RAS_WEB (Page 5)

Comparing Hemispheres: Anisotropy in the deceleration parameter $q_0$ Mauricio Lopez-Hernandez, Josue De-Santiago arXiv:2605.03004v1 Announce Type: new Abstract: We present a hemispherical comparison analysis of the deceleration parameter $q_0$ using the Pantheon+ sample of Type Ia supernovae to test the isotropy of cosmic acceleration and the robustness of redshift corrections. We detect directional variations in $q_0$ across redshift frames. Even in the $z_{mathrm{HD}}$ frame, where corrections for the CMB dipole and peculiar velocities are applied, a residual dipolar anisotropy persists with $Delta q_0 = 0.112$ and a maximum signal to noise $S/N = 2.155$, aligned with the CMB dipole direction and decreasing with increasing minimum redshiftRead More →

Are Nucleosynthetic Yields Universal? Interpreting the Multi-Elemental Abundances of Quiescent Galaxies over Cosmic Time Using Milky Way Stars Aliza G. Beverage, David H. Weinberg, Mariska Kriek, Nicole Marcelina Gountanis, Andrew B. Newman, Daniel R. Weisz arXiv:2605.03000v1 Announce Type: new Abstract: The detailed abundance patterns of quiescent galaxies offer powerful constraints on their formation and evolution. Yet physical insight remains elusive, as nucleosynthetic yields are notoriously uncertain. We introduce a framework that circumvents this problem by using Milky Way abundance trends as empirical proxies for the yields. Applied to quiescent galaxies spanning three redshifts, SDSS ($zsim0$), LEGA-C ($zsim0.7$), and JWST/SUSPENSE ($zsim2$), our approach recovers the $alpha$-Read More →

Environmental Quenching of High-Redshift Galaxies: Interpreting JWST Observations with Simulations Aleyna D"oven, Mohammadreza Ayromlou, Cristiano Porciani arXiv:2605.03008v1 Announce Type: new Abstract: Recent observations of the high-redshift Universe, particularly with JWST, have revealed a population of quenched galaxies that challenges current galaxy formation models, which systematically underpredict their abundance. This discrepancy has been extensively studied for massive systems, motivating revisions to internal quenching mechanisms such as AGN feedback. However, the origin of quenching in lower-mass galaxies at high-z has received far less attention, largely due to previous observational limitations. JWST has now identified low-mass quenched galaxies (${M_{star}}3$. We analyze several simulations, including L-GALAXIES, IllustrisTNG, SIMBA, andRead More →

Post-Recombination Fluctuations from a Sequestered Dark Sector Salvatore Bottaro, Michael Geller, Diego Redigolo, Maya Tsur arXiv:2605.03007v1 Announce Type: new Abstract: We develop a formalism to characterize the imprints of late-time sources of cosmological fluctuations under the sole assumption that the injection occurs on timescales short compared to the horizon. For post-recombination injections, we derive the general modification of photon geodesics in the presence of scalar, vector, and tensor perturbations, and compute the resulting impact on the Cosmic Microwave Background through the integrated Sachs-Wolfe effect. We show that the signal is generically dominated by instantaneous injections of anisotropic stress. As an application, we consider first-order phaseRead More →

Placing the Near-Earth Object Impact Probability in Context C. R. Nugent, K. P. Andersen, James M. Bauer, C. T. Jensen, L. K. Kristiansen, C. P. Hansen, M. M. Nielsen, C. F. Vesterg{aa}rd arXiv:2508.02418v3 Announce Type: replace Abstract: Near-Earth objects (NEOs) have the potential to cause extensive damage and loss of life on Earth. Advancements in NEO discovery, trajectory prediction, and deflection technology indicate that an impact could be prevented, with sufficient warning time. We derive an impact frequency of NEOs 140m and larger, using the NEOMOD2 NEO population model and JPL Horizons. We then place that frequency in context with other preventable causes of death;Read More →

Self-Interaction Bounds on Ultralight Dark Matter Couplings to Matter Mohammad Aghaie, Shao-Ping Li arXiv:2605.03477v1 Announce Type: cross Abstract: Ultralight dark matter (ULDM) couplings to matter fields and ULDM self-interactions are typically treated as independent probes. However, since the ULDM-matter couplings unavoidably induce self-interactions through quantum loop corrections, bounds on self-interacting ULDM from astrophysical and cosmological observations will also limit the coupling strength to matter. Applying this argument, we find that self-interaction bounds can impose strong constraints on the linear ULDM couplings to neutrinos, excluding a large portion of parameter space that is widely considered for probing ULDM via neutrino oscillation experiments. In addition, the self-interactionRead More →

ULTIMATE deblending I. A 50-band UV-to-MIR photometric catalog combining space- and ground-based data in the JWST/PRIMER survey Hanwen Sun, Tao Wang, Ke Xu, David Elbaz, Emiliano Merlin, Cheng Cheng, Emanuele Daddi, Shuowen Jin, Wei-hao Wang, Longyue Chen, Adriano Fontana, Zhen-Kai Gao, Jiasheng Huang, Benjamin Magnelli, Valentina Sangalli, Yijun Wang, Tiancheng Yang, Yuheng Zhang, Luwenjia Zhou arXiv:2603.05289v2 Announce Type: replace Abstract: Our understanding of the early Universe has long been limited by biased galaxy samples selected through various color criteria. With deep JWST infrared imaging, mass-complete galaxy samples can now be studied up to $z sim 8$ for the first time. However, recent work has revealedRead More →

Comparing cosmic shear nulling methods for Stage-IV surveys Naomi Clare Robertson, Alex Hall arXiv:2512.15604v2 Announce Type: replace Abstract: We present an analysis comparing nulling strategies for reducing the impact of baryon feedback on cosmic shear measurements. We consider three different approaches which aim to `null’ the high-$k$ modes using transformations applied to the data vector: the Bernardeau-Nishimichi-Taruya (BNT) transform which operates on the lensing field, a new implementation of an LU factorisation of the discretized Limber integral (LUnul) which operates on the lensing two-point statistics, and finally a method which uses a correlated LSS tracers to suppress contributions from lower redshifts (cross-correlation). We compare theseRead More →

Signatures of a subpopulation of hierarchical mergers in the GWTC-4 gravitational-wave dataset Cailin Plunkett, Thomas Callister, Michael Zevin, Salvatore Vitale arXiv:2601.07908v2 Announce Type: replace-cross Abstract: Repeated black-hole mergers in dense stellar clusters are a plausible mechanism to populate the predicted gap in black hole masses due to the pair-instability supernova process. These hierarchical mergers carry distinct spin characteristics relative to first-generation black holes. We introduce an astrophysically motivated model in the joint space of effective inspiral and precessing spins, which captures the dominant spin dynamics expected for hierarchical mergers. We find decisive evidence for a transition at $m_1 = 46.2_{-7.2}^{+12.6} M_odot$, above which the populationRead More →

Differentiable Forward Modeling for Efficient and Accurate Shear Inference Ismael Mendoza, Axel Guinot, Matthew R. Becker, Camille Avestruz, Jean-Eric Campagne, Natalia Porqueres, Michael Schneider, Eleni Tsaprazi, the LSST Dark Energy Science Collaboration arXiv:2604.22048v2 Announce Type: replace Abstract: Forthcoming Stage-IV dark energy optical surveys, such as LSST, have the ambitious goal of measuring cosmological parameters at sub-percent precision. Realizing their full scientific potential requires very precise measurement of the cosmic shear signal and control of corresponding systematics. In this work, we present a modern implementation of the Bayesian shear inference framework in Schneider et al. (2014), in the case that the PSF and sky background areRead More →

The jet-shaped pipe morphology in planetary nebulae and core-collapse supernova remnants Noam Soker (Technion, Israel), Jessica Braudo (Technion, Israel) arXiv:2605.03961v1 Announce Type: new Abstract: We compare images of core-collapse supernova (CCSN) remnants (CCSNRs) and jet-shaped planetary nebulae (PNe) that have a narrow, faint zone extending from side to side, termed a pipe, with a hydrodynamical numerical simulation exploding a massive star with three pairs of jets in the framework of the jittering jets explosion mechanism (JJEM), and conclude that jets shaped the pipes in these CCSNRs and PNe. We present two jet-shaped PNe with a pipe and three PNe with two opposite narrow jet-shaped lobes,Read More →

A Statistical Survey of Faint Solar X-ray Transients Observed by NuSTAR Reed B. Masek (University of Minnesota), Lindsay Glesener (University of Minnesota), Jessie Duncan (NASA Marshall Space Flight Center), Kekoa Lasko (University of Minnesota), Nat’alia Bajnokov’a (University of Glasgow), Mary Davenport (Epic Systems), Marianne Peterson (University of Minnesota), Ian Markano (University of Minnesota), Zasha Avery (University of Minnesota), Kristopher Cooper (University of Minnesota), Iain G. Hannah (University of Glasgow), Brian W. Grefenstette (California Institute of Technology), Stephen M. White (Air Force Research Laboratory), Hugh Hudson (University of Glasgow), S"am Krucker (University of Applied Sciences and Arts Northern Switzerland, University of California, Berkeley), David M. SmithRead More →

Estimating the triaxiality of massive clusters from 2D observables in MillenniumTNG with machine learning Ana Maria Delgado, Michelle Ntampaka, Sownak Bose, Fulvio Ferlito, Boryana Hadzhiyska, Lars Hernquist, John Soltis, John F. Wu, Mikaeel Yunus, John ZuHone arXiv:2511.20429v2 Announce Type: replace Abstract: Properties of massive galaxy clusters, such as mass abundance and concentration, are sensitive to cosmology, making cluster statistics a powerful tool for cosmological studies. However, favoring a more simplified, spherically symmetric model for galaxy clusters can lead to biases in the estimates of cluster properties. In this work, we present a deep-learning approach for estimating the triaxiality and orientations of massive galaxy clusters (thoseRead More →

Foundations for Discovery: A Coordinated Fleet Approach to NASA Astrophysics Regina Caputo, Francesca M. Civano, Knicole D. Col’on, Brian Humensky, David T. Leisawitz, Avi M. Mandell, Conor A. Nixon, Georgia A. de Nolfo, Jeremy S. Perkins, Elisa V. Quintana, Judith L. Racusin, Joshua E. Schlieder, Albert Y. Shih, Amy A. Simon, Jacob Slutsky, Tonia M. Venters, Jennifer J. Wiseman, Allison A. Youngblood arXiv:2605.02880v1 Announce Type: new Abstract: This white paper presents an analysis of Astro2020 science priorities and NASA’s future astrophysics mission architecture, advocating for a coordinated fleet of $1–2B missions, smaller than typical Flagship observatories, but strategically designed to complement them, i.e. a “NextRead More →

Prospects for Observing Galaxy Spectral Energy Distribution from the Radio to the far-Infrared in the Era of Next-Generation Radio Telescopes Ilsang Yoon, Jonathan Letai, Hansung B. Gim, Eric F. Jim’enez-Andrade, Intae Jung, Caitlin Casey, Eric J. Murphy, Min S. Yun arXiv:2605.01000v1 Announce Type: new Abstract: The superb sensitivity and angular resolution of the next-generation radio telescopes with combined frequency coverage of approximately over three orders of magnitude (100 MHz–100 GHz) will sample the radio and far-infrared (FIR) spectral energy distribution (SED) of galaxies and revolutionize the galaxy formation study at the epoch of re-ionization and beyond. We present a prospect of observing the radio–FIR continuumRead More →