Hint of Dark Matter–Dark Energy Interaction in DESI DR2 and Current Cosmological Dataset?

Abstract We combine new spectroscopic observations of the ultrafaint dwarf (UFD) galaxy Boötes I (Boo I) from the Southern Stellar Stream Spectroscopic Survey ( S 5 ) with ∼15 yr of archival spectroscopic data to create the largest sample of stellar kinematics and metallicities to date for any Milky Way UFD. Our combined sample includes 148 members extending out to ∼7 half-light radii ( r h ), including 24 newly confirmed members, 18 binary candidates, 15 RR Lyrae stars, and 92 [Fe/H] measurements. Using this larger and more spatially extended sample, we provide updated constraints on Boo I’s systemic properties, including its radial population gradients. Properly accounting for perspective rotation effects in a UFD for the first time, we detect a 4 σ line-of-sight velocity gradient of 1.2 ± 0.3 km s −1 r h − 1 aligned along Boo I’s orbit and discuss its potential tidal origins. We also infer a metallicity gradient of −0.10 ± 0.02 dex r h − 1 in agreement with previous studies. Using an axisymmetric Jeans model, we provide updated constraints on Boo I’s dark matter density profile, which weakly favors a cusped ( γ = 1 . 0 − 0.6 + 0.5 ) dark matter profile. Lastly, we reanalyze Boo I’s metallicity distribution function with a one-zone galactic chemical evolution model and place new constraints on its rapid, inefficient star formation and strong galactic outflows.

We investigate primordial black hole (PBH) production via the collapse of supercritical domain walls in a quadratic f(R)-gravity model with tensor extensions. The effective field theory for an extra space’s scalar curvature provides a foundation for the formation of these dense walls. In our work, domain walls are found to be supercritical. Their properties were extensively studied in the literature, where it was demonstrated that they create wormholes and escape into baby universes through them. Closure of the wormhole leads to black hole creation, providing a mechanism for the production of primordial black holes in our model. We calculate the mass spectrum of such black holes and mass distribution within clusters of them. When accretion is accounted for, the black holes produced under this mechanism present viable dark matter candidates.

The nature of dark matter (DM) is still debated. While cold DM (CDM) is the standard paradigm, warm DM (WDM) composed of thermal relics may ease some small-scale tensions in the ΛCDM framework. Line-intensity mapping (LIM) offers a novel probe of DM properties. To explore the potential of LIM surveys in constraining the WDM particle mass (m_ by means of the ̧ii power spectrum (PS), we provide forecasts for the Deep Spectroscopic Survey (DSS) to be performed with the Fred Young Submillimeter Telescope at z and extend the analysis to larger sky coverage, higher sensitivity, and/or increased spectral resolution. We developed a formulation for the ̧ii PS based on the halo-model approach, incorporating the uncertainty in the luminosity function (LF) through two alternative parameterisations, one optimistic and the other more conservative. We performed a Bayesian analysis on mock data to derive constraints on m_ In a CDM universe, the DSS yields lower limits on m_ at a 95% credibility level, of 1.10 keV and 0.58 keV when considering the optimistic and pessimistic LF (α = -1.1), respectively. Ambitious surveys can improve these figures to 5.82 keV and 1.90 keV, and assuming a steeper faint-end slope (α = -1.9) further boosts the constraints even beyond those obtained in the optimistic scenario. A fivefold increase in spectral resolution enhances sensitivity to the damping scale associated with redshift-space distortions, tightening the constraints on m_ by a factor of up to sim1.8. Finally, Bayesian inference on mock data with m_ =3 keV results in a well-constrained and unbiased posterior only in futuristic survey setups. WDM Upcoming LIM surveys can provide meaningful limits on m_ although the negligible contribution from small haloes reduces the constraining power of the ̧ii PS. Future progress will benefit from combining multiple redshifts and emission lines, opening the way to competitive constraints on the nature of DM.

Axion dark matter passing through the magnetospheres of magnetars can undergo hyperefficient resonant mixing with low-energy photons, leading to the production of narrow spectral lines that could be detectable on Earth. Since this is a resonant process triggered by the spatial variation in the photon dispersion relation, the luminosity and spectral properties of the emission are highly sensitive to the charge and current densities permeating the magnetosphere. To date, a majority of the studies investigating this phenomenon have assumed a perfectly dipolar magnetic field structure with a near-field plasma distribution fixed to the minimal charge-separated force-free configuration. While this may be a reasonable treatment for the closed field lines of conventional radio pulsars, the strong magnetic fields around magnetars are believed to host processes that drive strong deviations from this minimal configuration. In this work, we study how realistic magnetar magnetospheres impact the electromagnetic emission produced from axion dark matter. Specifically, we construct charge and current distributions that are consistent with magnetar observations and use these to recompute the prospective sensitivity of radio and submillimeter telescopes to axion dark matter. We demonstrate that the two leading models yield vastly different predictions for the frequency and amplitude of the spectral line, indicating systematic uncertainties in the plasma structure are significant. Finally, we discuss various observational signatures that can be used to differentiate the local plasma loading mechanism of an individual magnetar, which will be necessary if there is hope of using such objects to search for axions.

If the dark matter mass m exceeds the maximum temperature of the Universe (T max < m) then its production rate will be Boltzmann suppressed. The important implications of this Boltzmann suppression have been explored for dark matter freeze-in via renormalizable operators. Here we extend these considerations to the case of ultraviolet (UV) freeze-in for which freeze-in proceeds via non-renormalizable operators. The UV freeze-in variant has a number of appealing features, not least that a given effective field theory can describe a multitude of UV completions, and thus such analyses are model agnostic for a given high dimension freeze-in operator. We undertake model independent analyses of UV freeze-in for portal operators of general mass dimensions. Subsequently, we explore a number of specific examples, namely, Higgs portals, bino dark matter, and gravitino dark matter. Finally, we discuss how significant differences arise if one departs from the standard assumptions regarding inflationary reheating (i.e. transitions from an early matter dominated era to radiation domination). As a motivated example we examine the implications of early kination domination. Boltzmann suppressed UV freeze-in is well motivated and permits a number of compelling scenarios. In particular, we highlight that for T max ∼ 1 TeV it is feasible that the freeze-in mechanism is entirely realized within a couple of orders of magnitude of the TeV scale, making it experimentally accessible in contrast to traditional freeze-in scenarios.

Dark matter in White Dwarfs: Implications for their structure

We consider the motion of a particle in the geometry of a Schwarzschild-like black hole embedded in a dark matter (DM) halo with Dehnen type density profile and calculate the orbital periods along with the evolution of the semi-latus rectum and eccentricity for extreme mass ratio inspirals (EMRIs). Such a system emits gravitational waves (GWs), and the particle's orbit evolves under radiation reaction. We also consider the effects of dynamical friction and accretion of DM on the orbital parameters. We find that the eccentricity and semi-latus rectum decrease faster with respect to the case in which EMRI is in empty spacetime.

F-mode oscillations of neutron stars with dark matter from neutron decay: Implications for gravitational-wave detectability

We reconsider primordial black hole physics in Randall-Sundrum Type-II universes, focusing on constraints from cosmological and astrophysical observables. We pay particular attention to scenarios that allow the entirety of dark matter to be in the form of higher-dimensional primordial black holes. This is possible for a range of AdS radii and black hole masses. Observable constraints are generally modified due to the changes in the higher-dimensional gravitational sector, and come from low-energy e ± emission, microlensing, and possibly from contributions to unresolved radiation backgrounds. We discuss constraints from the cosmic microwave background due to injection of Hawking quanta into the intergalactic medium. Finally, we comment on recent discussions on the compatibility of higher-dimensional black holes and the KM3-230213A event.

In this study, we propose an investigation into dark photon dark matter (DPDM) within the infraredfrequency band, utilizing highly sensitive infrared light detectors commonly integrated into spacetelescopes, such as the James Webb Space Telescope (JWST). The presence of DPDM induces electronoscillations in both the reflectors and the interior of the detectors. Consequently, theseoscillating electrons can emit monochromatic electromagnetic waves with a frequency almostequivalent to the mass of DPDM. By employing the stationary phase approximation, we can demonstratethat when the size of the reflector significantly exceeds the wavelength of the electromagneticwave, the contribution to the electromagnetic wave field at a given position primarily stems fromthe surface unit perpendicular to the relative position vector. This simplification results in thereduction of electromagnetic wave calculations to ray optics. Through a careful analysis of photongeneration induced by DPDM on the various optical elements of JWST, we find that the contribution ofthese photons to the detected signal is negligible. Nevertheless, we propose a modifiedconfiguration of the JWST mirrors that would enable the DPDM-induced photons to be focused onto thedetector. This approach can be applied to future space telescopes during their ground-testingphases. Using the JWST parameters as a representative example, the achievable upper limits on theDPDM-photon mixing constant are ϵ ∼ 10-12–10-14 in the frequency range10–500 THz at the 95% confidence level. This reveals the strong potential of future spacetelescopes for DPDM detection during ground testing, with sensitivities exceeding current limits by1 to 2 orders of magnitude compared with the XENON1T result and the solar cooling bound.

The Fast Stochastic Matching Pursuit for neutrino and dark matter experiments

The dark matter paradigm arises from persistent discrepancies between gravitational effects inferred from visible matter and those observed through galaxy rotation curves, gravitational lensing, cluster dynamics, and merging systems such as the Bullet Cluster. Within General Relativity (GR), these discrepancies are resolved by postulating a new, non-baryonic, collisionless matter component. In this work, we demonstrate that dark matter is not required when gravity is reformulated within Dynamic Vacuum Field Theory (DVFT), where the vacuum is a physical medium described by a complex scalar field with amplitude and phase degrees of freedom. We derive gravitational lensing, gravitational slip, parameterized post-Newtonian (PPN) screening, and Shapiro delay directly from DVFT first principles. We show that gravitational slip naturally arises from vacuum anisotropic stress, allowing lensing and dynamics to decouple without invoking unseen mass. Solar-System constraints are satisfied through strong screening, galaxy-scale lenses (SLACS and HE 0435-1223) are reproduced without dark matter halos, and the Bullet Cluster lensing-gas offset emerges as a direct consequence of collisionless vacuum phase dynamics. A quantitative Bullet Cluster calculation yields an effective lensing mass of order within 250 kpc, fully consistent with observations. We conclude that dark matter is a misinterpretation of vacuum stress-energy and gravitational slip, and that DVFT provides a unified, predictive alternative grounded in physical vacuum dynamics.

Dynamic Vacuum Field Theory (DVFT) posits a unified framework where spacetime curvature and quantum phenomena emerge from distortions in a physical vacuum field described by a complex scalar , with as the amplitude (inertial density) and as the phase (coherence and oscillatory behavior). This theory eliminates the need for dark matter particles by attributing gravitational effects in galaxy clusters, such as those observed in the Bullet Cluster (1E 0657-56), to vacuum stress-energy contributions that behave collisionlessly during mergers. We derive the core DVFT equations, including the Lagrangian, stress-energy tensor, and field equations, and apply them to the Bullet Cluster. Calculations show that vacuum perturbations align with collisionless galaxies, reproducing the observed lensing offset (~250 kpc) and effective mass (~2.0 × 10^{14} M_\odot within 250 kpc) using only baryonic mass, matching Chandra X-ray and HST lensing data. DVFT resolves Bullet Cluster observations without exotic matter, offering a physical alternative to CDM while aligning with broader cosmological data.

A q-deformed field theory at finite temperature is presented and its related thermo field dynamics is constructed. This enables us to introduce the quon field, whose Lagrangian leads to a q-deformed partition function. Accordingly, the general thermostatistical properties of a gas model of quon fields, such as the q-deformed statistical distribution function describing an intermediate-statistics behavior and the equation of state in two and three dimensions, are investigated. For low temperatures, the conditions under which Bose–Einstein-like condensation would occur in the quon gas model are discussed. It is shown that the critical temperature of such a gas is higher than that of the usual Bose gas for values of the model parameter q in the range [Formula: see text]. For high temperatures, possible anyonic behavior of the present quon gas model in two spatial dimensions is studied through an analysis of the effect of deformation on the second and third virial coefficients in the equation of state. The results obtained in this work reveal the ability of the model for analyzing a parastatistical behavior of systems with quasiparticles and put forward it as a possible candidate for effectively modeling the properties of some exotic quantum states, such as in the case of dark matter constituents.

Warm and self-interactive dark matter cosmologies have been proposed as nonbaryonic solutions to the tensions between the Λ cold dark matter model and observations at the kiloparsec scale. In this paper, we used the dark matter-only runs of the project, a set of cosmological simulations of different sizes and resolutions, to analyze the macroscopic impact of alternative dark matter models on the abundance, radial distribution, and clustering properties of halos. We adopted the halo occupation distribution formalism to characterize the evolution of its parameters M_1 and α with the mass and redshift selection of our sample. By dividing the halo population into centrals and satellites, we were able to study their spatial density profile. We found that a Navarro-Frenk-White model is not accurate enough to describe the radial distribution of subhalos and that a generalized Navarro-Frenk-White model is required instead. Warm dark matter models, in particular, present a cuspier distribution of satellites, whereas self-interacting dark matter exhibits a shallower density profile. Moreover, we found that the small-scale clustering of dark matter halos provides a powerful tool for distinguishing among alternative dark matter scenarios, in preparation for a more detailed study that fully incorporates baryonic effects and for a comparison with observational data from galaxy clustering. aida-tng

Rising Star: Single cell omics technologies: when whole omics analysis meets single cell resolution.

Caustic crossings in giant arcs with extended dark matter objects

We report an optical dipole trap of strontium monohydroxide (SrOH) with 1400(300) trapped molecules. Through optical pumping, we access vibrational states that are proposed for improved probes of the electron’s electric dipole moment (eEDM) and ultralight dark matter (UDM). For each of these states, the lifetime of trapped molecules is measured and found to be consistent with spontaneous radiative decay and blackbody excitation limits, making this platform viable for these eEDM and UDM searches.

Abstract If dark matter is ultra-light and has certain Standard Model interactions, it can change the mass–radius relation of white dwarf (WD) stars. The coherence length of ultra-light dark matter (ULDM) imparts spatial correlations in deviations from the canonical mass–radius relation, and thus, WDs can be used to reconstruct the coherence length, or equivalently the particle mass, of the dark matter field. We simulate the observability of such spatial correlations accounting for realistic complications like variable hydrogen envelope thickness, dust, binaries, measurement noise, and distance uncertainties in DA WDs. Using a machine learning approach on simulated data, we measure the dark matter field coherence length and find that large deviations from the mass–radius relation (∼10% change in radius) are needed to produce an observable signal given realistic noise sources. We apply our spatial correlation measurement routine to the Sloan Digital Sky Survey catalog of 10,207 DA WDs. We detect a positive spatial correlation among WDs at separations corresponding to a coherence length of 300 ± 50 pc, with an average Z -score of 85 for WDs separated by less than this coherence length. We conclude that this signal is due to observational bias. The signal can be explained by an offset between measurements and theory for nearby cool WDs, and the presence of few, low-temperature WDs with noisy measurements at farther distances. With future improvements in WD models and measurement techniques, particularly for cool WDs, this method can provide interesting constraints on ULDM models.