adsabs/SciX_UAT_keywords huggingface dataset:
Identification of Two Distinct Electron Populations in an Impulsive Solar Energetic Electron Event

We examine the release times of energetic electrons in the 2001 April 25 event. An M2.7 flare occurred on 2001 April 25, from AR 09433, located at N18W09. The flare was observed in X-rays by GOES and the Yohkoh spacecraft. The Yohkoh observation also included hard X-ray (HXR) images for all four energy channels: L, M1, M2, and H. We use Yohkoh observation times as a proxy for the release time of energetic electrons that propagated downward, which are responsible for the HXRs. In situ >∼25 keV electrons were observed by the Wind spacecraft. For these electrons, we obtain the release time at the Sun using the recently developed Fractional Velocity Dispersion Analysis method. We find that the release times of outward-propagating energetic electrons are clearly delayed from those that propagated downward. Furthermore, these delayed releases are energy dependent. The implication of this delay on the underlying acceleration and trapping process of the >∼25 keV electrons at solar flares is discussed.

Keywords: solar energetic particles; solar flares; solar magnetic reconnection
A Universal Fundamental Plane and the Mdyn-M⋆ Relation for Galaxies with CALIFA and MaNGA

We use the stellar kinematics for 2458 galaxies from the MaNGA survey to explore a universal fundamental plane (UFP) described by the equation $\mathrm{log}({{\rm{\Upsilon }}}_{e})=\mathrm{log}({S}_{0.5}^{2})-\mathrm{log}({I}_{e})-\mathrm{log}({R}_{e})+C$ , defined by the logarithms of effective radius, Re; the surface brightness within Re, Ie; the dynamical mass-to-light ratio within Re, Ye; and the total velocity parameter at Re, ${S}_{K}^{2}={{KV}}_{{R}_{e}}^{2}+{\sigma }_{{\star }_{e}}^{2}$ , where ${V}_{{R}_{e}}$ is the rotation velocity and ${\sigma }_{{\star }_{e}}$ is the velocity dispersion. The surface brightness is within Re, Ie, and the dynamical mass-to-light ratio is within Re, ϒe. We use sophisticated Schwarzschild dynamical models for a subsample of 300 galaxies from the CALIFA survey to calibrate the universal fundamental plane. This calibration allows us to propose both (i) a parameterization to estimate the difficult-to-measure averaged dynamical mass-to-light ratio within Re, ${{\rm{\Upsilon }}}_{e}^{\mathrm{fit}}$ , once the internal kinematics, surface brightness, and effective radius are known; and (ii) a new, more robust dynamical mass proxy consistent with dynamical models within 0.09 dex. We reproduce the relation between the dynamical mass and the stellar mass in the inner regions of galaxies with lower scatter. We use the estimated ${{\rm{\Upsilon }}}_{e}^{\mathrm{fit}}$ from our analysis to explore the UFP with the MaNGA data set. We find that all galaxies, from spheroids to disks, follow the UFP with a scatter significantly smaller (0.05 dex) than the one reported for the fundamental plane (∼0.09 dex) and comparable with Tully-Fisher studies (∼0.05 dex), but for a wider range of galaxy types. We also confirm that spheroidal and spiral galaxies follow the same M⋆-S0.5 scaling relation, with lower scatter than the ${M}_{\star }\mbox{--}{V}_{{R}_{e}}$ and ${M}_{\star }\mbox{--}{\sigma }_{{\star }_{e}}$ ones, which is in agreement with previous studies found in the literature.

Keywords: galaxies; early-type galaxies; late-type galaxies; scaling relations; galaxy kinematics
GOALS-JWST: Hidden Star Formation and Extended PAH Emission in the Luminous Infrared Galaxy VV 114

James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) images of the luminous infrared (IR) galaxy VV 114 are presented. This redshift ~0.020 merger has a western component (VV 114W) rich in optical star clusters and an eastern component (VV 114E) hosting a luminous mid-IR nucleus hidden at UV and optical wavelengths by dust lanes. With MIRI, the VV 114E nucleus resolves primarily into bright NE and SW cores separated by 630 pc. This nucleus comprises 45% of the 15 μm light of VV 114, with the NE and SW cores having IR luminosities, L IR(8 - 1000 μm) ~ 8 ± 0.8 × 1010 L ⊙ and ~ 5 ± 0.5 × 1010 L ⊙, respectively, and IR densities, ΣIR ≳ 2 ± 0.2 × 1013 L ⊙ kpc-2 and ≳ 7 ± 0.7 × 1012 L ⊙ kpc-2, respectively-in the range of ΣIR for the Orion star-forming core and the nuclei of Arp 220. The NE core, previously speculated to have an active galactic nucleus (AGN), has starburst-like mid-IR colors. In contrast, the VV 114E SW core has AGN-like colors. Approximately 40 star-forming knots with L IR ~ 0.02-5 × 1010 L ⊙ are identified, 28% of which have no optical counterpart. Finally, diffuse emission accounts for 40%-60% of the mid-IR emission. Mostly notably, filamentary polycyclic aromatic hydrocarbon (PAH) emission stochastically excited by UV and optical photons accounts for half of the 7.7 μm light of VV 114. This study illustrates the ability of JWST to detect obscured compact activity and distributed PAH emission in the most extreme starburst galaxies in the local universe.

Keywords: active galaxies; galaxy nuclei; luminous infrared galaxies; star forming regions
Rubin Observatory LSST Transients and Variable Stars Roadmap

The Vera C. Rubin Legacy Survey of Space and Time (LSST) holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey's first light.

Keywords: telescopes; microlensing event rate; binary stars; exoplanets; young stellar objects; supernovae; blazars; tidal disruption; pulsating variable stars; brown dwarfs
Evolving Morphology of Resolved Stellar Einstein Rings

We consider strong gravitational lensing by nearby stars. Using our wave-optical treatment of lensing phenomena, we study Einstein rings that may form around nearby stellar lenses. It is remarkable that these rings are bright and large enough to be detected and resolved by existing instruments. Such lensing events have durations of hours or days, with peak light amplification lasting for several minutes. Many such events may be predicted using the Gaia astrometric catalog. Serendipitous discoveries are also possible. Fortuitous alignments can be used to confirm or discover and study exoplanets. For lenses that have dense stellar regions in their background, these events may occur several time a year, warranting their continuous or recurrent monitoring. Resolved imaging and spectroscopy of the evolving morphology of an Einstein ring offers knowledge about both the lens and the source. The angular size of the Einstein ring amounts to a direct measurement of the lens mass. The changing orientation of the major and minor images of the source offers astrometric information related to the mutual orientation of the objects. The event duration, when the full ring is present, helps to determine the source's size. The sky position of planetary lensing events constrains the planet's orbit. Spectroscopy of the ring allows for direct investigations of the source. The frequency and predictability of these events and the wealth of information that can be obtained by imaging motivate observational campaigns using existing facilities and/or construction of new instruments dedicated to the search and study of Einstein rings that are forming around nearby stars. As a specific example, we consider a predicted 2028 lensing of a red giant by α Centauri A and discuss the relevant science campaign.

Keywords: gravitational lensing
Correlation Analysis between OJ 287 Radio Jet Observables

We collected the archival data of blazar OJ 287 from heterogeneous very long baseline interferometry monitoring programs at 2.3, 8.6, 15, and 43 GHz. The data reduction and observable extraction of those multiband, multiepoch observations are batch-processed consistently with our automated pipeline. We present the multivariate correlation analysis on the observables at each band. We employ the cross-correlation function to search the correlations and the Monte Carlo technique to verify the certainty of correlations. Several correlations are found. The foremost findings are the correlations between the core flux density and the jet position angles on different scales, which validated the plausible predictions of the jet with precession characteristics. Meanwhile, there is a variation in the offset between the core electric vector position angle and the inner-jet position angle over time at 15 and 43 GHz.

Keywords: active galactic nuclei; blazars; radio jets; relativistic aberration; relativistic jets; very long baseline interferometry
Influence of Biomass Emissions on Habitability, Biosignatures, and Detectability in Earth-like Atmospheres

We investigate the atmospheric responses of modeled hypothetical Earth-like planets in the habitable zone of the M-dwarf AD Leonis to reduced oxygen (O2), removed biomass ("dead" Earth), and varying carbon dioxide (CO2) and surface relative humidity (sRH). Results suggest large O2 differences between the reduced-O2 and dead scenarios in the lower but not the upper atmosphere layers. Ozone (O3) and nitrous oxide (N2O) also show this behavior. Methane depends on hydroxyl (OH), its main sink. Abiotic production of N2O occurs in the upper layers. Chloromethane (CH3Cl) decreases everywhere on decreasing biomass. Changing CO2 (from ×1 to ×100 present atmospheric levels (PALs)) and sRH (from 0.1% to 100%) does not influence CH3Cl as much as lowering biomass. Therefore, CH3Cl can be considered a good biosignature. Changing sRH and CO2 has a greater influence on temperature than changing O2 or biomass alone. Changing the biomass produces an ∼6 km effective height in transmission compared with changing CO2 and sRH (∼25 km). In transmission O2 is discernible at 0.76 μm for >0.1 PAL. The O3 9.6 μm band is weak for the low-O2 runs and difficult to discern from dead Earth; however O3 at 0.3 μm could serve as an indicator to distinguish between reduced-O2 and dead Earth. The spectral features of N2O and CH3Cl correspond to effective heights of a few kilometers. CH4 could be detectable tens of parsecs away with the Extremely Large Telescope except for the 10-4 and 10-6 PAL O2 scenarios. O2 is barely detectable for the 1 PAL O2 case and unfeasible at lower abundances.

Keywords: exoplanet atmospheres
Stellar Half-mass Radii of 0.5 z < 2.3 Galaxies: Comparison with JWST/NIRCam Half-light Radii

We use CEERS JWST/NIRCam imaging to measure rest-frame near-IR light profiles of 435 M ⋆ > 1010 M ⊙ galaxies in the redshift range of 0.5 < z < 2.3. We compare the resulting rest-frame 1.5-2 μm half-light radii (R NIR) with stellar half-mass radii ( ${R}_{{{M}}_{\star }}$ ) derived with multicolor light profiles from CANDELS Hubble Space Telescope imaging. In general agreement with previous work, we find that R NIR and ${R}_{{{M}}_{\star }}$ are up to 40% smaller than the rest-frame optical half-light radius R opt. The agreement between R NIR and ${R}_{{{M}}_{\star }}$ is excellent, with a negligible systematic offset (<0.03 dex) up to z = 2 for quiescent galaxies and up to z = 1.5 for star-forming galaxies. We also deproject the profiles to estimate ${R}_{{{M}}_{\star },3{\rm{D}}}$ , the radius of a sphere containing 50% of the stellar mass. We present the R-M ⋆ distribution of galaxies at 0.5 < z < 1.5, comparing R opt, ${R}_{{{M}}_{\star }}$ , and ${R}_{{{M}}_{\star },3{\rm{D}}}$ . The slope is significantly flatter for ${R}_{{{M}}_{\star }}$ and ${R}_{{{M}}_{\star },3{\rm{D}}}$ compared to R opt, mostly due to downward shifts in size for massive star-forming galaxies, while ${R}_{{{M}}_{\star }}$ and ${R}_{{{M}}_{\star },3{\rm{D}}}$ do not show markedly different trends. Finally, we show rapid evolution of the size (R ∝ (1 + z)-1.7±0.1) of massive (M ⋆ > 1011 M ⊙) quiescent galaxies between z = 0.5 and z = 2.3, again comparing R opt, ${R}_{{{M}}_{\star }}$ , and ${R}_{{{M}}_{\star },3{\rm{D}}}$ . We conclude that the main tenets of the evolution of the size narrative established over the past 20 yr, based on rest-frame optical light profile analysis, still hold in the era of JWST/NIRCam observations in the rest-frame near-IR.

Keywords: galaxy evolution
Exploring the Maximum Magnitude versus Rate of Decline Relation for Novae in M31

The results of a two-decade-long R-band photometric survey of novae in M31 are presented. From these data, R-band light curves have been determined for 180 novae with data sufficient for estimating the peak brightness and subsequent rate of decline. The data show a weak correlation of peak brightness with fade rate consistent with the well-known maximum magnitude versus rate of decline (MMRD) relation. As generally appreciated for Galactic novae, the large scatter in the MMRD relation precludes its use in determining distances to individual novae. The novae at maximum light are distributed with standard deviation σ = 0.89 mag about a mean R-band absolute magnitude given by <M R > = ‑7.57 ± 0.07. The overall M31 luminosity distribution is in excellent agreement with that found for Galactic novae suggesting that the nova populations in M31 and the Galaxy are quite similar. The notion that all novae can be characterized by a standard luminosity 15 days after maximum light (M 15) is also explored. Surprisingly, the distribution of M 15 values is characterized by a standard deviation only slightly smaller than that for novae at maximum light and thus offers little promise for precise extragalactic distance determinations. A dozen faint and fast novae that are likely to be previously unidentified recurrent novae have been identified from their position in the MMRD plot and in the M 15 distribution.

Keywords: andromeda galaxy; cataclysmic variable stars; novae; recurrent novae; time domain astronomy
Early-type Host Galaxies of Type Ia Supernovae. II. Evidence for Luminosity Evolution in Supernova Cosmology

The most direct and strongest evidence for the presence of dark energy is provided by the measurement of galaxy distances using SNe Ia. This result is based on the assumption that the corrected brightness of SN Ia through the empirical standardization would not evolve with look-back time. Recent studies have shown, however, that the standardized brightness of SN Ia is correlated with host morphology, host mass, and local star formation rate (SFR), suggesting a possible correlation with stellar population property. To understand the origin of these correlations, we have continued our spectroscopic observations to cover most of the reported nearby early-type host galaxies. From high-quality (signal-to-noise ratio ∼175) spectra, we obtained the most direct and reliable estimates of population age and metallicity for these host galaxies. We find a significant correlation between SN luminosity (after the standardization) and stellar population age at a 99.5% confidence level. As such, this is the most direct and stringent test ever made for the luminosity evolution of SN Ia. Based on this result, we further show that the previously reported correlations with host morphology, host mass, and local SFR are most likely originated from the difference in population age. This indicates that the light-curve fitters used by the SNe Ia community are not quite capable of correcting for the population age effect, which would inevitably cause a serious systematic bias with look-back time. Notably, taken at face values, most of the Hubble residual used in the discovery of the dark energy appears to be affected by the luminosity evolution.

Keywords: type ia supernovae; observational cosmology; dark energy; early-type galaxies
θ1 Ori C as a Medieval Bully: A Possible Very Recent Ejection in the Trapezium

We use Gaia EDR3 astrometry to propose that a dynamical interaction between the multiple system θ1 Ori C and θ1 Ori F ejected the latter as a walkaway star ~1100 yr ago (without deceleration) or somewhat later (with a more likely deceleration included). It is unclear whether the final 3D velocity of θ1 Ori F will be large enough to escape the Orion nebula cluster.

Keywords: multiple stars; runaway stars; o stars; young star clusters; astrometry
The El Gordo Galaxy Cluster Challenges ΛCDM for Any Plausible Collision Velocity

El Gordo (ACT-CL J0102-4915) is an extraordinarily large and bright galaxy cluster collision. In a previous study, we found that El Gordo is in 6.2σ tension with the Λ cold dark matter (ΛCDM) standard model when assuming the nominal mass and infall velocity values from the hydrodynamical simulations of Zhang et al. (M 200 = 3.2 × 1015 M ⊙ and V infall = 2500 km s-1, respectively). The recent weak-lensing study of Kim et al. showed that the mass of El Gordo is actually ${2.13}_{-0.23}^{+0.25}\times {10}^{15}{M}_{\odot }$ . Here we explore the level of tension between El Gordo and ΛCDM for the new mass estimate, assuming several V infall values. We find that in order to reduce the tension below the 5σ level, the El Gordo subclusters should have V infall < 2300 km s-1 (V infall < 1800 km s-1 when considering the combined tension with the Bullet Cluster). To the best of our knowledge, the El Gordo hydrodynamical simulations conducted so far require V infall ≥ 2500 km s-1 to simultaneously reproduce its morphology and its high X-ray luminosity and temperature. We therefore conclude that El Gordo still poses a significant challenge to ΛCDM cosmology. Whether the properties of El Gordo can be reconciled with a lower V infall should be tested with new hydrodynamical simulations that explore different configurations of the interaction.

Keywords: galaxy clusters; large-scale structure of the universe; gravitation; dark matter
Carbon Abundances in Compact Galactic Planetary Nebulae: An Ultraviolet Spectroscopic Study with the Space Telescope Imaging Spectrograph (STIS)

We surveyed a sample of compact Galactic planetary nebulae (PNe) with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST) to determine their gas-phase carbon abundances. Carbon abundances in PNe constrain the nature of their asymptotic giant branch (AGB) progenitors, as well as cosmic recycling. We measured the carbon abundances, or the limits thereof, of 11 compact Galactic PNe, notably increasing the sample of Galactic PNe whose carbon abundance based on HST ultraviolet spectra is available. The dust content of most targets has been studied elsewhere from Spitzer spectroscopy; given the compact nature of the nebulae, both UV and IR spectra can be directly compared to study gas- and dust-phase carbon. We found that carbon-poor (C/O < 1) compact Galactic PNe have an oxygen-rich dust type, while their carbon-enhanced counterparts (C/O > 1) have carbon-rich dust, confirming the correlation between gas- and dust-phase carbon content that was known for Magellanic Cloud PNe. Based on models of expected final yields from AGB evolution, we interpret the majority of the carbon-poor PNe in this study as the progeny of ~1.1-1.2 M ⊙ stars that experienced some extra mixing on the red giant branch. They went through the AGB but did not go through the carbon star phase. Most PNe in this group have a bipolar morphology, possibly due to the presence of a subsolar companion. The carbon-enhanced PNe in our sample could be the progeny of stars in the ~1.5-2.5 M ⊙ range, depending on their original metallicity.

Keywords: planetary nebulae
An Untargeted Survey of the Rotational Properties of Main-belt Asteroids using the Transiting Exoplanet Survey Satellite (TESS)

We present photometric data for minor planets observed by the Transiting Exoplanet Survey Satellite during its Cycle 1 operations. In total, we extracted usable detections for 37,965 objects. We present an examination of the reliability of the rotation period and light-curve amplitudes derived from each object based upon the number of detections and the normalized Lomb-Scargle power of our period fitting and compare and contrast our results with previous similar works. We show that for objects with 200 or more photometric detections and a derived normalized, generalized Lomb-Scargle power greater than 0.2, we have an 85% confidence in that period; this encompasses 3492 rotation periods we consider to be highly reliable. We independently examine a series of periods first reported by Pál et al.; periods derived in both works found to have similar results should be considered reliable. Additionally, we demonstrate the need to properly account for the true proportion of slow rotators (P > 100 hr) when inferring shape distributions from sparse photometry.

Keywords: asteroids; surveys; asteroid rotation
Secondary Whistler and Ion-cyclotron Instabilities Driven by Mirror Modes in Galaxy Clusters

Electron cyclotron waves (whistlers) are commonly observed in plasmas near Earth and the solar wind. In the presence of nonlinear mirror modes, bursts of whistlers, usually called lion roars, have been observed within low magnetic field regions associated with these modes. In the intracluster medium (ICM) of galaxy clusters, the excitation of the mirror instability is expected, but it is not yet clear whether electron and ion cyclotron (IC) waves can also be present under conditions where gas pressure dominates over magnetic pressure (high β). In this work, we perform fully kinetic particle-in-cell simulations of a plasma subject to a continuous amplification of the mean magnetic field B (t) to study the nonlinear stages of the mirror instability and the ensuing excitation of whistler and IC waves under ICM conditions. Once mirror modes reach nonlinear amplitudes, both whistler and IC waves start to emerge simultaneously, with subdominant amplitudes, propagating in low- B regions, quasi-parallel to B (t). We show that the underlying source of excitation is the pressure anisotropy of electrons and ions trapped in mirror modes with loss-cone-type distributions. We also observe that IC waves play an essential role in regulating the ion pressure anisotropy at nonlinear stages. We argue that whistler and IC waves are a concomitant feature at late stages of the mirror instability even at high β, and therefore, expected to be present in astrophysical environments like the ICM. We discuss the implications of our results for collisionless heating and dissipation of turbulence in the ICM.

Keywords: plasma astrophysics; intracluster medium; galaxy clusters; extragalactic magnetic fields; high energy astrophysics