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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.EP

A Spatial Map of the Atmospheric Limb of a Hot Jupiter

Lili Alderson, Hannah R. Wakeford, David Grant, Nikole K. Lewis, Avinash Verma, Jayesh Goyal, Mark Hammond, Daniel Valentine et al.

Planets are inherently three-dimensional objects shaped by their thermal structure and dynamics. Observations of transiting exoplanets have begun to uncover this three-dimensional nature, with JWST measuring their dayside atmosphere structure with eclipse mapping, and exploring spectroscopic asymmetries in the limbs of planets during transit. We apply the novel mapping method of transmission strings to the hot Jupiter WASP-17b. With this method, we are not only able to extract hemispheric limb a…

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gr-qcastro-ph.IM

Turning Selection Bias into a New Statistic: Asymmetry and Fringes of Lensed Gravitational Waves

Juno C. L. Chan, Elwin K. Y. Li

Gravitational waves (GWs) propagating across the Universe can be distorted by intervening lenses, producing characteristic wave-optics signatures. These effects are not incorporated into current matched-filtering searches and can therefore substantially reduce detection efficiency. The underlying mechanism is the signal-consistency test, which measures deviations between the observed and expected signal-to-noise ratio (SNR) distributions. We report a systematic study of the impact of gravitation…

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astro-ph.HE

Evidence for Distinct One-Off and Repeating Subpopulations in CHIME/FRB Catalog 2

Sloane Sirota, Duncan R. Lorimer

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has published its second catalog of 3,641 fast radio bursts (FRBs). While this sample includes 981 bursts from 83 repeating sources, only 2.3% of CHIME FRBs are observed to repeat. This raises the question of whether the FRB population truly consists of a single repeating population or includes a distinct subpopulation of one-off sources. We apply Simulation Based Inference (SBI), a likelihood-free machine learning framework, to model th…

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astro-ph.IMphysics.ao-ph

Establishing baseline model performances for optical turbulence forecasting

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

Accurate forecasting of optical turbulence (OT) is useful to optimise telescope scheduling and maximising observing efficiency, as the performance of adaptive optics systems strongly depends on turbulence conditions. While various numerical weather prediction and machine learning models are developed to predict these complex turbulence properties, properly evaluating their added value requires well-defined baseline reference models. This study establishes baseline performance thresholds for key…

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astro-ph.HE

The compact jets of the black hole X-ray binary Swift J1753.5-0127 during its 2023-2024 outburst

Noa Grollimund, Stéphane Corbel, Lauren Rhodes, David M. Russell, M. Cristina Baglio, Francesco Carotenuto, Tristan Bouchet, Payaswini Saikia et al.

X-ray binaries are excellent laboratories to study the coupling between accretion and ejection phenomena around compact objects through multiwavelength observations. Swift J1753.5-0127 is a black hole low-mass X-ray binary discovered in outburst in 2005 that remained active for 11 years, followed by two mini-outbursts. We investigate the behavior of the compact jets of Swift J1753.5-0127 during its 2023-2024 outburst. We report a dense multiwavelength monitoring in the radio, NIR/optical/UV and…

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astro-ph.HEhep-ph

Multimessenger Constraints on Nuclear Acceleration in Neutrino-Emitting Seyfert Coronae

Chengchao Yuan

High-energy neutrinos from Seyfert galaxies probe particle acceleration near supermassive black holes, but the accelerated nuclear composition remains uncertain. We connect stochastic acceleration to nuclear and radiative cascades to assess nuclear contributions. Acceleration and losses limit the energy per nucleon available to nuclear cascades; without secondary reacceleration, fragmentation cannot raise this scale. For NGC~1068, joint neutrino and gamma-ray constraints depend on the nuclear mi…

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astro-ph.GA

The Connection Between the Growth of Massive Black Holes and Their Dynamical Histories

Lee A. Whitaker, Michael Tremmel, Angelo Ricarte, Priyamvada Natarajan

Massive black holes (MBHs) grow through both gas accretion and mergers and it remains unclear how variations to MBH growth and dynamical histories contribute to the spread in empirical scaling relations between MBHs and their host galaxies. We examine the ex- and in-situ growth of MBHs within large-scale cosmological simulations and compare the evolution of an outlier population of under-grown MBHs to the general population. We use the Romulus25 uniform volume cosmological simulation and the Rom…

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astro-ph.GA

Cosmic Evolution Survey: LOFAR 144 MHz imaging of the COSMOS field

E. Vardoulaki, T. Shimwell, M. J. Hardcastle, L. Doukas, L. K. Morabito, C. L. Hale, M. T. Sargent, V. Smolčić et al.

We present the first deep, targeted LOFAR 144 MHz source catalogue of the COSMOS field, together with the first 144 MHz source counts in this field. The data comprise 48 h of observations. Over the 2.6 sq. deg. region adopted for the catalogue analysis, the final Dutch-array image reaches a median rms sensitivity of ~100 uJy/beam at an angular resolution of 15" x 6". The resulting catalogue contains 1984 radio sources; a peak S/N >= 5 selection is adopted for the resolved/unresolved classificati…

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astro-ph.SRastro-ph.GA

Anchoring the Chromospheric Activity$-$Rotation Relation: A Study of the Pleiades and Group X

A. Núñez, M. A. Agüeros, J. L. Curtis, C. A. Ospinal Achicanoy

We present a study of the rotation and the chromospheric H$α$ activity of low-mass stars in the $\approx$120 Myr-old Pleiades and the $\approx$400 Myr-old Group X open clusters. We combine published and new rotation periods ($P_\mathrm{rot}$) from TESS and ZTF, and use LAMOST, SDSS, and MDM spectra to measure H$α$ equivalent widths (EWs). While overall the Group X distributions of $P_\mathrm{rot}$ and EWs are as expected, detailed comparisons to the Pleiades and to the 700-Myr-old benchmark Prae…

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astro-ph.HEastro-ph.COastro-ph.GA

The ePESSTO+ census of ZTF nuclear transients. I. What flares in galactic nuclei?

E. Concepción, T. Petrushevska, G. Leloudas, D. Ilić, M. Gromadzki, S. Bhattacharyya, P. Charalampopoulos, A. Gomboc et al.

Transients in galactic nuclei arise from distinct processes, only some of which trace the supermassive black hole (SMBH). These include tidal disruption events (TDEs), changing-look active galactic nuclei, Bowen fluorescence flares (BFFs) and ambiguous nuclear transients, alongside supernovae that appear nuclear but are unrelated to the SMBH. Reliable classification requires spectroscopy, which will not scale to the alert volumes of the Legacy Survey of Space and Time (LSST). We aim to character…

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physics.ins-detphysics.space-ph

The Energetic Particle Detector Instrument on ELFIN

Colin Wilkins, Ryan Caron, Ethan Tsai, Chris Shaffer, Patrick Cruce, Maxwell Chung, Andrei Runov, Jiang Liu et al.

We present the design methodology, implementation, and data products of the Energetic Particle Detector (EPD) instrument on-board the Electron Losses and Fields Investigation (ELFIN) dual SmallSat mission. ELFIN was designed to study the time-evolution of energetic particle distributions in Earth's magnetosphere, having operated in polar Low Earth Orbit (LEO) from 2018 to 2022. Each satellite's instrument payload contained a pair of detector heads to sense differential-directional fluxes of 50 k…

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astro-ph.GAastro-ph.SR

Dynamical formation of dormant black holes: Predictions for Gaia DR4

Daniel Marín Pina, Michela Mapelli, Giuliano Iorio, Cecilia Sgalletta

Dormant black holes (dormant BHs, i.e., X-ray quiet binaries comprising a BH and a companion star) are probes of the effect of cluster dynamics and binary stellar evolution on compact-object binaries. A dozen dormant BH binaries are known, a number that will increase substantially with the upcoming Gaia Data Release 4 (DR4). Their origin is uncertain, and dynamical formation is proposed as one possible channel. Here, we study the formation of dormant BHs in low-mass star clusters, accounting for…

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astro-ph.GA

Massive double-exponential galaxies with extended LSB emission: An IllustrisTNG exploration II -are they unique?

Suchira Sarkar, Kanak Saha, Anshuman Borgohain

The massive disk galaxies (stellar mass >= 10^11 M_solar ) in the local universe (z < 0.1) encode challenging aspects of galaxy formation physics. We have studied one class of such galaxies - the giant low surface brightness galaxies (gLSBs) that show a hybrid morphology - a central Sersic, an inner high surface brightness, exponential stellar disk surrounded by an outer, extended low surface brightness disk, using large volume IllustrisTNG-100 simulation. This is motivated by the recent observa…

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astro-ph.SRastro-ph.EP

Star spots mimic the proposed abundance signatures of planet formation

Andrew R. Casey, Megan Bedell, Adam Wheeler, Julianne Dalcanton, Lily Zhao

Trends with stellar elemental abundances and condensation temperature have been proposed as a possible tracer of rocky planet formation. Here we present an alternative explanation, where we show that stellar activity (star spots) can also cause apparent abundance changes in refractory elements preferentially over volatile elements. This effect arises naturally from atomic physics: refractory (rocky; high-$T_c$) elements preferentially have low first-ionization potentials, with strong transitions…

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astro-ph.GAastro-ph.HE

Black hole spin-mass correlation and accretion disks at birth stage of dense star clusters

Zacharias Roupas

We review the accretion-driven channel of stellar black-hole growth and spin-up in gaseous star clusters, developed within the framework of our MSCA project "protoBH". Our detailed calculations involving semi-analytic modelling, dynamical and hydrodynamic simulations suggest that the growth and spin-up of initially low-mass stellar black holes is an integral element of the formation process of dense massive star clusters, such as the proto-globular clusters observed at high redshift. The black h…

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astro-ph.HEastro-ph.GA

Broadband non-thermal emission predictions based on 3D simulations of supernova explosions within active galactic nuclei jets

B. Longo, V. Bosch-Ramon, M. Perucho, J. M. Martí

Thermonuclear and core-collapse supernovae are statistically expected to happen within extragalactic jets, as these jets cross the inner regions of their host galaxies, and supernova ejecta-jet interactions can potentially lead to strong non-thermal activity. We model the non-thermal emission from a supernova interacting with a jet on kiloparsec scales, using detailed numerical simulations of the interaction. Using a post-processing method, we applied a non-thermal model of the acceleration and…

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gr-qcastro-ph.HE

Tidal Excitation of Relativistic Stars

Zhiqiang Miao, Junquan Su, Neev Khera, Huan Yang

How a relativistic star responds to a time-dependent tide has lacked a first-principles counterpart of the Newtonian normal-mode expansion. In general relativity, the tidal field is gauge sensitive, radiative modes are non-Hermitian and incomplete, and the direct and late-time responses are intrinsically nonmodal. In this work we present, to our knowledge, the first causal relativistic theory that treats all of these components on equal footing. We first develop the spectral decomposition of the…

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astro-ph.GA

EDGE-INFERNO: The chemical signatures of assembly history in reionization fossils

Eric P. Andersson, Martin P. Rey, Alexander P. Ji, Justin I. Read, Oscar Agertz, Alexander H. Riley, Stacy Y. Kim, Astha Chaturvedi et al.

In galaxies, stellar populations represent a superposition of both in situ and accreted components, tracing internal chemical evolution as well as the histories of merged satellites. We investigate how assembly history shapes the chemical properties of present-day stellar populations in low-mass dwarf galaxies. We analyze a suite of EDGE-INFERNO star-by-star cosmological zoom-in simulations of galaxies with present-day halo mass $\sim1.4\times10^9\,{\rm M}_{\odot}$. We systematically vary galaxy…

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astro-ph.IM

Ushering in high angular resolution observatories in the far-infrared: The case for a double-Fourier interferometer

C. S. Benson, M. Bonato, T. A. Davis, T. Essinger-Hileman, D. Farrah, W. Grainger, D. Leisawitz, H. Matsuo et al.

A far-infrared (far-IR) interferometer from a space-based platform would bring about a transformational improvement in the spatial detail of astronomical observations that are inaccessible from ground-based observatories. This orders-of-magnitude improvement would significantly advance studies of newly formed and mature exoplanetary systems and their potential for supporting life, the earliest stages of star formation, and the evolution of galaxies up to the peak of the Universe's star formation…

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astro-ph.HEastro-ph.GA

Delving into the depths of NGC 3783 with XRISM VI. Evidence for a failed wind based on Fe xxv absorption line variability

Chen Li, Jelle S. Kaastra, Liyi Gu, Missagh Mehdipour, Keigo Fukumura, Matteo Guainazzi, Misaki Mizumoto, Ehud Behar et al.

NGC 3783 exhibits a prominent Fe XXV absorption trough in the time-averaged XRISM/Resolve spectrum. To investigate its short-term variability, we present a time-resolved analysis of the Fe XXV absorption line during the continuous 10-day observation. We divided the resolved absorption profile into five fixed velocity intervals and measured their normalized equivalent widths in 19 time-resolved spectra. Three velocity intervals exhibit significant equivalent-width (EW) variability. Two velocity i…

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astro-ph.HEastro-ph.IM

Reconstruction of Interstellar Cosmic Ray Anisotropy via Heliospheric Propagation Modeling and SVD Inversion

Reilly Tom, Paolo Desiati, Juan Carlos Díaz-Vélez, Perri Zilberman

Ground-based experiments such as the IceCube Neutrino Observatory and the High-Altitude Water Cherenkov Gamma-Ray Observatory detect cosmic-ray anisotropy on Earth, but magnetic deflections within the heliosphere complicate interpretation. Understanding the original spatial distribution of cosmic rays in the interstellar medium requires modeling particle propagation across the heliospheric boundary. We constructed a simulated transport model that backtracks antiprotons from Earth to the interste…

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astro-ph.EP

On the Orbital Evolution of Giant Planet Pair Embedded in a Gaseous Disk. III. simultaneous gas accretion and the final mass ratio

Bixuan Zhao, Hui Zhang, Yinhao Wu, Ya-Ping Li

Recent exoplanet surveys reveal a systematic trend in the mass ratios of giant planet pairs ($> 30 M_\oplus$). Although the $M_{outer}/M_{inner}$ is broadly centered near unity, it exhibits a dependence on orbital separation. Compact pairs tend to have comparable masses, whereas widely separated pairs show outer-heavy configurations. To investigate the origin of this trend, we perform two-dimensional hydrodynamic simulations that couple gas accretion and orbital migration of two giant planet emb…

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astro-ph.SRastro-ph.EPastro-ph.IM

The EBLM project - XX. Absolute dynamical masses of five low-mass eclipsing binaries, and an evaluation of mass estimation methods

Adam T. Stevenson, Yasmin T. Davis, Daniel Sebastian, Amaury H. M. J. Triaud, Pierre F. L. Maxted, Alix V. Freckelton, Thomas A. Baycroft, Neda Heidari et al.

Eclipsing binaries consisting of a solar-type primary and an M dwarf secondary are key laboratories to study objects at the bottom of the main sequence. Fundamental parameters of such stars have a direct impact upon exoplanetary studies, as searches for temperate Earth-sized planets focus on M dwarf hosts. Eclipsing binaries are essential to measure these parameters. However for stellar masses $<$ 0.35 M$_\odot$ , few double-lined eclipsing systems are known. Thus, stellar evolution models and e…

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astro-ph.SRastro-ph.EP

The EBLM Project - XIX. The absence of radius inflation in a homogeneous analysis of 66 Northern low-mass eclipsing binaries

Yasmin T. Davis, Amaury H. M. J. Triaud, David V. Martin, Alix V. Freckelton, Jenni R. French, Adam T. Stevenson, Annelies Mortier, Karen Collins et al.

Precise and accurate measurements of host stars are crucial in the search for Earth-like exoplanets, and M-dwarfs are favourable targets in this quest. Low-mass eclipsing binaries offer unique opportunities to empirically determine stellar masses and radii for low-mass stars where stellar models may be systematically biased. We present results from the EBLM-North sample, the largest homogeneous study of low-mass eclipsing binaries with secondary characterisation yet, combining high-resolution an…

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astro-ph.HE

Two sides of the same spin: tracking optical and radio pulsations of SAX J1808.4-3658 from outburst to quiescence

C. Ballocco, A. Miraval Zanon, A. Papitto, M. Burgay, M. C. Baglio, C. Malacaria, F. Ambrosino, A. Possenti et al.

High-time-resolution optical and UV observations have revealed bright coherent pulsations from accreting millisecond pulsars, exceeding the luminosity expected from thermal emission from NS hotspots or X-ray reflection by the accretion disk. Characterizing optical pulsations over a wide range of accretion rates through coordinated multi-wavelength observations can shed light on their origin. We present a timing study of the AMSP SAX J1808.4-3658 during its 2022 outburst and quiescence, using opt…

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astro-ph.HE

Cell-based theoretical criteria on the onset and stability limit of thermonuclear detonation

Kazuya Iwata, Keiichi Maeda, Ken J. Shen

One of the key unresolved problems in thermonuclear explosions of white dwarfs (WDs), including type Ia supernovae, is the condition for ignition and propagation of thermonuclear flame. Given the limitation of hydrodynamic simulations in resolving the flame front involved in the explosion process, theoretical considerations for these criteria merit accurate prediction of the onset of deflagration and detonation (deflagration-to-detonation transition or direct initiation) and subsequent stable pr…

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astro-ph.GA

EMU detection of mysterious multiple component radio-continuum emission from nearby spiral Seyfert I type galaxy 'Sand-timer' (NGC 7213)

M. D. Filipović, Z. J. Smeaton, B. S. Koribalski, R. Kothes, A. Ahmad, R. Z. E. Alsaberi, C. Bordiu, A. C. Bradley et al.

We present an Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) radio-continuum detection of the nearby spiral Seyfert I type galaxy NGC 7213 which we nickname `Sand-timer' due to its morphological appearance. We find intriguing, peculiar emission extending from the central supermassive black hole (SMBH), which we refer to as galaxy hyperbubbles and/or active galactic nucleus (AGN) jets. Finally, we find two previously undetected kiloparsec-scale feature…

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astro-ph.GA

MUSE-DARK IV. Comparing Dark Matter Densities to Star Formation Histories in 375 intermediate-z galaxies

B. I. Ciocan, N. F. Bouché, J. Fensch, D. Krajnović, J. Freundlich, H. Desmond, A. Jeanneau, B. Famaey et al.

(Abridged) Baryonic feedback is expected to transform cuspy dark-matter (DM) haloes into cores, but direct observational links between inner DM slopes and galaxy star-formation histories (SFHs) remain limited. We investigate and quantify the connection between halo inner slopes and baryonic assembly histories in a large sample of intermediate-z galaxies. We analyse 375 galaxies at 0.1<z<1.43 spanning 7<log(Mstar/Msun)<11.2 using 3D forward modelling of MUSE kinematics and disk-halo decomposition…

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physics.chem-phastro-ph.GA

Extrapolating Collisional Rate Coefficients for Molecules of Astrophysical Interest Using Neural Networks

Yigit Ergen, Jérôme Loreau

State-to-state rate coefficients for inelastic molecular collisions are essential inputs for non-local thermodynamic equilibrium radiative transfer models, yet their computation using quantum scattering methods is prohibitive for large molecules and highly excited rotational states. We investigate the ability of artificial neural networks to extend existing datasets of collisional excitation rate coefficients without performing additional scattering calculations. A multilayer perceptron model wa…

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astro-ph.GA

Massive black holes in the first billion years with JWST

Hannah Übler

The James Webb Space Telescope has unlocked uncharted territory for the study of early black holes, enabling the detection of fainter and smaller black holes at larger cosmological distances than previously possible. Compared to nearby massive black holes, they are characterised by several unexpected attributes, such as their multi-wavelength properties or their relation to their host galaxies. These observational findings challenge our understanding of the past evolution of present-day supermas…

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