Pub Date : 2025-03-19DOI: 10.1088/1475-7516/2025/03/037
G. Angloher, M.R. Bharadwaj, M. Cababie, I. Colantoni, I. Dafinei, A.L. De Santis, N. Di Marco, L. Einfalt, F. Ferella, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, Z. Ge, M. Heikinheimo, M.N. Hughes, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, P. Schreiner, C. Schwertner, K. Shera, M. Stahlberg, A. Stendahl, M. Stukel, C. Tresca, F. Wagner, S. Yue, V. Zema, Y. Zhu and G. Pagliaroli
While neutrinos are often treated as a background for many dark matter experiments, these particles offer a new avenue for physics: the detection of core-collapse supernovae. Supernovae are extremely energetic, violent and complex events that mark the death of massive stars. During their collapse stars emit a large number of neutrinos in a short burst. These neutrinos carry 99% of the emitted energy which makes their detection fundamental in understanding supernovae. This paper illustrates how COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches), a sodium iodide (NaI) based dark matter search, will be sensitive to the next galactic core-collapse supernova. The experiment is composed of two separate detectors which will respond to far away and nearby supernovae. The inner core of the experiment will consist of NaI crystals operating as scintillating calorimeters. These crystals will mainly be sensitive to the Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) against Na and I nuclei. The low mass of the cryogenic detectors enables the experiment to identify close supernovae within 1 kpc without pileup. The crystals will see up to hundreds of CEνNS events from a supernova happening at 200 pc. They reside at the center of a large cylindrical 230 T water tank, instrumented with 30 photomultiplier tubes. This tank acts simultaneously as a passive and active shield able to detect the Cherenkov radiation induced by impinging charged particles from ambient and cosmogenic radioactivity. A supernova near the Milky Way Center (10 kpc) will be easily detected inducing ∼60 measurable events, and the water tank will have a 3σ sensitivity to supernovae up to 22 kpc, seeing ∼10 events. This paper shows how, even without dedicated optimization, modern dark matter experiments will also be able to play their part in the multi-messenger effort to detect the next galactic core-collapse supernova.
{"title":"Neutrino flux sensitivity to the next galactic core-collapse supernova in COSINUS","authors":"G. Angloher, M.R. Bharadwaj, M. Cababie, I. Colantoni, I. Dafinei, A.L. De Santis, N. Di Marco, L. Einfalt, F. Ferella, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, Z. Ge, M. Heikinheimo, M.N. Hughes, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, P. Schreiner, C. Schwertner, K. Shera, M. Stahlberg, A. Stendahl, M. Stukel, C. Tresca, F. Wagner, S. Yue, V. Zema, Y. Zhu and G. Pagliaroli","doi":"10.1088/1475-7516/2025/03/037","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/037","url":null,"abstract":"While neutrinos are often treated as a background for many dark matter experiments, these particles offer a new avenue for physics: the detection of core-collapse supernovae. Supernovae are extremely energetic, violent and complex events that mark the death of massive stars. During their collapse stars emit a large number of neutrinos in a short burst. These neutrinos carry 99% of the emitted energy which makes their detection fundamental in understanding supernovae. This paper illustrates how COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches), a sodium iodide (NaI) based dark matter search, will be sensitive to the next galactic core-collapse supernova. The experiment is composed of two separate detectors which will respond to far away and nearby supernovae. The inner core of the experiment will consist of NaI crystals operating as scintillating calorimeters. These crystals will mainly be sensitive to the Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) against Na and I nuclei. The low mass of the cryogenic detectors enables the experiment to identify close supernovae within 1 kpc without pileup. The crystals will see up to hundreds of CEνNS events from a supernova happening at 200 pc. They reside at the center of a large cylindrical 230 T water tank, instrumented with 30 photomultiplier tubes. This tank acts simultaneously as a passive and active shield able to detect the Cherenkov radiation induced by impinging charged particles from ambient and cosmogenic radioactivity. A supernova near the Milky Way Center (10 kpc) will be easily detected inducing ∼60 measurable events, and the water tank will have a 3σ sensitivity to supernovae up to 22 kpc, seeing ∼10 events. This paper shows how, even without dedicated optimization, modern dark matter experiments will also be able to play their part in the multi-messenger effort to detect the next galactic core-collapse supernova.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"11 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653944","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 : 2025-03-19DOI: 10.1088/1475-7516/2025/03/034
A.M. Vicente, J.F. Jesus and S.H. Pereira
In this paper we study the effects of torsion of space-time in the expansion of the Universe as a candidate to dark energy. The analysis is done by reconstructing the torsion function along cosmic evolution by using observational data of Supernovae type Ia, Hubble parameter and Baryon Acoustic Oscillation measurements. We have used a kinematic model for the parameterization of the comoving distance and the Hubble parameter, then the free parameters of the models are constrained by observational data. The reconstruction of the torsion function is obtained directly from the data, using the kinematic parameterizations.
{"title":"Kinematic reconstruction of torsion as dark energy in Friedmann cosmology","authors":"A.M. Vicente, J.F. Jesus and S.H. Pereira","doi":"10.1088/1475-7516/2025/03/034","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/034","url":null,"abstract":"In this paper we study the effects of torsion of space-time in the expansion of the Universe as a candidate to dark energy. The analysis is done by reconstructing the torsion function along cosmic evolution by using observational data of Supernovae type Ia, Hubble parameter and Baryon Acoustic Oscillation measurements. We have used a kinematic model for the parameterization of the comoving distance and the Hubble parameter, then the free parameters of the models are constrained by observational data. The reconstruction of the torsion function is obtained directly from the data, using the kinematic parameterizations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"126 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653940","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 : 2025-03-19DOI: 10.1088/1475-7516/2025/03/036
P. Taule, M. Marinucci, G. Biselli, M. Pietroni and F. Vernizzi
We constrain dark energy and modified gravity within the effective field theory of dark energy framework using the full-shape BOSS galaxy power spectrum, combined with Planck cosmic microwave background (CMB) data and recent baryon acoustic oscillations (BAO) measurements from DESI. Specifically, we focus on a varying braiding parameter αB, a running of the “effective” Planck mass αM, and a constant dark energy equation of state w. The analysis is performed with two of these parameters at a time, including all the other standard cosmological parameters and marginalizing over bias and nuisance parameters. The full-shape galaxy power spectrum is modeled using the effective field theory of large-scale structure up to 1-loop order in perturbation theory. We find that the CMB data is most sensitive to αB, and that adding large-scale structure information only slightly changes the parameter constraints. However, the large-scale structure data significantly improve the bounds on αM and w by a factor of two. This improvement is driven by background information contained in the BAO, which breaks the degeneracy with H0 in the CMB. We confirm this by comparing the BOSS full-shape information with BOSS BAO, finding no significant differences. This is likely to change with future high-precision full-shape data from Euclid and DESI however, to which the pipeline developed here is immediately applicable.
{"title":"Constraints on dark energy and modified gravity from the BOSS Full-Shape and DESI BAO data","authors":"P. Taule, M. Marinucci, G. Biselli, M. Pietroni and F. Vernizzi","doi":"10.1088/1475-7516/2025/03/036","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/036","url":null,"abstract":"We constrain dark energy and modified gravity within the effective field theory of dark energy framework using the full-shape BOSS galaxy power spectrum, combined with Planck cosmic microwave background (CMB) data and recent baryon acoustic oscillations (BAO) measurements from DESI. Specifically, we focus on a varying braiding parameter αB, a running of the “effective” Planck mass αM, and a constant dark energy equation of state w. The analysis is performed with two of these parameters at a time, including all the other standard cosmological parameters and marginalizing over bias and nuisance parameters. The full-shape galaxy power spectrum is modeled using the effective field theory of large-scale structure up to 1-loop order in perturbation theory. We find that the CMB data is most sensitive to αB, and that adding large-scale structure information only slightly changes the parameter constraints. However, the large-scale structure data significantly improve the bounds on αM and w by a factor of two. This improvement is driven by background information contained in the BAO, which breaks the degeneracy with H0 in the CMB. We confirm this by comparing the BOSS full-shape information with BOSS BAO, finding no significant differences. This is likely to change with future high-precision full-shape data from Euclid and DESI however, to which the pipeline developed here is immediately applicable.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"33 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653942","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 : 2025-03-19DOI: 10.1088/1475-7516/2025/03/033
Deepak Kumar, Tuhin Malik and Hiranmaya Mishra
We investigate the intricate relationships between the non-radial f mode oscillation frequencies of neutron stars (NS)s and the corresponding nuclear matter equation of state (EOS) using a machine learning (ML) approach within the ambit of the relativistic mean field (RMF) framework for nuclear matter. With two distinct parametrizations of the Walecka model, namely, (i) with non-linear self interactions of the scalar field (NL) and, (ii) a density dependent Bayesian model (DDB), we perform a thorough examination of the f mode frequency in relation to various nuclear saturation properties. The correlations between the f mode frequencies and nuclear saturation properties reveal, through various analytical and ML methods, the complex nature of NSs and their potential as the cosmic laboratory for studying extreme states of matter. A principal component analysis (PCA) has been performed using mixed datasets from DDB and NL models to discriminate the relative importance of the different components of the EOS on the f mode frequencies. Additionally, a Random forest feature importance analysis also elucidates the distinct roles of these properties in determining the f mode frequency across a spectrum of NS masses. Our findings are further supported by symbolic regression searches, yielding high-accuracy relations with strong Pearson coefficients and minimal errors. These relations suggest new methodologies for probing NS core characteristics, such as energy density, pressure, and speed of sound from observations of non-radial f mode oscillations of NSs.
{"title":"The footprint of nuclear saturation properties on the neutron star f mode oscillation frequencies: a machine learning approach","authors":"Deepak Kumar, Tuhin Malik and Hiranmaya Mishra","doi":"10.1088/1475-7516/2025/03/033","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/033","url":null,"abstract":"We investigate the intricate relationships between the non-radial f mode oscillation frequencies of neutron stars (NS)s and the corresponding nuclear matter equation of state (EOS) using a machine learning (ML) approach within the ambit of the relativistic mean field (RMF) framework for nuclear matter. With two distinct parametrizations of the Walecka model, namely, (i) with non-linear self interactions of the scalar field (NL) and, (ii) a density dependent Bayesian model (DDB), we perform a thorough examination of the f mode frequency in relation to various nuclear saturation properties. The correlations between the f mode frequencies and nuclear saturation properties reveal, through various analytical and ML methods, the complex nature of NSs and their potential as the cosmic laboratory for studying extreme states of matter. A principal component analysis (PCA) has been performed using mixed datasets from DDB and NL models to discriminate the relative importance of the different components of the EOS on the f mode frequencies. Additionally, a Random forest feature importance analysis also elucidates the distinct roles of these properties in determining the f mode frequency across a spectrum of NS masses. Our findings are further supported by symbolic regression searches, yielding high-accuracy relations with strong Pearson coefficients and minimal errors. These relations suggest new methodologies for probing NS core characteristics, such as energy density, pressure, and speed of sound from observations of non-radial f mode oscillations of NSs.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"33 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653939","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 : 2025-03-19DOI: 10.1088/1475-7516/2025/03/032
Ribhu Paul and Sumanta Chakraborty
We have demonstrated that the wavefunction describing the quantum nature of the spacetime inside the black hole horizon, vanishes near the singularity, using the path integral formalism. This is akin to the DeWitt criterion, applied to the interior of a Schwarzschild black hole. To achieve the same we have expressed the interior of a Schwarzschild black hole as a Kantowski-Sachs spacetime and have applied the minisuperspace formalism to determine an exact form of the propagator, and hence the wavefunction near the singularity, using path integral over the reduced phase space. It is to be emphasized that our result is exact and not a saddle point approximation to the path integral.
{"title":"Singularity avoidance from path integral","authors":"Ribhu Paul and Sumanta Chakraborty","doi":"10.1088/1475-7516/2025/03/032","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/032","url":null,"abstract":"We have demonstrated that the wavefunction describing the quantum nature of the spacetime inside the black hole horizon, vanishes near the singularity, using the path integral formalism. This is akin to the DeWitt criterion, applied to the interior of a Schwarzschild black hole. To achieve the same we have expressed the interior of a Schwarzschild black hole as a Kantowski-Sachs spacetime and have applied the minisuperspace formalism to determine an exact form of the propagator, and hence the wavefunction near the singularity, using path integral over the reduced phase space. It is to be emphasized that our result is exact and not a saddle point approximation to the path integral.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"8 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653905","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 : 2025-03-19DOI: 10.1088/1475-7516/2025/03/035
Constantinos Skordis and David M.J. Vokrouhlický
The Aether Scalar Tensor (AeST) theory is an extension of general relativity (GR) successful at reproducing galactic rotational curves, gravitational lensing, linear large scale structure and cosmic microwave background power spectrum observations. We solve the most general static spherically symmetric vacuum equations in the strong-field regime of AeST and find two classes of stealth black hole solutions — those with exact GR geometries — containing non-trivial secondary hair. In particular, one of these can be continuously joined to the cosmological solution of AeST. We also derive a non-black hole solution with zero spatial component in the vector field. This result proves the existence of mathematically and observationally consistent candidates for black holes in AeST, and creates a basis for testing the theory in the strong-field regime.
{"title":"Stealth black holes in Aether Scalar Tensor theory","authors":"Constantinos Skordis and David M.J. Vokrouhlický","doi":"10.1088/1475-7516/2025/03/035","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/035","url":null,"abstract":"The Aether Scalar Tensor (AeST) theory is an extension of general relativity (GR) successful at reproducing galactic rotational curves, gravitational lensing, linear large scale structure and cosmic microwave background power spectrum observations. We solve the most general static spherically symmetric vacuum equations in the strong-field regime of AeST and find two classes of stealth black hole solutions — those with exact GR geometries — containing non-trivial secondary hair. In particular, one of these can be continuously joined to the cosmological solution of AeST. We also derive a non-black hole solution with zero spatial component in the vector field. This result proves the existence of mathematically and observationally consistent candidates for black holes in AeST, and creates a basis for testing the theory in the strong-field regime.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"55 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653941","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 : 2025-03-18DOI: 10.1088/1475-7516/2025/03/028
Javier F. Acevedo, Joseph Bramante, Qinrui Liu and Narayani Tyagi
We present a new inelastic dark matter search: neutron stars in dark matter-rich environments capture inelastic dark matter which, for interstate mass splittings between about 45 - 285 MeV, will annihilate away before becoming fully trapped inside the object. This means a sizable fraction of the dark matter particles can annihilate while being outsidethe neutron star, producing neutron star-focused gamma-rays and neutrinos. We analyze this effect for the first time and target the neutron star population in the Galactic Center, where the large dark matter and neutron star content makes this signal most significant. Depending on the assumed neutron star and dark matter distributions, we set constraints on the dark matter-nucleon inelastic cross-section using existing H.E.S.S. observations. We also forecast the sensitivity of upcoming gamma-ray and neutrino telescopes to this signal, which can reach inelastic cross-sections as low as ∼ 2 × 10-47 cm2.
{"title":"Neutrino and gamma-ray signatures of inelastic dark matter annihilating outside neutron stars","authors":"Javier F. Acevedo, Joseph Bramante, Qinrui Liu and Narayani Tyagi","doi":"10.1088/1475-7516/2025/03/028","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/028","url":null,"abstract":"We present a new inelastic dark matter search: neutron stars in dark matter-rich environments capture inelastic dark matter which, for interstate mass splittings between about 45 - 285 MeV, will annihilate away before becoming fully trapped inside the object. This means a sizable fraction of the dark matter particles can annihilate while being outsidethe neutron star, producing neutron star-focused gamma-rays and neutrinos. We analyze this effect for the first time and target the neutron star population in the Galactic Center, where the large dark matter and neutron star content makes this signal most significant. Depending on the assumed neutron star and dark matter distributions, we set constraints on the dark matter-nucleon inelastic cross-section using existing H.E.S.S. observations. We also forecast the sensitivity of upcoming gamma-ray and neutrino telescopes to this signal, which can reach inelastic cross-sections as low as ∼ 2 × 10-47 cm2.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"33 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653945","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 : 2025-03-18DOI: 10.1088/1475-7516/2025/03/030
Avik Banerjee, Debtosh Chowdhury, Arpan Hait and Md Sariful Islam
The existence of an early matter-dominated epoch prior to the Big Bang Nucleosynthesis (BBN) may lead to a scenario where the thermal dark matter cools faster than plasma before the radiation-dominated era begins. In the radiation-dominated epoch, dark matter free-streams after it decouples both chemically and kinetically from the plasma. In the presence of an early matter-dominated era, chemical decoupling of the dark matter may succeed by a partial kinetic decoupling before reheating ends, depending upon the contributions of different partial wave amplitudes in the elastic scattering rate of the dark matter. We show that the s-wave scattering is sufficient to partially decouple the dark matter from the plasma, if the entropy injection during the reheating era depends on the bath temperature, while p-wave scattering leads to full decoupling in such cosmological backdrop. The decoupling of dark matter before the end of reheating causes an additional amount of cooling, reducing its free-streaming horizon compared to the usual radiation-dominated cosmology. The enhanced matter perturbations for scales entering the horizon prior to the end of reheating, combined with the reduced free-steaming horizon, increase the number density of sub-earth mass halos. The resulting boost in the dark matter annihilation signatures could offer an intriguing probe to differentiate pre-BBN non-standard cosmological epochs. We show that the free-streaming horizon of the dark matter requires to be smaller than a cut-off to ensure a boost in the sub-earth halo populations. As case studies, we present two examples: one for a scalar dark matter with s-wave elastic scattering and the other one featuring a fermionic dark matter with p-wave elastic scattering. We identify regions of parameter space in both models where the dark matter kinetically decouples during reheating, amplifying small-scale structure formation.
{"title":"Dark matter cooling during early matter-domination boosts sub-earth halos","authors":"Avik Banerjee, Debtosh Chowdhury, Arpan Hait and Md Sariful Islam","doi":"10.1088/1475-7516/2025/03/030","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/030","url":null,"abstract":"The existence of an early matter-dominated epoch prior to the Big Bang Nucleosynthesis (BBN) may lead to a scenario where the thermal dark matter cools faster than plasma before the radiation-dominated era begins. In the radiation-dominated epoch, dark matter free-streams after it decouples both chemically and kinetically from the plasma. In the presence of an early matter-dominated era, chemical decoupling of the dark matter may succeed by a partial kinetic decoupling before reheating ends, depending upon the contributions of different partial wave amplitudes in the elastic scattering rate of the dark matter. We show that the s-wave scattering is sufficient to partially decouple the dark matter from the plasma, if the entropy injection during the reheating era depends on the bath temperature, while p-wave scattering leads to full decoupling in such cosmological backdrop. The decoupling of dark matter before the end of reheating causes an additional amount of cooling, reducing its free-streaming horizon compared to the usual radiation-dominated cosmology. The enhanced matter perturbations for scales entering the horizon prior to the end of reheating, combined with the reduced free-steaming horizon, increase the number density of sub-earth mass halos. The resulting boost in the dark matter annihilation signatures could offer an intriguing probe to differentiate pre-BBN non-standard cosmological epochs. We show that the free-streaming horizon of the dark matter requires to be smaller than a cut-off to ensure a boost in the sub-earth halo populations. As case studies, we present two examples: one for a scalar dark matter with s-wave elastic scattering and the other one featuring a fermionic dark matter with p-wave elastic scattering. We identify regions of parameter space in both models where the dark matter kinetically decouples during reheating, amplifying small-scale structure formation.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"55 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653947","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 : 2025-03-18DOI: 10.1088/1475-7516/2025/03/031
Zhao-Chen Zhang, Xiao-Jun Bi and Peng-Fei Yin
Observations of the velocity dispersion indicate a severe dark matter (DM) deficit in the ultra-diffuse galaxy, NGC1052-DF4 (DF4). The ultra-deep images obtained with the Gemini telescope, which has the deepest imaging data till now, confirm the presence of tidal tails in DF4, suggesting its tidal formation. To enhance tidal effects, we consider the self-interaction among DM particles. Using an N-body simulation in the scenario of self-interacting dark matter (SIDM), we reproduce a DM-deficient galaxy that is consistent with all observational data of DF4. Specifically, our simulation result yields an extremely low DM-to-star mass ratio and a radial surface brightness profile very similar to that from deep images, showing accurate tidal features. By performing simulations with similar tidal effects and various cross-sections of SIDM, we show a significant impact of SIDM on the DM-to-star mass ratio in the central region of the galaxy. Our work confirms that the tidal evolution in the SIDM scenario could be a mechanism for interpreting the formation of DF4.
{"title":"Reproduction of NGC1052-DF4 by self-interacting dark matter: dark matter deficiency and tidal features","authors":"Zhao-Chen Zhang, Xiao-Jun Bi and Peng-Fei Yin","doi":"10.1088/1475-7516/2025/03/031","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/03/031","url":null,"abstract":"Observations of the velocity dispersion indicate a severe dark matter (DM) deficit in the ultra-diffuse galaxy, NGC1052-DF4 (DF4). The ultra-deep images obtained with the Gemini telescope, which has the deepest imaging data till now, confirm the presence of tidal tails in DF4, suggesting its tidal formation. To enhance tidal effects, we consider the self-interaction among DM particles. Using an N-body simulation in the scenario of self-interacting dark matter (SIDM), we reproduce a DM-deficient galaxy that is consistent with all observational data of DF4. Specifically, our simulation result yields an extremely low DM-to-star mass ratio and a radial surface brightness profile very similar to that from deep images, showing accurate tidal features. By performing simulations with similar tidal effects and various cross-sections of SIDM, we show a significant impact of SIDM on the DM-to-star mass ratio in the central region of the galaxy. Our work confirms that the tidal evolution in the SIDM scenario could be a mechanism for interpreting the formation of DF4.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"25 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653948","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 : 2025-03-18DOI: 10.1088/1475-7516/2025/03/029
Francesco Benetti, Andrea Lapi, Samuele Silveravalle and Stefano Liberati
In the framework of a collisionless dark matter fluid which is non-minimally coupled to gravity, we investigate the existence and properties of static, spherically symmetric solutions of the general relativistic field equations. We show that the non-minimal coupling originates an (anisotropic) pressure able to counteract gravity and to allow the formation of regular, horizonless ultra-compact objects of dark matter (NMC-UCOs). We then analyze the orbits of massive and massless particles in the gravitational field of NMC-UCOs, providing some specific example and a general discussion in terms of phase portraits. Finally, we study the gravitational lensing effects around NMC-UCOs, and effectively describe these in terms of a pseudo-shadow.
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