Gaia Early Data Release 3 Lindegren, L.; Klioner, S. A.; Hernández, J. ...
Astronomy and astrophysics (Berlin),
05/2021, Letnik:
649
Journal Article
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Context. Gaia
Early Data Release 3 (
Gaia
EDR3) contains results for 1.812 billion sources in the magnitude range
G
= 3–21 based on observations collected by the European Space Agency
Gaia
satellite ...during the first 34 months of its operational phase.
Aims.
We describe the input data, the models, and the processing used for the astrometric content of
Gaia
EDR3, as well as the validation of these results performed within the astrometry task.
Methods.
The processing broadly followed the same procedures as for
Gaia
DR2, but with significant improvements to the modelling of observations. For the first time in the
Gaia
data processing, colour-dependent calibrations of the line- and point-spread functions have been used for sources with well-determined colours from DR2. In the astrometric processing these sources obtained five-parameter solutions, whereas other sources were processed using a special calibration that allowed a pseudocolour to be estimated as the sixth astrometric parameter. Compared with DR2, the astrometric calibration models have been extended, and the spin-related distortion model includes a self-consistent determination of basic-angle variations, improving the global parallax zero point.
Results. Gaia
EDR3 gives full astrometric data (positions at epoch J2016.0, parallaxes, and proper motions) for 1.468 billion sources (585 millionwith five-parameter solutions, 882 million with six parameters), and mean positions at J2016.0 for an additional 344 million.Solutions with five parameters are generally more accurate than six-parameter solutions, and are available for 93% of the sources brighter than the 17th magnitude. The median uncertainty in parallax and annual proper motion is 0.02–0.03 mas at magnitude
G
= 9–14, and around 0.5 mas at
G
= 20. Extensive characterisation of the statistical properties of the solutions is provided, including the estimated angular power spectrum of parallax bias from the quasars.
Bacterial pathogens resistant to antibiotics have become a serious health threat. Those species which have developed resistance against multiple drugs such as the carbapenems, are more lethal as ...these are last line therapy antibiotics. Current diagnostic tests for these resistance traits are based on singleplex target amplification techniques which can be time consuming and prone to errors. Here, we demonstrate a chip based optofluidic system with single molecule sensitivity for amplification-free, multiplexed detection of plasmids with genes corresponding to antibiotic resistance, within one hour. Rotating disks and microfluidic chips with functionalized polymer monoliths provided the upstream sample preparation steps to selectively extract these plasmids from blood spiked with E. coli DH5α cells. Waveguide-based spatial multiplexing using a multi-mode interference waveguide on an optofluidic chip was used for parallel detection of three different carbapenem resistance genes. These results point the way towards rapid, amplification-free, multiplex analysis of antibiotic-resistant pathogens.
We present high-precision multiband photometry for the globular cluster (GC) M2. We combine the analysis of the photometric data obtained from the Hubble Space Telescope UV Legacy Survey of Galactic ...GCs GO-13297, with chemical abundances by Yong et al., and compare the photometry with models in order to analyse the multiple stellar sequences we identified in the colour–magnitude diagram. We find three main stellar components, composed of metal-poor, metal-intermediate, and metal-rich stars (hereafter referred to as population A, B, and C, respectively). The components A and B include stars with different s-process element abundances. They host six sub-populations with different light-element abundances, and exhibit an internal variation in helium up to ΔY ∼ 0.07 dex. In contrast with M22, another cluster characterized by the presence of populations with different metallicities, M2 contains a third stellar component, C, which shows neither evidence for sub-populations nor an internal spread in light-elements. Population C does not exhibit the typical photometric signatures that are associated with abundance variations of light elements produced by hydrogen burning at hot temperatures. We compare M2 with other GCs with intrinsic heavy-element variations and conclude that M2 resembles M22, but it includes an additional stellar component that makes it more similar to the central region of the Sagittarius galaxy, which hosts a GC (M54) and the nucleus of the Sagittarius galaxy itself.
The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum ...states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).
On April 1st, 2019, the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO), joined by the Advanced Virgo detector, began the third observing run, a year-long dedicated search for ...gravitational radiation. The LIGO detectors have achieved a higher duty cycle and greater sensitivity to gravitational waves than ever before, with LIGO Hanford achieving angle-averaged sensitivity to binary neutron star coalescences to a distance of 111 Mpc, and LIGO Livingston to 134 Mpc with duty factors of 74.6% and 77.0% respectively. The improvement in sensitivity and stability is a result of several upgrades to the detectors, including doubled intracavity power, the addition of an in-vacuum optical parametric oscillator for squeezed-light injection, replacement of core optics and end reaction masses, and installation of acoustic mode dampers. This paper explores the purposes behind these upgrades, and explains to the best of our knowledge the noise currently limiting the sensitivity of each detector.
We calculate the up-, down-, strange-, charm-, and bottom-quark masses using the MILC highly improved staggered-quark ensembles with four flavors of dynamical quarks. We use ensembles at six lattice ...spacings ranging from a≈0.15 to 0.03 fm and with both physical and unphysical values of the two light and the strange sea-quark masses. We use a new method based on heavy-quark effective theory (HQET) to extract quark masses from heavy-light pseudoscalar meson masses. Combining our analysis with our separate determination of ratios of light-quark masses we present masses of the up, down, strange, charm, and bottom quarks. Our results for the MS¯-renormalized masses are mu(2 GeV)=2.130(41) MeV, md(2 GeV)=4.675(56) MeV, ms(2 GeV)=92.47(69) MeV, mc(3 GeV)=983.7(5.6) MeV, and mc(mc)=1273(10) MeV, with four active flavors; and mb(mb)=4195(14) MeV with five active flavors. We also obtain ratios of quark masses mc/ms=11.783(25), mb/ms=53.94(12), and mb/mc=4.578(8). The result for mc matches the precision of the most precise calculation to date, and the other masses and all quoted ratios are the most precise to date. Moreover, these results are the first with a perturbative accuracy of αs4. As byproducts of our method, we obtain the matrix elements of HQET operators with dimension 4 and 5: Λ¯MRS=555(31) MeV in the minimal renormalon-subtracted (MRS) scheme, μπ2=0.05(22) GeV2, and μG2(mb)=0.38(2) GeV2. The MRS scheme Phys. Rev. D 97, 034503 (2018) is the key new aspect of our method.
Summary Background Animals can act as a reservoir and source for the emergence of novel meticillin-resistant Staphylococcus aureus (MRSA) clones in human beings. Here, we report the discovery of a ...strain of S aureus (LGA251) isolated from bulk milk that was phenotypically resistant to meticillin but tested negative for the mecA gene and a preliminary investigation of the extent to which such strains are present in bovine and human populations. Methods Isolates of bovine MRSA were obtained from the Veterinary Laboratories Agency in the UK, and isolates of human MRSA were obtained from diagnostic or reference laboratories (two in the UK and one in Denmark). From these collections, we searched for mecA PCR-negative bovine and human S aureus isolates showing phenotypic meticillin resistance. We used whole-genome sequencing to establish the genetic basis for the observed antibiotic resistance. Findings A divergent mecA homologue ( mecALGA251 ) was discovered in the LGA251 genome located in a novel staphylococcal cassette chromosome mec element, designated type-XI SCC mec . The mecALGA251 was 70% identical to S aureus mecA homologues and was initially detected in 15 S aureus isolates from dairy cattle in England. These isolates were from three different multilocus sequence type lineages (CC130, CC705, and ST425); spa type t843 (associated with CC130) was identified in 60% of bovine isolates. When human mecA -negative MRSA isolates were tested, the mecALGA251 homologue was identified in 12 of 16 isolates from Scotland, 15 of 26 from England, and 24 of 32 from Denmark. As in cows, t843 was the most common spa type detected in human beings. Interpretation Although routine culture and antimicrobial susceptibility testing will identify S aureus isolates with this novel mecA homologue as meticillin resistant, present confirmatory methods will not identify them as MRSA. New diagnostic guidelines for the detection of MRSA should consider the inclusion of tests for mecALGA251. Funding Department for Environment, Food and Rural Affairs, Higher Education Funding Council for England, Isaac Newton Trust (University of Cambridge), and the Wellcome Trust.
Five, daily, gridded, Northern Hemisphere snow water equivalent (SWE) datasets are analyzed over the 1981–2010 period in order to quantify the spatial and temporal consistency of satellite ...retrievals, land surface assimilation systems, physical snow models, and reanalyses. While the climatologies of total Northern Hemisphere snow water mass (SWM) vary among the datasets by as much as 50%, their interannual variability and daily anomalies are comparable, showing moderate to good temporal correlations (between 0.60 and 0.85) on both interannual and intraseasonal time scales. Wintertime trends of total Northern Hemisphere SWM are consistently negative over the 1981–2010 period among the five datasets but vary in strength by a factor of 2–3. Examining spatial patterns of SWE indicates that the datasets are most consistent with one another over boreal forest regions compared to Arctic and alpine regions. Additionally, the datasets derived using relatively recent reanalyses are strongly correlated with one another and show better correlations with the satellite product the European Space Agency (ESA)’s Global Snow Monitoring for Climate Research (GlobSnow) than do those using older reanalyses. Finally, a comparison of eight reanalysis datasets over the 2001–10 period shows that land surface model differences control the majority of spread in the climatological value of SWM, while meteorological forcing differences control the majority of the spread in temporal correlations of SWM anomalies.
We report on a scale determination with gradient-flow techniques on the N sub(functionof)=2+1+1 highly improved staggered quark ensembles generated by the MILC Collaboration. The ensembles include ...four lattice spacings, ranging from approximately 0.15 to 0.06 fm, and both physical and unphysical values of the quark masses. The scales radicalt sub(0)/a and w sub(0)/a and their tree-level improvements, radicalt sub(0,imp) and w sub(0,imp), are computed on each ensemble using Symanzik flow and the cloverleaf definition of the energy density E. Using a combination of continuum chiral-perturbation theory and a Taylor-series ansatz for the lattice-spacing and strong-coupling dependence, the results are simultaneously extrapolated to the continuum and interpolated to physical quark masses. We determine the scales (ProQuest: Formulae and/or non-USASCII text omitted)and (ProQuest: Formulae and/or non-USASCII text omitted), where the errors are sums, in quadrature, of statistical and all systematic errors. The precision of w sub(0) and radicalt sub(0) is comparable to or more precise than the best previous estimates, respectively. We then find the continuum mass dependence of radicalt sub(0) and w sub(0), which will be useful for estimating the scales of new ensembles. We also estimate the integrated autocorrelation length of left angle bracketE(t)right angle bracket. For long flow times, the autocorrelation length of left angle bracketEright angle bracket appears to be comparable to that of the topological charge.
The MiniBooNE experiment at Fermilab reports results from an analysis of ν_{e} appearance data from 12.84×10^{20} protons on target in neutrino mode, an increase of approximately a factor of 2 over ...previously reported results. A ν_{e} charged-current quasielastic event excess of 381.2±85.2 events (4.5σ) is observed in the energy range 200<E_{ν}^{QE}<1250 MeV. Combining these data with the νover ¯_{e} appearance data from 11.27×10^{20} protons on target in antineutrino mode, a total ν_{e} plus νover ¯_{e} charged-current quasielastic event excess of 460.5±99.0 events (4.7σ) is observed. If interpreted in a two-neutrino oscillation model, ν_{μ}→ν_{e}, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a χ^{2} probability of 6×10^{-7} relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6.0σ. A two-neutrino oscillation interpretation of the data would require at least four neutrino types and indicate physics beyond the three neutrino paradigm. Although the data are fit with a two-neutrino oscillation model, other models may provide better fits to the data.
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