bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal Pollution of the Solar White Dwarf by Solar System Small Bodies
Authors: Li Daohai , Mustill Alexander J. , Davies Melvyn B.
Published: January 2022

White dwarfs (WDs) often show metal lines in their spectra, indicating accretion of asteroidal material. Our Sun is to become a WD in several gigayears. Here, we examine how the solar WD accretes from the three major small body populations: the main belt asteroids (MBAs), Jovian Trojan asteroids (JTAs), and trans-Neptunian objects (TNOs). Owing to the solar mass loss during the giant branch, 40% of the JTAs are lost but the vast majority of MBAs and TNOs survive. During the WD phase, objects from all three populations are sporadically scattered onto the WD, implying ongoing accretion. For young cooling ages ≲100 Myr, accretion of MBAs predominates; our predicted accretion rate ∼106 g s−1 falls short of observations by two orders of magnitude. On gigayear timescales, thanks to the consumption of the TNOs that kicks in ≳100 Myr, the rate oscillates around 106–107 g s−1 until several gigayears and drops to ∼105 g s−1 at 10 Gyr. Our solar WD accretion rate from 1 Gyr and beyond agrees well with those of the extrasolar WDs. We show that for the solar WD, the accretion source region evolves in an inside-out pattern. Moreover, in a realistic small body population with individual sizes covering a wide range as WD pollutants, the accretion is dictated by the largest objects. As a consequence, the accretion rate is lower by an order of magnitude than that from a population of bodies of a uniform size and the same total mass and shows greater scatter.
Observational Constraints on the Maximum Energies of Accelerated Particles in Supernova Remnants: Low Maximum Energies and a Large Variety
Authors: Suzuki Hiromasa , Bamba Aya , Yamazaki Ryo , Ohira Yutaka
Published: January 2022

Supernova remnants (SNRs) are thought to be the most promising sources of Galactic cosmic rays. One of the principal questions is whether they are accelerating particles up to the maximum energy of Galactic cosmic rays (∼PeV). In this work, a systematic study of gamma-ray-emitting SNRs is conducted as an advanced study of Suzuki et al. Our purpose is to newly measure the evolution of maximum particle energies with increased statistics and better age estimates. We model their gamma-ray spectra to constrain the particle-acceleration parameters. Two candidates of the maximum energy of freshly accelerated particles, the gamma-ray cutoff and break energies, are found to be well below PeV. We also test a spectral model that includes both the freshly accelerated and escaping particles to estimate the maximum energies more reliably, but no tighter constraints are obtained with current statistics. The average time dependences of the cutoff energy (∝t
−0.81±0.24) and break energy (∝t
−0.77±0.23) cannot be explained with the simplest acceleration condition (Bohm limit) and require shock–ISM (interstellar medium) interaction. The average maximum energy during lifetime is found to be ≲20 TeV

(

t

M

/

1

kyr
)

−
0.8

with t

M
being the age at the maximum, which reaches PeV if t

M
≲ 10 yr. The maximum energies during lifetime are suggested to have a variety of 1.1–1.8 dex from object to object. Although we cannot isolate the cause of this variety, this work provides an important clue to understanding the microphysics of particle acceleration in SNRs.
A New Method for Estimating Starspot Lifetimes Based on Autocorrelation Functions
Authors: Basri Gibor , Streichenberger Tristan , McWard Connor , Edmond IV Lawrence , Tan Joanne , Lee Minjoo , Melton Trey
Published: January 2022

We present a method that utilizes autocorrelation functions from long-term precision broadband differential light curves to estimate the average lifetimes of starspot groups for two large samples of Kepler stars: stars with and without previously known rotation periods. Our method is calibrated by comparing the strengths of the first few normalized autocorrelation peaks using ensembles of models that have various starspot lifetimes. We find that we must mix models of short and long lifetimes together (in heuristically determined ratios) to align the models with the Kepler data. Our fundamental result is that short starspot-group lifetimes (one to four rotations) are implied when the first normalized peak is weaker than about 0.4, long lifetimes (15 or greater) are implied when it is greater than about 0.7, and in between are the intermediate cases. Rotational lifetimes can be converted to physical lifetimes if the rotation period is known. Stars with shorter rotation periods tend to have longer rotational (but not physical) spot lifetimes, and cooler stars tend to have longer physical spot lifetimes than warmer stars with the same rotation period. The distributions of the physical lifetimes are log-normal for both samples and generally longer in the first sample. The shorter lifetimes in the stars without known periods probably explain why their periods are difficult to measure. Some stars exhibit longer than average physical starspot lifetimes; their percentage drops with increasing temperature from nearly half at 3000 K to nearly zero for hotter than 6000 K.
A Novel Bimodal Forecasting Model for Solar Cycle 25
Authors: Lu J. Y. , Xiong Y. T. , Zhao K. , Wang M. , Li J. Y. , Peng G. S. , Sun M.
Published: January 2022

In this paper, a novel bimodal model to predict a complete sunspot cycle based on comprehensive precursor information is proposed. We compare the traditional 13 month moving average with the Gaussian filter and find that the latter has less missing information and can better describe the overall trend of the raw data. Unlike the previous models that usually only use one precursor, here we combine the implicit and geometric information of the solar cycle (peak and skewness of the previous cycle and start value of the predicted cycle) with the traditional precursor method based on the geomagnetic index and adopt a multivariate linear approach with a higher goodness of fit (>0.85) in the fitting. Verifications for cycles 22–24 demonstrate that the model has good performance in predicting the peak and peak occurrence time. It also successfully predicts the complete bimodal structure for cycle 22 and cycle 24, showing a certain ability to predict whether the next solar cycle is unimodal or bimodal. It shows that cycle 25 is a single-peak structure and that the peak will come in 2024 October with a peak of 145.3.
Circumnuclear Dust in AP Librae and the Source of Its VHE Emission
Authors: Roychowdhury Agniva , Meyer Eileen T. , Georganopoulos Markos , Breiding Peter , Petropoulou Maria
Published: January 2022

The broad high-energy spectral component in blazars is usually attributed to various inverse Compton scattering processes in the relativistic jet, but has not been clearly identified in most cases due to degeneracies in physical models. AP Librae, a low-synchrotron-peaking BL Lac object (LBL) detected in 2015 by H.E.S.S. at very high energies (VHE; >0.5 TeV), has an extremely broad high-energy spectrum, covering ∼9 decades in energy. Standard synchrotron self-Compton models generally fail to reproduce the VHE emission, which has led to the suggestion that it might arise not from the blazar core, but on kiloparsec scales from inverse Compton (IC) scattering of cosmic microwave background (CMB) photons by a still-relativistic jet (IC/CMB). IC/CMB models for the TeV emission of AP Librae in prior works have implied a high level of infrared emission from the kiloparsec-scale jet. With newly obtained Hubble Space Telescope (HST) imaging, we obtain a deep upper limit on the kiloparsec-scale jet emission at 1.6 μm, well below the expected level. High-resolution Atacama Large Millimeter/submillimeter Array imaging in bands 3–9 reveals a residual dust-disk signature after core subtraction, with a clearly thermal spectrum, and an extent (∼500 pc) that matches with a nonjet residual emission seen after point-spread function subtraction in our 1.6 μm HST imaging. We find that the unusually broad GeV and VHE emission in AP Librae can be reproduced through the combined IC scattering of photons from the CMB and the dust disk, respectively, by electrons in both the blazar core and subkiloparsec jet.
The Warm Gas in the Milky Way: The Kinematical Model of C iv and Its Connection to Si iv
Authors: Qu Zhijie , Lindley Ryan , Bregman Joel N.
Published: January 2022

We compose a 265-sight-line Milky Way C iv line-shape sample using the Hubble Space Telescope/Cosmic Origins Spectrograph archive, which is complementary to the existing Si iv samples. C iv has a higher ionization potential (47–64 eV) than Si iv (33–45 eV), so it also traces warm gas, which is roughly cospatial with Si iv. The spatial density distribution and kinematics of C iv are identical to those Si iv within ≈2σ. C iv is more sensitive to the warm gas density distribution at large radii with a higher element abundance. Applying the kinematical model to the C iv sample, we find two possible solutions of the density distribution, which are distinguished by the relative extension along the disk midplane and the normal-line direction. Both solutions can reproduce the existing sample and suggest a warm gas disk mass of

log
M
(

M

⊙

)
≈
8

and an upper limit of

log
M
(

M

⊙

)
<
9.3

within 250 kpc, which is consistent with Si iv. There is a decrease in the C iv/Si iv column density ratio from the Galactic center to the outskirts by 0.2–0.3 dex, which may suggest a phase transition or different ionization mechanisms for C iv and Si iv. Also, we find that the difference between C iv and Si iv is an excellent tracer of small-scale features, and we find a typical size of 5°–10° for possible turbulence within individual clouds (≈1 kpc).
Data-driven Expectations for Electromagnetic Counterpart Searches Based on LIGO/Virgo Public Alerts
Authors: Petrov Polina , Singer Leo P. , Coughlin Michael W. , Kumar Vishwesh , Almualla Mouza , Anand Shreya , Bulla Mattia , Dietrich Tim , Foucart Francois , Guessoum Nidhal
Published: January 2022

Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been a second, secure identification of an electromagnetic counterpart. This is not surprising given that the localization uncertainties of events in LIGO and Virgo’s third observing run, O3, were much larger than predicted. We explain this by showing that improvements in data analysis that now allow LIGO/Virgo to detect weaker and hence more poorly localized events have increased the overall number of detections, of which well-localized, gold-plated events make up a smaller proportion overall. We present simulations of the next two LIGO/Virgo/KAGRA observing runs, O4 and O5, that are grounded in the statistics of O3 public alerts. To illustrate the significant impact that the updated predictions can have, we study the follow-up strategy for the Zwicky Transient Facility. Realistic and timely forecasting of gravitational-wave localization accuracy is paramount given the large commitments of telescope time and the need to prioritize which events are followed up. We include a data release of our simulated localizations as a public proposal planning resource for astronomers.
Gamma-Ray Orbital Modulation of the Transitioning Millisecond Pulsar Binary XSS J12270–4859
Authors: An Hongjun
Published: January 2022

We report on gamma-ray orbital modulation of the transitioning MSP binary XSS J12270–4859 detected in the Fermi Large Area Telescope (LAT) data. We use long-term optical data taken with the XMM-Newton OM and the Swift UltraViolet Optical Telescope to inspect radio timing solutions that are limited to relatively short time intervals and find that extrapolation of the solutions aligns well with the phasing of the optical data over 15 yr. The Fermi-LAT data folded on the timing solutions exhibit significant modulation (p = 5 × 10−6) with a gamma-ray minimum at the inferior conjunction of the pulsar. Intriguingly, the source seems to show similar modulation in both the low-mass X-ray binary and the MSP states, implying that mechanisms for gamma-ray emission in the two states are similar. We discuss these findings and their implications using an intrabinary shock scenario.
Two Correlations with Enhancement Near the Proton Gyroradius Scale in Solar Wind Turbulence: Parker Solar Probe (PSP) and Wind Observations
Authors: Zhao G. Q. , Lin Y. , Wang X. Y. , Feng H. Q. , Wu D. J. , Kasper J. C.
Published: January 2022

Based on the Parker Solar Probe mission, this paper presents the observations of two correlations in solar wind turbulence near the Sun for the first time, demonstrating the clear existence of the following two correlations. One is positive correlation between the proton temperature and turbulent magnetic energy density. The other is negative correlation between the spectral index and magnetic helicity. It is found that the former correlation has a maximum correlation coefficient (CC) at the wavenumber k
ρ

p
≃ 0.5 (ρ

p
being the proton thermal gyroradius), and the latter correlation has a maximum absolute value of CC at k
ρ

p
≃ 1.8. In addition, investigations based on 11 yr of Wind observations reveal that the dimensionless wavenumbers (k
ρ

p
) corresponding to the maximum (absolute) values of CC remain nearly the same for different data sets. These results tend to suggest that the two correlations enhanced near the proton gyroradius scale would be a common feature of solar wind turbulence.
Three-dimensional Hybrid Simulation Results of a Variable Magnetic Helicity Signature at Proton Kinetic Scales
Authors: Vasquez Bernard J. , Markovskii Sergei A. , Smith Charles W.
Published: January 2022

Three-dimensional hybrid kinetic simulations are conducted with particle protons and warm fluid electrons. Alfvénic fluctuations initialized at large scales and with wavevectors that are highly oblique with respect to the background magnetic field evolve into a turbulent energy cascade that dissipates at proton kinetic scales. Accompanying the proton scales is a spectral magnetic helicity signature with a peak in magnitude. A series of simulation runs are made with different large-scale cross helicity and different initial fluctuation phases and wavevector configurations. From the simulations a so-called total magnetic helicity peak is evaluated by summing contributions at a wavenumber perpendicular to the background magnetic field. The total is then compared with the reduced magnetic helicity calculated along spacecraft-like trajectories through the simulation box. The reduced combines the helicity from different perpendicular wavenumbers and depends on the sampling direction. The total is then the better physical quantity to characterize the turbulence. On average the ratio of reduced to total is 0.45. The total magnetic helicity and the reduced magnetic helicity show intrinsic variability based on initial fluctuation conditions. This variability can contribute to the scatter found in the observed distribution of solar wind reduced magnetic helicity as a function of cross helicity.
Dark Energy Survey Year 3 Results: Measuring the Survey Transfer Function with Balrog
Authors: Everett S. , Yanny B. , Kuropatkin N. , Huff E. M. , Zhang Y. , Myles J. , Masegian A. , Elvin-Poole J. , Allam S. , Bernstein G. M. , Sevilla-Noarbe I. , Splettstoesser M. , Sheldon E. , Jarvis M. , Amon A. , Harrison I. , Choi A. , Hartley W. G. , Alarcon A. , Sánchez C. , Gruen D. , Eckert K. , Prat J. , Tabbutt M. , Busti V. , Becker M. R. , MacCrann N. , Diehl H. T. , Tucker D. L. , Bertin E. , Jeltema T. , Drlica-Wagner A. , Gruendl R. A. , Bechtol K. , Rosell A. Carnero , Abbott T. M. C. , Aguena M. , Annis J. , Bacon D. , Bhargava S. , Brooks D. , Burke D. L. , Kind M. Carrasco , Carretero J. , Castander F. J. , Conselice C. , Costanzi M. , da Costa L. N. , Pereira M. E. S. , De Vicente J. , DeRose J. , Desai S. , Eifler T. F. , Evrard A. E. , Ferrero I. , Fosalba P. , Frieman J. , García-Bellido J. , Gaztanaga E. , Gerdes D. W. , Gutierrez G. , Hinton S. R. , Hollowood D. L. , Honscheid K. , Huterer D. , James D. J. , Kent S. , Krause E. , Kuehn K. , Lahav O. , Lima M. , Lin H. , Maia M. A. G. , Marshall J. L. , Melchior P. , Menanteau F. , Miquel R. , Mohr J. J. , Morgan R. , Muir J. , Ogando R. L. C. , Palmese A. , Paz-Chinchón F. , Plazas A. A. , Rodriguez-Monroy M. , Romer A. K. , Roodman A. , Sanchez E. , Scarpine V. , Serrano S. , Smith M. , Soares-Santos M. , Suchyta E. , Swanson M. E. C. , Tarle G. , To C. , Troxel M. A. , Varga T. N. , Weller J. , Wilkinson R. D. ,   (DES Collaboration)
Published: January 2022

We describe an updated calibration and diagnostic framework, Balrog, used to directly sample the selection and photometric biases of the Dark Energy Survey (DES) Year 3 (Y3) data set. We systematically inject onto the single-epoch images of a random 20% subset of the DES footprint an ensemble of nearly 30 million realistic galaxy models derived from DES Deep Field observations. These augmented images are analyzed in parallel with the original data to automatically inherit measurement systematics that are often too difficult to capture with generative models. The resulting object catalog is a Monte Carlo sampling of the DES transfer function and is used as a powerful diagnostic and calibration tool for a variety of DES Y3 science, particularly for the calibration of the photometric redshifts of distant “source” galaxies and magnification biases of nearer “lens” galaxies. The recovered Balrog injections are shown to closely match the photometric property distributions of the Y3 GOLD catalog, particularly in color, and capture the number density fluctuations from observing conditions of the real data within 1% for a typical galaxy sample. We find that Y3 colors are extremely well calibrated, typically within ∼1–8 mmag, but for a small subset of objects, we detect significant magnitude biases correlated with large overestimates of the injected object size due to proximity effects and blending. We discuss approaches to extend the current methodology to capture more aspects of the transfer function and reach full coverage of the survey footprint for future analyses.
TESS Eclipsing Binary Stars. I. Short-cadence Observations of 4584 Eclipsing Binaries in Sectors 1–26
Authors: Prša Andrej , Kochoska Angela , Conroy Kyle E. , Eisner Nora , Hey Daniel R. , IJspeert Luc , Kruse Ethan , Fleming Scott W. , Johnston Cole , Kristiansen Martti H. , LaCourse Daryll , Mortensen Danielle , Pepper Joshua , Stassun Keivan G. , Torres Guillermo , Abdul-Masih Michael , Chakraborty Joheen , Gagliano Robert , Guo Zhao , Hambleton Kelly , Hong Kyeongsoo , Jacobs Thomas , Jones David , Kostov Veselin , Lee Jae Woo , Omohundro Mark , Orosz Jerome A. , Page Emma J. , Powell Brian P. , Rappaport Saul , Reed Phill , Schnittman Jeremy , Schwengeler Hans Martin , Shporer Avi , Terentev Ivan A. , Vanderburg Andrew , Welsh William F. , Caldwell Douglas A. , Doty John P. , Jenkins Jon M. , Latham David W. , Ricker George R. , Seager Sara , Schlieder Joshua E. , Shiao Bernie , Vanderspek Roland , Winn Joshua N.
Published: January 2022

In this paper we present a catalog of 4584 eclipsing binaries observed during the first two years (26 sectors) of the TESS survey. We discuss selection criteria for eclipsing binary candidates, detection of hitherto unknown eclipsing systems, determination of the ephemerides, the validation and triage process, and the derivation of heuristic estimates for the ephemerides. Instead of keeping to the widely used discrete classes, we propose a binary star morphology classification based on a dimensionality reduction algorithm. Finally, we present statistical properties of the sample, we qualitatively estimate completeness, and we discuss the results. The work presented here is organized and performed within the TESS Eclipsing Binary Working Group, an open group of professional and citizen scientists; we conclude by describing ongoing work and future goals for the group. The catalog is available from http://tessEBs.villanova.edu and from MAST.
Ammonia Emission in Various Star-forming Environments: A Pilot Study of Planck Galactic Cold Clumps
Authors: Fehér O. , Tóth L. Viktor , Kraus Alex , Bőgner Rebeka , Kim Gwanjeong , Liu Tie , Tatematsu Ken’ichi , Tóth Victor , Eden David J. , Hirano Naomi , Juvela Mika , Kim Kee-Tae , Li Di , Liu Sheng-Yuan , Wu Yuefang ,   The TOP-SCOPE Collaboration
Published: January 2022

The Planck Catalogue of Galactic Cold Clumps provides an all-sky sample of potential star-forming regions based on the submillimeter emission of their dust content. Around 1000 of these Planck objects were mapped with the James Clerk Maxwell telescope in the submillimeter range during the SCOPE survey, identifying prestellar and protostellar dense clumps inside them. We used the Effelsberg 100 m telescope to observe the emission lines of the NH3 inversion transitions toward a sample of 97 dense objects in varying environments in order to assess the physical parameters of their gas content. We derive their temperature, density, and velocity dispersion, correlating the resulting parameters with the environmental and evolutionary characteristics of the targets and with regard to their distance and physical size. We examine the dependence of physical parameters on distance and Galactic position and compare the gas-based and dust-continuum-based temperatures and densities. Together with the presence of maser emission and higher inversion transitions of ammonia, we may differentiate between certain groups of targets, e.g., filamentary, protostellar clumps, and high-latitude, core-sized, starless sources.
A New Discrete Implicit Monte Carlo Scheme for Simulating Radiative Transfer Problems
Authors: Steinberg Elad , Heizler Shay I.
Published: January 2022

We present a new algorithm for radiative transfer—based on a statistical Monte Carlo approach—that does not suffer from teleportation effects, on the one hand, and yields smooth results, on the other hand. Implicit Monte Carlo (IMC) techniques for modeling radiative transfer have existed from the 1970s. When they are used for optically thick problems, however, the basic algorithm suffers from “teleportation” errors, where the photons propagate faster than the exact physical behavior, due to the absorption-blackbody emission processes. One possible solution is to use semianalog Monte Carlo, in its new implicit form (ISMC), which uses two kinds of particles, photons and discrete material particles. This algorithm yields excellent teleportation-free results, but it also produces noisier solutions (relative to classic IMC), due to its discrete nature. Here, we derive a new Monte Carlo algorithm, Discrete Implicit Monte Carlo (DIMC), which also uses the idea of two kinds of discrete particles, and thus does not suffer from teleportation errors. DIMC implements the IMC discretization and creates new radiation photons for each time step, unlike ISMC. Using the continuous absorption technique, DIMC yields smooth results like classic IMC. One of the main elements of the algorithm is the avoidance of the explosion of the particle population, by using particle merging. We test the new algorithm on 1D and 2D cylindrical problems, and show that it yields smooth, teleportation-free results. We finish by demonstrating the power of the new algorithm on a classic radiative hydrodynamic problem—an opaque radiative shock wave. This demonstrates the power of the new algorithm for astrophysical scenarios.
What Seismic Minimum Reveals about Solar Magnetism below the Surface
Authors: Jain Kiran , Jain Niket , Tripathy Sushanta C. , Dikpati Mausumi
Published: January 2022

The Sun’s magnetic field varies on multiple timescales. Observations show that the minimum between cycles 24 and 25 was the second consecutive minimum that was deeper and wider than several earlier minima. Since the active regions observed at the Sun’s surface are manifestations of the magnetic field generated in the interior, it is crucial to investigate/understand the dynamics below the surface. In this context, we report by probing the solar interior with helioseismic techniques applied to long-term oscillations data from the Global Oscillation Network Group, that the seismic minima in deeper layers have been occurring about a year earlier than that at the surface for the last two consecutive solar cycles. Our findings also demonstrate a decrease in strong magnetic fields at the base of the convection zone, the primary driver of the surface magnetic activity. We conclude that the magnetic fields located in the core and near-surface shear layers, in addition to the tachocline fields, play an important role in modifying the oscillation frequencies. This further strengthens the existence of a relic magnetic field in the Sun’s core.
Parker Solar Probe Evidence for the Absence of Whistlers Close to the Sun to Scatter Strahl and to Regulate Heat Flux
Authors: Cattell C. , Breneman A. , Dombeck J. , Hanson E. , Johnson M. , Halekas J. , Bale S. D. , Dudok de Wit T. , Goetz K. , Goodrich K. , Malaspina D. , Pulupa M. , Case T. , Kasper J. C. , Larson D. , Stevens M. , Whittlesey P.
Published: January 2022

Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from ∼16 R
s to ∼130 R
s, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside ∼28 R
s (∼0.13 au). Outside 28 R
s, they occur within a narrow range of parallel electron beta from ∼1 to 10, and with a beta-heat flux occurrence consistent with the whistler heat flux fan instability. Because electron distributions inside ∼30 R
s display signatures of the ambipolar electric field, the lack of whistlers suggests that the modification of the electron distribution function associated with the ambipolar electric field or changes in other plasma properties must result in lower instability limits for the other modes (including the observed solitary waves and ion acoustic waves) that are observed close to the Sun. The lack of narrowband whistler-mode waves close to the Sun and in regions of either low (<0.1) or high (>10) beta is also significant for the understanding and modeling of the evolution of flare-accelerated electrons and the regulation of heat flux in astrophysical settings including other stellar winds, the interstellar medium, accretion disks, and the intragalaxy cluster medium.
Three-Dimensional Anisotropy and Scaling Properties of Solar Wind Turbulence at Kinetic Scales in the Inner Heliosphere: Parker Solar Probe Observations
Authors: Zhang J. , Huang S. Y. , He J. S. , Wang T. Y. , Yuan Z. G. , Deng X. H. , Jiang K. , Wei Y. Y. , Xu S. B. , Xiong Q. Y. , Lin R. T. , Yu L.
Published: January 2022

We utilize the data from the Parker Solar Probe mission at its first perihelion to investigate the three-dimensional (3D) anisotropies and scalings of solar wind turbulence for the total, perpendicular, and parallel magnetic-field fluctuations at kinetic scales in the inner heliosphere. By calculating the five-point second-order structure functions, we find that the three characteristic lengths of turbulence eddies for the total and the perpendicular magnetic-field fluctuations in the local reference frame

(

L

ˆ

⊥

,

l

ˆ

⊥

,

l

ˆ

∣
∣

)

defined with respect to the local mean magnetic field
B

local feature as l
∣∣ > L
⊥ > l
⊥ in both the transition range and the ion-to-electron scales, but l
∣∣ > L
⊥ ≈ l
⊥ for the parallel magnetic-field fluctuations. For the total magnetic-field fluctuations, the wave-vector anisotropy scalings are characterized by

l

∣
∣

∝

l

⊥

0.78

and

L

⊥

∝

l

⊥

1.02

in the transition range, and they feature as

l

∣
∣

∝

l

⊥

0.44

and

L

⊥

∝

l

⊥

0.73

in the ion-to-electron scales. Still, we need more complete kinetic-scale turbulence models to explain all these observational results.
The Appearance of a “Fresh” Surface on 596 Scheila as a Consequence of the 2010 Impact Event
Authors: Hasegawa Sunao , Marsset Michaël , DeMeo Francesca E. , Bus Schelte J. , Ishiguro Masateru , Kuroda Daisuke , Binzel Richard P. , Hanuš Josef , Nakamura Akiko M. , Yang Bin , Vernazza Pierre
Published: January 2022

Dust emission was detected on main-belt asteroid 596 Scheila in 2010 December and was attributed to the collision of a few-tens-of-meters projectile on the surface of the asteroid. In such an impact, the ejected material from the collided body is expected to mainly come from its fresh, unweathered subsurface. Therefore, it is expected that the surface of 596 was partially or entirely refreshed during the 2010 impact. By combining spectra of 596 from the literature and our own observations, we show that the 2010 impact event resulted in a significant slope change in the near-infrared (0.8–2.5 μm) spectrum of the asteroid, from moderately red (T type) before the impact to red (D type) after the impact. This provides evidence that red carbonaceous asteroids become less red with time due to space weathering, in agreement with predictions derived from laboratory experiments on the primitive Tagish Lake meteorite, which is spectrally similar to 596. This discovery provides the very first telescopic confirmation of the expected weathering trend of asteroids spectrally analog to Tagish Lake and/or anhydrous chondritic porous interplanetary dust particles. Our results also suggest that the population of implanted objects from the outer solar system is much larger than previously estimated in the main belt, but many of these objects are hidden below their space-weathered surfaces.
Observational Signatures of Tearing Instability in the Current Sheet of a Solar Flare
Authors: Lu Lei , Feng Li , Warmuth Alexander , Veronig Astrid M. , Huang Jing , Liu Siming , Gan Weiqun , Ning Zongjun , Ying Beili , Gao Guannan
Published: January 2022

Magnetic reconnection is a fundamental physical process converting magnetic energy into not only plasma energy but also particle energy in various astrophysical phenomena. In this Letter, we show a unique data set of a solar flare where various plasmoids were formed by a continually stretched current sheet. Extreme ultraviolet images captured reconnection inflows, outflows, and particularly the recurring plasma blobs (plasmoids). X-ray images reveal nonthermal emission sources at the lower end of the current sheet, presumably as large plasmoids with a sufficiently amount of energetic electrons trapped in them. In the radio domain, an upward, slowly drifting pulsation structure, followed by a rare pair of oppositely drifting structures, was observed. These structures are supposed to map the evolution of the primary and the secondary plasmoids formed in the current sheet. Our results on plasmoids at different locations and scales shed important light on the dynamics, plasma heating, particle acceleration, and transport processes in the turbulent current sheet and provide observational evidence for the cascading magnetic reconnection process.
Multipoint Interplanetary Coronal Mass Ejections Observed with Solar Orbiter, BepiColombo, Parker Solar Probe, Wind, and STEREO-A
Authors: Möstl Christian , Weiss Andreas J. , Reiss Martin A. , Amerstorfer Tanja , Bailey Rachel L. , Hinterreiter Jürgen , Bauer Maike , Barnes David , Davies Jackie A. , Harrison Richard A. , Freiherr von Forstner Johan L. , Davies Emma E. , Heyner Daniel , Horbury Tim , Bale Stuart D.
Published: January 2022

We report the result of the first search for multipoint in situ and imaging observations of interplanetary coronal mass ejections (ICMEs) starting with the first Solar Orbiter (SolO) data in 2020 April–2021 April. A data exploration analysis is performed including visualizations of the magnetic-field and plasma observations made by the five spacecraft SolO, BepiColombo, Parker Solar Probe (PSP), Wind, and STEREO-A, in connection with coronagraph and heliospheric imaging observations from STEREO-A/SECCHI and SOHO/LASCO. We identify ICME events that could be unambiguously followed with the STEREO-A heliospheric imagers during their interplanetary propagation to their impact at the aforementioned spacecraft and look for events where the same ICME is seen in situ by widely separated spacecraft. We highlight two events: (1) a small streamer blowout CME on 2020 June 23 observed with a triple lineup by PSP, BepiColombo and Wind, guided by imaging with STEREO-A, and (2) the first fast CME of solar cycle 25 (≈1600 km s−1) on 2020 November 29 observed in situ by PSP and STEREO-A. These results are useful for modeling the magnetic structure of ICMEs and the interplanetary evolution and global shape of their flux ropes and shocks, and for studying the propagation of solar energetic particles. The combined data from these missions are already turning out to be a treasure trove for space-weather research and are expected to become even more valuable with an increasing number of ICME events expected during the rise and maximum of solar cycle 25.
Evidence for Gamma-Ray Pulsations from the Classical Nova ASASSN-16ma
Authors: Li Kwan-Lok
Published: January 2022

I report here a new result extracted from the Fermi Large Area Telescope observation of the classical nova ASASSN-16ma that exhibits coherent γ-ray pulsations at 544.84(7) s during its outburst in 2016. Considering the number of independent trials, the significance of the evidence is 4.0σ, equivalent to a false-alarm probability of 5.9 × 10−5. The periodicity was steady during the 4 days of its appearance, indicating its origin as the spinning signal of the white dwarf. Given that the optical and γ-ray light curves of some shock-powered γ-ray novae have been recently shown to be closely correlated to each other, the γ-ray pulsation phenomenon likely implies an existence of associated optical pulsations, which would provide detailed ephemerides for these extreme white dwarf binaries for further investigations in the near future.
Magnetic Field Amplification by a Plasma Cavitation Instability in Relativistic Shock Precursors
Authors: Peterson J. R. , Glenzer S. , Fiuza F.
Published: January 2022

Plasma streaming instabilities play an important role in magnetic field amplification and particle acceleration in relativistic shocks and their environments. However, in the far shock precursor region where accelerated particles constitute a highly relativistic and dilute beam, streaming instabilities typically become inefficient and operate at very small scales when compared to the gyroradii of the beam particles. We report on a plasma cavitation instability that is driven by dilute relativistic beams and can increase both the magnetic field strength and coherence scale by orders of magnitude to reach near-equipartition values with the beam energy density. This instability grows after the development of the Weibel instability and is associated with the asymmetric response of background leptons and ions to the beam current. The resulting net inductive electric field drives a strong energy asymmetry between positively and negatively charged beam species. Large-scale particle-in-cell simulations are used to verify analytical predictions for the growth and saturation level of the instability and indicate that it is robust over a wide range of conditions, including those associated with pair-loaded plasmas. These results can have important implications for the magnetization and structure of shocks in gamma-ray bursts, and more generally for magnetic field amplification and asymmetric scattering of relativistic charged particles in plasma astrophysical environments.
Evidence for Plasma Heating at Thin Current Sheets in the Solar Wind
Authors: Zhou Zilu , Xu Xiaojun , Zuo Pingbing , Wang Yi , Xu Qi , Ye Yudong , Wang Jing , Wang Ming , Chang Qing , Wang Xing , Luo Lei
Published: January 2022

Plasma heating at thin current sheets in the solar wind is examined using magnetic field and plasma data obtained by the WIND spacecraft in the past 17 years from 2004 to 2019. In this study, a thin current sheet is defined by an abrupt rotation (larger than 45°) of the magnetic field direction in 3 s. A total of 57,814 current sheets have been identified, among which 25,018 current sheets are located in the slow wind and 19,842 current sheets are located in the fast wind. Significant plasma heating is found at current sheets in both slow and fast wind. Proton temperature increases more significantly at current sheets in the fast wind than in the slow wind, while the enhancement in electron temperature is less remarkable at current sheets in the fast wind. The results reveal that plasma heating commonly exists at thin current sheets in the solar wind regardless of the wind speed, but the underlying heating mechanisms might be different.
A Robust Estimation of Lorentz Invariance Violation and Intrinsic Spectral Lag of Short Gamma-Ray Bursts
Authors: Xiao Shuo , Xiong Shao-Lin , Wang Yue , Zhang Shuang-Nan , Gao He , Zhang Zhen , Cai Ce , Yi Qi-Bin , Zhao Yi , Tuo You-Li , Li Xin-Qiao , Wen Xiang-Yang , An Zheng-Hua , Peng Wen-Xi , Zheng Shi-Jie , Zhang Fan , Song Li-Ming , Li Ti-Pei
Published: January 2022

Gamma-ray bursts (GRBs) have been identified as one of the most promising sources for Lorentz invariance violation (LIV) studies due to their cosmological distance and energetic emission in wide energy bands. However, the arrival-time difference of GRB photons among different energy bands is affected not only by the LIV effect but also by the poorly known intrinsic spectral lags. In previous studies, assumptions of spectral lag have to be made which could introduce systematic errors. In this paper, we used a sample of 46 short GRBs (SGRBs), whose intrinsic spectra lags are much smaller than long GRBs, to better constrain the LIV. The observed spectral lags are derived between two fixed energy bands in the source rest frame rather than the observer frame. Moreover, the lags are calculated with the novel Li–CCF method, which is more robust than traditional methods. Our results show that, if we consider LIV as a linear energy dependence of the photon propagation speed in the data fit, then we obtain a robust limit of E
QG > 1015 GeV (95% CL). If we assume no LIV effect in the keV–MeV energy range, the goodness of data fit is equivalently as well as the case with LIV and we can constrain the common intrinsic spectral lags of SGRBs to be 1.4 ± 0.5 ms (1σ), which is the most accurate measurement thus far.
L’Orna : une expertise construite à partir de nombreuses collaborations
Authors: Ferrand Marie-Hélène
Published: January 2022

Dans la continuité du précédent, cet article rassemble trois témoignages de professionnels qui ont participé à des actions dans lesquelles l’Observatoire des ressources numériques adaptées (Orna) s’est investi, au service de la scolarisation de tous les élèves.
Influence of drought stress on growth, biochemical changes and leaf gas exchange of strawberry (Fragaria × ananassa Duch.) in Indonesia
Authors: Yenni  , Ibrahim Mohd Hafiz , Nulit Rosimah , Sakimin Siti Zaharah
Published: January 2022

Drought stress is one of the challenges that can affect the growth and the quality of strawberry. The study aims to determine the growth, biochemical changes and leaf gas exchange of three strawberry cultivars under drought stress. This study was conducted in a glasshouse at Indonesian Citrus and Subtropical Fruits Research Institute, Indonesia, from July-November 2018. The experiment was arranged in a factorial randomized completely block design (RCBD) with three replications and four water deficit (WD) levels [100% field capacity (FC)/well-watered), 75% of FC (mild WD), 50% of FC (moderate WD), and 25% of FC (severe WD)] for three strawberry cultivars (Earlibrite, California and Sweet Charlie). The results showed that total chlorophyll and anthocyanin contents (p ≤ 0.05) were influenced by the interaction effects of cultivars and water deficit. Whereas other parameters such as plant growth, transpiration rate (E), net photosynthesis (A), stomatal conductance (gs), leaf relative water content (LRWC), flowers and fruits numbers, proline content, length, diameter, weight and total soluble solid (TSS) of fruit were affected by water deficit. A had positive significant correlation with plant height (r = 0.808), leaf area (r = 0.777), fruit length (r = 0.906), fruit diameter (r = 0.889) and fruit weight (r = 0.891). Based on the results, cultivars affected LRWC, and also number of flowers and fruits of the strawberry. This study showed that water deficit decreased plant growth, chlorophyll content, leaf gas exchange, leaf relative water content, length, diameter and weight of fruit but enhanced TSS, anthocyanin, MDA, and proline contents. Increased anthocyanin and proline contents are mechanisms for protecting plants against the effects of water stress. California strawberry had the highest numbers of flowers and fruits, and also anthocyanin content. Hence, this cultivar is recommended to be planted under drought stress conditions. Among all water stress treatments, 75% of FC had the best results to optimize water utilization on the strawberry plants.
Millimetre wave 3-D channel modelling for next generation 5G networks
Authors: Saba'neh Latih ,   Cisco Systems Netherlands Holding BV-KHBP, Haarlerbergweg 13, Amsterdam Zuidoost, 1101CH, Amsterdam, Al-Khatib Obada ,   Faculty of Engineering and Information Sciences, University of Wollongong in Dubai, Dubai Knowledge Village, Dubai, 20183, UAE
Published: January 2022

Millimetre wave (mm-wave) spectrum (30-300GHz) is a key enabling technology in the advent of 5G. However, an accurate model for the mm-wave channel is yet to be developed as the existing 4G-LTE channel models (frequency below 6 GHz) exhibit different propagation attributes. In this paper, a spatial statistical channel model (SSCM) is considered that estimates the characteristics of the channel in the 28, 60, and 73 GHz bands. The SSCM is used to mathematically approximate the propagation path loss in different environments, namely, Urban-Macro, Urban-Micro, and Rural-Macro, under Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) conditions. The New York University (NYU) channel simulator is utilised to evaluate the channel model under various conditions including atmospheric effects, distance, and frequency. Moreover, a MIMO system has been evaluated under mm-wave propagation. The main results show that the 60 GHz band has the highest attenuation compared to the 28 and 73 GHz bands. The results also show that increasing the number of antennas is proportional to the condition number and the rank of the MIMO channel matrix.
Weighted and endpoint estimates for commutators of bilinear pseudo-differential operators
Authors: Yang Yanqi ,   College of Mathematics and Statistics, Northwest Normal University, Lanzhou 730070, China, Tao Shuangping , Lu Guanghui
Published: January 2022

In this paper, by applying the accurate estimates of the Hörmander class, the authors consider the commutators of bilinear pseudo-differential operators and the operation of multiplication by a Lipschitz function. By establishing the pointwise estimates of the corresponding sharp maximal function, the boundedness of the commutators is obtained respectively on the products of weighted Lebesgue spaces and variable exponent Lebesgue spaces with $ \sigma \in\mathcal{B}BS_{1, 1}^{1} $. Moreover, the endpoint estimate of the commutators is also established on $ L^{\infty}\times L^{\infty} $.
Numerical differentiation for two-dimensional scattered data on arbitrary domain base on Hermite extension with an implicit iteration process
Authors: Gong Benxue ,   School of Mathematics and Statistics, Shandong University of Technology, Zibo, 255049, China, Zhao Zhenyu , Bian Tiao , Wang Yingmei ,   Shandong Gpcmarket Info Tech Co., Ltd, Weifang, 261000, China
Published: January 2022

In this paper, we develop a method for numerical differentiation of two-dimensional scattered input data on arbitrary domain. A Hermite extension approach is used to realize the approximation and a modified implicit iteration method is proposed to stabilize the approximation process. For functions with various smooth conditions, the numerical solution process of the method is uniform. The error estimates are obtained and numerical results show that the new method is effective. The advantage of the method is that it can solve the problem in any domain.
The number of COVID-19 clusters in healthcare and elderly care facilities averted by vaccination of healthcare workers in Japan, February–June 2021
Authors: Sasanami Misaki ,   Kyoto University School of Public Health, Yoshida-Konoe, Sakyo, Kyoto 606-8601, Japan, Kayano Taishi , Nishiura Hiroshi
Published: January 2022

In Japan, a prioritized COVID-19 vaccination program using Pfizer/BioNTech messenger RNA (mRNA) vaccine among healthcare workers commenced on February 17, 2021. As vaccination coverage increases, clusters in healthcare and elderly care facilities including hospitals and nursing homes are expected to be reduced. The present study aimed to explicitly estimate the protective effect of vaccination in reducing cluster incidence in those facilities. A mathematical model was formulated using three pieces of information: (1) the incidence of clusters in facilities from October 26, 2020 to June 27, 2021; (2) the incidence of confirmed COVID-19 cases during the same period; and (3) vaccine doses among healthcare workers from February 17 to June 27, 2021, extracted from the national Vaccination System database. We found that the estimated proportion at risk in healthcare and elderly care facilities declined substantially as the vaccination coverage among healthcare workers increased; the greater risk reduction was observed in healthcare facilities, at 0.10 (95% confidence interval (CI): 0.04–0.16) times that in the pre-vaccination period, while that in elderly care facilities was 0.34 (95% CI: 0.24–0.43) times that in the earlier period. The averted numbers of clusters in healthcare facilities and elderly care facilities were estimated to be 247 (95% CI: 210–301) and 279 (95% CI: 218–354), respectively. Prioritized vaccination among healthcare workers had a marked impact on preventing the incidence of clusters in facilities.
Effect of selenium and zinc foliar application to increase the quantitative and qualitative yields of rapeseed at different sowing dates
Authors: Goharian A. , Shirani Rad A.H. , Moaveni P. , Mozafari H. , Sani B.
Published: January 2022

The sowing date is an important factor for expanding the cultivated area of rapeseed and affects seed yield, oil content, and fatty acid compounds. Micronutrient elements play an important role in improving the vegetative and reproductive growth of the plant, especially under conditions of biological and environmental stresses. A two-year experiment (2014-2016) was performed to study the response of rapeseed genotypes to foliar application of micronutrients on different sowing dates. The treatments were arranged as a factorial-split plot in a randomized complete block design with three replicates. Three sowing dates of 7 (well-timed sowing date), 17, and 27 (delayed sowing dates) October and two levels of foliar application with pure water (control), selenium (1.5%), zinc (1.5%), and selenium+zinc (1.5%) were factorial in the main plots and five genotypes of SW102, Ahmadi, GKH2624, GK-Gabriella, and Okapi were randomized in the subplots (a total of 30 treatments). Seed yield, oil yield and content, oleic acid, and linoleic acid were reduced when rapeseeds were cultivated on 17 and 27 October, while the contents in palmitic, linolenic, and erucic acids, and glucosinolate increased (p < 0.01). a selenium+zinc treatment improved seed yield, oil content and yield (p < 0.01). The oil quality increased due to increased contents of oleic and linoleic acids under the selenium+zinc treatment (p < 0.01). The GK-Gabriella and GKH2624 genotypes are recommended to be sown on well-timed (7 October) and delayed sowing dates (17 and 27 October) and treated with selenium+zinc due to the higher oil yield, linoleic and oleic acids.