What is happening in dark matter, cosmology and astrophysics

D. Gilman, A.M. Nierenberg, T. Treu et al. · Phys.Rev.Lett. 137 (2026) 081004

Using 28 quadruple-image strong gravitational lenses observed by JWST, this study measures halo properties to constrain the free-streaming length of dark matter, a quantity tied to the particle's mass and production mechanism. By simultaneously reconstructing extended lensed arcs together with image positions and magnifications, the analysis improves sensitivity to small perturbing halos and rules out deviations from cold-dark-matter predictions on the smallest scales probed, of direct interest to anyone testing warm or other non-cold dark-matter scenarios.

arXiv · INSPIRE · DOI

Yi-Wen Wu, Jun-Qing Xia · Phys.Rev.D 114 (2026) 043544

This paper measures the Solar System's kinematic dipole using a redshift-dipole method applied to DESI DR1, testing the 'cosmic dipole tension' between the velocity inferred from the CMB dipole and that inferred from large-scale-structure number counts. The redshift-dipole estimator is less sensitive to imaging systematics and selection-function uncertainties than traditional number-count measurements, offering a cleaner test of the cosmological principle.

arXiv · INSPIRE · DOI

Shangyun Wang, Shengjia Wang · Eur.Phys.J.C 86 (2026) 930

Motivated by DESI DR2's geometrical preference for departures from ΛCDM, this paper asks whether the same late-time distance data could instead be absorbed by a redshift-dependent effective speed of light, parametrised by a single extra parameter. Using only late-time data, the analysis offers an alternative, non-dark-energy reading of the DESI anomaly.

INSPIRE · DOI

Lei Ming, Marco Drewes · Phys.Rev.D 114 (2026) 063534

Anticipating a future detection of primordial gravitational waves, this study forecasts what an expanded Simons Observatory - growing to six small-aperture telescopes by 2027 - could learn about cosmic reheating, for benchmark tensor-to-scalar ratios of r=0.0036 or r=0.01. In plateau inflation models such a detection would fix the inflationary scale and let the reheating temperature and inflaton couplings be pinned down.

arXiv · INSPIRE · DOI

Lionel Maurin, François Gautier, Maël Brun et al. · Phys.Rev.D 114 (2026) 042002

This paper models the Newtonian (gravity-gradient) noise of acoustic origin in the Virgo gravitational-wave detector, one of the vibroacoustic noise sources limiting sensitivity at low frequency. Understanding and mitigating this noise matters for current detector upgrades and for the design of next-generation instruments such as the Einstein Telescope and Cosmic Explorer.

arXiv · INSPIRE · DOI

Jie Zheng, Da-Chun Qiang, Zhi-Qiang You et al. · Eur.Phys.J.C 86 (2026) 924

Using DESI BAO DR2 together with Pantheon+ supernovae and Planck CMB distance priors, this analysis examines the w0waCDM model with two complementary redshift-cut strategies to see which part of the data drives the apparent preference for dynamical dark energy over ΛCDM. The authors find the most noticeable shifts occur when BAO and supernova data around z~0.4-0.8 are included, helping to localise the origin of the DESI dark-energy anomaly.

arXiv · INSPIRE · DOI