167 research outputs found
KMT-2018-BLG-1292: A Super-Jovian Microlens Planet in the Galactic Plane
We report the discovery of KMT-2018-BLG-1292Lb, a super-Jovian planet orbiting an F or G dwarf , which lies physically within {\cal O}(10\,\pc) of the
Galactic plane. The source star is a heavily extincted luminous
giant that has the lowest Galactic latitude, , of any planetary
microlensing event. The relatively blue blended light is almost certainly
either the host or its binary companion, with the first explanation being
substantially more likely. This blend dominates the light at band and
completely dominates at and bands. Hence, the lens system can be probed
by follow-up observations immediately, i.e., long before the lens system and
the source separate due to their relative proper motion. The system is well
characterized despite the low cadence -- of
observations and short viewing windows near the end of the bulge season. This
suggests that optical microlensing planet searches can be extended to the
Galactic plane at relatively modest cost.Comment: 35 pages, 3 Tables, 8 figure
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Parental Monitoring of Childrenâs Media Consumption: The Long-term Influences on Body Mass Index in Children
IMPORTANCE: Although childrenâs media consumption has been one of the most robust risk factors for childhood obesity, effects of specific parenting influences, such as parental media monitoring, have not been effectively investigated.
OBJECTIVES: This study examined the potential influences of maternal and paternal monitoring of child media exposure and childrenâs general activities on childrenâs BMI in middle childhood.
DESIGN: A longitudinal study, taken from a subsample of the Three Generational Study, with assessments at childrenâs ages of 5, 7, and/or 9 years collected from 1998-2012.
SETTING: The Three Generational Study, a predominantly Caucasian, Pacific-Northwest U.S. community sample (overall participation rate 90%).
PARTICIPANTS: Analyses included 112 mothers, 103 fathers and their 213 children (55% girls) at ages 5, 7, and/or 9 years. Participation rates ranged from 67% to 72% of all eligible Three Generational Study children across the three assessments.
MAIN EXPOSURES: Parents reported on their general monitoring of their children (whereabouts and activities), specific monitoring of child media exposure, childrenâs participation in sports and recreational activities, childrenâs media time (hours/week), annual income, and education level. Parental BMI was recorded.
MAIN OUTCOME MEASURE: Predictions to level and change in child BMI z scores were tested.
RESULTS: Linear mixed-effects modeling indicated that more maternal, but not paternal, monitoring of child media exposure predicted lower child BMI z scores at age 7 years (95% CI, -.39 â -.07) and less steeply increasing child BMI z scores from ages 5-9 years (95% CI, -.11 â -.01). These effects held when controlling for more general parental monitoring, and parent BMI, income and education. Results supported that the significant negative effect of maternal media monitoring on childrenâs BMI z scores at age 7 years was marginally accounted for by the effect of child media time. The maternal media monitoring effect on childrenâs BMI z score slopes remained significant once adjusting for childrenâs media time, and sports and recreational activity.
CONCLUSIONS: This study suggests that parental behaviors related to childrenâs media consumption may have long-term impacts on childrenâs BMI in middle childhood. The results underscore the importance of targeting parental media monitoring in efforts to prevent childhood obesity
Spectroscopic Mass and Host-star Metallicity Measurements for Newly Discovered Microlensing Planet OGLE-2018-BLG-0740Lb
We report the discovery of the microlensing planet OGLE-2018-BLG-0740Lb. The
planet is detected with a very strong signal of , 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 to
incorporate 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 and the mass
of the planet is (close solution) or (wide solution) and the lens is located at a distance of ~kpc.
The bright nature of the lens, with (), 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., VLT/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 .Comment: 12 pages, 11 figures, 4 table
OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event
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 {\it Spitzer} observations of this
long time-scale event enables us to uniquely determine the masses and 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 {\it Gaia} satellite) and the true position of the
source. This prediction can be tested when the individual-epoch {\it Gaia}
astrometric measurements are released.Comment: 10 pages, 10 figures, 4 table
Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii
Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales t_E because short-timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales (t_E âČ 6 days) but also with very small angular Einstein radii (Ξ_E âČ 0.05 mas) among the events that have been found in the 2016â2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined t_E and Ξ_E constraint, it is estimated that the lens masses of the individual events are
0.051^(+0.100)_(â0.027) Mâ, 0.044^(+0.090)_(â0.023) Mâ, and 0.046^(+0.067)_(â0.023) Mâ/0.038^(+0.056)_(â0.019) Mâ and the probability of the lens mass smaller than the lower limit of stars is ~80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations
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