Sazuna/UAT_keywords huggingface dataset:
ZTF IC 10 Variable Catalog. To study how massive variable stars affect their environment, we search for variability among Zwicky Transient Facility (ZTF) sources located within the optical extent of the nearby starburst galaxy IC 10. We present the ZTF IC 10 catalog, which classifies 1516 r-band sources and 864 g-band sources within a 225″ radius around IC 10 into three categories: 1388 (767) r- (g)-band nonvariables, 150 (85) r- (g)-band nonperiodic variables, and 37 (12) r- (g)-band periodic variables. Among them 101 (48) r- (g)-band nonperiodic variables and 22 (4) r- (g)-band periodic variables are inside IC 10. We verify our classification by crossmatching with previous variability catalogs and machine learning–powered classifications. Various analysis including population demographics, color–magnitude diagrams, and crossmatching with a set of different surveys and database such as Gaia, XMM-Newton, Chandra, and SIMBAD are also presented. Based on source density and parallax, we distinguish sources within IC 10 from non–IC 10 sources. For IC 10 sources, we highlight flaring supergiants, a source with a long secondary period, and periodic supergiants including a possible S Doradus luminous blue variable and candidate Miras. For non–IC 10 sources, we present superred sources and compact objects such as a possible long-period subdwarf and a periodic X-ray source. The catalog can serve as a useful database to study the connections between various types of massive stars and their host galaxies.

Keywords: Periodic variable stars, Light curve classification , Transient sources, Period search , Optical filters, Time domain astronomy, Variable stars, Transient detection
Census of Lyα Emission from ∼600 Galaxies at z = 5–14: Evolution of the Lyα Luminosity Function and a Late Sharp Cosmic Reionization. We present the statistical properties of Lyα emission in 586 galaxies at z = 4.5–14.2, observed by multiple JWST/NIRSpec spectroscopy projects, including the JADES, GLASS, CEERS, and GO/DDT programs. We obtain Lyα equivalent width (EW), Lyα escape fraction, and ionizing photon production efficiency measurements or upper limits for these galaxies, and confirm that the Lyα-emitting galaxy fraction decreases toward higher redshifts. We derive Lyα luminosity functions from z ∼ 5 to z ∼ 10–14 with the observed Lyα EW distributions and galaxy UV luminosity functions, and find an ∼3 dex decrease in number density at LLyα = 1042–1043 erg s‑1 over the redshift range. Notably, this study presents the first constraints on the Lyα luminosity function at z ∼ 8–14. We obtain the neutral hydrogen fractions of  ,  ,  , and   at z ∼ 6, 7, 8–9, and 10–14, respectively, via comparisons of the reionization models developed by seminumerical simulations with 21cmFAST explaining the observations of Lyα, UV continuum, and Planck electron optical depth. The high xH I values over z ∼ 7–14 suggest a late and sharp reionization, with the primary reionization process occurring at z ∼ 6–7. Such a late and sharp reionization is not easily explained by either a clumpy intergalactic medium or sources of reionization in a classical faint-galaxy or a bright-galaxy/active galactic nucleus (AGN) scenario, unless a very high escape fraction or AGN duty cycle is assumed at z ∼ 6–7.

Keywords: Lyman-alpha galaxies, Reionization, High-redshift galaxies, Galaxy evolution
A Morphological Identification and Study of Radio Galaxies from LoTSS DR2. I. The "Winged" Radio Galaxies. We conducted an extensive identification and analysis of various morphological classes and subclasses of radio galaxies using the latest high-resolution data from the second data release of the LOFAR Two-metre Sky Survey. This paper presents the first results of our large-scale investigation: a new catalog of "winged" radio galaxies (WRGs). These objects represent a fascinating class of irregular radio galaxies, characterized by a pair of secondary radio lobes ("wings") in addition to the primary active lobes. We identified and cataloged 621 new WRGs and 403 additional candidates. Among the confirmed winged sources, 382 are classified as "X"-shaped radio galaxies, while the remaining 239 are "Z"-shaped radio galaxies. We also estimated several basic parameters for these winged sources and performed a Fanaroff–Riley classification. Our results show that the majority of the sources (∼88%) exhibit edge-brightened radio lobes and high average radio power (  = 26.25), consistent with an FR II classification. The average spectral index between 144 MHz and 1.4 GHz is –0.84, which is steeper than that found for previously identified winged sources based on higher-frequency data from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters survey. This indicates that our study is capable of detecting fainter sources. The median linear size of the winged sources, 498 kpc, confirms that these are large-scale structures, with approximately 16% having sizes exceeding 0.7 Mpc, making them potential candidates for giant radio galaxies.

Keywords: Radio galaxies, Active galactic nuclei, Catalogs
Astronomical Image Superresolution Reconstruction with Deep Learning for Better Identification of Interacting Galaxies. Galaxy–galaxy mergers are crucial in galaxy evolution, but the tidal features around galaxies are often faint, making it difficult to identify interacting or merging galaxies. High-resolution images of galaxies can identify fine structures within galaxies, which are essential for identifying and distinguishing different substructures within merging systems. However, due to observational and instrumental limitations, galaxy data is often collected at low resolution. To further improve visual quality and enhance the details of galaxy structures, we propose a dual-branch network structure combining convolutional neural networks (CNNs) and Transformer (DBCTNet), which leverages the local characteristics of CNNs to complement the global features of Transformer. We select four representative models for comparative experiments: Real-ESRGAN, SwinIR, Hybrid Attention Transformer, and EDAT. In the experiment, we adopt a two-stage training strategy. The results from the first stage show that DBCTNet improves the peak signal-to-noise ratio by 0.13, 0.19, 0.12, and 0.11, respectively, and achieves the highest structural similarity index value of 0.5578. In the second stage, we use DBCTNet, trained in the first stage as the generator, to train the galaxy image superresolution reconstruction model based on generative adversarial networks, DBCTGAN, which aims to enhance the visual quality of the reconstructed images. In addition, we use superresolution methods as a preprocessing step in the task of interacting galaxy classification. Experimental results show that using DBCTGAN for preprocessing improves classification performance compared to other models, which further verifies its effectiveness in enhancing the quality of low-resolution images.

Keywords: Convolutional neural networks, Galaxy classification systems, Galaxy mergers, Ground-based astronomy, Interacting galaxies, Galaxies
A Systematic Analysis of the Radio Properties of 22 X-Ray-selected Tidal Disruption Event Candidates with the Australia Telescope Compact Array. We present a systematic analysis of the radio properties of an X-ray-selected sample of tidal disruption event (TDE) candidates discovered by the eROSITA telescope. We find radio sources coincident with half of the transient events (11 TDEs), with eight radio sources showing statistically significant variability over a 6 month period. We model the radio spectra of six sources with sufficiently bright radio emission and find the sources show radio spectra consistent with optically thin synchrotron emission and radio outflow minimum radii of 1016–1017 cm, velocities 0.01c–0.05c, and energies 1048–1051 erg. On comparison with the radio properties of an optically selected TDE sample at similar late times, we find no significant difference in the radio luminosity range or radio detection rate. We find a tentative positive trend with peak radio and X-ray luminosity, but require further observations to determine if this is real or due to observational bias due to the large range in distances of the events. Interestingly, none of the X-ray-selected events show late-rising radio emission, compared to 45% of radio-detected sources of an optically selected sample that showed late-rising radio emission. We propose that this may indicate that many TDEs launch radio outflows at or near peak X-ray luminosity, which can be significantly delayed from peak optical luminosity. This study presents the first systematic analysis of the radio properties of an X-ray-selected sample of TDEs, and gives insight into the possible link between the physical processes that power X-ray and radio emission in TDEs.

Keywords: Radio continuum emission, Black hole physics, Tidal disruption, Accretion
The FAST Ursa Major Supergroup H I Survey (FUMaS): Catalog and H I Mass Function. Using the Five-hundred-meter Aperture Spherical radio Telescope, we have performed an Ursa Major supergroup H I survey covering the entire UMa region centered at R.A. = 11h59m28 .s 3, decl. = 49°05'18″ with a radius of 7 .° 5. We have obtained the most complete catalog of H I sources in the UMa supergroup, containing 178 H I sources with velocities in the range 625–1213.4 km s‑1 and masses in the range 106.0–1010.1 M⊙ assuming a distance of 17.4 Mpc. Among them, 55 H I sources were detected for the first time, of which 32 do not have known optical redshifts. For these 32 sources, we have searched the DESI Legacy Surveys and found optical counterparts for 25 of them (with optical images, but no redshifts), with the remaining seven sources being pure H I clouds without an optical counterpart. We detected H I distributions in some interacting systems and discussed four small groups in detail. We computed the neutral hydrogen mass function (H I MF) of the UMa supergroup using the 1/ Vmax  method and fitting it with the nonlinear least-squares (NLLS) and modified maximum likelihood (MML) methods. We obtained the following H I MF parameters: log10(ϕ*/Mpc‑3) = ‑0.78 ± 0.15, α = ‑1.05 ± 0.07, and log10(M*/M⊙) = 9.87 ± 0.19 for the NLLS method, and log10(ϕ*/Mpc‑3) = ‑0.70 ± 0.11, α = ‑1.05 ± 0.05, and log10(M*/M⊙) = 9.77 ± 0.13 for the MML method. This result is similar to that derived from the Very Large Array blind survey, but the slope is steeper because we detected more low-mass galaxies. The slope is flatter than that of the global H I MF, which agrees with the theoretical prediction that galaxies in high-density regions are stripped of gas due to interactions.

Keywords: Galaxy clusters, Surveys, Extragalactic radio sources, H I line emission, Catalogs
Massive Acquisition of Ultraviolet Color Excess Information from GALEX and UVOT Bands. This study employs stellar parameters from spectroscopic surveys and Zhang et al. (2023) based on Gaia BP/RP (XP) spectra, along with photometric data from Galaxy Evolution Explorer (GALEX), UV/Optical Telescope (UVOT), and Gaia, to obtain extensive ultraviolet color excess information for the relevant bands of GALEX and UVOT. By considering the impact of stellar parameters (Teff, [Fe/H], and  logg ) on intrinsic color indices and utilizing the blue-edge method combined with a random forest algorithm, an empirical relationship between stellar parameters and intrinsic ultraviolet color indices is established. By combining observed color indices, the study derives color excesses for 11,624,802 and 65,531 stars in the GALEX/near-UV and far-UV bands and for 336,633; 137,739; and 253,271 stars in the UVOT/uvw1, uvm2, and uvw2 bands, constructing corresponding ultraviolet extinction maps. Notably, the color excess data for the GALEX/near-UV band show a tenfold increase from previous results, with the extinction map covering approximately two-thirds of the sky at a resolution of 0 .° 4. The typical uncertainties in the ultraviolet color excesses are 0.21 mag, 0.30 mag, 0.19 mag, 0.24 mag, and 0.21 mag for  ENUV,GRP ,  EFUV,GRP ,  Euvw1,GRP ,  Euvm2,GRP , and  Euvw2,GRP , respectively. By comparing the spatial distributions of RV derived from ultraviolet and Gaia optical band measurements with those obtained from infrared and optical data in previous works, it is evident that the RV distributions based on the ultraviolet data show noticeable differences, with some regions even exhibiting opposite trends. This suggests that a single-parameter RV extinction law may not be sufficient to simultaneously characterize the extinction behavior across infrared, optical, and ultraviolet bands.

Keywords: Interstellar dust, Ultraviolet extinction
Dual-coding Contrastive Learning Based on the ConvNeXt and ViT Models for Morphological Classification of Galaxies in COSMOS-Web. In our previous works, we proposed a machine learning framework named USmorph for efficiently classifying galaxy morphology. In this study, we propose a self-supervised method called contrastive learning to upgrade the unsupervised machine learning (UML) part of the USmorph framework, aiming to improve the efficiency of feature extraction in this step. The upgraded UML method primarily consists of the following three aspects. (1) We employ a convolutional autoencoder to denoise galaxy images and adaptive polar coordinate transformation to enhance the model's rotational invariance. (2) A pretrained dual-encoder convolutional neural network based on ConvNeXt and a vision transformer is used to encode the image data, while contrastive learning is then applied to reduce the dimension of the features. (3) We adopt a bagging-based clustering model to cluster galaxies with similar features into distinct groups. By carefully dividing the redshift bins, we apply this model to the rest-frame optical images of galaxies in the COSMOS-Web field within the redshift range of 0.5 &lt; z &lt; 6.0. Compared to the previous algorithm, the improved UML method successfully classifies 73% of galaxies. Using the GoogLeNet algorithm, we classify the morphology of the remaining 27% of galaxies. To validate the reliability of our updated algorithm, we compared our classification results with other galaxy morphological parameters and found a good consistency with galaxy evolution. Benefiting from its higher efficiency, this updated algorithm is well suited for application in future China Space Station Telescope missions.

Keywords: Astrostatistics techniques, Galaxy structure, Astronomy data analysis
Evolution of Solar Wind Turbulence during Radial Alignment of Parker Solar Probe and Solar Orbiter in 2022 December. We investigate the radial evolution of solar wind turbulence during the radial alignment of Parker Solar Probe (PSP) and Solar Orbiter (SO) on 2022 December 10, with PSP located at approximately 0.11 au and SO near 0.88 au. To identify nearly the same plasma parcel crossing both spacecraft, we apply a ballistic propagation model with time-constant acceleration constrained by in situ solar wind velocity measurements at PSP and SO. We trace the magnetic footpoint of the plasma parcel back to the photosphere using a potential field source surface model based on a Global Oscillations Network Group synoptic magnetogram. Field and plasma measurements from PSP and SO are used to analyze power spectral density (PSD), spectral scaling, magnetic compressibility, and intermittency. Our results show that (1) the trace PSD of magnetic fluctuations steepens in the inertial range and flattens in the dissipation range with increasing radial distance; (2) the spectral break shifts to lower frequencies at SO; and (3) the Castaing model reveals multifractal intermittency in the inertial range, with slightly weaker intermittency at SO. These findings based on the same plasma parcel are consistent with the results of statistical studies on the radial evolution of turbulence and provide a reference for theoretical modeling of turbulence in the inner heliosphere.

Keywords: Interplanetary turbulence, Solar wind
SpecTE: Parameter Estimation for LAMOST Low-resolution Stellar Spectra Based on Denoising Pretraining. This paper proposes a spectral transformer encoder (SpecTE) model based on a denoising pretraining technique, and applies it to estimating radial velocity (RV) and three stellar atmospheric physical parameters together with 15 chemical element abundances from low-resolution spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). SpecTE enhances its sensitivity to spectral features and improves its parameter estimation accuracy by prelearning a mapping from low-quality spectra to high-quality spectra. We systematically evaluate the performance of SpecTE on the test set. On the cases with a signal-to-noise ratio of g ≥ 5, SpecTE achieved mean absolute error of 45 K for Teff, 0.08 dex for  logg , 0.037–0.05 dex for Fe, Mg, Si, Ni, Ca, and C, 0.05–0.077 dex for Al, Mn, O, S, and K, 0.09–0.12 dex for Ti, N, and Cr, 0.15 dex for V, 0.21 dex for Na, and 3.87 km s‑1 for RV, respectively. Compared with StarNet, StarGRUNet, and SHBoost, SpecTE demonstrates significant advantages in both estimation accuracy and precision. Nevertheless, SpecTE also exhibits certain limitations, including relatively lower accuracy in the abundances of Na, V, and Cr. In addition, it shows some systematic biases when applied to metal-poor stars and stars with extreme elemental abundances. Finally, we estimated the parameters and their uncertainties for 9.80 million LAMOST DR11 low-resolution spectra, thereby compiling the LAMOST-SpecTE catalog. Compared with the DD-Payne and StarGRUNet catalogs, LAMOST-SpecTE exhibits higher accuracy and robustness. The computed catalog demonstrates good consistency with APOGEE and GALAH. The estimated stellar catalog, code, pretrained model, and experimental data are released online for astronomical exploration and algorithm research.

Keywords: Astronomy databases
Frequency-comb-calibrated Laser Heterodyne Radiometry for Precision Radial Velocity Measurements. Disk-integrated observations of the Sun provide a unique vantage point to explore stellar activity and its effect on measured radial velocities. Here we report a new approach for disk-integrated solar spectroscopy and evaluate its capabilities for solar radial velocity measurements. Our approach is based on a near-infrared laser heterodyne radiometer (LHR) combined with an optical frequency comb calibration, and we show that this combination enables precision, disk-integrated solar spectroscopy with high spectral resolution (∼800,000), high signal-to-noise ratio (∼2600), and absolute frequency accuracy. We use the comb-calibrated LHR to record spectra of the solar Fe I 1565 nm transition over a 6-week period. We show that our measurements reach sub-meter-per-second radial velocity precision over a single day, and we use daily measurements of the absolute line center to assess the long-term stability of the comb-calibrated LHR approach. We use this long-duration data set to quantify the principal uncertainty sources that impact the measured radial velocities, and we discuss future modifications that can further improve this approach in studies of stellar variability and its impact on radial velocity measurements.

Keywords: Solar activity, Radial velocity, Solar instruments
Monitoring AGNs with Hβ Asymmetry. V. Long-term Variation and Evolution of the Broad Hβ Emission-line Profiles. The physical origins of the diverse emission-line asymmetries observed in the spectra of active galactic nuclei (AGNs) are not completely understood. Monitoring the temporal variations of line profiles offers a promising approach to investigating the underlying physics. In this study, we present an analysis of the broad Hβ emission line profiles of eight AGNs observed from 2016–2023 May as part of the reverberation mapping campaign titled "Monitoring AGNs with Hβ Asymmetry," utilizing data obtained from the Wyoming Infrared Observatory 2.3 m telescope. We measure the temporal variations of line asymmetry, width, and central velocity shift for the eight objects. Our findings reveal that the variation in asymmetry is positively correlated with Hβ flux in five of the eight objects, while the remaining objects exhibit negative or complex correlations. Furthermore, we observe anticorrelations between line width and Hβ flux for most objects, indicating the presence of the "breathing" phenomenon in their Hβ emission lines. In contrast, two objects demonstrate an "anti-breathing" phenomenon or complex behavior. We discuss the physical origins of the temporal variations in line profiles and propose the possibility of decomposing the variations in Hβ asymmetry and width into components: one that corresponds to short-term variations in Hβ flux and another that reflects long-term variations in continuum light curves, perhaps driven by radiation pressure.

Keywords: Supermassive black holes, Quasars, Reverberation mapping, Active galaxies, Active galactic nuclei
Absolute Rate Coefficients for Dielectronic Recombination of Sodium-like Iron Ions: Experiment and Theory. Absolute dielectronic recombination (DR) rate coefficients for sodium-like Fe15+ forming magnesium-like Fe14+ have been measured using the electron–ion merged-beams technique at the heavy ion storage ring Main Cooler Storage Ring, Lanzhou. The measured DR rate coefficients in the energy range from 0 to 90 eV cover all of the DR resonances due to 3s → 3p and 3s → 3d (Δn = 0) transitions and part of the DR resonances from 3s → 4ℓ (Δn = 1) core excitation. The experimental results are compared with theoretical calculations by using three independent state-of-the-art perturbative techniques: a multiconfiguration Breit–Pauli method using the AUTOSTRUCTURE code, a relativistic configuration interaction method using the Flexible Atomic Code and a multiconfiguration Dirac–Fock method using the Jena Atomic Calculator codes. Our theoretical results show excellent agreement with the experimental data in the energy range of 0–40 eV. However, in the energy range of 40–90 eV, a discrepancy is observed between the experiment and theory. Furthermore, temperature-dependent plasma recombination rate coefficients are derived from the measured DR rate coefficients over the temperature range of 103–108 K and are compared with previously available results in the literature. Within the temperature ranges relevant to photoionized plasmas and collisionally ionized plasmas, our results show good agreement with the experimental result from S. Schippers et al. (2010), as well as with the theoretical data of M. F. Gu (2004) and Z. Altun et al.; however, the earlier theoretical data from M. Arnaud &amp; J. Raymond and P. Mazzotta et al., which are based on LS-coupling calculations, significantly underestimate the plasma rate coefficients in the low-temperature range. The present results provide a benchmark data set for astrophysical modeling.

Keywords: Laboratory astrophysics, Dielectronic recombination, Atomic data benchmarking