Solar and Stellar Astrophysics · Cross-listed from physics.space-ph
Direct Four-Spacecraft Measurement of Reconnection Exhaust Thickness in the Solar Wind
Mani K Chettri, Rupak Mukherjee and Hemam D. Singh
The thickness of a reconnecting solar wind current sheet is normally inferred from a single spacecraft as the product of the boundary-normal speed and the crossing duration. Multipoint measurements have tested this method for generic solar wind current sheets and constrained the geometry of reconnection exhausts, but a direct comparison with single-spacecraft thickness estimates for the same reconnection-associated crossings is still lacking. We analyze four current-sheet crossings observed by Magnetospheric Multiscale in the pristine solar wind on 2017 November 10 the two boundaries of a confirmed reconnection exhaust and two nearby current sheets. The tetrahedron separation was $\approx 16$ km. Cross-correlation of the
magnetic-field ramps gives millisecond-level lag uncertainties, boundary normals to $4^\circ-8^\circ$ and speeds to $5\%-8\%$, while single-threshold timing at these separations is noise dominated. The exhaust edges are 29-31 ion inertial lengths ($d_i$) thick. The two edge normals differ by $22^\circ$ (68% interval [$19^\circ,26^\circ$]), resolving a nonparallel exhaust geometry. At the exhaust edges, the measured boundary speeds agree with three standard single-spacecraft estimates to 4%-15% and remain within about one Alfvén speed of the
plasma motion. Estimating the normal from one spacecraft is the larger source of error, though the thickness is still recovered to within tens of percent when a degenerate minimum-variance solution is rejected. At the actively reconnecting sheet, the boundary speed exceeds the local
plasma speed along the normal by $29\% \pm 10\%$.
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Astrophysics of Galaxies
Same galaxy, different CGM: how the metal loading of galactic winds regulates the baryon cycle in Milky Way-mass galaxies
Prachi Khatri, Freeke van de Voort, Rebekka Bieri et al. (+5 more)
The circumgalactic medium (CGM) is both the reservoir of gas that fuels
star formation and
galaxy growth, and the repository for the mass, energy, and metals expelled through stellar
evolution and feedback. We present a controlled experiment using a suite of five cosmological magnetohydrodynamical simulations of a Milky Way-mass
halo from the Auriga suite, where we vary the metal content and energy loading of galactic winds driven by stellar feedback. We chose these parameters in combination such that all five runs obtain very similar (within $\approx$10%) $z=0$ stellar masses and morphologies and thus produce similar amounts of metals throughout their lifetimes. Our simulations differ substantially in where these metals end up, spatially within the
halo and across the different baryonic components (
stars, gas disc, CGM, and the intergalactic medium). The metal content affects the cooling efficiency of the
halo gas, regulating the CGM cool gas fraction and the
accretion rates onto the
galaxy. Between our two extreme models, we report an order of magnitude difference in the median gas
metallicity at vertical heights $|z| \gtrsim 30$ kpc above the disc plane. Current constraints on the
metallicity of the Milky Way
halo gas from absorption-line measurements of intermediate- and high-velocity clouds at $|z| \lesssim 15$ kpc are broadly consistent with our simulations, though a direct comparison is limited by differences in the adopted methods. Our findings show that
galaxies with nearly identical stellar content and morphology can differ substantially in their CGM, which offers a promising avenue for constraining feedback physics within
galaxy formation models.
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All authors Prachi Khatri, Freeke van de Voort, Rebekka Bieri, Rüdiger Pakmor, Robert J. J. Grand, Thomas A. Rintoul, Maria Werhahn, Rosie Y. Talbot
Cosmology and Nongalactic Astrophysics
Reassessing Evidence for Dark-Sector Interactions with Dynamical Dark Energy and DESI DR2
Jincheng Wang, Hongwei Yu and Puxun Wu
Recent baryon acoustic oscillation measurements from DESI Data Release 2, when combined with CMB and
supernova data, strengthen the motivation for exploring departures from $\Lambda$CDM in the late-time expansion history. Because an evolving dark-energy equation of state and an interaction within the dark sector can produce partially degenerate effects on the background expansion, their observational signatures should be assessed simultaneously. We first consider an interacting $w_0w_a$CDM model with $Q=\beta H\rho_{\rm de}$, using Planck and ACT CMB data, DESI DR2, and DES-Dovekie
supernovae. Allowing the dark-energy equation of state to evolve substantially weakens the preference for a nonzero coupling, while the preference for dynamical dark energy persists. The interaction provides essentially no additional improvement in the best fit, suggesting that part of the coupling preference found in more restricted interacting models may reflect a degeneracy with dark-energy dynamics. We then examine the same interaction for three one-parameter dynamical dark-energy trajectories: thawing, mirage, and generalized emergent dark energy (GEDE). The role of the interaction depends strongly on the assumed trajectory. The thawing and GEDE models favor sizable couplings of opposite signs, whereas the mirage trajectory already closely follows the dark-energy
evolution preferred by the data and provides little support for an additional interaction. These models also predict markedly different signatures in structure growth, ranging from enhanced matter clustering in the interacting thawing model to strong suppression in interacting GEDE. These contrasting growth signatures, despite substantial degeneracies at the background level, highlight late-time large-scale-structure observations as a promising avenue for distinguishing dark-energy dynamics from dark-sector interactions.
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Earth and Planetary Astrophysics
Low-energy ring particle accretion as the origin of Pan's equatorial ridge
Marco Baj, Iosto Fodde, Lucia Francesca Civati et al. (+1 more)
Pan is a small Saturnian satellite embedded within the
planet's A ring, characterized by a polygonal equatorial ridge whose formation mechanism remains debated. A proposed explanation is ring particle
accretion, yet previous simplified models could not address the ridge's complex multi-lobed morphology without ad hoc assumptions, and the cause of its latitudinal spread remains unclear. This work studies the complex low-energy dynamics around Pan to verify whether the ring particle
accretion paths are consistent with the observed ridge morphology. We model particle motion using a CR3BP with spherical harmonic perturbations.
Accretion paths are analyzed via grid-search simulations of trajectories transiting the $L_1$ and $L_2$ necks, using backward propagation from Pan's surface to determine the impacting material's original orbital characteristics. Asymmetric accreting particle populations, with inner-ring particles located closer to Pan and contributing more significantly to the impact flux, produce impact distributions that correlate with the ridge structure, especially for the Saturn-facing hemisphere. The ridge latitudinal spread is recovered only when the out-of-plane position and velocity of the accreting particles are strictly limited, consistent with
accretion from a thin disk such as Saturn's rings. Furthermore, analysis of the particles' impact conditions revises the previously estimated minimum
accretion duration downward by an order of magnitude, to $10^4$ yr, while accreting material is shown to originate from ring particles that once populated the Encke Gap. By systematically sampling admissible low-energy trajectories near Pan, our grid-search approach resolves the complex
accretion dynamics that previous simplified narrow-stream models do not capture, revealing that the ridge's main morphological features emerge naturally from the local low-energy dynamical environment.
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All authors Marco Baj, Iosto Fodde, Lucia Francesca Civati, Fabio Ferrari
High Energy Astrophysical Phenomena
Single-pulse reanalysis of the 2024 Vela glitch and new observations of PSR~J0437$-$4715 and PSR~J1644$-$4559
Carlos O. Lousto, Ruby Shrestha, Ezequiel Zubieta et al. (+6 more)
The
Pulsar Monitoring in Argentina (PuMA) collaboration systematically monitors southern glitching
pulsars, maintaining high-cadence single-pulse records of the Vela
pulsar. We present a pulse-per-pulse reanalysis of the 2024 major glitch of Vela (PSR~J0835$-$4510) with the 400~MHz-bandwidth ROACH backend of the Argentine Institute of Radioastronomy, and extend our machine-learning single-pulse pipeline—Isolation Forest outlier rejection, $\beta$-Variational-AutoEncoder denoising, and Self-Organizing-Map clustering—to new observations of PSR~J1644$-$4559 and the millisecond
pulsar PSR~J0437$-$4715. For Vela, the 4- and 6-cluster decompositions of the eight days bracketing the glitch reproduce, with seven times the previous bandwidth, the behavior found with the narrow-band ETTUS receivers: higher-amplitude clusters peak earlier in phase, are narrower, more skewed, and less populated. With the glitch jump and its two exponential recovery terms included in the timing solution, the mean profile is stable to 1% across all eight days (width change $-0.5\pm0.9$% from pre- to post-glitch); omitting the recovery terms would mimic a post-glitch broadening of up to 55% through a folding-frequency error at the $10^{-7}$ level. The clusters of PSR~J1644$-$4559 differ almost exclusively in amplitude, as expected for a scattering-dominated profile. For PSR~J0437$-$4715, retaining the 10% of pulses with the highest peak-dominance score doubles the signal-to-noise ratio, and a five-cluster decomposition yields narrow, phase-ordered groups a factor $3.6\pm0.4$ narrower than the average profile, suggesting a $\sim$3.5-fold improvement in cluster-based timing precision for this
pulsar-timing-array target, to be confirmed in a follow-up paper.
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All authors Carlos O. Lousto, Ruby Shrestha, Ezequiel Zubieta, Susana B. Araujo Furlan, Guillermo Gancio, Federico García, Santiago del Palacio, Ryan Missel, Linwei Wang
Cosmology and Nongalactic Astrophysics
Beyond isolated curvature peaks: collective collapse and multiple Primordial Black Hole formation
Albert Escrivà
Primordial black hole (PBH) calculations usually treat rare
curvature peaks as isolated collapsing regions. Using fully nonlinear $3+1$ numerical-relativity simulations in a radiation-dominated Universe, we demonstrate that neighbouring primordial
curvature perturbations need not map one-to-one onto PBHs: they may ultimately disperse, collapse collectively into a single PBH, or undergo distinct local collapses and form more than one PBH. In the family of two-component profiles studied here, the latter outcome is a pair of PBHs, identified by the coexistence of two disconnected apparent horizons on at least one time slice. We introduce a nonspherical quasi-local compaction diagnostic based on the Hawking mass and referenced to a round flat-FLRW sphere of equal area. It retains the angular structure of the
curvature field and reduces to the standard Misner-Sharp compaction function in spherical
symmetry. The global maximum of this diagnostic, $\mathcal K_{\rm form}$, provides an empirical indicator of whether at least one PBH forms, with a transition near $\mathcal K_{\rm form,c}\approx0.56$ and modest profile-dependent scatter. For forming bimodal profiles, we supplement the nonlinear compactness with a signed linear surface strength evaluated on the same probing spheres. The viability of the weaker local branch and the competition between the local and common-enclosing branches improve the empirical discrimination between single- and double-PBH outcomes. Our results therefore show that the maximum
curvature amplitude alone does not determine the collapse outcome, which also depends on the spatial extent, characteristic scales, and geometry of the surrounding
curvature environment.
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Earth and Planetary Astrophysics
New and Updated Rossiter-McLaughlin Measurements for Three Hot Jupiter-Hosting M Dwarfs
Drew Weisserman, Ryan Cloutier, Alexandra Rochon et al. (+12 more)
Evidence suggests that Kozai-Lidov high-eccentricity migration (HEM) is the dominant migration channel for short-period Giant
Exoplanets around M dwarf
Stars (GEMS). However, it is unlikely that all short-period GEMS form via HEM, given that most systems lack known massive companions capable of driving HEM. Characterizing the stellar obliquities of GEMS via the Rossiter-McLaughlin (RM) effect can help shed light on the dynamical histories of GEMS. We present RM effect detections for the GEMS TOI-5205 b, TIC 46432937 b, and TOI-3714 b using the Gemini-North/MAROON-X spectrograph, bringing the total number of GEMS with RM detections to five. Our systems are well-aligned, with sky-projected obliquities of $\lambda = 0 \pm 6^\circ$, $3_{-3}^{+4}$$^\circ$, and $15_{-8}^{+12}$$^\circ$, respectively, and we measure a deprojected obliquity of $\psi = 24_{-8}^{+7}$ $^\circ$ for TOI-3714. We analyze archival radial velocities, astrometry, and speckle imaging data to search for additional companions around all five known GEMS with RM detections. We find tentative evidence for a new massive companion around one of these GEMS, TOI-5293 A, in Gaia DR2+DR3 data, though further follow-up is needed for confirmation. We rule out massive companions between $\sim 1-10\textrm{ AU}$ in the remaining systems, but cannot rule out all companions capable of driving HEM. Our findings present further evidence that short-period GEMS are preferentially aligned. While current results remain consistent with both primordial
alignment and HEM plus tidal damping, we offer future directions for studies to further constrain the dominant migration channel for GEMS.
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All authors Drew Weisserman, Ryan Cloutier, Alexandra Rochon, Ze'ev Vladimir, Bertram Bitsch, Ritvik Basant, Jacob L. Bean, Tanya Das, Emily Deibert, Thomas M. Evans-Soma, Michael Line, Ralph Pudritz, Andreas Seifahrt, Evgenya L. Shkolnik, Luis Welbanks
Earth and Planetary Astrophysics
JWST MIRI reveals a potential atmosphere on the ultra-hot rocky planet TOI-431b
Cole Smith, Brandon Park Coy, Megan Weiner Mansfield et al. (+13 more)
An open question in
exoplanet science is whether rocky
exoplanets extremely close in to their host
stars, `lava worlds', can retain significant atmospheres. Thermal emission observations via secondary eclipse can be used to determine whether a rocky
exoplanet possesses an atmosphere. It is expected that an atmosphere could increase the
planet's albedo and/or redistribute heat away from the dayside, reducing the secondary eclipse depth measured. Recent eclipse observations of lava
planets, rocky
planets hot enough to have
liquid magma surfaces, have suggested the presence of atmospheres. Here, we present a single JWST MIRI/LRS partial secondary eclipse of the lava
planet TOI-431b. We measure an eclipse depth of 81 $\pm$ 16 ppm, which corresponds to a brightness temperature of $1967^{+237}_{-253}$ K and a brightness temperature ratio R = $0.81\pm0.10$, being 1.2 $\sigma$ higher than the value reported by Spitzer. The observed brightness temperature ratio is 1.8$\sigma$ below that of a zero-albedo, zero heat redistribution bare rock (R=1). Given that magma pools are expected to have low albedos, we find that our results are best explained by the presence of an atmosphere. Future work to measure the exact composition of TOI-431b's atmosphere and improve models of lava
planet atmospheres would better constrain the nature and
evolution of lava
planets.
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All authors Cole Smith, Brandon Park Coy, Megan Weiner Mansfield, Rafael Luque, Anjali A. A. Piette, Qiao Xue, Michael Zhang, Jacob L. Bean, Madison Brady, Peter Gao, Jegug Ih, Eliza M.-R. Kempton, Edwin Kite, Daniel Koll, Jaume Orell, Enric Palle
Instrumentation and Methods for Astrophysics
A fast, wide-field, and real-time imaging prototype for large aperture arrays
Nithyanandan Thyagarajan, Jishnu Thekkeppattu and David Humphrey
Real-time processing on sub-millisecond timescales is essential for detecting fast astrophysical transients such as fast
radio bursts (FRBs) and
prompt electromagnetic counterparts to gravitational-wave mergers. Immediate localisation enables rapid multi-wavelength follow-up and maximises scientific return. As a result, real-time capability has become a key requirement for modern wide-field aperture arrays, which are increasingly being deployed at scales of thousands to tens of thousands of
antenna elements. However, traditional correlator architectures scale as $\mathcal{O}(N^2)$, creating significant computational, bandwidth, and power challenges for large-$N$ arrays. These constraints often limit field of view, angular resolution, or observing duty cycle, ultimately reducing transient discovery potential. Direct imaging of the full field of view using E-field Parallel Imaging “Correlator” (EPIC) offers a promising alternative by avoiding the explicit formation of pairwise correlations. EPIC can achieve $\mathcal{O}(N \log N)$ computational scaling for dense aperture arrays and has been demonstrated on the Long Wavelength Array (LWA) station in Sevilleta (USA) using Graphics Processing Unit (GPU). However, GPU implementations can be limited by
memory bandwidth in low-bitwidth gridding and Fast
Fourier Transform (FFT) workloads. We, therefore, are developing a prototype implementation of EPIC using Field Programmable Gate Arrays (FPGA) that exploits highly parallel FFT pipelines to improve computational efficiency and reduce power consumption. Using preliminary results, we evaluate its performance particularly from the viewpoint of scalability, and discuss its suitability for next-generation instruments including SKA-Low and mid-frequency aperture arrays.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
DANSur_HM: Modularly incorporating higher modes in a deep learning based gravitational-wave surrogate
Osvaldo Gramaxo Freitas, Anastasios Theodoropoulos, Nino Villanueva et al. (+4 more)
Numerical relativity (NR) simulations provide the most faithful representation of the gravitational waves (GWs) emitted by binary black hole (BBH) systems during merger. In the context of GW astronomy, tasks such as parameter estimation can require vast numbers of waveform evaluations per second across the entire parameter space. Since performing full NR simulations for each evaluation is not computationally feasible, interpolating methods for existing NR waveforms, known as surrogate models, have been developed with marked success. In this paper, we build on our previous work to introduce methods to train a fast surrogate model based on neural networks in order to generate BBH merger waveforms, including the fundamental (2,2) mode, as well as the (3,3), (2,1), (4,4), (3,2), (4,3) and (5,5) higher-order modes. Applying a pretraining step on approximant data before fine-tuning on NR data allows us to smooth out the parameter space, and making use of the parallelization ability of GPUs to project the NR waveforms in the inclination-phase $(\iota, \phi)$ sphere during training allows the fitting of all the explored modes simultaneously. The developed surrogate model, DANSur\_HM, achieves average mismatches of the order of $10^{-4}$, with the worst mismatch at $2.5\times10^{-3}$, and achieves throughput above $6\times10^5$ waveforms/second on an NVIDIA V100 GPU. Parameter estimation tests confirm the usefulness of the inclusion of higher modes.
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All authors Osvaldo Gramaxo Freitas, Anastasios Theodoropoulos, Nino Villanueva, José A. Font, Antonio Onofre, Alejandro Torres-Forné, José D. Martin-Guerrero
Astrophysics of Galaxies
Evolution of bar-induced dark gaps in galaxy discs: evidence of strong bar-driven effects already at $z > 2$
Susnata Chattopadhyay, Soumavo Ghosh, Dimitri A. Gadotti et al. (+5 more)
The properties of stellar bars play a crucial role in determining the bar-driven secular
evolution in disc
galaxies. However, a systematic observational study of the
evolution of several bar properties (such as strength and length) across
cosmic time is largely missing. In this paper, using a sample of $625$ barred
galaxies, taken from SDSS, HST COSMOS, and JWST CEERS surveys, we systematically investigate the
evolution of bar properties over
redshifts ($0.02 \lesssim z < 3$) by making a novel usage of dark gap (preferential light deficit along the bar minor axis) properties as a proxy for bar properties. We show that the dark gap strength ($\Delta \mu_{\rm max}$) exhibits a weak
evolution, increasing from higher
redshifts ($z \sim 2.5$) and slightly declining towards lower
redshifts ($z < 0.05$). Conversely, the extent of dark gaps ($R_{\rm DG}, R_{\rm dark}$; normalised by bar length) decreases moderately from $z \geq 1.4$ and remains constant thereafter. Our results suggest that bar formation and the initial rapid growth phase occur before $z \sim 3$, followed by mild growth towards lower
redshifts. We also find $R_{\rm dark}$ to be a better proxy (as compared to $R_{\rm DG}$) for estimating bar length, supporting earlier theoretical studies. Furthermore, the $\Delta \mu_{\rm max}$ shows a weak but statistically significant correlation with bar-to-total light ratio (Bar/T) and bar ellipticity ($\epsilon_{\rm bar}$). Studies of the
redshift evolution of bar properties over such an extensive
redshift range as done here are instrumental in constraining the bar-driven
evolution at early
cosmic times.
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All authors Susnata Chattopadhyay, Soumavo Ghosh, Dimitri A. Gadotti, Zoe A. Le Conte, Taehyun Kim, Virginia Cuomo, Camila de Sá-Freitas, E. Athanassoula
High Energy Astrophysical Phenomena
Multi-epoch Detection of an Ultra-fast Inflow in ESP 39607: Evidence for an Accretion Cascade
Alessandro Peca, Michael J. Koss, Roberto Serafinelli et al. (+10 more)
We present simultaneous XRISM, XMM-Newton, and NuSTAR observations of ESP 39607, a Seyfert 2
galaxy at $z = 0.201$. XRISM/Resolve reveals two absorption features near 4.7 and 4.9 keV in the observed frame, consistent with redshifted Fe XXV He-$\alpha$/Fe XXVI Ly-$\alpha$ absorption from gas inflowing at $v_{\rm in} \simeq 0.16c$. The high velocity identifies the absorber as an ultra-fast inflow (UFI), which is detected at $\sim 3$-$3.7\sigma$ across different methods and continuum models. Photoionization modeling yields $\log \xi/{\rm erg\,s^{-1}\,cm} \simeq 3.7$-$3.8$ and a column density $\log N_{\rm H,abs}/{\rm cm^{-2}} \simeq 23.2$-$23.8$, the latter depending on the assumed
metallicity. The inflow velocity and line properties are consistent with those reported from two earlier NuSTAR epochs, indicating that similar inflowing material was present over a baseline of at least 2.2 yr in the source rest frame. Across all three epochs, the combined detection significance of the UFI is $5.3\sigma$. Given the dynamical timescale of a few days at the inferred radius, $R \simeq 49$-$77\,R_{\rm g}$, the multi-year evidence favors a scenario in which the inflow is continuously replenished, forming an
accretion "cascade", rather than a single long-lived cloud. With an estimated mass inflow rate of $\dot{M}_{\rm in} \simeq 0.3$-$1.4\,M_\odot$ yr$^{-1}$, depending on
metallicity, and a ratio $\dot{M}_{\rm in}/\dot{M}_{\rm acc} \simeq 0.2$-$1.0$, the inflow could supply a substantial fraction of the
accretion needed to power the central active galactic
nucleus.
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All authors Alessandro Peca, Michael J. Koss, Roberto Serafinelli, C. Megan Urry, Claudio Ricci, Keigo Fukumura, Massimo Gaspari, Elias Kammoun, Alessia Tortosa, Giulia Cerini, Peter G. Boorman, Richard Mushotzky, Quirino D'Amato
Solar and Stellar Astrophysics
The scarcity of white dwarf-brown dwarf binaries in the solar neighbourhood: A population synthesis study
Alejandro Santos-García, Santiago Torres, Alberto Rebassa-Mansergas et al. (+3 more)
White dwarf–brown dwarf (WD–BD) binaries are intrinsically rare systems that provide a unique opportunity to study binary
evolution and the formation of substellar companions. Despite recent observational progress, only a small number are known in the solar neighbourhood. We investigate whether their scarcity can be explained by binary formation and
evolution together with observational selection effects. We extend the MRBIN binary population synthesis code into the substellar regime by incorporating brown dwarf evolutionary models and an extended initial mass function. We simulate the stellar population within 100 pc of the Sun and compare the predicted WD–BD population with the observed sample. Our simulations predict 13+-5 WD–BD systems within 100 pc, consistent with observations. These systems represent only 0.1% of the local white dwarf population, confirming their rarity. The models reproduce the overall distributions of white dwarf masses, temperatures, and orbital periods, although the simulated brown dwarfs are systematically hotter than observed. Close WD–BD binaries are underproduced with the standard common-envelope efficiency 0.3, suggesting that higher efficiencies may be required to reproduce the observed short-period systems. The simulations also reproduce the observed deficit of systems at intermediate orbital periods between post-common-envelope binaries and wide non-interacting systems, as well as a weakened brown dwarf desert in main-sequence–brown dwarf binaries.
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All authors Alejandro Santos-García, Santiago Torres, Alberto Rebassa-Mansergas, Sarah L. Casewell, Zhangliang Chen, Hongwei Ge
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Strong Constraints on Line Signals from Dark Matter Annihilation in a Nearby Subhalo
Asier Salces Pérez, Thong T.Q. Nguyen, Pedro De la Torre Luque et al. (+1 more)
We present a dedicated search for monochromatic gamma-ray emission from a recently proposed nearby dark matter subhalo candidate. Using nearly 15 years of Fermi-LAT Pass 8 data, we perform a sliding-window search for gamma-ray lines between 10 and 300 GeV. We do not find any statistically significant evidence for a line signal. The largest excess occurs at $E_\gamma \simeq 28 \, {\rm GeV}$ with a local significance of $2.5\sigma$. We therefore derive 95% confidence level upper limits on the annihilation cross section for $\chi\chi \rightarrow \gamma\gamma$. Under the assumed NFW subhalo model, the resulting constraints are stronger than existing Galactic Center line limits over much of the explored mass range. We further translate these line constraints into bounds on well-motivated WIMP models, such as
Higgs-portal and Wino dark matter scenarios, restricting previously open parameter regions consistent with thermal freeze-out as well as models associated with dark matter interpretations of the Galactic Center Excess.
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All authors Asier Salces Pérez, Thong T.Q. Nguyen, Pedro De la Torre Luque, Tim Linden
Astrophysics of Galaxies
Classical Cepheids in the Nuclear Stellar Disk: membership via dynamical analysis
M. De Leo, M. Zoccali, R. Albarracin et al. (+2 more)
(abridged) Four classical Cepheids have been associated to the Nuclear Stellar Disk (NSD), suggesting a burst of
star formation 20 Myrs ago. In this work, we analyse all available data for these four Cepheids in order to gauge if they are bona fide members of the NSD or interlopers in the region. This allows to confirm or rule out the
star formation burst hypothesised in the literature. Our dynamical analysis is based on an updated MWpotential that includes all components of the inner
Galaxy. We conduct a thorough study of possible systematics, taking into account both observational errors and model dependencies. Our results suggest that only one Cepheid likely belongs to the NSD, while the orbits of other two extend well beyond it. Accounting for observational uncertainties, only 23-28 percent of the realisations sourced from the error distributions for the latter two are compatible with the NSD. For the fourth there are no proper motion measurements available and the light curve analysis puts into question its classification as a classical Cepheid. Through a comprehensive dynamical analysis of available data on the Cepheids attributed to the NSD, we gauged their membership to this structure. Out of the three Cepheids analysed in unprecedented depth, GCC-a is likely a member of the NSD while both GCC-b and GCC-c do not seem dynamically linked to it. Factoring in the observational uncertainties, a non-negligible percentage of the realisations for GCC-b and GCC-c are still compatible with the NSD, thus membership cannot be completely excluded for either with current data. The robust association of only one Cepheid casts doubt on the occurrence of a
star formation episode in the NSD, about 20 Myrs ago.
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All authors M. De Leo, M. Zoccali, R. Albarracin, B. Acosta-Tripailao, J. Minniti
Cosmology and Nongalactic Astrophysics
Universal CMB Phase Coherence from Single-Field Inflation
Siméon Vareilles, Thomas Colas, Julien Grain et al. (+2 more)
The phase coherence of primordial perturbations shapes the acoustic peaks of the CMB and is regarded as a key signature of inflation. Inflationary scenarios at different energy scales, thus with different durations, are commonly expected to leave different levels of coherence. We show this expectation fails: because the
curvature perturbation is conserved on super-Hubble scales, the coherence at recombination inherits a value fixed by the observed primordial spectrum alone. This holds irrespective of the inflationary energy scale and the subsequent expansion history.
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All authors Siméon Vareilles, Thomas Colas, Julien Grain, Federico Piazza, Vincent Vennin
High Energy Astrophysical Phenomena
Unlocking the QPE Mystery: Star-Disk Collisions in Realistic AGN Disks
Zhaohuan Zhu, Xiaoshan Huang, Yan-Fei Jiang et al. (+1 more)
Quasi-periodic eruptions (QPEs) are luminous, recurring soft X-ray outbursts observed in the
nuclei of low-mass
galaxies. They display two remarkable trends: outburst durations are $\sim$10-20% of the recurrence timescale, and longer bursts are more luminous. A promising theory that naturally explains the quasi-periodicity invokes collisions between a
star on an extreme mass-ratio inspiral (EMRI) orbit and the
accretion disk around the supermassive black hole. However, it remains unclear how this model reproduces the observed trends. We therefore carry out two-dimensional, multi-frequency radiation hydrodynamic (RH) simulations of
star–disk collisions. Crucially, we adopt a more realistic circumnuclear disk structure from previous Radiation MHD simulations of sub-Eddington
accretion disks. We find that the thick, puffed-up disk atmosphere, extending to $z/r\sim1$, causes different portions of the bow shock to break out at different times, producing prolonged thermal emission as the shock emerges through the breakout surface at $z/r\sim0.7$. The X-ray
flare duration is set by the shock propagation time through the optically thick disk–a $\sim$10% of the orbital timescale, reproducing the observed duty cycle. A more oblique
star-disk interaction yields a longer, more luminous
flare. The realistic AGN disk models also exhibit a surface density $\Sigma\propto r^2$, giving a collisional energy $E\propto P^{2/3}$ that may explain the luminosity–period trend, especially for the weaker QPEs. Overall, we suggest that a more realistic circumnuclear disk structure can explain several observed QPE trends-and QPEs may, in turn, constrain the disk structure.
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All authors Zhaohuan Zhu, Xiaoshan Huang, Yan-Fei Jiang, Shunquan Huang
Astrophysics of Galaxies
Bridging integrated-light and resolved-star studies of Local Group dwarf spheroidals. A novel use of deep imaging based on amateur telescopes
Sergio Guerra Arencibia, Ignacio Trujillo, Mireia Montes et al. (+4 more)
Low-mass
galaxies beyond the Local Group can only be studied through their integrated light, yet it remains unclear whether structural parameters inferred from integrated light are directly comparable to those obtained from resolved-
star studies. Using new deep imaging obtained with small-aperture amateur
telescopes, we analyse the classical dwarf spheroidals Leo II, Sculptor, and Fornax, whose stellar distributions have been extensively characterised through resolved-
star studies. We find that the radial light distributions and effective radii inferred from integrated light are in excellent agreement with those derived from resolved
stars, showing that resolved-
star and integrated-light analyses can be placed within a common observational framework applicable across a broad range of distances. The two approaches are highly complementary: resolved-
star analyses trace
galaxies to very large radii but are limited by stellar crowding in their central regions, whereas integrated-light observations are insensitive to crowding and allow the inner stellar distribution to be traced to substantially smaller radii. The integrated-light analysis extends the structural analysis to radii up to an order of magnitude smaller than previous
star-counting studies while significantly reducing the scatter in the measured profiles.
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All authors Sergio Guerra Arencibia, Ignacio Trujillo, Mireia Montes, Ignacio Ruiz Cejudo, Carlos Marrero-de la Rosa, Vicente Fontana, Aleix Roig
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
Gravitational Backreaction in de Sitter: A Canonical ADM Approach
Giordano Cintia
We develop a canonical ADM framework for gravitational backreaction during inflation. Our approach extends the formalism used to compute cosmological correlators by applying it to the
evolution of the
quantum background, which we identify with the metric one-point function. The aim is to assess the
quantum stability of inflationary geometries under gravitational backreaction. Within this framework, the backreaction is determined by the expectation values of the
Hamiltonian constraint and the equations of motion for the spatial metric. Working in the exact de Sitter limit, we apply the framework to a massless minimally coupled spectator scalar field and the physical graviton polarizations. At one loop, their backreaction renormalizes the relation between the cosmological constant and the Hubble parameter without inducing any secular departure from de Sitter
evolution, in agreement with previous results. We perform the calculation using a hard momentum cutoff and show that a fixed physical cutoff allows the homogeneous background equations to be renormalized with time- and background-independent coefficients, in contrast to a fixed comoving cutoff. Finally, we demonstrate that the explicit representation of the backreaction depends on the gauge condition imposed on the metric fluctuations, as well as on the background-fluctuation split. Nevertheless, these different representations are related by a gauge transformation and are therefore physically equivalent.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Tidally-enhanced resonances in extreme-mass-ratio inspirals: A tertiary path to chaos
Kyriakos Destounis, Takuya Katagiri, Sajal Mukherjee et al. (+1 more)
Extreme-mass-ratio inspirals (EMRIs) provide a unique laboratory for probing strong-field
gravity and complex relativistic dynamics. We study a tidally deformed EMRI composed of a stellar-mass secondary orbiting a supermassive (non-)rotating black hole embedded in an external, adiabatically varying tidal environment. These systems provide a restricted, yet astrophysically motivated, realization of the relativistic three-body problem, expected to appear in active galactic
nuclei, with a clear hierarchy of masses and radiation-reaction timescales. The external tidal deformation breaks the axisymmetry of the Kerr spacetime, rendering the geodesic dynamics non-integrable and giving rise to chaotic motion. The resulting signature of non-integrability is characterized through Poincaré maps and rotation curves constructed from the ratios of the fundamental frequencies of bound radial, polar, and azimuthal motion. We identify two prominent plateaus whose widths increase with the tidal field amplitude, signaling a transition from weak to strong chaos. We then demonstrate the sensitivity of the chaotic dynamics to the orientation of the orbit relative to the tidal field. We further analyze the proper-time
evolution of the action-angle variables, showing that the angle combinations associated with the dominant commensurabilities are phase locked, thereby allowing the associated tidal contributions to induce secular changes in the constants of motion, whereas off-plateau angle combinations circulate. These results clarify the dynamical significance of the prominent plateaus and provide a novel phase-space characterization of tidal resonances in EMRIs. Finally, we discuss the potential role of radiation-reaction effects in driving EMRIs through tidal island crossings and the implications for gravitational-wave inference with future detectors.
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All authors Kyriakos Destounis, Takuya Katagiri, Sajal Mukherjee, Kostas D. Kokkotas
Earth and Planetary Astrophysics
Radial velocity detection of the TRAPPIST-1 planetary system with SPIRou and NIRPS
Alexandrine L'Heureux, René Doyon, Charles Cadieux et al. (+57 more)
The TRAPPIST-1 system is well-known for its seven transiting Earth-sized
exoplanets. It has been extensively studied and characterized, notably with transit timing variations (TTVs) to precisely measure the mass of the
planets. Using near-infrared spectroscopic observations obtained as part of the SPIRou Legacy Survey and the NIRPS Guaranteed Time Observation programs, we aimed to verify those values through radial velocity (RV) measurements of the system. Our RV analysis reveals that the current data do not have the precision required to individually detect the TRAPPIST-1
planets. However, we confidently detect ($\Delta\ln\mathcal{Z}=7.53$, 1860:1 odds) the combined RV signature of the
planets by informing their relative masses on the TTV analysis, with TRAPPIST-1 b as a proxy of the whole system. For the first time, the RV signal of the TRAPPIST-1 system is recovered: we find a RV semi-amplitude of $K_b=3.65^{+0.78}_{-0.83}$ m s$^{-1}$ corresponding to a planetary mass of $M_{p,\,b}=1.31\pm0.29$ M$_\oplus$, demonstrating that the RV measurements are consistent with the TTV model ($M_{p,\,b;\,\text{TTV}}=1.374\pm0.069$ M$_\oplus$). Additionally, the NIRPS RVs constrain the presence of giant
planets beyond the snow line, excluding Saturn-mass
planets out to 2.7-yr orbits and Neptune-mass objects out to 20 d. Through RV, we determined the stellar activity period to be of $3.22^{+0.22}_{-0.20}$ d. Its agreement with photometric measurements (K2 and TESS) confirms stellar rotation as the origin of the $\sim3.3$-d periodicity observed for TRAPPIST-1. We further investigated stellar activity with SPIRou polarimetric measurements, placing an upper limit on the longitudinal field ($|B_l|<40$ G, $3\sigma$). This limit is compatible with a weak multipolar large-scale
magnetic geometry, as observed in some of the later-type rapidly rotating M dwarfs.
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All authors Alexandrine L'Heureux, René Doyon, Charles Cadieux, Pascal Petit, Olivia Lim, Étienne Artigau, Neil J. Cook, Eric Agol, Xavier Bonfils, Julien Morin, Stefano Bellotti, Claire Moutou, Leslie Moranta, Jean-François Donati, Luc Arnold, Xavier Delfosse, Guillaume Hébrard, Romain Allart, François Bouchy, Lucile Mignon, Izan de Castro Leão, Dany Mounzer, Khaled Al Moulla, Frédérique Baron, Björn Benneke, Mathis Bouffard, Casey Brinkman, Bruno L. Canto Martins, Andres Carmona, Ryan Cloutier, Marion Cointepas, Nicolas B. Cowan, Eduardo Cristo, Roseane de Lima Gomes, Jose Renan De Medeiros, Xavier Dumusque, Dasaev O. Fontinele, Thierry Forveille, Yolanda G. C. Frensch, Jonathan Gagné, Jonay I. González Hernández, Nicole Gromek, Melissa J. Hobson, Vigneshwaran Krishnamurthy, Pierrot Lamontagne, Lison Malo, Eder Martioli, Yuri S. Messias, Louise D. Nielsen, Ares Osborn, Léna Parc, Caroline Piaulet-Ghorayeb, Nuno C. Santos, Bennett Neil Skinner, Avidaan Srivastava, Atanas K. Stefanov, Alejandro Suárez Mascareño, Gregg Wade, Joost P. Wardenier, Drew Weisserman
Solar and Stellar Astrophysics
Benchmarking Machine Learning Emulators of Stellar Evolution for Precision Asteroseismology
Naomi Gluck, Earl P. Bellinger, Yan Liang et al. (+5 more)
Fast and accurate stellar
evolution emulators—surrogate models that approximate expensive simulation outputs with machine learning (ML)—are powerful tools for modern stellar characterization, hierarchical inference, and population synthesis. We analyze the grid density required for reliable emulation by training ML
algorithms on main-sequence models with masses M=[0.7,1.2] solar masses. This range is challenging to emulate due to rapidly varying evolutionary behavior caused by the radiative-to-convective core transition, as well as the requirement to match the part-per-thousand seismic precision that has been delivered for such
stars from the NASA Kepler mission. Generating grids from analytical models, as well as MESA, YREC, MIST, and ASTEC, we compare linear interpolation, k-nearest neighbors, random forests, and neural networks (NNs) in interpolating the stellar observables: T_eff, L, Delta nu, and nu_max. While NNs outperform other methods, sparse grids induce localized failures in the core-transition region, resulting in unstable derivatives, ensemble disagreement, and fragmented posterior distributions during inference. Performance gains from denser grids are non-uniform, suggesting that adaptive grid generation should be favored over uniform refinement. Finally, we show that NN ensembles allow for localized uncertainty propagation, more accurately reflecting emulator reliability across parameter space than global uncertainty estimates. As we consider only the two-dimensional case of varying only stellar mass and age along the main sequence, these results represent a lower bound on the challenge in emulating stellar
evolution simulations for precision asteroseismology.
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All authors Naomi Gluck, Earl P. Bellinger, Yan Liang, Ebraheem Farag, Nicholas Saunders, Selim Kalici, Christopher J. Lindsay, Sarbani Basu
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Sub-TeV Singlino Dark Matter in light from Sagittarius A$^\ast$ and LUX-ZEPLIN Nuclear-Recoil Event
Utpal Chattopadhyay, Debottam Das, Rahul Puri et al. (+1 more)
We investigate the impact of a dark matter density spike surrounding the Milky Way's supermassive black hole (SMBH) on the detectability of Singlino-dominated neutralino dark matter within the Next-to-Minimal Supersymmetric Standard Model (NMSSM). Similar density enhancements, or mini-spikes, around stellar-mass black holes (sBHs), have also been considered. Such a dark matter (DM) candidate typically produces weak indirect detection signals in conventional dark matter
halos. Additionally, a Singlino-like lightest supersymmetric particle (LSP) is very difficult to probe at the LHC or through direct DM searches. Furthermore, a Singlino-like LSP with an almost degenerate Higgsino NLSP can produce an observable inelastic DD signal and is compatible with the anomalous high-recoil event recently reported by the LZ collaboration. Keeping these in consideration, we examine the prospects for detecting these sub-TeV dark matter scenarios through gamma-ray observations of the regions surrounding the SMBH Sgr A$^\ast$ and the sBH in the low-mass X-ray binary XTE J1118+480.
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All authors Utpal Chattopadhyay, Debottam Das, Rahul Puri, Joydeep Roy
Instrumentation and Methods for Astrophysics
The Impact of Artificial Space Objects on Optical Astronomy as Determined from 32 Million Photometric Observations
Anthony Mallama, Sergey Karpov and Richard E. Cole
Photometric observations of satellites, rockets and space debris brighter than magnitudes 6.0, 7.0 and 8.0 are characterized. Those magnitudes pertain to different levels of interference with astronomy as defined by the International Astronomical Union. The densities of objects per square degree of sky and brighter than the magnitudes listed above are 0.38 e-3, 0.76 e-3 and 1.10 e-3, respectively. Probabilities of objects appearing on astronomical images depend on the field of view and the exposure duration. For objects brighter than magnitude 7.0 the probability that one will appear on a 10 second exposure of a 10 degree square field of view is 15%. The probability that an object is visible to the unaided eye under dark sky conditions is 59%. These percentages represent all nighttime hours. We discuss how they change with the Sun's distance below the horizon. Examination of data for objects launched since the start of the spacecraft constellation era shows that satellites account for most of the bright observations. If the plans of satellite operators to launch a million spacecraft are realized, nearly every astronomical image of a few seconds duration and several degrees in size may be contaminated during several hours of each night. Finally, people viewing the night sky may perceive satellites more strongly than
stars.
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Earth and Planetary Astrophysics
POSEIDON III: The Aligned Orbit of the Hot Neptune Around the Hot Star WASP-195
Juan I. Espinoza-Retamal, Joshua N. Winn, Rafael Brahm et al. (+33 more)
Stellar obliquities provide important clues as to the formation and migration histories of planetary systems, but measurements remain scarce for Neptune-mass
planets, especially those orbiting hot
stars (above the Kraft break). Here we present observations of the Rossiter-McLaughlin effect in the hot-
star/hot-Neptune system WASP-195 ($T_{\rm eff}=6470\pm100$ K, $v\sin{i_\star}=10.5\pm1.1$ km s$^{-1}$) obtained with the Keck
Planet Finder and NEID spectrographs. A joint analysis of these observations, archival photometry, and archival radial velocities yields a sky-projected stellar obliquity of $\lambda=-10\pm7^\circ$, consistent with
spin-orbit
alignment. This makes WASP-195 one of the few hot-
star/hot-Neptune systems with a measured obliquity. Archival radial velocities from SOPHIE exclude Jupiter-mass
planets within approximately 3 au at $5\sigma$ confidence. The aligned and nearly circular orbit is naturally consistent with a history of disk-driven migration, although coplanar high-eccentricity migration or Roche-lobe overflow cannot be ruled out. We also investigate why so few Neptunes around hot
stars have measured obliquities. Their scarcity likely reflects a combination of the lower intrinsic occurrence of short-period Neptunes around hot
stars and the difficulty of confirming
planet candidates in this regime, where rapid stellar rotation broadens spectral lines and hampers conventional radial-velocity confirmation. Rapid rotation also increases the detectability of the Rossiter-McLaughlin effect, a feature that could help to widen the
planet confirmation bottleneck while expanding the obliquity census of small
planets around hot
stars.
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All authors Juan I. Espinoza-Retamal, Joshua N. Winn, Rafael Brahm, Luke B. Handley, Elise Koo, Caleb Lammers, Cristobal Petrovich, Gu{\dh}mundur Stefánsson, Andrés Jordán, Xian-Yu Wang, Songhu Wang, Nicholas Saunders, Erik A. Petigura, Lauren M. Weiss, Ashley D. Baker, Theron W. Carmichael, Fei Dai, Jerry Edelstein, Jack Foley, Benjamin J. Fulton, Steven Giacalone, Steven R. Gibson, Samuel Halverson, Andrew W. Howard, Howard Isaacson, Emma McIntyre, Pranav H. Premnath, Maleah Rhem, Kodi Rider, Ryan A. Rubenzahl, Arpita Roy, Christopher Smith, Judah Van Zandt, Josh Walawender, Elina Y. Zhang, Jingyi Zhang
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess
Kimiko Yamashita
We show that a dark-
photon dark matter framework can simultaneously account for two recently reported anomalies: the
halo-like Galactic gamma-ray excess identified by Totani in 15 years of Fermi-LAT data, and the $E_{\rm nr}=248\pm23\,({\rm stat})\pm23\,({\rm sys})$ keV nuclear-recoil event of interest reported by the LUX-ZEPLIN Collaboration. The dark matter is a $U(1)_X$ dark
photon $X$ with mass $m_X=420$ GeV, stabilized by a dark parity that forbids kinetic mixing with the Standard Model
photon. A light scalar mediator $\phi$, required to explain the Totani excess via Sommerfeld enhancement, is joined by a second light scalar $\phi'$ that couples a nearly degenerate heavier vector partner $V$ to $X$. The resulting inelastic transition $X+N\to V+N$, with mass splitting $\delta\simeq316$ keV close to the kinematic endpoint for $m_X=420$ GeV, naturally reproduces the localized LZ event once the detector energy resolution is included, while leaving the relic abundance and the
halo phenomenology of the original Totani-motivated
benchmark essentially unchanged.
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High Energy Astrophysical Phenomena
Magnetized accretion onto rapidly spinning binary black holes: mini-disk thermodynamics, magnetic transport, and dual jets
Luciano Combi, Manuela Campanelli, Sean M. Ressler et al. (+2 more)
Supermassive binary black holes embedded in gas-rich environments are promising multi-messenger sources for
pulsar timing arrays and future space-borne gravitational-wave interferometers. Their electromagnetic emission is governed by nonlinear
plasma dynamics around the binary and is expected to inherit variability associated with the orbital motion thereof. Because active galactic
nuclei are intrinsically
stochastic, identifying robust binary signatures requires predictive models that connect large-scale circumbinary flows to the black holes. Previous relativistic simulations of accreting binaries have mostly focused on smaller separations and lower
spins. We perform three-dimensional general relativistic magnetohydrodynamic simulations of a relaxed, magnetized circumbinary disk accreting onto an equal-mass binary black hole with a separation of $30$ gravitational radii and dimensionless
spin $\chi=0.9$. At these separations, the mini-disks around each black hole are persistent mass reservoirs but still show pronounced amplitude modulations governed by the eccentric circumbinary disk and the sloshing gas between the mini-disks. We analyze how the
magnetic flux is transported from the circumbinary disk to the horizons, launching powerful dual jets with energy extraction efficiencies reaching $\approx 40\%$. The horizon-threading flux and jet luminosity alternate between the two black holes, producing an on-off dual-jet state. The wide jet funnels interact above the binary and form a persistent current sheet favorable to reconnection. We explore the influence of mini-disk thermodynamics, comparing efficient and inefficient cooling inside the cavity. Hotter mini-disks are less massive, exhibit weaker coherent periodicity, and launch less luminous jets despite comparable horizon-threading
magnetic flux.
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All authors Luciano Combi, Manuela Campanelli, Sean M. Ressler, Alexander J. Dittmann, Federico Cattorini
High Energy Astrophysical Phenomena
Vortex pinning and the elastic response of neutron-star crusts II. Non-axisymmetric loading and Magnus mountains
Elia Giliberti
Pinned superfluid
vortices transmit a Magnus force to the
neutron-
star crust. A non-axisymmetric component of the superfluid-
lattice lag can therefore support a persistent mass quadrupole. We calculate the l=m=2 response of self-gravitating, radially stratified spherical
stars with SLy4 and BSk21 backgrounds, using a local microscopic pinning cap and a density-dependent Coulomb-
lattice shear modulus. For a 1.4 M_sun
star at 100 Hz, the
equilibrium-compression maxima are epsilon=2.67x10^-9 (SLy4) and 2.44x10^-9 (BSk21). The global quadrupole is strikingly insensitive to the shear prescription: replacing mu=0.01P by the Coulomb profile and strongly varying uncertain edge layers changes the result only at the percent level. The dominant internal sensitivity is instead compressional. A density-resolved compressional kernel increases through the inner crust and steepens close to the crust-core interface, particularly for BSk21, showing that the deep inner crust controls the EoS dependence of the mountain. A fixed-composition calculation is used only as a non-relaxed sensitivity diagnostic, not as the secular prediction. At a common true local velocity
benchmark, our fiducial ellipticities remain more than an order of magnitude below the complementary two-component cylindrical calculation of Gangwar & Jones (2026). We argue that the comparison points to the relative superfluid-
lattice degree of freedom as the natural next ingredient for a common spherical model. The main result is therefore physical rather than numerical: the Magnus-mountain scale is robust to shear microphysics, while the deep-crust compressional response sets the leading uncertainty of the one-displacement model.
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Instrumentation and Methods for Astrophysics
High performance Stingray
Eleonora Veronica Lai, Matteo Bachetti, Maura Pilia et al. (+4 more)
X-ray astrophysical objects show variability on a wide range of timescales, i.e. from fractions of second to years. The open-source Python library stingray is able to perform time series analyses with a focus on high-energy astrophysics. Comprising the most commonly used
Fourier analyses techniques, it also supports a range of additional extensions able to analyse
pulsar data, simulate data sets and perform statistical modelling. With the latest release of the code, new
Fourier methods and support for additional missions have been implemented, making Stingray more easily adaptable and extendable to other use cases. In this paper we focus on testing the performance and robustness of the latest version of stingray . We consider the possible different behaviour of the code when dealing with data sets smaller or larger than the RAM. We address the problem of dealing with large data sets and implemented parallel versions of the slowest methods in this regime. For small data sets, we investigate the possibility of a porting in GPU of key functions of the code.
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All authors Eleonora Veronica Lai, Matteo Bachetti, Maura Pilia, Daniela Huppenkothen, Matteo Lucchini, Guglielmo Mastroserio, Hamza El Byad
Earth and Planetary Astrophysics
The Ultraviolet Spectrograph on ESA's Jupiter Icy Moons Explorer Mission (JUICE-UVS)
Kurt D. Retherford, Philippa M. Molyneux, Thomas K. Greathouse et al. (+51 more)
The Jupiter Icy Moons Explorer (JUICE) mission, led by ESA, has an Ultraviolet Spectrograph (JUICE-UVS) contributed by NASA and built at Southwest Research Institute. JUICE-UVS is designed to provide a diversity of measurements to further our understanding of the potential habitability of icy ocean worlds at Jupiter and to study Jupiter and the Jovian system as an archetype for gas giants. JUICE-UVS observes
photons in the 50-204 nm wavelength range at moderate spectral and spatial resolution along a 7.5 deg slit composed of 7.3 deg x 0.1 deg and 0.2 deg x 0.2 deg contiguous sections. JUICE-UVS performs a comprehensive study of icy satellite atmospheres, plumes, surfaces, and local space environments; Jupiter's atmosphere and aurora; Io and its Io
Plasma Torus; and other Jupiter system targets (rings, small moons, etc.) as available. The variety of observational techniques employed include: nadir push-broom imaging, disk scans, limb stares, stellar and solar occultations, Jupiter transit observations, and neutral cloud/
plasma torus stares and scans. This paper describes the UVS investigation's science plans, instrument details, concept of operations, and data formats in the context of the JUICE mission's habitability and Jupiter system goals.
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All authors Kurt D. Retherford, Philippa M. Molyneux, Thomas K. Greathouse, Michael W. Davis, G. Randall Gladstone, Steven C. Persyn, Maarten H. Versteeg, Mary F. Araujo, Fran Bagenal, Tracy M. Becker, Arnaud Beth, Ronald K. Black, Bertrand Bonfond, Shawn M. Brooks, Emma J. Bunce, Alain Carapelle, Steven Cortinas, Gregory J. Dirks, Bryan Esquivel, Paul D. Feldman, Sue Ferrell, Mark Ferris, Leigh N. Fletcher, Matthew A. Freeman, Marina Galand, Rohini S. Giles, Denis Grodent, Vincent Hue, Erica Johnson, Joshua A. Kammer, Cynthia Kempe, Laurent Lamy, Adrian Martin, Melissa A. McGrath, Edward G. Nerney, Carlos Nuñez, Zachary Olsen, Norman Pelletier, Brandon Perez, Kristian B. Persson, Eric Quémerais, Rick Raffanti, Ujjwal Raut, Ryan Rickerson, Lorenz Roth, Oswald H. W. Siegmund, John R. Spencer, Andrew J. Steffl, Bradley J. Trantham, John V. Vallerga, Todd J. Veach, Michael A. Velez, Brandon C. Walther, the JUICE-UVS Team