adsabs/SciX_UAT_keywords huggingface dataset:
The Spectacular Tidal Tails of Globular Cluster M3 (NGC 5272)

We provide a detailed analysis of the tidal tails of the globular cluster M3 (NGC 5272). We first discover clear extratidal structures with a slight S shape near the cluster. This inspires us to examine the existence of its long tidal tails. We highlight potential stream stars using the proper motions (PMs) of a model stream combined with the cluster's locus in a color-magnitude diagram (CMD). A 35° long leading tail and a 21° long trailing tail are successfully detected at the same time. Their corresponding overdensities can be recognized in CMD and PM space after subtracting the background. We estimate the stream width, star number density, and surface brightness for both tails, as well as the distance variation along the entire stream. We then verify the connection of M3 and the Svöl stream. Finally, we tabulate 11 member stars belonging to the M3 tidal stream with available spectroscopic observations.

Keywords: globular star clusters; stellar streams; milky way stellar halo
The Hough Stream Spotter: A New Method for Detecting Linear Structure in Resolved Stars and Application to the Stellar Halo of M31

Stellar streams from globular clusters (GCs) offer constraints on the nature of dark matter and have been used to explore the dark matter halo structure and substructure of our Galaxy. Detection of GC streams in other galaxies would broaden this endeavor to a cosmological context, yet no such streams have been detected to date. To enable such exploration, we develop the Hough Stream Spotter (HSS), and apply it to the Pan-Andromeda Archaeological Survey (PAndAS) photometric data of resolved stars in M31's stellar halo. We first demonstrate that our code can re-discover known dwarf streams in M31. We then use the HSS to blindly identify 27 linear GC stream-like structures in the PAndAS data. For each HSS GC stream candidate, we investigate the morphologies of the streams and the colors and magnitudes of all stars in the candidate streams. We find that the five most significant detections show a stronger signal along the red giant branch in color-magnitude diagrams than spurious non-stream detections. Lastly, we demonstrate that the HSS will easily detect globular cluster streams in future Nancy Grace Roman Space Telescope data of nearby galaxies. This has the potential to open up a new discovery space for GC stream studies, GC stream gap searches, and for GC stream-based constraints on the nature of dark matter.

Keywords: galaxy dark matter halos; dark matter distribution; cold dark matter; globular star clusters; stellar streams; galaxy structure; galaxy kinematics; galaxy dynamics; galaxy stellar halos; andromeda galaxy
A Neutral Beam Model for High-energy Neutrino Emission from the Blazar TXS 0506+056

The IceCube collaboration reported an ∼3.5σ excess of 13 ± 5 neutrino events in the direction of the blazar TXS 0506+056 during an ∼6 month period in 2014-2015, as well as the (∼3σ) detection of a high-energy muon neutrino during an electromagnetic flare in 2017. We explore the possibility that the 2014-2015 neutrino excess and the 2017 multimessenger flare are both explained in a common physical framework that relies on the emergence of a relativistic neutral beam in the blazar jet due to interactions of accelerated cosmic rays (CRs) with photons. We demonstrate that the neutral beam model provides an explanation for the 2014-2015 neutrino excess without violating X-ray and γ-ray constraints and yields results consistent with the detection of one high-energy neutrino during the 2017 flare. If both neutrino associations with TXS 05065+056 are real, our model requires that (I) the composition of accelerated CRs is light, with a ratio of helium nuclei to protons ≳5; (II) a luminous external photon field (∼1046 erg s-1) variable (on yearlong timescales) is present; and (III) the CR injection luminosity, as well as the properties of the dissipation region (I.e., Lorentz factor, magnetic field, and size), vary on yearlong timescales.

Keywords: particle astrophysics; blazars; active galactic nuclei; cosmic rays; high-energy cosmic radiation; gamma-ray astronomy; neutrino astronomy; high energy astrophysics; jets
Discovery and Timing of Millisecond Pulsars in the Globular Cluster M5 with FAST and Arecibo

We report on a comprehensive multiwavelength study of the pulsars in the globular cluster (GC) M5, including the discovery of M5G, a new compact noneclipsing "black widow" pulsar. Thanks to the analysis of 34 yr of radio data taken with the Five-hundred-meter Aperture Spherical radio Telescope and Arecibo telescopes, we obtained new phase-connected timing solutions for four pulsars and improved those of the other three. These have resulted in, among other things, (a) much improved proper motions for five pulsars, with transverse velocities (relative to the cluster) that are smaller than their respective escape velocities; (b) 3σ and 1.5σ detections of Shapiro delays in M5F and M5D, respectively; and (c) greatly improved measurement of the periastron advance in M5B, whose value of $\dot{\omega }=0\buildrel{\circ}\over{.} 01361(6)$ implies that M5B is still likely to be a heavy ( ${m}_{p}={1.981}_{-0.088}^{+0.038}\,{M}_{\odot }$ ) neutron star. The binary pulsars M5D, M5E, and M5F are confirmed to be in low-eccentricity binary systems, the low-mass companions of which are newly identified to be He white dwarfs using Hubble Space Telescope data. Four pulsars are also found to be associated with X-ray sources. Similarly to the eclipsing pulsar M5C, M5G shows little or no nonthermal X-ray emission, indicative of weak synchrotron radiation produced by intrabinary shocks. All seven pulsars known in M5 have short spin periods (<8 ms), and five are in binary systems with low orbital eccentricities. These characteristics differ from the overall GC pulsar population but confirm the expectations for the pulsar population in a cluster with a small rate of stellar encounters per binary system.

Keywords: globular star clusters; radio pulsars; millisecond pulsars
Modeling the Transport of Relativistic Solar Protons along a Heliospheric Current Sheet during Historic GLE Events

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

Keywords: space weather; heliosphere; solar energetic particles; solar-terrestrial interactions; solar activity
Large-scale Dynamics of Winds Originating from Black Hole Accretion Flows. I. Hydrodynamics

Winds from black hole accretion flows are ubiquitous. Previous works mainly focus on the launching of wind on the accretion flow scale. It still remains unclear how far the winds can propagate outward and what their large-scale dynamics is. As the first paper of this series, we study the large-scale dynamics of thermal wind beyond accretion scales via analytical and numerical methods. Boundary conditions, which are crucial to our problem, are analyzed and presented based on small-scale simulations combined with observations of winds. Both black hole and galaxy potential are taken into account. For winds originating from hot accretion flows, we find that the wind can reach large scales. The radial profiles of velocity, density, and temperature can be approximated by ${V}_{r}\approx {V}_{r0},\rho \approx {\rho }_{0}{(r/{r}_{0})}^{-2}$ and $T\approx {T}_{0}{(r/{r}_{0})}^{-2(\gamma -1)}$ , where Vr0, ρ0, and T0 are the velocity, density, and temperature of winds at the boundary ${r}_{0}(\equiv {10}^{3}{r}_{g})$ , and γ is the polytropic index. During the outward propagation, the enthalpy and rotational energy compensate for the increase of gravitational potential. For thin disks, we find that because the Bernoulli parameter is smaller, winds cannot propagate as far as the hot winds, but stop at a certain radius where the Bernoulli parameter is equal to the potential energy. Before the winds stop, the profiles of dynamical quantities can also be approximated by the above relations. In this case, the rotational energy alone compensates for the increase in potential energy.

Keywords: high energy astrophysics; active galactic nuclei; black holes; astrophysical black holes; supermassive black holes; interdisciplinary astronomy; astrophysical fluid dynamics; hydrodynamics
Prompt X-Ray Emission from Fast Radio Bursts—Upper Limits with AstroSat

Fast radio bursts (FRBs) are short-lived (∼ms), energetic transients (having a peak flux density of ∼Jy) with no known prompt emission in other energy bands. We present results of a search for prompt X-ray emissions from 41 FRBs using the Cadmium Zinc Telluride Imager on AstroSat, which continuously monitors ∼70% of the sky. Our searches on various timescales in the 20-200 keV range, did not yield any counterparts in this hard X-ray band. We calculate upper limits on hard X-ray flux, in the same energy range and convert them to upper bounds for η: the ratio of X-ray to radio fluence of FRBs. We find η ≤ 108-10 for hard X-ray emission. Our results will help constrain the theoretical models of FRBs as the models become more quantitative and nearer, brighter FRBs are discovered.

Keywords: radio bursts; radio transient sources; x-ray bursts
The Milky Way Bulge Extra-tidal Star Survey: BH 261 (AL 3)

The Milky Way Bulge extra-tidal star survey is a spectroscopic survey with the goal of identifying stripped globular cluster stars from inner Galaxy clusters. In this way, an indication of the fraction of metal-poor bulge stars that originated from globular clusters can be determined. We observed and analyzed stars in and around BH 261, an understudied globular cluster in the bulge. From seven giants within the tidal radius of the cluster, we measured an average heliocentric radial velocity of <RV> = -61 ± 2.6 km s-1 with a radial velocity dispersion of <σ> = 6.1 ± 1.9 km s-1. The large velocity dispersion may have arisen from tidal heating in the cluster's orbit about the Galactic center, or because BH 261 has a high dynamical mass as well as a high mass-to-light ratio. From spectra of five giants, we measure an average metallicity of <[Fe/H]> = -1.1 ± 0.2 dex. We also spectroscopically confirm an RR Lyrae star in BH 261, which yields a distance to the cluster of 7.1 ± 0.4 kpc. Stars with 3D velocities and metallicities consistent with BH 261 reaching to ~0.°5 from the cluster are identified. A handful of these stars are also consistent with the spatial distribution of potential debris from models focusing on the most recent disruption of the cluster.

Keywords: stellar populations; galactic archaeology; milky way dynamics; galactic bulge; galaxy bulges; globular star clusters; stellar accretion
Chromospheric Resonances above Sunspots and Potential Seismological Applications

Oscillations in sunspot umbrae exhibit remarkable differences between the photosphere and chromosphere. We evaluate two competing scenarios proposed for explaining those observations: a chromospheric resonant cavity and waves traveling from the photosphere to upper atmospheric layers. We have employed numerical simulations to analyze the oscillations in both models. They have been compared with observations in the low (Na I D2) and high (He I 10830 Å) chromosphere. The nodes of the resonant cavity can be detected as phase jumps or power dips, although the identification of the latter is not sufficient to claim the existence of resonances. In contrast, phase differences between velocity and temperature fluctuations reveal standing waves and unequivocally prove the presence of an acoustic resonator above umbrae. Our findings offer a new seismic method to probe active region chromospheres through the detection of resonant nodes.

Keywords: solar chromosphere; sunspots; solar atmosphere; solar oscillations; computational methods; observational astronomy
VLT/X-Shooter Spectroscopy of Lyman Break Analogs: Direct-method O/H Abundances and Nitrogen Enhancements

We used Very Large Telescope/X-Shooter to target a sample of nearby analogs of Lyman break galaxies (LBGs). These Lyman break analogs are similar to the LBGs in many of their physical properties. We determine electron temperatures using the weak [O III] λ4363 emission line and determine the oxygen abundance (O/H) using the direct and strong-line methods. We show that the direct and strong-line abundances are consistent with established relations within ∼0.2 dex. The analogs have nitrogen-to-oxygen ratios (N/O) and ionization parameters (q) that are, on average, offset with respect to typical local galaxies but similar to galaxies at z ∼ 2 and other analogs. The N/O and q excesses correlate with the offsets observed in the strong-line ratios, again similar to z ∼ 2. The star formation rate surface densities are consistent with the high electron density and ionization, indicating that the interstellar medium (ISM) pressure is set by feedback from the starbursts. For a given O/H, the apparent N/O excess arises owing to the offset in O/H with respect to the local mass-metallicity relation. This can be explained by recent inflow of relatively metal-poor gas that lowers O/H while leaving N/O unchanged. The difficulties in determining even basic ISM parameters in these nearby analogs illustrate some of the challenges we face at much higher redshifts, where similar rest-frame optical diagnostics for large samples of galaxies can be accessed with the James Webb Space Telescope.

Keywords: starburst galaxies; h ii regions; galaxy abundances; lyman-break galaxies; galaxies
Chemical Abundances of Eight Highly-extincted Milky Way Planetary Nebulae

Low- and intermediate-mass (0.8 M ⊙ < M < 8 M ⊙) stars that evolve into planetary nebulae (PNe) play an important role in tracing and driving Galactic chemical evolution. Spectroscopy of PNe enables access to both the initial composition of their progenitor stars and products of their internal nucleosynthesis, but determining accurate ionic and elemental abundances of PNe requires high-quality optical spectra. We obtained new optical spectra of eight highly-extincted PNe with limited optical data in the literature using the Low Resolution Spectrograph 2 on the Hobby-Eberly Telescope. Extinction coefficients, electron temperatures and densities, and ionic and elemental abundances of up to 11 elements (He, N, O, Ne, S, Cl, Ar, K, Fe, Kr, and Xe) are determined for each object in our sample. Where available, astrometric data from Gaia eDR3 is used to kinematically characterize the probability that each object belongs to the Milky Way's thin disk, thick disk, or halo. Four of the PNe show kinematic and chemical signs of thin disk membership, while two may be members of the thick disk. The remaining two targets lack Gaia data, but their solar O, Ar, and Cl abundances suggest thin disk membership. Additionally, we report the detection of broad emission features from the central star of M 3-35. Our results significantly improve the available information on the nebular parameters and chemical compositions of these objects, which can inform future analyses. * Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Keywords: planetary nebulae; chemical abundances
Orbits for Eight Binaries

The subject of the present paper is the analysis of the orbital solutions for eight binaries: WDS 02402+0436 = HDS 347, WDS 02552+5950 = MLR 520, WDS 03119+6131 = HDS 407, WDS 04570+7350 = YSC 145, WDS 05202+4105 = HDS 701, WDS 06467+0822 = HDS 940AB, WDS 08259-1623 = HDS 1199, and WDS 22550+5132 = HU 785. Seven orbits are determined for the first time, and the remaining orbit is a revision. The five binaries are HDS, discovered during the Hipparcos mission, two binaries were discovered before, 1902 and 1974, and one binary was discovered afterwards, 2009. All measured separations are less than 1 arcsecond, and in most studied pairs they are less than 0.4 arcseconds. The number of measurements is relatively small, from 9 to 16, except for one pair which has only been measured six times so far. The median orbital period is 95.1 yr, the shortest period is 12.5 yr, and the longest period is 362.7 yr. In addition to the orbital elements, we also give absolute magnitudes, spectral types, estimates of the masses, dynamical parallaxes, and $(O-C)$ residuals in θ and ρ.

Keywords: fundamental parameters of stars; visual binary stars
Validation of Global EUV Wave MHD Simulations and Observational Techniques

Global EUV waves remain a controversial phenomenon more than 20 yr after their discovery by SOHO/EIT. Although consensus is growing in the community that they are most likely large-amplitude waves or shocks, the wide variety of observations and techniques used to identify and analyze them have led to disagreements regarding their physical properties and interpretation. Here, we use a 3D magnetohydrodynamic (MHD) model of the solar corona to simulate an EUV wave event on 2009 February 13 to enable a detailed validation of the various commonly used detection and analysis techniques of global EUV waves. The simulated event exhibits comparable behavior to that of a real EUV wave event, with similar kinematic behavior and plasma parameter evolution. The kinematics of the wave are estimated via visual identification and profile analysis, with both approaches providing comparable results. We find that projection effects can affect the derived kinematics of the wave, due to the variation in fast-mode wave speed with height in the corona. Coronal seismology techniques typically used for estimates of the coronal magnetic field are also tested and found to estimate fast-mode speeds comparable to those of the model. Plasma density and temperature variations of the wave front are also derived using a regularized inversion approach and found to be consistent with observed wave events. These results indicate that global waves are best interpreted as large-amplitude waves and that they can be used to probe the coronal medium using well-defined analysis techniques.

Keywords: solar corona; solar coronal mass ejections; solar coronal waves; solar magnetic fields; solar extreme ultraviolet emission; magnetohydrodynamical simulations
PAH Emission from Star-forming Galaxies in JWST Mid-infrared Imaging of the Lensing Cluster SMACS J0723.3-7327

The mid-infrared spectra of star-forming galaxies (SFGs) are characterized by characteristic broad polycyclic aromatic hydrocarbon (PAH) emission features at 3-20 μm. As these features are redshifted, they are predicted to dominate the flux at specific mid-infrared wavelengths, leading to substantial redshift-dependent color variations in broadband photometry. The advent of JWST for the first time allows the study of this effect for normal SFGs. Based on spectral energy distribution templates, we here present tracks in mid-infrared (4.4, 7.7, 10, 15, and 18 μm) color-color diagrams describing the redshift dependence of SFG colors. In addition, we present simulated color-color diagrams by populating these tracks using the cosmic star formation history and the star formation rate function. Depending on redshift, we find that SFGs stand out in the color-color diagrams by several magnitudes. We provide the first observational demonstration of this effect for galaxies detected in the JWST Early Release Observations of the field toward the lensing cluster SMACS J0723.3-7327. While the distribution of detected galaxies is consistent with the simulations, the numbers are substantially boosted by lensing effects. The PAH emitter with the highest spectroscopic redshift, detected in all bands, is a multiply imaged galaxy at z = 1.45. There is also a substantial number of cluster members that do not exhibit PAH emission except for one SFG at z = 0.38. Future wider-field observations will further populate mid-infrared color-color diagrams and provide insight into the evolution of typical SFGs.

Keywords: polycyclic aromatic hydrocarbons; galaxy photometry; galaxy colors; james webb space telescope
A Multiwavelength Study of the γ-Ray Binary Candidate HESS J1832-093

We investigate the nature of the unidentified very-high-energy γ-ray object, HESS J1832-093, in a multiwavelength context. Based on X-ray variability and spectral index ( ${{\rm{\Gamma }}}_{X}\sim \,1.5$ ), and its broadband spectrum, which was remarkably similar to that of HESS J0632+057—a confirmed γ-ray binary—HESS J1832-093 has been considered a strong γ-ray binary candidate in previous works. In this work, we provide further evidence for this scenario. We obtained a spectrum of its IR counterpart using Gemini/Flamingo, finding absorption lines that are usually seen in massive stars, in particular O stars. We also obtained a rather steep ATCA spectrum ( $\alpha =-{1.18}_{-0.88}^{+1.04}$ ), which is consistent with a γ-ray binary. Based on spatial-spectral analysis and variability search, we found that 4FGL J1832.9-0913 is possibly associated with SNR G22.7-0.2 rather than with HESS J1832-093 only.

Keywords: high mass x-ray binary stars; gamma-ray sources; spectroscopy; galactic radio sources; massive stars