Sazuna/UAT_keywords huggingface dataset:
Fuzzy Dark Matter and Dark Matter Halo Cores. Whereas cold dark matter (CDM) simulations predict central dark matter cusps with densities that diverge as ρ(r) ∼ 1/r, observations often indicate constant-density cores with finite central densities ρ0 and a flat density distribution within a core radius r0. This paper investigates whether this core-cusp problem can be solved by fuzzy dark matter (FDM), a hypothetical particle with a mass of the order of m ≈ 10-22 eV and a corresponding de Broglie wavelength on astrophysical scales. We show that galaxies with CDM halo virial masses Mvir ≤ 1011M⊙ follow two core-scaling relations. In addition to the well-known universal core column density Σ0 ≡ ρ0 × r0 = 75 ${M}_{\odot }$ pc-2, core radii increase with virial masses as r0 ∼ ${M}_{\mathrm{vir}}^{\gamma }$ with γ of order unity. Using the simulations by Schive et al. we demonstrate that FDM can explain the r0-Mvir scaling relation if the virial masses of the observed galaxy sample scale with the formation redshift z as Mvir ∼ (1 + z)-0.4. The observed constant Σ0 is however in complete disagreement with FDM cores which are characterized by a steep dependence Σ0 ∼ r ${}_{0}^{-3}$ , independent of z. More high-resolution simulations are now required to confirm the simulations of Schive et al. and explore the transition region between the soliton core and the surrounding halo. If these results hold, FDM can be ruled out as the origin of observed dark matter cores and other physical processes are required to account for their formation.

Keywords: Cosmology, Dark matter distribution, Cold dark matter, Galaxies
Mg II and Fe II Fluxes of Luminous Quasars at z ∼ 2.7 and the Evaluation of the Baldwin Effect in the Flux-to-abundance Conversion Method for Quasars. To investigate the chemical abundance of broad-line region clouds in quasars at high redshifts, we performed near-infrared spectroscopy of six luminous quasars at z ∼ 2.7 with the WINERED spectrograph mounted on the New Technology Telescope at the La Silla Observatory, Chile. The measured Fe II/Mg II flux ratios nearly matched with the published data for 0.7 ≲ z ≲ 1.6, suggesting that there is no evolution over a long period of cosmic time, which is consistent with previous studies. To derive the chemical abundances from the measured equivalent widths (EWs), their dependence on nonabundance factors must be corrected. In our previous paper, we proposed a method to derive the [Mg/Fe] abundance ratio and the [Fe/H] abundance by correcting the dependence of EW(Mg II) and EW(Fe II) on the Eddington ratio. To the best of our knowledge, that was the first report to discuss the star formation history through a direct comparison with chemical evolution models. In the present study, we further investigated the dependence of EWs on luminosity, which is known as the Baldwin effect (BEff). Additional correction for the BEff significantly affects the derived chemical abundances for the six luminous quasars at z ∼ 2.7, and the resultant abundances agree well with the prediction of chemical evolution models. Given that most distant quasars found thus far are biased toward luminous ones, the correction of the measured EWs for the BEff is crucial for extending the chemical evolution study to higher redshifts.

Keywords: Chemical abundances, Quasars
Nucleosynthesis of an 11.8 M<SUB>⊙</SUB> Supernova with 3D Simulation of the Inner Ejecta: Overall Yields and Implications for Short-lived Radionuclides in the Early Solar System. Based on a 3D supernova simulation of an 11.8 M⊙ progenitor model with an initial solar composition, we study the nucleosynthesis using tracers covering the innermost 0.1 M⊙ of the ejecta. These ejecta are mostly proton-rich and contribute significant amounts of 45Sc and 64Zn. The production of heavier isotopes is sensitive to the electron fraction and hence the neutrino emission from the proto-neutron star. The yields of these isotopes are rather uncertain due to the approximate neutrino transport used in the simulation. In order to obtain the total yields for the whole supernova, we combine the results from the tracers with those for the outer layers from a suitable 1D model. Using the yields of short-lived radionuclides (SLRs), we explore the possibility that an 11.8 M⊙ supernova might have triggered the formation of the solar system and provided some of the SLRs measured in meteorites. In particular, we discuss two new scenarios that can account for at least the data on 41Ca, 53Mn, and 60Fe without exceeding those on the other SLRs.

Keywords: Isotopic abundances, Supernova neutrinos, Explosive nucleosynthesis, Core-collapse supernovae, Nucleosynthesis, Abundance ratios, Nuclear abundances, Chemical abundances, Supernova dynamics
The CGM at Cosmic Noon with KCWI: Outflows from a Star-forming Galaxy at z = 2.071. We present the first results from our "CGM at Cosmic Noon with KCWI" program to study gas flows in the circumgalactic medium (CGM) at z = 2-3. Combining the power of a high-resolution VLT/UVES quasar spectrum, a Hubble Space Telescope/Advanced Camera for Surveys image, and integral field spectroscopy with Keck/KCWI (Keck Cosmic Web Imager), we detected Lyα emission from a 1.7L* galaxy at zgal = 2.0711 associated with a Lyman limit system with weak Mg II (Wr(2796) = 0.24 Å) in quasar field J143040+014939. The galaxy is star-forming (SFRFUV = 37.8 M☉ yr-1) and clumpy: either an edge-on disk (i = 85°) or, less likely, a major merger. The background quasar probes the galaxy at an impact parameter of D = 66 kpc along the projected galaxy minor axis (Φ = 89°). From photoionization modeling of the absorption system, we infer a total line-of-sight CGM metallicity of $[\mathrm{Si}/{\rm{H}}]=-{1.5}_{-0.3}^{+0.4}$ . The absorption system is roughly kinematically symmetric about zgal, with a full Mg II velocity spread of ∼210 km s-1. Given the galaxy-quasar orientation, CGM metallicity, and gas kinematics, we interpret this gas as an outflow that has likely swept up additional material. By modeling the absorption as a polar outflow cone, we find the gas is decelerating with average radial velocity Vout = 109-588 km s-1 for half-opening angles of θ0 = 14°-75°. Assuming a constant Vout, it would take on average tout ∼ 111-597 Myr for the gas to reach 66 kpc. The outflow is energetic, with a mass outflow rate of ${\dot{M}}_{\mathrm{out}}\lt 52\pm 37$ M☉ yr-1 and mass loading factor of η &lt; 1.4 ± 1.0. We aim to build a sample of ∼50 Mg II absorber-galaxy pairs at this epoch to better understand gas flows when they are most actively building galaxies.

Keywords: Quasar absorption line spectroscopy, Galaxy evolution, Circumgalactic medium, Lyman-alpha galaxies, High-redshift galaxies
Long- and Short-term Variability of Galactic Cosmic-Ray Radial Intensity Gradients between 1 and 9.5 au: Observations by Cassini, BESS, BESS-Polar, PAMELA, and AMS-02. Spatial gradients of galactic cosmic-ray (GCR) fluxes are important for studying charged particle transport in the heliosphere. Little is known so far about how these gradients evolve with time. Here we present how the radial gradient (Gr) evolves between 2006 January and 2017 September using Cassini measurements of &gt;300 MeV protons, which we combine with proton spectra obtained by advanced observatories at Earth (BESS, BESS-Polar, PAMELA, and AMS-02). All gradient calculations were performed for a nearly constant heliocentric distance of Cassini from Earth's orbit and near the ecliptic, thus revealing only how Gr changes with time. The variability patterns of Gr are well established as they rely on a single data set for ∼9.5 au and accurately cross-calibrated GCR spectra for Earth at 1 au. We show that over solar-cycle timescales, Gr is regulated by both the polarity of the solar magnetic field and the solar-cycle phase. During the negative-polarity phase (A &lt; 0, 2006-2014), gradients are stronger and more stable with an average of Gr = 3.5 ± 0.3%/au and with evidence of a minimum around the 2009 solar minimum. The gradient peaks at ∼4%/au around the solar maximum and subsequently experiences a gradual drop to ∼2%/au in the A &gt; 0 phase (2014-2017). Regular Gr enhancements over yearly or biennial timescales are also observed, in phase with quasi-biennial oscillations in GCR intensity. While all aforementioned results are based on Cassini measurements that are integral in energy, they are most representative for GCR protons in the low gigaelectronvolt range.

Keywords: Galactic cosmic rays, Solar system gas giant planets, Heliosphere, Solar cycle
GRB 160625B: Evidence for a Gaussian-shaped Jet. We present multiwavelength modeling of the afterglow from the long γ-ray burst (GRB) 160625B using Markov Chain Monte Carlo techniques of the afterglowpy Python package. GRB 160625B is an extremely bright burst with a rich set of observations spanning from radio to γ-ray frequencies. These observations range from ∼0.1 days to &gt;1000 days, thus making this event extremely well suited to such modeling. In this work we compare top-hat and Gaussian jet structure types in order to find best-fit values for the GRB jet collimation angle, viewing angle, and other physical parameters. We find that a Gaussian-shaped jet is preferred (2.7σ-5.3σ) over the traditional top-hat model. Our estimate for the opening angle of the burst ranges from 1°26 to 3°90, depending on jet-shape model. We also discuss the implications that assumptions on jet shape, viewing angle, and particularly the participation a fraction of electrons have on the final estimation of GRB intrinsic energy release and the resulting energy budget of the relativistic outflow. Most notably, allowing the participation fraction to vary results in an estimated total relativistic energy of ∼1053 erg. This is two orders of magnitude higher than when the total fraction is assumed to be unity; thus, this parameter has strong relevance for placing constraints on long GRB central engines, details of the circumburst media, and host environment.

Keywords: Gamma-ray bursts, Relativistic jets
Polytropic Index of the Solar Wind Ions Near the Earth Calculated Using a Homogeneous Magnetohydrodynamic Bernoulli Integral. This paper, using the data of Cluster during 2001-2010, studies the polytropic processes of solar wind ions near the Earth. We calculate the polytropic index of ions for different outward electromagnetic energy ratios δE×B and entropy parameter changes δentropy based on the approach of the homogeneous magnetohydrodynamic Bernoulli integral (MBI). Solar wind ions have a broad distribution of polytropic indices with multiple peaks in the range of [-7.0, 6.0]. The median polytropic indices are 1.264, 1.321, and 1.418 at δentropy = 5% for δE×B ≤ 5%, 3%, and 1% and 1.241 and 1.097 at δE×B ≤ 5% for δentropy ≤ 3% and 1%. In most of the dayside, the median polytropic index of the solar wind basically increases with increasing geocentric distance and has an obvious dawn-dusk asymmetry because of the solar wind-magnetosphere interaction. The polytropic indices near the bow shock are basically within the range from ∼-1.0 to ∼3.0, and their median values are between 0.5 and 1.3. Those polytropic indices of solar wind ions far away from the bow shock are basically in the range from ∼-2.0 to ∼6.0 and have median values between 1.6 and 2.2. Near the terminator, the median polytropic index has no obvious radial distribution, but it has an obvious dawn-dusk asymmetry. The above results suggest that polytropic indices in the solar wind become smaller after being scattered or rebounded by a fast shock wave. It is also found that the polytropic processes in the solar wind near the Earth are closely related to those in the magnetosheath.

Keywords: Solar physics, Solar wind, Plasma physics
Gravity and Rotation Drag the Magnetic Field in High-mass Star Formation. The formation of hot stars out of the cold interstellar medium lies at the heart of astrophysical research. Understanding the importance of magnetic fields during star formation remains a major challenge. With the advent of the Atacama Large Millimeter Array, the potential to study magnetic fields by polarization observations has tremendously progressed. However, the major question remains how much magnetic fields shape the star formation process or whether gravity is largely dominating. Here, we show that for the high-mass star-forming region G327.3 the magnetic field morphology appears to be dominantly shaped by the gravitational contraction of the central massive gas core where the star formation proceeds. We find that in the outer parts of the region, the magnetic field is directed toward the gravitational center of the region. Filamentary structures feeding the central core exhibit U-shaped magnetic field morphologies directed toward the gravitational center as well, again showing the gravitational drag toward the center. The inner part then shows rotational signatures, potentially associated with an embedded disk, and there the magnetic field morphology appears to be rotationally dominated. Hence, our results demonstrate that for this region gravity and rotation are dominating the dynamics and shaping the magnetic field morphology.

Keywords: Interstellar dynamics, Interstellar magnetic fields, Collapsing clouds, Star formation, Interstellar medium, Dynamical evolution
Standard Candles and Sirens Rescue H<SUB>0</SUB>. We show that future observations of binary neutron star systems with electromagnetic counterparts together with the traditional probes of low- and high-redshift Type Ia supernovae (SNe Ia) can help resolve the Hubble tension. The luminosity distance inferred from these probes and its scatter depend on the underlying cosmology. By using the gravitational lensing of light or gravitational waves emitted by, and peculiar motion of, these systems we derive constraints on the sum of neutrino masses, the equation of state of dark energy parameterized in the form ${w}_{0}+{w}_{a}(1-a)$ , along with the Hubble constant and cold dark matter density in the universe. We show that even after marginalizing over poorly constrained physical quantities, such as the sum of neutrino masses and the nature of dark energy, low-redshift gravitational-wave observations, in combination with SNe Ia, have the potential to rule out new physics as the underlying cause of the Hubble tension at ≳5.5σ.

Keywords: Cosmological parameters, Neutrino masses, Type Ia supernovae, Gravitational waves, Dark energy
Barred Galaxies in the IllustrisTNG Simulation. Almost two-thirds of disk galaxies in the local universe host bars, which serve as important drivers of secular evolutionary processes. While cosmological simulations are powerful tools to study the formation and evolution of galaxies, they have often struggled to generate reasonable bar populations. We measure the fraction, size, and strength of bars in 3866 disk galaxies from the TNG100 run of the advanced cosmological simulation IllustrisTNG. Consistent with observations, about 55% of disk galaxies with stellar mass ${M}_{* }\approx {10}^{10.6}\,{M}_{\odot }$ are barred, and the relation between bar size and total stellar mass is similar to that found in near-infrared surveys. However, the formation of bars is suppressed in galaxies with ${M}_{* }\lt {10}^{10.6}\,{M}_{\odot }$ , which may result from the difficulty TNG100 has in resolving short bars with radius $\lt 1.4\,\mathrm{kpc}$ . In contrast, up to 75% of massive disk galaxies with ${M}_{* }\gt {10}^{10.6}\,{M}_{\odot }$ have bars, ∼10%-20% higher than observed. TNG100 overproduces relatively short bars (radius ∼1.4-3 kpc) with respect to the mass-bar size relation observed in near-infrared surveys. Tracing the progenitors of z = 0 massive galaxies we find that the bar fraction increases from 25% to 63% between z = 1 and 0. Instead if we select all disk galaxies during z = 0-1 with a constant mass cut of ${M}_{* }\geqslant {10}^{10.6}\,{M}_{\odot }$ we find that the bar fraction is a nearly constant 60%.

Keywords: Barred spiral galaxies, Astronomical simulations
The Secular Evolution of a Uniform Density Star Cluster Immersed in a Compressible Galactic Tidal Field. Nuclear stellar clusters are common in the center of galaxies. We consider the possibility that their progenitors assumed to be globular clusters may have formed elsewhere, migrated to, and assembled near their present location. The main challenge for this scenario is whether globular clusters can withstand the tidal field of their host galaxies. Our analysis suggests that provided the mass-density distribution of background potential is relatively shallow, as in some galaxies with relatively flat surface brightness profiles, the tidal field near the center of galaxies may be shown to be able to compress rather than disrupt a globular cluster at a distance from the center much smaller than the conventionally defined "tidal disruption radius" rt. To do so, we adopt a previously constructed formalism and consider the secular evolution of star clusters with a homogeneous mass-density distribution. We analytically solve the secular equations in the limit that the mass density of stars in the galactic center approaches a uniform distribution. Our model indicates that a star cluster could travel to distances much smaller than rt without disruption, thus potentially contributing to the formation of the nuclear cluster. However, appropriate numerical N-body simulations are needed to confirm our analytic findings.

Keywords: Globular star clusters, Moving clusters, Stellar astronomy, Star clusters
Herschel Gould Belt Survey Observations of Dense Cores in the Cepheus Flare Clouds. We present Herschel SPIRE and PACS maps of the Cepheus Flare clouds L1157, L1172, L1228, L1241, and L1251, observed by the Herschel Gould Belt Survey of nearby star-forming molecular clouds. Through modified blackbody fits to the SPIRE and PACS data, we determine typical cloud column densities of (0.5-1.0) × 1021 cm-2 and typical cloud temperatures of 14-15 K. Using the getsources identification algorithm, we extract 832 dense cores from the SPIRE and PACS data at 160-500 μm. From placement in a mass versus size diagram, we consider 303 to be candidate prestellar cores, and 178 of these to be "robust" prestellar cores. From an independent extraction of sources at 70 μm, we consider 25 of the 832 dense cores to be protostellar. The distribution of background column densities coincident with candidate prestellar cores peaks at (2-4) × 1021 cm-2. About half of the candidate prestellar cores in Cepheus may have formed as a result of the widespread fragmentation expected to occur within filaments of "transcritical" line mass. The lognormal robust prestellar core mass function (CMF) drawn from all five Cepheus clouds peaks at 0.56 M⊙ and has a width of ∼0.5 dex, similar to that of Aquila's CMF. Indeed, the width of Cepheus's aggregate CMF is similar to the stellar system initial mass function (IMF). The similarity of CMF widths in different clouds and the system IMF suggests a common, possibly turbulent origin for seeding the fluctuations that evolve into prestellar cores and stars.

Keywords: Initial mass function, Interstellar filaments, Molecular clouds, Dense interstellar clouds, Young stellar objects, Star formation, Interstellar medium, Protostars
Stochastic and Quasi-adiabatic Electron Heating in Quasi-parallel Shocks. Using Magnetospheric Multiscale observations at the Earth's quasi-parallel bow shock we demonstrate that electrons are heated by two different mechanisms: a quasi-adiabatic heating process during magnetic field compression, characterized by the isotropic temperature relation $T/B={({T}_{0}/{B}_{0})({B}_{0}/B)}^{\alpha }$ with α = 2/3 when the electron heating function $| {\chi }_{e}| \lt 1$ , and a stochastic heating process when $| {\chi }_{e}| \gt 1$ . Both processes are controlled by the value of the stochastic heating function ${\chi }_{j}={m}_{j}{q}_{j}^{-1}{B}^{-2}\mathrm{div}({{\boldsymbol{E}}}_{\perp })$ for particles with mass mj and charge qj in the electric and magnetic fields ${\boldsymbol{E}}$ and ${\boldsymbol{B}}$ . Test-particle simulations are used to show that the stochastic electron heating and acceleration in the studied shock are accomplished by waves at frequencies (0.4-5) fce (electron gyrofrequency) for bulk heating, and waves $f\gt 5\,{f}_{{ce}}$ for acceleration of the tail of the distribution function. Stochastic heating can give rise to flat-top electron distribution functions, frequently observed near shocks. It is also shown that obliquely polarized electric fields of electron cyclotron drift and ion acoustic instabilities scatter the electrons into the parallel direction and keep the isotropy of the electron distribution. The results reported in this paper may be relevant to electron heating and acceleration at interplanetary shocks and other astrophysical shocks.

Keywords: Shocks, Planetary bow shocks, Plasma astrophysics
The Rapid Variability of Wave Electric Fields Within and Near Quasiperpendicular Interplanetary Shock Ramps: STEREO Observations. We present STEREO observations within 1500 proton gyroradii of 12 quasiperpendicular interplanetary shocks, with long-duration burst mode electric field acquisition by S/WAVES enabling observation of the evolution of waves throughout the entire ramp of interplanetary shocks. The shocks are low Mach number (Mf ∼ 1-5), with beta (β) ∼0.2-1.8. High variability in frequency, amplitude, and wave mode is observed upstream, downstream, and in shock ramps. Observations in every region include ion acoustic-like waves, electron cyclotron drift instability (ECDI) driven waves, electrostatic solitary waves, and high frequency whistler mode waves. We also show for the first time the existence of electrostatic waves with frequencies in the ion acoustic range, which are frequency dispersed in time and the first observations of ECDI-driven waves at interplanetary shocks. The waves are bursty, large amplitude (∼5-&gt;200 mV m-1), and seen in all three regions. All wave modes are more commonly observed downstream than upstream.

Keywords: Solar wind, Interplanetary shocks, Space plasmas
Analysis of XMM-Newton Observations of Supernova Remnant W49B and Clues to the Progenitor. W49B is a supernova remnant (SNR) discovered over 60 yr ago in early radio surveys. It has since been observed over the entire wavelength range, with the X-ray morphology resembling a centrally filled SNR. The nature of its progenitor star is still debated. Applying Smoothed Particle Inference techniques to analyze the X-Ray emission from W49B, we characterize the morphology and abundance distribution over the entire remnant. We also infer the density structure and derive the mass of individual elements present in the plasma. The morphology is consistent with an interaction between the remnant and a dense medium along the eastern edge, and some obstruction toward the west. We find a total mass of 130 $(\pm 16)$ M ${}_{\odot }$ and an estimated ejecta mass of 1.2 $(\pm 0.2)$ M ${}_{\odot }$ . Comparison of the inferred abundance values and individual element masses with a wide selection of SN models suggests that deflagration-to-detonation (DDT) Type Ia models are the most compatible, with Fe abundance being the major discriminating factor. The general agreement between our abundance measurements and those from previous studies suggests that disagreement between various authors is more likely due to the choice of models used for comparison, rather than the abundance values themselves. While our abundance results lean toward a Type Ia origin, ambiguities in the interpretation of various morphological and spectral characteristics of W49B do not allow us to provide a definitive classification.

Keywords: Nucleosynthesis, Supernova remnants, Circumstellar matter, X-ray sources, Interstellar medium, Supernovae