RAS_WEB (Page 6)

Observations of Atmospheric Helium and Oxygen with SPHEREx Howard Hui, Chi Nguyen, Ryan Wills, Katrina Bossert, Sean Bryan, Yoonsoo Bach, Jamie Bock, Tzu-Ching Chang, Shuang-Shuang Chen, Asantha Cooray, Brendan Crill, Olivier Dor’e, C. Darren Dowell, Andreas Faisst, Jae Hwan Kang, Phil Korngut, Carey Lisse, Dan Masters, Roberta Paladini, Volker Tolls, Michael Werner, Yujin Yang, Mike Zemcov arXiv:2605.00851v1 Announce Type: cross Abstract: We present measurements of near-infrared (NIR) terrestrial airglow produced by helium and oxygen in the exosphere as observed by SPHEREx. Using eight months of survey data obtained from a 680 km low-Earth orbit, emission from HeI $lambda$10830, OI $lambda$8446, and OI $lambda$11287 is mappedRead 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 →

NASA Exoplanet Exploration Program (ExEP) Science Gap List Karl Stapelfeldt, Eric Mamajek arXiv:2507.18665v2 Announce Type: replace Abstract: The Exoplanet Exploration Program (ExEP) is chartered by the NASA Astrophysics Division to carry out science, research, and technology tasks that advance NASA’s science goals for exoplanets. The ExEP Science Gap List is a compilation of “science gaps”, defined as either: 1) The difference between knowledge needed to define requirements for specified future NASA exoplanet missions and the current state of the art, or 2) Knowledge which is needed to enhance the exoplanet science return of current and future NASA exoplanet missions. It is annually updated and inputRead More →

Formation and Redshift Evolution of Dark Matter Spikes Gonzalo Herrera, Abdelaziz Hussein, Lina Necib, Elliot Y. Davies, Xuejian Shen arXiv:2605.01023v1 Announce Type: new Abstract: Dark matter density spikes forming around adiabatically growing black holes can dramatically enhance indirect and direct detection signals. Canonical predictions, however, assume a zero-mass seed in a purely dark matter environment and do not track the long-term dynamical impact of surrounding stars. We present a semi-analytic framework that first generalizes adiabatic spike formation to include finite seed masses, stellar cusps, and non-circular orbits, and then studies the subsequent cosmic evolution by solving coupled Fokker-Planck equations for the dark matter and stellarRead More →

First Statistical Study of Over 100 Magnified Stellar Events at Redshift $z approx 0.725$ with JWST J. M. Palencia, Fengwu Sun, J. M. Diego, Yoshinobu Fudamoto, Anton M. Koekemoer, Christopher N. A. Willmer, Eduardo Iani, Xiaojing Lin, Justin D. R. Pierel, Alfred Amruth, Tom Broadhurst, W. Chen, Liang Dai, Daniel Espada, Alexei V. Filippenko, Seiji Fujimoto, Patrick L. Kelly, Mingyu Li, Sung Kei Li, Ashish Kumar Meena, Jordi Miralda-Escud’e, P. Morilla, Mitchell F. Struble, Hayley Williams, Rogier A. Windhorst, E. Zackrisson, Ruwen Zhou, Adi Zitrin arXiv:2604.22702v4 Announce Type: replace Abstract: Highly magnified stars at cosmological distances ($z gtrsim 0.7$) become detectable thanks to microlensing byRead More →

Millimeter-wave Detections of Symbiotic Stars in SPT and ACT Data C. Tandoi, A. Foster, T. J. Maccarone, A. J. Anderson, B. Ansarinejad, M. Archipley, L. Balkenhol, D. R. Barron, K. Benabed, A. N. Bender, B. A. Benson, F. Bianchini, L. E. Bleem, S. Bocquet, F. R. Bouchet, E. Camphuis, M. G. Campitiello, J. E. Carlstrom, J. Carron, C. L. Chang, P. M. Chichura, A. Chokshi, T. -L. Chou, A. Coerver, T. M. Crawford, C. Daley, T. de Haan, K. R. Dibert, M. A. Dobbs, M. Doohan, D. Dutcher, C. Feng, K. R. Ferguson, N. C. Ferree, K. Fichman, S. Galli, A. E. Gambrel, A. K.Read More →

Neural Posterior Estimation for UHECR source inference from 3D propagation simulations Nadine Bourriche, Francesca Capel, Nicole Hartmann arXiv:2605.01004v1 Announce Type: new Abstract: The identification of ultra-high energy cosmic ray sources is one of the open challenges of high-energy astrophysics. As charged particles travel through the Universe, they are deflected by extragalactic magnetic fields and lose energy through interactions with background radiation, making source inference highly non-trivial. Existing approaches either rely on simplified propagation models or on computationally prohibitive Monte Carlo methods. Here we present a simulation-based inference framework trained on three-dimensional texttt{CRPropa~3} propagation simulations that produces calibrated posterior distributions over source energy, distance, direction, andRead 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 →

Optical activity, orbital modulation, and broadband SED constraints for RX J1553.0+4457 S. -Y. Wu, M. Gritsevich, Q. -H. Lao, A. J. Castro-Tirado, Y. -D. Hu, I. P’erez-Garc’ia, R. S’anchez-Ram’irez, E. J. Fern’andez-Garc’ia, M. D. Caballero-Garc’ia, S. Guziy, I. Olivares, J. D. Sakowska, G. Garc’ia-Segura, D. Hiriart, W. H. Lee, P. J. Meintjes, H. J. van Heerden, A. Mart’in-Carrillo, L. Hanlon, A. Maury, L. Hern’andez-Garc’ia, I. M. Carrasco-Garc’ia, S. Castillo-Carri’on, A. Castell’on, N. Castro-Segura, S. B. Pandey, C. J. P’erez del Pulgar, A. J. Reina, J. -M. Bai, Y. -F. Fan, B. Wang, C. -J. Wang, Y. -X. Xin, D. -R. Xiong, X. -H. Zhao, J.Read More →

The complex history of NGC 1427A revealed by its star clusters and star formation history Katja Fahrion, Michael Hilker, Avinash Chaturvedi, Juan P. Carvajal, Thomas H. Puzia arXiv:2605.00993v1 Announce Type: new Abstract: Star-forming low-mass galaxies in the dense environments of galaxy clusters provide opportunities to study how environmental effects such as ram-pressure stripping, tidal interactions, or galaxy mergers shape a galaxy’s star formation history. We combined integral-field spectroscopic observations with the Multi Unit Spectroscopic Explorer (MUSE) and available multi-band imaging of the star-forming galaxy NGC 1427A, located near the centre of the Fornax galaxy cluster, at a distance of 20 Mpc. Our aim was toRead More →

Recommendations for the Astronomy Graduate Admissions Process Emily M. Levesque, Courtney D. Dressing, Rachel Ivie, Grace Krahm, Meredith A. MacGregor, Daniel R. Piacitelli, Tom Rice arXiv:2605.00992v1 Announce Type: new Abstract: As the AAS Working Group on Graduate Admissions (WGGA) we are sharing brief recommendations for improving and standardizing key elements of the graduate admissions process in astronomy. Most astronomy graduate programs have large areas of overlap in their admissions processes; however, the existing small variations in requirements and mismatches in communication and transparency make admissions more challenging for students and programs alike. To improve this situation, and building on the work presented in the AASRead More →

Kozai-driven mass loss of the circumbinary disk in D9 in orbit around the supermassive black hole Sgr A* Yannick Badoux, Lucas Pouw, Tim van der Vuurst, Simon Portegies Zwart arXiv:2604.09856v2 Announce Type: replace Abstract: The supermassive black hole (Sgr A*) in the Galactic center is surrounded by the S-star cluster consisting of young stars on eccentric orbits. Recently, the S-star binary, called D9, was found to be orbited by a circumbinary disk. Due to the gravitational interaction between Sgr A* and the binary, the disk could be short-lived. We investigate the evolution of the disk around a stellar binary while orbiting Sgr A*. We useRead More →

Implications of textit{SARAS3} data for Coulomb-like interacting dark matter Shikhar Mittal, Prakhar Bansal, Harry Bevins, Saurabh Singh arXiv:2605.00991v1 Announce Type: new Abstract: The 21-cm signal from cosmic dawn is a potentially sensitive probe of interactions between dark matter (DM) and baryons. We investigate the implications of the SARAS3 non-detection in the 55.5-84.4 MHz band for Coulomb-like interacting DM (IDM). In contrast to earlier constraint analyses that focused primarily on baryon cooling, we model the interaction self-consistently by including both excess cooling of the gas and the suppression of structure formation, which delays the onset of star formation and hence suppresses the Ly$alpha$, X-ray, and ionizingRead More →

A broadband search for coherent radio emission in cataclysmic variables Margaret E. Ridder, Paul E. Barrett, Craig O. Heinke, Gregory R. Sivakoff arXiv:2603.03209v2 Announce Type: replace Abstract: Radio observations of cataclysmic variables have revealed a variety of behavior. From some systems, we see bright unpolarized radio flares occurring during dwarf nova outbursts, consistent with synchrotron emission from jets. In others, we see highly polarized emission, restricted in frequency, superimposed on a flat-spectrum continuum, suggesting a coherent emission process. Here, we present spectro-temporal analysis of 2–4 GHz and 8–12 GHz VLA observations of 6 cataclysmic variables. Our results show both broad- and narrow-band, highly polarized, variableRead More →

Coverage is not enough: Frequentist tests of simulation-based inference for primordial non-Gaussianity Toka Alokda, Cristiano Porciani, Alexander Eggemeier arXiv:2605.00980v1 Announce Type: new Abstract: (Abridged) Simulation-based inference (SBI) has emerged as a powerful framework for extracting cosmological information from complex, non-linear data where analytical likelihoods are unavailable. Its reliability is commonly assessed using coverage-based diagnostics under the prior predictive distribution, which probe calibration only in an averaged sense and do not constrain posterior behavior at fixed parameter value, the regime relevant for practical inference. We investigate these limitations in the context of primordial non-Gaussianity, parameterized by $f_mathrm{NL}$, using simulations of the dark matter halo field. WeRead More →

Stellar mass and morphology segregation in pairs and multiplets in the cosmic web G. Torres-R’ios, S. Verley, I. P’erez, M. Argudo-Fern’andez, B. Bidaran, S. Duarte Puertas, Y. K. Gonz’alez-Koda arXiv:2605.00982v1 Announce Type: new Abstract: In this work, we investigate whether the location of galaxies within the large-scale structures (LSS) of the Universe affects their stellar mass ($M_star$) and morphology. To this end, we attempt to disentangle the effects of local and large-scale environments in their distributions. We classify 25309 galaxies in the redshift range ${0.02 arXiv:2605.00982v1 Announce Type: new Abstract: In this work, we investigate whether the location of galaxies within the large-scale structures (LSS)Read More →

Merge and Strip II: Imprint of galaxy formation physics and viscosity on baryon-dominated dwarf galaxies Anna Ivleva, Klaus Dolag, Rhea-Silvia Remus, Duncan A. Forbes, Tirso Marin-Gilabert arXiv:2605.00984v1 Announce Type: new Abstract: Motivated by the discovery of peculiar dwarf galaxies inside galaxy clusters such as blue candidates (BCs), dark galaxies and ultra-diffuse galaxies (UDGs), we present hydrodynamic simulations of galaxy mergers in cluster environments. We vary the viscosity and stellar feedback prescriptions, realistically modelling possible conditions for hydrodynamic drag and fluid instabilities, as well as internal destabilization through stellar feedback-driven heating and gas loss. We find that long-lived tidal dwarf galaxies (TDGs) can form throughout allRead More →

Tidal pre-conditioning and ram-pressure stripping in NGC 1427A. Deep VLT/MUSE spectroscopy and FUV-to-radio observations trace a Fornax Cluster dwarf in transformation J. P. Carvajal, T. H. Puzia, M. Bla~na, P. K. Nayak, K. Fahrion, M. Hilker, E. Emsellem, E. D. Skillman, M. D. Mora, B. Miller, Y. Ordenes-Brice~no, P. Eigenthaler, R. Rahatgaonkar, J. Chanam’e arXiv:2605.00988v1 Announce Type: new Abstract: The early environmental transformation of low-mass cluster galaxies from gas-rich to gas-poor remains poorly constrained, partly because clear, phase-resolved observations are rare. NGC 1427A, a disturbed star-forming dwarf in the Fornax cluster, offers a favorable case for studying this process. We aim to build a spatiallyRead More →

On the isotropy of viscosity in accretion discs Chris Nixon, Jim Pringle arXiv:2605.00985v1 Announce Type: new Abstract: Accretion discs are fundamental to many astrophysical systems, providing the conversion of gravitational potential energy into radiation that we can observe. In many systems there is evidence that discs are warped; from spatially-resolved observations of protoplanetary discs, to the features of lightcurves and line profiles from discs around supermassive black holes in galaxy centres. The dynamics of warped discs is largely controlled by the physical nature of the internal disc viscosity. While typically disc viscosity is hydromagnetic in origin, simulations of magnetized discs cannot match observed rates ofRead More →