Sazuna/UAT_keywords huggingface dataset:
Monopole Fluctuations in Galaxy Surveys. Galaxy clustering provides a powerful way to probe cosmology. This requires understanding of the background mean density of galaxy samples, which is estimated from the survey itself by averaging the observed galaxy number density over the angular position. The angle average includes not only the background mean density but also the monopole fluctuation at each redshift. Here for the first time we compute the monopole fluctuations in galaxy surveys and investigate their impact on galaxy clustering. The monopole fluctuations vary as a function of redshift, and it is correlated with other fluctuations, affecting the two-point correlation function measurements. In an idealized all-sky survey, the rms fluctuation at z = 0.5 can be as large as 7% of the two-point correlation function in amplitude at the baryonic acoustic oscillation scale, and it becomes smaller than 1% at z &gt; 2. The monopole fluctuations are unavoidable, but they can be modeled. We discuss its relation to the integral constraint and the implications for the galaxy clustering analysis.

Keywords: Baryon acoustic oscillations, Large-scale structure of the universe
Quantum Bayesian Inference with Renormalization for Gravitational Waves. Advancements in gravitational-wave (GW) interferometers, particularly the next generation, are poised to enable the detections of orders of magnitude more GWs from compact binary coalescences. While the surge in detections will profoundly advance GW astronomy and multimessenger astrophysics, it also poses significant computational challenges in parameter estimation. In this work, we introduce a hybrid quantum algorithm QBIRD, which performs quantum Bayesian inference with renormalization and downsampling to infer GW parameters. We validate the algorithm using both simulated and observed GWs from binary black hole mergers on quantum simulators, demonstrating that its accuracy is comparable to classical Markov Chain Monte Carlo methods. Currently, our analyses focus on a subset of parameters, including chirp mass and mass ratio, due to the limitations from classical hardware in simulating quantum algorithms. However, QBIRD can accommodate a broader parameter space when the constraints are eliminated with a small-scale quantum computer of sufficient logical qubits.

Keywords: Markov chain Monte Carlo, Algorithms, Gravitational waves, Gravitational wave sources
A Possible Formation Scenario of the Gaia ID 3425577610762832384: Inner Binary Merger inside a Triple Common Envelope. Recently, an identified noninteracting black hole (BH) binary, Gaia ID 3425577610762832384 (hereafter G3425), contains a BH (∼3.6 M⊙) falling within the mass gap and has a nearly circular orbit, challenging the classical binary evolution and supernova theory. Here, we propose that G3425 originates from a triple through a triple common envelope (TCE) evolution. The G3425 progenitor originally may consist of three stars with masses of 1.49, 1.05, and 21.81 M⊙ and inner and outer orbital periods of 4.22 and 1961.78 days, respectively. As evolution proceeds, the tertiary fills its Roche lobe, leading to a TCE. We find that the orbital energy generated by the inspiral of the inner binary serves as additional energy imparted for ejecting the common envelope (CE), accounting for ∼97% of the binding energy in our calculations. This means that the outer orbit needs to expend only a small amount of the orbital energy to successfully eject the CE. The outcome of the TCE is a binary consisting of a 2.54 M⊙ merger produced by the inner binary merger and a 7.67 M⊙ helium star whose CE successfully ejected, with an orbital period of 547.53 days. The resulting post-TCE binary (PTB) has an orbital period that is 1–2 orders of magnitude greater than the orbital period of a successfully ejected classical binary CE. In subsequent simulations, we find that the successfully ejected helium star has a 44.2% probability of forming a BH. In the case of a noncomplete fallback forming a BH, with an ejected mass of 2.6 M⊙ and a relatively low natal kick (  km s‑1 to   km s‑1), this PTB can form G3425 in the Milky Way.

Keywords: Black holes
Juno Observations of Langmuir Waves in Association with Interplanetary Shocks from ~1.3 to ~5.4 au. Langmuir waves are often observed upstream of planetary bow shocks and interplanetary (IP) shocks. Waveform capture (WFC) measurements, obtained during Juno's cruise phase, reveal the occurrence of Langmuir waves, as well as other wave modes, in association with IP shocks and IP coronal mass ejections (ICMEs) at distances from ∼1.3 to ∼5.4 au. This is a unique database of ICME/IP shock events with WFCs in the equatorial plane in these radial distances. We identified 12 events when WFCs were obtained within 36 hr upstream of the IP shock/ICME event (10 within less than 10 hr). Langmuir waves were observed at 9, a significantly higher occurrence than has previously been reported using spectral observations from other spacecraft. The larger rate is likely due to the bursty nature of Langmuir waves in combination with the higher time resolution of WFC data compared to spectral data. Observed peak amplitudes of ∼16 mV m‑1 (peak to peak) are comparable to those observed upstream of outer planetary bow shocks. The highest peak amplitudes occurred in the strongest shocks (largest magnetic compression) and when waveforms were obtained closest to the shock. Langmuir waves were observed as much as 8 hr upstream. The WFCs provide electron density on rapid time scales, including an increase from ∼0.05 to 0.25 cm‑3 in ∼0.01 s across an IP shock ramp. Although electron measurements were not obtained, these observations provide evidence for the energization of electrons at the shock or ICME front and, in some events, for propagation over large distances while maintaining the features in the distributions necessary to destabilize Langmuir waves.

Keywords: Space plasmas, Interplanetary shocks, Solar wind, Interplanetary particle acceleration, Interplanetary magnetic fields, Solar coronal mass ejections
Granulation and Convectional Driving on Stellar Surfaces. Surface convection is important for the presence of magnetic activity at stars. So far, this convection is thought to be a result of heating from below, where convection cells rise and break up. New models reveal that surface convection is instead strongly driven by cooling from above. We compare two simulations of surface convection, one with a significant heating from below and one without. We obtain surface convection in both cases, and they show similar granulation patterns. The deep convection driven by heating from below is still evolving and asymptotically approaches a steady-state solution. We find that convection from below is not needed at all to form typical photospheric granulation. This indicates the possibility of a surface dynamo acting on stars without a convecting envelope. Even stars without a convecting envelope could therefore exhibit stronger magnetic and coronal activity than expected so far.

Keywords: Stellar convection envelopes, Solar convective zone, Solar granulation, Solar radiation, Stellar granulation
Persistent GeV Counterpart to the Microquasar GRS 1915+105. Microquasars are compact binary systems hosting collimated relativistic jets. They have long been proposed as cosmic-ray accelerators, probed via the gamma-ray emission produced by relativistic particles. However, the observational evidence is steadily increasing but limited: there are around 20 microquasars known to date, of which only 3 have so far been firmly detected in the GeV gamma-ray range, always in a flaring or special spectral state. Here we present Fermi-LAT observations of the region around the microquasar GRS 1915+105, which reveal the presence of previously unknown multi-GeV emission consistent with the position of the microquasar. No periodicity or variability is found, indicating a persistent source of gamma rays. The properties of the emission are consistent with a scenario in which protons accelerated in the jets interact with nearby gas and produce gamma rays. We find that if the jet has been operating at an average of 1% of the Eddington limit for 10% of the time that GRS 1915+105 spent in its current mass transfer state, the transfer of 10% of the available power to protons is enough to reach the ∼3 × 1049 erg required to explain the GeV signal. Therefore, our results support a scenario in which microquasars with low-mass stellar companions act as hadronic accelerators, strengthening the idea that microquasars as a class contribute to at least some fraction of the observed cosmic-ray flux.

Keywords: Gamma-ray astronomy, X-ray binary stars, Jets
Structure Functions of Rotation Measures Revealing the Origin of Fast Radio Bursts. Structure function (SF) analysis is a powerful tool for studying plasma turbulence. Theoretically, the SF of Faraday rotation measure (RM) is expected to include a geometric component due to the relative orientation of sight lines through an ordered magnetic field. However, observational evidence for this component remains elusive. Here, we report that the SFs of the binary PSR B1744–24A and the repeating fast radio burst (FRB) 20201124A exhibit both a periodic geometric component, caused by binary orbital motion, and a flat statistical component. The statistical component, induced by stochastic fluctuations in electron density and magnetic field, aligns with RM scatter derived from pulse depolarization. These findings indicate that FRB 20201124A has a binary origin and suggest that the periodic geometric component can serve as a diagnostic tool to identify binary companions.

Keywords: Radio bursts, Magnetic fields, Interstellar medium, Radio transient sources
A Universal Break in Energy Functions of Three Hyperactive Repeating Fast Radio Bursts. Fast radio bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances with a mysterious origin. Observations show that at least some FRBs are produced by magnetars. All magnetar-powered FRB models require some triggering mechanisms, among which the most popular is the cracking of the crust of a neutron star, which is called a starquake. However, so far there has been no decisive evidence for this speculation. Here we report the energy functions of the three most active repeating FRBs, which show a universal break around 1038 erg. Such a break is similar to that of the frequency–magnitude relationship of earthquakes. The break, and the change in the power-law indices below and above it, can be well understood within the framework of FRBs triggered by starquakes in the magnetar models. The seed of weak FRBs can grow both on the magnetar surface and in the deeper crust. In contrast, the triggering of strong FRBs is confined by the crustal thickness, and the seed of strong FRBs can only grow on the surface. This difference in dimensionality causes a break in the scaling properties from weak to strong FRBs, occurring at a point where the penetration depth of starquakes equals the crustal thickness. Our result, together with the earthquake-like temporal properties of these FRBs, strongly supports the idea that FRBs are triggered by starquakes, providing a new opportunity to study the physical properties of the crust of a neutron star.

Keywords: Neutron stars, Magnetars, Radio bursts, Radio transient sources
High-resolution Observations of an X-1.0 White-light Flare with Moving Flare Ribbons. We analyze high-resolution observations of an X-1.0 white-light flare, triggered by a filament eruption, on 2022 October 2. The full process of filament formation and subsequent eruption was captured in the Hα passband by the Visible Imaging Spectrograph (VIS) on board the Goode Solar Telescope (GST) within its center field of view. White-light emissions appear in flare ribbons following the filament eruption and Hα ribbon brightening. GST Broadband Filter Imager data show that the continuum intensity, as compared to the nearby quiet-Sun area, has increased by up to 20% in the photospheric TiO band around 7057 Å. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory reported 10% contrast enhancement in the continuum near Fe I 6173 Å line. The separation motion of two white-light kernels is recorded by the high-cadence GST/TiO images and is well accompanied by the motion of the VIS Hα flare ribbon leading edge. One kernel, located in a 150 Gauss field within a granulation area, exhibited an average apparent motion speed of 55 km s‑1, which is the highest average speed ever reported. The other kernel drifted at 9 km s‑1 in an 800 Gauss magnetic field area. Hard X-ray (HXR) emissions reaching up to 300 keV have been observed for this flare. The simultaneous occurrence of high-cadence HXR, microwave, and white-light emissions strongly suggests that the energetic particles from the flare directly contribute to the heating. The inverted HXR energy flux density corresponding to 10% TiO brightening is 2.07 ± 0.23 × 1011 erg cm‑2 s‑1 during the flare peak.

Keywords: Solar photosphere, Solar chromosphere, Solar white-light flares, Solar filament eruptions
A Multiwavelength Investigation of Spiral Structures in z &gt; 1 Galaxies with JWST. Recent JWST observations have revealed the prevalence of spiral structures at z &gt; 1. Unlike in the local Universe, the origin and the consequence of spirals at this epoch remain unexplored. We use public JWST/NIRCam data from the COSMOS-Web survey to map spiral structures in eight massive (&gt;1010.5 M⊙) star-forming galaxies at zspec ∼ 1.5. We present a method for systematically quantifying spiral arms at z &gt; 1, enabling direct measurements of flux distributions. Using rest-frame near-IR images, we construct morphological models accurately tracing spiral arms. We detect offsets (∼0.2–0.8 kpc) between the rest-frame optical and near-IR flux distributions across most arms. Drawing parallels to the local Universe, we conclude that these offsets reflect the presence of density waves. For 9 out of 18 arms, the offsets indicate spiral shocks triggered by density waves. In all, 5 arms have offsets in the opposite direction and are likely associated with tidal interactions. For the remaining cases with no detected offsets, we suggest that stochastic "clumpy" star formation is the primary driver of their formation. In conclusion, we find a multifaceted nature of spiral arms at z &gt; 1, similar to that in the local Universe.

Keywords: Galaxy evolution, Spiral galaxies
Luminosity Distance and Extinction by Submicrometer-sized Grains. The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be corrected. However, as the grain size increases, the extinction properties become gray, meaning these particles contribute by a constant at wavelengths  1 μm, making them undetectable by photometry in the optical. In this study, we compare the parallactic and luminosity distances of a pristine sample of 33 well-known early-type stars with nonpeculiar reddening curves and find that the luminosity distance overestimates the parallactic distance in 80% of the cases. This discrepancy can be removed when incorporating a population of large, submicrometer-sized dust grains in a dust model that provides gray extinction, which diminishes the luminosity distance accordingly.

Keywords: Interstellar dust extinction
The Formation of a Multifilament System Driven by Photospheric Converging Motions in a Bipolar Sunspot. Solar filaments are believed to be a clump of cold plasma accumulated in the magnetic dips. However, the magnetic configuration of filaments and the key factors for their formation remains elusive. In this Letter, we present a detailed study of the formation and eruption of a multifilament system with observations and simulations. Before the filament appeared visible, the chromospheric fibrils gradually gathered together, evolving from a diffuse distribution into threadlike structures that were nearly parallel to the polarity inversion lines. On 2022 March 20, an arch filament first appeared showing high dynamics, and subsequently two reserved S-shaped filaments were visibly observed. These two filament segments further reconnected, forming a long coherent filament and resulting in a double-decker configuration. In addition, continuous converging motion and magnetic flux cancellation were found in the photosphere during the evolution. Simultaneously, more bald patch structures appeared at the polarities' collision position. Through a data-driven numerical simulation, we further reconstructed the coronal magnetic field, which is composed of two twisted magnetic flux ropes (MFRs) with their bottom touching the photosphere, along with a group of sheared arcades forming an X-shaped configuration. These findings suggest that the magnetic configuration of the filament is in a highly dynamic state, evolving from a hybrid to a coherent MFR. Moreover, we propose that the formation and eruption of the multifilament system are closely related to magnetic reconnection taking place on the photosphere and in the lower corona, respectively, both mainly driven by the photospheric converging motion.

Keywords: Solar filaments, Solar magnetic reconnection
X-Ray Dips and Polarization Angle Swings in GX 13+1. We present the result from the 2024 April observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with Neutron Star Interior Composition Explorer and Swift- X-Ray Telescope coordinated observations. Two light-curve dips were observed; during them, the harder Comptonized spectral component was dominant and the polarization degree (PD) higher than in the softer, off-dip intervals. Through a joint analysis of the three IXPE observations, which also included the dip from the first observation, we demonstrate that the polarization properties varied in response to the intensity and spectral hardness changes associated with the dips. The PD attained values up to ∼4%. The polarization angle (PA) showed a swing of ∼70∘ across the dip and off-dip states, comparable to the continuous rotation seen during the first IXPE observation. We discuss these results in the context of models for polarized emission from the accretion disk and the boundary/spreading layer on the neutron star surface. We also draw attention to the role that an extended accretion disk corona or disk wind can play in generating high PDs and, possibly, swings of the PA.

Keywords: Neutron stars, Spectropolarimetry, Low-mass x-ray binary stars, Stellar accretion disks, Polarimetry
A Dual Active Black Hole Candidate with Mass Ratio ~7:1 in a Disk Galaxy. Dual active galactic nuclei (AGNs) with comparable masses are commonly witnessed among the major merged galaxies with interaction remnants. Considering almost every massive galaxy is associated with multiple dwarf satellites around it, minor mergers involving galaxies with disproportional stellar masses should be much more common than major mergers, which would naturally lead to black hole (BH) pairs with significantly different masses. However, dual AGNs generated by minor mergers involving one or two dwarf galaxies are exceptionally rare and understudied. Moreover, good estimates of the masses of both BHs are not yet available to test this idea. Here we report the evidence of a dual AGN candidate with mass ratio ~7:1 located in an undisturbed disk galaxy. We identify the central BH with mass of 9.4 × 106 M⊙ from its radio emission as well as AGN-driven galactic-scale biconical outflows. The off-centered BH generates obvious broad and narrow emission-line regions, which gives us a robust estimation of a 1.3 × 106 M⊙ BH mass. We explore alternative scenarios for explaining the observational features of this system, including the complex gas kinematics triggered by central AGN activity and dust attenuation of the broad-line region of the central BH, finding that they failed to fully account for the kinematics of both the redshifted off-centered broad and narrow emission-line components.

Keywords: Galactic winds, Galaxy kinematics, Galaxy evolution
Complex Structure around a Circumstellar Disk Caused by Interchange Instability. We perform a three-dimensional nonideal magnetohydrodynamic simulation of a strongly magnetized cloud core and investigate the complex structure caused by the interchange instability. This is the first simulation that does not use a central sink cell and calculates the long-term (&gt;104 yr) evolution even as the disk and outflow formation occur. The magnetic field dissipates inside the disk, and magnetic flux accumulates around the edge of the disk, leading to the occurrence of interchange instability. During the main accretion phase, the interchange instability occurs recurrently, disturbing the circumstellar region and forming ring, arc, and cavity structures. These are consistent with recent high-resolution observations of circumstellar regions around young protostars. The structures extend to &gt;1000 au and persist for at least 30,000 yr after protostar formation, demonstrating the dynamic removal process of magnetic flux during star formation. We find that the disk continues to grow even as interchange instability occurs, by accretion through channels between the outgoing cavities. The outflow is initially weak but becomes strong after ∼103 yr.

Keywords: Protostars, Magnetohydrodynamics, Stellar physics, Protoplanetary disks
Production, Transport, and Destruction of Dust in the Kuiper Belt: The Effects of Refractory and Volatile Grain Compositions. The Venetia Burney Student Dust Counter (SDC) on board the New Horizons spacecraft measures the spatial and size distributions of dust along its trajectory. Models based on early SDC measurements predicted a peak dust number density at a heliocentric distance of ∼40 au, followed by a rapid decline. Instead, SDC observed dust fluxes 2–3 times higher than predicted between 40 and 60 au. One potential explanation for this discrepancy is that SDC may be encountering icy grains with different dynamical behavior than previously modeled silicate grains. Due to ultraviolet photosputtering, water–ice grains rapidly erode and migrate outward, significantly contributing to the measured dust number densities only at distances ≳40 au. We present a model of silicate and ice grain dynamics in the outer solar system, considering gravitational and radiation forces and grain erosion. Using SDC data, we estimate that the mass production rate of ice grains between 0.1 and 10 μm in the Kuiper Belt (KB) would need to be 20–70 times higher than that of silicate grains. However, KB grains are expected to be refractory/volatile mixtures rather than pure silicate or ice. Thus, we briefly explore simple models of more realistic mixed-grain cases to further gauge the effects of grain composition on the equilibrium dust distribution. Future SDC measurements at greater distances will test the model predictions and further constrain silicate and ice grain production rates in the KB.

Keywords: Astrophysical dust processes, Interplanetary dust