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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SR

Positive superhumps in high mass ratio cataclysmic variables driven by apsidal disk precession

Rebecca G. Martin, Stephen H. Lubow, David Vallet, Stephen Lepp

Previously it has been assumed that a cataclysmic variable (CV) disk can only become eccentric and display superhumps if the 3:1 resonance is located within the disk. This requires the binary mass ratio to be $q=M_2/M_1\lesssim 0.33$, where $M_1$ is the mass of the white dwarf and $M_2$ is the mass of the companion star. However, several systems with higher mass ratios have been observed to exhibit positive superhumps, posing a challenge to this picture. We present the first 3D hydrodynamic simu…

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astro-ph.IM

Enhancing WISE Infrared Imaging to Spitzer Resolution Using Deep Learning Super-Resolution

Saeed Rezaee, Shoubaneh Hemmati, Bahram Mobasher, Naveen A. Reddy, Tara Fetherolf, Alexander de la Vega, Sina Miri

We present a deep-learning framework that performs 4.6x spatial super-resolution from WISE W1 (3.4 micron) toward Spitzer IRAC Ch1 (3.6 micron), and characterize its behavior on the COSMOS field. Our sample consists of ~390,000 paired cutouts drawn uniformly within the WISE/Spitzer overlap, with a held-out test set of 83,592 cutouts on which we report all metrics. The framework uses a convolutional neural network (an Enhanced Residual Channel Attention Network) trained with a loss function that…

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astro-ph.SRastro-ph.EP

Preferential alignment of Class 0, Class I protostellar disks in multiple systems across nine nearby molecular clouds

Cheng-Han Hsieh, Aleksey Generozov, Stella S. R. Offner, Héctor G. Arce, Jaime E. Pineda, Michael M. Dunham, Diego Mardones, Dominique Segura-Cox et al.

Protostellar disk orientations in multiple systems provide critical insights into the primary mechanisms that govern the formation of multiple-star systems, their subsequent dynamical evolution, and their impact on planet-forming disks. We present a disk alignment study of 512 Class 0, Class I, and flat-spectrum protostars across nine nearby molecular clouds within 500 pc, utilizing data from the CAMPOS and VANDAM surveys. Our sample includes 74 binaries and 31 high-order multiple systems. We fi…

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astro-ph.IM

Expanding the SPISEA Stellar Population Synthesis Software to the Substellar Regime

Caitlin Begbie, Rachel Street, Katarzyna Kruszynska, Jessica Lu, Matthew Hosek, Natasha Abrams, Macy Huston

We present an extension of the SPISEA stellar population synthesis framework that adds brown dwarfs to the existing range of stellar mass objects, enabling physically consistent modeling of brown dwarfs within synthetic star clusters. Previous versions of SPISEA included limited substellar support, relying on outdated initial mass functions and incomplete atmospheric and evolutionary coverage below the hydrogen-burning limit. This was addressed through the implementation of a modern substellar i…

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astro-ph.COastro-ph.HE

Cosmological $γ$-$γ$ Pair-Production Background

Mika A. Gelowicz, Thomas Siegert, Saurabh Mittal, Laura Eisenberger, Dimitris Tsatsis, Niklas C. Bauer, Rudi Reinhardt, Patrik Ehrmann et al.

The origin of positrons is one of the unsolved puzzles in astrophysics as the majority of sources are still unidentified. The Cosmic Photon Background (CPB) is the isotropic radiation spanning the entire electromagnetic spectrum. Interactions of the CPB with itself may pose a promising source of positrons and secondary emission. We calculate the electron-positron pair production rate from the $γ$-$γ$ pair-production of the CPB with itself for redshifts $z \leq 10$, and determine the annihilation…

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astro-ph.IM

DragonflyPol: Wide-Field Optical Linear Polarimetry with the Dragonfly Telephoto Array (Instrument Description and Commissioning)

Mehrnoosh Tahani, Leo Hollberg, Hiroshi Akitaya, Jaeyeon Kim, Deborah Lokhorst, Roberto Abraham, Pieter van Dokkum, William P. Bowman et al.

We present DragonflyPol, a wide-field optical linear polarimetry capability implemented on the Dragonfly Telephoto Array. DragonflyPol leverages Dragonfly's modular, multi-lens architecture to obtain simultaneous measurements in four linear polarization orientations ($0^\circ$, $45^\circ$, $90^\circ$, and $135^\circ$) across a $\sim5\,deg^2$ field of view, distributed across 44 polarized lens--detector units. Four additional units serve as unpolarized reference channels. We describe a broad rang…

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hep-phastro-ph.HE

Constraining the Coexistence of Primordial Black Holes and Particle Dark Matter with Neutrino Observations

Prolay Chanda, Sagnik Mukherjee, James Unwin

Primordial black holes (PBH) with a uniform mass scale could contribute up to 1\% of the gravitationally inferred dark matter relic abundance and remain consistent with observational limits over a large range of masses. In this case, the vast majority of the dark matter relic abundance is comprised of dark matter particles, such as WIMPs or FIMPs. Particle dark matter gravitationally captured around primordial black holes can form dense minispikes in which the annihilation rate is strongly enhan…

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astro-ph.EPastro-ph.SR

First planetesimals from DESI DR1: 12 highly metal-rich white dwarfs

Paula Izquierdo, Andrew Swan, Boris T. Gänsicke, Jamie T. Williams, Detlev Koester, Nicola P. Gentile-Fusillo, Christopher J. Manser, Laura K. Rogers et al.

Metal-enriched white dwarfs provide a unique insight into the composition of exoplanet interiors. These stars accrete the debris of disrupted planetary bodies, and hence, measuring the stellar parameters and photospheric abundances yields the bulk compositions of the parent bodies. At present, over 1750 debris-accreting white dwarfs are known, but just a few dozen are sufficiently enriched to allow a detailed abundance study. Here we report the analysis of 12 highly metal-enriched white dwarfs o…

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astro-ph.IM

COS2035: Extending COS/FUV Operations Through the 2030s

Marc Rafelski, David Sahnow, Christian I. Johnson, Bethan James, Svea Hernandez, John Debes, Beverly Serrano, Kate Davis et al.

The far-ultraviolet (FUV) detector of the Cosmic Origins Spectrograph (COS) accumulates gain sag where photons land, and without continued mitigation this degradation would render the most used modes unusable. To extend COS FUV operations through the 2030s, the COS team developed the COS2035 strategy, which builds on the existing COS2025 rules with four technical breakthroughs and two new usage policies. First, SPLIT-wavecals decouple wavelength calibration from science exposures and open detect…

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astro-ph.GA

Efficient Interstellar Grain Growth from High Sticking Coefficients on Amorphous Carbon Dust

Clarke J. Esmerian, Duncan Bossion, Francois Dulieu, Saoud Baouche, Alexey Potapov, W. M. C. Sameera, Tom J. L. C. Bakx, Susanne Aalto et al.

Cosmic dust is the solid phase of the interstellar medium (ISM), classically assumed to be composed of carbonaceous and silicate grains with size distributions spanning $\sim 5~Å$ to $\sim 1~μ$m (Weingartner & Draine 2001, Draine & Li 2007, Hensley & Draine 2023). While it constitutes at most order-of-magnitude $\mathbf{1\%}$ of the ISM mass, dust is second only to stars in importance for the observable properties of galaxies (Zavala et al. 2021). Large uncertainties in the efficiency of grain g…

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astro-ph.HEphysics.plasm-ph

Ultra-long simulations of collisionless relativistic shocks in front-comoving frame: evidence for a steady state and its properties

Mikhail Garasev, Evgeny Derishev

We present a series of unprecedently long 2D3V PIC simulations of unmagnetized relativistic $e^{-}e^{+}$-pair shocks performed in a front-comoving frame. By implementing a moving-wall boundary condition in the downstream together with continuous injection at the upstream boundary, we maintain a fixed simulation domain size, opening the way to perform substantially longer simulations. Our longest runs extend beyond $100000\,ω_p^{-1}$, exceeding the duration of the previously published simulations…

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astro-ph.EPastro-ph.HEastro-ph.SR

Hierarchical Three-Body Problem at High Eccentricities = Simple Pendulum, IV: Octupole for Librating Kozai-Lidov Cycles

Ygal Y. Klein

We solve analytically the long-term octupole evolution of \textit{librating} Kozai-Lidov cycles - those with a negative Kozai constant, in which the argument of pericenter librates - in the double-averaged restricted hierarchical three-body problem. Librating cycles reach extreme eccentricities when the normal component of the orbital angular momentum vanishes, just as rotating cycles do, but their slow dynamics was left unsolved: as noted by Katz, Dong \& Malhotra (2011), the azimuth of the ecc…

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astro-ph.EP

The Expected Yield of Venus Zone Terrestrial Planets from PLATO

Stephen R. Kane, Emma L. Miles, Colby M. Ostberg, Erika Kohler, James B. Garvin

The characterization of terrestrial exoplanets and the conditions that lead to divergent climate outcomes is a primary goal of exoplanetary science. The Venus Zone (VZ) provides a framework for identifying planets that may have experienced runaway greenhouse processes similar to Venus, and the statistical properties of such planets bear directly on models of planetary habitability. Here we present a quantitative estimate of the expected yield of VZ terrestrial planets from ESA's PLATO (PLAnetary…

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astro-ph.GA

Chemodynamical evidence of the HR 1614 moving group as a bar resonance

Andreas J. Koch-Hansen, Vladislav Gulaev, Dominik H. Plonka, Camilla Juul Hansen, Andrew McWilliam, Victor P. Debattista, Zdenek Prudil

Moving groups (MGs) are ensembles of disk stars that clump in velocity and action space. A multitude of explanations as to their origin has been attempted, from dissolved star clusters to resonances with the Galactic bar, or other non-axisymmetric perturbations. The object of this work, the old HR 1614 group, has in the past already been shown to not be a disrupted cluster in terms of its broad age and metallicity distribution. Thus its stars have more likely been trapped by the Milky Way bar at…

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astro-ph.HE

Signatures of Black Hole Spin in Horizon-Scale Polarimetry

George N. Wong, Daniel C. M. Palumbo, Zachary Gelles, Andrew Chael

The angular momentum of a black hole, usually expressed in terms of a dimensionless "spin," both shapes the strong-field spacetime and provides a reservoir of rotational energy that can be exchanged with surrounding plasma. Very long baseline interferometry (VLBI) has now begun to resolve polarized emission on event-horizon scales. We distinguish polarimetric signatures of spin arising primarily from photon propagation in the Kerr spacetime from those mediated by horizon-threading electromagneti…

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

The topology of the magnetic field in Abell 2255 out to its virial radius. Results from the LOFAR Galaxy Cluster Ultra-Deep Field

A. Botteon, R. J. van Weeren, Y. Hu, F. Vazza, G. Brunetti, K. Rajpurohit, A. Lazarian, T. W. Shimwell et al.

We present the LOFAR Galaxy Cluster Ultra-Deep Field, in which 336 h of LOFAR observations at 120$-$168 MHz have been collected on the nearby ($z=0.080$) cluster Abell 2255. This massive and merging system is known to host spectacular radio emission from both cluster galaxies and the intracluster medium. Previous LOFAR observations revealed pervasive diffuse synchrotron emission extending from the cluster center to its dynamically active outskirts, tracing relativistic electrons propagating in l…

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astro-ph.SRastro-ph.GA

The Open Cluster Chemical Abundances and Mapping Survey: IX. Measuring the Effects of Stellar Diffusion in the Open Clusters NGC 752 and Ruprecht 147 using APOGEE

Diogo Souto, Taylor Spoo, Peter M. Frinchaboy, Katia Cunha, Jamie Tayar, Alessa Ibrahim Wiggins, Natalie Myers

A growing understanding of stellar processes that alter surface chemical abundances over time has opened new avenues for using these changes as probes of stellar properties. On the main sequence and near the turnoff, stellar surface abundances are affected by gravitational settling and radiative acceleration, collectively known as atomic diffusion. In this work, we use SDSS/APOGEE DR17/DR19 data to investigate atomic diffusion in the open clusters NGC~752 and Ruprecht~147, thereby constraining h…

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astro-ph.COastro-ph.GA

Measuring satellite galaxy subhalo masses in redMaPPer clusters with UNIONS weak lensing data

Roman Akhmetshyn, Jack Elvin-Poole, Michael J. Hudson, Isaac Cheng, Thomas de Boer, Sébastien Fabbro, Sam Farrens, Sacha Guerrini et al.

In this work, we present the observed galaxy-galaxy lensing signal of satellite galaxies in rich clusters obtained from the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS). Such observations are crucial for understanding dark matter halo physics and interaction dynamics in the cluster environment. Our goal is to investigate the tidal stripping of cluster subhalos. Theoretical predictions, supported by recent studies, suggest that as satellite galaxies fall into clusters, their dark ma…

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astro-ph.GA

Cold Stream Penetration of Virial Shocks: Fragmentation, Coagulation, and Disruption in the Hot Circumgalactic Medium

Zhiyuan Yao, Nir Mandelker, S. Peng Oh

Cold streams penetrating virial shocks of massive halos along cosmic web filaments are expected to fuel galaxy growth at high redshift, yet the physical processes governing their penetration remain uncertain. We investigate cylindrical cold streams penetrating a hot circumgalactic medium (CGM) using idealized three-dimensional simulations. We systematically vary the stream radius, Mach number, and initial pressure contrast between the stream and the CGM across three density contrasts, while cont…

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astro-ph.GAastro-ph.CO

Investigating anomalous microwave emission near G107.2+5.20 in Ku-band with the Green Bank Telescope

Jordan E. Shroyer, Bradley R. Johnson, Dillon J. Bass, L. Ilsedore Cleeves, Anna Dignan, Stuart E. Harper, Brian S. Mason, Andrey Moore et al.

Anomalous microwave emission (AME) is 30 GHz-peaking continuum emission thought to arise from spinning dust grains. Observations suggest that the local environment shapes the AME spectral energy distribution (SED), so building a spatially resolved sample of AME regions is a key step towards understanding its emission mechanism. Using the Green Bank Telescope Ku-band receiver, we obtained a ~1 arcmin resolution map of radius 1.25 deg centered on G107.2+5.20. Our first objective was to constrain t…

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gr-qcastro-ph.HEhep-th

Entropy release from Minkowski breaking in regular Schwarzschild black holes

Francisco S. N. Lobo, Manuel E. Rodrigues

The classical formation of a Schwarzschild black hole from a regular, non-singular configuration has recently been shown to be impossible within general relativity: the geometry inevitably develops a discontinuity at the origin, a phenomenon termed Minkowski breaking by Ovalle, Casadio, and Kamenshchik [PRD 113 (2026), 064042]. This obstruction signals that the transition to the Schwarzschild point mass must be a discrete, quantum event. We uncover the thermodynamic footprint of this transition.…

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astro-ph.GA

Magnesium isotope ratios in Milky Way and dwarf galaxy stars

M. McKenzie, S. Monty, D. Yong, C. Kobayashi, A. I. Karakas, P. E. Nissen, J. E. Norris, A. Rains et al.

Under the assumption of hierarchical galaxy formation, dwarf galaxies are the closest existing analogues to the high-redshift protogalaxies that merged to form the Milky Way. These low-mass systems serve as unique laboratories for studying nucleosynthetic channels, given that the chemical compositions of their stars play a pivotal role in constraining their chemical enrichment history. To date, stellar abundances in dwarf galaxies have focused almost exclusively on elemental abundance ratios. Wh…

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astro-ph.GA

The complex stellar system M 22: constraining the chemical enrichment from AGB stars using magnesium isotope ratios

M. McKenzie, D. Yong, A. I. Karakas, E. Wang, S. Monty, A. F. Marino, A. P. Milone, T. Nordlander et al.

The complex star cluster M 22 (NGC 6656) provides a unique opportunity for studying slow neutron-capture (s-process) nucleosynthesis at low metallicity due to its two stellar groups with distinct iron-peak and neutron-capture element abundances. Previous studies attribute these abundance differences to pollution from 3-6 solar-mass asymptotic giant branch (AGB) stars, which produce significant quantities of the neutron-rich Mg isotopes 25Mg and 26Mg. We report the first-ever measurements of Mg i…

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astro-ph.GA

The complex stellar system M 22: confirming abundance variations with high precision differential measurements

M. McKenzie, D. Yong, A. F. Marino, S. Monty, E. Wang, A. I. Karakas, A. P. Milone, M. V. Legnardi et al.

M 22 (NGC 6656) is a chemically complex globular cluster-like system reported to harbour heavy element abundance variations. However, the extent of these variations and the origin of this cluster is still debated. In this work, we investigate the chemical inhomogeneity of M 22 using differential line-by-line analysis of high-quality (R = 110,000, S/N = 300 per pixel at 514 nm) VLT/UVES spectra of six carefully chosen red giant branch stars. By achieving abundance uncertainties as low as ~0.01 de…

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physics.hist-phastro-ph.EP

The orientation of the Amazonian geoglyphs as a clue for their interpretation

Giulio Magli

Amazonian earthworks, also called geoglyphs, are thousands of man-made earthen structures, mostly of geometrical shape, which progressively emerged from the tropical forest due to progressive deforestation. They were probably built between the fifth century BC and the end of the first millennium AD, but archaeological investigation on the culture of their builders is yet at the beginning. Nevertheless, a ceremonial rather than practical function seems likely, at least for those having a very reg…

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astro-ph.IM

Update on the Magellan InfraRed Multi-Object Spectrograph (MIRMOS)

Maren Cosens, Nicholas P. Konidaris, Gwen C. Rudie, Andrew B. Newman, Leon Aslan, Robert Barkhouser, Christoph Birk, Julia Brady et al.

The Magellan InfraRed Multi-Object Spectrograph (MIRMOS) will be a next generation multi-object (MOS) and integral field spectrograph (IFS) for the 6.5m Magellan telescopes at Las Campanas Observatory in Chile. MIRMOS will perform R~3700 spectroscopy over a simultaneous wavelength range of 0.886-2.404um (Y, J, H, and K bands) in addition to imaging over the range of 0.7-0.886um. Target selection in the MOS mode is achieved through a cryogenic mechanism capable of making up to 92 slits over a 13'…

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astro-ph.IM

Update on the slicer IFU for the Magellan InfraRed Multi-Object Spectrograph (MIRMOS)

Maren Cosens, Patricio Schurter, Nicholas P. Konidaris, Gwen C. Rudie, Andrew B. Newman, Leon Aslan, Robert Barkhouser, Christoph Birk et al.

The Magellan InfraRed Multi-Object Spectrograph (MIRMOS) is a planned next generation multi-object and integral field spectrograph for the 6.5m Magellan telescopes at Las Campanas Observatory in Chile. MIRMOS will perform $\rm R\sim3700$ spectroscopy over a simultaneous wavelength range of 0.886 - 2.404um (Y, J, H, K bands) in addition to imaging over the range of 0.7 - 0.886um. The integral field mode of operation for MIRMOS will be achieved via an image slicer style integral field unit (IFU) l…

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astro-ph.SR

Observational Evidence for Counter-helicity Magnetic Reconnection in a Solar Eruption

Jinrui Chang, Yi Bi, Bo Yang, Junchao Hong, Jiayan Yang, Qingmei Wang

Magnetic reconnection between coronal magnetic systems carrying opposite self-helicity may play a role in solar eruptions, but observational evidence remains limited. We investigate an M7.0 flare in NOAA Active Region 13615 on 2024 March 28 using multiwavelength observations and nonlinear force-free field extrapolations. The reconstructed coronal field reveals a low-lying positive-helicity core field beneath an overlying magnetic system of opposite sign. During the eruption, the footpoint connec…

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astro-ph.IM

Development and characterization of a millimeter-wave cold load prototype

Ruya Cong, Junjie Zhou, Yu Xu, Xuefeng Lu, Jianrong Cai, Haoxuan Gao, Kang Zhang, Xingyuan Hou et al.

Superconducting transition-edge sensors (TESs) are crucial detectors for cosmic microwave background (CMB) observations and require stable and tunable millimeter-wave cold loads for optical-efficiency calibration. This work presents the design, fabrication, and preliminary characterization of a 4-20 K millimeter-wave cold load prototype intended for integration into the 1 K stage of a dilution refrigerator and subsequent 40/90 GHz CMB TES calibration experiments. Two absorber prototypes based on…

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astro-ph.IM

phoptic -- a Python package for reducing astronomical images

Zackery A. Irving, Noel Castro Segura, Diego Altamirano, Federico Vincentelli, Angel Castro, Romina P. Petrucci, Raul Michel, Adam B. Hill et al.

Publicly-available photometry pipelines make astronomical data reduction accessible to non-experts, reduce the margin for human error, and enable reproducible reduction. In many cases, bespoke reduction software is written on a per-instrument basis; this results in rigid pipelines that cannot be straightforwardly applied to data from other instruments. To alleviate this problem, we present phoptic, an open source photometry pipeline written in Python. phoptic began as a dedicated pipeline for th…

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