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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

A FLASH HI absorption search in compact sources in the pilot ASKAP interplanetary scintillation field

Paris E. Gordon-Hall, Emily F. Kerrison, Elizabeth K. Mahony, Elaine M. Sadler, Hyein Yoon, J. N. H. S. Aditya, James R. Allison, Rajan Chhetri et al.

In this pilot study, we use data from the First Large Absorption Survey in HI (FLASH) to search for redshifted HI 21cm absorption at $0.4<z<1$ towards 157 bright radio sources with Interplanetary Scintillation (IPS) measurements at 820MHz in a single field observed with the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope. The ASKAP IPS measurements, which use only 2.5 minutes of observing time in total, allow us to estimate the compactness of these radio sources on sub-arcse…

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astro-ph.GA

Environmental Imprints on the Assembly of the Cool Gas around Bright Cluster Galaxies

Runyu Zhu, Hu Zou, Taotao Fang, Enci Wang, Zeyu Chen, Zhaobin Chen, Weiyu Ding, Jinfu Gou et al.

Galaxy clusters represent extreme cosmic laboratories where environmental processes dramatically reshape their constituent galaxies, yet their effect on the gaseous halos of central galaxies remains poorly constrained. Here we present the first statistical mapping of cool gas around massive brightest cluster galaxies (BCGs) at $z\approx0.55$. Using Mg II absorption in stacked sight-line spectra from over a million background quasars observed by the Dark Energy Spectroscopic Instrument, we compar…

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astro-ph.SR

Pulsation harmonics reveal the origin of the century-old Blazhko effect

Jia-Shu Niu

The Blazhko effect -- a quasi-periodic modulation of pulsation amplitude and phase observed in all subtypes of RR Lyrae stars -- has defied physical explanation for over a century. Here we show that pulsation harmonics of the Blazhko RRab star V783 Cyg, traditionally regarded as passive replicas of the fundamental mode, encode a direct observational signature of the effect's origin. Using Kepler short-cadence photometry, we identify a subset of harmonics -- here termed ``disharmonized harmonics'…

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astro-ph.HE

Pulsar anti-glitches: starquakes driven by magnetism?

Hanyuan Long, Ruipeng Lu, Weiyang Wang, Shunshun Cao, Hao Tong, Han Yue, Renxin Xu

In the conventional starquake model of pulsar glitches, it is usually assumed that such events arise from fault slip induced by the self-gravity of compact objects. This inevitably decreases the moment of inertia, producing a glitch with an amplitude of only $Δν/ν> 0$. However, an increasing number of anti-glitches ($Δν/ν< 0$) have been observed in extremely magnetized pulsars, the magnetars, and this cannot be explained by that framework. In the present study, we hypothesis that magnetic stress…

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astro-ph.GA

Testing the recovery of the NGC 6505 Einstein ring in deep OSN 1.5-m imaging

Homer Dávila Gutiérrez, Julio Carlos Bertua Marasca, Alejandro Heredia Teva, Irene Naranjo Arroyo, Fernando Núñez Martínez, Miguel Ruiz Travesí, Eugenio Grande Sáez

The discovery of a complete Einstein ring around the nearby elliptical galaxy NGC 6505 (z = 0.042) by the Euclid mission provides a rare, precisely characterised low-redshift strong lens. Its Einstein radius of 2.500 arcsec is comparable to the angular resolution attainable from typical mid-aperture ground-based facilities, which makes the recoverability of the ring from the ground an open practical question. We test whether the ring can be recovered in deep Cousins-R imaging of NGC 6505 obtaine…

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physics.plasm-phphysics.space-ph

Exact Solution of the Direct and Inverse Dynamo Problem in the Expanding Plasma Ball

Yurii V. Dumin

It was found that the differential equation of dynamo effect (i.e., generation of the electric fields and currents) in a uniformly-expanding plasma ball with strongly anisotropic conductivity possesses the unique mathematical property: namely, the spectrum of its eigenvalues is universal and independent of physical parameters of the medium. As a result, it becomes possible to introduce a special set of eigenfunctions - which we called the generalized spherical functions - that can be used to sol…

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physics.ao-phastro-ph.EPnlin.AO

Modeling the response of the marine carbon cycle to extreme CO$_2$ injection events

Punit Gandhi, Rowan Lockwood, Corinne Myers, Parimita Roy, Ivan Sudakow, James Witts, Hao Helen Zhang

We explore how the response of a conceptual model of the marine carbon cycle depends on the way in which carbon is injected from the atmosphere. We find that, for single-injection pulses, the threshold amount required for a large response of the excitable system depends on pulse duration but not on its specific form. We do, however, see differences in the number of large transient responses in carbon and, correspondingly, the duration of the response for different pulse shapes. These differences…

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astro-ph.GA

A differentiable hydrodynamical approach to the Milky Way bar pattern speed with CO longitude--velocity data

Junichi Baba, Kohei Hattori

We present a differentiable hydrodynamical framework for modeling barred gas flow in the Milky Way and constraining broad low-loss regions in bar-pattern-speed parameter space from Galactic longitude--velocity data. The method evolves a neutral-gas disk in a fixed barred potential, projects it into longitude--velocity ($\ell$--$v$) space, and compares predicted and target maps using a cosine-distance loss applied to processed and masked maps. This emphasizes large-scale morphology rather than th…

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astro-ph.GA

Discovery of a gravitational arc candidate at photometric redshift 4.4 in MACS J0308.9+2645 from a catalogue-based search of JWST imaging

Homer Dávila Gutiérrez

We report a strong gravitational arc (A1) in the massive Reionization Lensing Cluster Survey (RELICS) cluster MACS J0308.9+2645 (z_l = 0.356), identified in public JWST/NIRCam imaging from programme GO-5293. A1 is an extended, curved, tangentially aligned source (axis ratio a/b = 6.5, catalogue length 3.9 arcsec) located 50.9 arcsec from the cluster X-ray centre. Its six-band (1.15-4.10 micron) photometry yields a photometric redshift of z_phot = 4.4 (+0.1/-0.3), with P(z > 3) = 0.99. Using the…

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astro-ph.IM

The Interstellar Laser Beacons Hypothesis and the Cosmic Lighthouses Project

Daniel Apai, Chia-Lung Lin, Kevin Wagner

In this paper, we argue that in a realistic, resource-limited scenario senders whose intent is to maximize successful communication at the lowest cost will utilize very long-lived, pulsed beacons. Further, we argue that mass-producible laser beacons with simpler technology ($μ$s or ms pulses instead of ultrashort fs pulses) are more optimal if placed on interstellar orbits. Our extensive, existing surveys are mostly blind to the $μ$s/ms-second universe and to such beacons. We show, however, that…

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astro-ph.EP

TESS Photometry and Radial Velocity Analysis of the sub-Neptune Exoplanet π Mensae c and the Wider π Mensae Planetary System

Skylar S. Larsen, Jake D. Turner, Nikole K. Lewis, Maryame El Moutamid, Diana Solano-Oropeza, Lili Alderson, V. Abby Boehm, Daniel A. Yahalomi et al.

Exoplanet characterization relies on precise measurements of planetary orbital and physical parameters. This is particularly important for planetary dynamics and atmospheric evolution, as orbital parameters help constrain system evolution, resolve ambiguities, and gauge atmospheric retention. The first exoplanet discovered by the Transiting Exoplanet Survey Satellite (TESS), $π$ Men c, is a warm sub-Neptune orbiting a bright Sun-like star in a system containing (at least) one other planet with a…

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astro-ph.GAastro-ph.HE

Illuminating M82: Simulating X-ray Emission from Galactic Winds in a Starburst Galaxy

Allison Lin, Lachlan Lancaster, Viraj Pandya, Drummond B. Fielding, Greg L. Bryan, John A. ZuHone, Sebastian Lopez, Laura A. Lopez et al.

We generate mock X-ray observations from a suite of idealized high-resolution ($\sim 4$ pc), tall-box ($\sim 2 \times 2 \times 8$ kpc$^3$) simulations of star formation driven galactic winds in an M82-like system, varying the spatial resolution as well as the strength and distribution of supernova (SN) energy injection. We compare our mock X-ray observations with deep Chandra observations of the hot plasma around M82. While the simulated total X-ray luminosity, $L_X$, increases with resolution a…

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astro-ph.EPastro-ph.GA

MOA-2020-BLG-108Lb: A Giant Planet Beyond the Snow Line of a Low-Mass Lens Near the Lower Boundary of the Mass-Ratio Desert

Yuki K. Satoh, David P. Bennett, Takahiro Sumi, Ian A. Bond, Nicholas J. Rattenbury, Daisuke Suzuki, Naoki Koshimoto, Shota Miyazaki et al.

We present an analysis of the microlensing event MOA-2020-BLG-108, which was discovered in June 2020 by the MOA collaboration toward the Galactic bulge. The observed light curve shows significant deviations from the standard single-lens single-source model. We find two degenerate binary-lens single-source solutions, corresponding to the wide and close configurations, with a companion-to-host mass ratio of $q\sim0.02$ and projected host--companion separations of $s=1.33\pm0.01$ and $s=0.76\pm0.01…

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astro-ph.GA

Tracing cosmic star formation history through radio continuum spectral energy distribution and non-thermal emission

Fangxia An, Fatemeh S. Tabatabaei, Nick Seymour, Maryam Khademi, Zunli Yuan, Wenjie Wang, Joe A. Grundy, Mark T. Sargent et al.

As a tracer of massive star formation unaffected by dust, the radio continuum emission provides a unique window into the formation of the first stars and galaxies in the Universe. Recent observations show that the integrated rest-frame mid-radio (~1-10 GHz) luminosity of galaxies serves as one of the most robust tracers of the star formation rate (SFR). These studies further demonstrate that the synchrotron spectral index and the shape of the radio spectral energy distribution (SED) evolves with…

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astro-ph.EPastro-ph.SR

I Can Do It With A Broken Planetesimal: Characterising the planetary debris in heavily polluted cool white dwarfs

Anna-Maria Cutolo, Boris T. Gänsicke, Andrew Swan, Andrew M. Buchan, Jamie T. Williams, Detlev Koester, Paula Izquierdo, Mark A. Hollands et al.

We present the analysis of four cool and strongly metal-polluted H-atmosphere white dwarfs observed with X-shooter. We compared their atmospheric parameters obtained from spectroscopy, photometry and a hybrid method, finding a difference of up to $\simeq160$ K in $T_\mathrm{eff}$, and $\simeq0.3$ dex in $\log g$, between the three analyses. We adopt the $T_\mathrm{eff}$ and $\log g$ from the photometric analysis, and subsequently measured the metal abundances of the photospheric elements from sp…

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astro-ph.GA

Determination of kinematic distances of WISE & SMGPS H II regions in the Galactic plane using SEDIGISM cloud association

Moses Langa, Mark Thompson, Andrew Rigby, Gwenllian Williams, Mubela Mutale, Cristobal Bordiu, Simone Riggi, Willice Obonyo et al.

One of the fundamental requirements for studying and understanding Galactic structure and massive star formation is accurate distances to H II regions. However, most distance assignments are hampered by kinematic distance ambiguity (KDA), sparse parallax measurements, and the large number of radio continuum sources lacking velocity and distance measurements. We present a kinematic distance determination method via cloud association, linking H II regions from the Wide-field Infrared Survey Explor…

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astro-ph.HEastro-ph.SR

Superlinear Type II Superluminous Supernovae 2017fck and 2019cmv: A Possible Origin from Interacting Thermonuclear Supernovae

Daichi Hiramatsu, Takashi J. Moriya, D. Andrew Howell, Iair Arcavi, Jamison Burke, Griffin Hosseinzadeh, Curtis McCully, Stefano Valenti et al.

Additional power sources to traditional supernovae (SNe) are necessary to account for the extreme luminosities of superluminous SNe (SLSNe). A main power source for hydrogen-rich SLSNe (SLSNe-II) is thought to be circumstellar material (CSM) interaction. However, the nature of underlying SNe and their progenitor systems remain elusive as they are hidden below strong CSM signatures. Here, we present optical photometry and spectroscopy of SLSNe-II 2017fck and 2019cmv. They are characterized by pos…

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astro-ph.HEastro-ph.IM

Mitigating the Timing Impact of Anomalous Pulse Profile Shape Variability in PSR J1713+0747 with Gaussian Component Modeling

Shania A. Nichols, Michael T. Lam, Gabriella Agazie, Anjana Ashok, Jeremy G. Baier, H. Thankful Cromartie, Kathryn Crowter, Megan E. DeCesar et al.

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) achieves sub-microsecond timing precision for several millisecond pulsars in its pulsar timing array (PTA) with the objective of detecting and characterizing nanohertz gravitational waves. PSR J1713+0747 is one of the most precisely timed pulsars in the array, achieving sub-microsecond timing precision. However, in April 2021, PSR J1713+0747 underwent a sudden and unusual change in pulse shape that disrupted its timing s…

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astro-ph.SR

Population demographics of post-interaction WDMS binaries: From common envelope evolution to stable mass transfer

Natsuko Yamaguchi, Kareem El-Badry, Cheyanne Shariat

Close white dwarf (WD) + main-sequence (MS) binaries are end products of mass transfer (MT) that occurred when the WD progenitor was a giant, making their population demographics a powerful probe of binary evolution. Several recent works have constructed samples of WD+MS binaries with well-understood selection functions using data from wide-field surveys. These include (a) au-scale astrometric binaries from Gaia that can be shown to contain a WD on dynamical grounds, (b) au-scale astrometric bin…

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astro-ph.GAastro-ph.HEastro-ph.SR

The JADES Transient Survey III: Linking Core-Collapse Supernova Rates to Cosmic Star Formation

Christian Vassallo, Seppo Mattila, Christa DeCoursey, Louis-Gregory Strolger, Erkki Kankare, Max M. Briel, Eiichi Egami, Iikka Mäntynen et al.

We investigate how core-collapse supernova (CCSN) rates trace the star-formation rate densities (SFRDs) over the redshift range $0 \le z \le 5$. For this we use new high-redshift results from the James Webb Space Telescope Advanced Deep Extragalactic Survey (JADES) Transient Survey (JTS, see the companion paper by DeCoursey et al. 2026), together with published CCSN rates. Using the observed CCSN rates to constrain the CCSN production efficiency relating SFRDs to CCSN rates, we examine how the i…

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astro-ph.GAastro-ph.CO

Galaxy mergers drive enhancements in ionization states

A. Le Reste, K. B. Mantha

Recent studies have suggested that galaxy mergers may help drive the escape of ionizing photons from galaxies. However, the ionization properties of merging galaxies have not yet been systematically studied across the full merger sequence in a large, well-defined sample. Here, we investigate the impact of mergers on the line ratio $\rm{O}_{32}$ tracing the ionization state and study its evolution as a function of merger progression. We identify 7641 galaxy mergers with robust ($\rm{SNR}>3$) emis…

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astro-ph.GAastro-ph.HE

The JADES Transient Survey II: Volumetric Supernova Rates out to z~5

Christa DeCoursey, Christian Vassallo, Louis-Gregory Strolger, Justin D. R. Pierel, Eiichi Egami, Seppo Mattila, Armin Rest, David A. Coulter et al.

The JADES Transient Survey (JTS) identified 83 supernova (SN) candidates in the JADES Deep Field, a $\sim$25 arcmin$^2$ region with deep ($\sim$30 mag) multi-band, multi-epoch JWST/NIRCam coverage. We use this sample to derive the first volumetric core-collapse (CC) SN and Type Ia (SN Ia) rates in the $z$$\sim$2-5 range. Many of these SNe are photometrically classified from single-epoch photometry (i.e., single spectral energy distributions (SEDs)), so we simulate and classify $\sim$23,000 CC SN…

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astro-ph.GA

The onset of stellar bars at Cosmic Noon. Bar-driven quenching and AGN co-evolution in a mature disc galaxy

Luca Costantin, Lorenzo Morelli, Cristina Cabello, Virginia Cuomo, Michele Perna, J. Alfonso L. Aguerri, Mahmood Roshan, Edoardo Borsato et al.

Observations with the JWST revealed an unexpected abundance of barred galaxies at Cosmic Noon. However, the physical properties of these early bars are almost unconstrained, as it is their impact in the structural evolution of high-z disc galaxies. In this work, we derived the stellar populations of EGS-24154, a barred spiral galaxy at $z=1.17$. First, we investigated the role of the stellar bar in the early assembly history and structural evolution of the galaxy. Second, we studied the properti…

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astro-ph.EPastro-ph.IM

Biosignature detectability on transiting habitable worlds with ELT/ANDES

E. Kurzawa-Ferrandez, A. Bello-Arufe, R. Hu

The search for life beyond the Solar System is at a turning point, transitioning from theoretical predictions to observations enabled by next-generation observatories. The Extremely Large Telescope (ELT) will host the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), optimized for visible-to-near-infrared high-resolution spectroscopy. We present a simulation--detection pipeline and evaluate the detectability of CO$_2$, H$_2$O, and the biosignature gases O$_2$ and CH$_4$ in high-resolution…

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astro-ph.EPastro-ph.GAastro-ph.SR

Probing the Innermost Region of the V883 Ori Disk Using ALMA Band 1 Methanol Line Observations

Yoshihide Yamato, Shota Notsu, Rui Zhuang, Yuri Aikawa, Nami Sakai

The snowlines of major volatiles in protoplanetary disks play a pivotal role in dust evolutions and volatile delivery to nascent planetary systems. In this paper, we report the Atacama Large Millimeter/submillimeter Array Band 1 ($\approx7.5\,\mathrm{mm}$) observations of methanol (CH$_3$OH) emission lines in the disk around the FU-Ori type star V883 Ori, where accretion outburst heats the disk and the majority of ices has sublimated. We detect three CH$_3$OH emission lines at an angular resolut…

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math-phastro-ph.EP

Expansion of the planetary Hamiltonian for small eccentricities and inclinations: a vector formalism

Federico Mogavero

We revisit the classical expansion of the planetary Hamiltonian for small eccentricities and mutual inclinations of the orbits, presenting a derivation based entirely on vector formalism. We demonstrate that the secular part of the disturbing function, as well as any other Fourier harmonic, can be expressed in terms of scalar products of vectors lying in the system's invariant plane. Furthermore, we show how to express any such term using the angular momentum and eccentricity vectors of the orbi…

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astro-ph.GAhep-ph

A Universal Distribution of Dark Matter in Milky Way-like galaxies and How to Infer It

Sam Cheng-Tse Huang, Matthew R. Buckley, Justin I. Read, David Shih

The phase-space density of dark matter within the Milky Way is a key quantity that encodes information about the nature of the dark sector. The local phase-space density is also required to properly interpret the results of dark matter direct detection experiments. However, there are at present few observational constraints. In this paper, we show that a simple coordinate transformation reveals a near-universal DM phase-space distribution function among three independent suites of cosmological s…

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astro-ph.GAastro-ph.SRhep-ph

Evolution of Binaries Under Stochastic Perturbations

Andrea Caputo, Giovanni Maria Tomaselli, Chris Hamilton

We develop a general Fokker-Planck framework describing the dynamical evolution of Keplerian binaries subjected to stochastic perturbations. The formalism provides an algorithmic way to obtain the Fokker-Planck drift and diffusion coefficients of any set of orbital variables given the statistics of the perturbations. We apply the method to three physically distinct regimes: adiabatic tidal perturbations, white-noise tidal perturbations, and impulsive encounters with a third body of arbitrary den…

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astro-ph.EP

Modeling the Evolution of Protoplanetary Disks: Two Pathways from Gravitational Instability to MHD Wind-Driven Accretion

Yang Ni, Wenrui Xu, Xue-Ning Bai

The global evolution of protoplanetary disks sets the initial conditions for planet formation. However, most models focus on individual evolutionary phases, with idealized initial conditions and oversimplified prescriptions for angular momentum transport and thermodynamics. We present a more realistic semi-two-dimensional ($1+1$D) model incorporating gravitational instability (GI), magnetohydrodynamic (MHD) winds, magneto-rotational instability (MRI), stellar irradiation, self-shadowing, and rad…

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astro-ph.COastro-ph.HEhep-ph

Signatures of $10-10^4\,{\rm M}_{\odot}$ Dark Matter halos in LISA via Stochastic Diffraction

Han Gil Choi, Juan Urrutia, Miguel Zumalacárregui

Cold Dark Matter predicts a population of low-mass halos which are sensitive to its fundamental nature and the primordial power spectrum, yet remain undetected. Although elusive, their discovery may be possible thanks to wave-optics lensing of gravitational waves (GWs) by the superposition of many halos along the line of sight. We study the statistical properties of stochastic diffractive lensing, which imprints correlated fluctuations on the amplitude and phase of the original waveform. The sto…

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