adsabs/SciX_UAT_keywords huggingface dataset:
Rotating Solar Models in Agreement with Helioseismic Results and Updated Neutrino Fluxes

Standard solar models (SSMs) constructed in accordance with old solar abundances are in reasonable agreement with seismically inferred results, but SSMs with new low-metal abundances disagree with the seismically inferred results. The constraints of neutrino fluxes on solar models exist in parallel with those of helioseismic results. The solar neutrino fluxes were updated by the Borexino Collaboration. We constructed rotating solar models with new low-metal abundances where the effects of enhanced diffusion and convection overshoot were included. A rotating model using OPAL opacities and the Caffau abundance scale has better sound-speed and density profiles than the SSM with the old solar abundances and reproduces the observed p-mode frequency ratios r 02 and r 13. The depth and helium abundance of the convection zone of the model agree with the seismically inferred ones at the level of 1σ. The updated neutrino fluxes are also reproduced by the model at the level of 1σ. The effects of rotation and enhanced diffusion not only improve the model's sound-speed and density profiles but also bring the neutrino fluxes predicted by the model into agreement with the detected ones. Moreover, the calculations show that OP may underestimate opacities for the regions of the Sun with T ≳ 5 × 106 K by around 1.5%, while OPAL may underestimate opacities for the regions of the Sun with 2 × 106 K ≲ T ≲ 5 × 106 K by about 1%-2%.

Keywords: solar abundances; helioseismology; solar rotation; solar interior; solar neutrinos
Single-pulse Variability in Gamma-Ray Pulsars

The Fermi Large Area Telescope receives ≪1 photon per rotation from any γ-ray pulsar. However, out of the billions of monitored rotations of the bright pulsars Vela (PSR J0835-4510) and Geminga (PSR J0633+1746), a few thousand have ≥2 pulsed photons. These rare pairs encode information about the variability of pulse amplitude and shape. We have cataloged such pairs and find the observed number to be in good agreement with simple Poisson statistics, limiting any amplitude variations to <19% (Vela) and <22% (Geminga) at 2σ confidence. Using an array of basis functions to model pulse-shape variability, the observed pulse phase distribution of the pairs limits the scale of pulse-shape variations of Vela to <13%, while for Geminga we find a hint of ~20% single-pulse-shape variability most associated with the pulse peaks. If variations last longer than a single rotation, more pairs can be collected, and we have calculated upper limits on amplitude and shape variations for assumed coherence times up to 100 rotations, finding limits of ~1% (amplitude) and ~3% (shape) for both pulsars. Because a large volume of the pulsar magnetosphere contributes to γ-ray pulse production, we conclude that the magnetospheres of these two energetic pulsars are stable over one rotation and very stable on longer timescales. All other γ-ray pulsars are too faint for similar analyses. These results provide useful constraints on rapidly improving simulations of pulsar magnetospheres, which have revealed a variety of large-scale instabilities in the thin equatorial current sheets where the bulk of GeV γ-ray emission is thought to originate.

Keywords: pulsars; pulsar timing method; gamma-ray astronomy; gamma-ray sources
Search for Multi-flare Neutrino Emissions in 10 yr of IceCube Data from a Catalog of Sources

A recent time-integrated analysis of a catalog of 110 candidate neutrino sources revealed a cumulative neutrino excess in the data collected by IceCube between 2008 April 6 and 2018 July 10. This excess, inconsistent with the background hypothesis in the Northern Hemisphere at the 3.3σ level, is associated with four sources: NGC 1068, TXS 0506+056, PKS 1424+240, and GB6 J1542+6129. This Letter presents two time-dependent neutrino emission searches on the same data sample and catalog: a point-source search that looks for the most significant time-dependent source of the catalog by combining space, energy, and time information of the events, and a population test based on binomial statistics that looks for a cumulative time-dependent neutrino excess from a subset of sources. Compared to previous time-dependent searches, these analyses enable a feature to possibly find multiple flares from a single direction with an unbinned maximum-likelihood method. M87 is found to be the most significant time-dependent source of this catalog at the level of 1.7σ post-trial, and TXS 0506+056 is the only source for which two flares are reconstructed. The binomial test reports a cumulative time-dependent neutrino excess in the Northern Hemisphere at the level of 3.0σ associated with four sources: M87, TXS 0506+056, GB6 J1542+6129, and NGC 1068.

Keywords: neutrino astronomy; high energy astrophysics; particle astrophysics
Seven Years of Coordinated Chandra-NuSTAR Observations of SN 2014C Unfold the Extreme Mass-loss History of Its Stellar Progenitor

We present the results from our 7 yr long broadband X-ray observing campaign of SN 2014C with Chandra and NuSTAR. These coordinated observations represent the first look at the evolution of a young extragalactic SN in the 0.3-80 keV energy range in the years after core collapse. We find that the spectroscopic metamorphosis of SN 2014C from an ordinary type Ib SN into an interacting SN with copious hydrogen emission is accompanied by luminous X-rays reaching L x ≈ 5.6 × 1040 erg s-1 (0.3-100 keV) at ~1000 days post-explosion and declining as L x ∝ t -1 afterwards. The broadband X-ray spectrum is of thermal origin and shows clear evidence for cooling after peak, with $T{(t)\approx 20\,\mathrm{keV}(t/{t}_{\mathrm{pk}})}^{-0.5}$ . Soft X-rays of sub-keV energy suffer from large photoelectric absorption originating from the local SN environment with ${\mathrm{NH}}_{\mathrm{int}}{(t)\approx 3\times {10}^{22}(t/400\,\mathrm{days})}^{-1.4}\,{\mathrm{cm}}^{-2}$ . We interpret these findings as the result of the interaction of the SN shock with a dense (n ≈ 105 - 106 cm-3), H-rich disk-like circumstellar medium (CSM) with inner radius ~2 × 1016 cm and extending to ~1017 cm. Based on the declining NHint(t) and X-ray luminosity evolution, we infer a CSM mass of ~(1.2 f-2.0 $\sqrt{f}){M}_{\odot }$ , where f is the volume filling factor. We place SN 2014C in the context of 121 core-collapse SNe with evidence for strong shock interaction with a thick circumstellar medium. Finally, we highlight the challenges that the current mass-loss theories (including wave-driven mass loss, binary interaction, and line-driven winds) face when interpreting the wide dynamic ranges of CSM parameters inferred from observations.

Keywords: core-collapse supernovae; x-ray astronomy; shocks; circumstellar shells
Generation of Solar-like Differential Rotation

We analyze the simulation result shown in Hotta & Kusano (2021) in which the solar-like differential rotation is reproduced. The Sun is rotating differentially with the fast equator and the slow pole. It is widely thought that the thermal convection maintains the differential rotation, but recent high-resolution simulations tend to fail to reproduce the fast equator. This fact is an aspect of one of the biggest problems in solar physics called the convective conundrum. Hotta & Kusano succeed in reproducing the solar-like differential rotation without using any manipulation with an unprecedentedly high-resolution simulation. In this study, we analyze the simulation data to understand the maintenance mechanism of the fast equator. Our analyses lead to conclusions that are summarized as follows. (1) The superequipatition magnetic field is generated by the compression, which can indirectly convert the massive internal energy to magnetic energy. (2) The efficient small-scale energy transport suppresses large-scale convection energy. (3) Non-Taylor-Proudman differential rotation is maintained by the entropy gradient caused by the anisotropic latitudinal energy transport enhanced by the magnetic field. (4) The fast equator is maintained by the meridional flow mainly caused by the Maxwell stress. The Maxwell stress itself also has a role in the angular momentum transport for the fast near-surface equator (we call it the P unching ball effect). The fast equator in the simulation is reproduced not due to the low Rossby number regime but due to the strong magnetic field. This study newly finds the role of the magnetic field in the maintenance of differential rotation.

Keywords: stellar convective zones; solar convective zone
Pressure-Strain Interaction as the Energy Dissipation Estimate in Collisionless Plasma

The dissipative mechanism in weakly collisional plasma is a topic that pervades decades of studies without a consensus solution. We compare several energy dissipation estimates based on energy transfer processes in plasma turbulence and provide justification for the pressure-strain interaction as a direct estimate of the energy dissipation rate. The global and scale-by-scale energy balances are examined in 2.5D and 3D kinetic simulations. We show that the global internal energy increase and the temperature enhancement of each species are directly tracked by the pressure-strain interaction. The incompressive part of the pressure-strain interaction dominates over its compressive part in all simulations considered. The scale-by-scale energy balance is quantified by scale filtered Vlasov-Maxwell equations, a kinetic plasma approach, and the lag dependent von Kármán-Howarth equation, an approach based on fluid models. We find that the energy balance is exactly satisfied across all scales, but the lack of a well-defined inertial range influences the distribution of the energy budget among different terms in the inertial range. Therefore, the widespread use of the Yaglom relation in estimating the dissipation rate is questionable in some cases, especially when the scale separation in the system is not clearly defined. In contrast, the pressure-strain interaction balances exactly the dissipation rate at kinetic scales regardless of the scale separation.

Keywords: interplanetary turbulence; plasma astrophysics; solar wind; plasma physics
A Photoionization Mass Spectrometry Investigation into Complex Organic Molecules Formed in Interstellar Analog Ices of Carbon Monoxide and Water Exposed to Ionizing Radiation

The formation of complex organic molecules by energetic electrons mimicking secondary electrons generated within trajectories of galactic cosmic rays was investigated in interstellar ice analog samples of carbon monoxide and water at 5 K. Simulating the transition from cold molecular clouds to star-forming regions, newly formed products sublimed during the temperature-programmed desorption and were detected utilizing isomer-specific photoionization reflectron time-of-flight mass spectrometry. Using isotopically labeled ices, tunable photoionization, and adiabatic ionization energies to discriminate between isomers, isomers up to ${{\rm{C}}}_{2}{{\rm{H}}}_{4}{{\rm{O}}}_{2}$ and ${{\rm{C}}}_{2}{{\rm{H}}}_{6}{{\rm{O}}}_{2}$ were identified, while non-isomer-specific findings confirmed complex organics with molecular formulas up to ${{\rm{C}}}_{4}{{\rm{H}}}_{6}{{\rm{O}}}_{4}$. The results provide important constraints on reaction pathways from simple inorganic precursors to complex organic molecules that have both astrochemical and astrobiological significance.

Keywords: laboratory astrophysics; interdisciplinary astronomy; interstellar molecules; astrochemistry
Exploring the Nature of EUV Waves in a Radiative Magnetohydrodynamic Simulation

Coronal extreme-ultraviolet (EUV) waves are large-scale disturbances propagating in the corona, whose physical nature and origin have been discussed for decades. We report the first three-dimensional (3D) radiative magnetohydrodynamic simulation of a coronal EUV wave and the accompanying quasi-periodic wave trains. The numerical experiment is conducted with the MURaM code and simulates the formation of solar active regions through magnetic flux emergence from the convection zone to the corona. The coronal EUV wave is driven by the eruption of a magnetic flux rope that also gives rise to a C-class flare. It propagates in a semicircular shape with an initial speed ranging from about 550 to 700 km s-1, which corresponds to an average Mach number (relative to fast magnetoacoustic waves) of about 1.2. Furthermore, the abrupt increase of the plasma density, pressure, and tangential magnetic field at the wave front confirms fast-mode shock nature of the coronal EUV wave. Quasi-periodic wave trains with a period of about 30 s are found as multiple secondary wavefronts propagating behind the leading wave front and ahead of the erupting magnetic flux rope. We also note that the true wave front in the 3D space can be very inhomogeneous; however, the line-of-sight integration of EUV emission significantly smoothes the sharp structures in 3D and leads to a more diffuse wave front.

Keywords: radiative magnetohydrodynamics; solar extreme ultraviolet emission; solar corona; solar coronal waves; solar activity
Jupiter's Early Luminosity May Have Driven off Io's Initial Water Inventory

After its formation, Jupiter was substantially more luminous than it is at the present day (104 times). Right after formation, the inner satellites Io and Europa would have received an order-of-magnitude larger incoming flux from Jupiter, than solar insolation. However, little work has been done to examine the impact this would have had on the Galilean satellites. In this work we explore the possibility that Jupiter's early luminosity could have caused the loss of any initial water inventory on Io and Europa. We find that, depending on Jupiter's luminosity after the proto-Jovian disk dissipates, heating from Jupiter could drive rapid water loss via hydrodynamic escape. If early tidal heating dehydrated Io's accreted silicates, this may provide a mechanism to lose Io's initial water inventory.

Keywords: natural satellite formation; jupiter; europa; jovian satellites; io; atmospheric dynamics
A New Method for the Reconstruction of Strongly Lensed Galaxies with Resolved Kinematics

Integral field spectroscopy of high-redshift galaxies has become a powerful tool for understanding their dynamics and evolutionary states. However, in the case of gravitationally lensed systems, it has proved difficult to model both lensing and intrinsic kinematics in a way that takes full advantage of the information available in the spectral domain. In this paper, we introduce a new method for pixel-based source reconstruction that alters standard regularization schemes for two-dimensional (2D) data in a way that leverages kinematic information in a physically motivated but flexible fashion, and that is better suited to the three-dimensional (3D) nature of integral field data. To evaluate the performance of this method, we compare its results to those of a more traditional 2D nonparametric approach using mock Atacama Large Millimeter/submillimeter Array (ALMA) observations of a typical high-redshift dusty star-forming galaxy. We find that 3D regularization applied to an entire data cube reconstructs a source's intensity and velocity structure more accurately than 2D regularization applied to separate velocity channels. Cubes reconstructed with 3D regularization also have more uniform noise and resolution properties and are less sensitive to the signal-to-noise ratio of individual velocity channels than the results of 2D regularization. Our new approach to modeling integral field observations of lensed systems can be implemented without making restrictive a priori assumptions about intrinsic kinematics, and opens the door to new observing strategies that prioritize spectral resolution over spatial resolution (e.g., for multiconfiguration arrays like ALMA).

Keywords: gravitational lensing; galaxy kinematics; galaxy dynamics; high-redshift galaxies; galaxy evolution; galaxies
The Three Young Nuclear Super Star Clusters in NGC 5253

The blue compact dwarf galaxy NGC 5253 hosts a very young central starburst. The center contains intense radio thermal emission from a massive ultracompact H II region (or supernebula) and two massive and very young super star clusters (SSCs), which are seen at optical and infrared wavelengths. The spatial correspondence between these three objects over an area of $\lt 0\buildrel{\prime\prime}\over{.} 5$ is very uncertain, and it is usually assumed that one of the optically detected SSCs coincides with the supernebula. Using the Gaia Data Release 2 catalog, we improve the absolute astrometry of Hubble Space Telescope ultraviolet, optical, and infrared images by a factor of ∼10 and match them to the radio observations with an accuracy of 10-20 mas. We find that there are three SSCs at the center of NGC 5253. At optical wavelengths, the two SSCs lie on either side of the supernebula, which coincides with a highly obscured region. In the infrared, all three SSCs are seen with the supernebula dominating at the longest wavelengths. We examine the properties of the SSCs, which have ages of ∼1 Myr, are very compact ( $\lt 0.6$ pc), and are separated by projected distances of only 1.5 and 5.8 pc. It seems likely that they will merge and may form the building blocks for nuclear star clusters.

Keywords: blue compact dwarf galaxies; young star clusters; starburst galaxies
Constraints on the Physical Properties of SNe Ia from Photometry

We present a photometric study of 17 SNe Ia based on multi-color (Johnson-Cousins-Bessell BVRI) data taken at Piszkéstet&odblac mountain station of Konkoly Observatory, Hungary between 2016 and 2018. We analyze the light curves (LCs) using the publicly available LC-fitter SNooPy2 to derive distance and reddening information. The bolometric LCs are fit with a radiation-diffusion Arnett model to get constraints on the physical parameters of the ejecta: the optical opacity, the ejected mass and the initial nickel mass in particular. We also study the pre-maximum, dereddened (B-V)0 color evolution by comparing our data with standard delayed detonation and pulsational delayed detonation models, and show that the 56Ni masses of the models that fit the (B-V)0 colors are consistent with those derived from the bolometric LC fitting. We find similar correlations between the ejecta parameters (e.g., ejecta mass, or 56Ni mass versus decline rate) as published recently by Scalzo et al. (2019).

Keywords: type ia supernovae; ejecta; johnson photometry
Jet Lorentz Factor Constraint for GRB 221009A Based on the Optical Depth of the TeV Photons

The recent detection of teraelectronvolt (TeV) photons from the record-breaking gamma-ray burst GRB 221009A during its prompt phase poses challenges for constraining its Lorentz factor. We reevaluate the constraints on the jet Lorentz factor considering a two-zone model, wherein the TeV photons originate from the external shock region while the lower-energy MeV photons come from the internal prompt emission region. By properly accounting for the evolution of the MeV photon spectrum and light curve, we calculate the optical depth for TeV photons and derive a minimum Lorentz factor of about 300. It is consistent with the afterglow modeling for the TeV emission.

Keywords: gamma-ray bursts; high energy astrophysics; relativistic jets; ultra-high-energy cosmic radiation
Dependencies of Kappa Parameter on the Core Energy of Kappa Distributions and Plasma Parameter in the Case of the Magnetosphere of the Earth

Formation of kappa distribution functions and their relaxation to Maxwellian distributions are the main feature of astrophysical and space collisionless plasmas. In this work, we use the magnetosphere of the Earth as a giant plasma laboratory to study the properties of ion kappa distribution functions. Four years of measurements, performed by the multi-satellite Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission during quiet geomagnetic conditions, at geocentric distances from three Earth radii (RE) to the magnetopause at daytime (of the order of 10RE), and up to 20RE at night time are used for the analyses. We find a dependence of the k parameter on the core energy E0 of a single kappa distribution inside the magnetospheric ring current and in the plasma sheet, for different values of the plasma parameter (the ratio between the plasma and magnetic pressures). We show that k increases with E0 for all values of plasma parameter, which supports earlier results obtained for the magnetospheres of the Earth, Jupiter, and Saturn, but using lower statistics. However, contrary to previous results, our studies show that the relation between k and E0 is nonlinear, and most probably is a power law with a nearly constant index. The results obtained are relevant to solve the problem of thermalization of kappa distributions.

Keywords: space plasmas; planetary magnetospheres
The Role of Mass and Environment on Satellite Distributions around Milky Way Analogs in the ROMULUS25 Simulation

We study satellite counts and quenched fractions for satellites of Milky Way analogs in ROMULUS25, a large-volume cosmological hydrodynamic simulation. Depending on the definition of a Milky Way analog, we have between 66 and 97 Milky Way analogs in ROMULUS25, a 25 Mpc per-side uniform volume simulation. We use these analogs to quantify the effect of environment and host properties on satellite populations. We find that the number of satellites hosted by a Milky Way analog increases predominantly with host stellar mass, while environment, as measured by the distance to a Milky Way-mass or larger halo, may have a notable impact in high isolation. Similarly, we find that the satellite quenched fraction for our analogs also increases with host stellar mass, and potentially in higher-density environments. These results are robust for analogs within 3 Mpc of another Milky Way-mass or larger halo, the environmental parameter space where the bulk of our sample resides. We place these results in the context of observations through comparisons to the Exploration of Local VolumE Satellites and Satellites Around Galactic Analogs surveys. Our results are robust to changes in Milky Way analog selection criteria, including those that mimic observations. Finally, as our samples naturally include Milky Way-Andromeda pairs, we examine quenched fractions in pairs versus isolated systems. We find potential evidence, though not conclusive, that pairs, defined as being within 1 Mpc of another Milky Way-mass or larger halo, may have higher satellite quenched fractions.

Keywords: galaxy evolution; galaxy quenching; dwarf galaxies