Sazuna/UAT_keywords huggingface dataset:
Electron-Ion Heating Partition in Imbalanced Solar-wind Turbulence. A likely candidate mechanism to heat the solar corona and solar wind is low-frequency "Alfvénic" turbulence sourced by magnetic fluctuations near the solar surface. Depending on its properties, such turbulence can heat different species via different mechanisms, and the comparison of theoretical predictions to observed temperatures, wind speeds, anisotropies, and their variation with heliocentric radius provides a sensitive test of this physics. Here we explore the importance of normalized cross helicity, or imbalance, for controlling solar-wind heating, since it is a key parameter of magnetized turbulence and varies systematically with wind speed and radius. Based on a hybrid-kinetic simulation in which the forcing's imbalance decreases with time-a crude model for a plasma parcel entrained in the outflowing wind-we demonstrate how significant changes to the turbulence and heating result from the "helicity barrier" effect. Its dissolution at low imbalance causes its characteristic features-strong perpendicular ion heating with a steep "transition-range" drop in electromagnetic fluctuation spectra-to disappear, driving a larger fraction of the energy into electrons and parallel ion heat, and halting the emission of ion-scale waves. These predictions seem to agree with a diverse array of solar-wind observations, offering to explain a variety of complex correlations and features within a single theoretical framework.

Keywords: Interplanetary turbulence, Solar wind, Plasma astrophysics
LIGO-Virgo-KAGRA's Oldest Black Holes: Probing Star Formation at Cosmic Noon With GWTC-3. In their third observing run, the LIGO-Virgo-KAGRA gravitational-wave (GW) observatory was sensitive to binary black hole (BBH) mergers out to redshifts z merge ≈ 1. Because GWs are inefficient at shrinking the binary orbit, some of these BBH systems likely experienced long delay times τ between the formation of their progenitor stars at z form and their GW merger at z merge. In fact, the distribution of delay times predicted by isolated binary evolution resembles a power law $p(\tau )\propto {\tau }^{{\alpha }_{\tau }}$ with slope -1 ≲ α  τ  ≲ -0.35 and a minimum delay time of ${\tau }_{\min }=10\,\mathrm{Myr}$ . We use these predicted delay time distributions to infer the formation redshifts of the ~70 BBH events reported in the third GW transient catalog GWTC-3 and the formation rate of BBH progenitors. For our default α  τ  = -1 delay time distribution, we find that GWTC-3 contains at least one system (with 90% credibility) that formed earlier than z form &gt; 4.4. Comparing our inferred BBH progenitor formation rate to the star formation rate, we find that at z form = 4, the number of BBH progenitor systems formed per stellar mass was ${6.4}_{-5.5}^{+9.4}\times {10}^{-6}\,{M}_{\odot }^{-1}$ and this yield dropped to ${0.134}_{-0.127}^{+1.6}\times {10}^{-6}\,{M}_{\odot }^{-1}$ by z form = 0. We discuss implications of this measurement for the cosmic metallicity evolution, finding that for typical assumptions about the metallicity dependence of the BBH yield, the average metallicity at z form = 4 was $\langle {\mathrm{log}}_{10}(Z/{Z}_{\odot })\rangle =-{0.3}_{-0.4}^{+0.3}$ , although the inferred metallicity can vary by a factor of ≈3 for different assumptions about the BBH yield. Our results highlight the promise of current GW observatories to probe high-redshift star formation.

Keywords: Massive stars, Stellar mass black holes, Gravitational wave astronomy, Star formation, Metallicity, Astrophysical black holes
Constraining the Jet Composition of GRB 221009A with the Prompt TeV Emission Limit. Recent LHAASO observations of the prompt emission phase of the brightest-of-all-time GRB 221009A imposes a stringent limit on the flux ratio between the TeV and MeV emissions, F TeV/F MeV ≤ 2 × 10-5, during the period 220-230 s after the trigger. This period covers the peak of the main MeV burst and is just before the TeV afterglow emerges. Within the framework of internal shocks, we study the internal γγ absorption in GRB 221009A by generating a set of synthetic bursts in a simulation that reproduces the observed feature of GRB 221009A. We find that the γγ absorption does not lead to an exponential cutoff, but rather a power-law spectrum, consistent with previous works. We further find that the attenuation due to γγ absorption alone cannot explain the flux limit ratio of GRB 221009A, suggesting a low ratio between synchrotron self-Compton (SSC) and synchrotron emission outputs. This requires the magnetic field energy density to be much larger than the synchrotron photon energy density so that the SSC flux is greatly suppressed. This indicates that the jet composition of GRB 221009A is likely Poynting flux dominated.

Keywords: Gamma-ray bursts, Non-thermal radiation sources, Radiative transfer, High energy astrophysics
Density Enhancement Streams in The Solar Wind. This Letter describes a new phenomenon on the Parker Solar Probe of recurring plasma density enhancements that have Δn/n ~ 10% and that occur at a repetition rate of ~5 Hz. They were observed sporadically for about 5 hr between 14 and 15 solar radii on Parker Solar Probe orbit 12 and they were also seen in the same radial range on both the inbound and outbound orbits 11. Their apparently steady-state existence suggests that their pressure gradient was balanced by the electric field. The X-component of the electric field component produced from this requirement is in good agreement with that measured. This provides strong evidence for the measurement accuracy of the density fluctuations and the X- and Y-components of the electric field (the Z-component was not measured). The electrostatic density waves were accompanied by an electromagnetic low-frequency wave, which occurred with the electrostatic harmonics. The amplitudes of these electrostatic and electromagnetic waves at ≥1 Hz were greater than the amplitude of the Alfvénic turbulence in their vicinity so they can be important for the heating, scattering, and acceleration of the plasma. The existence of this pair of waves is consistent with the observed plasma distributions and is explained as an oscilliton due to the nonlinear coupling between the kinetic Alfvén wave and the ion cyclotron mode, which belongs with the minor population of alpha particles.

Keywords: Solar coronal waves, Solar corona
UNCOVER: Illuminating the Early Universe-JWST/NIRSpec Confirmation of z &gt; 12 Galaxies. Observations of high-redshift galaxies provide a critical direct test to the theories of early galaxy formation, yet to date, only three have been spectroscopically confirmed at z &gt; 12. Due to strong gravitational lensing over a wide area, the galaxy cluster field A2744 is ideal for searching for the earliest galaxies. Here we present JWST/NIRSpec observations of two galaxies: a robust detection at ${z}_{\mathrm{spec}}={12.393}_{-0.001}^{+0.004}$ , and a plausible candidate at ${z}_{\mathrm{spec}}={13.079}_{-0.001}^{+0.013}$ . The galaxies are discovered in JWST/NIRCam imaging and their distances are inferred with JWST/NIRSpec spectroscopy, all from the JWST Cycle 1 UNCOVER Treasury survey. Detailed stellar population modeling using JWST NIRCam and NIRSpec data corroborates the primeval characteristics of these galaxies: low mass (~108 M ⊙), young, rapidly assembling, metal-poor, and star-forming. Interestingly, both galaxies are spatially resolved, having lensing-corrected rest-UV effective radii on the order of 300-400 pc, which are notably larger than other spectroscopically confirmed systems at similar redshifts. The observed dynamic range of z ≳ 10 sizes spans over 1 order of magnitude, implying a significant scatter in the size-mass relation at early times. Deep into the epoch of reionization, these discoveries elucidate the emergence of the first galaxies.

Keywords: Early universe, Galaxy formation, James Webb Space Telescope, Spectral energy distribution, Galaxy spectroscopy, High-redshift galaxies
MOSEL Survey: JWST Reveals Major Mergers/strong Interactions Drive the Extreme Emission Lines in the Early Universe. Extreme emission line galaxies (EELGs), where nebular emissions contribute 30%-40% of the flux in certain photometric bands, are ubiquitous in the early Universe (z &gt; 6). We utilize deep NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) to investigate the properties of companion galaxies (projected distance &lt;40 kpc, ∣dv∣ &lt; 10,000 km s-1) around EELGs at z ~ 3. Tests with TNG100 simulation reveal that nearly all galaxies at z = 3 will merge with at least one companion galaxy selected using similar parameters by z = 0. The median mass ratio of the most massive companion and the total mass ratio of all companions around EELGs is more than 10 times higher the control sample. Even after comparing with a stellar mass and stellar mass plus specific star formation rate (SFR)-matched control sample, EELGs have 3 to 5 times higher mass ratios than the brightest companion and total mass ratio of all companions. Our measurements suggest that EELGs are more likely to be experiencing strong interactions or undergoing major mergers irrespective of their stellar mass or specific SFRs. We suspect that gas cooling induced by strong interactions and/or major mergers could be triggering the extreme emission lines, and the increased merger rate might be responsible for the overabundance of EELGs at z &gt; 6.

Keywords: Interacting galaxies, Emission line galaxies, Galaxy mergers, Galaxy evolution, High-redshift galaxies
JWST Measurements of <SUP>13</SUP>C, <SUP>18</SUP>O, and <SUP>17</SUP>O in the Atmosphere of Super-Jupiter VHS 1256 b. Isotope ratios have recently been measured in the atmospheres of directly imaged and transiting exoplanets from ground-based observations. The arrival of JWST allows us to characterize exoplanetary atmospheres in further detail and opens up wavelengths inaccessible from the ground. In this work we constrain the carbon and oxygen isotopes 13C, 18O, and 17O from CO in the atmosphere of the directly imaged companion VHS 1256 b through retrievals of the ~4.1-5.3 μm NIRSpec G395H/F290LP observations from the early-release science program (ERS 1386). We detect and constrain 13C16O, 12C18O, and 12C17O at 32σ, 16σ, and 10σ confidence respectively, thanks to the very high signal-to-noise observations. We find the ratio of abundances are more precisely constrained than their absolute values, with ${}^{12}{\rm{C}}{/}^{13}{\rm{C}}={62}_{-2}^{+2}$ , in between previous measurements for companions (~30) and isolated brown dwarfs (~100). The oxygen isotope ratios are ${}^{16}{\rm{O}}{/}^{18}{\rm{O}}={425}_{-28}^{+33}$ and ${}^{16}{\rm{O}}{/}^{17}{\rm{O}}={1010}_{-100}^{+120}$ . All of the ratios are lower than the local interstellar medium and solar system, suggesting that abundances of the more minor isotopes are enhanced compared to the primary. This could be driven by isotope fractionation in protoplanetary disks, which can potentially alter the carbon and oxygen ratios through isotope selective photodissociation, gas/ice partitioning, and isotopic exchange reactions. In addition to CO, we constrain 1H ${}_{2}^{16}{\rm{O}}$ and 12C16O2 (the primary isotopologues of both species), but find only upper limits on 12C1H4 and 14N1H3. This work highlights the power of JWST to constrain isotopes in exoplanet atmospheres, with great promise in determining formation histories in the future.

Keywords: Exoplanet atmospheric composition , Isotopic abundances, Direct imaging, Extrasolar gaseous giant planets
Evolutionary Relationship between Sunspot Groups and Soft X-Ray Flares over Solar Cycles 21-25. Studying the interaction between solar flares and sunspot groups (SGs) is crucial for understanding and predicting solar activity. We examined the distribution, correlation, and flaring rates in the northern and southern hemispheres to reveal the relationship between different classes of soft X-ray (SXR) flares and different magnetic classifications of SGs. We discovered a significant north-south asymmetry in SXR flares and SG distribution over Solar Cycles (SC) 21-25. In the rising phase of SC24, the northern hemisphere's activity is significantly excessive. In the declining phase of SC24, the southern hemisphere's activity becomes significantly excessive. The total numbers of various SXR flares and SGs vary between the northern and southern hemispheres over the solar cycle. B-class flares are negatively correlated with all SGs at maximum but positively correlated at minimum. C-class flares correlate best with α and β SGs. M-class flares correlate best with β γ δ and β SGs. X-class flares correlate highest with β γ δ SGs. The flaring rate of each flare class is lowest for α SGs and highest for β γ δ SGs. The flaring rates are higher in the southern hemisphere than in the northern hemisphere. Our results demonstrate that solar flares originate from different sources of solar active regions; the high-energy flares tend to be caused by more complex magnetic fields.

Keywords: Solar activity, Solar flares, Sunspot groups
Rankine-Hugoniot Relations and Magnetic Field Enhancement in Turbulent Shocks. In fast collisionless shocks, the density and magnetic field increase and the plasma is heated. The compression and heating are ultimately determined by the Rankine-Hugoniot relations connecting the upstream and downstream parameters. The standard Rankine-Hugoniot relations take into account only mean upstream and downstream parameters. Observations at the Earth's bow shock show that the downstream magnetic field does not always relax to a uniform state, but large amplitude magnetic oscillations persist. Here, these Rankine-Hugoniot relations are extended to such turbulent shocks where the mean downstream magnetic field is accompanied by magnetic fluctuations. It is shown that the turbulent magnetic field pressure may substantially exceed the pressure of the mean field, while the density compression and heating may be only weakly affected. Thus, strong amplification of the rms magnetic field can be achieved at the expense of a modest reduction of plasma heating.

Keywords: Space plasmas, Interplanetary shocks, Planetary bow shocks, Plasma astrophysics, Shocks
The Maximum Energy of Shock-accelerated Cosmic Rays. Identifying the accelerators of Galactic cosmic ray (CR) protons with energies up to a few PeV (1015 eV) remains a theoretical and observational challenge. Supernova remnants (SNRs) represent strong candidates because they provide sufficient energetics to reproduce the CR flux observed at Earth. However, it remains unclear whether they can accelerate particles to PeV energies, particularly after the very early stages of their evolution. This uncertainty has prompted searches for other source classes and necessitates comprehensive theoretical modeling of the maximum proton energy, ${E}_{\max }$ , accelerated by an arbitrary shock. While analytic estimates of ${E}_{\max }$ have been put forward in the literature, they do not fully account for the complex interplay between particle acceleration, magnetic field amplification, and shock evolution. This paper uses a multizone, semianalytic model of particle acceleration based on kinetic simulations to place constraints on ${E}_{\max }$ for a wide range of astrophysical shocks. In particular, we develop relationships between ${E}_{\max }$ , shock velocity, size, and ambient medium. We find that SNRs can only accelerate PeV particles under a select set of circumstances, namely, if the shock velocity exceeds ~104 km s-1 and escaping particles drive magnetic field amplification. However, older and slower SNRs may still produce observational signatures of PeV particles due to populations accelerated when the shock was younger. Our results serve as a reference for modelers seeking to quickly produce a self-consistent estimate of the maximum energy accelerated by an arbitrary astrophysical shock. 1 1 Presented as a thesis to the Department of Astronomy and Astrophysics, The University of Chicago, in partial fulfillment of the requirements for a Ph.D. degree.

Keywords: Neutrino astronomy, Galactic cosmic rays, Supernova remnants, Shocks, Gamma-ray astronomy, Gamma-rays, Cosmic rays
SIMPLE: Simple Intensity Map Producer for Line Emission. We present the Simple Intensity Map Producer for Line Emission (SIMPLE), a public code for quickly simulating mock line-intensity maps, and an analytical framework for modeling intensity maps including observational effects. SIMPLE can be applied to any spectral line sourced by galaxies. The SIMPLE code is based on lognormal mock catalogs of galaxies including positions and velocities and assigns luminosities following the luminosity function. After applying a selection function to distinguish between detected and undetected galaxies, the code generates an intensity map, which can be modified with anisotropic smoothing, noise, a mask, and sky subtraction, and it calculates the power spectrum multipoles. We show that the intensity auto-power spectrum and the galaxy-intensity cross-power spectrum agree well with the analytical estimates in real space. We derive and show that the sky subtraction suppresses the intensity autopower spectrum and the cross-power spectrum on scales larger than the size of an individual observation. As an example application, we make forecasts for the sensitivity of an intensity mapping experiment similar to the Hobby─Eberly Telescope Dark Energy Experiment (HETDEX) to the cross-power spectrum of Lyα-emitting galaxies and the Lyα intensity. We predict that HETDEX will measure the galaxy-intensity cross-power spectrum with a high signal-to-noise ratio on scales of 0.04 h Mpc−1 &lt; k &lt; 1 h Mpc−1.

Keywords: Lyman-alpha galaxies, Observational cosmology, Large-scale structure of the universe
A Dragon Out of Breath? Monitoring High-velocity Outflows from the High-mass Gamma-Ray Binary LS 2883/PSR B1259-63 During the 2017-2021 Binary Cycle. Observations of the high-mass gamma-ray binary LS 2883/PSR B1259-63 with the Chandra X-ray Observatory during the 2011-2014 and 2014-2017 binary cycles have shown X-ray-emitting clumps, presumably ejected from the binary during periastron passages. These clumps traveled at projected velocities of ~0.1c and have shown evidence of being accelerated. The clumps also evolved in shape, size, and flux. We monitored this binary with Chandra during the 2017-2021 binary cycle to search for additional X-ray-emitting ejections. While we find evidence of extended emission in two of the six observations, it is unlike the clumps observed in the previous three binary cycles. More specifically, the extended emission is not well localized, and no bright clump is observed moving away from the binary. It is still unclear what caused the lack of X-ray-emitting clump in this orbital cycle, but it may be due to changes in the decretion disk of the Be star.

Keywords: Neutron stars, Be stars, High mass x-ray binary stars, Radio pulsars
Reconstruction of a Scale-dependent Gravitational Phase Transition. In this work we extend our earlier phenomenological model for a gravitational phase transition and its generalization to early times by letting the modifications in the linearly perturbed Einstein equations be scale dependent. These modifications are characterized as deviations of the parameters μ(z, k) and γ(z, k) from their values in general relativity (GR). The scale-dependent amplitudes of modified μ(z, k) and γ(z, k) and the parameters defining the phase transition, along with the standard cosmological parameters, are measured by various data combinations. Out of the perturbation parameters, we construct gravity eigenmodes that represent patterns of perturbations best detectable by data. We detect no significant deviation from GR in these parameters. However, the larger parameter space produced due to the new degrees of freedom allows for the reconciliation of various data sets that are in tension in ΛCDM. In particular, we find H 0 = 71.9 ± 9.2 from anisotropies of the cosmic microwave background as measured by Planck (and various measurements of the baryonic acoustic oscillations, in agreement with local Hubble measurements). We also find that the σ 8 tension between the measurements of the Dark Energy Survey and Planck is reduced to less than 1σ.

Keywords: Cosmology, Principal component analysis, General relativity, Cosmological constant
Understanding the Kinetic Energy Deposition within Molecular Clouds. According to the structures traced by 13CO spectral lines within 12CO molecular clouds (MCs), we investigate the contributions of their internal gas motions and relative motions to the total velocity dispersions of 12CO MCs. Our samples of 2851 12CO MCs harbor a total of 9556 individual 13CO structures, among which 1848 MCs (~65%) have one individual 13CO structure and the other 1003 MCs (~35%) have multiple 13CO structures. We find that the contribution of the relative motion between 13CO structures ( ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{re}}$ ) is larger than that from their internal gas motion ( ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{in}}$ ) in ~62% of 1003 MCs in the "Multiple" regime. In addition, we find that ${\sigma }_{{}^{13}\mathrm{CO},\mathrm{re}}$ tends to increase with the total velocity dispersion ( ${\sigma }_{{}^{12}\mathrm{CO},\mathrm{tot}}$ ) in our samples, especially for MCs with multiple 13CO structures. This result provides a manifestation of macroturbulence within MCs, which gradually becomes the dominant way of storing kinetic energy along with the development of MC scales.

Keywords: Molecular clouds, Interstellar medium
oMEGACat. I. MUSE Spectroscopy of 300,000 Stars within the Half-light Radius of ω Centauri. Omega Centauri (ω Cen) is the most massive globular cluster of the Milky Way and has been the focus of many studies that reveal the complexity of its stellar populations and kinematics. However, most previous studies have used photometric and spectroscopic data sets with limited spatial or magnitude coverage, while we aim to investigate it having full spatial coverage out to its half-light radius and stars ranging from the main sequence to the tip of the red giant branch. This is the first paper in a new survey of ω Cen that combines uniform imaging and spectroscopic data out to its half-light radius to study its stellar populations, kinematics, and formation history. In this paper, we present an unprecedented MUSE spectroscopic data set combining 87 new MUSE pointings with previous observations collected from guaranteed time observations. We extract spectra of more than 300,000 stars reaching more than 2 magnitudes below the main-sequence turnoff. We use these spectra to derive metallicity and line-of-sight velocity measurements and determine robust uncertainties on these quantities using repeat measurements. Applying quality cuts we achieve signal-to-noise ratios (S/Ns) of 16.47/73.51 and mean metallicity errors of 0.174/0.031 dex for the main-sequence stars (18 mag &lt;mag F625W  &lt; 22 mag) and red giant branch stars (16 mag &lt;mag F625W  &lt; 10 mag), respectively. We correct the metallicities for atomic diffusion and identify foreground stars. This massive spectroscopic data set will enable future studies that will transform our understanding of ω Cen, allowing us to investigate the stellar populations, ages, and kinematics in great detail.

Keywords: Globular star clusters, Star clusters, Galaxy nuclei