Sazuna/UAT_keywords huggingface dataset:
GRB 221009A and the Apparently Most Energetic Gamma-Ray Bursts. Gamma-ray bursts (GRBs) are often referred to as the most luminous explosions in the Universe, due to their short and highly luminous prompt emission. This apparent luminosity, however, does not reflect the true energy budget of the prompt emission, which is strongly beamed. Accurate estimations of the energy radiated during the prompt phase require taking the geometry of GRB jets into account, which remains poorly known. Nevertheless, one may establish the distribution of well-measured quantities, like Eiso, the GRB isotropic equivalent energy, which encrypts crucial information about GRB jets, with the aim of providing constraints on the jet's radiated energy. In this work, we study the bright end of the GRB isotropic equivalent energy distribution (hereafter called "apparent energy"), using an updated sample of 185 apparently energetic GRBs with Eiso ≥ 1053 erg. This new sample includes GRB 221009A, allowing us to discuss this apparently superenergetic GRB in the context of the general Eiso distribution of long GRBs. We describe the construction of the sample and compare three fits of the Eiso distribution with a simple power law, a cutoff power law, and a broken power law. Our study confirms the existence of a cutoff around Eiso = 4 × 1054 erg, even when GRB 221009A is included in the sample. Based on this finding, we discuss the possible reasons behind the rapid decrease in the number of apparently energetic gamma-ray bursts beyond Eiso = 4 × 1054 erg and the interpretation of GRB 221009A, the most apparently energetic GRB detected to date, in this context.

Keywords: Gamma-ray bursts
The AURORA Survey: A New Era of Emission-line Diagrams with JWST/NIRSpec. We present results on the emission-line properties of z = 1.4–7.5 star-forming galaxies in the Assembly of Ultradeep Rest-optical Observations Revealing Astrophysics (AURORA) Cycle 1 JWST/NIRSpec program. Based on its depth, continuous wavelength coverage from 1 to 5 μm, and medium spectral resolution (R ∼ 1000), AURORA includes detections of a large suite of nebular emission lines spanning a broad range in rest-frame wavelength. We investigate the locations of AURORA galaxies in multiple different emission-line diagrams, including traditional BPT diagrams of [O III]λ5007/Hβ versus [N II]λ6583/Hα, [S II]λλ6717, 6731/Hα, and [O I]λ6300/Hα, and the ionization–metallicity diagram of [O III]λ5007/[O II]λ3727 (O32) versus ([O III]λ5007+[O II]λ3727)/Hβ (R23). We also consider a bluer rest-frame ionization–metallicity diagram introduced recently to characterize z &gt; 10 galaxies, [Ne III]λ3869/[O II]λ3727 versus ([Ne III]λ3869+[O II]λ3727)/Hδ, as well as longer-wavelength diagnostic diagrams extending into the rest-frame near-IR: [O III]λ5007/Hβ versus [S III]λλ9069, 9532/[S II]λλ6717, 6731 (S32), and He Iλ1.083 μm/Paγ and [S III]λ9532/Paγ versus [Fe II]λ1.257μm/Paβ. With a significant boost in signal-to-noise ratio and large, representative samples of individual galaxy detections, the AURORA emission-line diagrams presented here definitively confirm a physical picture in which chemically young, α-enhanced, massive stars photoionize the interstellar medium (ISM) in distant galaxies with a harder ionizing spectrum at fixed nebular metallicity than in their z ∼ 0 counterparts. We also uncover previously unseen evolution prior to z ∼ 2 in the [O III]λ5007/Hβ versus [N II]λ6583/Hα diagram, which motivates deep NIRSpec observations at even higher redshift. Finally, we present the first statistical sample of rest-frame near-IR emission-line diagnostics in star-forming galaxies at high redshift. In order to truly interpret rest-frame near-IR line ratios including [Fe II]λ1.257 μm, we must obtain better constraints on dust depletion in the high-redshift ISM.

Keywords: Interstellar medium, Galaxy formation, High-redshift galaxies, Emission line galaxies
A Method for Estimating X-Ray Pulsar Period and Pulse Time Delay: Applying the Improved <inline-formula> </inline-formula>-test to Complex Profiles. In order to apply the Z2 statistic to the estimation of the navigation pulsar period and time delay, and thus further improve the accuracy of X-ray pulsar navigation, this paper proposes a method for estimating the pulsar period and time delay with complex profiles based on the improved  -test. Based on the prior information of the amount of photon data in the observation task, this method adaptively determines the optimal harmonic truncation order under different data qualities. In order to solve the problem of the change rate of complex profile signals being too fast, the binned data is rephased according to the principle of equal photon intensity segmentation within the bin, and the optimal number of bins suitable for the PSR B0531+21 pulsar is selected. Through simulation, a quantitative analysis was conducted on factors that affect the performance of the estimation algorithm, such as observation time, detector area, noise interference, etc. Simulation results show that the proposed estimation method has greater advantages when the observation time is short, the detector area is small, and the interference noise is large. In addition, the observation data of the PSR B0531+21 pulsar is processed and analyzed. The period estimation accuracy of the method proposed is 3.6532 ns, which is 39.57% higher than that of the χ2-test method. The method we proposed has the advantages of being suitable for navigation pulsars, strong environmental adaptability, high estimation accuracy, and strong estimation stability, which can further improve the performance of X-ray pulsar navigation.

Keywords: Period search , Astronomy data analysis, X-ray stars, Pulsars
Modeling Tidal Streams and Tidal Tails around Galaxies Using Deep Wendelstein Imaging Data. From the Λ cold dark matter paradigm, it is expected that galaxies merge and grow in their environments. These processes form various tidal features depending on the merger mass ratio, orbital parameters, and gas richness. We inspected 170  -band Abell cluster observations from the 2.1 m Fraunhofer-Teleskop Wendelstein and identify 111 of such features from which we select nine streams and five tails. A fast and innovative technique was developed for determining their photometric properties. The model is a Gaussian, including higher-order moments to describe the light profile in slices perpendicular to the elongation direction. From these models, FWHM apertures are generated. The method was developed, tested, and applied on the selected features and corresponding g- and r-band data from the Legacy Survey DR10. Regarding the novel modeling approach, we can measure surface and total brightnesses with precisions of 4% and 7%, respectively. Mean stream width precision, which also translates to the mean Re along the feature is on average within 3% uncertainty. The measured streams have on average a surface brightness of   mag arcsec‑2 and are dimmer than the tails in our sample (  mag arcsec‑2). We infer that the progenitors of our streams can come from dwarfs, early-type galaxies or disks, based on the streams structural parameters. Furthermore, brightnesses and colors of the streams and tails are consistent with those of galaxies that populate the red sequence in the Coma cluster within 2σ.

Keywords: Stellar streams, Galaxy interactions, Tidal tails, Galaxy mergers, Photometry, Galaxy evolution, Extragalactic astronomy
Measuring the Intracluster Light Fraction with Machine Learning. The intracluster light (ICL) is an important tracer of a galaxy cluster's history and past interactions. However, only small samples have been studied to date due to its very low surface brightness and the heavy manual involvement required for the majority of measurement algorithms. Upcoming large imaging surveys such as the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) are expected to vastly expand available samples of deep cluster images. However, to process this increased amount of data, we need faster, fully automated methods to streamline the measurement process. This paper presents a machine learning model designed to automatically measure the ICL fraction in large samples of images, with no manual preprocessing required. We train the fully supervised model on a training data set of 50,000 images with injected artificial ICL profiles. We then transfer its learning onto real data by fine-tuning with a sample of 101 real clusters with their ICL fraction measured manually using the surface brightness threshold method. With this process, the model is able to effectively learn the task and then adapt its learning to real cluster images. Our model can be directly applied to Hyper Suprime-Cam images, processing up to 500 images in a matter of seconds on a single GPU, or fine-tuned for other imaging surveys such as LSST, with the fine-tuning process taking just 3 minutes. The model could also be retrained to match other ICL measurement methods. Our model and the code for training it are made available on GitHub.

Keywords: Galaxy clusters, Convolutional neural networks, Galactic and extragalactic astronomy
Planetary Rhythms: Synchronous Circulation on Variably Irradiated Asynchronous Planets. Tidal locking of planets to their host stars results in an atmospheric circulation with a hotspot fixed to the frame of reference of the planet. On the other hand, asynchronously rotating planets feature moving hotspots either lagging or leading the corresponding substellar point as it translates along the surface. We show that a planet falling in the latter category could mimic the circulation of tidally synchronous planets under the influence of time-varying instellation, possibly provided by pulsating or multiple star systems. This happens when the planet's diurnal period is in resonance with the period of instellation variation, leading to a planet-frame-fixed hotspot. Slight differences in the above periods lead to east–west or west–east creeping hotspots with a period significantly longer than both. The rate of hotspot motion is given by the difference between the diurnal and instellation variation rates, similar to the lower envelope frequency of beat patterns formed by two superposed waves in linear wave theory. We call this phenomenon "beating." A combination of the radiative, rotational, wave propagation, and drag timescales establishes dynamical constraints on beating. Based on this, we classify a set of Kepler and TESS circumbinary planets with two candidates exhibiting climatic departures from the no-variation scenario. In general, hotter and faster-spinning planets are more susceptible to climatic departures. Beating, if it occurs, may additionally create optimistic extensions of habitable zones for corresponding systems.

Keywords: Exoplanet atmospheric variability, Planetary atmospheres, Habitable zone, Atmospheric dynamics, Habitable planets
Exploring the Neutrino Mass Hierarchy from Isotopic Ratios of Supernova Nucleosynthesis Products in Presolar Grains. We study the nucleosynthesis in a core-collapse supernova (CCSN) model including newly calculated neutrino-induced reaction rates with both collective and Mikheyev–Smirnov–Wolfenstein neutrino flavor oscillations considered. We show that the measurement of a pair of 11B/10B and 138La/139La or 6Li/7Li and 138La/139La in presolar grains that are inferred to have originated from CCSNs could constrain the neutrino mass hierarchy. The new shell model and the model of quasiparticle random phase approximation in the estimate of three important neutrino-induced reactions, ν + 16O, ν + 20Ne, and ν + 138Ba, are applied in our reaction network. The new rates decrease the calculated 7Li/6Li ratio by a factor of 5 compared with the previous study. More interestingly, these new rates result in a clear separation of the isotopic ratio of 11B/10B between normal and inverted mass hierarchies in the O/Ne, O/C, and C/He layers, where 138La abundance depends strongly on the mass hierarchy. In these layers, the sensitivity of the calculated abundances of 10,11B and 6,7Li to the nuclear reaction uncertainties is also tiny. Therefore, we propose that the 11B/10B versus 138La/139La and 6Li/7Li versus 138La/139La in type X silicon carbide grains sampled material from C/He layer can be used as a new probe to constrain the neutrino mass hierarchy.

Keywords: Neutrino oscillations, Explosive nucleosynthesis, Meteorite composition, Core-collapse supernovae
Chemical Evolution of Isotopically Labeled Carbon Dioxide (<SUP>13</SUP>CO<SUB>2</SUB>) Ice Exposed to Ionizing Radiation and Implications for Trans-Neptunian Objects. We present results on the radiation chemistry of isotopically labeled carbon dioxide (13CO2) ices induced by energetic electrons at 40 and 10 K to simulate the chemical evolution of carbon dioxide on trans-Neptunian objects exposed to galactic cosmic-ray particles. By collecting infrared spectra during the irradiation of 13CO2 ices, we have identified several radiolysis products, including carbon monoxide (13CO), ozone (O3), carbon trioxide (13CO3) with cyclic (C2v) and acyclic (D3h) isomers, carbon tetraoxide (13CO4), carbon pentaoxide (13CO5), and carbon hexaoxide (13CO6). The temporal profiles reveal that all products exhibit a rapid increase followed by a gradual decrease during prolonged irradiation, with the reduction at 40 K occurring faster than at 10 K. Furthermore, the ratio of 13CO to 13CO2 rises to constants of 0.20 at 40 K and 0.27 at 10 K as radiation accumulates within ices, which has potential implications for understanding the specific conditions of trans-Neptunian objects, such as galactic cosmic-ray exposure history, or other astrophysical scenarios characterized by abundant carbon dioxide.

Keywords: Surface composition, Laboratory astrophysics, Carbon dioxide, Surface ices, Trans-Neptunian objects
Can Dark Stars Account for the Star Formation Efficiency Excess at Very High Redshifts?. The James Webb Space Telescope (JWST) has recently conducted observations of massive galaxies at high redshifts, revealing a notable anomaly in their star formation efficiency (SFE). Motivated by the recent identification of three ~106M⊙ dark star candidates, we investigate whether dark stars can be the origin of the SFE excess. It turns out that the excess can be reproduced by a group of dark stars with M ≳ 103 M⊙, because of their domination in generating primary UV radiation in high-redshift galaxies. The genesis of these dark stars is attributed to the capture of weakly interacting massive particles within a mass range of tens of gigaelectronvolts to a few teraelectronvolts. However, if the top-heavy initial mass function of dark stars holds up to ~105 M⊙, the relic black holes stemming from their collapse would be too abundant to be consistent with the current observations of massive compact halo objects. We thus suggest that just a small fraction of SFE excess may be contributed by the very massive dark stars, with the majority likely originating from other sources, such as the Population III stars, in view of their rather similar UV radiation efficiencies.

Keywords: Star formation, Supermassive black holes, High-redshift galaxies, Dark matter
Effect of Lyα Radiative Transfer on Intensity Mapping Power Spectra. Clustering of Lyα-emitting galaxies (LAEs) and Lyα line intensity mapping (LIM) are useful probes of cosmology. However, Lyα radiative transfer (RT) effects, such as absorption, line shift, and line broadening, and their dependence on the large-scale density and velocity fields can modify the measured LAE clustering and LIM statistics. We explore the effects of RT on the Lyα LIM power spectrum in two ways: using an analytic description based on linear approximations, and using lognormal mocks. The qualitative effects of intergalactic Lyα absorption on the LIM auto- and cross-power spectrum include a scale-dependent, reduced effective bias, reduced mean intensity, and modified redshift-space distortions. The linear absorption model does not describe the results of the lognormal simulations well. The random line shift suppresses the redshift-space power spectrum similar to the Fingers-of-God effect. In cross-correlation of LAEs or Lyα intensity with a non-Lyα tracer, the Lyα line shift leads to a phase shift of the complex power spectrum, i.e., a cosine damping of the real part. We study the impact of Lyα RT effects on the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) LAE and LIM power spectra using lognormal mocks. We find that even small amounts of IGM absorption will significantly change the measured LAE auto-power spectrum. The LAE-intensity cross-power spectrum stays within the measurement uncertainty. Therefore, HETDEX will be able to constrain Lyα RT effects.

Keywords: Lyman-alpha galaxies, Observational cosmology, Large-scale structure of the universe
Geometry of the Comptonization Region of MAXI J1348‑630 through Type-C Quasiperiodic Oscillations with NICER. We use the rms and lag spectra of the type-C quasiperiodic oscillation (QPO) to study the properties of the Comptonization region (aka corona) during the low/hard and hard-intermediate states of the main outburst and reflare of MAXI J1348‑630. We simultaneously fit the time-averaged energy spectrum of the source and the fractional rms and phase-lag spectra of the QPO with the time-dependent Comptonization model VKOMPTH. The data can be explained by two physically connected coronae interacting with the accretion disk via a feedback loop of X-ray photons. The best-fitting model consists of a corona of ∼103 km located at the inner edge of the disk and a second corona of ∼104 km horizontally extended and covering the inner parts of the accretion disk. The properties of both coronae during the reflare are similar to those during the low/hard state of the main outburst, reinforcing the idea that both the outburst and the reflare are driven by the same physical mechanisms. We combine our results for the type-C QPO with those from previous work focused on the study of type-A and type-B QPOs with the same model to study the evolution of the geometry of the corona through the whole outburst, including the reflare of MAXI J1348‑630. Finally, we show that the sudden increase in the phase-lag frequency spectrum and the sharp drop in the coherence function previously observed in MAXI J1348‑630 are due to the type-C QPO during the decay of the outburst and can be explained in terms of the geometry of the coronae.

Keywords: Stellar accretion disks, Low-mass x-ray binary stars, X-ray binary stars, Black holes
Turbulence and Magnetic Field Alignment in Small Molecular Clouds: The Role of Cloud Size, Mass, and Density. In this study, we investigate the relationship between turbulence (ΔV) and different physical parameters in 22 isolated small molecular clouds and their cores, extending the analysis to a hierarchical scenario from core to cloud. Using 12CO line width as a tracer of turbulence, we find that ΔV correlates with both cloud size and mass, following   and  . Further, the surface density of the clouds (Σcl) influences the ΔV–Lcl relation, with  . This indicates that gravitational energy drives turbulence in clouds, indicating possible virial equilibrium. We observe that Lcl correlates with Mcl and volume gas density of the cloud (ρcl), implying nearly constant Σcl across the clouds. In cloud cores, C18O line-width data show complex behavior, with no direct correlation between ΔV and core size (Lco). However, a positive correlation emerges when the surface density of the core is included in Lco. Notably, the relation between volume gas density (ρco) and core size (Lco) deviates from constant core surface density. Our analysis reveals that turbulent pressure increases with gravitational pressure to maintain global equilibrium. Finally, on the core-to-cloud scale, physical relationships remain continuous, reflecting the interconnected nature of clouds and cores. Extending our previous work, where we demonstrated a nonlinear dependence of turbulence on the alignment of the local magnetic field in molecular clouds with the Galactic plane, we now compare observations with a theoretical model based on kinetic theory. Our result confirms that higher turbulence causes greater magnetic misalignment consistent with the derived second-order polynomial relationship.

Keywords: Interstellar dynamics, Stellar kinematics, Star forming regions, Molecular clouds, Interstellar magnetic fields, Star formation, Magnetic fields
Stream Members Only: Data-driven Characterization of Stellar Streams with Mixture Density Networks. Stellar streams are sensitive probes of the Milky Way's gravitational potential. The mean track of a stream constrains global properties of the potential, while its fine-grained surface density constrains galactic substructure. A precise characterization of streams from potentially noisy data marks a crucial step in inferring galactic structure, including the dark matter, across orders of magnitude in mass scales. Here we present a new method for constructing a smooth probability density model of stellar streams using all of the available astrometric and photometric data. To characterize a stream's morphology and kinematics, we utilize mixture density networks to represent its on-sky track, width, stellar number density, and kinematic distribution. We model the photometry for each stream as a single-stellar population, with a distance track that is simultaneously estimated from the stream's inferred distance modulus (using photometry) and parallax distribution (using astrometry). We use normalizing flows to characterize the distribution of background stars. We apply the method to the stream GD-1, and the tidal tails of Palomar 5. For both streams we obtain a catalog of stellar membership probabilities that are made publicly available. Importantly, our model is capable of handling data with incomplete phase-space observations, making our method applicable to the growing census of Milky Way stellar streams.

Keywords: Globular star clusters, Astrodynamics, Milky Way dark matter halo, Stellar streams, Neural networks, Galaxy structure, Gaussian mixture model, Astrostatistics, Mixture model, Orbit determination
Study on the Responses in the Transition Region of Coronal Extreme-ultraviolet Waves. Coronal extreme-ultraviolet (EUV) waves are globally propagating disturbances in the solar atmosphere. The existence of coronal EUV waves was predicted by chromospheric Moreton–Ramsey waves. It is widely accepted that Moreton–Ramsey waves represent the chromospheric imprints of coronal EUV waves that compress downward during their lateral propagations. Hence, coronal EUV waves should inevitably compress the interlayer between the corona and the chromosphere, the transition region (TR), before reaching the chromosphere. However, the responses in the TR of coronal EUV waves lack enough attention. Here, we focus on the wave signatures in He II 304 Å for a sample of 640 coronal EUV waves from 2010 to 2021, aiming to establish a "bridge" connecting coronal EUV waves and chromospheric Moreton–Ramsey waves. It is found that ∼14.4% of all coronal EUV waves have TR responses, and ∼34.5% of "disk events" with TR responses have chromospheric imprints. We specifically analyze the wave front characteristics of disk events with TR responses (58). Statistical analysis shows that TR responses for coronal EUV waves have an average speed of 495.58 ± 27.62 km s‑1, an average duration of 488.4 ± 12 s, an average angular width of 71 22, and an average intensity enhancement ratio (IER) of 30.39%. Moreover, all TR responses with chromospheric imprints display a greater inclination angle (&gt;50°) and a larger IER (&gt;30%). All the results suggest that TR responses can be indicators of missing Moreton–Ramsey waves and clarify the resolution of the mystery of the rarity of Moreton–Ramsey waves.

Keywords: Solar chromosphere, Solar coronal waves, Solar corona, Solar transition region