Sazuna/UAT_keywords huggingface dataset:
Ubiquitous Molecular Outflows in z &gt; 4 Massive, Dusty Galaxies. II. Momentum-driven Winds Powered by Star Formation in the Early Universe. Galactic outflows of molecular gas are a common occurrence in galaxies and may represent a mechanism by which galaxies self-regulate their growth, redistributing gas that could otherwise have formed stars. We previously presented the first survey of molecular outflows at z &gt; 4 toward a sample of massive, dusty galaxies. Here we characterize the physical properties of the molecular outflows discovered in our survey. Using low-redshift outflows as a training set, we find agreement at the factor of 2 level between several outflow rate estimates. We find molecular outflow rates of 150-800 ${M}_{\odot }$ yr-1 and infer mass loading factors just below unity. Among the high-redshift sources, the molecular mass loading factor shows no strong correlations with any other measured quantity. The outflow energetics are consistent with expectations for momentum-driven winds with star formation as the driving source, with no need for energy-conserving phases. There is no evidence for active galactic nucleus activity in our sample, and while we cannot rule out deeply buried active galactic nuclei, their presence is not required to explain the outflow energetics, in contrast to nearby obscured galaxies with fast outflows. The fraction of the outflowing gas that will escape into the circumgalactic medium (CGM), though highly uncertain, may be as high as 50%. This nevertheless constitutes only a small fraction of the total cool CGM mass based on a comparison to z ∼ 2-3 quasar absorption line studies, but could represent ≳10% of the CGM metal mass. Our survey offers the first statistical characterization of molecular outflow properties in the very early universe.

Keywords: Gravitational lensing, Galactic winds, High-redshift galaxies, Galaxy evolution
Probing Jet Launching in Neutron Star X-Ray Binaries: The Variable and Polarized Jet of SAX J1808.4-3658. We report on an optical photometric and polarimetric campaign on the accreting millisecond X-ray pulsar (AMXP) SAX J1808.4-3658 during its 2019 outburst. The emergence of a low-frequency excess in the spectral energy distribution in the form of a red excess above the disk spectrum (seen most prominently in the z, i, and R bands) is observed as the outburst evolves. This is indicative of optically thin synchrotron emission due to a jet, as seen previously in this source and in other AMXPs during outburst. At the end of the outburst decay, the source enters a reflaring state. The low-frequency excess is still observed during the reflares. Our optical (BVRI) polarimetric campaign shows variable linear polarization (LP) throughout the outburst. We show that this is intrinsic to the source, with low-level but significant detections (0.2%-2%) in all bands. The LP spectrum is red during both the main outburst and the reflaring state, favoring a jet origin for this variable polarization over other interpretations, such as Thomson scattering with free electrons from the disk or the propelled matter. During the reflaring state, a few episodes with stronger LP levels (1%-2%) are observed. The low-level, variable LP is suggestive of strongly tangled magnetic fields near the base of the jet. These results clearly demonstrate how polarimetry is a powerful tool for probing the magnetic field structure in X-ray binary jets, as for active galactic nuclei jets.

Keywords: Neutron stars, Stellar accretion disks, Jets, Compact objects, Low-mass x-ray binary stars
Surface Energy of the Titan Aerosol Analog "Tholin". The photochemical haze produced in the upper atmosphere of Titan plays a key role in various atmospheric and surface processes on Titan. The surface energy, one important physical property of the haze, is crucial for understanding the growth of the haze particles and can be used to predict their wetting behavior with solid and liquid species on Titan. We produced Titan analog haze materials, so-called "tholins," with different energy sources and measured their surface energies through contact angle and direct force measurements. From the contact angle measurement, we found that the tholins produced by cold plasma and UV irradiation have a total surface energy around 60-70 mJ m-2. The direct force measurement yields a total surface energy of ∼66 mJ m-2 for plasma tholin. The surface energy of tholin is relatively high compared to common polymers, indicating its high cohesiveness. Therefore, the Titan haze particles would likely coagulate easily to form bigger particles, while the haze-derived surface sand particles would need a higher wind speed to be mobilized because of the high interparticle cohesion. The high surface energy of tholins also makes them easily wettable by Titan's atmospheric hydrocarbon condensates and surface liquids. Thus, the haze particles are likely good cloud condensation nuclei for hydrocarbon clouds (methane and ethane) to nucleate and grow. And if the haze particles are denser compared to the lake liquids, they will likely sink into the lakes instead of forming a floating film to dampen the lake surface waves.

Keywords: Surface processes, Planetary atmospheres, Surface composition, Saturnian satellites
Kinematical Signs of Dust Trapping and Feedback in a Local Pressure Bump in the Protoplanetary Disk around HD 142527 Revealed with ALMA. We analyzed the archival data of the continuum emission at six wavelengths from 3 to 0.4 mm and 13CO and C18O (1-0, 2-1, and 3-2) lines in the protoplanetary disk around HD 142527 obtained with the Atacama Large Millimeter/submillimeter Array. We performed fitting to the spectral energy distributions obtained at the six wavelengths with the graybody slab models to estimate the distributions of the dust surface density and spectral index of dust absorption coefficient β. We also estimated the distribution of the gas column density by fitting the C18O spectra and measured the disk rotation by fitting the Keplerian disk models to the C18O data. We found super- and sub-Keplerian rotation inside and outside the dust ring in the northwest in the HD 142527 disk, suggestive of the presence of a local pressure bump. In comparison with our estimated dust and gas distributions, the location of the pressure bump is coincident with the region showing a three times higher dust density and a three times lower gas-to-dust mass ratio than the mean values in the disk, suggesting dust trapping in the pressure bump. Nevertheless, there is no correlation between our derived β distribution and the location of the pressure bump. In addition, we found that the width of the dust ring is comparable to or larger than the width of the pressure bump, which could suggest that dust feedback is significant in the pressure bump.

Keywords: Gas-to-dust ratio, Dust continuum emission, Protoplanetary disks, CO line emission, Planet formation
Formation of Smaller Anions from C<SUB>n</SUB>N<SUP>-</SUP> (n = 1-3, 5-7) in the Circumstellar Medium. We probe a new pathway for the formation of smaller anions from the temporary negative ion states (anion resonances) of CnN- (n = 1-3, 5-7) in the circumstellar envelope of IRC+10216. CnN- (n = 1-3, 5-7) anions were collisionally excited to their resonance states and were observed to decay into a variety of smaller anions. The measured kinetic-energy-release distributions for the anionic fragments arising from each of the parent anions indicate a concerted manner of occurrence of these fragments, implying rich dissociation dynamics. ${{\rm{C}}}_{2}^{-}$ and C2N- were found to be dominant fragments of these anions, suggesting their presence in the external layers of IRC+10216 where UV photons penetrate. CnN- (n = 1-3) were also observed to undergo dissociative and nondissociative double-electron detachments, with the former being dominant. The significance of this new pathway in determining the stability and abundance of anions in IRC+10216 is discussed.

Keywords: Interstellar molecules, Interstellar dynamics, Interstellar abundances, Astrochemistry, Astrophysical processes
A HaloSat Analysis of the Cygnus Superbubble. The Cygnus Superbubble (CSB) is a region of soft X-ray emission approximately 13 degrees wide in the direction of the local spiral arm. Such a large region might be the result of strong stellar winds and supernovae from nearby stellar nurseries, or it could be the result of a single event—a hypernova. HaloSat observed four nonoverlapping 10 degree diameter fields in the CSB region over the 0.4-7 keV band. The CSB absorption and temperature was found to be consistent over all four fields, with a weighted average of 6.1 × 1021 cm-2 and 0.190 keV, respectively. These observations suggest that the CSB is a cohesive object with a singular origin. The total thermal energy for the CSB is estimated at 4 × 1052 erg, based upon a shell-like physical model of the CSB. Absorption and distance estimates to Cyg OB associations are examined. The CSB absorption is found to be most consistent with the absorption seen in Cyg OB1, implying that the CSB lies at a similar distance of 1.1-1.4 kpc.

Keywords: Supernova remnants, OB associations, X-ray astronomy, Hypernovae
Biconical-dominated Accretion Flow onto Seed Black Holes in a Hyperaccretion Regime. Hyperaccretion occurs when the gas inflow rate onto a black hole (BH) is so high that the radiative feedback cannot reverse the accretion flow. This extreme process is a promising mechanism for the rapid growth of seed BHs in the early universe, which can explain high-redshift quasars powered by billion solar mass BHs. In theoretical models, spherical symmetry is commonly adopted for hyperaccretion flows; however, the sustainability of such structures on timescales corresponding to the BH growth has not been addressed yet. Here we show that stochastic interactions between the ionizing radiation from the BH and nonuniform accretion flow can lead to the formation of a rotating gas disk around the BH. Once the disk forms, the supply of gas to the BH preferentially occurs via biconical-dominated accretion flow perpendicular to the disk, avoiding the centrifugal barrier of the disk. Biconical dominated accretion flows from opposite directions collide in the vicinity of the BH supplying high-density, low angular momentum gas to the BH, whereas most of the gas with nonnegligible angular momentum is deflected to the rotationally supported outflowing decretion disk. The disk becomes reinforced progressively as more mass from the biconical flow transfers to the disk and some of the outflowing gas from the disk is redirected to the biconical accretion funnels through a meridional structure. This axisymmetric hydrodynamic structure of a biconical-dominated accretion flow and decretion disk continues to provide uninterrupted flow of high-density gas to the BH.

Keywords: Accretion, Black hole physics, Hydrodynamical simulations, Hydrodynamics, Radiative transfer, Radiative transfer simulations
Photometric Classification of 2315 Pan-STARRS1 Supernovae with Superphot. The classification of supernovae (SNe) and its impact on our understanding of explosion physics and progenitors have traditionally been based on the presence or absence of certain spectral features. However, current and upcoming wide-field time-domain surveys have increased the transient discovery rate far beyond our capacity to obtain even a single spectrum of each new event. We must therefore rely heavily on photometric classification—connecting SN light curves back to their spectroscopically defined classes. Here, we present Superphot, an open-source Python implementation of the machine-learning classification algorithm of Villar et al., and apply it to 2315 previously unclassified transients from the Pan-STARRS1 Medium Deep Survey for which we obtained spectroscopic host-galaxy redshifts. Our classifier achieves an overall accuracy of 82%, with completenesses and purities of &gt;80% for the best classes (SNe Ia and superluminous SNe). For the worst performing SN class (SNe Ibc), the completeness and purity fall to 37% and 21%, respectively. Our classifier provides 1257 newly classified SNe Ia, 521 SNe II, 298 SNe Ibc, 181 SNe IIn, and 58 SLSNe. These are among the largest uniformly observed samples of SNe available in the literature and will enable a wide range of statistical studies of each class.

Keywords: Light curve classification , Supernovae, Astrostatistics
SuperRAENN: A Semisupervised Supernova Photometric Classification Pipeline Trained on Pan-STARRS1 Medium-Deep Survey Supernovae. Automated classification of supernovae (SNe) based on optical photometric light-curve information is essential in the upcoming era of wide-field time domain surveys, such as the Legacy Survey of Space and Time (LSST) conducted by the Rubin Observatory. Photometric classification can enable real-time identification of interesting events for extended multiwavelength follow-up, as well as archival population studies. Here we present the complete sample of 5243 "SN-like" light curves (in gP1rP1iP1zP1) from the Pan-STARRS1 Medium-Deep Survey (PS1-MDS). The PS1-MDS is similar to the planned LSST Wide-Fast-Deep survey in terms of cadence, filters, and depth, making this a useful training set for the community. Using this data set, we train a novel semisupervised machine learning algorithm to photometrically classify 2315 new SN-like light curves with host galaxy spectroscopic redshifts. Our algorithm consists of an RF supervised classification step and a novel unsupervised step in which we introduce a recurrent autoencoder neural network (RAENN). Our final pipeline, dubbed SuperRAENN, has an accuracy of 87% across five SN classes (Type Ia, Ibc, II, IIn, SLSN-I) and macro-averaged purity and completeness of 66% and 69%, respectively. We find the highest accuracy rates for SNe Ia and SLSNe and the lowest for SNe Ibc. Our complete spectroscopically and photometrically classified samples break down into 62.0% Type Ia (1839 objects), 19.8% Type II (553 objects), 4.8% Type IIn (136 objects), 11.7% Type Ibc (291 objects), and 1.6% Type I SLSNe (54 objects).

Keywords: Light curve classification , Supernovae, Astrostatistics
Bimodal Behavior and Convergence Requirement in Macroscopic Properties of the Multiphase Interstellar Medium Formed by Atomic Converging Flows. We systematically perform hydrodynamics simulations of 20 $\mathrm{km}\,{{\rm{s}}}^{-1}$ converging flows of the warm neutral medium (WNM) to calculate the formation of the cold neutral medium (CNM), focusing especially on the mean properties of the multiphase interstellar medium (ISM), such as the mean density on a 10 pc scale. Our results show that convergence in those mean properties requires a 0.02 pc spatial resolution that resolves the cooling length of the thermally unstable neutral medium (UNM) to follow the dynamical condensation from the WNM to the CNM. We also find that two distinct postshock states appear in the mean properties depending on the amplitude of the upstream WNM density fluctuation ${\rm{\Delta }}{\rho }_{0}$ ( $=\,\sqrt{\langle \delta {\rho }_{0}^{2}\rangle }{/\rho }_{0}$ ). When ${\rm{\Delta }}{\rho }_{0}\gt 10 \% $ , the interaction between shocks and density inhomogeneity leads to a strong driving of the postshock turbulence of &gt;3 km s-1, which dominates the energy budget in the shock-compressed layer. The turbulence prevents dynamical condensation by cooling, and the CNM mass fraction remains at ∼45%. In contrast, when ${\rm{\Delta }}{\rho }_{0}\leqslant 10 \% $ , the CNM formation proceeds efficiently, resulting in the CNM mass fraction of ∼70%. The velocity dispersion is limited to the thermal-instability-mediated level of ∼2-3 km s-1, and the layer is supported by both turbulent and thermal energy equally. We also propose an effective equation of state that models the multiphase ISM formed by the WNM converging flow as a one-phase ISM in the form of P ∝ ργeff, where γeff varies from 0.9 (for a large pre-shock Δρ0) to 0.7 (for a small pre-shock Δρ0).

Keywords: Warm neutral medium, Cold neutral medium, Interstellar dynamics, Interstellar medium
Why Interstellar Ice Dust Grains Should Be Elongated. Models of interstellar dust alignment assume that dust grains are elongated, but none of these models explain why dust grains should be elongated. On the other hand, models of interstellar dust grain growth assume that dust grains are spherical and not elongated. We show that when dusty plasma effects and the dipole moment of water molecules are together taken into account, ice grains in interstellar space should be prolate ellipsoids and not spheres. Dusty plasma analysis shows that an ice grain is charged to a negative potential that has magnitude nearly equal to that of the electron temperature. Several different mechanisms causing deviation from sphericity are identified; these mechanisms involve the interaction of the dipole moment of water molecules with electric fields associated with ice grain charging. These mechanisms include the focusing of water molecule trajectories, the migration of water molecules in a quasi-liquid layer on the grain surface toward regions where the electric field is strongest, the enhancement of this migration by the bombardment of energetic protons that gain energy upon falling into the ice grain negative potential, and mutual repulsion by electric charges having the same sign. The aspect ratio is established shortly after the ice grain is formed, and then is maintained as the grain grows.

Keywords: Interstellar molecules, Water vapor, Ice formation, Very small grains, Laboratory astrophysics, Plasma astrophysics, Interstellar magnetic fields, Interstellar emissions, Starlight polarization, Interstellar dust processes
Powerful t-SNE Technique Leading to Clear Separation of Type-2 AGN and H II Galaxies in BPT Diagrams. Narrow emission-line galaxies can be distinguished in the well-known BPT diagrams through narrow emission-line properties. However, there are no boundaries visible to the naked eye between type-2 active galactic nuclei (AGN) and H II galaxies in BPT diagrams, besides the extreme dividing lines expected by theoretical photoionization models. Here, based on the powerful t-SNE technique applied to the local narrow emission-line galaxies in the Sloan Digital Sky Survey Data Release 15, type-2 AGN and H II galaxies can be clearly separated in the t-SNE determined two-dimensional projected map, and then the dividing lines can be mathematically determined in BPT diagrams, leading to charming harmonization of the theoretical expectations and the actual results from real observed properties. The results not only provide an interesting and robust method to determine the dividing lines in BPT diagrams through the powerful t-SNE technique, but also lead to further confirmation on previously defined composite galaxies more efficiently classified in the BPT diagram of [O III]/Hβ versus [N II]/Hα.

Keywords: Active galactic nuclei, H II regions, Emission line galaxies
ZTF20aajnksq (AT 2020blt): A Fast Optical Transient at z ≍ 2.9 with No Detected Gamma-Ray Burst Counterpart. We present ZTF20aajnksq (AT 2020blt), a fast-fading (∆r = 2.3 mag in ∆t = 1.3 days) red (g - r ≍ 0.6 mag) and luminous (M1626 Å = -25.9 mag) optical transient at z = 2.9 discovered by the Zwicky Transient Facility (ZTF). AT 2020blt shares several features in common with afterglows to long-duration gamma-ray bursts (GRBs): (1) an optical light curve well-described by a broken power law with a break at tj = 1 d (observer frame); (2) a luminous (L0.3-10 KeV = 1046 erg s-1) X-ray counterpart; and (3) luminous (L10 GHz = 4 × 1031 erg s-1 Hz-1) radio emission. However, no GRB was detected in the 0.74 days between the last ZTF nondetection (r &gt; 21.36 mag) and the first ZTF detection (r = 19.60 mag), with an upper limit on the isotropic-equivalent gamma-ray energy release of Eγ,iso &lt; 7 × 1052 erg. AT 2020blt is thus the third afterglow-like transient discovered without a detected GRB counterpart (after PTF11agg and ZTF19abvizsw) and the second (after ZTF19abvizsw) with a redshift measurement. We conclude that the properties of AT 2020blt are consistent with a classical (initial Lorentz factor Γ0 ≳ 100) on-axis GRB that was missed by high-energy satellites. Furthermore, by estimating the rate of transients with light curves similar to that of AT 2020blt in ZTF high-cadence data, we agree with previous results that there is no evidence for an afterglow-like phenomenon that is significantly more common than classical GRBs, such as dirty fireballs. We conclude by discussing the status and future of fast-transient searches in wide-field high-cadence optical surveys.

Keywords: Gamma-ray bursts, Sky surveys, Surveys, Transient sources, X-ray transient sources, Radio transient sources
Revisiting the Distance, Environment, and Supernova Properties of SNR G57.2+0.8 that Hosts SGR 1935+2154. We have performed a multiwavelength study of supernova remnant (SNR) G57.2+0.8 and its environment. The SNR hosts the magnetar SGR 1935+2154, which emitted an extremely bright millisecond-duration radio burst on 2020 April 28. We used the 12CO and 13CO J = 1-0 data from the Milky Way Image Scroll Painting CO line survey to search for molecular gas associated with G57.2+0.8, in order to constrain the physical parameters (e.g., the distance) of the SNR and its magnetar. We report that SNR G57.2+0.8 is likely impacting the molecular clouds (MCs) at the local standard of rest (LSR) velocity ${V}_{\mathrm{LSR}}\sim 30\,\mathrm{km}\,{{\rm{s}}}^{-1}$ and excites a weak 1720 MHz OH maser with a peak flux density of 47 mJy beam-1. The chance coincidence of a random OH spot falling in the SNR is ≤12%, and the OH-CO correspondence chance is 7% at the maser spot. This combines to give &lt;1% false probability of the OH maser, suggesting a real maser detection. The LSR velocity of the MCs places the SNR and magnetar at a kinematic distance of 6.6 ± 0.7 kpc. The nondetection of thermal X-ray emission from the SNR and the relatively dense environment suggests G57.2+0.8 be an evolved SNR with an age $t\gtrsim 1.6\times {10}^{4}(d/6.6\,\,\mathrm{kpc})\,\,\mathrm{yr}$ . The explosion energy of G57.2+0.8 is lower than $2\times {10}^{51}{({n}_{0}/10{\mathrm{cm}}^{-3})}^{1.16}{(d/6.6\mathrm{kpc})}^{3.16}\,\mathrm{erg}$ , which is not very energetic even assuming a high ambient density ${n}_{0}=10\,\,{\mathrm{cm}}^{-3}$ . This reinforces the opinion that magnetars do not necessarily result from very energetic supernova explosions.

Keywords: Molecular clouds, Supernova remnants, Soft gamma-ray repeaters, Magnetars, X-ray bursts, Radio transient sources
Is NGC 5824 the Core of the Progenitor of the Cetus Stream?. The complicated story of the Cetus Stream (CS) is recently revealed by its newly discovered ∼150 members with 6D kinematics from the cross-matched catalog of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 K giants and Gaia DR2. It exhibits a very diffuse structure at heliocentric distances between 20 and 50 kpc, extending over at least 100°, and crossing the Galactic plane. Interestingly, The CS is dynamically linked to a massive globular cluster, NGC 5824. A suggestive scenario is that NGC 5824 was the nuclear star cluster of the dwarf progenitor of the CS. We explore this scenario by modeling the disruption process of a dwarf galaxy in the Milky Way potential, on the orbit of NGC 5824, using a suite of N-body simulations. Our results show that the simulated stream can marginally recover the main component of the CS, which is the densest part of the observed stream. Inspired by this mismatch, we use a dwarf progenitor following the representative orbit of the main component members, and find it can reproduce the general morphology of the CS. This gives us a more favorable scenario of the CS progenitor, in which NGC 5824 was not the core, but located off-center. Our fiducial model also predicts a vast extension of the CS in the South, surprisingly coincident with a newly discovered wide southern stream "Palca." Another more diffuse substructure, the Eridanus-Phoenix overdensity is also likely to be related to the CS progenitor.

Keywords: Milky Way Galaxy, N-body simulations