I. A. Bond
A5067611955- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- SAS software applications and methods
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Spacecraft Design and Technology
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle Detector Development and Performance
- Space Exploration and Technology
- Nuclear Physics and Applications
- Planetary Science and Exploration
- Chronic Obstructive Pulmonary Disease (COPD) Research
Massey University
2016-2025
University of Canterbury
1999-2023
Ministry of Agriculture and Natural Resource
1999-2023
Korea Astronomy and Space Science Institute
2023
Korea University of Science and Technology
2023
Chungbuk National University
2023
Tsinghua University
2023
Max Planck Institute for Astronomy
2023
The Ohio State University
2023
University of Salerno
2023
We describe observations carried out by the MOA group of Galactic Bulge during 2000 that were designed to detect efficiently gravitational microlensing faint stars in which magnification is high and/or short duration. These events are particularly useful for studies extra-solar planets and stars. Approximately 17 degrees square monitored at a sampling rate up 6 times per night. The images analysed real-time using difference imaging technique. Twenty candidates detected, 8 alerted community...
We describe the WFCAM Science Archive, which is primary point of access for users data from wide-field infrared camera on United Kingdom Infrared Telescope (UKIRT), especially science catalogue products UKIRT Deep Sky Survey. database design with emphasis those aspects system that enable to fully exploit survey sets in a variety different ways. give details database-driven curation applications take standard nightly pipeline-processed and calibrated files production science-ready sets....
Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], now have 58 microlensed bulge dwarfs subgiants that been homogeneously analysed. The main characteristics sample findings can be drawn are: (i) metallicity distribution (MDF) is wide spans all metallicities between [Fe/H]=-1.9 to +0.6; (ii) dip MDF around solar was apparent our previous smaller...
We present observations of the unusual microlensing event OGLE 2003-BLG-235/MOA 2003-BLG-53. In this event, a short-duration (~7 days) low-amplitude deviation in light curve due to single-lens profile was observed both MOA (Microlensing Observations Astrophysics) and (Optical Gravitational Lensing Experiment) survey observations. find that features can only be reproduced using binary model with an extreme (planetary) mass ratio 0.0039 for lensing system. If lens system comprises...
Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing all except Mercury. We report detection a with microlensing. identify two masses ∼0.71 and ∼0.27 times mass Jupiter orbital separations ∼2.3 ∼4.6 astronomical units orbiting primary star ∼0.50 at distance ∼1.5 kiloparsecs. This...
We present the first measurement of planet frequency beyond "snow line," for planet-to-star mass-ratio interval −4.5 < log q −2, corresponding to range ice giants gas giants. find at mean mass ratio = 5 × 10−4 with no discernible deviation from a flat (Öpik's law) distribution in log-projected separation s. The determination is based on sample six planets detected intensive follow-up observations high-magnification (A>200) microlensing events during 2005–2008. sampled host stars have typical...
ABSTRACT We report the results of statistical analysis planetary signals discovered in MOA-II microlensing survey alert system events from 2007 to 2012. determine sensitivity as a function planet–star mass ratio, q , and projected separation, s Einstein radius units. find that mass-ratio is not single power law, but has change slope at ∼ 10 −4 corresponding ∼20 M ⊕ for median host-star ∼0.6 . significant 23 1474 are well-characterized by data alone. Data other groups used only characterize...
The first detected gravitational wave from a neutron star merger was GW170817. In this study, we present J-GEM follow-up observations of SSS17a, an electromagnetic counterpart SSS17a shows 2.5-mag decline in the $z$-band 1.7 days to 7.7 after merger. Such rapid is not comparable with supernovae light curves at any epoch. color also evolves rapidly and becomes redder for later epochs; $z-H$ changed by approximately 2.5 mag period 0.7 days. evolution both optical brightness are consistent...
Abstract We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). used Hubble Space Telescope (HST) to carry out precise astrometry source star long-duration ( t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in direction Galactic bulge. HST imaging, conducted at eight epochs over interval 6 yr, reveals a clear relativistic astrometric deflection...
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 detect a Neptune mass ratio (q ≃ 8 × 10-5) planetary companion to the lens star in extremely high magnification (A ~ 800) microlensing event OGLE-2005-BLG-169. If parent is main-sequence star, it has M 0.5 M☉, implying planet of ~13 M⊕ and projected separation ~2.7 AU. When intensely monitored over their peak, high-magnification events similar OGLE-2005-BLG-169 have nearly complete sensitivity planets with separations 0.6-1.6 Einstein radii, corresponding 1.6-4.3 AU present case. Only two...
We report the discovery of a several-Jupiter-mass planetary companion to primary lens star in microlensing event OGLE-2005-BLG-071. Precise (≲1%) photometry at peak yields an extremely high signal-to-noise ratio detection deviation from light curve expected isolated lens. The character this is easily and unambiguously discernible gross features curve. Detailed modeling tightly constrained planet-star mass q = mp/M 0.0071 ± 0.0003. This second robust planet with microlensing, demonstrating...
We report the detection of an extrasolar planet mass ratio q ~ 2 x 10^(-4) in microlensing event MOA-2007-BLG-192. The best fit model shows both parallax and finite source effects, these can be combined to obtain lens masses M = 0.060 (+0.028 -0.021) M_sun for primary m 3.3 (+4.9 -1.6) M_earth planet. However, observational coverage planetary deviation is sparse incomplete, radius was estimated without benefit a star color measurement. As result, 2-sigma limits on measurements are weak....
We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with planet–star mass ratio q = [9.5 ± 2.1] × 10−5 via gravitational microlensing. The planetary deviation was detected in real-time thanks to high cadence Microlensing Observations Astrophysics survey, light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns stellar distance at Ml 0.64+0.21−0.26 M☉ Dl 5.9+0.9−1.4 kpc, respectively, so separation are Mp 20+7−8 M⊕ 3.3+1.4−0.8 AU,...
We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, second planet discovered by microlensing and first in a high-magnification event. These include photometric astrometric measurements from Hubble Space Telescope, as well constraints higher order effects extracted ground-based light curve, such microlens parallax, planetary orbital motion finite-source effects. Our primary analysis leads conclusion that host Jovian OGLE-2005-BLG-071Lb is an M dwarf foreground...
We present the first microlensing candidate for a free-floating exoplanet–exomoon system, MOA-2011-BLG-262, with primary lens mass of Mhost ∼ 4 Jupiter masses hosting sub-Earth moon. The argument an exomoon hinges on system being relatively close to Sun. data constrain product MLπrel where ML is and πrel lens–source relative parallax. If nearby (large πrel), then small (a few masses) companion sub-Earth-mass exomoon. best-fit solution has large proper motion, μrel = 19.6 ± 1.6 mas yr−1,...
We present a detailed elemental abundance study of 90 F and G dwarf, turn-off, subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y Ba) have been determined. Four main findings are presented: (1) wide metallicity distribution with distinct peaks at [Fe/H] = −1.09, −0.63, −0.20, + 0.12, 0.41; (2) ahigh fraction intermediate-age to young where > 0...
We report the detection of cool, Jovian-mass planet MOA-2007-BLG-400Lb. The was detected in a high-magnification microlensing event (with peak magnification A_max = 628) which primary lens transited source, resulting dramatic smoothing event. angular extent region perturbation due to is significantly smaller than size and as result planetary signature also smoothed out by finite source size. Thus deviation from single-lens fit broad relatively weak (~ few percent). Nevertheless, we...
Aims. We report the discovery of a planet with high planet-to-star mass ratio in microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over 12-day interval, one longest for any planetary event. The host is an M dwarf, range 0.07 M⊙ < Mhost 0.49 at 90% confidence. planet-star q = 0.0132 ± 0.003 has been measured extremely well, so best-estimated mass, mp 2.6 Jupiter masses median 0.19 M⊙.
We present the first example of binary microlensing for which parameter measurements can be verified (or contradicted) by future Doppler observations. This test is made possible a confluence two relatively unusual circumstances. First, lens bright enough (I=15.6) to permit measurements. Second, we measure not only usual 7 binary-lens parameters, but also 'microlens parallax' (which yields mass) and components instantaneous orbital velocity. Thus measure, effectively, 6 'Kepler+1' parameters...
[ABRIDGED] Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba) stellar ages for 26 microlensed dwarf subgiant stars in the Galactic bulge. The analysis is based equivalent width measurements standard 1-D LTE MARCS model atmospheres. We also NLTE Li line synthesis of 7Li at 670.8 nm. show that bulge metallicity distribution (MDF)...
Abstract Recent detection of gravitational waves from a neutron star (NS) merger event GW170817 and identification an electromagnetic counterpart provide unique opportunity to study the physical processes in NS mergers. To derive properties ejected material merger, we perform radiative transfer simulations kilonova, optical near-infrared emissions powered by radioactive decays r-process nuclei synthesized merger. We find that observed emission lasting for &gt;10 d is explained 0.03 M⊙...
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...