RAS_WEB (Page 3)

Early Planet Formation in Embedded Disks (eDisk). XIX. Structures of molecular outflows Anton Feeney-Johansson, Yuri Aikawa, Shigehisa Takakuwa, Nagayoshi Ohashi, Adele Plunkett, Jes K. Jorgensen, Hsien Shang, Zhi-Yun Li, Rajeeb Sharma, Woojin Kwon, Jeong-Eun Lee, Leslie W. Looney, Yao-Lun Yang, Mayank Narang, Itziar de Gregorio-Monsalvo, eDisk team arXiv:2512.21454v2 Announce Type: replace Abstract: As part of the ALMA Large Program “Early Planet Formation in Embedded Disks” (eDisk), 12CO (2 – 1) was observed towards 19 nearby low-mass protostars. Of these objects, 15 sources are found to show molecular outflow emission. Based on their morphological and kinematical structures, the CO outflows are classified into three types: aRead More →

Massive Exchange and the Sign of the Equilateral Bispectrum Diptimoy Ghosh, Suvashis Maity, Farman Ullah arXiv:2604.06145v1 Announce Type: cross Abstract: We study the inflationary bispectrum generated by the tree-level exchange of a massive hidden-sector scalar during inflation. When the interaction between the inflaton and the hidden sector arises only from the leading boost-breaking operator of the Effective Field Theory (EFT) of inflation, the equilateral bispectrum for principal-series scalar exchange is known to be universally negative, independent of the sign of the coupling. We revisit this result within the full EFT operator basis. Using bootstrap methods, we construct the de Sitter-invariant seed four-point function and obtainRead More →

Impact of initial mass function on the chemical evolution of high-redshift galaxies Boyuan Liu, Michela Mapelli, Volker Bromm, Ralf S. Klessen, Lumen Boco, Tilman Hartwig, Simon C. O. Glover, Veronika Lipatova, Guglielmo Costa, Marco Dall’Amico, Giuliano Iorio, Kendall Shepherd, Alessandro Bressan arXiv:2506.06139v3 Announce Type: replace Abstract: Recent observations by the James Webb Space Telescope (JWST) have found evidence for an invariant relation between stellar mass, metallicity, and star formation rate up to $zsim 8$ and its breakdown at higher redshifts. Understanding the underlying physics driving such correlations is thus crucial. Here, we explore the impact of the initial mass function (IMF) on the chemical evolutionRead More →

Deep Spectroscopy with DESI for Photometric Redshift Training and Calibration Biprateep Dey, Jeffrey A. Newman, Tianqing Zhang, J. Aguilar, S. Ahlen, A. Anand, B. Andrews, S. Bailey, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, K. S. Dawson, A. de la Macorra, J. Della Costa, Arjun Dey, P. Doel, S. Ferraro, A. Font-Ribera, E. Gazta~naga, Satya Gontcho A Gontcho, D. Gruen, G. Gutierrez, J. Guy, H. K. Herrera-Alcantar, K. Honscheid, M. Ishak, R. Joyce, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, M. Landriau, L. Le Guillou, A. Leauthaud, M. E. Levi, M. Manera, P. Martini, J. McCullough, A. Meisner,Read More →

Cosmological collider signals of modular spontaneous CP breaking Shuntaro Aoki, Alessandro Strumia arXiv:2604.05548v1 Announce Type: cross Abstract: We consider a modular-invariant extension of the Standard Model. Assuming that the modulus is the inflaton, the CP-violating phases of the Yukawa couplings evolve during inflation. This dynamics favours a Higgs condensate, so that Standard Model fermions mediate a one-loop cosmological collider signal enhanced by chemical potentials. Next-generation experiments can probe sub-Planckian values of the modulus decay constant. We provide precise expressions for Dirac fermions with chemical potentials in de Sitter.arXiv:2604.05548v1 Announce Type: cross Abstract: We consider a modular-invariant extension of the Standard Model. Assuming that the modulusRead More →

Toward Early-type Eclipsing Binaries as Extragalactic Milestones: First Calibration of the SBCR from O- and B-type Stars in Detached Eclipsing Binaries M’onica Taormina, G. Pietrzy’nski, B. Pilecki, R. -P. Kudritzki, D. Graczyk, J. Puls, M. G’orski arXiv:2604.05029v1 Announce Type: new Abstract: To measure precise distances beyond the Magellanic Clouds and determine an accurate value of the Hubble constant, eclipsing binary systems composed of early-type stars can play a crucial role. However, it is fundamental to first obtain a reliable empirical surface brightness-color relation (SBCR) for the hottest possible stars. Based on our previous study of six detached eclipsing binaries composed of O- and B-type starsRead More →

Random gas motions inside sub-parsec scale supercritical filaments Chao Zhang, Tie Liu, Mika Juvela, Paolo Padoan, Hong-Li Liu, Di Li, Guido Garay, Neal J. Evans, Fengwei Xu, Paul F. Goldsmith, Qizhou Zhang, Kee-Tae Kim, Yankun Zhang, Zhiyuan Ren, Mengke Zhao arXiv:2604.04501v2 Announce Type: replace Abstract: Supercritical gas filaments in molecular clouds host the dense cores in which new stars form. The mechanisms governing their formation and subsequent gas accretion remain poorly understood. In this study, we conduct a statistical analysis of a large sample of sub-parsec supercritical filaments using H13COp J=1-0 data from the ALMA Three-millimeter Observations of Massive Star-forming regions (ATOMS) Survey. We identifiedRead More →

Winding Back the Clock: Recent Star Formation Histories of Massive Quiescent Galaxies Are Consistent With Their Rapid Number Density Evolution Since $mathbf{zsim7}$ Yunchong Zhang, Zhiyuan Ji, Rachel Bezanson, Christina C. Williams, Gabriel Brammer, Aidan P. Cloonan, Anna de Graaff, Jenny E. Greene, Michaela Hirschmann, Christian Kragh Jespersen, Gourav Khullar, Claudia del P. Lagos, Joel Leja, Michael V. Maseda, Ian McConachie, Pascal A. Oesch, Sedona H. Price, David J. Setton, Katherine A. Suess, Katherine E. Whitaker arXiv:2604.05024v1 Announce Type: new Abstract: Massive quiescent galaxies have been identified out to $zsim7$ in early JWST data in a substantial excess ($rm gtrsim 1,dex$ at $z>4$) of number densitiesRead More →

Characterizing the Gamma-ray Emission from Low-Luminosity AGN Chris Karwin, Nikita Khatiya, Margot Boughelilba, Xiurui Zhao, Anita Reimer, Marco Ajello arXiv:2604.05028v1 Announce Type: new Abstract: A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $lesssim 10^{42} mathrm{erg s^{-1}}$. Although high-energy gamma-ray emission is predicted from both the jets and disks of LLAGN, to date only four have been detected by the Fermi Large Area Telescope (Fermi-LAT). In this work, we therefore conduct a comprehensive study of all the LLAGN from the Palomar spectroscopic survey of bright, northern galaxies, including both subthreshold and detected gamma-rayRead More →

PANORAMIC: The Dawn of Massive Quiescent Galaxies I. Number Density and Cosmic Variance from 1000 arcmin$^2$ NIRCam Imaging Zhiyuan Ji, Christina C. Williams, Peter Behroozi, Andrea Weibel, Christian Kragh Jespersen, Pascal A. Oesch, Rachel Bezanson, Katherine E. Whitaker, Jenny E. Greene, Gabriel Brammer, Pratika Dayal, Ivo Labb’e, Sinclaire M. Manning, Pierluigi Rinaldi, Mengyuan Xiao, Yunchong Zhang arXiv:2604.05022v1 Announce Type: new Abstract: We measure the number density and field-to-field variance of massive quiescent galaxies at $zsim3$ – 8 using the JWST/NIRCam pure-parallel imaging survey PANORAMIC together with archival observations, covering an area of 0.28 deg$^2$ ($sim1000$ arcmin$^2$) in at least six filters. We identify quiescent galaxyRead More →

Electromagnetic Flares from Compact-Object Mergers in AGN Disks: Signatures and Predictions Hiromichi Tagawa, Zolt’an Haiman, Shigeo S. Kimura, Hassen M. Yesuf, Hengxiao Guo arXiv:2604.05020v1 Announce Type: new Abstract: Accretion disks in active galactic nuclei (AGN) are promising sites for mergers of stellar-mass black holes (BHs) detectable via gravitational waves (GWs). These environments facilitate both in-situ formation and dynamical capture of compact objects, and their subsequent mergers. The uncertain origin of GW events detected by LIGO, Virgo and KAGRA motivates searching for accompanying electromagnetic (EM) signatures. Here we investigate post-merger EM flares associated with jets launched from merger remnants, as well as from the shocked ambientRead More →

The neighboring stars of N6946-BH1 and the observational characteristics of failed supernovae R. For’es-Toribio, C. S. Kochanek arXiv:2604.05019v1 Announce Type: new Abstract: Stellar collapse models predict that some stars more massive than $sim$15$M_odot$ may collapse directly to a black hole, sometimes with a weak optical transient, a phenomenon known as a failed supernova. Detecting such events is challenging, but searches of vanishing stars have found two promising candidates, N6946-BH1 and M31-2014-DS1. We re-analyze the JWST data of N6946-BH1 to characterize the remnant emission of the object and its surrounding sources. We found four near-infrared stellar neighbors not related to the mid-infrared emission of the candidate.Read More →

The Bondi universe: Can negative mass drive the cosmological expansion? Giovanni Manfredi, Jean-Louis Rouet, Bruce Miller arXiv:2601.22910v2 Announce Type: replace Abstract: We identify a new cosmological coincidence that parallels the well-known matter/dark-energy coincidence: the present-epoch transition of the universe from a weakly coupled (collisionless) to a strongly coupled (collisional) gravitational regime. Within a cosmological model containing equal amounts of positive and negative Bondi masses — consistent with the weak equivalence principle and momentum conservation — we show that this coupling transition naturally coincides with the shift from a coasting to an accelerating expansion. A linear response analysis of the corresponding Vlasov-Poisson system reveals that mixedRead More →

Universal Dark-matter Density Profiles of Cosmic Filaments Peng Xu, Fangzhou Jiang, Farhanul Hasan, Joanna Woo, Douglas Hellinger, Joel R. Primack, Sandra M. Faber, David Koo arXiv:2604.05033v1 Announce Type: new Abstract: We present a comprehensive analysis of the radial dark-matter (DM) density profiles of cosmic filaments in the hydrodynamical simulation TNG50. The cosmic web is extracted from high-resolution density grids at redshifts $z =$ 0, 0.5, 1, 2 and 3 using the DisPerSE algorithm. We show that the filament spine locations returned directly by DisPerSE do not accurately reflect the true density ridges. To address this issue, we introduce a “shrinking-cylinder” re-centering algorithm, which significantly increasesRead More →

The diagnostic temperature discrepancy as evidence for non-Maxwellian coronal electrons Victor Edmonds arXiv:2603.10040v2 Announce Type: replace Abstract: Two independent electron temperature diagnostics applied to the quiet solar corona yield systematically different results. Radio brightness temperatures from the Nancay Radioheliograph indicate T_e ~ 0.6 MK, while hydrostatic scale-height modeling requires T_e ~ 1.5 MK. Both probe electrons; they disagree by a factor of R = 2.4 +/- 0.3. This discrepancy persists across eight years spanning solar minimum and is confirmed by LOFAR at lower frequencies. We consider turbulent scattering, which suppresses brightness temperature, but comparison with the FORWARD/PSIMAS Maxwellian model shows the standard thermal structure predictsRead More →

Two-stage disruption of resonant chains Nick Choksi, Yoram Lithwick, Eugene Chiang, Rixin Li arXiv:2604.05035v1 Announce Type: new Abstract: TESS has made clear that most close-in planets were born in chains of mean-motion resonances that break on a characteristic timescale of 100 Myr. This observation is surprising because the same dissipative forces that capture planets into resonance render their orbits long-term stable. We explore a two-stage disruption scenario for resonant chains of super-Earths. First, the chains have their (free) eccentricities excited by some mechanism. We show that any such mechanism that seeds eccentricities of a few percent sets in motion a second stage of dynamical instabilityRead More →

FluxMC: Rapid and High-Fidelity Inference for Space-Based Gravitational-Wave Observations Bo Liang, Chang Liu, Hanlin Song, Tianyu Zhao, Minghui Du, He Wang, Haohao Gu, Sensen He, Yuxiang Xu, Wei-Liang Qian, Li-e Qiang, Peng Xu, Ziren Luo, Mingming Sun arXiv:2604.04957v1 Announce Type: new Abstract: Bayesian inference in the physical sciences faces a fundamental challenge: the imperative for high-fidelity physical modeling often clashes with the intrinsic limitations of stochastic sampling algorithms. Complex, high-dimensional parameter spaces expose the universal vulnerability of conventional methods, e.g., Markov Chain Monte Carlo (MCMC), which struggle with the prohibitive costs of likelihood evaluations and the risk of entrapment in local optima. To resolve thisRead More →

Lithium and the evolution of intermediate-mass T Tauri and Herbig stars. Rotation, accretion, and planets I. Mendigut’ia, J. Campbell-White, B. Montesinos, J. Maldonado, L. Fullana-Garc’ia, G. M. Mirouh, G. Meeus, M. Vioque, A. Sicilia-Aguilar, M. R. Zapatero-Osorio, E. Villaver, R. Kahar arXiv:2604.05040v1 Announce Type: new Abstract: (Abridged) We contribute to our understanding of the evolution of young intermediate-mass stars by providing a comprehensive analysis of their lithium (Li) content. A sample of 71 intermediate-mass T Tauri (IMTT) and Herbig stars within the mass range 1.5 — 3.5 M$_{odot}$ was carefully selected for the analysis. Metallicities, rotational velocities, and accretion rates were obtained from spectra. TheRead More →

Revisiting The Gravitational Mirroring In Presence of Compact Objects Bikramarka S Choudhury, Aritra Sanyal, Md Khalid Hossain, Farook Rahaman arXiv:2604.05009v1 Announce Type: cross Abstract: We propose a novel concept of astrophysical mirroring in the schwarzschild framework, which emerges as a direct consequence of gravitational lensing effects occurring in the immediate vicinity of extremely dense massive objects within spacetime. Through rigorous theoretical calculations and numerical ray-tracing analysis, we demonstrate that sufficiently compact astrophysical objects possess the capability to induce such extreme curvature in spacetime that the resulting gravitational field can bend light rays to extraordinary degrees, creating what we term a “reflection image” or mirror-like appearanceRead More →

Wide Jets or Low Rates: Reconciling Short GRB and Gravitational-Wave Neutron Star Merger Rates Keerthi Kunnumkai, Antonella Palmese, Brendan O’Connor, Amanda Farah, Ignacio Magana Hernandez arXiv:2604.05046v1 Announce Type: new Abstract: Gravitational wave (GW) and short Gamma Ray Burst (sGRB) observations provide us with complementary views of compact object mergers. The paucity of binary neutron star merger (BNS) detections in the latest LIGO/Virgo/KAGRA (LVK) observing run raises the question of whether the GW merger rates are sufficient to explain the observed sGRB rate with compact object mergers alone. We investigate this connection using the latest merger rate constraints from the fourth LVK observing run (O4) andRead More →