dhiraj Kumar Hazra, Benjamin Beringue, Josquin Errard, Arman Shafieloo and George F. Smoot
We explore the scales and the extent of disagreement between Planck PR3 and Atacama Cosmology Telescope (ACT) DR4 data. Planck and ACT data have substantial overlap in the temperature anisotropy data between scales corresponding to multipoles ℓ ≃ 600–2500 with complementing coverage of larger angular scales by Planck and smaller angular scales by ACT. Since the same cosmology should govern the anisotropy spectrum at all scales, we probe this disagreement in the primordial power spectrum. We use a parametric form of power law primordial spectrum that allows changes in the spectral tilt. We also reconstruct the primordial spectrum with a non-parametric method from both Planck and ACT temperature data. We find the disagreement exists within scales 0.08–0.16 Mpc-1 where ACT temperature data prefers a scale invariant/blue spectrum. At scales larger and smaller than this window, ACT data strongly prefers a red tilt, which is consistent with Planck. This change in the spectral tilt can be identified in the ACT data at 2σ C.L. without using Planck data, indicating that the tension is driven by different preferences for tilts within the ACT data. The addition of Planck data up to intermediate scales (ℓ ≤ 650) increases this significance to 3σ. Given the large overlap between Planck and ACT within 0.08–0.16 Mpc-1 and considering the internal consistency between different Planck temperature and polarization spectra, the scope of new physics as a solution to the tension remains limited. Our results — a strong preference for an intermediate transition in spectral tilt and the variation of this preference in different data combinations — indicate that systematic effects can be misperceived as new physics emerging from different non-standard cosmological processes.
{"title":"Exploring the discrepancy between Planck PR3 and ACT DR4","authors":"Dhiraj Kumar Hazra, Benjamin Beringue, Josquin Errard, Arman Shafieloo and George F. Smoot","doi":"10.1088/1475-7516/2024/12/038","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/038","url":null,"abstract":"We explore the scales and the extent of disagreement between Planck PR3 and Atacama Cosmology Telescope (ACT) DR4 data. Planck and ACT data have substantial overlap in the temperature anisotropy data between scales corresponding to multipoles ℓ ≃ 600–2500 with complementing coverage of larger angular scales by Planck and smaller angular scales by ACT. Since the same cosmology should govern the anisotropy spectrum at all scales, we probe this disagreement in the primordial power spectrum. We use a parametric form of power law primordial spectrum that allows changes in the spectral tilt. We also reconstruct the primordial spectrum with a non-parametric method from both Planck and ACT temperature data. We find the disagreement exists within scales 0.08–0.16 Mpc-1 where ACT temperature data prefers a scale invariant/blue spectrum. At scales larger and smaller than this window, ACT data strongly prefers a red tilt, which is consistent with Planck. This change in the spectral tilt can be identified in the ACT data at 2σ C.L. without using Planck data, indicating that the tension is driven by different preferences for tilts within the ACT data. The addition of Planck data up to intermediate scales (ℓ ≤ 650) increases this significance to 3σ. Given the large overlap between Planck and ACT within 0.08–0.16 Mpc-1 and considering the internal consistency between different Planck temperature and polarization spectra, the scope of new physics as a solution to the tension remains limited. Our results — a strong preference for an intermediate transition in spectral tilt and the variation of this preference in different data combinations — indicate that systematic effects can be misperceived as new physics emerging from different non-standard cosmological processes.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815736","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 : 2024-12-13DOI: 10.1088/1475-7516/2024/12/039
Xin-Chen He, Yi-Fu Cai, Xiao-Han Ma, Theodoros Papanikolaou, Emmanuel N. Saridakis and Misao Sasaki
Ultra-light primordial black holes (PBHs) with masses MPBH < 5 × 108g can dominate transiently the energy budget of the Universe and reheat the Universe through their evaporation taking place before Big Bang Nucleosynthesis. The isocurvature energy density fluctuations associated to the inhomogeneous distribution of a population of such PBHs can induce an abundant production of GWs due to second-order gravitational effects. In this work, we discuss the effect of primordial non-Gaussianity on the clustering properties of PBHs and study the effect of a clustered PBH population on the spectral shape of the aforementioned induced GW signal. In particular, focusing on local-type non-Gaussianity we find a double-peaked GW signal with the amplitude of the low-frequency peak being proportional to the square of the non-Gaussian parameterτNL. Remarkably, depending on the PBH mass MPBH and the initial abundance of PBHs at formation time, i.e. ΩPNH,f, this double-peaked GW signal can lie well within the frequency bands of forthcoming GW detectors, namely LISA, ET, SKA and BBO, hence rendering this signal falsifiable by GW experiments and promoting it as a novel portal probing the primordial non-Gaussianity.
{"title":"Gravitational waves from primordial black hole isocurvature: the effect of non-Gaussianities","authors":"Xin-Chen He, Yi-Fu Cai, Xiao-Han Ma, Theodoros Papanikolaou, Emmanuel N. Saridakis and Misao Sasaki","doi":"10.1088/1475-7516/2024/12/039","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/039","url":null,"abstract":"Ultra-light primordial black holes (PBHs) with masses MPBH < 5 × 108g can dominate transiently the energy budget of the Universe and reheat the Universe through their evaporation taking place before Big Bang Nucleosynthesis. The isocurvature energy density fluctuations associated to the inhomogeneous distribution of a population of such PBHs can induce an abundant production of GWs due to second-order gravitational effects. In this work, we discuss the effect of primordial non-Gaussianity on the clustering properties of PBHs and study the effect of a clustered PBH population on the spectral shape of the aforementioned induced GW signal. In particular, focusing on local-type non-Gaussianity we find a double-peaked GW signal with the amplitude of the low-frequency peak being proportional to the square of the non-Gaussian parameterτNL. Remarkably, depending on the PBH mass MPBH and the initial abundance of PBHs at formation time, i.e. ΩPNH,f, this double-peaked GW signal can lie well within the frequency bands of forthcoming GW detectors, namely LISA, ET, SKA and BBO, hence rendering this signal falsifiable by GW experiments and promoting it as a novel portal probing the primordial non-Gaussianity.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"16 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815734","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 : 2024-12-13DOI: 10.1088/1475-7516/2024/12/037
Javier Reynoso-Cordova, Nassim Bozorgnia and Marie-Cécile Piro
We investigate how the Large Magellanic Cloud (LMC) impacts the predicted signals in near-future direct detection experiments for non-standard dark matter (DM) interactions, using the Auriga cosmological simulations. We extract the local DM distribution of a simulated Milky Way-like halo that has an LMC analogue and study the expected signals in DarkSide-20k, SBC, DARWIN/XLZD, SuperCDMS, NEWS-G, and DarkSPHERE considering DM-nucleon effective interactions, as well as inelastic DM scattering. We find that the LMC causes substantial shifts in direct detection exclusion limits towards smaller cross sections and DM masses for all non-relativistic effective field theory (NREFT) operators, with the impact being highly pronounced for velocity-dependent operators at low DM masses. For inelastic DM, where the DM particle up-scatters to a heavier state, the LMC shifts the direct detection exclusion limits towards larger DM mass splitting and smaller cross sections. Thus, we show that the LMC significantly expands the parameter space that can be probed by direct detection experiments towards smaller DM-nucleon cross sections for all NREFT operators and larger values of mass splitting for inelastic DM.
{"title":"The Large Magellanic Cloud: expanding the low-mass parameter space of dark matter direct detection","authors":"Javier Reynoso-Cordova, Nassim Bozorgnia and Marie-Cécile Piro","doi":"10.1088/1475-7516/2024/12/037","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/037","url":null,"abstract":"We investigate how the Large Magellanic Cloud (LMC) impacts the predicted signals in near-future direct detection experiments for non-standard dark matter (DM) interactions, using the Auriga cosmological simulations. We extract the local DM distribution of a simulated Milky Way-like halo that has an LMC analogue and study the expected signals in DarkSide-20k, SBC, DARWIN/XLZD, SuperCDMS, NEWS-G, and DarkSPHERE considering DM-nucleon effective interactions, as well as inelastic DM scattering. We find that the LMC causes substantial shifts in direct detection exclusion limits towards smaller cross sections and DM masses for all non-relativistic effective field theory (NREFT) operators, with the impact being highly pronounced for velocity-dependent operators at low DM masses. For inelastic DM, where the DM particle up-scatters to a heavier state, the LMC shifts the direct detection exclusion limits towards larger DM mass splitting and smaller cross sections. Thus, we show that the LMC significantly expands the parameter space that can be probed by direct detection experiments towards smaller DM-nucleon cross sections for all NREFT operators and larger values of mass splitting for inelastic DM.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"235 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815730","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 : 2024-12-13DOI: 10.1088/1475-7516/2024/12/041
G.L.A. Dizon and R.C. Reyes
We investigate the projected minimum constraints set by next-generation gravitational wave detectors Einstein Telescope and LISA on the abundance of primordial black holes relative to dark matter from both resolvable mergers and the stochastic gravitational wave background (SGWB) for extended primordial black hole mass distributions. We consider broad power law distributions for a range of negative and positive exponents γ and top-hat distributions (with γ = 0) and use the IMRPhenomXAS waveforms to simulate binary sources up to mass ratios qmax = 1000 and redshifts z = 300. Our results suggest that accounting for extended mass distributions have the most apparent impact when considering mergers at high redshifts z > 30, for which the constraint curves have broader mass windows and shift to higher abundances compared to when a monochromatic distribution is assumed; on the other hand, constraints from low-redshift mergers and the SGWB do not change much with the assumed mass distribution. At high redshifts, astrophysical black holes are not expected to contribute significantly, providing possible smoking-gun evidence for PBHs. Constraints derived from LISA and ET observations would complement each other by probing different PBH mass windows and this holds for the extended mass distributions studied.
{"title":"Projected gravitational wave constraints on primordial black hole abundance for extended mass distributions","authors":"G.L.A. Dizon and R.C. Reyes","doi":"10.1088/1475-7516/2024/12/041","DOIUrl":"https://doi.org/10.1088/1475-7516/2024/12/041","url":null,"abstract":"We investigate the projected minimum constraints set by next-generation gravitational wave detectors Einstein Telescope and LISA on the abundance of primordial black holes relative to dark matter from both resolvable mergers and the stochastic gravitational wave background (SGWB) for extended primordial black hole mass distributions. We consider broad power law distributions for a range of negative and positive exponents γ and top-hat distributions (with γ = 0) and use the IMRPhenomXAS waveforms to simulate binary sources up to mass ratios qmax = 1000 and redshifts z = 300. Our results suggest that accounting for extended mass distributions have the most apparent impact when considering mergers at high redshifts z > 30, for which the constraint curves have broader mass windows and shift to higher abundances compared to when a monochromatic distribution is assumed; on the other hand, constraints from low-redshift mergers and the SGWB do not change much with the assumed mass distribution. At high redshifts, astrophysical black holes are not expected to contribute significantly, providing possible smoking-gun evidence for PBHs. Constraints derived from LISA and ET observations would complement each other by probing different PBH mass windows and this holds for the extended mass distributions studied.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"20 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142815654","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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