UchUchU

Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SR

Near-Infrared Observations of BD+44 493 with IGRINS-2

Vinicius M. Placco, William D. Vacca

We present high-resolution (R~45,000), high signal-to-noise (S/N>200) H and K-band spectra of BD+44 493, obtained with the newly commissioned IGRINS-2 instrument on the Gemini North Telescope. BD+44 493 is a well-known carbon-enhanced (CEMP; [C/Fe]=+1.40) ultra metal-poor (UMP; [Fe/H]~-4.0) star that has been extensively studied with high-resolution spectroscopy from the ultraviolet to the infrared. From the IGRINS-2 data, we derive new estimates of the abundances of C, Mg, Si, and Ca by measuri…

Read →
astro-ph.EP

Probing Planet Formation with JWST Spectroscopy of IC348: Sustained Diversity but Limited Chemical Evolution and Pebble Drift

John S. Carr, Joan R. Najita

Inner disk chemistry offers a valuable window onto disk evolution and planet formation. Key planet formation processes, including pebble drift, planetesimal and planet formation, dust traps, and snow lines, determine the delivery rates of oxygen and carbon to the inner disk. As a result, measurements of molecules sensitive to the gas-phase C/O ratio, in disks over a range of ages, can constrain the relative importance and time evolution of these processes. Here we report JWST/MIRI observations o…

Read →
astro-ph.GAastro-ph.HE

Dynamics in Nuclear Stellar Clusters: The Impact of Collisions and Disrupted Binaries

Barak Rom, Re'em Sari

The nuclear stellar clusters surrounding supermassive black holes (SMBHs) host millions of stars and stellar remnants. We study how stellar collisions and binary disruptions, alongside two-body scattering and gravitational-wave (GW) emission, shape the stellar distribution and regulate the abundance of stars on tightly bound orbits. We show the following. (a) Stars in the inner region of the cluster follow a steady-state density profile scaling as $n(r)\propto r^{-5/4}$, set by the balance betwe…

Read →
astro-ph.GAastro-ph.CO

Evaluating the flexibility of the MillenniumTNG galaxy formation model with multi-zoom re-simulations

Francisco Maion, Raul E. Angulo, Volker Springel, Shy Genel, Greg L. Bryan

In this study we introduce a new simulation campaign designed to understand how parameters that control star-formation and AGN feedback processes in cosmological hydrodynamical simulations impact observables such as the galaxy stellar-mass function (GSMF) and the gas fractions in large dark matter halos. These simulations are zoom-ins to halos selected from the MillenniumTNG (MTNG) simulation, and are run employing a novel multi-zoom approach which simultaneously re-simulates several sub-regions…

Read →
astro-ph.HEastro-ph.CO

Semi-supervised morphological classification of fast radio bursts from the second CHIME/FRB catalogue

Bo Lin Fan, Renée Hložek, Antonio Herrera Martin

Understanding the morphology of fast radio bursts (FRB), and whether all sources repeat, are key challenges that are becoming more tractable given the increase in data from surveys such as the Canadian Hydrogen Intensity Mapping Experiment FRB project (CHIME/FRB). We present a Convolutional Autoencoder unsupervised classifier for separating the CHIME/FRB data into morphological classes. This data-driven approach is more reproducible than visual inspection, since groupings are learned from the da…

Read →
hep-phastro-ph.HEhep-ex

The soft volume of ultra-high energy neutrinos experiments

Stefano Palmisano, Diego Redigolo, Michele Tammaro, Andrea Tesi

We develop a semi-analytical framework to map ultra-high-energy neutrino fluxes onto event rates at neutrino telescopes. The formulation is based on the Boltzmann equation for the distribution of secondary muons produced by neutrino interactions in matter, and naturally accounts for the effective target volume relevant for through-going tracks. This "soft volume" is controlled by muon propagation and stochastic energy losses, and can be significantly larger than the instrumented detector volume.…

Read →
astro-ph.HE

Fe K$α$ line from the Broad Line Region of PDS456 with XRISM/Resolve

Alfredo Luminari, Fabrizio Nicastro, Stefano Bianchi, Elias Kammoun

The high-luminosity, high-mass and likely super-Eddington quasar PDS 456 is known for its extremely dynamic environment. A wealth of observational features from the millimetric up to the X-ray band shows energetic outflows at all scales, from accretion disc up to galaxy scales. Broad Emission Lines in the optical and UV show significant widths and line-of-sight velocities. Moreover, NIR interferometry revealed a partially outflowing Broad Line Region. Thanks to the unprecedented energy resolutio…

Read →
astro-ph.EP

Photometric Variability and Rotation of Beta Pictoris b from JWST NIRCam Coronagraphic Imaging

Yifan Zhou, Beth A. Biller, Aarynn L. Carter, Marshall D. Perrin, Michael Poon, Genaro Suárez, Ben J. Sutlieff, Johanna M. Vos et al.

We report the detection of photometric variability in the directly imaged super-Jupiter $β$ Pictoris b. Using JWST NIRCam dual-band coronagraphic imaging, we conducted a 16-hour continuous photometric monitoring campaign in the F210M and F410M filters. We developed and validated a time-series photometry framework that combines PSF subtraction, principal component analysis for systematic noise removal, and injection-and-recovery tests to confirm signal fidelity. Both light curves show consistent…

Read →
astro-ph.COastro-ph.GA

Here, There and Everywhere: How AGN jets affect galaxy cluster environments

Isaac Rosenberg, Martine Lokken, Renée Hložek, Weiguang Cui, Sara Santoni, Romeel Davé

Active galactic nuclei (AGN) feedback via black hole-driven jets and winds plays a key role in redistributing matter across megaparsec scales. However, the implementation of jet feedback in cosmological simulations remains highly prescriptive, leading to uncertainties in the predicted state of the Warm-Hot Intergalactic Medium and other extragalactic observables. We investigate how variations in AGN jet velocity, orientation, and delayed hydrodynamic coupling impact the thermodynamic state of ga…

Read →
astro-ph.HE

Synchrotron Emission from Cooled Particle Distributions

Ross Ferguson, Ben Margalit

Synchrotron emitting electrons can lose energy (`cool') through various processes including radiative losses (e.g., synchrotron or inverse-Compton cooling) and adiabatic expansion. Such cooling will shift electrons in energy-space and therefore change the electron distribution function. This in turn alters the nature of synchrotron emission and absorption from these electrons. In past literature these effects have typically been considered using either simplified one-zone frameworks, or using nu…

Read →
astro-ph.EP

On the Detectability of Volcanic Exo-Ios That May Fuel Auroras on Super-Jupiters

Brooke Kotten, Mary Anne Limbach, Johanna M. Vos, Merle Schrader, Allison McCarthy, Melodie M. Kao, Mikayla J. Wilson, Andrew Householder et al.

Studies suggest Jupiter's aurorae are supplied with plasma from volcanic outflows on the planet's innermost moon, Io. Repeating bursts of radio emission thought to trace massively scaled-up analogs of Jupiter's aurorae have been detected around nearly a dozen isolated substellar worlds, yet the source of the electrons fueling the aurorae remains unknown. Volcanism from tidally heated exosatellites may provide the plasma that fuel the aurora on these worlds. We assess whether transit observations…

Read →
astro-ph.SR

Simulating the convection in red super-giant stars: wobbling jets in common envelope evolution

Shlomi Hillel, Ron Schreier, Noam Soker

We use our newly constructed three-dimensional red supergiant (RSG) stellar model, which also mimics nuclear energy production and photospheric emission, to calculate the stochastic component of the angular momentum of the mass that a companion spiraling within the RSG's envelope accretes during common envelope evolution (CEE). The accreted mass has a fixed-direction angular-momentum component arising from the density gradient in the RSG envelope and orbital motion. The angular momentum componen…

Read →
astro-ph.SRastro-ph.GA

The Carbon-Dependent Binary Frequency of CEMP-no Stars

John D. Dixon, Terese T. Hansen, Jennifer Marshall, Vinicius M. Placco, Timothy C. Beers, Anke Ardern-Arentsen, Birgitta Nordström, Lauren N. Aldoroty et al.

Studies of the oldest and most metal-poor stars in the Milky Way have confirmed a common abundance signature of high carbon enrichment, coupled with a subsolar abundance pattern of neutron-capture elements. The so-called CEMP-no stars have been speculated to be bona fide population II stars, potentially tracing the nucleosynthesis of the very first stars formed in the universe. However, constraining the binary nature of CEMP-no stars is crucial for understanding their abundance patterns. In prev…

Read →
astro-ph.HE

Gamma-ray Modes in a Transitional Pulsar

Maksat Satybaldiev, Manuel Linares

Transitional millisecond pulsars (tMSPs) exhibit a unique sub-luminous disk state, at the cross-roads between accretion and rotation power, where they switch between two distinct X-ray modes. We present the discovery of gamma-ray modes in PSR J1023+0038, the first confirmed tMSP, from stacking Fermi-LAT data during the modes (which we identify using simultaneous X-ray observations). Surprisingly, we find that gamma-rays and X-rays are anti-correlated during this mode switching: the gamma-ray flu…

Read →
gr-qcastro-ph.HEhep-phhep-th

Antikick Relation in High-Energy Head-On Collisions of Spinning Black Holes

Carlos O. Lousto, James Healy, Alessandro Ciarfella, Hiroyuki Nakano

The collision of black holes at relativistic speeds probes gravity in its most extreme dynamical regime. While the maximum gravitational recoil from \emph{grazing} high-energy collisions ($\approx28\,562$~km/s, i.e., $\sim0.1c$) and the maximum radiated energy $E_{\rm rad}$ and remnant spin $α_f^{\max}$ from such encounters ($E_{\rm rad}/M_{\rm ADM}\approx32\%$ where $M_{\rm ADM}$ is the ADM mass, and $α_f^{\max}\approx0.987$) have been established previously~\cite{Healy:2022jbh,Healy:2024lhl},…

Read →
astro-ph.GAastro-ph.CO

Alignment of the Milky Way and M31 with their cosmic environment. New insights from constrained Local Group simulations

Hanneke C. Woudenberg, Amina Helmi, Ewoud Wempe, Anna Genina, Simon D. M. White, Jens Jasche, Guilhem Lavaux

The large-scale environment is thought to play an important role in setting galaxy properties. The Milky Way (MW) and Andromeda (M31) reside in the Local Group, embedded in the Local Sheet (LS). To study the sheet's influence on the dark matter (DM) halo shapes, spins, and disks orientations of MW and M31 analogues, we use a new suite of constrained Local Group simulations that reproduce the observed configuration of the two main halos and the LS. We determine their shapes and alignments relativ…

Read →
astro-ph.IMphysics.ins-det

picoMUX: microcontroller based time-domain multiplexing readout for kilopixel TES arrays

Simon Tartakovsky, Alexandre E. Adler, Jason E. Austermann, Steven J. Benton, Shannon M. Duff, Malcolm Durkin, Jeffrey P. Filippini, Aurelien A. Fraisse et al.

Advances in cryogenic SQUID-based time-domain multiplexing (TDM) have outpaced their warm readout electronics. Next generation CMB telescopes are baselining kilopixel TES arrays with few viable electronic options. We present picoMUX, a new TDM readout electronics architecture that replaces the FPGA typically used in such systems with a complement of modern microcontrollers. Designed around the current generation NIST multiplexer, it fully exploits its differential nature and two-level switching.…

Read →
astro-ph.EP

When Stabilizing Feedbacks Wreak Havoc in Habitable Planets: Chaos at the Freezing Point in a Four-Feedback Climate Model

Chaucer Langbert, Dániel Apai, Renu Malhotra

The long-term habitability of Earth-like planets is governed by the balance of positive and negative climate feedbacks that regulate surface temperature and atmospheric composition. While some feedbacks, such as ice-albedo and silicate weathering, are thought to operate on many terrestrial planets, the number and strength of additional climate feedbacks may vary substantially from world to world. An important open question is whether and how the introduction of an additional climate feedback inf…

Read →
astro-ph.HEgr-qc

A new model for the continuum spectra of AM CVn binaries and multi-messenger inference with normalizing flows

Nathan Steinle, Samar Safi-Harb, Austin MacMaster, Liliana Rivera Sandoval, Katelyn Breivik, Tyrone E. Woods, Tom Maccarone, Tom Wagg et al.

Future electromagnetic telescopes, such as $\textit{NewAthena}$, $\textit{CASTOR}$, and an $\textit{AXIS}$-like mission, along with milli-Hz gravitational-wave (GW) detectors such as $\textit{LISA}$, are expected to unearth the population of Galactic ultra-compact binaries (UCBs). Joint multi-messenger detections will probe the uncertain formation, evolution, and observables of mass-transferring UCBs such as AM CVns, but theoretical tools need to be advanced to anticipate future data challenges.…

Read →
astro-ph.HE

High-Resolution Numerical Calculations of GRB Afterglow Plateaus arising from Stratified Ejecta

Paul C. Duffell, Ranadeep Ghosh Dastidar

Since the discovery of plateaus in GRB afterglows by Swift, they have been modeled predominantly by late-time energy injection. However, many studies have suggested that the plateau may be modeled by an early phase before reverse shock crossing (either coasting with constant Lorentz factor or decelerating very slowly as the reverse shock crosses the ejecta). The slope of the early plateau provides some constraints the stratification of the fastest-moving ejecta, which could be the ejecta respons…

Read →
astro-ph.GA

Dynamical modelling of giant radio quasars in the HETDEX Spring Field

T. M. O. Franzen, J. Machalski, M. Jamrozy, R. Morganti, D. A. Green, Y. C. Perrott, T. W. Shimwell

Giant radio sources are defined as extragalactic radio sources, hosted by galaxies or quasars, with linear sizes $\geq 0.7$ Mpc. They are thought to represent the final stage of the evolution of radio galaxies whose sizes range from pc to Mpc scales. We analyse in detail the radio morphology and spectra between 54 MHz and 4.85/15.5 GHz of 15 giant radio quasars (GRQs) in the HETDEX Spring Field, and fit dynamical evolution models to the sources' observational properties to study their physical p…

Read →
astro-ph.IM

Fast and accurate bandpass integration of complex SEDs with neural networks

L. A. Bianchi

The paper presents a novel ML-based approach for fast and accurate bandpass integration of spectral energy distributions (SEDs). The non-locality of the integral operator involved guarantees the smoothness of the target function to be approximated, making it an excellent use-case for neural networks. The computational method developed for this work has been wrapped within pyfine (FINE: Fast Function Interpolation via NEural NEtworks). This new Python package makes the relevant code available and…

Read →
astro-ph.GA

SMA Observations of the Archetypal Compact Steep-spectrum Radio Source 3C 303.1

Rushikesh Bhutkar, Mark Gurwell, Christopher O'Dea, Mojegan Azadi, Belinda Wilkes, Stefi Baum, D. J. Saikia, Grant Tremblay et al.

AGN (active galactic nuclei) feedback plays a crucial role in shaping galaxy evolution. Numerical simulations show that the kinetic energy transfer efficiency from radio jets to interstellar medium (ISM) is relatively high, suggesting a significant role of radio jets in the feedback. We investigate AGN feedback on cold gas in the compact steep-spectrum (CSS) radio source 3C 303.1. CSS sources are largely young radio galaxies evolving through dense environments of their host galaxies. This early…

Read →
astro-ph.SR

Structure and Dynamics of the Inner Corona Measured from the DEB Initiative 2024 Eclipse Image Sequence

Matthew J Penn, Robert Baer, Chris Mandrell, Corinne Brevik, Castor Fu, Mike Conley, Richard Danley, Harvey Henson et al.

The Dynamic Eclipse Broadcast (DEB) Initiative citizen science program observed coronal visible continuum brightness during the 2024 April 8 total eclipse from locations across North America. We present results from 11 DEB sites spanning 2700 km of distance and showing 49 minutes of evolution. The coronal brightness radial profiles from these telescopes are tightly correlated from 1.2 to 4.0 solar radii and comparable to published photometric coronal intensities. The coronal flattening parameter…

Read →
astro-ph.GA

The MAGPI survey: Stellar populations radial trends and mass assembly in star-forming galaxies at z~0.3

Federica Mauro, Bodo Ziegler, Iris Breda, Polychronis Papaderos, Gauri Sharma, Sabine Thater, Katherine E. Harborne, Trevor Mendel et al.

The evolution of galaxies from cosmic noon to the present day provides a key window to probe the balance between early, rapid bulge formation and prolonged disk growth. The epoch at $z \sim 0.3$ marks a crucial transitional phase between the peak of cosmic star formation and the predominantly quiescent local Universe. In this work, we examine the spatially resolved stellar populations of 34 galaxies at $z \sim 0.3$ to quantify radial gradients in age, stellar metallicity, and star formation acti…

Read →
astro-ph.IM

Updates to the WFC3/IR Photometric Stability Stellar Cluster Study

Ky Huynh, Varun Bajaj

The WFC3/IR channel has been shown to lose sensitivity over time. The sensitivity loss rate has been quantified in past works and we extend those measurements into 2026 using photometry of uncrowded regions of star clusters 47 Tucanae and Messier 4 in the F110W and F160W filters. This study adds 4-7 additional visits since Bajaj et al. (2022) for each target/filter combination. Using F160W data of 47Tuc, we find that the IR channel continues to lose sensitivity at a rate of -0.07% $\pm$ 0.01% pe…

Read →
astro-ph.HE

Investigating the Periodic X-ray Behaviour in the Eclipsing AGN NGC 6814

T. O. Hodd, L. C. Gallo, A. G. Gonzalez, J. M. Miller, D. Rogantini

A 2016 XMM-Newton X-ray light curve of the Seyfert 1.5 galaxy NGC 6814 exhibited clear eclipsing behaviour, with distinct ingress and egress, during half of the observation. Here, we report on the periodic behaviour in the light curve prior to the eclipse. We use timing and spectral analysis techniques to quantify the behaviour and examine the characteristics of the periodic signal. A superlet transform of the X-ray light curve reveals a period of ~45-50 $μ$Hz in the initial 60 ks of the observa…

Read →
astro-ph.IM

Establishing baseline model performances for optical turbulence forecasting

M. De Sepibus, E. Masciadri, C. Weinberger, C. Veillet, S. Ragland

Accurate optical turbulence (OT) forecasts help telescopes observe with maximum efficiency, as the performance of adaptive optics (AO) systems strongly depends on turbulence conditions. OT forecasting remains a challenging problem. A wide range of methods has been explored to address this problem, including numerical weather prediction (NWP) models, machine learning algorithms, and hybrid approaches, each varying in complexity, computational cost, and accuracy. Assessing the performance of forec…

Read →
astro-ph.IMastro-ph.EP

Astra: an open-source fully autonomous robotic observatory control software

Peter P. Pedersen, David Degen, Lionel Garcia, Urs Schroffenegger, Daniel Sebastian, Sebastián Zúñiga-Fernández, Brice-Olivier Demory, Elsa Ducrot et al.

Robotic and autonomous observatories are critical for modern time-domain and high-cadence astronomical surveys. The operation of these facilities requires complex software coordination to manage hardware, schedule observations, and ensure safety. However, existing observatory control software are often proprietary and platform-locked or require complex message-brokering infrastructure. Here we present Astra (Automated Survey observaTory Robotised with Alpaca): an open-source, cross-platform Pyth…

Read →
astro-ph.HE

Momentum Space Resolution Dependence in Boltzmann Neutrino Radiation Hydrodynamics Simulations of Core-collapse Supernovae

Ryuichiro Akaho

Finite momentum space resolution is a primary source of uncertainty in solving the Boltzmann equation with the discrete-ordinates method. In this paper, the momentum space resolution dependence of Boltzmann neutrino transport is studied by performing a series of two-dimensional core-collapse supernova (CCSN) simulations. The effects on the explosion dynamics are discussed by individually varying the resolutions of the zenith and azimuth angles in momentum space, and of the energy. It is found th…

Read →