RAS_WEB (Page 2)

TRINITY: A coupled model of winds, radiation, and photoionised gas in molecular clouds. I. Methods and validation Jia Wei Teh, Ralf S. Klessen, Simon C. O. Glover, Kathryn Kreckel arXiv:2605.27517v1 Announce Type: new Abstract: Multi-wavelength surveys place cloud dispersal at 1-5 Myr after massive stars emerge, before the first supernovae. Whether a cloud disperses, re-collapses, or leaks Lyman-continuum (LyC) photons depends on how pre-supernova winds, radiation pressure, and photoionised-gas pressure ($P_{rm HII}$) couple to the shell. We introduce TRINITY, a 1D thin-shell code that succeeds WARPFIELD. TRINITY evolves the bubble-shell structure under winds, supernovae, direct and dust-reprocessed radiation pressure, $P_{rm HII}$, and gravity. A phase-awareRead More →

Turbulence in Primordial Dark Matter Halos and Its Impact on the First Star Formation Meng-Yuan Ho, Ke-Jung Chen, Pei-Cheng Tung arXiv:2505.23768v2 Announce Type: replace Abstract: We present high-resolution simulations of the first star-forming clouds in 15 minihalos with masses ranging from $sim 10^5$ to $10^7 text{M}_{odot}$ at redshifts $z sim 17-20$, using the GIZMO code. Our simulations incorporate detailed primordial gas physics and adopt initial conditions from the state-of-the-art TNG cosmological simulations. To achieve the required resolution, we apply a particle-splitting technique that increases the resolution of the original TNG data by a factor of $sim 10^5$, reaching gas and dark matter particle masses ofRead More →

DebrisWatch II: Digging deeper for geosynchronous debris James A. Blake, Benjamin F. Cooke, Cristina Paragini, William Feline, Christopher A. Onken, Don Pollacco, Grant Privett, Toshifumi Yanagisawa, Robert Airey, Ioannis Apergis, Roberto Armellin, Lily Beesley, Paul Chote, Anna-Maria Cutolo, Stuart Eves, Tomoko Fujiwara, Daisuke Kuroda, Isobel S. Lockley, Alexander MacManus, James McCormac, Morgan A Mitchell, Tokuhiro Nimura, Kota Nishiyama, Shin-Ichiro Okumura, Thomas Schildknecht, Billy Shrive, Seitaro Urakawa, Dimitri Veras, Phineas Whitlock, Christian Wolf arXiv:2605.27516v1 Announce Type: new Abstract: The geosynchronous (GSO) debris environment is continually evolving. Regular monitoring of the region is consequently of great importance, though the trade-off between coverage and sensitivity makes this challengingRead More →

Inflation with vector fields revisited: non-Gaussianities Chong-Bin Chen arXiv:2605.28752v1 Announce Type: cross Abstract: We revisit the resulting bispectrum of inflation with kinetic-coupled vector fields by organizing the dynamics in terms of $h$, which measures the vector kinetic contribution relative to that of the scalar field. We evaluate the bispectrum in the strong-vector regime and derive a low-energy effective field theory (EFT) for the large-$h$ regime. For $hgg1$, the entropic perturbation becomes heavy and can be integrated out; the remaining curvature mode has an imaginary sound speed and undergoes transient growth before horizon crossing. In contrast to $hll1$ regime, where transfer from the vector sector persistsRead More →

BlackHoleWeather — Jet-regulated chaotic cold accretion across the meso scale: Variability and kinematics Vieri Cammelli, Massimo Gaspari, Filippo Barbani, Olmo Piana, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Roberto Serafinelli, Pasquale Temi, Francesco Salvestrini, Michael Reefe, Filippo M. Maccagni, Francesco Tombesi arXiv:2605.27511v1 Announce Type: new Abstract: Chaotic cold accretion (CCA) predicts that supermassive black holes are fed by multiphase clouds condensing from turbulent hot atmospheres. In jet-regulated systems cold gas must also remain dynamically connected to the central accretion region. We investigate how a self-regulated kinetic jet modifies the kinematics, radial transport, and variability of CCA across the meso-scale of a typical galaxy-group atmosphere. TheRead More →

Dynamical Resolution of the Cosmic Coincidence Problem in Non-Interacting Holographic Dark Energy via Einstein-Cartan Torsion Yongjun Yun, Kyungduk Kim, Jungjai Lee arXiv:2605.27973v1 Announce Type: cross Abstract: We investigate the cosmic coincidence problem in non-interacting holographic dark energy with the Hubble radius as the infrared cutoff in Einstein-Cartan gravity. In general relativity, this cutoff gives a dust-like equation of state in the non-interacting case, whereas interacting models require a phenomenological dark sector coupling and yield a constant density ratio. We show that the Einstein-Cartan torsion scalar $Phi$, compatible with the cosmological principle, with the self-consistent scaling behavior $Phisim a^{-3}$, makes the density ratio $requiv rho_m/rho_X$ dynamicalRead More →

The strength of Type-C quasi-periodic oscillations in black hole X-ray binaries correlates with the jet inclination F. M. Vincentelli, N. Bollemeijer, A. Veledina, D. Altamirano, Q. Bu, F. Carotenuto, P. Casella, Y. Cavecchi, R. Ma, G. Marcel, G. Mastroserio, S. Motta, L. Zhang arXiv:2605.27510v1 Announce Type: new Abstract: X-ray quasi-periodic oscillations (QPOs) are a characteristic feature of low-mass X-ray binaries (LMXBs). These oscillations have been studied for decades and revealed a rich and complex phenomenology that is still not fully understood. RXTE archival studies have shown that the amplitude of these oscillations differs significantly between black holes (BH) with high or low inclination. Yet, theRead More →

May Negative Mass Objects exist in the sky? Shin’ichi Nojiri, S. D. Odintsov arXiv:2602.15058v2 Announce Type: replace-cross Abstract: We conjecture the possibility of negative mass objects (NMOs) existing in the sky. It is shown that they may not be so exotic as usually expected. We show that NMOs appear as solutions of standard gravitational equations if we consider the system of a compact positive mass object, cosmological fluid and negative cosmological constant. We also construct models which generate such NMOs as solutions within the two-scalar theory and scalar-Einstein-Gauss-Bonnet gravity inspired by string theory. The orbits of the photon and massive particles are investigated in theRead More →

SPHEREx confirms predictions for artificial satellite trail pollution in Low Earth Orbit Alejandro S. Borlaff, Pamela M. Marcum, Steve B. Howell, Pablo M. S’anchez-Alarc’on, David Dubois, Jonathan McDowell arXiv:2605.27501v1 Announce Type: new Abstract: The number of artificial satellites in Low Earth Orbit (LEO) is increasing at an exponential rate since 2019. Satellites are visible to both ground and space telescopes, and their bright emission in optical, infrared, and radio-wavelengths contaminate astronomical observations, degrading the data’s scientific value. Recent simulations forecast that if all satellite constellations listed in current launch manifests are deployed to LEO, satellite trails will appear in up to 96% of the imagesRead More →

BlackHoleWeather — Spin-coupled chaotic cold accretion across the meso-scale: Morphology and thermodynamics Olmo Piana, Massimo Gaspari, Filippo Barbani, Vieri Cammelli, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Francesco Salvestrini, Ashkbiz Danehkar, Francesco Tombesi, Pasquale Temi, Filippo M. Maccagni, Martin Fournier arXiv:2605.27502v1 Announce Type: new Abstract: Supermassive black hole (SMBH) spin is a key but poorly constrained ingredient of the feeding-feedback loop. Chaotic cold accretion (CCA) of cold gas clouds delivers rapidly varying three-dimensional torques that drive spin evolution and jet-axis reorientation, and in turn spin regulates jet power. We introduce a time-dependent SMBH spin model linking resolved multiphase feeding at meso scales to unresolved relativisticRead More →

BlackHoleWeather — Jet-regulated chaotic cold accretion across the meso scale: Morphology and thermodynamics Vieri Cammelli, Massimo Gaspari, Olmo Piana, Filippo Barbani, Giovanni Stel, Davide M. Brustio, Valeria Olivares, Francesco Salvestrini, Ashkbiz Danehkar, Michael Reefe, Pasquale Temi, Filippo M. Maccagni, Francesco Tombesi, Martin Fournier arXiv:2605.27503v1 Announce Type: new Abstract: How mechanical AGN feedback couples to multiphase condensation across scales remains a problem in galaxy groups and clusters. It is unclear how jets reshape the chaotic cold accretion (CCA) cycle and regulate black-hole fueling. BlackHoleWeather aims to build a unified description of the AGN baryon cycle across horizon, galactic, and group scales. Here we focus on howRead More →

BlackHoleWeather — Chaotic cold accretion across the meso-scale: Morphology and thermodynamics Filippo Barbani, Massimo Gaspari, Vieri Cammelli, Olmo Piana, Fred J. Jennings, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Filippo M. Maccagni, Martin Fournier, Francesco Tombesi, Pasquale Temi, Fabrizio Fiore, Roberto Serafinelli, Ashkbiz Danehkar arXiv:2605.27507v1 Announce Type: new Abstract: Supermassive black holes (SMBHs) self-regulate galaxies, groups, and clusters, yet the pathway transporting gas from halo scales to sub-pc radii remains debated. In hot stratified atmospheres, subsonic turbulence can trigger nonlinear thermal instability and a multiphase condensation cascade, producing chaotic time-variable BH `weather’. A key missing link is how the meso-scale connects halo rain to nuclearRead More →

BlackHoleWeather — Chaotic cold accretion across the meso-scale: Variability and kinematics Filippo Barbani, Massimo Gaspari, Olmo Piana, Vieri Cammelli, Fred J. Jennings, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Filippo M. Maccagni, Martin Fournier, Francesco Tombesi, Pasquale Temi, Fabrizio Fiore, Roberto Serafinelli, Ashkbiz Danehkar arXiv:2605.27504v1 Announce Type: new Abstract: Accretion onto supermassive black holes (SMBHs) in realistic halos is time-variable, governed by turbulence, cooling, and multiphase condensation. In chaotic cold accretion (CCA), clouds and filaments condense out of the hot gas and feed the SMBH stochastically. We investigate how turbulence regulates the variability, radial transport, and kinematics of CCA, focusing on the meso-scale connecting haloRead More →

Reconstructing the Globular Cluster Initial Mass Function from Present-Day Globular Cluster Systems Elizabeth Moreno-Hilario, Hui Li, Luis A. Martinez-Medina arXiv:2605.27509v1 Announce Type: new Abstract: The near-universal turnover mass of the present-day globular cluster mass function (GCMF), $M_{rm TO} sim 2 times 10^5 {rm M_odot}$, is a well established observational feature across galaxies of different types and masses, providing an important empirical benchmark for understanding the globular cluster initial mass function (GCIMF). Competing explanations of this property invoke either dynamical evolution from an initial power-law distribution or an imprint of cluster formation physics. We address this problem by reconstructing the high-mass regime of the GCIMF byRead More →

BlackHoleWeather — Spin-coupled chaotic cold accretion across the meso scale: Variability and kinematics Olmo Piana, Massimo Gaspari, Vieri Cammelli, Filippo Barbani, Davide M. Brustio, Giovanni Stel, Valeria Olivares, Ashkbiz Danehkar, Pasquale Temi, Roberto Serafinelli, Francesco Salvestrini, Filippo M. Maccagni, Francesco Tombesi arXiv:2605.27508v1 Announce Type: new Abstract: Supermassive black hole (SMBH) spin records the vector history of accretion. In chaotic cold accretion (CCA), this history is set by clouds and filaments whose torques can add coherently, cancel, or reverse before reaching the horizon-scale closure. We test whether halo stirring regulates SMBH spin by changing the radial continuity and torque coherence of the meso-scale accretion bridge. WeRead More →

Formation of neutron stars via accretion-induced collapse and core-merger-induced collapse inside planetary nebulae from white dwarf binaries Iminhaji Ablimit arXiv:2407.03985v3 Announce Type: replace Abstract: The accretion-induced collapse (AIC) and core-merger-induced collapse (CMIC) from oxygen-neon-magnesium (ONeMg) white dwarf (WD) binaries inside planetary nebulae (PNe) have not been previously even mentioned in the literature. In this paper, I propose and study two possible WD binary channels for AIC and CMIC to form neutron stars (NSs) within PNe. First, using simulations performed with the textsc{MESA} stellar evolution code, I present a scenario in which NSs form via the AIC of ONeMg WDs inside PNe–referred to here as symbioticRead More →

First-Order Perturbations of Covariant Maxwell Equations in Gravitational Waves Lingyue Lou, Haorong Wu, Xi-Long Fan arXiv:2605.28663v1 Announce Type: cross Abstract: We present a systematic theoretical framework for investigating first-order electromagnetic (EM) perturbations induced by gravitational waves (GWs). Beginning with the covariant Maxwell equations, we derive the complete first-order perturbation equations in terms of both the EM field tensor and the four-potential, demonstrating their equivalence alongside the residual gauge invariance under the Lorenz gauge condition. Furthermore, explicit first-order expressions for the induced electric and magnetic fields, as well as the associated EM energy-momentum tensor, are obtained. As an explicit illustration, we analytically evaluate the interaction betweenRead More →

GASTRO library II: Exploring Chemical Bimodalities in Disk Galaxies with GSE-like Mergers and Massive Star-forming Clumps Jo~ao A. S. Amarante, Chervin F. P. Laporte, Victor P. Debattista, Leandro Beraldo e Silva, Guilherme Limberg, H’elio D. Perottoni, Zhao-Yu Li, Lais Borbolato, Karl Fiteni, Chengye Cao, Nathan Deg, Tigran Khachaturyants, Xiaojie Liao arXiv:2512.01293v2 Announce Type: replace Abstract: We use several smoothed particle hydrodynamics+N-body models as part of the GASTRO library to study the role of high-density star-forming clumpy regions and a single merger on the formation of the $alpha$-rich and $alpha$-poor populations in the disk galaxies. These experiments are tailored to mimic what is expected to beRead More →

Prototyping of 6.2-mm-Pitch Fiber Positioner Modules for Stage-V Telescope Instrumentation Malak Galal, Maxime Rombach, Jonathan Wei, Oliver Pineda Su’arez, Ricardo Ara’ujo, S’ebastien Pernecker, Abby Bault, Joseph Harry Silber, Nicholas Wenner, Robert Besuner, David Kirkby, William Van Shourt, Stefane Caseiro, Corentin Magnenat, Yves Moser, Yasuyuki Kobayashi, Eri Fukushima, Satoshi Sonoda, Ayumu Suto, David Schlegel, Jean-Paul Kneib arXiv:2508.19711v3 Announce Type: replace Abstract: Small-pitch populated focal planes are essential enabling technologies for the next generation of highly multiplexed astronomical instruments. As modern astrophysics relies on massive spectroscopic surveys to study dark energy, dark matter, and galactic assembly, the ability to observe thousands of targets simultaneously has become paramount.Read More →

Eccentric Stellar-mass Binary Black Holes: Population, Detectability, and Waveform Analysis in the LISA and LIGO Era Zeyuan Xuan, Smadar Naoz, Kyle Kremer, Michael L. Katz, Bence Kocsis, Erez Michaely arXiv:2605.15265v2 Announce Type: replace Abstract: Eccentric binary black holes (BBHs) formed through dynamical interactions can significantly contribute to gravitational wave (GW) detections. In this work, we present a simulated catalog of dynamically-formed, stellar-mass BBHs in the local universe, incorporating contributions from the Galactic field (flyby interactions), Galactic nucleus (eccentric Kozai-Lidov evolution), and globular clusters (N-body interactions). Our results predict a wide, highly eccentric BBH population in the Milky Way (MW), with source counts of $sim 36,Read More →