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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SRphysics.plasm-ph

The Diagnostic Temperature Discrepancy as a Kinetic Measurement: Shape, Transport, and Termination of the Suprathermal Electron Tail

Victor Edmonds

Two standard thermometers applied to the same quiet-Sun corona disagree by a stable factor: radio brightness reads about 0.6 MK while ionization- and scale-height-based diagnostics read about 1.5 MK, a ratio of 2.4 +/- 0.3 over eight years. We argue this discrepancy is not an anomaly awaiting reconciliation but a kinetic measurement, and we read it three times: for the shape of the electron distribution, for its origin, and for the energy where it must end. First, a temperature diagnostic is a p…

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astro-ph.HE

Same explosion, many faces: numerical modeling reveals viewing angle as a driver of diversity for core-collapse SNe in binary systems

Soham Mandal, Raphael Baer-way, Shazrene Mohamed, Irene Salmaso, Poonam Chandra, Maryam Modjaz

Observable properties of core-collapse supernovae (CCSNe) depend sensitively on the circumstellar material (CSM) formed by pre-explosion mass loss from the progenitor star. Since a large fraction of CCSN progenitors reside in binaries, both the progenitor structure and surrounding CSM can be significantly impacted by binary interaction. Yet, its impact on the observed CCSN landscape remains poorly constrained. In this work, we investigate CCSNe from binary systems undergoing stable Roche lobe ov…

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hep-phastro-ph.COastro-ph.GA

Dynamical flattening of halo density cusps by Q-ball dark matter

Alexander Libanov, Sergey Troitsky

Cold, collisionless dark matter successfully explains a wide range of observations, including the formation of large-scale structure. Nevertheless, tensions remain on small, galactic scales, most notably the cusp-core, or inner-mass-deficit, problem and the diversity of inner rotation-curve shapes and central densities at fixed halo mass. These observations suggest that additional dark-sector physics may affect the inner structure of halos, although no generally accepted explanation has yet emer…

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physics.hist-phastro-ph.IMphysics.class-phphysics.ed-ph

De mora luminis: Roemer's discovery 350 years later

Fabio Falchi, Riccardo Furgoni, Paolo Gattillo, Maurizio Francesio

350 years from the 1676 announcement of the Roemer's discovery that light propagates with finite speed, we present our observations using eyes with telescopes having similar resolution compared to those in the late 17th century. We confirmed that Roemer's method is valid and gives reasonable values for the speed of light c, within about 10 per cent of the modern value for our measurements, even with the simplest modelling technique, using uniform circular motions. We found that increasing the co…

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astro-ph.HEastro-ph.IM

Uncertainty-Aware Tidal Disruption Event Classification : A Host-Agnostic Probabilistic Random Forest Approach

Vysakh Anilkumar, Sjoert van Velzen, Marek Kowalski, Simeon Reusch

The classification of Tidal Disruption Events in large-scale photometric surveys is challenging because deterministic machine learning models produce overconfident misclassifications under varying data quality and low signal-to-noise conditions. Existing lightcurve-based approaches fail to incorporate measurement uncertainties, consequently generating brittle outputs. We present a host-agnostic, uncertainty-aware classification framework using a Probabilistic Random Forest (PRF). Our pipeline ex…

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astro-ph.SR

PRICM3: A novel Polarization Ratio framework for three-dimensional CME reconstruction

Yara De Leo, Manuela Temmer, Fernando M. López, Sarah E. Gibson, Hebe Cremades, Leonardo Di Lorenzo, Roberto Susino, Marco Romoli et al.

Coronal mass ejections (CMEs) are inherently three-dimensional (3D), but traditional white-light coronagraphs provide only two-dimensional (2D) projections. While the Polarization Ratio Technique (PRT) utilizes Thomson scattering to infer proxy 3D plasma locations, its results are typically limited to 2D topographical maps, hindering geometric interpretation. To address this, we introduce PRICM3 (Polarization Ratio Integrated CME Mapper in 3D), a framework that converts PRT-derived maps into exp…

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astro-ph.GAastro-ph.HE

X-ray Absorption Variability in NGC 1142: Another Constraint on the Nature of the Torus/Broad-Line Region in Active Galactic Nuclei

Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Vittoria E. Gianolli, Xiurui Zhao, Marco Ajello, Indrani Pal, Andrealuna Pizzetti et al.

The physics, geometry, and kinematics of the gas and dust surrounding the central engine of active galactic nuclei (AGN) are not well understood. In some sources, this material obscures the coronal X-ray emission, allowing its line-of-sight column density ($N_H$) to be measured. Many sources display $N_H$ variability across multiple epochs. Studying this variability can provide information about the distribution and dynamics of the obscuring material. Particularly, previous works have shown that…

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astro-ph.IM

DB-Bench: Benchmarking Deblenders for LSST DESC Using the Blending ToolKit

Aidan Berres, Grant Merz, Xin Liu, the LSST Dark Energy Science Collaboration

Blending will be a major source of systematic uncertainty in downstream science analyses of LSST data. We benchmark the performance of several deblenders, leveraging the Blending ToolKit (BTK) to perform rigorous, end-to-end testing. This benchmark incorporates key deblending algorithms, including SourceExtractor, SCARLET, and DeepDISC, with the goal of comparing their effectiveness in handling blended galaxy images from LSST/Rubin simulations. A key focus is characterizing algorithm performance…

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astro-ph.IM

DB-Bench: Benchmarking Deblenders for LSST DESC Using the Blending ToolKit

Aidan Berres, Grant Merz, Xin Liu, Éric Aubourg, Cécile Roucelle, the LSST Dark Energy Science Collaboration

Blending will be a major source of systematic uncertainty in downstream science analyses of LSST data. We benchmark the performance of several deblenders, leveraging the Blending ToolKit (BTK) to perform rigorous, end-to-end testing. This benchmark incorporates key deblending algorithms, including SourceExtractor, SCARLET, and DeepDISC, with the goal of comparing their effectiveness in handling blended galaxy images from LSST/Rubin simulations. A key focus is characterizing algorithm performance…

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astro-ph.IM

Statistical treatment of searches for counterparts of positionally-uncertain astrophysical sources: from flux upper limits to detection

Julian Sitarek, Abelardo Moralejo, Juan Jiménez Quiles, Giacomo D'Amico, Andrea Simongini, Antonio Stamerra

Rapid growth of the multimessenger and multiwavelength astrophysics had led to an increasing number of observations of the same events with instruments with different point spread functions. In particular pointing instruments with good angular resolution are used to pin-point the source of poorly-localized alert. In case no clear detection of the source counterpart is reached, the interpretation of the results requires statistical analysis. We investigate two approaches using the probability den…

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astro-ph.SR

Magnetic Reconnection Process in Partially Ionized Fluids: Insights from the Solar Chromosphere

Adrian R. Montañez-Lobo, Fabio D. Lora-Clavijo

Magnetic reconnection converts stored magnetic energy into kinetic energy, heat, and radiation. While extensively studied in fully ionized plasmas, observations show that ionization and recombination also play a role by modifying the local plasma resistivity and enabling additional heating channels. This study examines magnetic reconnection in the partially ionized solar chromosphere, analyzing its morphology and energy releases with attention to elastic collisions, ionization, and recombination…

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astro-ph.HEastro-ph.COnucl-th

Binary neutron stars in the next-generation era: Multi-messenger detection prospects and constraints on the equation of state, mass distribution, and cosmology

Hauke Koehn, Thibeau Wouters, Gilad Sadeh, Peter T. H. Pang, Mattia Bulla, Chris Van Den Broeck, Michael W. Coughlin, Tim Dietrich et al.

Next-generation gravitational-wave (GW) observatories will provide crucial insights into the nature of neutron star (NS) matter and the cosmological expansion history. We estimate the number of multi-messenger detections from binary neutron stars (BNS) with the Einstein Telescope (ET) and Cosmic Explorer (CE), and project the resulting constraints on the equation of state (EOS), BNS mass distribution, and cosmology via joint hierarchical Bayesian inference. Assuming a local merger rate of 106.6…

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astro-ph.HEhep-phnucl-th

Estimating amplitude of matter density fluctuations in solar and supernova models using neutrino flavor evolution

Caroline Laber-Smith, Hansen Torres, Lily Newkirk, Dhriti Rathod, A. Baha Balantekin, Amol V. Patwardhan

Neutrinos can undergo substantial flavor evolution between their production in astrophysical sources-such as the Sun and core-collapse supernovae-and their subsequent detection in terrestrial detectors. This flavor evolution is strongly influenced by the environment that the neutrinos interact with, making them useful astrophysical messengers capable of potentially carrying information about the properties of the source wherein they are produced. In this work, we apply the framework of statistic…

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astro-ph.IMastro-ph.EP

Segment-level thermal sensitivity analysis for exo-Earth coronagraphy with segmented space telescopes

Ananya Sahoo, Laurent Pueyo, Iva Laginja, Bryony F. Nickson, Leonid Pogorelyuk, Laura E. Coyle, Rémi Soummer, Matthew East et al.

Direct imaging and characterization of Earth-like planets require ultra-stable wavefronts to achieve a starlight suppression level of 100 parts per trillion (ppt) in the coronagraphic dark region of the host star. Thermal drifts in the telescope may affect the wavefront stability. In this context, we present a segment-level thermal stability error budget for segmented space telescopes crucial to Earth-like planet detection and specify requirements for an ultra-stable telescope. Our study utilize…

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astro-ph.EP

Kilometre-scale Jovian moon characterized for a potential JUICE flyby

Juan Luis Rizos, Jose Maria Gomez-Limon, Yucel Kilic, Altair R. Gomes-Junior, Jose Luis Ortiz, Nicolas Morales, Alvaro Alvarez-Candal, Pasquale Palumbo et al.

Jupiter's irregular satellites are thought to be relics of early Solar System planetesimals. However, their small sizes, large distances from Earth and close angular proximity to Jupiter make them difficult to characterize remotely. Here we report multi-instrument observations of kilometre-sized Kallichore, the only irregular moon of Jupiter amenable to a close flyby by ESA's Jupiter Icy Moons Explorer (JUICE), whose astrometric and physical properties were still poorly constrained. We used Hubb…

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astro-ph.COastro-ph.HEgr-qc

Understanding constraints on primordial mass black holes made of dark matter using fast radio bursts

Surajit Kalita, Shruti Bhatporia, Amanda Weltman

In recent decades, a multitude of modified gravity theories have been proposed to address a variety of cosmological and astrophysical problems. While many of these theories remain viable, observational constraints on their parameters are increasingly stringent. Fast Radio Bursts (FRBs), in particular, have emerged as powerful probes of cosmology and fundamental physics. This study investigates the implications of a generic modified gravity theory for gravitational lensing by FRBs. By analyzing t…

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astro-ph.GA

JWST's Constraints on the Substellar IMF in NGC 2024

K. L. Luhman

A recent study has reported the detection of a turnover in the initial mass function (IMF) below 12 Mjup and the possible detection of a minimum mass near 3 Mjup in the heavily embedded cluster NGC 2024 ( =2 Mjup for Ak>=1), so the minimum mass of the IMF has not been detected. It is not possible to measure a reliable substellar IMF from the NIRCam images because of the small number of brown dwarfs encompassed by them, a bias against objects at lower masses due to the high extinctions, and incom…

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gr-qcastro-ph.IM

Ab Initio Real-Time Gravitational-Wave Parameter Estimation

David Yallup, Metha Prathaban, James Alvey, Thomas C. K. Ng, Thibeau Wouters, Nikhil Sarin, Will Handley

We present a specialised GPU-native nested sampling kernel targeting rapid parameter estimation for gravitational wave inference problems. Building upon a Slice-within-Gibbs (SwiG) structure for rapid mixing, we investigate how far we can push baseline stochastic sampling techniques on modern GPU hardware. We demonstrate that for typical long-duration binary neutron star signals observed by the LIGO and Virgo detectors, we can achieve well calibrated posterior inference on the full uncompressed…

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astro-ph.IM

Exploring generative design AI tools for astronomical instrumentation: a CubeSat chassis case study

Younes Chahid, Tassos Aretos, Will Cochrane, Katherine Morris, David Isherwood, Zeshan Ali, Graham Wilks, Noah Schwartz et al.

Generative design artificial intelligence (AI) tools are currently used in multiple scientific fields, yet their adoption in mechanical engineering computer-aided design (CAD) remains limited due to a lack of disseminated case studies, limited availability of accessible tools, insufficient training in CAD data, the absence of universal editable file formats and more. Mechanical design for astronomical instrumentation faces increasing complexity in thermal, vibrational, and mechanical requirement…

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physics.geo-phastro-ph.EP

Calibrated uncertainty for wide-angle crustal models: how firmly is the Dharwar Craton Moho actually constrained?

Deepak Kumar, Laxmidhar Behera, Wojciech Czuba

Depth uncertainties for wide-angle crustal models are usually obtained by propagating an assumed picking error, yet picks from one shot gather are mutually dependent and velocity-depth trade-offs act at the level of the model class. We revisit the 210-km Perur-Chikmagalur profile across the Dharwar Craton using a permanently identified ledger of 2,000 primary P1-P2 first arrivals and 9,919 reflections from seven shots, with 852 later-turning P4 observations held aside for a conditional test. At…

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astro-ph.HE

Multiwavelength study of supernova remnants in the Circinus constellation with SRG/eROSITA

A. Khokhriakova, W. Becker

Supernova remnants (SNRs) are key tracers of stellar feedback and the chemical and dynamical evolution of the interstellar medium. However, identifying SNRs in complex regions remains challenging, particularly when only archival multi-wavelength data are available. We aim to search for previously unrecognized SNR candidates in the Circinus constellation by combining optical imaging, radio continuum data, and available SRG/eROSITA all-sky survey X-ray observations, to provide a prioritized list o…

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astro-ph.GA

Searching in HI for Massive Low Surface Brightness Galaxies: II. Completing the UGC Sample

Karen O'Neil, Wim van Driel, Stephan Schneider

Although Low Surface Brightness (LSB) galaxies are increasingly well studied, considerable uncertainty still exists as to both their range in properties and their evolutionary history. LSB galaxies provide a fascinating extreme in galaxy formation and evolution, allowing excellent tests of galaxy formation and evolution theories. Previously, our group successfully measured the HI gas and dynamical mass properties of 350 LSB galaxies, significantly increasing the number of known extreme LSB galax…

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astro-ph.GA

Bipolar HII regions Produced by Cloud-Cloud Collisions

Theotokis Georgatos, Anthony P. Whitworth, Richard Wünsch, Annie Zavagno

We use numerical experiments to explore two possibilities: (i) that Bipolar H II Regions are the result of Cloud-Cloud Collisions (CCCs), and (ii) that -- when allowance is made for the chaotic nature of such collisions, the short duration of the bipolar phase, and different viewing angles -- a large proportion of all H II Regions might be the aftermath of CCCs. To reduce the parameter space, our experiments only consider head-on collisions between two $500$ M$_\odot$ clouds, with three differen…

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astro-ph.SR

Detecting Solar-Like Oscillations in the Highest Mass TESS Giants

Noah J. Downing, Madeline Howell, Marc H. Pinsonneault, Rafael A. García, Dinil B. Palakkatharappil, Lina Borg, Savita Mathur

Red-giant asteroseismology yields precise stellar parameters, making it a powerful tool for studying stellar structure and evolution, as demonstrated by the Kepler mission. However, due to Kepler's limited field of view, it primarily sampled the more populous low-mass red giants found outside of the Galactic plane, leading to limited detections of red giants above $\rm 3\ M_{\odot}$. Here we use the all-sky TESS data to isolate 227 intermediate-mass candidates from large catalogs with a pre-sele…

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astro-ph.COastro-ph.GA

A study of the large-scale formation in the environment of A3266: Infalling groups, filaments, and a premerger cold front

J. Dietl, A. Veronica, T. H. Reiprich, F. Pacaud, Y. Zhao, J. S. Sanders, B. Seidel, M. C. H. Yeung et al.

Abell 3266 (A3266) is a dynamically active galaxy cluster embedded in a dense environment of galaxy groups and clusters at similar redshift. Data from the Spektrum Roentgen Gamma (SRG)/eROSITA all-sky survey enable the study of faint X-ray emission in cluster outskirts. We investigate the previously unexplored outskirts of A3266 out to $3R_{100}$, characterize its nearest neighboring galaxy group, and search for connecting filaments using X-ray emission and galaxy number density. We performed X-…

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astro-ph.HE

The First Measurement of Jet Collimation Profiles in an X-ray Binary: the Case of SS 433

Xi Yan, Lang Cui, Zsolt Paragi, Sándor Frey

While significant progress has been achieved in active galactic nuclei (AGN), jet collimation profiles in X-ray binaries (XRBs) have not been directly measured. Here we report the first measurement of jet collimation profiles in an XRB using very long baseline interferometry data from SS 433. The approaching jet exhibits a well-constrained quasi-parabolic profile in the 1995 and 1998 data, whereas the prominent local oscillations present in the 2000 jet-width measurements preclude a robust chara…

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astro-ph.HE

The First Measurement of Jet Collimation Profiles in an X-ray Binary: the Case of SS 433

Xi Yan, Lang Cui, Zsolt Paragi, Sándor Frey

While significant progress has been achieved in active galactic nuclei (AGN), jet collimation profiles in X-ray binaries (XRBs) have not been directly measured. Here we report the first measurement of jet collimation profiles in an XRB using very long baseline interferometry data from SS 433. The approaching jet exhibits a well-constrained quasi-parabolic profile in the 1995 and 1998 data, whereas the prominent local oscillations present in the 2000 jet-width measurements preclude a robust chara…

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astro-ph.EP

Characterizing the oxidation state of rocky exoplanets with the Large Interferometer for Exoplanets (LIFE)

Lorenzo Cesario, Tim Lichtenberg, Michiel Min, Lena Noack, Caroline Brachmann, Eleonora Alei, Sascha P. Quanz, LIFE Collaboration et al.

The oxidation state of rocky exoplanets is expected to play a fundamental role in shaping the chemical composition of their secondary atmospheres by influencing the chemical composition of volcanically released gasses. Distinguishing planetary redox states through direct atmospheric characterization would offer insight into the formation and evolution of secondary atmospheres on exoplanets and inform the background chemistry of putative biosignatures. The Large Interferometer For Exoplanets (LIF…

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astro-ph.HEastro-ph.GAastro-ph.SRnucl-th

Impact of Kaon Condensation on the Thermal Evolution of the CCO in HESS J1731--347 Supernova Remnant

D. G. Nanopoulos, P. S. Koliogiannis, V. Petousis, M. Veselsky, Ch. C. Moustakidis

Recent analyses of the central compact object in the HESS J1731--347 supernova remnant suggest an unusual combination of a low mass and small radius, while its thermal emission indicates a relatively high surface temperature at its estimated age. Reconciling these structural and thermal properties within a unified theoretical framework may provide important constraints on the equation of state and composition of dense matter. In this work, we investigate the thermal consequences of negatively ch…

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astro-ph.SR

Magnetic Field Stratification in Active-Region Plage from Ca II K and Ca II 8542 Å Spectropolarimetry

Iñigo Juanikorena Berasategi, Ernest Alsina Ballester, Javier Trujillo Bueno, Francisco A. Iglesias, Yusuke Kawabata, Juan Sebastián Castellanos Durán, Masahito Kubo, Alex Feller et al.

We investigate the height variation of the line-of-sight (LOS) magnetic field in solar active-region (AR) plage from the upper photosphere to the upper chromosphere using co-spatial ultraviolet (UV) and infrared (IR) spectropolarimetric observations from the Sunrise III stratospheric balloon flight. The Ca II K and Ca II 8542 Å lines provide complementary chromospheric diagnostics, while nearby Fe I lines sample photospheric layers. The LOS magnetic field is inferred from the intensity and circu…

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