adsabs/SciX_UAT_keywords huggingface dataset:
Correlation of Coronal Mass Ejection Shock Temperature with Solar Energetic Particle Intensity

Solar energetic particle (SEP) events have been observed by the Parker Solar Probe (PSP) spacecraft since its launch in 2018. These events include sources from solar flares and coronal mass ejections (CMEs). The IS⊙IS instrument suite on board PSP is measuring ions over energies from ∼ 20 keV nucleon‑1 to 200 MeV nucleon‑1 and electrons from ∼ 20 keV to 6 MeV. Previous studies sought to group CME characteristics based on their plasma conditions and arrived at general descriptions with large statistical errors, leaving open questions on how to properly group CMEs based solely on their plasma conditions. To help resolve these open questions, the plasma properties of CMEs have been examined in relation to SEPs. Here, we reexamine one plasma property, the solar wind proton temperature, and compare it to the proton SEP intensity in a region immediately downstream of a CME-driven shock for seven CMEs observed at radial distances within 1 au. We find a statistically strong correlation between proton SEP intensity and bulk proton temperature, indicating a clear relationship between SEPs and the conditions in the solar wind. Furthermore, we propose that an indirect coupling of SEP intensity to the level of turbulence and the amount of energy dissipation that results is mainly responsible for the observed correlation between SEP intensity and proton temperature. These results are key to understanding the interaction of SEPs with the bulk solar wind in CME-driven shocks and will improve our ability to model the interplay of shock evolution and particle acceleration.

Keywords: solar energetic particles; solar coronal mass ejection shocks; solar wind
TOI-4010: A System of Three Large Short-period Planets with a Massive Long-period Companion

We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by the Transiting Exoplanet Survey Satellite in Sectors 24, 25, 52, and 58. We confirm these planets with the High Accuracy Radial velocity Planet Searcher for the Northern Hemisphere radial velocity observations and measure their masses with 8-12% precision. TOI-4010 b is a sub-Neptune (P = 1.3 days, ${R}_{p}={3.02}_{-0.08}^{+0.08}\,{R}_{\oplus }$ , ${M}_{p}={11.00}_{-1.27}^{+1.29}\,{M}_{\oplus }$ ) in the hot-Neptune desert, and is one of the few such planets with known companions. Meanwhile, TOI-4010 c (P = 5.4 days, ${R}_{p}={5.93}_{-0.12}^{+0.11}\,{R}_{\oplus }$ , ${M}_{p}={20.31}_{-2.11}^{+2.13}\,{M}_{\oplus }$ ) and TOI-4010 d (P = 14.7 days, ${R}_{p}={6.18}_{-0.14}^{+0.15}\,{R}_{\oplus }$ , ${M}_{p}={38.15}_{-3.22}^{+3.27}\,{M}_{\oplus }$ ) are similarly sized sub-Saturns on short-period orbits. Radial velocity observations also reveal a super-Jupiter-mass companion called TOI-4010 e in a long-period, eccentric orbit (P ~ 762 days and e ~ 0.26 based on available observations). TOI-4010 is one of the few systems with multiple short-period sub-Saturns to be discovered so far.

Keywords: exoplanets; hot neptunes; exoplanet systems; transit photometry; exoplanet dynamics
Can Warm Absorbers Be Driven by Ultra-fast Outflows?

Warm absorbers (WAs) located approximately in the region of 1-1000 pc are common phenomena in many active galactic nuclei (AGNs). The driving mechanism of WAs is still under debate. Ultra-fast outflows (UFOs) that are launched very close to the central black hole are also frequently observed in AGNs. When UFOs move outward, they collide with the interstellar medium (ISM) gas. In this paper, we study the possibility that WAs can be generated by the interaction between ISM gas and the UFOs. We find that under some ISM gas conditions, WAs can be generated. However, the covering factor of WAs is much smaller than that given by observations. This indicates that other mechanisms should also be at work. We also find that the properties of the WAs mainly depend on the density of the ISM injected into the computational domain from the outer radial boundary (1000 pc). The higher the density of the ISM is, the higher the mass flux and kinetic power of the WAs will be. The kinetic power of the UFO-driven WAs is much less than 1% of the bolometric luminosity of the host AGNs. Therefore, the UFO-driven WAs might not contribute sufficient feedback to the host galaxy.

Keywords: black hole physics; active galaxies; galaxy nuclei; accretion; active galactic nuclei
Optimization of Future Multifilter Surveys Toward Asteroid Characterization

The aim of this paper is to find a set of photometric passbands that will give optimal results for spectrophotometric classification of asteroids into taxonomic types and classes. For this purpose various machine-learning methods are used, namely multinomial logistic regression, naive Bayes, support vector machines, gradient boosting, and multilayer perceptrons. Sequential feature selection is performed to assess the contribution of each reflectance difference. We find that to determine the taxonomic complexes with a balanced accuracy of 85%, a set of five spectrophotometric bands is required. For taxonomy type determination with the balanced accuracy of 80% a set of eight bands is necessary. Furthermore, only a three-band system is enough for distinguishing the C-complex asteroids with 92% balanced accuracy. These results can be used for designing future asteroid multifilter sky surveys.

Keywords: asteroid surfaces; spectroscopy; multi-color photometry
WIYN Open Cluster Study. LXXXIV. The Effect of Chromospheric Activity on Oxygen Abundances from the 7774 Å Triplet in Pleiades Dwarfs

We present a spectroscopic analysis of 7774 Å O I triplet abundances, 8498-8662 Å Ca II triplet chromospheric activity, and rotation in the Pleiades open cluster, with the objective of thoroughly examining the O triplet overabundance trends observed in cool open cluster dwarfs, and to thereby make clear the cause of that trend. High-dispersion, contemporaneous spectra of the O I triplet, Ca II triplet, and Hα spectral regions in 41 Pleiades dwarfs were acquired using Hydra on the WIYN 3.5 m telescope. Our Ca II emission equivalent-width data exhibit a strong positive correlation with decreasing Teff, with the rapidly rotating stars enhanced by up to 50% above the slowly rotating stars. Our triplet [O/H] values exhibit a statistically significant positive correlation with total Ca II triplet emission, and similarly, significant correlations have been found by every study to date that used contemporaneous O triplet abundance and chromospheric activity data, which is strong evidence that chromospheric activity is the cause of the observed overabundance trends. Based on the slowly rotating, low Ca II emission stars in the near-solar range 5450 K < Teff < 6100 K, we find a cluster mean [O/H] = + 0.143 ± 0.061, consistent with the substantial super-solar [O/H] values exhibited by most young ( < 1 Gyr) open clusters. We also find a cluster mean [Fe/H] = + 0.029 ± 0.034, in excellent agreement with previous studies.

Keywords: open star clusters; stellar abundances; stellar activity
Clouds and Seasonality on Terrestrial Planets with Varying Rotation Rates

Using an idealized climate model incorporating seasonal forcing, we investigate the impact of rotation rate on the abundance of clouds on an Earth-like aquaplanet, and the resulting impacts upon albedo and seasonality. We show that the cloud distribution varies significantly with season, depending strongly on the rotation rate, and is well explained by the large-scale circulation and atmospheric state. Planetary albedo displays nonmonotonic behavior with rotation rate, peaking at around 1/2ΩE. Clouds reduce the surface temperature and total precipitation relative to simulations without clouds at all rotation rates, and reduce the dependence of total precipitation on rotation rate, causing nonmonotonic behavior and a local maximum around 1/8ΩE; these effects are related to the impacts of clouds on the net atmospheric and surface radiative energy budgets. Clouds also affect the seasonality. The influence of clouds on the extent of the winter Hadley cell and the intertropical convergence zone is relatively minor at slow rotation rates (<1/8ΩE), but becomes more pronounced at intermediate rotation rates, where clouds decrease their maximum latitudes. The timing of seasonal transitions varies with rotation rate, and the addition of clouds reduces the seasonal phase lag.

Keywords: atmospheric dynamics; planetary atmospheres; exoplanet atmospheres; planetary climates; albedo; planetary science; seasonal phenomena
Limits on the Hard X-Ray Emission From the Periodic Fast Radio Burst FRB 180916.J0158+65

FRB 180916.J0158+65 is one of the nearest, periodically repeating, and actively bursting fast radio bursts (FRBs) that has been localized to the outskirts of a spiral galaxy. In this work we study the FRB with the hard X-ray 14-195 keV data from the Burst Alert Telescope (BAT) on board The Neil Gehrels Swift Observatory. BAT uses coded mask technology giving a localization of ≲3' in the hard X-ray band, along with an accurate background estimation. BAT has been observing the source location in survey mode since 2020 February. The survey mode observations involve background subtracted spectra, integrated over a time span ranging 300-2000 s at the source location (from 2022 February-2022 January). We analyzed all the ~230 survey mode observations from BAT and checked for any signal in any of the observations. We did not detect any signal at >5σ confidence level in any of the observations. We could estimate a 5σ upper limit on the 14-195 keV flux, which ranged between 4.5 × 10-10-7.6 × 10-9 erg cm-2 s-1. At the source distance this relates to a 5σ upper limit on a luminosity of 5.08 × 1044-8.5 × 1045 erg s-1. With this estimate, we could rule out any persistent X-ray emission at the source location for these snapshots of BAT observations.

Keywords: radio transient sources
Tracking Cosmic-Ray Spectral Variation during 2007-2018 Using Neutron Monitor Time-delay Measurements

The energy spectrum of Galactic cosmic-ray (GCR) ions at Earth varies with solar activity as these ions cross the heliosphere. Thus, this "solar modulation" of GCRs provides remote sensing of heliospheric conditions throughout the ∼11 yr sunspot cycle and ∼22 yr solar magnetic cycle. A neutron monitor (NM) is a stable ground-based detector that measures cosmic-ray rate variations above a geomagnetic or atmospheric cutoff rigidity with high precision (∼0.1%) over such timescales. Furthermore, we developed electronics and analysis techniques to indicate variations in the cosmic-ray spectral index using neutron time-delay data from a single station. Here we study solar modulation using neutron time-delay histograms from two high-altitude NM stations: (1) the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, with the world's highest vertical geomagnetic cutoff rigidity, 16.7 GV, from 2007 December to 2018 April; and (2) the South Pole NM, with an atmosphere-limited cutoff of ∼1 GV, from 2013 December to 2018 April. From these histograms, we extract the leader fraction L, I.e., inverse neutron multiplicity, as a proxy of a GCR spectral index above the cutoff. After correction for pressure and precipitable water vapor variations, we find that L roughly correlates with the count rate but also exhibits hysteresis, implying a change in spectral shape after a solar magnetic polarity reversal. Spectral variations due to Forbush decreases, 27 day variations, and a ground-level enhancement are also indicated. These methods enhance the high-precision GCR spectral information from the worldwide NM network and extend it to higher rigidity.

Keywords: cosmic rays; solar-terrestrial interactions; solar cycle
Artificial Broadcasts as Galactic Populations. I. A Point Process Formalism for Extraterrestrial Intelligences and Their Broadcasts

Artificial broadcasts from extraterrestrial intelligences are a hypothetical class of celestial phenomena. Unlike known astrophysical objects, the societies that generate them may be able to replicate on galactic scales through interstellar travel. Different galaxies could thus have drastically different populations, with variations in abundance of many orders of magnitude. I present a probabilistic formalism to treat this shared history, in which societies and their broadcasts are described by distributions over basic properties like lifespan and energy released. The framework contains a hierarchy of objects related by a tree structure. Discrete societies, the sources of broadcasts, are organized into potentially interstellar metasocieties. The population of each type of object is represented by a random point process in an abstract parameter hyperspace, a haystack. When a selection like an observation draws a sample, the point process is thinned. Given assumptions of interchangeability and independence, observables are modeled with compound Poisson random variables. I present an example of how selection bias can favor sampling longer-lived objects. I rederive the Drake equation for societies in the limit of no expansion. When interstellar replication is present, however, the mean number of detected broadcasts can depend quadratically on stellar mass, suggesting a search strategy favoring large galaxies.

Keywords: search for extraterrestrial intelligence; technosignatures; astronomical techniques; poisson distribution; spatial point processes
Individual Estimates of the Virial Factor in 10 Quasars: Implications on the Kinematics of the Broad-line Region

Assuming a gravitational origin for the Fe IIIλλ2039-2113 redshift and using microlensing based estimates of the size of the region emitting this feature, we obtain individual measurements of the virial factor, f, in 10 quasars. The average values for the Balmer lines, $\langle {f}_{{\rm{H}}\beta }\rangle =0.43\pm 0.20$ and $\langle {f}_{{\rm{H}}\alpha }\rangle =0.50\pm 0.24$ , are in good agreement with the results of previous studies for objects with lines of comparable widths. In the case of Mg II, consistent results, ${f}_{\mathrm{Mg}{\rm{II}}}\sim 0.44$ , can be also obtained accepting a reasonable scaling for the size of the emitting region. The modeling of the cumulative histograms of individual measurements, CDF(f), indicates a relatively high value for the ratio between isotropic and cylindrical motions, $a\sim 0.4\mbox{--}0.7$ . On the contrary, we find very large values of the virial factor associated to the Fe IIIλλ2039-2113 blend, ${f}_{\mathrm{Fe}{\rm{III}}}=14.3\pm 2.4$ , which can be explained if this feature arises from a flattened nearly face-on structure, similar to the accretion disk.

Keywords: active galaxies; quasars; supermassive black holes
Toward Cosmological Simulations of Dark Matter on Quantum Computers

State-of-the-art cosmological simulations on classical computers are limited by time, energy, and memory usage. Quantum computers can perform some calculations exponentially faster than classical computers, using exponentially less energy and memory, and may enable extremely large simulations that accurately capture the whole dynamic range of structure in the universe within statistically representative cosmic volumes. However, not all computational tasks exhibit a "quantum advantage." Quantum circuits act linearly on quantum states, so nonlinearities (e.g., self-gravity in cosmological simulations) pose a significant challenge. Here we outline one potential approach to overcome this challenge and solve the (nonlinear) Schrödinger-Poisson equations for the evolution of self-gravitating dark matter, based on a hybrid quantum-classical variational algorithm framework (Lubasch et al.). We demonstrate the method with a proof-of-concept mock quantum simulation, envisioning a future where quantum computers will one day lead simulations of dark matter.

Keywords: gravitation; computational methods; dark matter
The IXPE View of GRB 221009A

We present the IXPE observation of GRB 221009A, which includes upper limits on the linear polarization degree of both prompt and afterglow emission in the soft X-ray energy band. GRB 221009A is an exceptionally bright gamma-ray burst (GRB) that reached Earth on 2022 October 9 after traveling through the dust of the Milky Way. The Imaging X-ray Polarimetry Explorer (IXPE) pointed at GRB 221009A on October 11 to observe, for the first time, the 2-8 keV X-ray polarization of a GRB afterglow. We set an upper limit to the polarization degree of the afterglow emission of 13.8% at a 99% confidence level. This result provides constraints on the jet opening angle and the viewing angle of the GRB, or alternatively, other properties of the emission region. Additionally, IXPE captured halo-rings of dust-scattered photons that are echoes of the GRB prompt emission. The 99% confidence level upper limit to the prompt polarization degree depends on the background model assumption, and it ranges between ~55% and ~82%. This single IXPE pointing provides both the first assessment of X-ray polarization of a GRB afterglow and the first GRB study with polarization observations of both the prompt and afterglow phases.

Keywords: gamma-ray bursts; polarimetry; x-ray astronomy
Magnetized Outflows from Short-lived Neutron Star Merger Remnants Can Produce a Blue Kilonova

We present a 3D general-relativistic magnetohydrodynamic simulation of a short-lived neutron star remnant formed in the aftermath of a binary neutron star merger. The simulation uses an M1 neutrino transport scheme to track neutrino-matter interactions and is well suited to studying the resulting nucleosynthesis and kilonova emission. A magnetized wind is driven from the remnant and ejects neutron-rich material at a quasi-steady-state rate of 0.8 × 10-1 M ⊙s-1. We find that the ejecta in our simulations underproduce r-process abundances beyond the second r-process peak. For sufficiently long-lived remnants, these outflows alone can produce blue kilonovae, including the blue kilonova component observed for AT2017gfo.

Keywords: transient sources; compact objects; neutron stars
Improved Redshifts for DESI EDR Quasars

The Dark Energy Spectroscopic Instrument (DESI) survey will provide optical spectra for ~3 million quasars. Accurate redshifts for these quasars will facilitate a broad range of science applications. Here we provide improved systemic redshift estimates for the ~95k quasars included in the DESI Early Data Release (EDR), based on emission-line fits to the quasar spectra. The majority of the DESI pipeline redshifts are reliable. However, ~19% of the EDR quasars have pipeline redshifts that deviate from our new redshifts by >500 km s-1. We use composite quasar spectra to demonstrate the improvement of our redshift estimates, particularly at z > 1. These new redshifts are available on Zenodo:10.5281/zenodo.8302310 <!--AQ1--> .

Keywords: surveys; quasars
Linearized Field Deblending: Point-spread Function Photometry for Impatient Astronomers

NASA's Kepler, K2, and TESS missions employ simple aperture photometry to derive time-series photometry, where an aperture is estimated for each star, and pixels containing each star are summed to create a single light curve. This method is simple, but in crowded fields, the derived time series can be highly contaminated. The alternate method of fitting a point-spread function (PSF) to the data is able to account for crowding but is computationally expensive. In this paper, we present a new approach to extracting photometry from these time-series missions that fits the PSF directly but makes simplifying assumptions in order to greatly reduce the computation expense. Our method fixes the scene of the field in each image, estimates the PSF shape of the instrument with a linear model, and allows only source flux and position to vary. We demonstrate that our method is able to separate the photometry from blended targets in the Kepler data set that are separated by less than a pixel. Our method is fast to compute and fully accounts for uncertainties from degeneracies due to crowded fields. We name the method described in this work linearized field deblending photometry. We demonstrate our method on the false-positive Kepler target KOI-608. We are able to separate the photometry of the two sources in the data and demonstrate that the contaminating transiting signal is consistent with a small, substellar companion with a radius of 2.67 RJup (0.27 R⊙). Our method is equally applicable to extracting photometry from NASA's TESS mission.

Keywords: time series analysis; photometry; computational methods; astronomy data analysis
Phase Mixing and the 1/f Spectrum in the Solar Wind

The origin and evolution of the 1/f power law observed in the energy spectrum of solar coronal and solar wind fluctuations at scales of around an hour is not entirely understood. Several existing theories aim at explaining it, involving both linear and nonlinear mechanisms. An often overlooked property of the solar corona and solar wind is their highly inhomogeneous nature. In this paper we investigate the linear evolution of pure Alfvén and surface Alfvén waves propagating through a plasma that is inhomogeneous across the magnetic field. The inhomogeneity is given by density, which we model to be 2D colored noise, with power spectral slopes ranging from -2 to -1. Alfvén waves propagate independently on individual magnetic field lines, and eventually get completely out of phase through the process of phase mixing, leading to unrealistic spectra. When the coupling between the inhomogeneous background and the propagating waves is fully accounted for, transverse waves such as surface Alfvén waves (also referred to as kink or Alfvénic) appear, showing collective wave behavior of neighboring magnetic field lines with different Alfvén speeds. We show that the linear cascade of surface Alfvén wave energy, induced by phase mixing and resonant absorption, leads to a perpendicular wave energy spectrum, which tends to the perpendicular power spectrum of the background density. Based on our model, we propose that a perpendicular density power spectrum of 1/f in the solar corona can induce, through linear processes, the 1/f spectrum of the fluctuations that is observed at the largest scales.

Keywords: solar wind; solar physics; magnetohydrodynamics; plasma astrophysics
Nine New Repeating Fast Radio Burst Sources from CHIME/FRB

We report on the discovery and analysis of bursts from nine new repeating fast radio burst (FRB) sources found using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These sources span a dispersion measure (DM) range of 195-1380 pc cm-3. We detect two bursts from three of the new sources, three bursts from four of the new sources, four bursts from one new source, and five bursts from one new source. We determine sky coordinates of all sources with uncertainties of ∼10'. We detect Faraday rotation measures (RMs) for two sources, with values -20(1) and -499.8(7) rad m-2, that are substantially lower than the RM derived from bursts emitted by FRB 121102. We find that the DM distribution of our events, combined with the nine other repeaters discovered by CHIME/FRB, is indistinguishable from that of thus far non-repeating CHIME/FRB events. However, as previously reported, the burst widths appear statistically significantly larger than the thus far non-repeating CHIME/FRB events, further supporting the notion of inherently different emission mechanisms and/or local environments. These results are consistent with previous work, though are now derived from 18 repeating sources discovered by CHIME/FRB during its first year of operation. We identify candidate galaxies that may contain FRB 190303.J1353+48 (DM = 222.4 pc cm-3).

Keywords: radio transient sources