A5009143104- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Optical Systems and Laser Technology
- Gamma-ray bursts and supernovae
- Impact of Light on Environment and Health
- Advanced Optical Sensing Technologies
- Geophysics and Gravity Measurements
- Mechanics and Biomechanics Studies
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- Advanced optical system design
- Advanced Image Processing Techniques
- History and Developments in Astronomy
- Fiscal Policy and Economic Growth
- Fiscal Policies and Political Economy
- Historical and Architectural Studies
University of California, Berkeley
2021-2024
Goddard Space Flight Center
2015-2024
University of Maryland, College Park
2024
Berkeley College
2023
Catholic University of America
2020-2021
University of America
2020-2021
Université Paris-Saclay
2021
Abstract We present the analysis of five black hole candidates identified from gravitational microlensing surveys. Hubble Space Telescope astrometric data and densely sampled light curves ground-based surveys are fit with a single-source, single-lens model in order to measure mass luminosity each lens determine if it is hole. One targets (OGLE-2011-BLG-0462/MOA-2011-BLG-191 or OB110462 for short) shows significant >1 mas coherent shift, little no flux, has an inferred 1.6–4.4 M ⊙ . This...
We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm relative proper motion prediction due to light curve signal observed this event. This (and companion Keck result) provide first confirmation a signal, deviation was only 2%. The follow-up determine flux host star in multiple passbands remove model ambiguity caused by sparse sampling part curve. leads precise...
Abstract We present adaptive optics imaging from the NIRC2 instrument on Keck II telescope that resolves exoplanet host (and lens) star as it separates brighter source star. These observations yield K -band brightness of lens and planetary star, well lens-source relative proper motion, <?CDATA ${{\boldsymbol{\mu }}}_{\mathrm{rel},{\rm{H}}}$?> , in heliocentric reference frame. The measurement allows for determination microlensing parallax vector, ${{\boldsymbol{\pi }}}_{E}$?> which had only...
Abstract We present an analysis of adaptive optics images from the Keck I telescope microlensing event MOA-2011-BLG-262. The original discovery paper by Bennett et al. reports two possibilities for lens system: a nearby gas giant with exomoon companion or very low-mass star planetary in Galactic bulge. ∼10 yr baseline between and follow-up observations allows us to detect faint candidate host (star) at K = 22.3 mag confirm distant system interpretation. combination brightness light curve...
The United Kingdom Infrared Telescope (UKIRT) microlensing survey was conducted over four years, from 2016 to 2019, with the goal of serving as a precursor future near-infrared surveys Shvartzvald2017 . Focusing on stars in Galactic center and utilizing passbands, identified approximately one thousand events, 27 which displayed anomalies their light curves Wen2023 This paper presents an analysis these anomalous aiming uncover underlying causes observed anomalies. events were analyzed under...
Abstract We revisit the planetary microlensing event OGLE-2013-BLG-0132/MOA-2013-BLG-148 using Keck adaptive optics imaging in 2013 with NIRC2 and 2020, 7.4 yr after event, OSIRIS. The 2020 observations yield a source lens separation of 56.91 ± 0.29 mas, which provides us precise measurement heliocentric proper motion μ rel,hel = 7.695 0.039 mas −1 . measured magnitude K band as 18.69 0.04. Using these constraints, we refit light curve undertake full reanalysis parameters including parallax...
Abstract We present high angular resolution imaging that detects the MOA-2008-BLG-379L exoplanet host star using Keck adaptive optics and Hubble Space Telescope. These observations reveal planet masses of M = 0.434 ± 0.065 ⊙ m p 2.44 0.49 Jupiter . They are located at a distance D L 3.44 0.53 kpc, with projected separation 2.70 0.42 au. results contribute to our determination for Suzuki et al. statistical sample, which will determine dependence occurrence rate on mass stars. also detailed...
Abstract We present an analysis of high-angular-resolution images the microlensing target MOA-2007-BLG-192 using Keck adaptive optics and Hubble Space Telescope. The planetary host star is robustly detected as it separates from background source in nearly all data. amplitude direction lens–source separation allows us to break a degeneracy related parallax radius crossing time. Thus, we are able reduce number possible binary-lens solutions by factor ∼2, demonstrating power follow-up imaging...
We present an adaptive optics (AO) analysis of images from the Keck-II telescope NIRC2 instrument planetary microlensing event MOA-2009-BLG-319. The $\sim$10 year baseline between and Keck observations allows host star to be detected at a separation $66.5\pm 1.7\,$mas source star, consistent with light curve model prediction. combination brightness parameters yield planet masses M_host = 0.514 $\pm$ 0.063M_Sun m_p 66.0 8.1M_Earth distance $D_L 7.0 \pm 0.7\,$kpc. star-planet projected is...
Abstract We present Keck/NIRC2 adaptive optics imaging of planetary microlensing event MOA-2007-BLG-400 that resolves the lens star system from source. find MOA-2007-BLG-400L consists a 1.71 ± 0.27 M Jup planet orbiting 0.69 0.04 ⊙ K-dwarf host at distance 6.89 0.77 kpc Sun. So, this probably resides in Galactic bulge. The planet–host projected separation is only weakly constrained due to close-wide light-curve degeneracy; 2 σ ranges are 0.6–1.0 au and 4.7–7.7 for close wide solutions,...
We present an analysis of six independent on-sky datasets taken with the Keck-II/NIRC2 instrument. Using off-axis point spread function (PSF) reconstruction software AIROPA, we extract stellar astrometry, photometry, and other fitting metrics to characterize performance this package. test effectiveness AIROPA reconstruct PSF across field view in varying atmospheric conditions, number location reference stars, crowding, telescope position angle (PA). compare astrometric precision residuals...
Abstract We report new results for the gravitational microlensing target OGLE-2011-BLG-0950 from adaptive optics images using Keck Observatory. The original analysis by Choi et al. and reanalysis Suzuki degenerate solutions between planetary stellar binary lens systems. This particular case is most important type of degeneracy exoplanet demographics because distinction a mass or companion has direct consequences statistics. 8 10 yr baselines allow us to directly measure relative proper...
We present an analysis of high angular resolution images the microlensing target MOA-2007-BLG-192 using Keck adaptive optics and Hubble Space Telescope. The planetary host star is robustly detected as it separates from background source in nearly all data. amplitude direction lens-source separation allows us to break a degeneracy related parallax radius crossing time. Thus, we are able reduce number possible solutions by factor ${\sim}2$, demonstrating power follow-up imaging for events with...
Abstract We measure the dependence of planet frequency on host star mass, M L , and distance from Galactic center, R using a sample planets discovered by gravitational microlensing. compare two-dimensional distribution lens-source proper motion, μ rel Einstein radius crossing time, t E measured for 22 planetary events Suzuki et al. with expected model. Assuming that planet-hosting probability is proportional to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...
Abstract This supplement provides supporting material for Lam et al. We briefly summarize past gravitational microlensing searches black holes (BHs) and present details of the observations, analysis, modeling five BH candidates observed with both ground-based photometric surveys Hubble Space Telescope astrometry photometry. detailed results four that show no or low probability lens to be a BH. In these cases, masses are <2 M ⊙ , two likely white dwarfs neutron stars. also methods...
We present Keck/NIRC2 adaptive optics imaging of planetary microlensing event MOA-2007-BLG-400 that resolves the lens star system from source. find MOA-2007-BLG-400L consists a $1.71\pm 0.27 M_{\rm Jup}$ planet orbiting $0.69\pm 0.04M_{\odot}$ K-dwarf host at distance $6.89\pm 0.77\,$kpc Sun. So, this probably resides in Galactic bulge. The planet-host projected separation is only weakly constrained due to close-wide light curve degeneracy; 2$\sigma$ range 0.6--$7.2\,$AU. This mass top end...
Adaptive optics (AO) images from the W. M. Keck Observatory have delivered numerous influential scientific results, including detection of multi-system asteroids, supermassive black hole at center Milky Way, and directly imaged exoplanets. Specifically, precise accurate astrometry these yield was used to measure mass using orbits surrounding star cluster. Despite successes, one major obstacles improved astrometric measurements is spatial temporal variability point-spread function by...
We present the status and plans for Keck All sky Precision Adaptive optics (KAPA) program. KAPA includes (1) an upgrade to I laser guide star adaptive (AO) facility improve image quality coverage, (2) inclusion of AO telemetry-based point spread function estimates with all science exposures, (3) four key programs, (4) educational component focused on broadening participation women underrepresented groups in instrumentation. For this conference we focus upgrades since 2020 SPIE proceedings1...
We measured precise masses of the host and planet in OGLE-2003-BLG-235 system, when lens source were resolving, with 2018 Keck high resolution images. This measurement is agreement observation taken 2005 Hubble Space Telescope (HST). In data, sources not resolved was made using color-dependent centroid shift only. Nancy Grace Roman will measure data typically within 3-4 years peak event which much shorter baseline compared to most mass measurements date. Hence, color dependent be one primary...
We present high angular resolution imaging that reveals the MOA-2008-BLG-379L exoplanet host star using both adaptive optics with Keck NIRC2 instrument and Hubble Space Telescope. These observations reveal planet masses are $M_{\rm host} = 0.434\pm 0.065 M_\odot$, $m_p 2.44 \pm 0.49 M_{\rm Jupiter}$. Their projected separation is $2.70\pm 0.42\,$AU, they located at a distance of $D_L 3.44\pm 0.53\,$kpc toward Galactic center. results contribute to our effort measure stars in \citet{suzuki16}...
Abstract We present an analysis of Galactic bulge stars from Hubble Space Telescope Wide Field Camera 3 observations the Stanek window ( l , b = [0.25, −2.15]) two epochs approximately years apart. This data set is adjacent to provisional Wide-field Infrared Survey WFIRST ) microlensing field. Proper motions are measured for 115,000 down 28th mag in V band and 25th I band, with accuracies 0.5 mas yr −1 (20 km s at ≈ 21. A cut on longitudinal proper motion μ allows us separate disk...
Images obtained with single-conjugate adaptive optics (AO) show spatial variation of the point spread function (PSF) due to both atmospheric anisoplanatism and instrumental aberrations. The poor knowledge PSF across field view strongly impacts ability take full advantage AO capabilities. AIROPA project aims model these variations for NIRC2 imager at Keck Observatory. Here, we present characterization phase aberrations over entire a new metric quantifying quality calibration, fraction...