362 research outputs found
Pigmented Villonodular Synovitis of the Elbow: A Case Report and Sonographic Findings
Pigmented villonodular synovitis (PVNS) is a disease rarely found in the elbow, and there is limited literature describing its ultrasonographic morphology. We report a case of elbow PVNS, showing the sonographic features of a hyperechoic, heterogenous, irregularly-shaped mass. Compared to knee joint PVNS, elbow joint PVNS has less joint effusion. This is also the first article to demonstrate the increased blood perfusion of PVNS with power-mode Doppler imaging
Endogenous Bacterial Endophthalmitis Caused by Iliopsoas Abscess
A 79-year-old woman presented to our hospital with a 10-day history of gradually worsening binocular vision and severe backache. Further investigations revealed poor bilateral best-corrected visual acuities (BCVA), bilateral vitreous opacities, gray-white lesions scattered throughout the retina, and a left iliopsoas abscess on CT that later grew out methicillin-sensitive S. aureus. The abscess was drained and intravenous antibiotics were initiated, but the left eye additionally required intravitreal vancomycin. BCVA for both eyes normalized within 1 year. Intramuscular abscess should be considered as a possible primary lesion in cases of endogenous bacterial endophthalmitis
Brown dwarf companions in binaries detected from the 2021 season high-cadence microlensing surveys
As a part of the project aiming to build a homogeneous sample of binary-lens
(2L1S) events containing brown-dwarf (BD) companions, we investigate the 2021
season microlensing data collected by the Korea Microlensing Telescope Network
(KMTNet) survey. For this purpose, we first identify 2L1S events by conducting
systematic analyses of anomalous lensing events. We then select candidate
BD-companion events by applying the criterion that the mass ratio between the
lens components is less than . From this procedure, we find
four binary-lens events including KMT-2021-BLG-0588, KMT-2021-BLG-1110,
KMT-2021-BLG-1643, and KMT-2021-BLG-1770, for which the estimated mass ratios
are , 0.07, 0.08, and 0.15, respectively. The event
KMT-2021-BLG-1770 is selected as a candidate despite the fact that the mass
ratio is slightly greater than because the lens mass expected from
the measured short time scale of the event, ~days, is small.
From the Bayesian analyses, we estimate that the primary and companion masses
are for KMT-2021-BLG-0588L, for KMT-2021-BLG-1110L, for KMT-2021-BLG-1643L, and for KMT-2021-BLG-1770L. It is estimated that the
probabilities of the lens companions being in the BD mass range are 82\%, 85\%,
91\%, and 59\% for the individual events. For confirming the BD nature of the
lens companions found in this and previous works by directly imaging the lenses
from future high-resolution adaptive-optics (AO) followup observations, we
provide the lens-source separations expected in 2030, which is an approximate
year of the first AO light on 30~m class telescopes.Comment: 11 pages, 10 tables, 8 figure
KMT-2021-BLG-1150Lb: Microlensing planet detected through a densely covered planetary-caustic signal
Recently, there have been reports of various types of degeneracies in the
interpretation of planetary signals induced by planetary caustics. In this
work, we check whether such degeneracies persist in the case of well-covered
signals by analyzing the lensing event KMT-2021-BLG-1150, for which the light
curve exhibits a densely and continuously covered short-term anomaly. In order
to identify degenerate solutions, we thoroughly investigate the parameter space
by conducting dense grid searches for the lensing parameters. We then check the
severity of the degeneracy among the identified solutions. We identify a pair
of planetary solutions resulting from the well-known inner-outer degeneracy,
and find that interpreting the anomaly is not subject to any degeneracy other
than the inner-outer degeneracy. The measured parameters of the planet
separation (normalized to the Einstein radius) and mass ratio between the lens
components are for the inner
solution and for the outer
solution. According to a Bayesian estimation, the lens is a planetary system
consisting of a planet with a mass
and its host with a mass lying toward
the Galactic center at a distance ~kpc. By
conducting analyses using mock data sets prepared to mimic those obtained with
data gaps and under various observational cadences, it is found that gaps in
data can result in various degenerate solutions, while the observational
cadence does not pose a serious degeneracy problem as long as the anomaly
feature can be delineated.Comment: 9 pages, 8 figure
KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed by source binarity
We investigate the previous microlensing data collected by the KMTNet survey
in search of anomalous events for which no precise interpretations of the
anomalies have been suggested. From this investigation, we find that the
anomaly in the lensing light curve of the event KMT-2021-BLG-1547 is
approximately described by a binary-lens (2L1S) model with a lens possessing a
giant planet, but the model leaves unexplained residuals. We investigate the
origin of the residuals by testing more sophisticated models that include
either an extra lens component (3L1S model) or an extra source star (2L2S
model) to the 2L1S configuration of the lens system. From these analyses, we
find that the residuals from the 2L1S model originate from the existence of a
faint companion to the source. The 2L2S solution substantially reduces the
residuals and improves the model fit by with respect to the
2L1S solution. The 3L1S solution also improves the fit, but its fit is worse
than that of the 2L2S solution by . According to the 2L2S
solution, the lens of the event is a planetary system with planet and host
masses lying at a distance \D_{\rm L}
=5.07^{+0.98}_{-1.50}~kpc, and the source is a binary composed of a subgiant
primary of a late G or an early K spectral type and a main-sequence companion
of a K spectral type. The event demonstrates the need of sophisticated modeling
for unexplained anomalies for the construction of a complete microlensing
planet sample.Comment: 9 pages, 4 tables, 7 figure
KMT-2022-BLG-0440Lb: A New Microlensing Planet with the Central-Resonant Caustic Degeneracy Broken
We present the observations and analysis of a high-magnification microlensing
planetary event, KMT-2022-BLG-0440, for which the weak and short-lived
planetary signal was covered by both the KMTNet survey and follow-up
observations. The binary-lens models with a central caustic provide the best
fits, with a planet/host mass ratio, -- at
. The binary-lens models with a resonant caustic and a brown-dwarf
mass ratio are both excluded by . The binary-source model
can fit the anomaly well but is rejected by the ``color argument'' on the
second source. From Bayesian analyses, it is estimated that the host star is
likely a K or M dwarf located in the Galactic disk, the planet probably has a
Neptune-mass, and the projected planet-host separation is
or au, subject to the close/wide degeneracy. This is the
third planet from a high-magnification planetary signal (). Together with another such planet, KMT-2021-BLG-0171Lb, the
ongoing follow-up program for the KMTNet high-magnification events has
demonstrated its ability in detecting high-magnification planetary signals for
planets, which are challenging for the current microlensing
surveys.Comment: MNRAS accepte
Systematic KMTNet Planetary Anomaly Search. IX. Complete Sample of 2016 Prime-Field Planets
As a part of the ``Systematic KMTNet Planetary Anomaly Search" series, we
report five new planets (namely, OGLE-2016-BLG-1635Lb, MOA-2016-BLG-532Lb,
KMT-2016-BLG-0625Lb, OGLE-2016-BLG-1850Lb, and KMT-2016-BLG-1751Lb) and one
planet candidate (KMT-2016-BLG-1855), which were found by searching
KMTNet prime fields. These planets show a wide range of masses from
Earth--class to Super--Jupiter--class, and are located in both the disk and the
bulge. The ultimate goal of this series is to build a complete planet sample.
Because our work provides a complementary sample to other planet detection
methods, which have different detection sensitivities, our complete sample will
help us to obtain a better understanding of planet demographics in our Galaxy.Comment: 38 pages, 17 figures, 12 Tables, submitted to the AAS journa
KMT-2023-BLG-1431Lb: A New Microlensing Planet from a Subtle Signature
The current studies of microlensing planets are limited by small number
statistics. Follow-up observations of high-magnification microlensing events
can efficiently form a statistical planetary sample. Since 2020, the Korea
Microlensing Telescope Network (KMTNet) and the Las Cumbres Observatory (LCO)
global network have been conducting a follow-up program for high-magnification
KMTNet events. Here, we report the detection and analysis of a microlensing
planetary event, KMT-2023-BLG-1431, for which the subtle (0.05 magnitude) and
short-lived (5 hours) planetary signature was characterized by the follow-up
from KMTNet and LCO. A binary-lens single-source (2L1S) analysis reveals a
planet/host mass ratio of , and the
single-lens binary-source (1L2S) model is excluded by . A
Bayesian analysis using a Galactic model yields estimates of the host star mass
of , the planetary mass of , and the lens distance of kpc. The projected planet-host separation of au or , subject to the
close/wide degeneracy. We also find that without the follow-up data, the
survey-only data cannot break the degeneracy of central/resonant caustics and
the degeneracy of 2L1S/1L2S models, showing the importance of follow-up
observations for current microlensing surveys.Comment: PASP submitted. arXiv admin note: text overlap with arXiv:2301.0677
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