Sazuna/UAT_keywords huggingface dataset:
A Comparison of Multiphase Magnetic Field Tracers in a High Galactic Latitude Region of the Filamentary Interstellar Medium. Understanding how the Galactic magnetic field threads the multiphase interstellar medium (ISM) remains a considerable challenge, as different magnetic field tracers probe dissimilar phases and field components. We search for evidence of a common magnetic field shared between the ionized and neutral ISM by comparing 1.4 GHz radio continuum polarization and H I line emission from the Galactic Arecibo L-Band Feed Array Continuum Transit Survey (GALFACTS) and Galactic Arecibo L-Band Feed Array H I (GALFA-H I) survey, respectively. We compute the polarization gradient of the continuum emission and search for associations with diffuse/translucent H I structures. The polarization gradient is sensitive to changes in the integrated product of the thermal electron density and line-of-sight field strength (B ∥) in warm ionized gas, while narrow H I structures highlight the plane-of-sky field orientation in cold neutral gas. We identified one region in the high Galactic latitude Arecibo sky, G216+26 centered on (ℓ, b) ~ (216°, +26°), containing filaments in the polarization gradient that are aligned with narrow H I structures roughly parallel to the Galactic plane. We present a comparison of multiphase observations and magnetic field tracers of this region, demonstrating that the warm ionized and cold neutral media are connected likely via a common magnetic field. We quantify the physical properties of a polarization gradient filament associated with Hα emission, measuring a line-of-sight field strength B ∥ = 6 ± 4 μG and a plasma beta $\beta ={2.1}_{-2.1}^{+3.1}$ . We discuss the lack of widespread multiphase magnetic field alignments and consider whether this region is associated with a short-timescale or physically rare phenomenon. This work highlights the utility of multitracer analyses for understanding the magnetized ISM.

Keywords: Interstellar phases, Interstellar filaments, Milky Way magnetic fields, Astrophysical magnetism, Interstellar magnetic fields, Interstellar medium
A Systematic Exploration of Kilonova Candidates from Neutron Star Mergers during the Third Gravitational-wave Observing Run. We present a comprehensive analysis of 653 optical candidate counterparts reported during the third gravitational-wave (GW) observing run. Our sample concentrates on candidates from the 15 events (published in GWTC-2, GWTC-3, or not retracted on GraceDB) that had a &gt;1% chance of including a neutron star in order to assess their viability as true kilonovae. In particular, we leverage tools available in real time, including pre-merger detections and cross-matching with catalogs (i.e., point-source, variable-star, quasar and host-galaxy redshift data sets), to eliminate 65% of candidates in our sample. We further employ spectroscopic classifications, late-time detections, and light-curve behavior analyses and conclude that 66 candidates remain viable kilonovae. These candidates lack sufficient information to determine their classifications, and the majority would require luminosities greater than that of AT 2017gfo. Pre-merger detections in public photometric survey data and comparison of cataloged host-galaxy redshifts with the GW event distances are critical to incorporate into vetting procedures, as these tools eliminated &gt;20% and &gt;30% of candidates, respectively. We expect that such tools that leverage archival information will significantly reduce the strain on spectroscopic and photometric follow-up resources in future observing runs. Finally, we discuss the critical role prompt updates from GW astronomers to the EM community play in reducing the number of candidates requiring vetting.

Keywords: Gravitational wave astronomy, Neutron stars
Polarization of Rotationally Oblate Self-luminous Exoplanets with Anisotropic Atmospheres. The young self-luminous giant exoplanets are expected to be oblate in shape, owing to the high rotational speeds observed for some objects. Similar to the case of brown dwarfs, the thermal emission from these planets should be polarized by scatterings of molecules and condensate cloud particles, and the rotation-induced asymmetry of the planet's disk would yield to net nonzero detectable polarization. Considering an anisotropic atmosphere, we present here a three-dimensional approach to estimating the disk-averaged polarization that arises due to the oblateness of the planets. We solve the multiple-scattering vector radiative transfer equations at each location on the planet's disk and calculate the local Stokes vectors, and then calculate the disk-integrated flux and linear polarization. For a cloud-free atmosphere, the polarization signal is observable only in the visible wavelength region. However, the presence of clouds in the planetary atmospheres leads to a detectable amount of polarization in the infrared wavelength region where the planetary thermal emission peaks. Considering the different broadband filters of the SPHERE-IRDIS instrument of the Very Large Telescope, we present generic models for the polarization at different wavelength bands as a function of their rotation period. We also present polarization models for the exoplanets β Pic b and ROXs 42B b, as two representative cases that can guide future observations. Our insights into the polarization of young giant planets presented here would be useful for the upcoming polarimetric observations of the directly imaged planets.

Keywords: Spectropolarimetry, Exoplanets, Atmospheric clouds, Direct imaging, Polarimetry, Extrasolar gaseous giant planets, Exoplanet atmospheres
Resilience of Planetesimal Formation in Weakly Reinforced Pressure Bumps. The discovery that axisymmetric dust rings are ubiquitous in protoplanetary disks has provoked a flurry of research on the role of pressure bumps in planet formation. High-resolution simulations by our group have shown that even a modest bump can collect enough dust to trigger planetesimal formation by the streaming instability. In this work, we probe the limits of planetesimal formation when the external source of pressure bump reinforcement is extremely weak. We conduct simulations of radially elongated shearing boxes to capture the entire bump, which is generated and maintained over some timescale ${t}_{\mathrm{reinf}}$ by a Newtonian relaxation scheme. We find that planetesimal formation is extremely resilient for centimeter-sized grains. We reduced the strength of reinforcement by up to a factor of 100 and the location and initial masses of planetesimals were essentially unaffected. However, we do find that strong reinforcement causes much faster pebble drift compared to the standard pebble drift rates. The resulting larger pebble flux enhances the planetesimal growth rate by pebble accretion. We hypothesize that, to sustain the bump, our code has to extract angular momentum (the strength of this negative torque depends on ${t}_{\mathrm{reinf}}$ ), and some of this torque is transferred to the particles, causing them to drift faster for a stronger torque (i.e., smaller ${t}_{\mathrm{reinf}}$ ). Since any physical process that sustains a pressure bump must do so by torquing the gas, we conjecture that the effect on pebble drift is a real phenomenon, motivating further work with physically realistic sources to generate the bump.

Keywords: Planetary system formation, Protoplanetary disks, Planetesimals, Exoplanet formation, Planet formation
Detecting Preheating in Protoclusters with Lyα Forest Tomography. Studies of low-redshift galaxy clusters suggest the intracluster medium (ICM) has experienced nongravitational heating during the formation phase of the clusters. Using simple phenomenological heating prescriptions, we simulate the effect of this preheating of the nascent ICM in galaxy protoclusters and examine its effect on Lyα forest tomographic maps. We analyze a series of cosmological zoom-in simulations of protoclusters within the framework of the Lyα transmission-dark matter (DM) density distribution. We find that the more energy is injected into the proto-ICM at z = 3, the more the distribution at high DM density tilts toward higher Lyα transmission. This effect has been confirmed in both low-resolution simulations adopting a preheating scheme based on entropy floors, as well as in higher-resolution simulations with another scheme based on energy floors. The evolution of the slope of this distribution is shown to vary with redshift. The methodology developed here can be applied to current and upcoming Lyα forest tomographic survey data to help constrain feedback models in galaxy protoclusters.

Keywords: Galaxy clusters, Intracluster medium, Lyman alpha forest
Misaligned Rotations of the Envelope, Outflow, and Disks in the Multiple Protostellar System of VLA 1623-2417: FAUST. III. We report a study of the low-mass Class 0 multiple system VLA 1623AB in the Ophiuchus star-forming region, using H13CO+ (J = 3-2), CS (J = 5-4), and CCH (N = 3-2) lines as part of the ALMA Large Program FAUST. The analysis of the velocity fields revealed the rotation motion in the envelope and the velocity gradients in the outflows (about 2000 au down to 50 au). We further investigated the rotation of the circumbinary VLA 1623A disk, as well as the VLA 1623B disk. We found that the minor axis of the circumbinary disk of VLA 1623A is misaligned by about 12° with respect to the large-scale outflow and the rotation axis of the envelope. In contrast, the minor axis of the circumbinary disk is parallel to the large-scale magnetic field according to previous dust polarization observations, suggesting that the misalignment may be caused by the different directions of the envelope rotation and the magnetic field. If the velocity gradient of the outflow is caused by rotation, the outflow has a constant angular momentum and the launching radius is estimated to be 5-16 au, although it cannot be ruled out that the velocity gradient is driven by entrainments of the two high-velocity outflows. Furthermore, we detected for the first time a velocity gradient associated with rotation toward the VLA 16293B disk. The velocity gradient is opposite to the one from the large-scale envelope, outflow, and circumbinary disk. The origin of its opposite gradient is also discussed.

Keywords: Interstellar molecules, Stellar jets, Astrochemistry, Young stellar objects, Star formation, Interstellar medium, Circumstellar disks, Protostars
On the Fast Radio Burst and Persistent Radio Source Populations. The first fast radio burst (FRB) to be precisely localized was associated with a luminous persistent radio source (PRS). Recently, a second FRB/PRS association was discovered for another repeating source of FRBs. However, it is not clear what makes FRBs or PRS or how they are related. We compile FRB and PRS properties to consider the population of FRB/PRS sources. We suggest a practical definition for PRS as FRB associations with luminosity greater than 1029 erg s-1 Hz-1 that are not attributed to star formation activity in the host galaxy. We model the probability distribution of the fraction of FRBs with PRS for repeaters and nonrepeaters, showing there is not yet evidence for repeaters to be preferentially associated with PRS. We discuss how FRB/PRS sources may be distinguished by the combination of active repetition and an excess dispersion measure local to the FRB environment. We use CHIME/FRB event statistics to bound the mean per-source repetition rate of FRBs to be between 25 and 440 yr-1. We use this to provide a bound on the density of FRB-emitting sources in the local universe of between 2.2 × 102 and 5.2 × 104 Gpc-3 assuming a pulsar-like beamwidth for FRB emission. This density implies that PRS may comprise as much as 1% of compact, luminous radio sources detected in the local universe. The cosmic density and phenomenology of PRS are similar to that of the newly discovered, off-nuclear "wandering" active galactic nuclei (AGN). We argue that it is likely that some PRS have already been detected and misidentified as AGN.

Keywords: Magnetars, Radio bursts, Radio source counts
Multimessenger Constraints on Magnetic Fields in Merging Black Hole-Neutron Star Binaries. The LIGO-Virgo-KAGRA Collaboration recently detected gravitational waves (GWs) from the merger of black hole-neutron star (BHNS) binary systems GW200105 and GW200115. No coincident electromagnetic (EM) counterparts were detected. While the mass ratio and BH spin in both systems were not sufficient to tidally disrupt the NS outside the BH event horizon, other, magnetospheric mechanisms for EM emission exist in this regime and depend sensitively on the NS magnetic field strength. Combining GW measurements with EM flux upper limits, we place upper limits on the NS surface magnetic field strength above which magnetospheric emission models would have generated an observable EM counterpart. We consider fireball models powered by the black hole battery mechanism, where energy is output in gamma rays over ≲1 s. Consistency with no detection by Fermi-GBM or INTEGRAL SPI-ACS constrains the NS surface magnetic field to ≲1015 G. Hence, joint GW detection and EM upper limits rule out the theoretical possibility that the NSs in GW200105 and GW200115, and the putative NS in GW190814, retain dipolar magnetic fields ≳1015 G until merger. They also rule out formation scenarios where strongly magnetized magnetars quickly merge with BHs. We alternatively rule out operation of the BH-battery-powered fireball mechanism in these systems. This is the first multimessenger constraint on NS magnetic fields in BHNS systems and a novel approach to probe fields at this point in NS evolution. This demonstrates the constraining power that multimessenger analyses of BHNS mergers have on BHNS formation scenarios, NS magnetic field evolution, and the physics of BHNS magnetospheric interactions.

Keywords: Gravitational wave astronomy, Neutron stars, Gamma-ray sources, Magnetic fields
Strong [O III] λ5007 Emission-line Compact Galaxies in LAMOST DR9: Blueberries, Green Peas, and Purple Grapes. Green Pea and Blueberry galaxies are well known for their compact size, low mass, strong emission lines, and analogs to high-z Lyα-emitting galaxies. In this study, 1547 strong [O III] λ5007 emission-line compact galaxies with 1694 spectra are selected from LAMOST DR9 at the redshift range from 0.0 to 0.59. According to the redshift distribution, these samples can be separated into three groups: Blueberries, Green Peas, and Purple Grapes. Optical [Mg II] λ2800 line feature, BPT diagram, multiwavelength spectral energy distribution (SED) fitting, mid-IR (MIR) color, and MIR variability are deployed to identify 23 active galactic nucleus candidates from these samples, which are excluded for the following star formation rate (SFR) discussions. We perform the multiwavelength SED fitting with GALEX UV and WISE MIR data. Color excess from the Balmer decrement shows that these strong [O III] λ5007 emission-line compact galaxies are not highly reddened. The stellar mass of the galaxies is obtained by fitting LAMOST calibrated spectra with the emission lines masked. We find that the SFR is increasing with the increase of redshift, while for the sources within the same redshift bin the SFR increases with mass with a similar slope to the star-forming main sequence. These samples have a median metallicity of 12 + log(O/H) of 8.10. The metallicity increases with mass, and all the sources are below the mass-metallicity relation. The direct-derived T  e -based metallicity from the [O III] λ4363 line agrees with the empirical N2-based empirical gas-phase metallicity. Moreover, these compact strong [O III] λ5007 lines are mostly in a less dense environment.

Keywords: Compact galaxies
Spectroastrometry and Reverberation Mapping: The Mass and Geometric Distance of the Supermassive Black Hole in the Quasar 3C 273. The quasar 3C 273 has been observed with infrared spectroastrometry (SA) of the broad Paα line and optical reverberation mapping (RM) of the broad Hβ line. SA delivers information about the angular size and structure of the Paα broad-line region (BLR), while RM delivers information about the physical size and structure of the Hβ BLR. Based on the fact that the two BLRs share the mass of the supermassive black hole (SMBH) and viewing inclination, a combination of SA and velocity-resolved RM (SARM) thereby allows us to simultaneously determine the SMBH mass and geometric distance through dynamically modeling the two BLRs. We construct a suite of dynamical models with different geometric configurations and apply a Bayesian approach to obtain the parameter inferences. Overall the obtained masses and distances are insensitive to specific BLR configurations but more or less depend on parameterizations of the vertical distributions. The most probable model, chosen in light of the Bayes factor, yields an angular-size distance $\mathrm{log}({D}_{{\rm{A}}}/\mathrm{Mpc})={2.83}_{-0.28}^{+0.32}$ and an SMBH mass $\mathrm{log}({M}_{\bullet }/{M}_{\odot })={9.06}_{-0.27}^{+0.21}$ , which agree with the relationships between SMBH masses and bulge properties. The BLRs have an inclination of ${5}_{-1}^{+1}$ degrees, consistent with that of the large-scale jet in 3C 273. Our approach reinforces the capability of SARM analysis to measure SMBH masses and distances of active galactic nuclei and quasars even though SA and RM observations are undertaken with different emission lines and/or in different periods.

Keywords: Supermassive black holes, Quasars, Reverberation mapping, Active galaxies, Astrometry
A Sudden Period of High Activity from Repeating Fast Radio Burst 20201124A. The repeating FRB 20201124A was first discovered by CHIME/FRB in November of 2020, after which it was seen to repeat a few times over several months. It entered a period of high activity in April of 2021, at which time several observatories recorded tens to hundreds more bursts from the source. These follow-up observations enabled precise localization and host-galaxy identification. In this paper, we report on the CHIME/FRB-detected bursts from FRB 20201124A, including their best-fit morphologies, fluences, and arrival times. The large exposure time of the CHIME/FRB telescope toward the location of this source allows us to constrain its rates of activity. We analyze the repetition rates over different spans of time, constraining the rate prior to discovery to &lt;3.4 day-1 (at 3σ), and demonstrate a significant change in the event rate following initial detection. Lastly, we perform a maximum-likelihood estimation of a power-law luminosity function, finding a best-fit index α = -4.6 ± 1.3 ± 0.6, with a break at a fluence threshold of ${F}_{\min }\sim 16.6$ Jy ms, consistent with the fluence completeness limit of the observations. This index is consistent within uncertainties with those of other repeating FRBs for which it has been determined.

Keywords: Radio bursts, Radio transient sources
The Paschen Jump as a Diagnostic of the Diffuse Nebular Continuum Emission in Active Galactic Nuclei. Photoionization modeling of active galactic nuclei (AGN) predicts that diffuse continuum (DC) emission from the broad-line region makes a substantial contribution to the total continuum emission from ultraviolet through near-infrared wavelengths. Evidence for this DC component is present in the strong Balmer jump feature in AGN spectra, and possibly from reverberation measurements that find longer lags than expected from disk emission alone. However, the Balmer jump region contains numerous blended emission features, making it difficult to isolate the DC emission strength. In contrast, the Paschen jump region near 8200 Å is relatively uncontaminated by other strong emission features. Here, we examine whether the Paschen jump can aid in constraining the DC contribution, using Hubble Space Telescope Space Telescope Imaging Spectrograph spectra of six nearby Seyfert 1 nuclei. The spectra appear smooth across the Paschen edge, and we find no evidence of a Paschen spectral break or jump in total flux. We fit multicomponent spectral models over the range 6800-9700 Å and find that the spectra can still be compatible with a significant DC contribution if the DC Paschen jump is offset by an opposite spectral break resulting from blended high-order Paschen emission lines. The fits imply DC contributions ranging from ~10% to 50% at 8000 Å, but the fitting results are highly dependent on assumptions made about other model components. These degeneracies can potentially be alleviated by carrying out fits over a broader wavelength range, provided that models can accurately represent the disk continuum shape, Fe II emission, high-order Balmer line emission, and other components. *Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with programs 8136, 8479, 14121, 14744, 15124, and 15413.

Keywords: Seyfert galaxies, Active galactic nuclei, Spectroscopy
Investigating the Observational Properties of Type Ib Supernova SN 2017iro. We report results of optical imaging and low-resolution spectroscopic monitoring of supernova (SN) 2017iro that occurred in the nearby (~31 Mpc) galaxy NGC 5480. The He I λ5876 feature present in the earliest spectrum (-7 days) classified it as a Type Ib SN. The follow-up observations span from -7 to +266 days with respect to the B-band maximum. With a peak absolute magnitude in V band M  V  = -17.76 ± 0.15 mag and bolometric luminosity log10 L = 42.39 ± 0.09 erg s-1, SN 2017iro is a moderately luminous Type Ib SN. The overall light-curve evolution of SN 2017iro is similar to that of SN 2012au and SN 2009jf during the early (up to ~100 days) and late phases (&gt;150 days), respectively. The line velocities of both Fe II λ5169 and He I λ5876 are ~9000 km s-1 near the peak. The analysis of the nebular phase spectrum (~+209 days) indicates an oxygen mass of ~0.35 M ⊙. The smaller [O I]/[Ca II] flux ratio of ~1 favors a progenitor with a zero-age main-sequence mass in the range ~13-15 M ⊙, most likely in a binary system, similar to the case of iPTF13bvn. The explosion parameters are estimated by applying different analytical models to the quasi-bolometric light curve of SN 2017iro. 56Ni mass synthesized in the explosion has a range of ~0.05-0.10 M ⊙, ejecta mass ~1.4-4.3 M ⊙, and kinetic energy ~(0.8-1.9) × 1051 erg.

Keywords: Type Ib supernovae, Supernovae, Core-collapse supernovae