Tag: Cosmology
Interacting dark energy and dark matter models fit current data
What the study found The study found that two versions of a cosmological model with interacting dark energy and dark matter can fit current observations well. The models use a Gauss–Bonnet-coupled scalar field as dark energy and a fermionic dark matter field, with either an exponential or a power-law scalar potential. Why the authors say…
Cluster stellar mass growth is mostly established by redshift 0.8
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in AstronomyWhat the study found The study found that, in a sample of massive galaxy clusters, the characteristic stellar mass in the cluster stellar mass function evolves only slightly from redshift 0.8 to 0.55, and that most measurable growth happens between redshift 0.55 and 0.2. The authors also report evidence that the stellar mass fraction in…
Particle creation model explains cosmic expansion without dark energy
What the study found A dark-energy-free cosmological model based on gravitationally induced adiabatic particle creation is proposed. The authors report that it can reproduce a Lambda CDM-like expansion for suitable values of its parameters and that it evolves smoothly between two de Sitter phases. Why the authors say this matters The authors conclude that the…
Higher-order statistics improve constraints on reionization history
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in AstrophysicsWhat the study found Betti numbers, a non-Gaussian statistic that captures topological features, were on average more informative than the power spectra for constraining the average neutral hydrogen fraction. The bispectrum was described as providing limited constraints, but combining higher-order statistics with the cylindrical power spectrum improved the mean figure of merit. Why the authors…
Starobinsky model remains viable in parts of parameter space
What the study found The authors report that, despite recent data placing pressure on the pure Starobinsky inflation model, there is still a significant region of parameter space where the model remains highly consistent with the latest observations. They also say that adding a cubic $R^3$ term can shift the model's predictions toward better agreement…
Non-Gaussian redshift-space Minkowski tensors show qualified perturbation-theory success
What the study found The study found that perturbation-theory predictions for Minkowski tensors in redshift space are a qualified success when compared with dark matter simulation measurements. It also found that nonperturbative Finger-of-God effects remain significant at relatively large scales, especially in components parallel to the line of sight. Why the authors say this matters…
Dark decay channels strengthen cosmological bounds on heavy neutral leptons
Cosmological analysis shows heavy neutral leptons with dark decay modes face stronger big bang nucleosynthesis constraints, not weaker ones, narrowing viable parameter space for terrestrial detection.
Deep Chandra observations of a relaxed z = 1.16 galaxy cluster
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in AstrophysicsChandra X-ray observations of SPT-CL J2215-3537 resolve the cool core of this z = 1.16 relaxed galaxy cluster, establishing a high-redshift benchmark for cluster evolution studies.
