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Research Trends

Latest preprints in space engineering and astrophysics.

gr-qcastro-ph.IM

A Multipole Technique for the Simulation and Analysis of Gravitational Waveforms from Extreme Mass Ratio Inspirals

Courtney McIntosh, Jeremy Schnittman

We introduce EMRICode, a Python-based numerical framework for evolving generic extreme mass-ratio inspirals (EMRIs) in Kerr spacetime. The code combines adaptive numerical integration of test-particle geodesics with a prescribed model for the secular evolution of the orbital constants of motion, allowing eccentric and inclined trajectories to be followed over long inspiral timescales. We focus in particular on the treatment of the Carter constant, whose evolution is not directly determined by th…

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astro-ph.EPcond-mat.mtrl-scics.LGphysics.chem-phphysics.geo-ph

Ammonia-Hydrogen Phase Equilibria in Planetary Envelopes from First-Principles-Based Machine-Learning Molecular Dynamics

Akash Gupta, Austin Guo, Jie Deng

Ammonia and hydrogen are major constituents of planets within and beyond the solar system, yet how they interact in planetary envelopes is poorly known. We perform large-scale two-phase coexistence simulations of the ammonia-hydrogen system from 500 to 4000 K and 0.1 to 100 GPa, driven by machine-learning interatomic potentials trained on density functional theory calculations. From these we map the compositions of coexisting hydrogen-rich and ammonia-rich phases, and the critical curve that sep…

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astro-ph.HEastro-ph.IM

Twenty-five years of XMM-Newton EPIC-MOS2 Unfocused Particle Background: Solar Cycle Modulation, Galactic Cosmic-Ray Correlation, and Implications for NewAthena

B. Vaia, F. Gastaldello, S. Molendi, I. Bartalucci, M. Balboni, S. Ghizzardi, L. Lovisari, M. Marelli et al.

We present a study of the unfocused particle-induced background measured by the XMM-Newton EPIC-MOS2 detector, extending previous analyses to the end of 2025 and covering approximately twenty-five years of observations. Using out-of-field-of-view (outFOV) data, we investigate the long-term evolution of the particle background over two complete solar cycles and compare it with independent tracers of the Galactic cosmic-rays. We find an extremely tight correlation between the MOS2 outFOV count rat…

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astro-ph.SRastro-ph.GA

20,000 Rotation Periods in Nearby Open Clusters and Moving Groups from ZTF and ASAS-SN

Yuxi Lu

Open clusters provide uniquely powerful laboratories for studying stellar evolution because their members share a common age and chemical composition. Stellar rotation of low-mass GKM dwarfs in open clusters provides direct empirical constraints on magnetic braking, with implications for stellar interiors, magnetic activity, and star--planet interactions. However, existing cluster rotation samples are dominated by space-based observations, whose limited spatial coverage and short observing basel…

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astro-ph.SR

Slowly Rotating Fully Convective Stars at $\lesssim$ 1 Gyr: Evidence from the Hyades and Praesepe

Yuxi Lu, Marc H. Pinsonneault, José G. Fernández-Trincado, Richard R. Lane, Alexandre Roman-Lopes, Keivan G. Stassun, Emily K. Pass, Guy S. Stringfellow et al.

We report the discovery of 10 stars in the Praesepe and Hyades clusters with unusually slow rotation that are likely not field contamination. Even though our search was general, all slow rotators are in the fully convective domain. We find that the fraction of slow rotators in the clusters is more than $5σ$ above the distribution expected from field contamination. They provide a potential link between the period distribution of the young open clusters and the field. These stars could be a distin…

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astro-ph.GAastro-ph.CO

Leviathan: a very massive, extended sub-millimetre galaxy spectroscopically confirmed at $\rm z = 4.05$

William M. Baker, Francesco Valentino, Jens Hjorth, Gabriel Brammer, Ugnė Dudzevičiūtė, Kei Ito, Antonio Pensabene, Pengpei Zhu et al.

We present Leviathan, a sub-millimetre galaxy (SMG) spectroscopically confirmed at $z=4.051$ with JWST/NIRSpec. Modelling 31 bands of photometry from the rest-frame ultraviolet to the millimetre, we find a stellar mass of $\log(M_\star/M_\odot)=11.34^{+0.15}_{-0.22}$, making Leviathan one of the most massive spectroscopically confirmed galaxies at $z>4$, yet consistent with $Λ$CDM for a star-formation efficiency of approximately 20%. Although SMGs are often thought to be building the dense cores…

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astro-ph.GA

The SIMPLIFI Survey: Polarization of Dense Filaments with SOFIA III. Relative orientations of antenna temperature gradients with the magnetic field in the DR21 molecular cloud

Mark Heyer, Thushara G. S. Pillai, Jens Kauffmann, Juan D. Soler, Daniel Seifried, Laura M. Fissel, Gabriel A. P. Franco, Paul F. Goldsmith et al.

We investigate magnetohydrodynamic (MHD) turbulence in the DR21 molecular cloud using far infrared polarimetry from SOFIA HAWC+ and molecular spectroscopy from the Nobeyama 45~m telescope. The Velocity Channel Gradient (VChG) method is applied to thin velocity slices of the 12CO and 13CO J=1-0 emission to determine the antenna temperature gradients and their orientations in the plane of the sky. The relative orientations of the gradients with respect to the magnetic field position angles enable…

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hep-phastro-ph.COastro-ph.GA

Self-interacting dark matter from radiative bound-state-formation feedback

Marcos M. Flores, Kalliopi Petraki, Thomas Pignard

Observations of galactic structure motivate sizable dark-matter self-interactions at low velocities, naturally realized through light force mediators. Such mediators can also make inelastic processes very efficient. Unitarity then requires their absorptive contributions to the two-particle self-energy kernel to be resummed, which in turn feeds back into both the elastic and inelastic scattering amplitudes. We study the feedback of radiative bound-state formation on elastic scattering and its imp…

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astro-ph.GA

Dual and lensed AGN at sub-arcsecond separations uncovered by ERIS

M. V. Zanchettin, F. Mannucci, Q. D'Amato, M. Scialpi, C. Marconcini, G. Tozzi, E. Bertola, A. Feltre et al.

We present the first results of the ongoing INAF GTO program focused on the search of sub-arcsecond dual AGN, carried out with the near-infrared integral-field unit SPIFFIER of the Enhanced Resolution Imager and Spectrograph (ERIS) at the ESO Very Large Telescope, operating in adaptive-optics mode with a laser guide star. We report integral field spectroscopy with the low-resolution gratings (R ~ 5000 - 5600) of 34 multiple AGN candidates selected from the Gaia Data Release 3 source catalog via…

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astro-ph.HE

A Unified Model for the Gravitational Wave Background and Quasar Luminosity Functions

Cayenne Matt, Kayhan Gültekin, Ryan Hickox

The supermassive black hole mass function (BHMF) is a necessary ingredient in our understanding of how BHs grow and evolve with their host galaxies. Estimations of the BHMF based on observations of local BHs, quasars, and gravitational wave data yield inconsistent results, leading to large uncertainties in, e.g., BH accretion and seeding models. The nanohertz gravitational wave background (GWB) has been a powerful tool to provide constraints on the BHMF across cosmic time. We take posterior BHMF…

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astro-ph.HEastro-ph.COastro-ph.IMastro-ph.SRgr-qc

Localizing binary neutron stars with the Einstein Telescope: a full Bayesian comparison of the triangular and 2L configurations

Filippo Santoliquido, Jacopo Tissino, Marica Branchesi, Ulyana Dupletsa

The Einstein Telescope (ET), the European next-generation gravitational-wave observatory, is at a decisive stage: the choice of its detector configuration is still open, with profound implications for its scientific output. We provide a quantitative basis for this choice by comparing two candidate configurations at their proposed sites: the triangular design ($Δ$) at the Euregio Meuse-Rhine site, and the 2L design, with interferometers in Sardinia, Italy, and Lusatia, Germany. We present the fir…

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astro-ph.GAastro-ph.COastro-ph.HE

Optical and Ultraviolet Emission from the Gas Photoionized by Gaia BH3: Archival Constraints and Predictions for the 2029 Periastron

Nico Cappelluti, Fabio Pacucci

Gaia BH3, a $32.7\,M_\odot$ black hole (BH) on an 11.6-yr, $e=0.73$ orbit around a metal-poor giant at $\approx590$ pc, accretes from its wind. Neither its mass-loss rate $\dot M_{\rm w}$ nor the fraction of captured gas reaching the BH is known. We ask whether optical and ultraviolet lines from gas photoionized by the hot flow are observable and what they reveal. Unlike X-ray and radio data, they count the ionizing photons the gas absorbs and trace its density and velocity. With Cloudy we compu…

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astro-ph.HEastro-ph.GA

Balmer breaks in accreting super-massive black hole binaries

Christopher Tiede, Zoltan Haiman

We show that truncated circumbinary accretion disks around super-massive black hole binaries can produce Balmer breaks. For binaries interacting with surrounding disks in a truncated, non-accreting phase, gas accumulates at the cavity edge, and can create conditions conducive to generating spectral discontinuities from $n=2$ hydrogen bound-free absorption. We develop a simple model for predicting the presence of a Balmer edge and estimating the break strength, and we find that the strongest disc…

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gr-qcastro-ph.IMphysics.data-an

Deglobalising the fit: how to search for physics beyond vacuum General Relativity in LISA catalogues

Francisco Duque, Jonathan Gair

The Laser Interferometer Space Antenna will observe up to $\sim 10^{7}$ overlapping signals, which have to be characterised simultaneously with a global fit. This is a challenge for model comparison since rerunning the global fit for every physical model of interest, including deviations from vacuum General Relativity, is computationally demanding. An alternative is a two-step post-processing strategy: a first global fit with vacuum models only, after which a selected group of target sources is…

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astro-ph.EP

Beyond static torques: Self-consistent migration and dynamical trapping of low-mass planets in dusty disks

Jose L. Gomez, Pablo Benitez-Llambay, Ximena S. Ramos, Octavio M. Guilera

The rapid inward migration of low-mass planets remains a primary theoretical challenge in planet formation. While recent studies show that the solid component of protoplanetary disks can exert strong positive torques to counteract the negative gas torques, traditional static fixed-orbit models fail to capture the fully coupled dynamics of a migrating planet. In this work, we present 2D high-resolution, two-fluid hydrodynamical simulations using a comoving reference frame to track the self-consis…

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astro-ph.EP

Small Collisions, Big Impact: The Sensitivity of Atmospheric Temperatures to Collision-Induced Absorption

David Dahlbüdding, Tommaso Grassi, Karan Molaverdikhani, Giulia Roccetti, Barbara Ercolano, Paola Caselli

Collision-induced absorption (CIA) data are relevant to determining atmospheric temperatures and, in turn, the habitability of a diverse set of planetary atmospheres. However, these data remain sparse across broad wavelength and temperature ranges. Nevertheless, multiple, sometimes disagreeing, sources of experimental and theoretical data can be available for the same CIA pair. In this paper, we assess the impact of these varying sources on atmospheric temperatures and the limitations that the a…

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astro-ph.GA

Metal-poor molecular clouds in dwarf galaxies at parsec-scale resolution

L. K. Hunt, M. Heyer, U. Lisenfeld, A. Weiss, A. Bolatto, E. Brinks, M. Rubio, D. Calzetti et al.

Understanding how stars form at low metallicity is challenging because carbon monoxide (CO) emission, which usually probes the molecular gas reservoir, is faint, and tends to be concentrated in parsec-scale clumps. To overcome this difficulty, in order to study the molecular clouds in metal-poor environments, we have acquired CO(2-1) ALMA maps at 3-4 pc resolution of four nearby dwarf galaxies with nebular (O/H) metallicities ranging from roughly 1/9 Z_sun to 1/3 Z_sun. Significant CO signal in…

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astro-ph.EPastro-ph.SR

Planets surviving common envelope evolution should be rare, massive, and orbit very close to their host star

Yadira S. Gaibor, Andrew Vanderburg, Juliette C. Becker, Melinda Soares-Furtado, Saul Rappaport, Tansu Daylan

The discovery of exoplanets around white dwarfs uniquely informs our understanding of planetary survival through stellar evolution. Common Envelope (CE) evolution is one of the proposed mechanisms that could shape the orbital architecture of these planets around stellar remnants. In this work, we predict the occurrence rate and orbital separation/planet mass distributions for planets that could form around white dwarfs through CE evolution. We simulate populations of giant-planet systems, sampli…

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astro-ph.GA

The ALMA REBELS Survey: The [C II] Luminosity Function of UV-Selected Galaxies at $z\sim7$

Thomas Herard-Demanche, Pascal A. Oesch, Rychard Bouwens, Jacqueline A. Hodge, Hiddo S. B. Algera, Manuel Aravena, Karin Cescon, Elisabete da Cunha et al.

Luminosity functions (LF) are some of the most basic quantities providing insights into galaxy evolution across cosmic time and enabling a direct comparison between observations and simulations. Here, we present the first [CII]158$μ$m LF at $z\sim7$ from a sizeable UV-selected ALMA sample. Our analysis makes use of 27 galaxies with significant [CII] emission line detections in the epoch of reionization from the REBELS (Reionization Era Bright Emission Line Survey) ALMA Large Program and its pilo…

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hep-phastro-ph.COastro-ph.GA

Annihilation feedback on elastic scattering in self-interacting dark matter

Kalliopi Petraki, Thomas Pignard

Sizable dark-matter self-interactions, motivated by observations of galactic structure, often arise from the exchange of light force mediators. Light mediators can render scattering nonperturbative and make inelastic processes important. Unitarity, via the optical theorem, implies that elastic and inelastic interactions cannot be treated independently: inelasticity induces absorptive contributions to the two-particle self-energy kernel that determines the elastic amplitude, while the resulting i…

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astro-ph.IMastro-ph.COastro-ph.GAcs.LG

Graph Neural Networks for Astrophysics and Cosmology

Christian Kragh Jespersen

Physics seldom makes breakthroughs when we consider objects only in isolation. Instead we model and measure how objects sit among their neighbours, spatial, temporal, or otherwise: a galaxy in its environment, a halo in its history, a photon hit in a detector. Graphs are ideally suited for encoding exactly these relations, and Graph Neural Networks (GNNs) learn the geometric functions that respect them. This review presents the use of GNNs for astrophysics and cosmology, and argues that GNNs oft…

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astro-ph.GA

How does a galaxy's quenching probability depend on its black hole's mass?

Antonio J. Porras-Valverde, John C. Forbes

We develop a parametric toy model to explore how black hole mass scatter $σ_{\rm BH}$ and the dependence of the quenching probability per unit time on black hole mass, parameterized as a power law with index $q$, jointly control the faint-end slope $α$ of the stellar mass function of quenched central galaxies. By varying $σ_{\rm BH}$ and $q$, we identify two regimes. At low scatter, $σ_{\rm BH} \lesssim 0.4$ dex, $α$ is strongly sensitive to $q$. Gradual quenching, represented by low $q$, produc…

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astro-ph.GA

Low-mass and High-sSFR H$α$ Emitters at $z \sim 2$ in the ZFOURGE-COSMOS Field

Jeung Yun, Kentaro Motohara, Kosuke Kushibiki, Nuo Chen, Masahiro Konishi, Hidenori Takahashi, Tomoya Yukino, Shuhei Koyama et al.

We present a near-infrared spectroscopic follow-up study of seven H$α$ emitter candidates at $z\sim2$ in the ZFOURGE-COSMOS field, selected via the $K_{\rm s}$-band flux excess method. Spectra obtained with Subaru/SWIMS confirm strong H$α$ emission line at $z=2.06-2.49$ for all the targets. Three galaxies are low-mass systems ($\log(M_\star/M_\odot) 10$) on the star-forming main sequence. The low-mass galaxies show consistent H$α$ flux measurements between the $K_{\rm s}$-band flux excess method…

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astro-ph.IMastro-ph.EP

The science case for an in-situ measurement platform in the Venus clouds

Maureen Cohen, Joanna Egan, Martin Airey, Karen Aplin, Gilles Bailet, Paul Byrne, Chris Castelli, Charles Cockell et al.

The next step for Venus exploration after the remote sensing missions of the early 2030s will be in-situ aerial platforms, the Venus equivalent of rovers for Mars. Sophisticated Venus balloon technology is already under development and presents an opportunity for the United Kingdom to act as a bilateral partner in missions exploring key questions about the volcanic and geological history of Venus, the potential habitability of the Venus clouds, and Venus as an analogue for exoplanets. White pape…

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astro-ph.HE

X-ray Comptonization in an Accreting Kerr Black Hole System with a Tilted Disc and Thermal Corona; A General-Relativistic Monte Carlo Simulation: I. Model, Radiative Transfer and Spectral-Timing Properties

Mainak Chatterjee, Dipankar Bhattacharya

Quasi-periodic oscillations (QPOs) in the X-ray emission of accreting black hole binaries are commonly attributed to the relativistic Lense--Thirring precession of the inner accretion flow, in which a hot inner flow, tilted with respect to the black hole spin axis, precesses as a solid body while a cooler outer disc remains at its own, different tilt -- a warped, Bardeen--Petterson-type geometry. Testing this picture requires a radiative-transfer model that self-consistently follows photons thro…

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physics.plasm-phastro-ph.HE

Ion Heating in Pair-loaded Relativistic Turbulence

Yusen Wang, Zhonghai Zhao, Xinyu Zhu, Xianxu Jin, Zhipeng Zhang, Bin Qiao

Pair-loaded relativistic turbulence is expected in compact high-energy astrophysical environments and may sustain plasma heating. Using self-consistent three-dimensional radiative particle-in-cell simulations, we identify the mechanism of ion heating mediated by pair-enhanced radiative feedback in relativistic turbulence. We derive the theoretical criterion for the transition to a regime dominated by radiative feedback and show that pair loading promotes the growth and persistence of large, conn…

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astro-ph.HE

Deep X-ray Observations of the Gamma-ray Bright Pulsar Wind Nebula HESS J1303-631

Seth Gagnon, Oleg Kargaltsev, Yichao Lin, Jeremy Hare, Jordan Eagle

HESS J1303$-$631 is an evolved, TeV-bright pulsar wind nebula (PWN) powered by the energetic radio pulsar PSR~J1301$-$6305, offset by $\approx7'$ northwest of the TeV centroid, with an energy-dependent gamma-ray morphology. We present new, deep joint Chandra (108 ks) and XMM-Newton (102 ks) observations of this field. High-resolution Chandra ACIS imaging resolves the pulsar from a neighboring point source that XMM-Newton cannot separate. The pulsar's 2-10 keV spectrum is well described by an abs…

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astro-ph.HE

Detection Forecasting for Blazars at MeV Energies with Fermi-LAT Swift-BAT Cross Match

Timothy Wessling-Resnick, Naomi Tsuji, Tsuguo Aramaki, Paolo Coppi, Manel Errando, Yoshiyuki Inoue, Reshmi Mukherjee, Svanik Tandon et al.

Over the past two decades, the lack of an MeV $γ$-ray all-sky instrument has left an observational gap in blazar broadband emission. Recently, a new suite of MeV $γ$-ray instruments with sensitivity in the $10^{-11}$ to $10^{-12}$ $\mathrm{erg/cm^{2}/s}$ range has been proposed, with the potential to far surpass the capabilities of previous all-sky MeV instruments. In this work, we forecast the capabilities of future MeV $γ$-ray instruments including COSI, GRAMS, newASTROGAM, and AMEGO-X to obse…

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hep-phastro-ph.HE

Dark Matter Interpretations of the Galactic Center Gamma-Ray Excess with 18 Years of Fermi-LAT Data and the FL16Y Source Catalog

Sang Hwan Kim, Hae Barg Kang, Seodong Shin

We investigate dark matter (DM) interpretations of the Galactic Center Excess (GCE) using 17.7 years of Fermi-LAT data and the FL16Y source catalog. We test 80 Galactic diffuse-emission models and include correlated systematic uncertainties from Galactic-plane control regions. We derive combined 95\% CL annihilation limits from 30 dwarf spheroidal galaxies (dSphs), including $J$-factor uncertainties, and compare the GCE-preferred regions with these limits and AMS-02 antiproton bounds. For self-c…

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astro-ph.COastro-ph.GA

ERGO-ML and how to directly infer the multi-temperature nature of intra-cluster gas: simulation-based inference with TNG-Cluster

Joey Braspenning, Annalisa Pillepich, Marine Prunier, Dimitris Chatzigiannakis, Dylan Nelson

Though galaxy clusters are virialized and mostly in thermodynamic equilibrium, their internal gas thermodynamics are complex. The hot gas is multiphase and spatially inhomogeneous. The exact state of the gas contains important information about the internal physics governing clusters, however, measuring the multiphase distribution of the X-ray emitting gas is hard if not impossible with current observational methods. In this work (part of the ERGO-ML series), we present a direct inference method…

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