A5048298822- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Planetary Science and Exploration
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Calibration and Measurement Techniques
- Geomagnetism and Paleomagnetism Studies
- Galaxies: Formation, Evolution, Phenomena
University of Tasmania
2018-2024
University of Bern
2024
Centre National de la Recherche Scientifique
2020-2021
Institut d'Astrophysique de Paris
2020-2021
Sorbonne Université
2020-2021
Vanda Pharmaceuticals (United States)
2018
Mount Stromlo Observatory
2007-2008
Australian National University
2007-2008
We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from ESSENCE supernova survey. derive a set of nature assuming flat Universe. By including (Omega_M, w) baryon acoustic oscillations, we obtain value for static parameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) and Omega_M=0.274^{+0.033}_{-0.020} with best-fit chi^2/DoF 0.96. These results are consistent those reported by SuperNova Legacy Survey in similar...
We describe the implementation and optimization of ESSENCE supernova survey, which we have undertaken to measure equation state parameter dark energy. present a method for optimizing survey exposure times cadence maximize our sensitivity energy w=P/rho c^2 given fixed amount telescope time. For on CTIO 4m telescope, measuring luminosity distances redshifts supernovae at modest (z~0.5 +- 0.2) is optimal determining w. data analysis pipeline based using reliable robust image subtraction find...
We present the analysis of simultaneous high resolution images from {\it Hubble Space Telescope} and Keck Adaptive Optics system planetary event OGLE-2012-BLG-0950 that determine consists a $0.58 \pm 0.04 \rm{M}_\odot$ host star orbited by $39\pm 8 \rm{M}_\oplus$ planet at projected separation $2.54 0.23\,$AU. The is located distance $2.19\pm 0.23$ kpc Earth. This second microlens beyond snow line with mass measured to be in range $20$--$80 \rm{M}_\oplus$. runaway gas accretion process core...
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...
We present the analysis of OGLE-2014-BLG-1760, a planetary system in galactic bulge. combine Keck Adaptive Optics follow-up observations $K$-band with re-reduced light curve data to confirm source and lens star identifications stellar types. The MOA dataset had an important impact on model. find Einstein ring crossing time event be $\sim$ 2.5 days shorter than previous fits, which increases mass-ratio decreases angular size by factor 0.25. Our OSIRIS images obtained 6 years after peak show...
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...
To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass-distance relations. Often, a constraint on the Einstein ring radius measurement obtained from caustic crossing time: This supplemented secondary constraints such as precise parallax and/or measures of luminosity using high angular resolution observations. We resolved source+lens star sub-arcsecond blends in H band adaptive...
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 the analysis of high-resolution images MOA-2013-BLG-220, taken with Keck adaptive optics system 6 years after initial observation, identifying lens as a solar-type star hosting super-Jupiter mass planet. The masses planets and host-stars discovered by microlensing are often not determined from light curve data, while star-planet mass-ratio projected separation in units Einstein ring radius well measured. High-resolution follow-up observations lensing event is complete can resolve...
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...
We report the discovery and orbital determination of 14 trans-Neptunian objects (TNOs) from ESSENCE Supernova Survey difference imaging data set. Two additional discovered in a similar search SDSS-II database were recovered this effort. repeatedly observed fields far solar system ecliptic (–21° < β –5°), reaching limiting magnitudes per observation I ≈ 23.1 R 23.7. examine several newly detected detail, including 2003 UC414, which orbits entirely between Uranus Neptune lies very close to...
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...
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}...
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 years after event, OSIRIS. The 2020 observations yield a source lens separation of $ 56.91 \pm 0.29$ mas, which provides us precise measurement heliocentric proper motion $\mu_{rel,hel} = 7.695 0.039$ mas $yr^{-1}$. measured magnitude K-band as $K_{lens} 18.69 0.04 $. Using these constraints, we refit light curve undertake full reanalysis...
RISTRETTO is a visible high-resolution spectrograph fed by an extreme adaptive optics (AO) system, to be proposed as visitor instrument on ESO VLT. The main science goal of pioneer the detection and atmospheric characterisation exoplanets in reflected light, particular temperate rocky planet Proxima b. will able measure albedos detect features number orbiting nearby stars for first time. It do so combining high-contrast AO system working at diffraction limit telescope spectrograph, via...
We present an analysis of adaptive optics (AO) images from the Keck-I telescope microlensing event MOA-2011-BLG-262. The original discovery paper by Bennett et al. 2014 reports two distinct possibilities for lens system; a nearby gas giant with exomoon companion or very low mass star planetary in galactic bulge. $\sim$10 year baseline between and Keck follow-up observations allows us to detect faint candidate host (star) at $K = 22.3$ mag confirm distant system interpretation. combination...
We present high angular resolution imaging from the {\sl Hubble Space Telescope} combined with adaptive optics results Keck}-II telescope to determine mass of OGLE-2012-BLG-0563L host star and planet be $M_{\rm host} = 0.801\pm 0.033M_\odot$ planet} 1.116 \pm 0.087 M_{\rm Jupiter}$, respectively, located at a distance $D_L 5.46\pm 0.56\,$kpc. There is close-wide degeneracy in light curve models that indicates star-planet projected separation $1.50\pm 0.16\,$AU for close model $8.41\pm...