Sazuna/UAT_keywords huggingface dataset:
Measuring the Mass of Missing Baryons in the Halo of Andromeda Galaxy with Gamma-Ray Observations. It has been suggested that a huge amount of baryon resides in the circumgalactic medium (CGM) extending out to the virial radii of galaxies. In this work we attempt to measure the baryon mass in the CGM with a novel method based on the gamma-ray observations of the extended halo of the Andromeda galaxy Messier 31 (M31). Since cosmic-ray particles generated inside the galaxy will eventually escape to the CGM, they will produce gamma-ray emission via the proton-proton collision with the CGM and produce gamma-rays. Different from some traditional measurements that are sensitive only to certain metallic ions in specific temperature range, the hadronic gamma-ray flux is sensitive to baryonic gases in all phases and does not rely on the metallicity in the halo, hence the measured gamma-ray flux from the galaxy's halo can be used to constrain the mass of the CGM. By dealing with the cosmic-ray transport in the halo and calculating the hadronic gamma-ray intensity, we find that the total baryon mass contained within the virial radius is less than (1.4-5) × 1010 M⊙ according to the gamma-ray intensity obtained with a model-dependent analysis. It implies that the CGM of Andromeda galaxy may not account for more than 30% of the missing baryons, but the result is subject to uncertainties from the gamma-ray intensity upper limit, diffusion coefficient of the cosmic-rays in the halo, as well as the stellar mass and dark matter halo mass of the galaxy. This method will become more constraining provided better understandings on these issues and more sensitive gamma-ray telescopes in the future.

Keywords: Galaxy dark matter halos, Missing mass, Gamma-ray sources, Circumgalactic medium, Andromeda Galaxy, Cosmic rays
Estimating Lifetimes of UV-selected Massive Galaxies at 0.5 ≤ z ≤ 2.5 in the COSMOS/UltraVISTA Field through Clustering Analyses. To investigate the lifetimes of red sequence (RS), blue cloud (BC), and green valley (GV) galaxies, we derive their lifetimes using clustering analyses at 0.5 ≤ z ≤ 2.5 in the COSMOS/UltraVISTA field. Several essentials that may influence the lifetime estimation have been explored, including the dark matter (DM) halo mass function (HMF), the width of the redshift bin, the growth of DM halos within each redshift bin, and the stellar mass. We find that the HMF difference results in scatters of ∼0.2 dex on the lifetime estimation, adopting a redshift bin width of ∆z = 0.5 is good enough to estimate the lifetime, and no significant effect on lifetime estimation is found due to the growth of DM halos within each redshift bin. The galaxy subsamples with higher stellar masses generally have shorter lifetimes, but the lifetimes in different subsamples at z &gt; 1.5 tend to be independent of stellar mass. Consistently, the clustering-based lifetime for each galaxy subsample agrees well with that inferred using the spectral energy distribution modeling. Moreover, the lifetimes of the RS and BC galaxies also coincide well with their typical gas-depletion timescales attributed to the consumption of star formation. Interestingly, the distinct lifetime behaviors of the GV galaxies at z ≤ 1.5 and z &gt; 1.5 cannot be fully accounted for by their gas-depletion timescales. Instead, this discrepancy between the lifetimes and gas-depletion timescales of the GV galaxies suggests that there are additional physical processes, such as feedback of active galactic nuclei, which accelerates the quenching of GV galaxies at high redshifts.

Keywords: Galaxy formation, Galaxy evolution, Red sequence galaxies, Galaxy quenching, High-redshift galaxies
The Distribution and Evolution of Quasar Proximity Zone Sizes. In this paper, we study the sizes of quasar proximity zones with synthetic quasar absorption spectra obtained by postprocessing a Cosmic Reionization On Computers (CROC) simulation. CROC simulations have both relatively large box sizes and high spatial resolution, allowing us to resolve Lyman limit systems (LLSs), which are crucial for modeling the quasar absorption spectra. We find that before reionization, most quasar proximity zone sizes grow steadily for ∼10 Myr, while after reionization, they grow rapidly but only for ∼0.1 Myr. We also find a slow growth of Robs with decreasing turn-on redshift. In addition, we find that ∼1%-2% of old quasars (30 Myr old) display extremely small proximity zone sizes (&lt;1 proper Mpc), the vast majority of which are due to the occurrence of a damped Lyα absorber (DLA) or an LLS along the line of sight. These DLAs and LLSs are contaminated with metal, which offers a way to distinguish them from the normal proximity zones of young quasars.

Keywords: Intergalactic clouds, Quasar absorption line spectroscopy, Quasars, Galaxy environments, Lyman limit systems, Large-scale structure of the universe, Damped Lyman-alpha systems, Extragalactic astronomy, Radiative transfer simulations, Reionization, Astronomical simulations
Magnetic Field and Plasma Density Observations of a Pressure Front by Voyager 1 during 2020 in the Very Local Interstellar Medium. Voyager 1 has been moving through the very local interstellar medium (VLISM) from the time that it crossed the heliopause on 2012/DOY 238 to 2020/DOY 292. Three notable objects in the magnetic field of the VLISM have been observed: two shocks and one pressure front. This paper reports the observation of a fourth object observed near 2020/DOY 147. There were no upstream electron plasma oscillations of the type often observed ahead of shocks, abrupt increases in energetic particles, or fluctuations in the 48 s increments of the magnetic field associated with this feature, suggesting that it was probably not a shock. This feature was associated with a relatively large increase in the magnetic field strength (B2/B1 = 1.35) and in the electron density determined by the Plasma Wave Science experiment (N2/N1 = 1.36) using a new method described in this paper. This feature appears to be a pressure front associated with a compressive wave in the VLISM. The two shocks and the two pressure fronts were associated with the four largest maxima observed in B(t) between 2012/DOY 238 and 2020/DOY 292. Each feature was associated with a jump-ramp structure. The jump-ramp structures were separated by long relatively undisturbed quiet intervals.

Keywords: Interstellar magnetic fields
Reaching the Oldest Stars beyond the Local Group: Ancient Star Formation in UGC 4483. We present new WFC3/UVIS observations of UGC 4483, the closest example of a metal-poor blue compact dwarf galaxy, with a metallicity of Z ≃ 1/15 Z⊙ and located at a distance of D ≃ 3.4 Mpc. The extremely high quality of our new data allows us to clearly resolve the multiple stellar evolutionary phases populating the color-magnitude diagram (CMD), to reach more than 4 mag deeper than the tip of the red giant branch, and to detect for the first time core He-burning stars with masses ≲2 M⊙, populating the red clump and possibly the horizontal branch (HB) of the galaxy. By applying the synthetic CMD method to our observations, we determine an average star formation rate over the whole Hubble time of at least $(7.01\pm 0.44)\times {10}^{-4}$ ${M}_{\odot }\,{{yr}}^{-1}$ , corresponding to a total astrated stellar mass of $(9.60\pm 0.61)\times {10}^{6}$ M⊙, 87% of which went into stars at epochs earlier than 1 Gyr ago. With our star formation history recovery method we find the best fit with a distance modulus of DM = 27.45 ± 0.10, slightly lower than previous estimates. Finally, we find strong evidence of an old (≳10 Gyr) stellar population in UGC 4483 thanks to the detection of an HB phase and the identification of six candidate RR Lyrae variable stars. * Based on observations obtained with the NASA/ESA Hubble Space Telescope at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA Contract NAS 5-26555.

Keywords: Blue compact dwarf galaxies, Stellar populations, Galaxy stellar content, Star formation, Galaxy evolution
Effects of Density Fluctuations on Alfvén Wave Turbulence in a Coronal Hole. We present a study of density fluctuations in coronal holes. We used a reduced magnetohydrodynamic (RMHD) model that incorporated observationally constrained density fluctuations to determine whether density fluctuations in coronal holes can enhance Alfvén wave reflection and dissipation, thereby heating coronal holes and driving the fast solar wind. We show results for two models of the background atmosphere. Each model is a solution of the momentum equation and includes the effects of wave pressure on the solar wind outflow. In the first model, the plasma density and Alfvén speed vary smoothly with height. Wave reflection is relatively weak in the smooth model, resulting in a low energy dissipation rate. In the second model, we include additional density fluctuations along the flux tube based on the observations. We find that density ρ fluctuations on the order of δρ/ρ ∼ 0.24 increase the Alfvén wave turbulence to levels sufficient to heat the open field regions in coronal holes.

Keywords: Solar atmosphere, The Sun, Solar coronal heating, Solar physics, Solar corona, Solar coronal holes
The Black Hole Mass of the z = 2.805 Multiply Imaged Quasar SDSS J2222+2745 from Velocity-resolved Time Lags of the C IV Emission Line. We present the first results of a 4.5 yr monitoring campaign of the three bright images of multiply imaged z = 2.805 quasar SDSS J2222+2745 using the Gemini North Multi-Object Spectrograph and the Nordic Optical Telescope. We take advantage of gravitational time delays to construct light curves surpassing 6 yr in duration in the observed frame and achieve an average spectroscopic cadence of 10 days during the 8 months of visibility per season. Using multiple secondary calibrators and advanced reduction techniques, we achieve percent-level spectrophotometric precision and carry out an unprecedented reverberation mapping analysis, measuring both integrated and velocity-resolved time lags for the C IV emission line. The full line lags the continuum by ${\tau }_{\mathrm{cen}}={36.5}_{-3.9}^{+2.9}$ rest-frame days. We combine our measurement with published C IV emission line lags and derive the rBLR - L relationship ${\mathrm{log}}_{10}(\tau /{\rm{d}}{\rm{a}}{\rm{y}})=(0.99\,\pm 0.07)+(0.48\pm 0.03){\mathrm{log}}_{10}[\lambda {L}_{\lambda }(1350\,{\rm{A}}{\rm{A}})/{10}^{44}\,{{\rm{e}}{\rm{r}}{\rm{g}}{\rm{s}}}^{-1}]$ with 0.30 ± 0.06 dex intrinsic scatter. The velocity-resolved lags are consistent with circular Keplerian orbits, with ${\tau }_{\mathrm{cen}}={86.2}_{-5.0}^{+4.5}$ , ${25}_{-15}^{+11}$ , and ${7.5}_{-3.5}^{+4.2}$ rest-frame days for the core, blue wing, and red wing, respectively. Using σline with the mean spectrum and assuming ${\mathrm{log}}_{10}({f}_{\mathrm{mean},\sigma })=0.52\pm 0.26$ , we derive ${\mathrm{log}}_{10}({M}_{\mathrm{BH}}/{M}_{\odot })=8.63\pm 0.27$ . Given the quality of the data, this system represents a unique benchmark for calibration of MBH estimators at high redshift. Future work will present dynamical modeling of the data to constrain the virial factor f and MBH.

Keywords: Supermassive black holes, Strong gravitational lensing, Active galactic nuclei, Reverberation mapping
The Hubble Constant from Infrared Surface Brightness Fluctuation Distances. We present a measurement of the Hubble constant H0 from surface brightness fluctuation (SBF) distances for 63 bright, mainly early-type galaxies out to 100 Mpc observed with the WFC3/IR on the Hubble Space Telescope (HST). The sample is drawn from several independent HST imaging programs using the F110W bandpass, with the majority of the galaxies being selected from the MASSIVE survey. The distances reach the Hubble flow with a median statistical uncertainty per measurement of 4%. We construct the Hubble diagram with these IR SBF distances and constrain H0 using four different treatments of the galaxy velocities. For the SBF zero-point calibration, we use both the existing tie to Cepheid variables, updated for consistency with the latest determination of the distance to the Large Magellanic Cloud from detached eclipsing binaries, and a new tie to the tip of the red giant branch (TRGB) calibrated from the maser distance to NGC 4258. These two SBF calibrations are consistent with each other and with theoretical predictions from stellar population models. From a weighted average of the Cepheid and TRGB calibrations, we derive H0 = 73.3 ± 0.7 ± 2.4 km s-1 Mpc-1, where the error bars reflect the statistical and systematic uncertainties. This result accords well with recent measurements of H0 from Type Ia supernovae, time delays in multiply lensed quasars, and water masers. The systematic uncertainty could be reduced to below 2% by calibrating the SBF method with precision TRGB distances for a statistical sample of massive early-type galaxies out to the Virgo cluster measured with the James Webb Space Telescope. * Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. These observations come from GO Programs #11711, #11712, #12450, #14219, #14654, #14771, #14804, #15265, #15329.

Keywords: Galaxy distances, Cosmological parameters, Observational cosmology, Distance indicators, Early-type galaxies
A First Chandra View of the Cool Core Cluster A1668: Offset Cooling and AGN Feedback Cycle. We present a multiwavelength analysis of the cluster A1668, performed by means of new EVLA and Chandra observations and archival Hα data. The radio images exhibit a small central source (∼14 kpc at 1.4 GHz) with L1.4GHz ∼ 6 · 1023 W Hz-1. The mean spectral index between 1.4 GHz and 5 GHz is ∼-1, consistent with the usual indices found in BCGs. The cooling region extends for 40 kpc, with bolometric X-ray luminosity Lcool = 1.9 ± 0.1 · 1043 erg s-1. We detect an offset of ∼6 kpc between the cluster BCG and the X-ray peak, and another offset of ∼7.6 kpc between the Hα and the X-ray peaks. We discuss possible causes for these offsets, which suggest that the coolest gas is not condensing directly from the lowest-entropy gas. In particular, we argue that the cool ICM was drawn out from the core by sloshing, whereas the Hα filaments were pushed aside from the expanding radio galaxy lobes. We detect two putative X-ray cavities, spatially associated with the west radio lobe (cavity A) and the east radio lobe (cavity B). The cavity power and age of the system are Pcav ∼ 9 × 1042 erg s-1 and tage ∼ 5.2 Myr, respectively. Evaluating the position of A1668 in the cooling luminosity-cavity power parameter space, we find that the AGN energy injection is currently consistent within the scatter of the relationship, suggesting that offset cooling is likely not breaking the AGN feedback cycle.

Keywords: Galaxy clusters, Cooling flows, Radio lobes, Active galactic nuclei, Abell clusters, Intracluster medium, Radio sources
It's Cloud's Illusions I Recall: Mixing Drives the Acceleration of Clouds from Ram Pressure Stripped Galaxies. Ram pressure stripping can remove gas from satellite galaxies in clusters via a direct interaction between the intracluster medium (ICM) and the interstellar medium. This interaction is generally thought of as a contact force per area; however, we point out that these gases must interact in a hydrodynamic fashion and argue that this will lead to the mixing of the galactic gas with the ICM wind. We develop an analytic framework for how mixing is related to the acceleration of stripped gas from a satellite galaxy. We then test this model using three "wind-tunnel" simulations of Milky Way-like galaxies interacting with a moving ICM and find excellent agreement with predictions using the analytic framework. Focusing on the dense clumps in the stripped tails, we find that they are nearly uniformly mixed with the ICM, indicating that all gas in the tail mixes with the surroundings and dense clumps are not separate entities to be modeled differently than diffuse gas. We find that while mixing drives the acceleration of stripped gas, the density and velocity of the surrounding wind will determine whether the mixing results in the heating of stripped gas into the ICM or the cooling of the ICM into dense clouds.

Keywords: Galaxy clusters, Hydrodynamical simulations, Ram pressure stripped tails, Galaxy evolution, Intracluster medium
The Planck Submillimeter Properties of Galactic High-mass Star-forming Regions: Dust Temperatures, Luminosities, Masses, and Star Formation Efficiency. Massive star formation occurs in the interior of giant molecular clouds and proceeds through many stages. In this work, we focus on massive young stellar objects (MYSOs) and ultracompact H II regions (UCH II), where the former are enshrouded in dense envelopes of dust and gas, the latter of which has begun dispersing. By selecting a complete sample of MYSOs and UCH II from the Red MSX Source (RMS) survey database, we combine Planck and IRAS data and build their spectral energy distributions. With these, we estimate the physical properties (dust temperatures, mass, luminosity) of the sample. Because the RMS database provides unique solar distances, it also allows the instantaneous star formation efficiency (SFE) to be investigated as a function of Galactocentric radius. We find that the SFE increases between 2 and 4.5 kpc, where it reaches a peak, likely in correspondence with the accumulation of molecular material at the end of the Galactic bar. It then stays approximately constant up to 9 kpc, after which it linearly declines, in agreement with predictions from extragalactic studies. This behavior suggests the presence of a significant amount of undetected molecular gas at RG &gt; 8 kpc. Finally, we present diagnostic colors that can be used to identify sites of massive star formation.

Keywords: Young stellar objects, Protostars, Compact H II region, H II regions
Near-infrared Coronal Line Observations of Dwarf Galaxies Hosting AGN-driven Outflows. We have obtained Keck near-infrared spectroscopy of a sample of nine M⋆ &lt; 1010 M☉ dwarf galaxies to confirm active galactic nuclei (AGNs) activity and the presence of galaxy-wide, AGN-driven outflows through coronal line (CL) emission. We find strong CL detections in 5/9 galaxies (55%) with line ratios incompatible with shocks, confirming the presence of AGNs in these galaxies. Similar CL detection rates are found in larger samples of more massive galaxies hosting type 1 and 2 AGNs. We investigate the connection between the CLs and galaxy-wide outflows by analyzing the kinematics of the CL region as well as the scaling of gas velocity with ionization potential of different CLs. In addition, using complementary Keck Cosmic Web Imager observations of these objects, we find that the outflow velocities measured in [Si VI] are generally faster than those seen in [O III]. The galaxies with the fastest outflows seen in [O III] also have the highest [Si VI] luminosity. The lack of J-band CN absorption features, which are often associated with younger stellar populations, provides further evidence that these outflows are driven by AGNs in low-mass galaxies.

Keywords: AGN host galaxies, Dwarf galaxies, Active galaxies, Seyfert galaxies, Active galactic nuclei, Galaxy evolution, Near infrared astronomy
Nonequilibrium Equation of State in Stellar Atmospheres. In the stellar chromospheres, radiative energy transport is dominated by only the strongest spectral lines. For these lines, the approximation of local thermodynamic equilibrium (LTE) is known to be very inaccurate, and a state of equilibrium cannot be assumed in general. To calculate the radiative energy transport under these conditions, the population evolution equation must be evaluated explicitly, including all time-dependent terms. We develop a numerical method to solve the evolution equation for the atomic-level populations in a time-implicit way, keeping all time-dependent terms to first order. We show that the linear approximation of the time dependence of the populations can handle very large time steps without losing accuracy. We reproduce the benchmark solutions from earlier, well-established works in terms of non-LTE kinetic equilibrium solutions and typical ionization/recombination timescales in the solar chromosphere.

Keywords: Solar atmosphere, Theoretical techniques, Radiative magnetohydrodynamics, Recombination, Stellar chromospheres, Computational methods, Radiative transfer, Ionization, Spectroscopy, Radiative transfer simulations, Solar chromosphere, Stellar atmospheres
Large Amplitude Switchback Turbulence: Possible Magnetic Velocity Alignment Structures. Switchbacks are widely acknowledged phenomena observed by the Parker Solar Probe and appear to occur in patches. Previous studies focused on the fluctuations at the magnetic reversals. However, the nature of the fluctuations inside the switchbacks remains unknown. Here we utilize the magnetic field data and plasma data measured by the Parker Solar Probe in the first four encounters. We investigate the fluctuations in the switchback intervals of 100 s with ${B}_{R}\gt 0$ at every instant and compare them to the fluctuations in the nonswitchback intervals of 100 s with ${\theta }_{\mathrm{RB}}\gt 160^\circ $ at every instant. We calculate normalized cross-helicity ${\sigma }_{{\rm{c}}}$ , normalized residual energy ${\sigma }_{{\rm{r}}}$ , correlation coefficient Cvb between ${\boldsymbol{\delta }}{{\boldsymbol{v}}}_{{\rm{A}}}$ and ${\boldsymbol{\delta }}{\boldsymbol{v}}$ , Alfvén ratio rA, and the amplitude of magnetic and kinetic fluctuations. We find that the switchback intervals exhibit a distribution of ${\sigma }_{{\rm{c}}}$ similar with the nonswitchback intervals. However, the rA of switchback intervals is around 0.35, while the nonswitchback intervals have rA around 0.65, indicating the fluctuations in the switchbacks are more magnetically dominated. We also find that the distribution pattern of pixel average amplitude of both ${\boldsymbol{\delta }}{{\boldsymbol{v}}}_{{\rm{A}}}$ and ${\boldsymbol{\delta }}{\boldsymbol{v}}$ of switchback intervals in the Cvb- ${\sigma }_{{\rm{r}}}$ plane show a vertical stripe feature at ${C}_{\mathrm{vb}}\gt 0.8$ , illustrating the possible magnetically dominant magnetic-velocity alignment structure. These results will help us to understand the nature and the formation of the switchback turbulence.

Keywords: Interplanetary turbulence, Solar wind
Progenitor Dependence of Hadron-quark Phase Transition in Failing Core-collapse Supernovae. We study the consequences of a hadron-quark phase transition (PT) in failing core-collapse supernovae (CCSNe) that give birth to stellar-mass black holes (BH). We perform a suite of neutrino-transport general-relativistic hydrodynamic simulations in spherical symmetry with 21 progenitor models and a hybrid equation of state (EoS) including hadrons and quarks. We find that the effect of the PT on the CCSN postbounce dynamics is a function of the bounce compactness parameter ${\xi }_{2.2}$ . For ${\xi }_{2.2}\gtrsim 0.24$ , the PT leads to a second dynamical collapse of the protocompact star (PCS). While BH formation starts immediately after this second collapse for models with ${\xi }_{2.2}\gtrsim 0.51$ , the PCS experiences a second bounce and oscillations for models with $0.24\lesssim {\xi }_{2.2}\lesssim 0.51$ . These models emit potent oscillatory neutrino signals with a period of ∼1 ms for tens of milliseconds after the second bounce, which can be a strong indicator of the PT in failing CCSNe if detected in the future. However, no shock revival occurs and BH formation inevitably takes place in our spherically symmetric simulations. Furthermore, via a diagram of mass-specific entropy evolution of the PCS, the progenitor dependence can be understood through the appearance of a third family of compact stars emerging at large entropy induced by the PT.

Keywords: Supernova neutrinos, Nuclear astrophysics, Stellar mass black holes, Core-collapse supernovae