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Introduction COVID-19 vaccines have been highly effective in reducing morbidity and mortality during the pandemic. While primary series vaccination rates are generally high in Southeast Asian (SEA) countries, various factors have limited the rollout and impact of booster doses. Areas covered We reviewed 79 studies in the International Vaccine Access Center (IVAC) VIEW-hub platform on vaccine effectiveness (VE) after primary immunizations with two-dose schedules. VE data were reported for SARS-CoV-2 infection, COVID-19-related hospitalizations and deaths, and stratified across variants of concern, age, study design and prior SARS-CoV-2 infection for mRNA vaccines (BNT162b2, mRNA-1273, and combinations of both), vector vaccines (AstraZeneca, AZD1222 [ChAdOx1 nCoV-19] ‘Vaxzevria’), and inactivated virus vaccines (CoronaVac). Expert opinion The most-studied COVID-19 vaccines provide consistently high (>90%) protection against serious clinical outcomes like hospitalizations and deaths, regardless of variant. Additionally, this protection appears equivalent for mRNA vaccines and vector vaccines like AZD1222, as supported by our analysis of Asian and relevant international data, and by insights from SEA experts. Given the continued impact of COVID-19 hospitalizations and deaths on health-care systems worldwide, encouraging vaccination strategies that reduce this burden is more relevant than attempting to prevent broader but milder infections with specific variants, including Omicron.

There is ample evidence for magnetic reconnection in the solar system, but it is a nontrivial task to visualize, to determine the proper approaches and frames to study, and in turn to elucidate the physical processes at work in reconnection regions from in-situ measurements of plasma particles and electromagnetic fields. Here an overview is given of a variety of single- and multi-spacecraft data analysis techniques that are key to revealing the context of in-situ observations of magnetic reconnection in space and for detecting and analyzing the diffusion regions where ions and/or electrons are demagnetized. We focus on recent advances in the era of the Magnetospheric Multiscale mission, which has made electron-scale, multi-point measurements of magnetic reconnection in and around Earth's magnetosphere., Comment: submitted to Space Science Reviews (105 pages, incl. 30 figures, 7 tables)

The recently approved Electron-Ion Collider (EIC) will provide a unique new opportunity for searches of charged lepton flavor violation (CLFV) and other new physics scenarios. In contrast to the $e \leftrightarrow μ$ CLFV transition for which very stringent limits exist, there is still a relatively large discovery space for the $e \to τ$ CLFV transition, potentially to be explored by the EIC. With the latest detector design of ECCE (EIC Comprehensive Chromodynamics Experiment) and projected integral luminosity of the EIC, we find the $τ$-leptons created in the DIS process $ep\to τX$ are expected to be identified with high efficiency. A first ECCE simulation study, restricted to the 3-prong $τ$-decay mode and with limited statistics for the Standard Model backgrounds, estimates that the EIC will be able to improve the current exclusion limit on $e\to τ$ CLFV by an order of magnitude., 11 pages, 8 figures, to be submitted to NIM

The ECCE detector has been recommended as the selected reference detector for the future Electron-Ion Collider (EIC). A series of simulation studies have been carried out to validate the physics feasibility of the ECCE detector. In this paper, detailed studies of heavy flavor hadron and jet reconstruction and physics projections with the ECCE detector performance and different magnet options will be presented. The ECCE detector has enabled precise EIC heavy flavor hadron and jet measurements with a broad kinematic coverage. These proposed heavy flavor measurements will help systematically study the hadronization process in vacuum and nuclear medium especially in the underexplored kinematic region., Comment: Open heavy flavor studies with the EIC reference detector design by the ECCE consortium. 11 pages, 11 figures, to be submitted to the Nuclear Instruments and Methods A

Exclusive heavy quarkonium photoproduction is one of the most popular processes in EIC, which has a large cross section and a simple final state. Due to the gluonic nature of the exchange Pomeron, this process can be related to the gluon distributions in the nucleus. The momentum transfer dependence of this process is sensitive to the interaction sites, which provides a powerful tool to probe the spatial distribution of gluons in the nucleus. Recently the problem of the origin of hadron mass has received lots of attention in determining the anomaly contribution $M_{a}$. The trace anomaly is sensitive to the gluon condensate, and exclusive production of quarkonia such as J/$ψ$ and $Υ$ can serve as a sensitive probe to constrain it. In this paper, we present the performance of the ECCE detector for exclusive J/$ψ$ detection and the capability of this process to investigate the above physics opportunities with ECCE., 11 pages, 14 figures, 1 table

BACKGROUND: The cholesteryl ester transfer protein inhibitor evacetrapib substantially raises the high-density lipoprotein (HDL) cholesterol level, reduces the low-density lipoprotein (LDL) cholesterol level, and enhances cellular cholesterol efflux capacity. We sought to determine the effect of evacetrapib on major adverse cardiovascular outcomes in patients with high-risk vascular disease. METHODS: In a multicenter, randomized, double-blind, placebo-controlled phase 3 trial, we enrolled 12,092 patients who had at least one of the following conditions: an acute coronary syndrome within the previous 30 to 365 days, cerebrovascular atherosclerotic disease, peripheral vascular arterial disease, or diabetes mellitus with coronary artery disease. Patients were randomly assigned to receive either evacetrapib at a dose of 130 mg or matching placebo, administered daily, in addition to standard medical therapy. The primary efficacy end point was the first occurrence of any component of the composite of death from cardiovascular causes, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina. RESULTS: At 3 months, a 31.1% decrease in the mean LDL cholesterol level was observed with evacetrapib versus a 6.0% increase with placebo, and a 133.2% increase in the mean HDL cholesterol level was seen with evacetrapib versus a 1.6% increase with placebo. After 1363 of the planned 1670 primary end-point events had occurred, the data and safety monitoring board recommended that the trial be terminated early because of a lack of efficacy. After a median of 26 months of evacetrapib or placebo, a primary end-point event occurred in 12.9% of the patients in the evacetrapib group and in 12.8% of those in the placebo group (hazard ratio, 1.01; 95% confidence interval, 0.91 to 1.11; P=0.91). CONCLUSIONS: Although the cholesteryl ester transfer protein inhibitor evacetrapib had favorable effects on established lipid biomarkers, treatment with evacetrapib did not result in a lower rate of cardiovascular events than placebo among patients with high-risk vascular disease. (Funded by Eli Lilly; ACCELERATE ClinicalTrials.gov number, NCT01687998 .).

Male infertility impacts millions of couples yet, the etiology of primary infertility remains largely unknown. A critical element of successful spermatogenesis is maintenance of genome integrity. Here, we present a genomic study of spermatogenic failure (SPGF). Our initial analysis (n = 176) did not reveal known gene-candidates but identified a potentially significant single-nucleotide variant (SNV) in X-linked germ-cell nuclear antigen (GCNA). Together with a larger follow-up study (n = 2049), 7 likely clinically relevant GCNA variants were identified. GCNA is critical for genome integrity in male meiosis and knockout models exhibit impaired spermatogenesis and infertility. Single-cell RNA-seq and immunohistochemistry confirm human GCNA expression from spermatogonia to elongated spermatids. Five identified SNVs were located in key functional regions, including N-terminal SUMO-interacting motif and C-terminal Spartan-like protease domain. Notably, variant p.Ala115ProfsTer7 results in an early frameshift, while Spartan-like domain missense variants p.Ser659Trp and p.Arg664Cys change conserved residues, likely affecting 3D structure. For variants within GCNA's intrinsically disordered region, we performed computational modeling for consensus motifs. Two SNVs were predicted to impact the structure of these consensus motifs. All identified variants have an extremely low minor allele frequency in the general population and 6 of 7 were not detected in > 5000 biological fathers. Considering evidence from animal models, germ-cell-specific expression, 3D modeling, and computational predictions for SNVs, we propose that identified GCNA variants disrupt structure and function of the respective protein domains, ultimately arresting germ-cell division. To our knowledge, this is the first study implicating GCNA, a key genome integrity factor, in human male infertility.

著者人数: 18名, Accepted: 2018-11-03, 資料番号: SA1180295000

著者人数: 20名, Accepted: 2019-05-28, 資料番号: SA1190061000

We report the discovery of a low-mass-ratio planet (q = 1.3 10-4), i.e., 2.5 times higher than the Neptune/Sun ratio. The planetary system was discovered from the analysis of the KMT-2017-BLG-0165 microlensing event, which has an obvious short-term deviation from the underlying light curve produced by the host of the planet. Although the fit improvement with the microlens parallax effect is relatively low, one component of the parallax vector is strongly constrained from the light curve, making it possible to narrow down the uncertainties of the lens physical properties. A Bayesian analysis yields that the planet has a super-Neptune mass ({M}2={34}-12+15 {M}\oplus ) orbiting a Sun-like star ({M}1={0.76}-0.27+0.34 {M}☉ ) located at 4.5 kpc. The blended light is consistent with these host properties. The projected planet-host separation is {a}\perp ={3.45}-0.95+0.98 {au}, implying that the planet is located outside the snow line of the host, i.e., a sl ~ 2.1 au. KMT-2017-BLG-0165Lb is the sixteenth microlensing planet with mass ratio q < 3 10-4. Using the fifteen of these planets with unambiguous mass-ratio measurements, we apply a likelihood analysis to investigate the form of the mass-ratio function in this regime. If we adopt a broken power law for the form of this function, then the break is at q br ≃ 0.55 10-4, which is much lower than previously estimated. Moreover, the change of the power-law slope, ζ > 3.3, is quite severe. Alternatively, the distribution is also suggestive of a pileup of planets at Neptune-like mass ratios, below which there is a dramatic drop in frequency.

We present the analysis of the microlensing event OGLE-2015-BLG-1670, detected in a high-extinction field very close to the Galactic plane. Due to the dust extinction along the line of sight, this event was too faint to be detected before it reached the peak of magnification. The microlensing light-curve models indicate a high-magnification event with a maximum of A max ≳ 200, very sensitive to planetary deviations. An anomaly in the light curve has been densely observed by the microlensing surveys MOA, KMTNet, and OGLE. From the light-curve modeling, we find a planetary anomaly characterized by a planet-to-host mass ratio, q=≤ft({1.00}-0.16+0.18\right) {10}-4, at the peak recently identified in the mass-ratio function of microlensing planets. Thus, this event is interesting to include in future statistical studies about planet demography. We have explored the possible degeneracies and find two competing planetary models resulting from the s≤ftrightarrow 1/s degeneracy. However, because the projected separation is very close to s = 1, the physical implications for the planet for the two solutions are quite similar, except for the value of s. By combining the light-curve parameters with a Galactic model, we have estimated the planet mass M 2 = {17.9}-8.8+9.6 {M}\oplus and the lens distance {D}{{L}} = {6.7}-1.3+1.0 {kpc}, corresponding to a Neptune-mass planet close to the Galactic bulge. Such events with a low absolute latitude (| b| ≈ 1\buildrel{\circ}\over{.} 1) are subject to both high extinction and more uncertain source distances, two factors that may affect the mass measurements in the provisional Wide Field Infrared Survey Telescope fields. More events are needed to investigate the potential trade-off between the higher lensing rate and the difficulty in measuring masses in these low-latitude fields.

In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based observations combined with the space-based Spitzer observations of this long timescale event enables us to uniquely determine the masses M 1 = 0.40 ± 0.05 M ☉ and M 2 = 0.13 ± 0.01 M ☉ of the individual lens components. Because the lens-source relative parallax and the vector lens-source relative proper motion are unambiguously determined, we can likewise unambiguously predict the astrometric offset between the light centroid of the magnified images (as observed by the Gaia satellite) and the true position of the source. This prediction can be tested when the individual-epoch Gaia astrometric measurements are released.

We report the discovery of the microlensing planet OGLE-2018-BLG-0740Lb. The planet is detected with a very strong signal of ∆χ 2 ∼ 4630, but the interpretation of the signal suffers from two types of degeneracies. One type is caused by the previously known close/wide degeneracy, and the other is caused by an ambiguity between two solutions, in which one solution requires the incorporation of finite- source effects, while the other solution is consistent with a point- source interpretation. Although difficult to be firmly resolved based on only the photometric data, the degeneracy is resolved in strong favor of the point-source solution with the additional external information obtained from astrometric and spectroscopic observations. The small astrometric offset between the source and baseline object supports that the blend is the lens and this interpretation is further secured by the consistency of the spectroscopic distance estimate of the blend with the lensing parameters of the point-source solution. The estimated mass of the host is 1.0 ± 0.1 M ☉ and the mass of the planet is 4.5 ± 0.6 M J (close solution) or 4.8 ± 0.6 M J (wide solution) and the lens is located at a distance of 3.2 ± 0.5 kpc. The bright nature of the lens, with I ∼ 17.1 (V ∼ 18.2), combined with its dominance of the observed flux suggest that radial-velocity (RV) follow- up observations of the lens can be done using high-resolution spectrometers mounted on large telescopes, e.g., Very Large Telescope/ESPRESSO, and this can potentially not only measure the period and eccentricity of the planet but also probe for close-in planets. We estimate that the expected RV amplitude would be ∼ 60\sin i {{m}} {{{s}}}-1.

We report the discovery of a sub-Jupiter-mass planet orbiting beyond the snow line of an M dwarf most likely in the Galactic disk as part of the joint Spitzer and ground-based monitoring of planetary microlensing anomalies toward the Galactic bulge. Most of the microlensing parameters are strongly constrained by the light-curve modeling, and in particular there is a Spitzer-based measurement of the microlens parallax, π E. However, there are no caustic crossings, so the angular Einstein radius has only an upper limit based on the light-curve modeling alone. Additionally, the analysis leads us to identify eight degenerate configurations: the fourfold microlensing parallax degeneracy being doubled by a degeneracy in the caustic structure present at the level of the ground-based solutions. To calculate the physical parameters, and at the same time to break the parallax degeneracy, we make use of a series of arguments: the χ 2 hierarchy, the Rich argument (stating that the small-parallax solution is more likely), and a prior Galactic model. The preferred configuration, favored by a likelihood ratio of at least 4000, is for a host at {D}L={3.73}-0.67+0.66 {kpc} with mass {M}{{L}}={0.30}-0.12+0.15 {M}☉ , orbited by a Saturn-like planet with {M}planet} ={0.43}-0.17+0.21 {M}Jup} at projected separation {a}\perp ={1.70}-0.39+0.38 {au}, about 2.1 times beyond the system snow line. Therefore, it adds to the growing population of sub-Jupiter planets orbiting beyond the snow line of M dwarfs discovered by microlensing. Based on the rules of the real-time protocol for the selection of events to be followed up with Spitzer, this planet will not enter the sample for measuring the Galactic distribution of planets.

We analyze the binary microlensing event MOA-2016-BLG-231, which was observed from the ground and from Spitzer. The lens is composed of very- low-mass brown dwarfs (BDs) with {M}1={21}-5+12 {M}J and {M}2={9}-2+5 {M}J, and it is located in the Galactic disk {D}{{L}}={2.85}-0.50+0.88 {kpc}. This is the fifth binary brown dwarf discovered by microlensing, and the BD binary is moving counter to the orbital motion of disk stars. Constraints on the lens physical properties come from late-time, non- caustic-crossing features of the Spitzer light curve. Thus, MOA-2016-BLG-231 shows how Spitzer plays a crucial role in resolving the nature of BDs in binary BD events with short timescales (‚â≤10 days).

We report a multiplanetary system found from the analysis of microlensing event OGLE-2018-BLG-1011, for which the light curve exhibits a double-bump anomaly around the peak. We find that the anomaly cannot be fully explained by the binary-lens or binary-source interpretations and its description requires the introduction of an additional lens component. The 3L1S (three lens components and a single source) modeling yields three sets of solutions, in which one set of solutions indicates that the lens is a planetary system in a binary, while the other two sets imply that the lens is a multiplanetary system. By investigating the fits of the individual models to the detailed light curve structure, we find that the multiple-planet solution with planet- to-host mass ratios ∼9.5 10−3 and ∼15 10−3 are favored over the other solutions. From the Bayesian analysis, we find that the lens is composed of two planets with masses {1.8}-1.1+3..4 {M}{{J}} and {2.8}-1.7+5.1 {M}{{J}} around a host with a mass {0.18}-0.10+0.33 {M}ȯ and located at a distance {7.1}-1.5+1.1 {kpc}. The estimated distance indicates that the lens is the farthest system among the known multiplanetary systems. The projected planet-host separations are {a}\perp ,2={1.8}-1.5+2.1 {au} ({0.8}-0.6+0.9 {au}) and {a}\perp ,3={0.8}-0.6+0.9 {au}, where the values of a ⊥,2 inside and outside the parenthesis are the separations corresponding to the two degenerate solutions, indicating that both planets are located beyond the snow line of the host, as with the other four multiplanetary systems previously found by microlensing.

We report the discovery of a Spitzer microlensing planet OGLE-2018-BLG- 0596Lb, with preferred planet-host mass ratio q ∼ 2 10−4. The planetary signal, which is characterized by a short (∼1 day) “bump” on the rising side of the lensing light curve, was densely covered by ground-based surveys. We find that the signal can be explained by a bright source that fully envelops the planetary caustic, i.e., a “Hollywood” geometry. Combined with the source proper motion measured from Gaia, the Spitzer satellite parallax measurement makes it possible to precisely constrain the lens physical parameters. The preferred solution, in which the planet perturbs the minor image due to lensing by the host, yields a Uranus-mass planet with a mass of M p = 13.9 ± 1.6 M ⊕ orbiting a mid M-dwarf with a mass of M h = 0.23 ± 0.03 M ☉. There is also a second possible solution that is substantially disfavored but cannot be ruled out, for which the planet perturbs the major image. The latter solution yields M p = 1.2 ± 0.2 M ⊕ and M h = 0.15 ± 0.02 M ☉. By combining the microlensing and Gaia data together with a Galactic model, we find in either case that the lens lies on the near side of the Galactic bulge at a distance D L ∼ 6 ± 1 kpc. Future adaptive optics observations may decisively resolve the major image/minor image degeneracy.

We analyze the gravitational binary-lensing event OGLE-2016-BLG-0156, for which the lensing light curve displays pronounced deviations induced by microlens-parallax effects. The light curve exhibits three distinctive widely separated peaks and we find that the multiple-peak feature provides a very tight constraint on the microlens-parallax effect, enabling us to precisely measure the microlens parallax {π }{{E}}. All the peaks are densely and continuously covered from high-cadence survey observations using globally located telescopes and the analysis of the peaks leads to the precise measurement of the angular Einstein radius {θ }{{E}}. From the combination of the measured {π }{{E}} and {θ }{{E}}, we determine the physical parameters of the lens. It is found that the lens is a binary composed of two M dwarfs with masses M 1 = 0.18 ± 0.01 M ☉ and M 2 = 0.16 ± 0.01 M ☉ located at a distance {D}{{L}}=1.35+/- 0.09 {kpc}. According to the estimated lens mass and distance, the flux from the lens comprises an important fraction, ~25%, of the blended flux. The bright nature of the lens combined with the high relative lens-source motion, μ = 6.94 ± 0.50 mas yr-1, suggests that the lens can be directly observed from future high-resolution follow-up observations.

Planet formation theories predict the existence of free-floating planets that have been ejected from their parent systems. Although they emit little or no light, they can be detected during gravitational microlensing events. Microlensing events caused by rogue planets are characterized by very short timescales tE (typically below two days) and small angular Einstein radii θE (up to several μas). Here we present the discovery and characterization of two ultra- short microlensing events identified in data from the Optical Gravitational Lensing Experiment (OGLE) survey, which may have been caused by free-floating or wide-orbit planets. OGLE-2012-BLG-1323 is one of the shortest events discovered thus far (tE = 0.155 ± 0.005 d, θE = 2.37 ± 0.10μas) and was caused by an Earth-mass object in the Galactic disk or a Neptune-mass planet in the Galactic bulge. OGLE-2017-BLG-0560 (tE = 0.905 ± 0.005 d, θE = 38.7 ± 1.6μas) was caused by a Jupiter-mass planet in the Galactic disk or a brown dwarf in the bulge. We rule out stellar companions up to a distance of 6.0 and 3.9 au, respectively. We suggest that the lensing objects, whether located on very wide orbits or free- floating, may originate from the same physical mechanism. Although the sample of ultrashort microlensing events is small, these detections are consistent with low-mass wide-orbit or unbound planets being more common than stars in the Milky Way.

We analyze the binary gravitational microlensing event OGLE-2017-BLG-1130 (mass ratio q ̃ 0.45), the first published case in which the binary anomaly was detected only by the Spitzer Space Telescope. This event provides strong evidence that some binary signals can be missed by observations from the ground alone but detected by Spitzer. We therefore invert the normal procedure, first finding the lens parameters by fitting the space-based data and then measuring the microlensing parallax using ground-based observations. We also show that the normal four-fold space-based degeneracy in the single-lens case can become a weak eight-fold degeneracy in binary-lens events. Although this degeneracy is resolved in event OGLE-2017-BLG-1130, it might persist in other events.

We report on the discovery and analysis of the short-timescale binary- lens microlensing event, MOA-2015-BLG-337. The lens system could be a planetary system with a very low-mass host, around the brown dwarf (BD )/planetary-mass boundary, or a BD binary. We found two competing models that explain the observed light curves with companion/host mass ratios of q ̃ 0.01 and ̃0.17, respectively. A significant finite source effect in the best-fit planetary model (q ̃ 0.01) reveals a small angular Einstein radius of θ E ≃ 0.03 mas, which favors a low-mass lens. We obtain the posterior probability distribution of the lens properties from a Bayesian analysis. The results for the planetary models strongly depend on a power-law index in planetary-mass regime, α pl, in the assumed mass function. In summary, there are two solutions of the lens system: (1) a BD/planetary-mass boundary object orbited by a super-Neptune (the planetary model with α pl = 0.49) and (2) a BD binary (the binary model). If the planetary models are correct, this system can be one of a new class of planetary system, having a low host mass and also a planetary-mass ratio (q < 0.03) between the companion and its host. The discovery of the event is important for the study of planetary formation in very low-mass objects. In addition, it is important to consider all viable solutions in these kinds of ambiguous events in order for the future comprehensive statistical analyses of planetary/binary microlensing events.

Current microlensing surveys are sensitive to free-floating planets down to Earth-mass objects. All published microlensing events attributed to unbound planets were identified based on their short timescale (below two days), but lacked an angular Einstein radius measurement (and hence lacked a significant constraint on the lens mass). Here, we present the discovery of a Neptune-mass free-floating planet candidate in the ultrashort (t E = 0.320 ± 0.003 days) microlensing event OGLE-2016-BLG-1540. The event exhibited strong finite-source effects, which allowed us to measure its angular Einstein radius of θ E = 9.2 ± 0.5 μas. There remains, however, a degeneracy between the lens mass and distance. The combination of the source proper motion and source-lens relative proper motion measurements favors a Neptune-mass lens located in the Galactic disk. However, we cannot rule out that the lens is a Saturn-mass object belonging to the bulge population. We exclude stellar companions up to ̃15 au.

We analyze the combined Spitzer and ground-based data for OGLE-2017-BLG-1140 and show that the event was generated by a Jupiter- class ({m}p≃ 1.6 {M}{{J}{{u}}{{p}}}) planet orbiting a mid-late M dwarf (M≃ 0.2 {M}☉ ) that lies {D}LS}≃ 1.0 {kpc} in the foreground of the microlensed Galactic-bar source star. The planet-host projected separation is {a}\perp ≃ 1.0 {au}, i.e., well beyond the snow line. By measuring the source proper motion {{\boldsymbol{μ }}}s from ongoing long-term OGLE imaging and combining this with the lens-source relative proper motion {{\boldsymbol{μ }}}rel} derived from the microlensing solution, we show that the lens proper motion {{\boldsymbol{μ }}}l={{\boldsymbol{μ }}}rel}+{{\boldsymbol{μ }}}s is consistent with the lens lying in the Galactic disk, although a bulge lens is not ruled out. We show that while the Spitzer and ground-based data are comparably well fitted by planetary (i.e., binary-lens (2L1S)) and binary-source (1L2S) models, the combination of Spitzer and ground-based data decisively favors the planetary model. This is a new channel to resolve the 2L1S/1L2S degeneracy, which can be difficult to break in some cases.

We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of t E ̃ 7.5 days. The Einstein radius is unusually small, θ E = 0.065 mas, implying that the lens system either has very low mass or lies much closer to the microlensed source than the Sun, or both. A Bayesian analysis yields component masses ({M}host< /SUB>},{M}planet})=({46}-25+79,{0.75}-0.40+1.26) {M}{{J}} and source-lens distance {D}LS}={0.99}-0.54+0.91 {kpc}, implying that this is a brown-dwarf/Jupiter system that probably lies in the Galactic bulge, a location that is also consistent with the relatively low lens-source relative proper motion μ = 3.2 ± 0.5 mas yr-1. The projected companion-host separation is {0.59}-0.11+0.12 {au}, indicating that the planet is placed beyond the snow line of the host, i.e., a sl ̃ 0.12 au. Planet formation scenarios combined with the small companion- host mass ratio q ̃ 0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown-dwarf host.

We report the discovery, via the microlensing method, of a new very low mass binary system. By combining measurements from Earth and from the Spitzer telescope in Earth-trailing orbit, we are able to measure the microlensing parallax of the event, and we find that the lens likely consists of a (12.0 ± 0.6)M J + (15.7 ± 1.5)M J super-Jupiter/brown dwarf pair. The binary is located at a distance of 3.08 ± 0.18 kpc in the Galactic plane, and the components have a projected separation of 0.43 ± 0.03 au. Two alternative solutions with much lower likelihoods are also discussed, an 8M J and 6M J model and a 90M J and 70M J model. If all photometric measurements were independent and Gaussian distributed with known variances, these alternative solutions would be formally disfavored at the 3σ and 5σ levels. We show how the more massive of these models could be tested with future direct imaging.

Mass measurements of gravitational microlenses require one to determine the microlens parallax π E, but precise π E measurement, in many cases, is hampered due to the subtlety of the microlens-parallax signal combined with the difficulty of distinguishing the signal from those induced by other higher-order effects. In this work, we present the analysis of the binary-lens event OGLE-2017-BLG-0329, for which π E is measured with a dramatically improved precision using additional data from space-based Spitzer observations. We find that while the parallax model based on the ground-based data cannot be distinguished from a zero-π E model at the 2σ level, the addition of the Spitzer data enables us to identify two classes of solutions, each composed of a pair of solutions according to the well-known ecliptic degeneracy. It is found that the space-based data reduce the measurement uncertainties of the north and east components of the microlens-parallax vector {{\boldsymbol{π }}}{{E}} by factors ̃18 and ̃4, respectively. With the measured microlens parallax combined with the angular Einstein radius measured from the resolved caustic crossings, we find that the lens is composed of a binary with component masses of either (M 1, M 2) ̃ (1.1, 0.8) M ☉ or ̃(0.4, 0.3) M ☉ according to the two solution classes. The first solution is significantly favored but the second cannot be securely ruled out based on the microlensing data alone. However, the degeneracy can be resolved from adaptive optics observations taken ̃10 years after the event.

We present the analysis of the planetary microlensing event MOA-2016-BLG-319. The event light curve is characterized by a brief (̃3 days) anomaly near the peak produced by minor-image perturbations. From modeling, we find two distinct solutions that describe the observed light curve almost equally as well. From the investigation of the lens- system configurations, we find that the confusion in the lensing solution is caused by the degeneracy between the two solutions resulting from the source passages on different sides of the planetary caustic. These degeneracies can be severe for major-image perturbations, but it is known that they are considerably less severe for minor-image perturbations. From the comparison of the lens-system configuration with those of two previously discovered planetary events, for which similar degeneracies were reported, we find that the degeneracies are caused by the special source trajectories that passed the star-planet axes at approximately right angles. By conducting a Bayesian analysis, it is estimated that the lens is a planetary system in which a giant planet with a mass {M}{{p}}={0.62}-0.33+1.16 {M}{{J}} ({0.65}-0.35+1.21 {M}{{J}}) is orbiting a low-mass M-dwarf host with a mass {M}{{h}}={0.15}-0.08+0.28 {M}☉ . Here the planet masses in and out of the parentheses represent the masses for the individual degenerate solutions. The projected host- planet separations are a ⊥ ̃ 0.95 and ̃1.05 au for the two solutions. The identified degeneracy indicates the need to check similar degeneracies in future analyses of planetary lensing events with minor- image perturbations.

We present microlensing events in the 2015 Korea Microlensing Telescope Network (KMTNet) data and our procedure for identifying these events. In particular, candidates were detected with a novel “completed-event” microlensing event-finder algorithm. The algorithm works by making linear fits to a ({t}0,{t}{eff},{u}0) grid of point-lens microlensing models. This approach is rendered computationally efficient by restricting u 0 to just two values (0 and 1), which we show is quite adequate. The implementation presented here is specifically tailored to the commission-year character of the 2015 data, but the algorithm is quite general and has already been applied to a completely different (non-KMTNet) data set. We outline expected improvements for 2016 and future KMTNet data. The light curves of the 660 “clear microlensing” and 182 “possible microlensing” events that were found in 2015 are presented along with our policy for their public release.

We present an analysis of the binary-lens microlensing event OGLE-2017-BLG-0537. The light curve of the event exhibits two strong caustic-crossing spikes among which the second caustic crossing was resolved by high-cadence surveys. It is found that the lens components with a mass ratio ̃0.5 are separated in projection by ̃ 1.3{θ }{{E}}, where θ E is the angular Einstein radius. Analysis of the caustic-crossing part yields {θ }{{E}}=1.77+/- 0.16 mas and a lens-source relative proper motion of μ = 12.4 ± 1.1 mas yr-1. The measured μ is the third highest value among the events with measured proper motions and is ̃3 times higher than the value of typical Galactic bulge events, making the event a strong candidate for follow-up observations to directly image the lens by separating it from the source. From the angular Einstein radius combined with the microlens parallax, it is estimated that the lens is composed of two main-sequence stars with masses M 1 ̃ 0.4 M ☉ and M 2 ̃ 0.2 M ☉ located at a distance of D L ̃ 1.2 kpc. However, the physical lens parameters are not very secure due to the weak microlens-parallax signal, thus we cross-check the parameters by conducting a Bayesian analysis based on the measured Einstein radius and event timescale, combined with the blending constraint. From this, we find that the physical parameters estimated from the Bayesian analysis are consistent with those based on the measured microlens parallax. Resolving the lens from the source can be done in about 5 years from high-resolution follow-up observations and this will provide a rare opportunity to test and refine the microlensing model.

We present the analysis of a binary microlensing event, KMT-2016-BLG-2052, for which the lensing-induced brightening of the source star lasted for two seasons. We determine the lens mass from the combined measurements of the microlens parallax, π E, and angular Einstein radius, θ E. The measured mass indicates that the lens is a binary composed of M dwarfs with masses of M 1 ̃ 0.34 M ☉ and M 2 ̃ 0.17 M ☉. The measured relative lens-source proper motion of μ ̃ 3.9 mas yr-1 is smaller than ̃5 mas yr-1 of typical Galactic lensing events, while the estimated angular Einstein radius of θ E ̃ 1.2 mas is substantially greater than the typical value of ̃0.5 mas. Therefore, it turns out that the long timescale of the event is caused by the combination of the slow μ and large θ E rather than the heavy mass of the lens. From the simulation of Galactic lensing events with very long timescales (t E ≳ 100 days), we find that the probabilities that long timescale events are produced by lenses with masses ≥1.0 M ☉ and ≥3.0 M ☉ are ̃19% and 2.6%, respectively, indicating that events produced by heavy lenses comprise a minor fraction of long timescale events. The results indicate that it is essential to determine lens masses by measuring both π E and θ E in order to firmly identify heavy stellar remnants, such as neutron stars and black holes.

We present microlensing planet OGLE-2017-BLG-0173Lb, with planet-host mass ratio of either q≃ 2.5× {10}-5 or q≃ 6.5× {10}-5, the lowest or among the lowest ever detected. The planetary perturbation is strongly detected, ∆χ 2 ̃ 10000, because it arises from a bright (therefore, large) source passing over and enveloping the planetary caustic: a so-called “Hollywood” event. The factor ̃2.5 offset in q arises because of a previously unrecognized discrete degeneracy between Hollywood events in which the caustic is fully enveloped and those in which only one flank is enveloped, which we dub “Cannae” and “von Schlieffen,” respectively. This degeneracy is “accidental” in that it arises from gaps in the data. Nevertheless, the fact that it appears in a ∆χ 2 = 10000 planetary anomaly is striking. We present a simple formalism to estimate the sensitivity of other Hollywood events to planets and show that they can lead to detections close to, but perhaps not quite reaching, the Earth/Sun mass ratio of 3× {10}-6. This formalism also enables an analytic understanding of the factor ̃2.5 offset in q between the Cannae and von Schlieffen solutions. The Bayesian estimates for the host mass, system distance, and planet-host projected separation are M={0.39}-0.24+0.40 {M}☉ , {D}L={4.8}-1.8+1.5 {kpc}, and {a}\perp =3.8+/- 1.6 {au}, respectively. The two estimates of the planet mass are {m}p={3.3}-2.1+3.8 {M}\oplus and {m}p={8}-6+11 {M}\oplus . The measured lens-source relative proper motion μ =6 {mas} {yr}}-1 will permit imaging of the lens in about 15 years or at first light on adaptive-optics imagers on next-generation telescopes. These will allow one to measure the host mass but probably will not be able to resolve the planet-host mass-ratio degeneracy.

We present Korea Microlensing Telescope Network (KMTNet) light curves for microlensing-event candidates in the Kepler K2 C9 field having peaks within three effective timescales of the Kepler observations. These include 181 “clear microlensing” and 84 “possible microlensing” events found by the KMTNet event finder, plus 56 other events found by OGLE and/or MOA that were not found by KMTNet. All data for the first two classes are immediately available for public use without restriction.

We report the discovery of a planetary system in which a super-Earth orbits a late M-dwarf host. The planetary system was found from the analysis of the microlensing event OGLE-2017-BLG-0482, wherein the planet signal appears as a short-term anomaly to the smooth lensing light curve produced by the host. Despite its weak signal and short duration, the planetary signal was firmly detected from the dense and continuous coverage by three microlensing surveys. We find a planet/host mass ratio of q ̃ 1.4 × 10-4. We measure the microlens parallax {π }{{E}} from the long-term deviation in the observed lensing light curve, but the angular Einstein radius {θ }{{E}} cannot be measured because the source trajectory did not cross the planet-induced caustic. Using the measured event timescale and the microlens parallax, we find that the masses of the planet and the host are {M}{{p}}={9.0}-4.5+9.0 {M}\oplus and {M}host}={0.20}-0.10+0.20 {M}☉ , respectively, and the projected separation between them is {a}\perp ={1.8}-0.7+0.6 au. The estimated distance to the lens is {D}{{L}}={5.8}-2.1+1.8 kpc. The discovery of the planetary system demonstrates that microlensing provides an important method to detect low-mass planets orbiting low- mass stars.

We present Korea Microlensing Telescope Network (KMTNet) light curves for microlensing-event candidates for the 2016 season, which covers an area of 97 sq.deg observed at cadences ranging from Gamma=0.2/hr to Gamma=8/hr from three southern sites in Chile, South Africa, and Australia. These 2163 light curves are comprised of 1856 "clear microlensing" and 307 "possible microlensing" events (including 265 previously released from the K2 C9 field). The data policy is very similar to the one governing the 2015 release. The changes relative to 2015 in the algorithms to find and vet microlensing events are comprehensively described., Comment: 14 pages, 2 Figures, submitted to AAS Journals

We show that dense OGLE and KMTNet I-band survey data require four bodies (sources plus lenses) to explain the microlensing light curve of OGLE-2015-BLG-1459. However, these can equally well consist of three lenses and one source (3L1S), two lenses and two sources (2L2S), or one lens and three sources (1L3S). In the 3L1S and 2L2S interpretations, the host is a brown dwarf and the dominant companion is a Neptune-class planet, with the third body (in the 3L1S case) being a Mars-class object that could have been a moon of the planet. In the 1L3S solution, the light curve anomalies are explained by a tight (five stellar radii) low- luminosity binary source that is offset from the principal source of the event by ̃ 0.17 {au}. These degeneracies are resolved in favor of the 1L3S solution by color effects derived from comparison to MOA data, which are taken in a slightly different (R/I) passband. To enable current and future (WFIRST) surveys to routinely characterize exo-moons and distinguish among such exotic systems requires an observing strategy that includes both a cadence faster than 9 minute-1 and observations in a second band on a similar timescale.

We report the discovery of a cold Super-Earth planet (m_p=4.4 +/- 0.5 M_Earth) orbiting a low-mass (M=0.23 +/- 0.03 M_Sun) M dwarf at projected separation a_perp = 1.18 +/- 0.10 AU, i.e., about 1.9 times the snow line. The system is quite nearby for a microlensing planet, D_Lens = 0.86 +/- 0.09 kpc. Indeed, it was the large lens-source relative parallax pi_rel=1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax" that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q < 1 * 10^-4. We apply a new planet-detection sensitivity method, which is a variant of "V/V_max", to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/d(ln q) ~ q^p, with p = 1.05 (+0.78,-0.68), which confirms the "turnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n = -0.93 +/- 0.13 at higher mass ratios q >~ 2 * 10^-4. We combine our result with that of Suzuki et al. to obtain p = 0.73 (+0.42,-0.34)., 53 pages, 16 figures

Microlensing is a powerful and unique technique to probe isolated objects in the Galaxy. To study the characteristics of these interesting objects based on the microlensing method, measurement of the microlens parallax is required to determine the properties of the lens. Of the various methods to measure microlens parallax, the most routine way is to make simultaneous ground- and space-based observations, i.e., by measuring the space-based microlens parallax. However, space-based campaigns usually require “expensive” resources. Gould & Yee (2012) proposed an idea called the “cheap space-based microlens parallax” that can measure the lens-parallax using only two or three space-based observations of high-magnification events (as seen from Earth). This cost-effective observation strategy to measure microlens parallaxes could be used by space-borne telescopes to build a complete sample for studying isolated objects. This would enable a direct measurement of the mass function including both extremely low-mass objects and high-mass stellar remnants. However, to adopt this idea requires a test to check how it would work in actual situations. Thus, we present the first practical test of this idea using the high-magnification microlensing event OGLE-2016-BLG-1045, for which a subset of Spitzer observations fortuitously duplicates the prescription of Gould & Yee (2012). From the test, we confirm that the measurement of the lens-parallax adopting this idea has sufficient accuracy to determine the physical properties of the isolated lens.

We present microlensing events in the 2015 Korea Microlensing Telescope Network (KMTNet) data and our procedure for identifying these events. In particular, candidates were detected with a novel "completed event" microlensing event-finder algorithm. The algorithm works by making linear fits to a (t0,teff,u0) grid of point-lens microlensing models. This approach is rendered computationally efficient by restricting u0 to just two values (0 and 1), which we show is quite adequate. The implementation presented here is specifically tailored to the commission-year character of the 2015 data, but the algorithm is quite general and has already been applied to a completely different (non-KMTNet) data set. We outline expected improvements for 2016 and future KMTNet data. The light curves of the 660 "clear microlensing" and 182 "possible microlensing" events that were found in 2015 are presented along with our policy for their public release., Comment: AJ, in press, 39 pages, 12 figures. Lightcurves at http://kmtnet.kasi.re.kr/~ulens/event/2015/ . See Section 5 for data policy

We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations from Spitzer and the ground yield measurements of the microlensing parallax vector $��_{\rm E}$, from which compact constraints on the microlens properties are derived, including $\lesssim$25\% uncertainties on the lens mass and distance. With the current sample, we demonstrate that the majority of microlenses are indeed in the mass range of M dwarfs. The planet sensitivities of all 41 events in the sample are calculated, from which we provide constraints on the planet distribution function. In particular, assuming a planet distribution function that is uniform in $\log{q}$, where $q$ is the planet-to-star mass ratio, we find a $95\%$ upper limit on the fraction of stars that host typical microlensing planets of 49\%, which is consistent with previous studies. Based on this planet-free sample, we develop the methodology to statistically study the Galactic distribution of planets using microlensing parallax measurements. Under the assumption that the planet distributions are the same in the bulge as in the disk, we predict that $\sim$1/3 of all planet detections from the microlensing campaigns with Spitzer should be in the bulge. This prediction will be tested with a much larger sample, and deviations from it can be used to constrain the abundance of planets in the bulge relative to the disk., published on Astronomical Journal

Data from the NASA Magnetospheric Multiscale (MMS) mission are used to investigate asymmetric magnetic reconnection at the dayside boundary between the Earth's magnetosphere and the solar wind (the magnetopause). High-resolution measurements of plasmas, electric and magnetic fields, and waves are used to identify highly localized (~15 electron Debye lengths) standing wave structures with large electric-field amplitudes (up to 100 mV/m). These wave structures are associated with spatially oscillatory dissipation, which appears as alternatingly positive and negative values of J dot E (dissipation). For small guide magnetic fields the wave structures occur in the electron stagnation region at the magnetosphere edge of the EDR. For larger guide fields the structures also occur near the reconnection x-line. This difference is explained in terms of channels for the out-of-plane current (agyrotropic electrons at the stagnation point and guide-field-aligned electrons at the x-line).

We report the result of the analysis of the light curve of the microlensing event MOA-2009-BLG-016. The light curve is characterized by a short-duration anomaly near the peak and an overall asymmetry. We find that the peak anomaly is due to a binary companion to the primary lens and the asymmetry of the light curve is explained by the parallax effect caused by the acceleration of the observer over the course of the event due to the orbital motion of the Earth around the Sun. In addition, we detect evidence for the effect of the finite size of the source near the peak of the event, which allows us to measure the angular Einstein radius of the lens system. The Einstein radius combined with the microlens parallax allows us to determine the total mass of the lens and the distance to the lens. We identify three distinct classes of degenerate solutions for the binary lens parameters, where two are manifestations of the previously identified degeneracies of close/wide binaries and positive/negative impact parameters, while the third class is caused by the symmetric cycloid shape of the caustic. We find that, for the best-fit solution, the estimated mass of the lower-mass component of the binary is (0.04 +- 0.01) M_sun, implying a brown-dwarf companion. However, there exists a solution that is worse only by \Delta\chi^2 ~ 3 for which the mass of the secondary is above the hydrogen-burning limit. Unfortunately, resolving these two degenerate solutions will be difficult as the relative lens-source proper motions for both are similar and small (~ 1 mas/yr) and thus the lens will remain blended with the source for the next several decades., Comment: 7 pages, 2 tables, and 5 figures

For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing datasets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (A_{max} \sim 3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (\sim 3M_\oplus ) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favour the planetary interpretation when systematic errors are taken into account., Comment: accepted ApJ 2015

The microlens parallax is a crucial observable for conclusively identifying the nature of lens systems in microlensing events containing or composed of faint (even dark) astronomical objects such as planets, neutron stars, brown dwarfs, and black holes. With the commencement of a new era of microlensing in collaboration with space-based observations, the microlens parallax can be routinely measured. In addition, space-based observations can provide opportunities to verify the microlens parallax measured from ground-only observations and to find a unique solution of the lensing lightcurve analysis. However, since most space-based observations cannot cover the full lightcurves of lensing events, it is also necessary to verify the reliability of the information extracted from fragmentary space-based lightcurves. We conduct a test based on the microlensing event OGLE-2016-BLG-0168 created by a binary lens system consisting of almost equal mass M-dwarf stars to demonstrate that it is possible to verify the microlens parallax and to resolve degeneracies by using the space-based lightcurve even though the observations are fragmentary. Since space-based observatories will frequently produce fragmentary lightcurves due to their short observing windows, the methodology of this test will be useful for next-generation microlensing experiments that combine space-based and ground-based collaboration., 9 pages, 5 figures, 3 tables, submitted in ApJ

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