UchUchU

研究動向

宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.GA

SED Fitting of the Globular Clusters in Abell 2744 at z=0.3

Jinoo Kim, William E. Harris

We present a spectral energy distribution (SED) fitting analysis of globular cluster (GC) candidates in Abell 2744, a massive galaxy cluster at redshift z = 0.308 with a lookback time of 3.5 Gyr, using deep JWST/NIRCam photometry. By leveraging observations in eight broadband filters (F070W to F444W), we derive constraints on GC masses, ages, and metallicities of 69 GC candidates, refining previous studies focused on color-magnitude analysis. The inferred GC masses predominantly fall near 10^7 M…

詳細を見る →
astro-ph.EP

JWST/MIRI Reveals the Evolution from Molecular to Atomic Disk Winds

Naman S. Bajaj, Ilaria Pascucci, Sylvie Cabrit, Suzan Edwards, Gabriele Cugno, Andrew D. Sellek, Joan R. Najita, Ke Zhang et al.

The evolution and dispersal of protoplanetary disks--governed by accretion, magnetically launched jets and winds, and photoevaporative winds--fundamentally shape planetary systems. Determining how these mass-loss processes co-evolve is crucial for constraining planet formation pathways. We analyze archival JWST/MIRI/IFU data of 72 inclined (i>40deg) mostly ClassII disks to identify and characterize spatially resolved jets and winds, focusing on [NeII] and H2 lines. Extended emission in H2 S(1),…

詳細を見る →
astro-ph.IMastro-ph.EP

Jointly Modeling Roman Coronagraph Astrometry and Photometry Improves Orbital Parameter Estimates

Farrah Molina, Sarah Blunt, Jason Wang

Launching in 2027, the Nancy Roman Grace Space Telescope (Roman) has the potential to directly image exoplanets in reflected light for the first time. Roman imaging will introduce new constraints on exoplanet orbital parameters, since reflected-light intensity depends on orbital phase. In this Note, we discuss an addition to the open-source Python package orbitize!, which allows users to model exoplanet orbits using joint constraints from astrometry and photometric variations due to orbital phas…

詳細を見る →
astro-ph.GA

Outflows in super-Eddington quasars drive clumpy circumgalactic medium and extended H$α$ nebulae at $z \gtrsim 6$

Lucas Tortora, Tiago Costa, Debora Sijacki, Jake S. Bennett

The discovery of gargantuan black holes with masses exceeding a billion solar masses at $z\gtrsim6$ suggests rapid black hole growth and significant energy input into their host galaxies in the early Universe. With JWST probing previously unseen phases of the interstellar (ISM) and circumgalactic (CGM) medium around $z > 6$ quasars, detailed theoretical studies can now be directly confronted with observations. We use zoom-in simulations of a massive protocluster at $z\sim6$, employing both the f…

詳細を見る →
astro-ph.GA

Megaparsec-Scale Neutral Hydrogen Flows in the Neighborhood of Hickson Compact Group 100

Qingzheng Yu, Taotao Fang, Enrico M. Di Teodoro, Cheng Cheng, Cong Kevin Xu

The evolution of galaxies is strongly influenced by their ability to exchange gas with their surroundings, yet direct observational constraints on these processes remain scarce. Using ultra-deep neutral hydrogen (HI) observations with the Five-hundred-meter Aperture Spherical Telescope (FAST), we detect a diffuse HI structure extending over $\sim$1 Mpc around the compact galaxy group HCG 100, with integrated column densities down to $\sim$$8.6\times10^{17}$ cm$^{-2}$. This structure is among the…

詳細を見る →
astro-ph.IM

Low-cost, ultra-wideband, differential low-noise amplifier for interferometric radio telescopes

Sophia Da Costa, Albert Wai Kit Lau, Keith Vanderlinde

We present a low-cost, ultra-wideband, dual-polarized differential low-noise amplifier that eliminates the need for a pre-amplification balun. Built entirely from commercial surface-mount components, the design costs approximately 20 US dollars per unit. The amplifier has been characterized through laboratory gain and noise measurements together with feed-coupled hot-cold testing at the Dominion Radio Astrophysical Observatory. A noise figure close to 0.3 dB is demonstrated across a 10:1 bandwid…

詳細を見る →
gr-qcastro-ph.HE

Viscosity effects on the shadow of a non-rotating black hole

Sayantani Lahiri, Sergio Gimeno-Soler, Alejandro Cruz-Osorio, José A. Font, Ziri Younsi

We study the effect of shear viscosity in stationary magnetized accretion tori on synthetic images of non-rotating black hole shadows. Shear viscosity and spacetime-curvature contributions are introduced perturbatively in the tori through first and second-order transport coefficients within a second-order causal theory of non-ideal relativistic hydrodynamics. Synthetic black hole shadow images at 230\,GHz are obtained via general relativistic radiative transfer computations assuming thermal sync…

詳細を見る →
astro-ph.GA

The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 2: Effects of a Major Galaxy Merger on the Stellar Morphology of a Milky Way-mass Galaxy Progenitor

Thinh Huu Nguyen, Kirk S. S. Barrow, Minyong Jung, Ramón Rodríguez-Cardoso, Santi Roca-Fàbrega, Ji-hoon Kim, Joel R. Primack, Kentaro Nagamine et al.

Galaxy mergers, with their high sensitivity to initial conditions, provide a valuable setting for comparative studies of galaxy simulation codes. Following our first paper focusing on merger-driven star formation, we present a code comparison examining the morphological transformation impact of a major galaxy merger at $z \approx 4.5$ on a Milky Way-mass galaxy progenitor. Our analysis employs nine state-of-the-art codes from the AGORA CosmoRun cosmological zoom-in simulation suite. For this mer…

詳細を見る →
astro-ph.GA

The AGORA High-resolution Galaxy Simulations Comparison Project. IX - Part 1: Effects of a Major Galaxy Merger on Star Formation of a Milky Way-mass Galaxy Progenitor

Thinh Huu Nguyen, Kirk S. S. Barrow, Minyong Jung, Ramón Rodríguez-Cardoso, Santi Roca-Fàbrega, Ji-hoon Kim, Joel R. Primack, Kentaro Nagamine et al.

Given their highly nonlinear dynamics and sensitivity to initial conditions, galaxy mergers are a compelling area to conduct a simulation code comparison. We perform a comparative study of a major galaxy merger at $z \approx 4.5$ in cosmological zoom-in hydrodynamic simulations of a Milky Way-mass galaxy progenitor. The comparison employs the AGORA CosmoRun suite of nine well-calibrated, state-of-the-art numerical codes, each adopting a different stellar feedback scheme. We find that the evoluti…

詳細を見る →
cs.LGastro-ph.COastro-ph.GAhep-exhep-ph

An Introduction to Bayesian and Frequentist Simulation-Based Inference with Machine Learning

Maximilian Dax, Theo Heimel, Gilles Louppe

Simulation-based inference (SBI) with machine learning is an increasingly important tool for solving inverse problems in science and engineering, including parameter inference and the inversion of detector effects. We provide an overview of the Bayesian and frequentist statistical frameworks, describe how machine-learning-based SBI methods, such as neural posterior estimation and neural likelihood estimation, can be used for parameter estimation within these frameworks, and show that the same me…

詳細を見る →
astro-ph.GA

Different paths, same appearance: an intermediate-age red nugget at z~0.13

F. La Barbera, F. Buitrago, I. Ferreras, C. Tortora

Massive ultra-compact galaxies are commonly regarded as nearby relics of the compact quiescent population at z~2-3, and detailed studies have focused so far only on old systems in dense environments. Here we present a spatially resolved analysis of G79071, an ultra-compact (R_e 5Gyr) component. The central metallicity is supersolar and decreases with radius, while most abundance ratios show flat radial trends and are consistent with typical massive, low-redshift ETGs at similar velocity dispersi…

詳細を見る →
astro-ph.HE

XMM-Newton and Swift Unveil Another X-Ray Transient in NGC 4945, XMM J130514.64-493311.27

Ryan W. Pfeifle, Kimberly A. Weaver, Jenna M. Cann, Murray Brightman, Miranda McCarthy

NGC 4945 hosts a Compton-thick, low luminosity AGN and a nuclear starburst in its core and has been the subject of many previous X-ray investigations of the AGN emission structure, nuclear starburst properties, and ultraluminous X-ray (ULX) source populations. Indeed, NGC 4945 has proven to be a rich system for ULX and X-ray transients, with at least four X-ray transients being reported over the last 15 years. Here we report the detection of an X-ray transient source, XMM J130514.64-493311.27, i…

詳細を見る →
astro-ph.GA

Identifying and Distinguishing Quenching Galaxies with Spatially Resolved Star Formation in the Hubble Frontier Fields

Cameron Lawlor-Forsyth, Michael L. Balogh, Sean L. McGee, Gregory H. Rudnick

We investigate the nature and prevalence of different quenching signatures for 1437 galaxies with $M_{*} \geqslant 10^{8}~\mathrm{M}_{\odot}$ and $\text{SFR} \geqslant 10^{-3}~M_{\odot}~\text{yr}^{-1}$ in the Hubble Frontier Fields through spatially resolved spectral energy distribution fitting with \texttt{FAST++}. We use the morphological metrics previously presented in our series of investigations to quantify the distribution of star formation, and use a $k$-nearest neighbors algorithm to cla…

詳細を見る →
gr-qcastro-ph.HEastro-ph.IM

A story about a tipsy kangaroo: Reversible jump MCMC for model selection in the analysis of gravitational-wave signals from the coalescence of compact objects

Anna Puecher, Tim Dietrich, Hauke Koehn, Jonathan Gair, Gregory Ashton, Luca Negri, Anuradha Samajdar

Bayesian inference is commonly employed in the analysis of gravitational-wave signals not only to estimate the source parameters, but also for model selection. The latter provides insight into the physics of the source and has the potential to inform the direction for future model development. Although model comparison is usually performed by analyzing the data separately with different models and comparing the obtained Bayesian evidences, an alternative approach consists in sampling directly ov…

詳細を見る →
astro-ph.SR

CO second overtone line variability in three carbon-rich early post-AGB stage stars

Kārlis Puķītis

Near-infrared CO molecular lines are suggested to be linked with dynamic processes in post-AGB stars; however, they have not been investigated at high spectral resolution. CO second overtone line variability in the H-band is presented for the cool carbon-rich post-AGB stars IRAS 22272+5435, IRAS Z02229+6208, and IRAS 20000+3239. CO features are observed to change intensity, shape, and radial velocity as well as switch between emission and absorption during the pulsation cycle. At all times, the…

詳細を見る →
astro-ph.GA

ALMA CO-CAVITY II. Resolved Scaling Relations in Void Galaxies

S. B. De Daniloff, D. Espada, S. Duarte Puertas, Y. K. González-Koda, G. Torres-Ríos, S. F. Sánchez, R. García-Benito, S. Verley et al.

Scaling relations involving star formation rates (SFRs), molecular gas mass, and stellar mass are key to understand galaxy evolution, and have previously been explored at resolved scales. However, they have not been examined with particular emphasis on the large-scale environments (LSEs). In this work, we study the resolved Schmidt-Kennicutt relation (rSK), molecular gas main sequence (rMGMS) and star-forming main sequence (rSFMS) from a sample of 41 void galaxies (VGs) residing in the least den…

詳細を見る →
astro-ph.HEhep-ph

Light Antinuclei Coalescence: Femtoscopic Constraints via Neural-Flow Surrogates

M. Korwieser, L. Fabbietti, B. Hashemi, L. Heinrich, M. Mahlein, D. L. Mihaylov, C. S. Zeyn

Precise predictions of cosmic-ray antinuclei fluxes, a prime dark matter signature, are limited by the lack of data constraining production rates of antinuclei. We mitigate this bottleneck with a fast, differentiable normalizing-flow surrogate for the femtoscopic source model (CECA), fit to 49 ALICE proton-proton correlation functions, and extrapolated via scaling laws to the low-multiplicity domain relevant for cosmic rays. The surrogate reproduces CECA with sub-percent emulation fidelity, yiel…

詳細を見る →
astro-ph.IMastro-ph.CO

Atmosphere mitigation in CMB observations using multi-frequency time-domain component separation

Julien Tang, Shamik Ghosh, Jacques Delabrouille, John C. Groh, Oliver Jeong, Reijo Keskitalo, Theodore Kisner

CMB observations from ground-based observatories are limited in sensitivity by the fluctuating emission from the Earth's atmosphere, mostly due to water vapor inhomogeneities. Even in atmospheric windows, this spurious signal remains the major source of contamination of the data. Traditional mitigation techniques include low-frequency filtering, or for polarization measurements specifically, modulation with a rotating half-wave plate. The first method filters out a significant fraction of the ta…

詳細を見る →
astro-ph.IMstat.AP

Modeling Dependence Structures in Astronomical Multi-Band Time Series Data via Multi-Output Gaussian Processes

Samata Das, Lishan Shi, Yasaman Hamayouni, Hyungsuk Tak, Jong-Hak Woo

Modern astronomical time-domain surveys routinely collect multi-band light curves that provide complementary information about the physical processes governing source variability. Gaussian processes (GPs) provide a flexible probabilistic framework for modeling irregularly sampled and noisy time-series data. While considerable attention has been devoted to developing covariance kernels for individual time series, comparatively less attention has been paid to the statistical representation of depe…

詳細を見る →
astro-ph.EP

Experimental Measurements of Benzene Ice Critical Saturation Ratios on Titan Tholins and Impact on the Microphysical Modeling of Titan's South Polar Benzene Cloud

David Dubois, Erika Barth, Laura T. Iraci, Ella Sciamma-O'Brien, Farid Salama, Sandrine Vinatier

The Cassini Composite Infrared Spectrometer (CIRS) revealed the presence of a benzene (C6H6) ice cloud in Titan's autumn south polar stratosphere, following the northern spring equinox in August 2009. This event increased the mixing ratio of benzene and raised the cloud top altitude. We present here new experimental measurements of the critical saturation (Scrit) of pure C6H6 ice at low temperature (from 13.8 at 138 K to 3.3 at 157 K), representative of Titan's atmospheric temperatures, when dep…

詳細を見る →
astro-ph.HEastro-ph.COgr-qchep-phhep-th

Ultra-High-Energy Particle Production in Binary Mergers Endowed with Magnetic Fields

Carlos H. Coimbra-Araujo, Rita C. Anjos, Jonas P. Pereira, Jaziel G. Coelho

We study the production of ultra-high-energy particles via the Bañados--Silk--West (BSW) mechanism in the pre-merger phase of binary systems detected by LIGO-Virgo-KAGRA. By solving the geodesic equations for charged particles in magnetized Kerr spacetime with fields of $B \sim 10^{12}$--$10^{14}$~G, we demonstrate that collisions near the horizon can achieve center-of-mass energies $E_{\mathrm{cm}} \sim 10^{18}$-- $10^{20}$~eV, placing them firmly in the ultra-high-energy cosmic-ray (UHECR) ran…

詳細を見る →
astro-ph.HE

Importance and Science Outcomes from the first XSPECT/XPoSat Workshop

Anuj Nandi, Rwitika Chatterjee, V. P. Shyam Prakash, Ankur Kushwaha, M. C. Ramadevi, Kiran M. Jayasurya, Vivek K. Agrawal, M. Varun et al.

This paper summarizes the science outcomes of the first Workshop on Data Analysis using observations from the XSPECT payload onboard the XPoSat, which brought together early-career researchers and experts to explore the instrument's scientific capabilities through lectures and hands-on analyses. Participants performed end-to-end data analysis, including calibration, spectral modeling, and timing studies, on seven sources comprising Neutron Star Low-Mass X-ray Binaries, pulsars, and Black Hole X-…

詳細を見る →
astro-ph.HEastro-ph.SR

Rapid Orbital Decay of Supersoft X-Ray Source WX Cen: a Surrounding Circumbinary Disk

Zhi-Qiang Liu, Wei-Min Liu, Wen-Cong Chen

WX Cen is most likely a candidate of compact binary supersoft X-ray sources, which consists of a white dwarf (WD) and a donor star that fills the Roche lobe. Recently, this source was detected to be experiencing a rapid orbital decay at a rate of $\dot{P} =-(4.4\pm0.4)\times10^{-7}~ \rm days~\rm{yr}^{-1}$. According to the mass function and optical eclipses, the donor-star mass can be constrained to be $0.41-0.44$, $0.47-0.50$, and $0.55-0.59~M_\odot$ when the WD mass is $0.7$, $0.9$, and $1.2~M…

詳細を見る →
astro-ph.EPastro-ph.SR

Magnetohydrodynamical opening of dust traps in protoplanetary disks

Sergey Khaibrakhmanov, Vitaly Akimkin

Observed ring-like structures in protoplanetary disks are often interpreted as local pressure maxima, which induce efficient dust concentration. We revisit this paradigm, considering the effect of the large-scale magnetic field stresses on the gas rotation speed. Our simulations show that the magnetic field can be dynamically strong and cause $1-2$% deviation from the Keplerian rotation at the periphery of a typical turbulent disk with dust grains of size $> 1\,μ$m. This effect increases the inw…

詳細を見る →
astro-ph.IMastro-ph.EP

Detecting habitable exoplanet atmospheres with LIFE, the Large Interferometer for Exoplanets

Sarah Rugheimer, Aiden Weatherbee, James Fecanin, Alistair Glasse, Paul Rimmer, Eleonora Alei, Esther Wang, Marrick Braam et al.

A key goal of astronomers with the next generation telescopes is to detect signs of life in exoplanet atmospheres. NASA's next flagship is the Habitable Worlds Observatory (HWO). In the context of ESA's Voyage 2050 program, the Senior Committee report prioritises detecting habitable exoplanet atmospheres in the mid-IR. The most suited mission for this is the Large Interferometer for Exoplanets (LIFE) which can detect an even wider range of biosignatures than HWO and at lower concentrations. LIFE…

詳細を見る →
astro-ph.HE

Spirited Away: Advective Loss of Cosmic Rays into the Milky Way's Circumgalactic Medium Explains the Large Magellanic Cloud's Low Gamma-ray Luminosity

Taaseen Islam, Hilay Shah, Mark R. Krumholz, Roland Crocker

Models of galactic-scale cosmic ray production and transport have successfully reproduced the radio and $γ$-ray spectra of many galaxies; however, one notable exception is the Large Magellanic Cloud (LMC), where models that successfully fit other galaxies consistently overestimate its $γ$-ray flux. Here we investigate this discrepancy by applying the CRIPTIC cosmic ray transport code to recent magnetohydrodynamic simulations of the LMC's interactions with the Milky Way circumgalactic medium that…

詳細を見る →
astro-ph.SRphysics.plasm-ph

Collisionless stationary states of a stratified plasma in an expanding magnetic tube with stochastic heating

Luca Barbieri, Pascal Démoulin, Daniel Verscharen

We investigate the collisionless kinetic structure of the upper solar atmosphere in the presence of an expanding magnetic field. We consider a stationary two-component plasma confined within an expanding magnetic flux tube and subject to gravity, self-electrostatic interactions, the Pannekoek-Rosseland electric field, and magnetic moment conservation. Starting from the Vlasov equation, we derive fully analytical expressions for the particle distribution functions, density profiles, and the paral…

詳細を見る →
astro-ph.IM

PROVIDENCE: a ground station for space observation

P. -L. Mayeur, J. -F. Sauvage, T. Fusco, N. Védrenne, C. Petit, D. Barbon-Dubosc, G. Leplat, G. Guerrin et al.

PROVIDENCE is an ONERA-led project to install a new-generation optical ground station at the Haute-Provence Observatory (OHP) in South of France. Built around a 2.5-meter aperture, the station addresses five core science cases: space domain awareness, astronomy, laser activities and communications, atmospheric characterization, and instrumental prototyping. The project is organized into three parallel subprojects covering the telescope (Providence T), the building (Providence B), and the instrum…

詳細を見る →
astro-ph.SRastro-ph.GAastro-ph.IMphysics.hist-ph

Echoes of Star Stories: Integrating Indigenous narratives into modern stellar astrophysics

Dionysios Gakis

Indigenous narratives have long preserved observations of celestial phenomena, offering insights that resonate with modern astrophysical research. Deeply embedded in cultural traditions, these stories describe events such as stellar variability, supernovae, eclipses, and planetary alignments. Indigenous communities have also used the stars for navigation and calendar systems, reflecting a sophisticated understanding of celestial patterns. These narratives not only complement historical records b…

詳細を見る →
astro-ph.IM

HARMONI at ELT: optical design of the spectrograph sub-system

Eduard Muslimov, Matthias Teczaa Edgar Castillo-Dominguez, James Kariuki, Liam Bolanda, Miriam Cisneros-Gonzalez, Kieran McCall, Sophie Paszynska

HARMONI is an adaptive optics assisted, near infrared integral field spectrograph for the European Extremely Large Telescope. It covers a spectral range from 750 nm to 2450 nm with resolving powers from 3000 to 7000 and spatial sampling of 25 mas and 6 mas. It can operate in two adaptive optics modes, SCAO and MCAO. The spectrograph represents the last optical sub-system of the HARMONI instrument optical train that disperses the light and forms a two-dimensional spectrogram on its scientific det…

詳細を見る →