Sazuna/UAT_keywords huggingface dataset:
The Nebular Properties of Star-forming Galaxies at Intermediate Redshift from the Large Early Galaxy Astrophysics Census. We present a detailed study of the partial rest-optical (λ obs ≍ 3600-5600 Å) spectra of N = 767 star-forming galaxies at 0.6 &lt; z &lt; 1.0 from the Large Early Galaxy Astrophysics Census (LEGA-C). We compare this sample with low-redshift (z ~ 0) galaxies from the Sloan Digital Sky Survey (SDSS), intermediate-redshift (z ~ 1.6) galaxies from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS Survey, and high-redshift (z ~ 2) galaxies from the Keck Baryonic Structure Survey (KBSS). At a look-back time of 6-8 Gyr, galaxies with stellar masses $\mathrm{log}({M}_{* }/{M}_{\odot })\gt 10.50$ appear remarkably similar to z ~ 0 galaxies in terms of their nebular excitation, as measured using [O III] λ5008/Hβ. There is some evidence that 0.6 &lt; z &lt; 1.0 galaxies with lower M * have higher [O III] λ5008/Hβ than z ~ 0 galaxies and are more similar to less evolved z ~ 1.6 and z ~ 2 galaxies, which are offset from the z ~ 0 locus at all M *. We explore the impact of selection effects, contributions from active galactic nuclei, and variations in physical conditions (ionization parameter and gas-phase oxygen abundance) on the apparent distribution of [O III] λ5008/Hβ and find somewhat higher ionization in 0.6 &lt; z &lt; 1.0 galaxies with lower M * relative to z ~ 0 galaxies. We use new near-infrared spectroscopic observations of a subsample of LEGA-C galaxies to investigate other probes of enrichment and excitation. Our analysis demonstrates the importance of obtaining complete rest-optical spectra of galaxies in order to disentangle these effects.

Keywords: Interstellar medium, Galaxy evolution, Galaxies
Modeling the Transport of Relativistic Solar Protons along a Heliospheric Current Sheet during Historic GLE Events. There are many difficulties associated with forecasting high-energy solar particle events at Earth. One issue is understanding why some large solar eruptive events trigger ground-level enhancement (GLE) events and others do not. In this work we perform 3D test particle simulations of a set of historic GLEs to understand more about what causes these powerful events. Particular focus is given to studying how the heliospheric current sheet (HCS) affects high-energy proton transport through the heliosphere following an event. Analysis of ≥M7.0 flares between 1976 and 2020 shows that active regions located closer to the HCS (&lt;10°) are more likely to be associated with a GLE event. We found that modeled GLE events where the source region was close to the HCS also led to increased heliospheric transport in longitude and higher count rates (when the Earth was located in the drift direction). In a model that does not include perpendicular diffusion associated with turbulence, the HCS is the dominant mechanism affecting heliospheric particle transport for GLE 42 and 69, and varying other parameters (e.g., a narrow, 10°, or wider, 60°, injection width) causes little change. Overall in our model, the HCS is relevant in 71% of our analyzed GLEs, and including it more accurately reproduces observed intensities near Earth. Our simulations enable us to produce model profiles at Earth that can be compared to existing observations by the GOES satellites and neutron monitors, as well as for use in developing future forecasting models.

Keywords: Heliosphere, Solar energetic particles, Space weather, Solar activity, Solar-terrestrial interactions
Eliminating Primary Beam Effect in Foreground Subtraction of Neutral Hydrogen Intensity Mapping Survey with Deep Learning. In neutral hydrogen (H I) intensity mapping (IM) survey, foreground contamination on cosmological signal is extremely severe, and systematic effects caused by radio telescopes further aggravate the difficulties in subtracting foreground. We investigate whether the deep-learning method, the 3D U-Net algorithm, can play a crucial role in foreground subtraction when considering the systematic effect caused by the telescope's primary beam. We consider two beam models, i.e., the Gaussian beam and Cosine beam models. The traditional principal component analysis (PCA) method is employed as a preprocessing step for the U-Net method to reduce the map dynamic range. We find that in the case of the Gaussian beam, the PCA method can effectively clean the foreground. However, the PCA method cannot handle the systematic effect induced by the Cosine beam, and the additional U-Net method can improve the result significantly. To show how well the PCA and U-Net methods can recover the H I signal, we also derive the H I angular power spectrum and H I 2D power spectrum after performing foreground subtraction. It is found that in the case of Gaussian beam, the concordance with the original H I map using U-Net is better than that using PCA by 27.4%, and in the case of Cosine beam, the concordance using U-Net is better than that using PCA by 144.8%. Therefore, the U-Net-based foreground subtraction can efficiently eliminate the telescope primary beam effect and shed new light on recovering H I power spectrum for future H I IM experiments.

Keywords: Sky surveys, Large-scale structure of the universe, Neural networks, Observational cosmology, H I line emission, Radio telescopes
Realistic Detection and Early Warning of Binary Neutron Stars with Decihertz Gravitational-wave Observatories. We investigated the detection rates and early-warning parameters of binary neutron star (BNS) populations with decihertz gravitational-wave observatories in a realistic detecting strategy. Assuming the operation time of B-DECIGO is 4 yr, we classified the detectable BNSs based on parameter precision into three categories: (a) sources that merge within 1 yr, which could be localized with an uncertainty of ΔΩ ~ 100 deg2; (b) sources that merge in 1-4 yr, which take up three-quarters of the total events and yield the most precise angular resolution with ΔΩ ~ 10-2 deg2 and time-of-merger accuracy with Δt  c  ~ 10-1 s; and (c) sources that do not merge during the 4 yr mission window, which enable possible early warnings, with ΔΩ ~ 10-1 deg2 and Δt  c  ~ 100 s. Furthermore, we compared the pros and cons of B-DECIGO with the third-generation ground-based detectors, and explored the prospects of detections using three other decihertz observatories and four BNS population models. In realistic observing scenarios, we found that decihertz detectors could even provide early-warning alerts to a source decades before its merger while their localizations are still as accurate as ground-based facilities. Finally we found a decrease of events when considering the confusion noise, but this could be partially solved by a proper noise subtraction.

Keywords: Gravitational wave astronomy, Neutron stars, Gravitational wave detectors
Search for Supernova Neutrinos and Constraint on the Galactic Star Formation Rate with the KamLAND Data. We present the results of a search for core-collapse supernova neutrinos, using long-term KamLAND data from 2002 March 9 to 2020 April 25. We focus on the electron antineutrinos emitted from supernovae in the energy range of 1.8-111 MeV. Supernovae will make a neutrino event cluster with the duration of ~10 s in the KamLAND data. We find no neutrino clusters and give the upper limit on the supernova rate to be 0.15 yr-1 with a 90% confidence level. The detectable range, which corresponds to a &gt;95% detection probability, is 40-59 kpc and 65-81 kpc for core-collapse supernovae and failed core-collapse supernovae, respectively. This paper proposes to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is &lt;(17.5-22.7) M ⊙ yr-1 with a 90% confidence level.

Keywords: Neutrino astronomy, Supernova neutrinos
A New Method to Constrain the Appearance and Disappearance of Observed Jellyfish Galaxy Tails. We present a new approach for observationally constraining where the tails of Jellyfish (JF) galaxies in groups and clusters first appear and how long they remain visible for with respect to the moment of their orbital pericenter. This is accomplished by measuring the distribution of their tail directions, with respect to their host centers, and their distribution in a projected velocity-radius phase-space diagram. We then model these observed distributions using a fast and flexible approach, where JF tails are painted onto dark matter halos, according to a simple parameterized prescription, before a Bayesian analysis is performed to estimate the parameters. We demonstrate the effectiveness of our approach using observational mocks, then apply it to a known observational sample of 106 JF galaxies, with radio-continuum tails located inside 68 hosts such as groups and clusters. We find that, typically, the radio-continuum tails become visible on first infall, when the galaxy reaches roughly three-quarters of r 200, and the tails remain visible for a few hundred Myr after pericenter passage. Lower-mass galaxies in more massive hosts tend to form visible tails further out and their tails disappear more quickly after pericenter. We argue that this indicates that they are more sensitive to ram pressure stripping. With upcoming large-area surveys of JF galaxies in progress, this is a promising new method for constraining the environmental conditions in which visible JF tails exist.

Keywords: Galaxy clusters, Galaxy dark matter halos, Orbits, Galaxy tails, Galaxy groups, Galaxy evolution, Radio continuum emission
A Massive, Dusty, HI Absorption-Selected Galaxy at z ≈ 2.46 Identified in a CO Emission Survey. We report a NOrthern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter/submillimeter Array search for redshifted CO emission from the galaxies associated with seven high-metallicity ([M/H] ≥ -1.03) damped Lyα absorbers (DLAs) at z ≈ 1.64-2.51. Our observations yielded one new detection of CO(3-2) emission from a galaxy at z = 2.4604 using NOEMA, associated with the z = 2.4628 DLA toward QSO B0201+365. Including previous searches, our search results in detection rates of CO emission of $\approx {56}_{-24}^{+38}$ % and $\approx {11}_{-9}^{+26}$ %, respectively, in the fields of DLAs with [M/H] &gt; -0.3 and [M/H] &lt; -0.3. Further, the HI-selected galaxies associated with five DLAs with [M/H] &gt; -0.3 all have high molecular gas masses, ≳5 × 1010 M ⊙. This indicates that the highest-metallicity DLAs at z ≈ 2 are associated with the most massive galaxies. The newly identified z ≈ 2.4604 HI-selected galaxy, DLA0201+365g, has an impact parameter of ≈7 kpc to the QSO sightline, and an implied molecular gas mass of (5.04 ± 0.78) × 1010 × (α CO/4.36) × (r 31/0.55) M ⊙. Archival Hubble Space Telescope Wide Field and Planetary Camera 2 imaging covering the rest-frame near-ultraviolet (NUV) and far-ultraviolet (FUV) emission from this galaxy yield nondetections of rest-frame NUV and FUV emission, and a 5σ upper limit of 2.3 M ⊙ yr-1 on the unobscured star formation rate (SFR). The low NUV-based SFR estimate, despite the very high molecular gas mass, indicates that DLA0201+365g either is a very dusty galaxy, or has a molecular gas depletion time that is around 2 orders of magnitude larger than that of star-forming galaxies at similar redshifts.

Keywords: Damped Lyman-alpha systems, High-redshift galaxies, CO line emission
Impact of Dust Size Distribution Including Large Dust Grains on Magnetic Resistivity: An Analytical Approach. This paper investigates the impact of dust size distribution on magnetic resistivity. In particular, we focus on its impact when the maximum dust size significantly increases from a submicron level. The first half of the paper describes our calculation method for magnetic resistivity based on the model of Draine &amp; Sutin and shows that the method reproduces the results of more realistic chemical reaction network calculations reasonably well. Then, we describe the results of the resistivity calculations for dust distributions with large maximum dust grains. Our results show that resistivity tends to decrease with dust growth, which is particularly true when the dust size power exponent q is q = 2.5. On the other hand, the decrease is less pronounced when the dust size power exponent q is q = 3.5, i.e., when the small dust is also responsible for the dust cross section. Our results suggest that detailed dust coagulation and fragmentation processes play a vital role in the magnetic resistivities in protostar formation.

Keywords: Protoplanetary disks, Circumstellar disks
Very Large Array Multiband Radio Imaging of the Triple AGN Candidate SDSS J0849+1114. Kiloparsec-scale triple active galactic nuclei (AGNs), potential precursors of gravitationally bound triple massive black holes (MBHs), are rarely seen objects and believed to play an important role in the evolution of MBHs and their host galaxies. In this work we present a multiband (3.0, 6.0, 10.0, and 15.0 GHz), high-resolution radio imaging of the triple AGN candidate, SDSS J0849+1114, using the Very Large Array. Two of the three nuclei (A and C) are detected at 3.0, 6.0, and 15 GHz for the first time, both exhibiting a steep spectrum over 3-15 GHz (with a spectral index -0.90 ± 0.05 and -1.03 ± 0.04) consistent with a synchrotron origin. Nucleus A, the strongest nucleus among the three, shows a double-sided jet, with the jet orientation changing by ~20° between its inner 1″ and the outer 5.″5 (8.1 kpc) components, which may be explained as the MBH's angular momentum having been altered by merger-enhanced accretion. Nucleus C also shows a two-sided jet, with the western jet inflating into a radio lobe with an extent of 1.″5 (2.2 kpc). The internal energy of the radio lobe is estimated to be 5.0 × 1055 erg, for an equipartition magnetic field strength of ~160 μG. No significant radio emission is detected at all four frequencies for nucleus B, yielding an upper limit of 15, 15, 15, and 18 μJy beam-1 at 3.0, 6.0, 10.0, and 15.0 GHz, based on which we constrain the star formation rate in nucleus B to be ≲0.4 M ⊙ yr-1.

Keywords: Radio continuum emission, Galaxy nuclei, Active galaxies, Galaxy interactions
Improving the Low-energy Transient Sensitivity of AMEGO-X using Single-site Events. AMEGO-X, the All-sky Medium Energy Gamma-ray Observatory eXplorer, is a proposed instrument designed to bridge the so-called "MeV gap" by surveying the sky with unprecedented sensitivity from ~100 keV to about 1 GeV. This energy band is of key importance for multimessenger and multiwavelength studies but it is nevertheless currently underexplored. AMEGO-X addresses this situation by proposing a design capable of detecting and imaging gamma rays via both Compton interactions and pair production processes. However, some of the objects that AMEGO-X will study, such as gamma-ray bursts and magnetars, extend to energies below ~100 keV where the dominant interaction becomes photoelectric absorption. These events deposit their energy in a single pixel of the detector. In this work we show how the ~3500 cm2 effective area of the AMEGO-X tracker to events between ~25 and ~100 keV will be utilized to significantly improve its sensitivity and expand the energy range for transient phenomena. Although imaging is not possible for single-site events, we show how we will localize a transient source in the sky using their aggregate signal to within a few degrees. This technique will more than double the number of cosmological gamma-ray bursts seen by AMEGO-X, allow us to detect and resolve the pulsating tails of extragalactic magnetar giant flares, and increase the number of detected less-energetic magnetar bursts-some possibly associated with fast radio bursts. Overall, single-site events will increase the sensitive energy range, expand the science program, and promptly alert the community of fainter transient events.

Keywords: Gamma-ray bursts, Gamma-ray detectors, Time domain astronomy, Magnetars, Gamma-ray astronomy
Slowly Cooling White Dwarfs in NGC 6752. Recently, a new class of white dwarfs ("slowly cooling WDs") has been identified in the globular cluster M13. The cooling time of these stars is increased by stable thermonuclear hydrogen burning in their residual envelope. These WDs are thought to be originated by horizontal branch (HB) stars populating the HB blue tail that skipped the asymptotic giant branch phase. To further explore this phenomenon, we took advantage of deep photometric data acquired with the Hubble Space Telescope in the near-ultraviolet and investigate the bright portion of the WD cooling sequence in NGC 6752, another Galactic globular cluster with a metallicity, age, and HB morphology similar to M13. The normalized WD luminosity function derived in NGC 6752 turns out to be impressively similar to that observed in M13, in agreement with the fact that the stellar mass distribution along the HB of these two systems is almost identical. As in the case of M13, the comparison with theoretical predictions is consistent with ~70% of the investigated WDs evolving at slower rates than standard, purely cooling WDs. Thanks to its relatively short distance from Earth, NGC 6752 photometry reaches a luminosity 1 order of a magnitude fainter than the case of M13, allowing us to sample a regime where the cooling time delay, with respect to standard WD models, reaches ~300 Myr. The results presented in this paper provide new evidence for the existence of slowly cooling WDs and further support to the scenario proposing a direct causal connection between this phenomenon and the HB morphology of the host stellar cluster.

Keywords: Globular star clusters, Hertzsprung Russell diagram, White dwarf stars, Ultraviolet photometry
Spectroscopic Diagnostics of the Mid-infrared Features of the Dark Globule DC 314.8-5.1 with the Spitzer Space Telescope. We present an analysis of the mid-infrared spectra, obtained from the Spitzer Space Telescope, of the dark globule DC 314.8-5.1, which is at the onset of low-mass star formation. The target has a serendipitous association with a B-type field star that illuminates a reflection nebula in the cloud. We focus on the polycyclic aromatic hydrocarbon (PAH) emission features prevalent throughout the mid-infrared range. The analysis of the spectra with the PAHFIT software as well as with the pypahdb package shows that (i) the intensities of PAH features decrease over distance from the ionizing star toward the cloud center, with some however showing a saturation at larger distances; (ii) the relative intensities of the 6.2 and 8.6 features with respect to the 11.2 μm feature remain high throughout the globule, suggesting a higher cation-to-neutral PAH ratio of the order of unity; the breakdown from pypahdb confirms a high ionized fraction within the cloud; (iii) the pypahdb results display a decrease in large-PAH fraction with increased distance from HD 130079, as well as a statistically significant correlation between the large-size fraction and the ionized fraction across the globule; (iv) the 7.7 PAH feature displays a peak nearer to 7.8 μm, suggesting a chemically processed PAH population with a small fraction of UV-processed PAHs; and (v) the H2 S(0) line is detected at larger distances from the ionizing star. All in all, our results suggest divergent physical conditions within the quiescent cloud DC 314.8-5.1 as compared to molecular clouds with ongoing star formation.

Keywords: Interstellar dust, Polycyclic aromatic hydrocarbons, Infrared dark clouds, Molecular clouds, Photodissociation regions, Interstellar medium
A VLA View of the Flared, Asymmetric Disk around the Class 0 Protostar L1527 IRS. We present high-resolution Karl G. Jansky Very Large Array (VLA) observations of the protostar L1527 IRS at 7 mm, 1.3 cm, and 2 cm wavelengths. We detect the edge-on dust disk at all three wavelengths and find that it is asymmetric, with the southern side of the disk brighter than the northern side. We confirm this asymmetry through analytic modeling and also find that the disk is flared at 7 mm. We test the data against models including gap features in the intensity profile, and though we cannot rule such models out, they do not provide a statistically significant improvement in the quality of fit to the data. From these fits, we can, however, place constraints on allowed properties of any gaps that could be present in the true, underlying intensity profile. The physical nature of the asymmetry is difficult to associate with physical features owing to the edge-on nature of the disk, but it could be related to spiral arms or asymmetries seen in other imaging of more face-on disks.

Keywords: Planetary system formation, Star formation, Protoplanetary disks, Protostars, Planet formation
SNIa Cosmology Analysis Results from Simulated LSST Images: From Difference Imaging to Constraints on Dark Energy. The Vera Rubin Observatory Legacy Survey of Space and Time (LSST) is expected to process ~106 transient detections per night. For precision measurements of cosmological parameters and rates, it is critical to understand the detection efficiency, magnitude limits, artifact contamination levels, and biases in the selection and photometry. Here we rigorously test the LSST Difference Image Analysis (DIA) pipeline using simulated images from the Rubin Observatory LSST Dark Energy Science Collaboration Data Challenge (DC2) simulation for the Wide-Fast-Deep survey area. DC2 is the first large-scale (300 deg2) image simulation of a transient survey that includes realistic cadence, variable observing conditions, and CCD image artifacts. We analyze ~15 deg2 of DC2 over a 5 yr time span in which artificial point sources from Type Ia supernova (SNIa) light curves have been overlaid onto the images. The magnitude limits per filter are u = 23.66 mag, g = 24.69 mag, r = 24.06 mag, i = 23.45 mag, z = 22.54 mag, and y = 21.62 mag. The artifact contamination levels are ~90% of all detections, corresponding to ~1000 artifacts deg-2 in g band, and falling to 300 deg-2 in y band. The photometry has biases &lt;1% for magnitudes 19.5 &lt; m &lt; 23. Our DIA performance on simulated images is similar to that of the Dark Energy Survey difference-imaging pipeline on real images. We also characterize DC2 image properties to produce catalog-level simulations needed for distance bias corrections. We find good agreement between DC2 data and simulations for distributions of signal-to-noise ratio, redshift, and fitted light-curve properties. Applying a realistic SNIa cosmology analysis for redshifts z &lt; 1, we recover the input cosmology parameters to within statistical uncertainties.

Keywords: Observational cosmology, Type Ia supernovae, Transient detection, Time domain astronomy, Dark energy