Alexander Venner, Andrew Vanderburg, Chelsea X. Huang
et al.
The transit method is currently one of our best means for the detection of potentially habitable “Earth-like” exoplanets. In principle, given sufficiently high photometric precision, cool Earth-sized exoplanets orbiting Sun-like stars could be discovered via single transit detections; however, this has not previously been achieved. In this work, we report a 10 hr long single transit event which occurred on the V = 10.1 K-dwarf HD 137010 during K2 Campaign 15 in 2017. This transit is comparatively shallow (225 ± 10 ppm) but is detected at high signal-to-noise thanks to the exceptionally high photometric precision achieved for the target. Our analysis of the K2 photometry, historical and new imaging observations, and archival radial velocities and astrometry strongly indicate that the event was astrophysical, occurred on-target, and can be best explained by a transiting planet candidate, which we designate HD 137010 b. The single observed transit implies a radius of $1.0{6}_{-0.05}^{+0.06}\,{R}_{\oplus }$ , and assuming negligible orbital eccentricity we estimate an orbital period of $35{5}_{-59}^{+200}$ days ( $a=0.8{8}_{-0.10}^{+0.32}$ au), properties comparable to Earth. We project an incident flux of $0.2{9}_{-0.13}^{+0.11}\,{I}_{\oplus }$ , which would place HD 137010 b near the outer edge of the habitable zone. This is the first planet candidate with Earth-like radius and orbital properties transiting a Sun-like star bright enough for substantial follow-up observations.
Ankan Sur, Adam Burrows, Roberto Tejada Arevalo
et al.
Computed using the APPLE planetary evolution code, we present updated evolutionary models for Jupiter and Saturn that incorporate helium rain, nonadiabatic thermal structures, and “fuzzy” extended heavy-element cores. Building on our previous Ledoux-stable models, we implement improved atmospheric boundary conditions that account for composition-dependent effective temperatures and systematically explore the impact of varying the parameter R _ρ , which allows one to explore in an approximate way the efficiency of semiconvection. For both Jupiter and Saturn, we construct models spanning from R _ρ = 1 (Ledoux) to R _ρ = 0 (Schwarzschild), and identify best-fit solutions that match each planet’s effective temperature, equatorial radius, lower-order gravitational moments, and atmospheric composition at 4.56 Gyr. We find that lower R _ρ values lead to stronger convective mixing, resulting in higher surface metallicities and lower deep interior temperatures, while requiring reduced heavy-element masses and lower initial entropies to stabilize the dilute inner cores. Our Saturn models also broadly agree with the observed Brunt–Väisälä frequency profile inferred from Cassini ring seismology, with stable layers arising from both the helium rain region and the dilute core. These findings support the presence of complex, compositionally stratified interiors in both gas giants.
The connection between the binary black hole (BBH) mergers observed by LIGO-Virgo-KAGRA and their stellar progenitors remains uncertain. Specifically, the fraction ϵ of stellar mass that ends up in BBH mergers and the delay time τ between star formation and merger carry information about the astrophysical processes that produce merging BBHs. We model the merger rate in terms of cosmic star formation, coupled with a metallicity-dependent efficiency ϵ and a distribution of delay times τ , and infer these parameters with data from the Third Gravitational-Wave Transient Catalog. The progenitors to merging BBHs preferentially form in low-metallicity environments with a low-metallicity efficiency of ${\mathrm{log}}_{10}{\epsilon }_{\lt {Z}_{t}}=-{3.99}_{-0.87}^{+0.68}$ and a high-metallicity efficiency of ${\mathrm{log}}_{10}{\epsilon }_{\lt {Z}_{t}}=-{4.60}_{-0.34}^{+0.30}$ at 90% credibility. The data also prefer short delay times. For a power-law distribution p ( τ ) ∝ τ ^α , we find ${\tau }_{\min }\lt 1.9\,\mathrm{Gyr}$ and α < −1.32 at 90% credibility. Our model allows us to extrapolate the mass density in BBHs to high redshifts. We cumulatively integrate our density rate over time to get the total density of merging stellar-mass BBHs as a function of redshift. Today, BBH mergers are only ∼0.01% of the total stellar-mass density created by >10 M _⊙ progenitors. However, because massive stars are short lived, there may be more mass in merging BBHs than in living massive stars as early as ∼2.5 Gyr ago. We also compare to the mass in supermassive black holes, finding that the densities were comparable ∼12.5 Gyr ago, but their densities quickly increased to ∼75 times the density in merging stellar-mass BBHs by z ∼ 1.
Vinícius Barros da Silva, João Peres Vieira, Edson Denis Leonel
The detection of limit cycles of differential equations poses a challenge due to the type of the nonlinear system, the regime of interest, and the broader context of applicable models. Consequently, attempts to solve Hilbert’s sixteenth problem on the maximum number of limit cycles of polynomial differential equations have been uniformly unsuccessful due to failing results and their lack of consistency. Here, the answer to this problem is finally obtained through information geometry, in which the Riemannian metrical structure of the parameter space of differential equations is investigated with the aid of the Fisher information metric and its scalar curvature R. We find that the total number of divergences of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>|</mo><mi mathvariant="normal">R</mi><mo>|</mo></mrow></semantics></math></inline-formula> to infinity provides the maximum number of limit cycles of differential equations. Additionally, we demonstrate that real polynomial systems of degree <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>≥</mo><mn>2</mn></mrow></semantics></math></inline-formula> have the maximum number of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>(</mo><mn>4</mn><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>−</mo><mn>2</mn><mo>)</mo></mrow></semantics></math></inline-formula> limit cycles. The research findings highlight the effectiveness of geometric methods in analyzing complex systems and offer valuable insights across information theory, applied mathematics, and nonlinear dynamics. These insights may pave the way for advancements in differential equations, presenting exciting opportunities for future developments.
Since its origin in the thermodynamics of the 19th century, the concept of entropy has also permeated other fields of physics and mathematics, such as Classical and Quantum Statistical Mechanics, Information Theory, Probability Theory, Ergodic Theory and the Theory of Dynamical Systems. Specifically, we are referring to the classical entropies: the Boltzmann–Gibbs, von Neumann, Shannon, Kolmogorov–Sinai and topological entropies. In addition to their common name, which is historically justified (as we briefly describe in this review), another commonality of the classical entropies is the important role that they have played and are still playing in the theory and applications of their respective fields and beyond. Therefore, it is not surprising that, in the course of time, many other instances of the overarching concept of entropy have been proposed, most of them tailored to specific purposes. Following the current usage, we will refer to all of them, whether classical or new, simply as entropies. In particular, the subject of this review is their applications in data analysis and machine learning. The reason for these particular applications is that entropies are very well suited to characterize probability mass distributions, typically generated by finite-state processes or symbolized signals. Therefore, we will focus on entropies defined as positive functionals on probability mass distributions and provide an axiomatic characterization that goes back to Shannon and Khinchin. Given the plethora of entropies in the literature, we have selected a representative group, including the classical ones. The applications summarized in this review nicely illustrate the power and versatility of entropy in data analysis and machine learning.
We present the first James Webb Space Telescope/NIRCam-led determination of 7 < z < 9 galaxy properties based on broadband imaging from 0.8 to 5 μ m as part of the GLASS-JWST Early Release Science program. This is the deepest data set acquired at these wavelengths to date, with an angular resolution ≲0.″14. We robustly identify 13 galaxies with signal-to-noise ratio ≳ 8 in F444W from 8 arcmin ^2 of data at m _AB ≤ 28 from a combination of dropout and photometric redshift selection. From simulated data modeling, we estimate the dropout sample purity to be ≳90%. We find that the number density of these F444W-selected sources is broadly consistent with expectations from the UV luminosity function determined from Hubble Space Telescope data. We characterize galaxy physical properties using a Bayesian spectral energy distribution fitting method, finding a median stellar mass of 10 ^8.5 M _⊙ and age 140 Myr, indicating they started ionizing their surroundings at redshift z > 9.5. Their star formation main sequence is consistent with predictions from simulations. Lastly, we introduce an analytical framework to constrain main-sequence evolution at z > 7 based on galaxy ages and basic assumptions, through which we find results consistent with expectations from cosmological simulations. While this work only gives a glimpse of the properties of typical galaxies that are thought to drive the reionization of the universe, it clearly shows the potential of JWST to unveil unprecedented details of galaxy formation in the first billion years.
Abstract The application of transformation optics to the development of intriguing electromagnetic devices can produce weakly anisotropic or isotropic media with the assistance of quasi-conformal and/or conformal mapping, as opposed to the strongly anisotropic media produced by general mappings; however, it is typically limited to two-dimensional applications. By addressing the conformal mapping between two manifolds embedded in three-dimensional space, we demonstrate that electromagnetic surface waves can be controlled without introducing singularity and anisotropy into the device parameters. Using fruitful surface conformal parameterization methods, a near-perfect conformal mapping between smooth manifolds with arbitrary boundaries can be obtained. Illustrations of concealing and illusions, including surface Luneburg and Eaton lenses and black holes for surface waves, are provided. Our work brings the manipulation of surface waves at microwave and optical wavelengths one step closer.
The healthy function of the vestibular system (VS) is of vital importance for individuals to carry out their daily activities independently and safely. This study carries out Tsallis entropy (TE)-based analysis on insole force sensor data in order to extract features to differentiate between healthy and VS-diseased individuals. Using a specifically developed algorithm, we detrend the acquired data to examine the fluctuation around the trend curve in order to consider the individual’s walking habit and thus increase the accuracy in diagnosis. It is observed that the TE value increases for diseased people as an indicator of the problem of maintaining balance. As one of the main contributions of this study, in contrast to studies in the literature that focus on gait dynamics requiring extensive walking time, we directly process the instantaneous pressure values, enabling a significant reduction in the data acquisition period. The extracted feature set is then inputted into fundamental classification algorithms, with support vector machine (SVM) demonstrating the highest performance, achieving an average accuracy of 95%. This study constitutes a significant step in a larger project aiming to identify the specific VS disease together with its stage. The performance achieved in this study provides a strong motivation to further explore this topic.
Tsuyoshi Tokuoka, Akio K. Inoue, Takuya Hashimoto
et al.
We present new observations with the Atacama Large Millimeter/submillimeter Array for a gravitationally lensed galaxy at z = 9.1, MACS1149-JD1. [O iii ] 88 μ m emission is detected at 10 σ with a spatial resolution of ∼0.3 kpc in the source plane, enabling the most distant morphokinematic study of a galaxy. The [O iii ] emission is distributed smoothly without any resolved clumps and shows a clear velocity gradient with Δ V _obs /2 σ _tot = 0.84 ± 0.23, where Δ V _obs is the observed maximum velocity difference and σ _tot is the velocity dispersion measured in the spatially integrated line profile, suggesting a rotating system. Assuming a geometrically thin self-gravitating rotation disk model, we obtain ${V}_{\mathrm{rot}}/{\sigma }_{V}={0.67}_{-0.26}^{+0.73}$ , where V _rot and σ _V are the rotation velocity and velocity dispersion, respectively, still consistent with rotation. The resulting disk mass of ${0.65}_{-0.40}^{+1.37}\times {10}^{9}$ M _⊙ is consistent with being associated with the stellar mass identified with a 300 Myr old stellar population independently indicated by a Balmer break in the spectral energy distribution. We conclude that the most of the dynamical mass is associated with the previously identified mature stellar population that formed at z ∼ 15.
Abstract The standard polar cap (PC) indices, PCN (North) based on magnetic data from Qaanaaq in Greenland and PCS (South) based on data from Vostok in Antarctica, have been submitted from the Arctic and Antarctic Research Institute in St. Petersburg, Russia, the Danish Meteorological Institute, and the Danish Space Research Institute in different versions. In order to consolidate PCS indices based on Vostok data or replace poor or missing index data, derivation procedures have been developed to generate alternative PCS index values based on data from Dome Concordia (Dome‐C) magnetic observations from epoch 2009–2020 of solar cycle 24. The reference levels and calibration parameters needed for calculations of Dome‐C‐based PCS values in post‐event and real‐time versions are defined and explained in the present work. Assessments of the new PCS index have shown its unprecedented high relevance. Part of the methods used here, such as the quiet reference level construction and the correlation and regression procedures used for calculations of scaling parameters, deviate from corresponding features considered inadequate of the International Association for Geomagnetism and Aeronomy‐endorsed PC index derivation methods.
Recent studies have shown that complex systems are often best represented by generalized networks such as hypergraphs, multilayer networks, and temporal networks. Here, the authors propose a unified framework to investigate cluster synchronization patterns in generalized networks and demonstrate the existence of chimera states that emerge exclusively in the presence of higher-order interactions.
Grigoryev V.M., Demidov M.L., Kolobov D.Yu.
et al.
One of the most important problems of modern solar physics is the observation of the small-scale structure of the solar atmosphere at various heights (including the chromosphere and corona) in different spectral lines. Such observations can be made only with large solar telescopes whose main mirror has a diameter of at least 3 m. Currently, several large solar telescopes are under construction or development in the world. In 2013 in Russia, the work began on the development of a national large solar telescope with a mirror 3 m in diameter (LST-3), which is a part (subproject) of the National Heliogeophysical Complex of the Russian Academy of Sciences. The telescope is planned to be located in the Sayan Solar Observatory at an altitude of more than 2000 m. The choice was made in favor of the classic axisymmetric Gregory optical layout on an alt-azimuth mount. The scientific equipment of LST-3 will consist of several systems of narrow-band tunable filters and spectrographs for various wave ranges. The equipment will be placed both in the main coude focus on a rotating platform and in the Nasmyth focus. To achieve a diffraction resolution, high-order adaptive optics (AO) will be used. It is assumed that with a certain modification of the optical configuration, LST-3 will work as a 0.7 m mirror coronograph in near infrared lines and can also be used for observing astrophysical objects in the nighttime.
Javier E. Contreras-Reyes, Carola Hernández-Santoro
The southern Humboldt Current ecosystem is an important topic among researchers working on the drivers of pelagic species’ biological indicators. While sea surface temperature is believed to be a major driver in anchovies’ (<i>Engraulis ringens</i>) reproductive and body condition indicators, this paper shows that regional drivers such as Pacific decadal oscillation anomalies also influence these biological processes. In addition, a warm condition could trigger increased gonad development of anchovies and synchronization of body condition dynamics with local environmental conditions stemming from sea turbulence and Ekman transport. To test the statistical significance of causality between two time series and determine the direction of causality, the frequency-domain Granger-causality method is considered. Therefore, this study provides additional predictive information, derived from past data on anchovy reproductive and feeding activities. The study could be useful for researchers working on relationships of environmental conditions and pelagic species to predict biological processes’ maximum and minimum peak movements and anchovy abundance in the southern Humboldt Current ecosystem.
L. A. Harland-Lang, M. Tasevsky, V. A. Khoze
et al.
Abstract We present the results of the new SuperChic 4 Monte Carlo implementation of photon-initiated production in proton–proton collisions, considering as a first example the case of lepton pair production. This is based on the structure function calculation of the underlying process, and focusses on a complete account of the various contributing channels, including the case where a rapidity gap veto is imposed. We provide a careful treatment of the contributions where either (single dissociation), both (double dissociation) or neither (elastic) proton interacts inelastically and dissociates, and interface our results to Pythia for showering and hadronization. The particle decay distribution from dissociation system, as well the survival probability for no additional proton–proton interactions, are both fully accounted for; these are essential for comparing to data where a rapidity gap veto is applied. We present detailed results for the impact of the veto requirement on the differential cross section, compare to and find good agreement with ATLAS 7 TeV data on semi-exclusive production, and provide a new precise evaluation of the background from semi-exclusive lepton pair production to SUSY particle production in compressed mass scenarios, which is found to be low.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Abstract With the potential for the improvements of measurement precision, the refinement of theoretical calculation on hadronic B weak decays is necessary. In this paper, we study the contributions of B mesonic distribution amplitude $${\Phi }_{B2}$$ ΦB2 within the QCD factorization approach, and find that $${\Phi }_{B2}$$ ΦB2 contributes to only the nonfactorizable annihilation amplitudes for the B $${\rightarrow }$$ → PP decays (P denotes the ground SU(3) pseudoscalar mesons). Although small, the $${\Phi }_{B2}$$ ΦB2 contributions might be helpful for improving the performance of the QCD factorization approach, especially for the pure annihilation $$B_{d}$$ Bd $${\rightarrow }$$ → $$K^{+}K^{-}$$ K+K- and $$B_{s}$$ Bs $${\rightarrow }$$ → $${\pi }^{+}{\pi }^{-}$$ π+π- decays.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Recently, Odrzywolek and Rafelski have found three distinct categories of exoplanets, when they are classified based on density. We first carry out a similar classification of exoplanets according to their density using the Gaussian Mixture Model, followed by information theoretic criterion (AIC and BIC) to determine the optimum number of components. Such a one-dimensional classification favors two components using AIC and three using BIC, but the statistical significance from both the tests is not significant enough to decisively pick the best model between two and three components. We then extend this GMM-based classification to two dimensions by using both the density and the Earth similarity index, which is a measure of how similar each planet is compared to the Earth. For this two-dimensional classification, both AIC and BIC provide decisive evidence in favor of three components.
In this paper, we investigate the effects of spin squeezing on two-coupled quantum kicked tops, which have been previously shown to exhibit a quantum signature of chaos in terms of entanglement dynamics. Our results show that initial spin squeezing can lead to an enhancement in both the entanglement rate and the asymptotic entanglement for kicked tops when the initial state resides in the regular islands within a mixed classical phase space. On the other hand, we found a reduction in these two quantities if we were to choose the initial state deep inside the chaotic sea. More importantly, we have uncovered that an application of periodic spin squeezing can yield the maximum attainable entanglement entropy, albeit this is achieved at a reduced entanglement rate.