RAS_WEB

A reassessment of LVE method and hemispherical power asymmetry in CMB temperature data from Planck PR4 Sanjeev Sanyal, Sanjeet K. Patel, Pavan K. Aluri, Arman Shafieloo arXiv:2411.15786v3 Announce Type: replace Abstract: We undertake a reassessment of one of the large angular scale anomalies observed in cosmic microwave background (CMB) temperature signal referred to as Hemispherical Power Asymmetry (HPA). For the present analysis we use texttt{SEVEM} cleaned CMB maps from emph{Planck}’s 2020 final data release (public release 4/PR4). To probe HPA, we employed the local variance estimator (LVE) method with different disc radii ranging from $0.5^circ$ to $90^circ$. Our emphasis here is to revalidate the LVERead More →

Description of 4 Spacecraft, Moving on Elliptic Kepler Orbits Vladimir P. Zhukov, Nikolai K. Iakovlev, Alexander A. Bochkarev, Nikita E. Logvinenko, Sergei M. Kurchev, Vlas A. Karavaikin, Ivan A. Radko arXiv:2602.13604v1 Announce Type: cross Abstract: The four-spacecraft formation is essential for measurements of various physical fields. The use of this formation on substantially elliptical heliocentric Kepler orbits allows measuring gradients of gravitation field in Solar system. The accuracy of the measurements will be sufficient to confirm or to refute modified theories of gravity. In this paper a new approach for the description of this formation is presented. The analytical solutions of the linearized motion equationsRead More →

Local Short-Time Acceleration and deSitter Spacetime induced Extra Spectral Broadening: a Simple Interpretation of Modified Inertial in MOND M. J. Luo arXiv:2602.14515v1 Announce Type: cross Abstract: This paper proposes a novel quantum effect wherein particle spectra show extra broadening due to local short-time acceleration (as well as in a deSitter spacetime background). This effect provides a simple interpretation for the acceleration interpolation relation required to modify the kinematics of a test particle in the Modified Inertial interpretation of Modified Newtonian Dynamics (MOND). This effect can be regarded as a generalization of the thermal blackbody spectrum generated by the Unruh effect (which arises from long-time uniformRead More →

Two late-T dwarfs at kiloparsec distances revealed by JWST UNCOVER survey D. H. Li, Z. H. Zhang, H. H. Peng, M. C. Galvez-Ortiz, S. Y. Zhou, H. R. A. Jones arXiv:2602.01894v2 Announce Type: replace Abstract: We conducted a search for brown dwarf candidates in a James Webb Space Telescope deep field around A2744 to investigate the space density of these objects at kiloparsec distances. Our methodology employed an initial selection based on photometric colours, followed by spectral energy distribution fitting to both stellar atmospheric models and high-redshift galaxy templates. This approach yielded two robust T dwarf candidates and one possible L subdwarf candidate. The TRead More →

GAMERA-OP: A three-dimensional finite-volume MHD solver for orthogonal curvilinear geometries Hongyang Luo, Binzheng Zhang, Jiaxing Tian, Jinshu Cai, Junjie Chen, Enhao Feng, Zhiqi Zheng, Sheng Xi, John G. Lyon arXiv:2602.12307v1 Announce Type: new Abstract: We present GAMERA-OP (Orthogonal-Plus), a three-dimensional finite-volume magnetohydrodynamics (MHD) solver for orthogonal curvilinear geometries. The solver advances magnetic fields using constrained transport to preserve $nabla!cdot!mathbf{B}=0$ to machine precision and employs geometry-consistent high-order reconstruction with an enhanced Partial Donor Cell method (e-PDM) that accounts for geometry curvature. Flexible numerics include various numerical fluxes and time integrators. In axial symmetric coordinates, angular momentum are preserved to round-off, and a ring-averaging treatment near theRead More →

Nucleus and Postperihelion Activity of Interstellar Object 3I/ATLAS Observed by Hubble Space Telescope Man-To Hui, David Jewitt, Max J. Mutchler, Jessica Agarwal, Yoonyoung Kim arXiv:2601.21569v2 Announce Type: replace Abstract: We report the detection of the nucleus of interstellar object 3I/ATLAS, using a nucleus extraction technique on Hubble Space Telescope (HST) observations taken between December 2025 and January 2026. The product of the V-band geometric albedo, $p_V$, with the physical cross-section of the nucleus is $0.22 pm 0.07$ km$^{2}$, which corresponds to an effective radius of $1.3 pm 0.2$ km if assuming a comet-like albedo $p_{V} = 0.04$. This size is in agreement with an independentRead More →

Trace anomaly contributions to semi-classical wormhole geometries Mohammad Reza Mehdizadeh, Amir Hadi Ziaie, Francisco S. N. Lobo arXiv:2509.04049v2 Announce Type: replace-cross Abstract: We investigate wormhole solutions within the framework of the semi-classical Einstein equations in the presence of the conformal anomaly (or trace anomaly). These solutions are sourced by a stress-energy tensor (SET) derived from the trace anomaly, and depend on two positive coefficients, $alpha$ and $lambda$, determined by the matter content of the theory and on the degrees of freedom of the involved quantum fields. For a Type B anomaly ($alpha=0$), we obtain wormhole geometries assuming a constant redshift function and show that theRead More →

The JWST EXCELS survey: Insights into the nature of quenching at cosmic noon Maya Skarbinski, Kate Rowlands, Katherine Alatalo, Vivienne Wild, Adam C. Carnall, Omar Almaini, David Maltby, Thomas de Lisle, Timothy Heckman, Ryan Begley, Fergus Cullen, James S. Dunlop, Guillaume Hewitt, Ho-Hin Leung, Derek McLeod, Ross McLure, Justin Atsushi Otter, Pallavi Patil, Andreea Petric, Alice E. Shapley, Struan Stevenson, Elizabeth Taylor arXiv:2509.18278v2 Announce Type: replace Abstract: We study 24 massive quiescent galaxies with $log textrm{M}_*/textrm{M}_odot > 10$ at $1 10.7$) exhibiting shorter visibility times than lower mass galaxies. The range of quenching times — defined as the time from the peak starburst to theRead More →

A redshift-independent theoretical halo mass function validated with Uchuu simulations Elena Fern’andez-Garc’ia, Juan E. Betancort-Rijo, Francisco Prada, Tomoaki Ishiyama, Anatoly Klypin, Jos’e Ruedas arXiv:2512.05847v2 Announce Type: replace Abstract: We present a new theoretical framework for the halo mass function (HMF) that accurately predicts the abundance of dark matter haloes across an exceptionally wide range in mass and redshift. Building on a generalised Press & Schechter model and triaxial collapse (GPS+), we predict the HMF in terms of the variance of the linear density field, with only a weak explicit dependence on halo mass and no explicit dependence on redshift. The GPS+ model naturally provides theRead More →

Big Bang Nucleosynthesis and the Neutrino-Extended Standard Model Effective Field Theory Pieter Braat, Jordy de Vries, Jelle Groot, Julian Y. G"unther, Juraj Klari’c arXiv:2602.12745v1 Announce Type: cross Abstract: We study the impact of light GeV-scale heavy neutral leptons (HNLs) on Big Bang nucleosynthesis (BBN) in the neutrino-extended Standard Model Effective Field Theory ($nu$SMEFT). We show that, based on very general considerations, BBN constraints complement laboratory searches at colliders, beam dumps, and neutrinoless double beta decay, by providing an upper bound on the cut-off scale of the effective field theory for HNL masses above $sim$100 MeV. We identify target regions for future laboratory probes of theRead More →

CMB line-of-sight integrators for nearly-isotropic cosmological models Jo~ao G. Vicente, Thiago S. Pereira, Cyril Pitrou arXiv:2506.07786v2 Announce Type: replace Abstract: Homogeneous and nearly-isotropic cosmological models are natural extensions of standard Friedmann cosmologies. Constraining their features is crucial, as any detection of their properties would impact our understanding of inflation and the cosmological principle. Since these models evolve as a set of non-interacting scalar, vector, and tensor modes on top of homogeneous and isotropic spacetimes, their imprints on cosmological observables, particularly the CMB, can be obtained using standard line-of-sight methods. This requires (1) that one resorts on Laplacian eigenmodes on spatially curved spaces and (2) thatRead More →

A tight relation between the distribution of globular clusters and dark matter in AS1063 J. M. Diego, C. Goolsby, C. J. Conselice, J. M. Palencia arXiv:2602.12332v1 Announce Type: new Abstract: Based on deep high resolution JWST images of AS1063, and after a careful masking of artifacts, extended features in the cluster, and background galaxies (including known lensed ones), we have identified tens of thousands of unresolved point sources in the central region of the galaxy cluster. We extended the identification of these point sources up to 1.18 Mpc from the center of the cluster using data in the second module. Most of these sources areRead More →

An analytic approximation to the covariance between pre- and post-reconstruction galaxy two-point statistics M. Maus, A. Baleato Lizancos, M. White, A. de Mattia, S. Chen arXiv:2602.12343v1 Announce Type: new Abstract: We present a simple analytic approximation for the covariance between pre-reconstruction galaxy power spectrum measurements and post-reconstruction two-point correlation functions. This cross-covariance is essential for joint analyses that combine full-shape clustering information with baryon acoustic oscillation (BAO) measurements, as commonly performed in modern spectroscopic surveys. Our model builds on the disconnected contribution to the covariance and accounts for the damping of correlations due to the BAO reconstruction process. We validate our analytic prescription against numericalRead More →

A boost in the precision of cluster-mass models: Exploiting the extended surface brightness of the lensed supernova Refsdal host galaxy S. Schuldt, C. Grillo, A. Acebron, P. Bergamini, A. Mercurio, P. Rosati, S. H. Suyu arXiv:2602.12329v1 Announce Type: new Abstract: Combining deep Hubble Space Telescope (HST) images and extensive data from the Multi-Unit Spectroscopic Explorer, we present new mass models of the cluster MACS J1149.5+2223, strongly lensing the supernova (SN) Refsdal, fully exploiting the source surface-brightness distribution of the SN host for the first time. In detail, we incorporated 77,000 HST pixels, in addition to the known 106 point-like multiple images, in our modeling. WeRead More →