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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.IM

Initial modeling and testbed feasibility studies of WaveDriver: a laser guide star AO system for HWO

Dominic F. Sanchez, Benjamin L. Gerard, Peter Waswa, Alex Geringer-Smith, Aditya Sengupta, Alexx Perloff, Michael Messerly, William Moore et al.

The Habitable Worlds Observatory (HWO) will require $>100\times$ greater wavefront stability than achieved by JWST, pushing conventional telescope architectures to picometer-level performance limits. WaveDriver is a mission concept that relaxes these constraints by employing an external laser guide star (LGS) spacecraft flying in formation with HWO to enable wavefront sensing and control. Early results from the High Contrast Testbed demonstrate feasibility of required stability using coronagraph…

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physics.plasm-phastro-ph.SR

Proton Heating Rates in the Inner Heliosphere: Helios Observations

Alaa Fayad, Anna Tenerani, Chadi Salem

Solar wind protons exhibit a temperature anisotropy that deviates from the double-adiabatic prediction, suggesting an additional energy source. To investigate solar wind heating mechanisms, we analyze Helios 1 and 2 data and characterize the radial evolution of the adiabatic invariants and anisotropic heating rates of fast wind protons, considering both the bulk population and its core and beam components separately. Unlike previous studies, we account for proton heat fluxes and deviations from…

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astro-ph.GAastro-ph.CO

The Deep Learning Halo Definer: A Multimodal Framework for Halo Mass and Gas Fraction Inference on Galaxy Groups and Clusters

Caleb Ogle, Kalvyn N. Poncelet Adams, Benjamin D. Oppenheimer, Naomi Gluck, Matthew Ho, Daisuke Nagai, Joseph N. Burchett, Mohammadreza Ayromlou et al.

Accurately inferring dark matter halo properties like the total halo mass (M_{halo}) and gas fractions (f_{gas}) remains particularly challenging at group scales, where low member counts, shallow potential wells, and AGN feedback-driven baryon expulsion introduce significant observational scatter. As large-scale surveys begin to provide unprecedented multi-wavelength data, there is a pressing need for methods that can jointly leverage diverse observables to overcome these uncertainties. We intro…

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astro-ph.SR

Chromospheric sensitivity of stellar spectral lines: an unsupervised machine learning classification

Juan I. Peralta, Mariela C. Vieytes

Stellar magnetic activity alters thousands of spectral lines, limiting high-precision radial-velocity measurements, abundance analyses, and planetary characterization. We present a preliminary classification of 6403 atomic lines in synthetic visible spectra from a sequence of NLTE semi-empirical dG2 atmospheric models with increasing chromospheric heating. Principal-component analysis shows that the dominant component traces overall response amplitude, while the second distinguishes early from l…

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astro-ph.SRastro-ph.EPastro-ph.GA

An Open Cluster Origin for Most Solar-Type Binaries in the Solar Neighborhood and Implications for Primordial Planet Stability

Anna C. Childs, Aaron M. Geller

We present the first Gaia-calibrated estimate of the contribution of dynamically processed open clusters (OCs) to the nearby solar-type field binary population and investigate the implications for primordial planet stability. We combine Gaia DR3 observations, empirical models of cluster formation and dissolution, and direct N-body simulations to constrain the fraction of field FGK-type binaries within 1 kpc that originated in OCs over the past 5 Gyr. We find that at least ~53% of solar-type fiel…

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astro-ph.SRastro-ph.GAastro-ph.HE

Inflated Supermassive Stars as Little Red Dots and Progenitors of Supermassive Black Holes

Wenbin Lu

JWST has uncovered an abundant population of compact, red sources at high redshifts, termed little red dots (LRDs). We study whether they could be explained by thermally relaxed, hydrogen-burning, metal-enriched supermassive stars (SMSs). We construct 1D models in hydrostatic and thermal equilibrium, including a radiation-pressure-dominated, CNO-burning core and an outer envelope with metallicity-dependent opacity, non-adiabatic convection, and an effective treatment of super-Eddington surface l…

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astro-ph.SR

The Last Gasps of a Dying Star: ALMA Observations of the Pre-Planetary Nebula IRAS 06530-0213

Raghvendra Sahai, Wouter Vlemmings, Guillermo Quintana-Lacaci, Hyosun Kim, Javier Alcolea, Bruce Balick, Eric G. Blackman, Arancha Castro-Carrizo et al.

We present high angular-resolution ($\sim 0.{''}1 - 0.{''}5$) ALMA observations of millimeter-wave line and continuum emission (at $\sim0.44$ and $0.88$ mm) in the pre-planetary nebula IRAS 06530--0213 (IRAS 06530). These data show the presence of an extended circular ring -- first evidence of the last thermal-pulse preceding the post-AGB phase in a carbon star -- and a central bipolar nebula (CBN) and torus. The mass-loss rate of IRAS 06530's AGB progenitor decreased immediately after the therm…

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astro-ph.GA

CECILIA: Using Flexible Photoionization Models to Accurately Measure Abundances without Auroral Lines

Nathalie A. Korhonen Cuestas, Allison L. Strom, Yijia Li, Noah S. J. Rogers, Caroline von Raesfeld, Gwen C. Rudie, Ryan F. Trainor, Menelaos Raptis et al.

JWST has facilitated the detection of faint, auroral emission lines needed to directly measure the electron temperature and elemental abundances in high-redshift galaxies. However, such measurements still require substantial observational investment, potentially making self-consistent, population-level studies of direct-method metallicity scaling relations across multiple epochs of Cosmic time prohibitively expensive. Photoionization modeling could allow us to measure metallicity using more rout…

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astro-ph.HE

Importance of the Resonant Cosmic-Ray Streaming Instability Upstream of Collisionless Shocks

Bricker Ostler, Benedikt Schroer, Damiano Caprioli

Cosmic rays (CRs) escaping collisionless shocks form a dilute, relativistic population whose current amplifies the upstream magnetic field, a process widely attributed to the non-resonant (Bell) instability. Solving the dispersion relation for both cold and finite-spread CR distributions, we show that for the maximum-energy escaping population, the resonant mode can outgrow the non-resonant mode. At slower shocks, this dominance persists for broader CR distributions, and sufficient pitch-angle b…

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astro-ph.EPphysics.geo-ph

Tectonics on early Earth driven by Earth's changing shape during tidal recession of the Moon

Simon J. Lock

Few fragments of Earth's earliest crust have survived, and so this formative period of our planet's history is shrouded in mystery. To leverage the limited data available, it is important to understand all the processes that could have shaped our young planet. Here, I explore a previously neglected aspect of early-Earth dynamics: rotation. Earth after the Moon-forming impact was rapidly rotating with its rotation rate slowing significantly during the first tens of millions of years after the imp…

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astro-ph.SR

The "Other" Centuries-Long Record of Solar Magnetic Activity Cycles: Lessons From the Stars

Jason T. Wright, Travis S. Metcalfe, Kristof Petrovay, Hisashi Hayakawa

Studies of space climate and solar magnetic activity and studies of stellar dynamos and magnetic cycles are separated by discipline and by the quality of the data we have to work with: the Sun gives us detailed knowledge of a single star, while the stars give us comparatively sparse data across a range of (sometimes poorly known) masses and ages. This review, a collaboration among scientists with expertise in stellar astronomy, space climate, and solar physics, seeks to provide a guide to what t…

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astro-ph.COastro-ph.GA

Model-Independent Measurement of Baryon Gas Fractions through Galaxy-Galaxy Lensing and the Kinematic Sunyaev-Zel'dovich Effect

R. Henry Liu, Uroš Seljak, Simone Ferraro, Boryana Hadzhiyska, Frank J. Qu, Bernardita Ried Guachalla, Emmanuel Schaan, Jessica Nicole Aguilar et al.

Baryon feedback is a leading source of systematic uncertainty for cosmology from weak lensing, but measurements of the gas distribution around galaxies have largely relied on parametric profile models or simulation-calibrated frameworks. We present model independent measurements of the radial gas fraction profile around galaxies, combining galaxy-galaxy lensing and kinematic Sunyaev-Zel'dovich (kSZ) effect. We introduce a method that applies the same radial $ΔΣ$ aperture filter to both the galax…

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astro-ph.GAastro-ph.CO

The ALMA View of High-Redshift Galaxy Formation

Renske Smit, Rebecca A. A. Bowler

The advent of routine operations with the Atacama Large Millimeter/submillimeter Array (ALMA) in the last decade has led to a revolution in the direct study of the interstellar medium (ISM) in `normal' high-redshift galaxies in the rest-frame far-infrared (FIR). This review summarizes the observational literature on z>6.5 sources observed with ALMA and NOEMA (NOrthern Extended Millimeter Array). The main findings are as follows: Cool gas consistently scales with star-formation in a wide range of…

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nucl-thastro-ph.HEhep-ph

Evidence for a Continuous Hadron--Quark Transition in Cold Dense Matter

Yong-Jia Huang, Bikai Gao

Statistical evidence for a continuous hadron-quark transition is found in this work. Confronting microscopic descriptions connecting the Parity Doublet Model and the Nambu--Jona-Lasinio model with observationally constrained non-parametric equations of state, Bayesian model comparison decisively favors a boundary-free crossover over the conventional first-order Maxwell construction ($Δ\ln\mathcal{Z} \sim +7.20$) and fixed-boundary crossover ($Δ\ln\mathcal{Z} \sim +5.16 $). The preferred crossove…

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astro-ph.GAastro-ph.HE

LoTSS of dual AGN: enhanced detectability and prospects for a systematic search

Q. D'Amato, F. Mannucci, E. De Rubeis, I. Prandoni, A. De Rosa, M. Scialpi, M. Kunert-Bajraszewska, A. Janiuk et al.

Context: Dual active galactic nuclei (DAGN) - systems of two accreting supermassive black holes at kpc-scale separations - trace galaxy mergers and are the progenitors of gravitational-wave sources targeted by pulsar timing arrays and the upcoming Laser Interferometer Space Antenna. However, their radio properties remain poorly constrained, particularly at high redshift. Aims: We demonstrate the detectability of high-redshift DAGN at 144 MHz through sub-arcsec imaging of the LOFAR Two-metre Sky…

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astro-ph.SRastro-ph.HEgr-qc

Super-Chandrasekhar white dwarfs by the evolution of magnetized main-sequence stars: New mass-limits from STARS simulation

Zenia Zuraiq, Banibrata Mukhopadhyay, Achal Kumar, Arnab Sarkar, Alexander J. Hackett, Projjwal Banerjee, Christopher A. Tout

We explore the time evolution of the magnetized main-sequence stars (MSs) to magnetized non-rotating white dwarfs (WDs) with a series of models, capturing modified Hertzsprung-Russell diagram. We use the Cambridge Stellar evolution code, STARS, with modifications by introducing magnetic effects and cooling. We investigate the possible existence of stable, magnetized, massive, super-Chandrasekhar, approximately spherical WDs, away from Chandrasekhar's mass-radius curve. These we refer to as B-WDs…

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astro-ph.GA

Low-power jet-ISM coupling and disk-plane perturbations in the edge-on Seyfert galaxy NGC 4388

M. Ceci, G. Venturi, C. Marconcini, M. V. Zanchettin, G. Cresci, M. Tartėnas, K. Zubovas, E. Treister et al.

Active galactic nuclei (AGN) may regulate galaxy evolution through radiatively driven winds and collimated jets, but their relative impact and coupling to the interstellar medium (ISM) remain uncertain. We investigate the ionized gas in the nearby ($D\sim$ 17 Mpc) Seyfert 2 galaxy NGC 4388, hosting a galaxy-scale ($\sim$1.6 kpc), low-power ($\sim1.4~\times~10^{42}~erg~s^{-1}$) bipolar radio jet projected roughly perpendicular to its edge-on disk. We analyze optical integral-field spectroscopic o…

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astro-ph.GAastro-ph.HE

Galaxy-SMBH co-evolution in 2,435 DESI disk galaxies and merger-free BH growth in bulgeless disks

Sophie M. Jewell, Rebecca J. Smethurst, Chris J. Lintott, Brooke D. Simmons, Ricarda S. Beckmann, Izzy L. Garland, Tobias Géron, Benne W. Holwerda et al.

We analyse black hole scaling relations for disk-dominated galaxies, and present evidence for secularly driven galaxy-black hole co-evolution. We do this observationally by looking at ``bulgeless'' galaxies, where the lack of a stellar bulge suggests a quiet merger history. We first compose a sample of 2,435 disk-dominated galaxies hosting optical broad line active galactic nuclei (AGN) from DESI data, and find a $M_{\mathrm{BH}}$--$M_{*}$ scaling relation of $\log(M_{\mathrm{BH}})= - 3.7^{+0.3}…

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astro-ph.GA

Direct imaging of sub-parsec binary SMBHs in the central galaxy of the NGC 5044 group

Francesco Ubertosi, Gerrit Schellenberger, Ewan O'Sullivan, Laurence P. David, William Forman, Simona Giacintucci, Christine Jones, Kamlesh Rajpurohit et al.

Binary active galactic nuclei (AGN) consist of two supermassive black holes (SMBHs) hosted in a single galaxy that are simultaneously accreting gas. These systems are key to understanding hierarchical galaxy evolution and represent prime targets for low-frequency gravitational wave (GW) experiments. However, binary AGN remain extremely rare: only a handful are confirmed at separations of a few hundred parsecs, and just one pc-scale binary - in an elliptical galaxy at the center of a galaxy clust…

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astro-ph.GA

Dual Signatures of Bursty Star Formation in High-Redshift UV Luminosity Functions

Guochao Sun, Claude-André Faucher-Giguère, Steven R. Furlanetto, Adam Lidz

The UV luminosity function (UVLF) encodes key information about galaxy formation. The slowly evolving bright-end UVLFs at $z\gtrsim10$ have made UV variability from bursty star formation a promising explanation, but the impact of such variability need not be restricted to the bright end. Motivated by ultra-deep measurements of the $z\simeq7$ UVLF, we investigate whether UV variability can provide a unified interpretation of the low-mass star formation efficiency (SFE) at $z\simeq7$ and the abund…

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astro-ph.SRastro-ph.HE

A Quantitative Method to Investigate the Spectral Class Time Evolution of Novae

Maria Kopsacheili, Martín Guerrero, Diego Alejandro Vasquez Torres

Novae are spectroscopically classified as Fe II or He/N according to the dominance of Fe II, or He and N emission lines in their pre-nebular spectra, while spectra exhibiting both are classified as hybrid. Evidence suggests that these spectral classes represent spectral evolution. We investigate this scenario using a large spectroscopic dataset and introduce a quantitative coefficient, $κ$, to characterise the relative strength of Fe II and He/N emission. The coefficient is defined as the ratio…

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astro-ph.IM

Probing Millisecond Optical Timescales with Continuous-Readout Mode Observations from ZTF

Shar Daniels, Federica Bianco, Igor Andreoni, Ashish Mahabal, Rich Dekany, Gregory Dobler, Matthew Graham, Roger Smith et al.

The subminute-timescale phase space is an underexplored regime of the optical sky. Sub-second optical observations are difficult to accomplish with traditional CCD exposure-readout cycles, and alternative technologies like EMCCDs and CMOS have historically limited surveys to targeted observation. Continuous-readout mode enables millisecond-timescale observations on traditional cameras by leaving the shutter open during readout, enabling high-cadence observations on all-sky surveys. We present th…

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astro-ph.GA

Star Formation and Nebular Attenuation from Pa$α$, Br$α$, and Br$β$ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST

Virginia Vanicek, Jed McKinney, Alexandra Pope, Anna Sajina, Stacey Alberts, Meredith Stone, Lee Armus, Sinclaire M. Manning et al.

Near-infrared hydrogen recombination lines can provide robust star-formation rates if the effects of dust attenuation continue to diminish towards longer wavelengths. To quantify near-infrared attenuation and ultimately measure accurate star-formation rates (SFRs) at the height of cosmic star-formation, we present Pa$α$, Br$α$, and Br$β$ detections in $27$ luminous infrared galaxies at $z\sim 1-2$, including pure star-forming galaxies as well as dust-obscure Active Galactic Nuclei (AGN). Using c…

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astro-ph.HE

GRB 220706A: a gamma-ray burst with a month-long engine and a luminous supernova

Benjamin P. Gompertz, Nusrin Habeeb, Dheeraj R. Pasham, Antonio de Ugarte Postigo, Daniele B. Malesani, Phil A. Evans, Kim L. Page, Ben Rayson et al.

While the progenitors of many long gamma-ray bursts (GRBs) are well established as the core collapse of very massive, envelope-stripped, rapidly-rotating stars, it has been suggested that bursts at the extremely long end of the duration distribution may be a separate population of `ultra-long' GRBs. With durations of thousands of seconds or more, these bursts are difficult to reconcile with the engine timescales expected from the compact Wolf-Rayet stars that are typically assumed to produce mor…

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astro-ph.GA

Linking X-ray emission to galaxy populations in GAMA groups

Selene Levis, Hernán Muriel, Valeria Coenda, Andrea Biviano, Héctor J. Martínez, Martín de los Rios

We study how the presence of a detectable hot intragroup medium affects galaxy colour and star-formation properties, and how these trends depend on dynamical stage within the group. We analysed galaxies in GAMA groups with and without X-ray detection (XG and NXG) at 0.1 <= z <= 0.2, using samples with similar halo-mass distributions, compared with a field control sample. Galaxies were classified as red, green, or blue by UV-optical colour, and group galaxies further classified into dynamical cla…

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astro-ph.HEastro-ph.GA

Geometrically Thin Sub-Eddington AGN Accretion Disks show a suppressed Lyman Edge

Ish Kaul, Yan-Fei Jiang, Omer Blaes, Lizhong Zhang

The observed ultraviolet continua of active galactic nuclei (AGN) generally lack a strong intrinsic HI Lyman edge predicted by classical optically thick accretion disk atmosphere models. We revisit this long-standing problem using our previous sub-Eddington ($L/L_{\rm Edd}\sim 0.03$) geometrically thin 3D accretion disk simulation evolved with gray angle-dependent radiation magnetohydrodynamics (MHD) around a $10^8M_{\odot}$ black hole. This disk is magnetic pressure dominated, and has surface d…

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astro-ph.GA

Multi-tracer constraints on quasar outflows. Acceleration from BLR to galactic scales

M. Brazzini, M. Bischetti, S. Hagen, V. D'Odorico, N. Arav, G. Becker, G. Cupani, F. Fiore et al.

Black hole-driven outflows are a fundamental component of the Active Galactic Nuclei (AGN) paradigm, and may play a major role in regulating the evolution of both supermassive black holes and their host galaxies. Yet, their physical properties remain challenging to constrain, due to their multi-phase and multi-scale nature which demands a combined approach of different complementary observational tracers. In this work, we investigate AGN-driven ionized outflows from nuclear to galaxy scale withi…

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astro-ph.GAastro-ph.HE

The AGN Channel in 3D: Scattering Belts and the Importance of Eccentricity in the Black Hole Population

Connar Rowan, Martin E. Pessah

Active galactic nuclei (AGN) are a promising origin for observed gravitational wave mergers. Current population synthesis models are limited to 1D N-body or Monte Carlo methods which rely on statistical approaches to resolving dynamical scatterings. We present three-dimensional hybrid $N$-body simulations of a population of black holes (BHs) surrounding an AGN using a new code in development, AGNBI, where close interactions are directly simulated for both single and binary objects. Our results s…

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astro-ph.SRastro-ph.EP

Multi-Epoch Stability in the Rotational Modulation of the Planetary-Mass Companion Ross 458C

Elena Manjavacas, Jared Bull, Paulo Miles-Paez, Natalia Oliveros-Gomez, Theodora Karalidi, Ben W. P. Lew, Zhoujian Zhang, Yifan Zhou et al.

Spectroscopic variability is detected in brown dwarfs across all spectral types, suggesting atmospheric patchiness in brown dwarf atmospheres. We present JWST/NIRSpec time series observations of the T8.0 planetary-mass companion Ross 458C. We compared our derived spectral variability and light curve to those obtained using HST/WFC3 observations more than 7.5 yr before and published by Manjavacas et al. (2019). We found that the light curve of Ross 458C is remarkably similar in the two epochs in…

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astro-ph.GA

Discovery, Characterization, and Potential Origins of a Stream in the Stellar Halo of Nearby LMC-Mass Galaxy NGC 55

Benjamin N. Velguth, Burçin Mutlu-Pakdil, Erik Tollerud, Sarah Pearson, Kristine Spekkens, Amandine Doliva-Dolinsky, Michael G. Jones, Denija Crnojević et al.

We present a previously undetected stellar stream in the halo of the LMC-mass dwarf galaxy NGC 55 (2 Mpc), as part of an ongoing effort to characterize the stellar halos of LMC/SMC-mass dwarfs in the DEEP component of the DECam Local Volume Exploration (DELVE) survey. This structure is aligned with an outflow traced by H$α$ emission, a spur and cloud of neutral hydrogen, and the ultra-diffuse and possibly disrupting satellite galaxy NGC 55-dw1. We investigate possible ex-situ progenitor scenario…

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