We develop a thermodynamic formulation of the specific RHt=ct cosmological framework presented here in which the CMB temperature, the Planck temperature, and a horizon Hawking-temperature scale provide direct expressions for a broad set of cosmological quantities. Our preferred geometrical realization identifies the Hubble boundary with the event horizon of the neutral Haug–Spavieri (HS) minimal solution, whose lapse function is algebraically equivalent to that of an extremal Reissner–Nordström horizon but admits a charge-free interpretation. With RHt=GMt/c2 and the conjectured growth law dMt/dt=mp/tp=c3/G, the horizon evolves as RHt=ct. Although the conventional net Hawking flux of an extremal horizon vanishes, the Carnot-universe interpretation retains counteracting outward and inward thermodynamic channels whose signed fluxes cancel externally; their Hawking-temperature magnitude remains relevant to the geometric-mean relation Tcmb,t=TmaxTmin,t. In the HS branch, this relation gives the standard temperature scaling when the proposed redshift mapping 1+z=Ht/H0 is adopted; establishing that mapping observationally requires its derivation from photon propagation in the completed dynamical metric. We also formulate a conservative FLRW/apparent-horizon alternative, in which RA,t=c/Ht=2ct during a radiation-type phase and the same temperature scaling follows from 1+z=a0/a. In natural units, the background relations reduce to a compact one-scale description through the reduced Compton wavelength of the horizon mass. The framework provides a direct and testable connection between horizon thermodynamics, the CMB temperature, and the principal cosmological scales.
We investigate the implications of interactions between ultralight dark matter (ULDM) and Standard Model fermions for the radiative stability of the ULDM potential. By matching the heavy fermion onto a low-energy scalar effective field theory, we derive the one-loop threshold corrections to the ULDM mass and self-interaction couplings. We interpret these corrections in terms of radiative naturalness conditions defined within the threshold-matching prescription adopted here. For the parameter region motivated by cosmological and galactic considerations, the quadratic correction provides the strongest naturalness criterion. The precise numerical contour associated with this criterion is prescription-dependent. Nevertheless, the calculation exhibits the generic sensitivity of an unprotected ultralight scalar mass to the heavy-fermion scale. For the benchmark boundary condition aR(mf)=0 and for Yukawa couplings satisfying the scalar-mass naturalness criterion, both the direct and cubic-induced quartic corrections remain subdominant relative to the cosmologically required quartic coupling.
I investigate whether one minimally coupled canonical scalar field can generate, in a single continuous cosmological history, the correlated changes in the sound horizon, late-time expansion, and structure growth that are relevant to the H0, evolving dark-energy, and S8 tensions. The potential consists of a localized positive feature on an exponential tail. In contrast with a purely qualitative treatment, I derive the exact first and second derivatives of the complete potential, determine their extremum without invoking a bump-dominated approximation, and evolve the full scalar equations numerically from the pre-recombination era to the present. A calibrated benchmark has a transient scalar fraction, Ωϕ,pk=0.151, at zpk≃3.50×103, gives rd=141.1Mpc with H0=70.0kms−1Mpc−1, and evolves to (w0,wa)=(−0.844,−0.176) when the exact numerical wϕ(a) is locally compressed into the CPL basis. Using the DESI DR2-compressed BAO measurements with their reported uncertainties and within-pair correlations, this full benchmark gives χBAO2=9.48 for 13 BAO observables. Profiling the exact late-time scalar background over the tail slope gives λbf=1.00 and an approximate 68% profile interval, 0.51<λ<1.26, with χBAO2=8.78 compared with 10.55 for the λ=0 limit. Solving the GR growth equation on the same scalar background, with the same high-redshift normalization, yields S8=0.794, in agreement with the DES Year-6 cosmic-shear value. I also formulate the canonical scalar perturbation equations and explicitly show that the model is ghost-free and has rest-frame sound speed, cs2=1; the short hilltop release is a finite tachyonic-curvature episode rather than a ghost or gradient instability. These results establish a quantitatively calibrated one-field mechanism that moves the three relevant observables in the required correlated directions and makes concrete predictions that can be subjected to a full CMB-spectrum likelihood analysis.
Subauroral geospace is a dynamic region. Its various features include Subauroral Polarization Streams (SAPS), hot and cold zones, and storm enhanced densities (SED). Previous studies have covered the nightside, leaving the dayside largely unexplored and poorly understood. This study investigates the prenoon and midday sectors, based on multi-instrument, multipoint observations. In the inner magnetosphere, the observed dayside SAPS’ development was set off by solar-wind flow pressure increases compressing the dayside magnetosphere in the equatorial plane and triggering earthward-directed hot plasma surges or particle injections in the coupled Alfvenic solar wind and dayside magnetosphere. The dayside SAPS developed in an inner-magnetosphere voltage generator and appeared sometimes within the cold zone where the isotropic ion temperature (Ti‖ ≈ Ti⊥) minimized and sometimes within the hot zone fueled by whistler-mode chorus waves locally enhancing the field-aligned temperature anisotropy (T‖ > T⊥) and providing localized plasma heating both via Landau damping and implicitly. In the ionosphere, the observed dayside SAPS’ development was unfolding in a prenoon eastward auroral electrojet (AEJ) scenario on the dawnside and in a midday westward AEJ scenario on the duskside. The observed dayside SAPS mapped down to the noontime SED plume base depicted by the total electron content maps.
We present new results of the investigation of the optical spectrum features of the central star with the B[e] phenomenon in the system of the IR-source IRAS 01005+7910 using high-resolution (R≥ 60,000) spectroscopy data taken by the 6 m BTA telescope with the NES spectrograph. Comparison of the spectra obtained at different times shows significant variations in the complex Hα and Hβ line profiles, such as a systematic increase in their emission peak strengths in 2025–2026 compared to those observed in 2013 as well as a strong variability in their wind component. A detected variable radial velocity V⊙ from −20 to −68 km s−1 with a standard deviation of the mean value of K = 8.0 km s−1 can be interpreted as a result of pulsations or the presence of a companion. The stationary positions of forbidden lines with a mean radial velocity of V⊙=−51.38±0.26 km s−1 are taken as an improved systemic velocity. Overall, a set of properties of IRAS 01005+7910 points to its status as a post-AGB star, which has undergone the hot-bottom burning phase.
