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Fukui, A.,Gould, A.,Sumi, T.,Bennett, D. P.,Bond, I. A.,Han, C.,Suzuki, D.,Beaulieu, J.-P.,Batista, V.,Udalski, A.,Street, R. A.,Tsapras, Y.,Hundertmark, M.,Abe, F.,Bhattacharya, A.,Freeman, M.,Itow, IOP Publishing 2015 The Astrophysical journal Vol.809 No.1
<P>We report the discovery of a microlensing exoplanet OGLE-2012-BLG-0563Lb with the planet-star mass ratio of similar to 1 x 10(-3). Intensive photometric observations of a high-magnification microlensing event allow us to detect a clear signal of the planet. Although no parallax signal is detected in the light curve, we instead succeed at detecting the flux from the host star in high-resolution JHK'-band images obtained by the Subaru/AO188 and Infrared Camera and Spectrograph instruments, allowing us to constrain the absolute physical parameters of the planetary system. With the help of spectroscopic information about the source star obtained during the high-magnification state by Bensby et al., we find that the lens system is located at 1.3(-0.8)(+0.6) kpc from us, and consists of an M dwarf (0.34(-0.20)(+0.12)M(circle dot)) orbited by a Saturn-mass planet (0.39(-0.23)(+0.14)M(Jup)) at the projected separation of 0.74(-0.42)(+0.26)AU (close model) or 4.3(-2.5)(+1.5)AU (wide model). The probability of contamination in the host star's flux, which would reduce the masses by a factor of up to three, is estimated to be 17%. This possibility can be tested by future high-resolution imaging. We also estimate the (J - K-s) and (H - K-s) colors of the host star, which are marginally consistent with a low metallicity mid-to-early M dwarf, although further observations are required for the metallicity to be conclusive. This is the fifth sub-Jupiter-mass (0.2 < m(p)/M-Jup < 1) microlensing planet around an M dwarf with the mass well constrained. The relatively rich harvest of sub-Jupiters around M dwarfs is contrasted with a possible paucity of similar to 1-2 Jupiter-mass planets around the same type of star, which can be explained by the planetary formation process in the core-accretion scheme.</P>
CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?
Freeman, M.,Philpott, L. C.,Abe, F.,Albrow, M. D.,Bennett, D. P.,Bond, I. A.,Botzler, C. S.,Bray, J. C.,Cherrie, J. M.,Christie, G. W.,Dionnet, Z.,Gould, A.,Han, C.,Heyrovský,, D.,McCormick, J. IOP Publishing 2015 The Astrophysical journal Vol.799 No.2
<P>Recently Sumi et al. reported evidence for a large population of planetary-mass objects ( PMOs) that are either unbound or orbit host stars in orbits >= 10 AU. Their result was deduced from the statistical distribution of durations of gravitational microlensing events observed by the MOA collaboration during 2006 and 2007. Here we study the feasibility of measuring the mass of an individual PMO through microlensing by examining a particular event, MOA-2011-BLG-274. This event was unusual as the duration was short, the magnification high, the source-size effect large, and the angular Einstein radius small. Also, it was intensively monitored from widely separated locations under clear skies at low air masses. Choi et al. concluded that the lens of the event may have been a PMO but they did not attempt a measurement of its mass. We report here a re-analysis of the event using re-reduced data. We confirm the results of Choi et al. and attempt a measurement of the mass and distance of the lens using the terrestrial parallax effect. Evidence for terrestrial parallax is found at a 3 sigma level of confidence. The best fit to the data yields the mass and distance of the lens as 0.80 +/- 0.30 M-J and 0.80 +/- 0.25 kpc respectively. We exclude a host star to the lens out to a separation similar to 40 AU. Drawing on our analysis of MOA-2011-BLG-274 we propose observational strategies for future microlensing surveys to yield sharper results on PMOs including those down to super-Earth mass.</P>
Seung-Woo Seo,You Young Song,Gul Rahman,In Gee Kim,M. Weinert,A. J. Freeman 한국자기학회 2009 Journal of Magnetics Vol.14 No.4
The convergence behavior of the all-electron full-potential linearized augmented plane-wave (FLAPW) method with the explicit orthogonalization (XO) scheme is tested on ferromagnetic bulk body-centered-cubic Fe. Applying a commonly used criterion relating the plane-wave and angular momentum cutoffs, lmax = RMTKmax, where RMT is the muffin-tin (MT) sphere radius and Kmax is the plane-wave cutoff for the basis ? the total energy is converged and stable for KmaxRMT = 10. The total energy convergence dependence on the star-function cutoff, Gmax, is minimal and so a Gmax of 3Kmax or a large enough Gmax is a reasonable choice. We demonstrate that the convergence with respect to lmax or a fixed large enough Gmax and Kmax are independent, and that Kmax provides a better measure of the convergence than RMTKmax. The dependence of the total energy on RMT is shown to be small if the core states are treated equivalently, and that the XO scheme is able to treat systems with significantly smaller RMT than the standard LAPW method. For converged systems, the calculated lattice parameter, bulk modulus, and magnetic moments are in excellent agreement with the experimental values.
INTERPRETATION OF A SHORT-TERM ANOMALY IN THE GRAVITATIONAL MICROLENSING EVENT MOA-2012-BLG-486
Hwang, K.-H.,Choi, J.-Y.,Bond, I. A.,Sumi, T.,Han, C.,Gaudi, B. S.,Gould, A.,Bozza, V.,Beaulieu, J.-P.,Tsapras, Y.,Abe, F.,Bennett, D. P.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Fukunaga, D.,Ha IOP Publishing 2013 The Astrophysical journal Vol.778 No.1
<P>A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present the analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.</P>
MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS
Choi, J.-Y.,Han, C.,Udalski, A.,Sumi, T.,Gaudi, B. S.,Gould, A.,Bennett, D. P.,Dominik, M.,Beaulieu, J.-P.,Tsapras, Y.,Bozza, V.,Abe, F.,Bond, I. A.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Furu IOP Publishing 2013 The Astrophysical journal Vol.768 No.2
<P>Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M-circle dot and 0.034 M-circle dot, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can robustly form at least down to masses of similar to 0.02 M-circle dot. Future microlensing surveys will measure a mass-selected sample of BD binary systems, which can then be directly compared to similar samples of stellar binaries.</P>
MOA-2011-BLG-293Lb: A TEST OF PURE SURVEY MICROLENSING PLANET DETECTIONS
Yee, J. C.,Shvartzvald, Y.,Gal-Yam, A.,Bond, I. A.,Udalski, A.,Kozłowski, S.,Han, C.,Gould, A.,Skowron, J.,Suzuki, D.,Abe, F.,Bennett, D. P.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Furusawa, K. IOP Publishing 2012 The Astrophysical journal Vol.755 No.2
<P>Because of the development of large-format, wide-field cameras, microlensing surveys are now able to monitor millions of stars with sufficient cadence to detect planets. These new discoveries will span the full range of significance levels including planetary signals too small to be distinguished from the noise. At present, we do not understand where the threshold is for detecting planets. MOA-2011-BLG-293Lb is the first planet to be published from the new surveys, and it also has substantial follow-up observations. This planet is robustly detected in survey+follow-up data (Delta chi(2) similar to 5400). The planet/host mass ratio is q = (5.3 similar to 0.2) x 10(-3). The best-fit projected separation is s = 0.548 +/- 0.005 Einstein radii. However, due to the s <-> s(-1) degeneracy, projected separations of s-1 are only marginally disfavored at Delta chi(2) = 3. A Bayesian estimate of the host mass gives M-L = 0.43(-0.17)(+0.27) M-circle dot, with a sharp upper limit of M-L < 1.2 M-circle dot from upper limits on the lens flux. Hence, the planet mass is m(p) = 2.4(-0.9)(+1.5) M-Jup, and the physical projected separation is either r(perpendicular to) similar or equal to 1.0 AU or r(perpendicular to) similar or equal to 3.4 AU. We show that survey data alone predict this solution and are able to characterize the planet, but the Delta chi(2) is much smaller (Delta chi(2) similar to 500) than with the follow-up data. The Delta chi(2) for the survey data alone is smaller than for any other securely detected planet. This event suggests a means to probe the detection threshold, by analyzing a large sample of events like MOA-2011-BLG-293, which have both follow-up data and high-cadence survey data, to provide a guide for the interpretation of pure survey microlensing data.</P>
Kevin A. Hao,Robert J. Cueto,Christel Gharby,David Freeman,Joseph J. King,Thomas W. Wright,Diana Almader-Douglas,Bradley S. Schoch,Jean-David Werthel 대한견주관절학회 2024 대한견주관절의학회지 Vol.27 No.1
Background: Restoration of external (ER) and internal rotation (IR) after Grammont-style reverse shoulder arthroplasty (RSA) is often unreliable. The purpose of this systematic review was to evaluate the influence of RSA medio-lateral offset and subscapularis repair on axial rotation after RSA. Methods: We conducted a systematic review of studies evaluating axial rotation (ER, IR, or both) after RSA with a defined implant design. Medio-lateral implant classification was adopted from Werthel et al. Meta-analysis was conducted using a random-effects model. Results: Thirty-two studies reporting 2,233 RSAs were included (mean patient age, 72.5 years; follow-up, 43 months; 64% female). The subscapularis was repaired in 91% (n=2,032) of shoulders and did not differ based on global implant lateralization (91% for both, P=0.602). On meta-analysis, globally lateralized implants achieved greater postoperative ER (40° [36°–44°] vs. 27° [22°–32°], P<0.001) and postoperative improvement in ER (20° [15°–26°] vs. 10° [5°–15°], P<0.001). Lateralized implants with subscapularis repair or medialized implants without subscapularis repair had significantly greater postoperative ER and postoperative improvement in ER compared to globally medialized implants with subscapularis repair (P<0.001 for both). Mean postoperative IR was reported in 56% (n=18) of studies and achieved the minimum necessary IR in 51% of lateralized (n=325, 5 cohorts) versus 36% (n=177, 5 cohorts) of medialized implants. Conclusions: Lateralized RSA produces superior axial rotation compared to medialized RSA. Lateralized RSA with subscapularis repair and medialized RSA without subscapularis repair provide greater axial rotation compared to medialized RSA with subscapularis repair. Level of evidence: 2A.
W(110)위에 성장한 Fe 웃층의 전자 및 자기적 성질
홍순철(Soon C. Hong),이재일(Jae Il Lee),A. J. Freeman(A. J. Freeman) 한국자기학회 1991 韓國磁氣學會誌 Vol.1 No.2
The electronic and magnetic structure of Fe overlayers on W(110) is determined by means of the all-electron local spin density full potential linearized augmented plane wave (FLAPW) method with a single slab approach. Charge and spin densities, magnetic moments, contact hyperfine fields, and layer projected density of states (LDOS) are presented. For bilayer Fe coverage, we find magnetic moments to be 2.90 and 2.30 μ_B for the surface and subsurface Fe layers, respectively, corresponding to a 18% enhancement of the total magnetization compared with the calculated bulk value (2.22μ_B);For monolayer coverage the moment is 2.56μ_B which is enhanced by 16% compared to bulk. Unusual changes in the magnetic hyperfine interaction are found in going from a monolayer to a bilayer coverage. Comparison of the results to the theoretical ones of the clean Fe(110) to discuss the hybridization and the negative pressure effects. We discuss our results by comparing them to experimental results.