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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Estimating Cluster Galaxy Infall Time from Phase Space in TNG

Cameron Lawlor-Forsyth

Using the TNG300 and TNG-Cluster simulations, phase space-based estimates for galaxy infall time onto clusters with $M_{\mathrm{h}} \geqslant 10^{14}~M_{\odot}$ are determined for all simulation snapshots with $z \leqslant 1$. These infall time estimates are consistent with previous work in the literature, and can be readily applied to observations of cluster galaxies, where no other estimate is feasible, based only on the galaxy's position in projected phase space. The analysis pipeline used to…

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astro-ph.GAastro-ph.IM

Spectral Data-cube Cleaning for CCAT Deep Spectroscopic Survey. I. Effect of correlated noise and filtering on the power spectrum

A. Dev, C. Karoumpis, Y. Okada, K. Basu, F. Bertoldi, D. Chung, J. Clarke, R. Freundt et al.

The Epoch of Reionization Spectrometer (EoR-Spec) on the Fred Young Submillimeter Telescope (FYST) will conduct the CCAT Deep Spectroscopic Survey (DSS) to perform line-intensity mapping of redshifted [C II] emission. Atmospheric $1/f$ noise and instrumental systematics affect power-spectrum recovery. We present realistic end-to-end simulations to quantify these effects and evaluate a Filter-and-Bin (F&B) pipeline. The simulated observations include instrument response, astrophysical emission, a…

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astro-ph.HE

Pulsar glitches in the presence of vortex traps

Anantharaman Sekharipuram Viswanathan, Dipankar Bhattacharya, M. Ali Alpar, Erbil Gügercinoğlu

Pulsar glitches are thought to originate when angular momentum is transferred to the crust of the neutron star from the superfluid enclosed within, mediated by vortex avalanches. This idea has been qualitatively validated in the existing literature by simulating a star with a small number ($\sim 10^{3}$) of superfluid vortices, subject to deceleration and uniform pinning. Here, we employ the Barnes-Hut approximation to simulate up to $10^{5}$ vortices in a reasonable time. Using the new setup, w…

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astro-ph.GAastro-ph.HE

Gas accretion onto the Milky Way: high-velocity cloud survival and the revival of the terminal-velocity paradigm

Michael M. Schulreich, Dieter Breitschwerdt, Jürgen Kerp

The terminal-velocity paradigm has long been used to interpret the motion and infer the distances of HVCs accreting onto the Milky Way, yet its validity under realistic Galactic conditions remains uncertain. We investigate its dynamical limits by combining analytical modelling with three-dimensional hydrodynamical simulations of clouds moving through a stratified Milky Way halo. We derive a generalized equation of motion including gravity, ram-pressure drag, a phenomenological mass-exchange mode…

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physics.ins-detastro-ph.IM

Overview and design optimization of a custom hybrid X-ray telescope for the International Axion Observatory (IAXO)

Yue Yu, Jooyun Woo, Ipek Altunyurt, Stefano Basso, Vadim Burwitz, Francisco R. Candón, Juan Francisco Castel Pablo, Marta M. Civitani et al.

We present the design optimization for maximizing the effective area of a custom X-ray optic for the International Axion Observatory (IAXO) and BabyIAXO, including its novel hybrid configuration that enables full coverage of the 700-mm-diameter magnetic bore with minimal stress imposed on the mirrors; shell layout optimized for axion spectra and spatial distribution; and the coating recipes that enhance reflectivity in the energy range of interest. We evaluate how these design choices improve th…

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astro-ph.IM

The High-Speed FPGA Readout System for the Advanced X-ray Imaging Satellite (AXIS)

Declan O'Neill, Jill Juneau, Peter Orel, Sven Herrmann, Gregory Prigozhin, Eric D. Miller, Steven W. Allen, Marshall W. Bautz et al.

The Advanced X-ray Imaging Satellite (AXIS) is a Probe-class mission concept designed to deliver arcsecond spatial resolution, high-sensitivity spectral imaging across the 0.3-10 keV band. The X-ray Astronomy and Observational Cosmology (XOC) Group at Stanford, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing the AXIS X-ray camera, including both the detector and the front-end readout electronics required to meet the mission's demanding perfo…

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astro-ph.HE

Probing the High-Energy Emission of the VHE-emitting Changing-Look Blazar B2 1420+32

Anjum Peer, Zahir Shah, Sikandar Akbar, Bari Maqbool, Ranjeev Misra

We present a multi-wavelength temporal and spectral study of the changing-look blazar B2~1420+32 using \emph{Fermi}-LAT, \emph{Swift}-XRT, and \emph{Swift}-UVOT data from MJD~58818--60721. The source reached a peak 0.1--300~GeV photon flux of $(4.62 \pm 0.29) \times 10^{-6}\,\mathrm{ph\,cm^{-2}\,s^{-1}}$ around MJD~60488, about 60 times the 4FGL-DR4 average, during which the photon index hardened to $2.19 \pm 0.14$; the flux--index evolution shows only weak evidence for global harder-when-bright…

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astro-ph.COastro-ph.GA

The burgeoning rise of the 21-cm forest I: constraints on the optical depth of the intergalactic medium at $5.38 < z < 5.84$

Chanasorn Kongprachaya, Gianni Bernardi, Emilio Ceccotti, Andrei Mesinger, Benedetta Ciardi, Oleg M. Smirnov

The redshifted 21-cm line is a promising probe of the Epoch of Reionization, during which the first generation of stars ionized the InterGalactic Medium (IGM). We aimed to constrain the IGM neutral Hydrogen fraction and spin temperature via redshifted 21-cm absorption against high-redshift radio sources. We analysed an 18-hour observation of the radio-loud quasar PSO J352.4034-15.3373 ($z = 5.84$) in the 203-222.5 MHz band. We obtained a continuum image with a $0.66$ mJy/beam rms noise and a spe…

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astro-ph.IM

Fast, low-noise CCD systems for future strategic X-ray missions

Haley R. Stueber, Tanmoy Chattopadhyay, Tonya L. Peshel, Abigail Y. Pan, Steven W. Allen, Marshall W. Bautz, Kevan Donlon, Catherine E. Grant et al.

Future strategic X-ray missions, such as those targeted by the Great Observatories Maturation Program (GOMaP), require fast, low-noise X-ray imaging spectrometers. To achieve the speed and noise capabilities required by such programs, our Stanford team, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing enhanced X-ray charge-coupled devices (CCDs) and readout systems that leverage tailored application-specific integrated circuits (ASICs). Here,…

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astro-ph.IM

HARMONI at ELT: Reoptimization of the NGSS natural guide star sensors system for MCAO compatibility

Kjetil Dohlen, David Le Mignant, Anne Bonnefoi, Marc Dubbeldam, Johan Floriot, Iago Funes Vecino, Laurent Jocou, Yoann Richaud et al.

HARMONI is the first-light, adaptive optics assisted, near-IR integral field spectrograph for the ELT. It covers a spectral range from below 800nm to 2400nm with resolving powers from 3000 to 7000 and spatial sampling of 25mas and 6mas. It can operate in three adaptive optics (AO) modes: single conjugate AO (SCAO), high-contrast AO (HCAO), and multi-conjugate AO (MCAO). The project is resuming its final design phase after a rescope design phase that has lasted two years. This paper describes the…

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astro-ph.HE

Long-lived intermittent accretion disks in the jittering jets explosion mechanism (JJEM) of core-collapse supernovae

Noam Soker

Motivated by observations of core-collapse supernova (CCSN) remnants that suggest cases where one to three energetic pairs of jets dominate the CCSN remnant morphology and, hence, the CCSN explosion energy, I examine the formation of long-lived intermittent accretion disks that launch such pairs of energetic jets in the framework of the jittering-jets explosion mechanism (JJEM). In the JJEM, pairs of jets explode all CCSNe. In most CCSNe, stochastic angular momentum fluctuations in the convectiv…

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physics.ins-detastro-ph.HEastro-ph.IMhep-exhep-ph

Fabrication status and expected performance of the inner-core X-ray optic for BabyIAXO

Jooyun Woo, Yue Yu, Ipek Altunyurt, Todd Decker, Desiree Della Monica Ferreira, Peter Lindquist Henriksen, Eftychia Kotsiou, Sonny Massahi et al.

BabyIAXO, a pathfinder for the International Axion Observatory (IAXO), is designed to demonstrate all key technologies at scale while achieving an improvement in sensitivity over the recent CERN Axion Solar Telescope (CAST) experiment by approximately a factor of five. Such improvement is enabled by the X-ray optics, which allow for maintaining a high signal-to-noise ratio at the detector despite a cross-sectional area of the magnetic bore being over 250 times larger than that of CAST. The optic…

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astro-ph.EPastro-ph.SR

Planetesimal Formation Across the Stellar Mass Spectrum and its Influence on Exoplanet-Inherited Volatile Budgets

Joe Williams, Sebastiaan Krijt, Joanna Drążkowska, Tim Lichtenberg

Protoplanetary discs emerging from collapsing molecular clouds are capable of forming planetesimals at the water snowline during both the cloud collapse and Class II disc phases; such a scenario could be responsible for creating the carbonaceous/non-carbonaceous (CC/NC) heterogeneity observed in the Solar System, and bears important implications for emergent planetary compositions. We use 1D simulations of a viscously evolving disc coupled with cloud collapse and planetesimal formation to explor…

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astro-ph.GA

Testing dark matter density profiles based on Padé approximants of different orders

Talgar Konysbayev, Orlando Luongo, Marco Muccino, Yergali Kurmanov, Kuantay Boshkayev, Gulnara Suliyeva, Ainur Urazalina, Guldana Rabigulova et al.

We investigate whether low-order Padé rational functions can be used as empirical density profiles for modeling dark matter halos from galaxy RCs. We introduce three parameterizations determined from Padé series, denoted Padé 02, Padé 12 and Padé 03, and compare them with pseudo-isothermal, Burkert, Beta, Brownstein, exponential-sphere and Persic models. The analysis is performed for eight galaxies under the assumption that RCs are dark matter dominated. The parameters are inferred from RC data…

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astro-ph.IMastro-ph.EPastro-ph.GA

Microlensing Detection and Inference via Learned Bayes Factors

Nolan Smyth, Laurence Perreault-Levasseur, Yashar Hezaveh

We present a unified framework for gravitational microlensing event detection and parameter inference. Traditional pipelines use deterministic hard cuts on photometric statistics, systematically missing low-magnification events in the finite-source regime. We instead frame detection as Bayesian model comparison using Evidence Networks, which learn calibrated Bayes factors from binary-labeled simulations, and combine this with Neural Posterior Estimation (NPE) for amortized parameter inference. B…

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astro-ph.IM

Long-term performance of the MLR-TT sensor: two-photon polymerization validation in the telescope environment

Robert J. Harris, Philipp Hottinger, Jonathan Crass, Philipp-Immanuel Dietrich, Christian Koos

We report on the long-term optical performance of a two-photon polmerized microlens ring tip-tilt sensor. The study is backed by repeated measurements over the last six years, since the sensor was first tested in the sky at the Large Binocular Telescope. The goal of the study is to assess the feasibility of the underlying technology of two-photon polymerization for future instrumentation in the realistic environments experienced at astronomical telescopes.

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physics.comp-phastro-ph.EPcs.LG

Dynamical and Optimization Trade-offs of Levi--Civita Coordinates for Learned Close-Encounter Dynamics

Abhishek Shankar

Classical regularization removes the binary-collision singularity from the Kepler problem, but its value as a representation for learned Hamiltonian dynamics has not been systematically isolated. We compare Cartesian and planar Levi--Civita formulations of a perturbed Kepler system with a smooth quadrupole potential. With the perturbation supplied analytically, a Levi--Civita Hamiltonian splitting holds the maximum relative energy error near $2.1\times10^{-5}$ through eccentricity $e=0.99$, whil…

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astro-ph.HEastro-ph.IM

Identifying Kilonovae in the Presence of Optical Afterglow for the Wide-Field Survey Telescope

Huan Yang, Zhengyan Liu, Liang-Duan Liu, Wen Zhao, Zigao Dai

Identifying kilonovae associated with binary neutron star mergers is often complicated by the presence of a dominant synchrotron afterglow. In this work, we evaluate the performance of the Wide-Field Survey Telescope (WFST) in identifying kilonova signals in composite afterglow-kilonova transients. Using a numerical framework based on the Fisher information matrix, we simulate $10,000$ realizations for each of two scenarios: an AT2017gfo-based template model and a physically sampled population t…

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astro-ph.HE

Shock acceleration in vortex driven magnetic fields of black holes

Zaza N. Osmanov

The aim of this work is to investigate particle acceleration by shock waves in the magnetospheres of supermassive black holes, where the magnetic field is vortex-driven. For this purpose, we investigated the first-order Fermi acceleration process at relativistic shocks in the magnetospheres of supermassive black holes. In our analysis, we considered synchrotron radiation and inverse Compton scattering as the principal energy-loss mechanisms limiting the maximum attainable particle energy. We inv…

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astro-ph.IM

Asgard/NOTT: Cryogenic characterization of the mid-infrared chip

G. Garreau, D. Defrère, R. Laugier, P. Chingaipe, M-A. Martinod, T. Mattheussen, K. Missiaen, J. Morren et al.

NOTT is part of the new visitor instrument suite Asgard for the Very Large Telescope Interferometer (VLTI), and the first long-baseline nulling interferometer that will be operational in the southern hemisphere. It is an L'-band (3.5-4$\,μ$m) instrument optimized for imaging hot exozodiacal dust and young giant planets orbiting around the snowline of nearby main-sequence stars. For planet imaging, the L' band has the advantage of relaxing the requirements on the star-planet contrast to $\sim 10^…

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astro-ph.IM

ESO-VLT BlueMUSE instrument - Conceptual Design for Phase A

Florence Laurent, Johan Richard, Rémi Giroud, Davor Krajnović, Alexandre Jeanneau, Manuel Abreu, Angela Adamo, Théo Battrel et al.

BlueMUSE is a blue-optimised, medium spectral resolution, panoramic integral field spectrograph under development for the ESO's Very Large Telescope (VLT). The project is now entering preliminary design phase. With an optimised transmission down to 350 nm, spectral resolution of R $\sim$ 3500 on average across the wavelength range, and a large FoV (1 arcmin2), BlueMUSE will open up a new range of galactic and extragalactic science cases facilitated by its specific capabilities. BlueMUSE consists…

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astro-ph.SR

Relationship of ICME Composition Signatures with Solar Activity during 2009-2025

Diyorbek Pulatov, Zavkiddin Mirtoshev, Mirabbos Mirkamalov

Coronal Mass Ejections (CMEs) are among the most energetic solar eruptions, expelling magnetized plasma from the corona into interplanetary space. Their interplanetary counterparts, known as Interplanetary Coronal Mass Ejections (ICMEs), retain distinct compositional signatures that reflect the physical conditions of their solar source regions. This study presents a statistical analysis of ICME composition dependence on solar activity during 2009--2025, covering Solar Cycle (SC) 24 and the ascen…

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astro-ph.EP

Dust and Gas Transport in Substructured Nonideal MHD Wind-Launching Disks with Embedded Planets

Chun-Yen Hsu, Zhi-Yun Li, Xiao Hu, Yisheng Tu, Min-Kai Lin

Radial dust transport in protoplanetary disks is a key process shaping planet formation and disk chemistry. We investigate how this transport, along with gas transport, is regulated in wind-launching disks with embedded planets using three-dimensional nonideal MHD simulations. We find that disk substructures do not act as absolute barriers to transport. Low-mass planets leave the disk structure dominated by the magnetic wind, while a Jupiter-mass planet opens a deep gap and drives spiral shocks.…

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astro-ph.IM

Achieving efficient broadband spatial filtering for LIFE: status and plan

G. Garreau, T. Birbacher, L. Desdoigts, L. D. Feinberg, A. M. Glauser, J. T. Hansen, M. Ireland, J. Pino et al.

Nulling interferometry is one of the most promising techniques that is envisioned for the imaging and characterization of exoplanets in the mid-infrared for ground-based and space-based observatories. On the ground, the upcoming Asgard/NOTT visitor instrument for the Very Large Telescope Interferometer (VLTI) is expected to be the first nuller to observe young giant exoplanets. The Large Interferometer For Exoplanets (LIFE) project aims at implementing long-baseline nulling interferometry in spa…

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astro-ph.EPastro-ph.IM

Predicting Atmospheric Re-entries Using Segmented M/A Calibration of Public TLE Data

Joseph Remis

We present a reproducible method for predicting atmospheric re-entries using only publicly available Two-Line Elements (TLEs). The approach is based on a segmented calibration of the effective mass-to-area ratio (M/A), adjusted independently over intervals of at least 12 hours to suppress short-period catalogue noise. Longer segments provide a stable dynamical signal from which the effective drag behaviour can be retrieved. Applied to recent natural re-entries of rocket bodies, debris, and non-m…

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astro-ph.IMphysics.ins-det

Skipper CCD readout time optimization for astronomical applications

Johannes Wüthrich, Andrin Fazan, Sean MacBride, Marcelle Soares-Santos

Skipper CCDs enable the reduction of CCD readout noise by non-destructively measuring the individual pixel charge packets multiple times. This readout noise reduction has attracted considerable interest in the astronomical community, particularly in spectroscopic surveys targeting faint objects at high redshifts. However, noise reduction via repetitive sampling leads to an unavoidable increase in readout time, often to prohibitive levels. To enable their use in astronomical applications, the opt…

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astro-ph.COastro-ph.GA

Modeling the HI-Halo Connection: Evolution, Scatter, and a Halo-based Prescription for 21-cm Mock Catalogs

Mohd Kamran, Gabriella De Lucia, Marta Spinelli, Lizhi Xie, Fabio Fontanot, Michaela Hirschmann

The redshifted 21-cm line of neutral hydrogen (HI) is a powerful tracer of large-scale structure, and post-reionization HI intensity mapping is emerging as a competitive cosmological probe whose interpretation requires a description of how HI populates galaxies and dark matter halos. We characterize the HI--halo mass relation, its redshift evolution, and its intrinsic scatter, identifying its secondary dependences. We use the updated GAlaxy Evolution and Assembly (GAEA) semi-analytic model, appl…

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astro-ph.GAastro-ph.SR

A universal chromosome map for globular clusters: chemical calibration and environmental regulation of the multiple populations

C. Lardo, M. Salaris, N. Bastian, C. Charbonnel, E. Dalessandro, E. Dondoglio, M. Gieles, M. G. H. Krause et al.

Chromosome maps (ChMs) are two-dimensional diagrams of UV/optical pseudocolours widely used to diagnose the multiple stellar populations (MPs) phenomenon in globular clusters. Their raw morphology is affected by the metallicity-dependent response of the photometric filters, preventing unbiased comparisons across clusters of different metallicities. We identify a cross-cluster ChM framework that accounts for this dependence, enabling an unbiased investigation of the physical drivers of MP diversi…

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astro-ph.GAastro-ph.CO

Galactic Science with the LiteBIRD satellite: Spectral characterization of diffuse Galactic polarized emission at the angular power spectrum level

S. Vinzl, J. Aumont, L. Vacher, R. T. Génova-Santos, D. Adak, A. Rizzieri, H. Akamatsu, E. Allys et al.

Detection of primordial $B$-mode polarization in the cosmic microwave background (CMB) from tensor perturbations generated during inflation is a major scientific goal of future CMB missions. Its success will strongly depend on the characterization of polarized foregrounds, a challenge that the LiteBIRD satellite aims to tackle with its 15 frequency bands ranging from 40 to 402 GHz. In this work, we forecast the ability of LiteBIRD to characterize polarized dust and synchrotron emission in the di…

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astro-ph.SR

Height Dependent Phase Shifts of Wave Pulses in the Lower Solar Atmosphere Measured with SUNRISE III

Andreas Lagg, H. N. Smitha, Sami K. Solanki, Tino L. Riethmüller, Achim Gandorfer, Alex Feller, Francisco A. Iglesias, Azaymi L. Siu-Tapia et al.

We report on the measurement of the height-dependent time shifts of wave pulses in the lower solar atmosphere from high-resolution spectro-polarimetric observations obtained with the SUSI instrument on board the SUNRISE III balloon-borne solar observatory during its successful science flight in July 2024. The line-of-sight velocities derived from the line-core positions of 19 spectral lines in a 2 nm-wide window around the Ca II H line were used to determine the time shifts of propagating pulses…

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