Astrophysical: Gravitational microlensing

  • Publication
    Constraints on the Abundance of Primordial Black Holes from X-Ray Quasar Microlensing Observations: Substellar to Planetary Mass Range
    We use X-ray observations of quasar microlensing (sensitive to smaller compact objects than in the optical) to study the possible presence of a population of...
  • Publication
    First Direct Evidence for Keplerian Rotation in Quasar Inner Broad-line Regions
    We introduce a novel method to derive rotation curves with light-day spatial resolution of the inner regions of lensed quasars. We aim to probe the kinematics...
  • Publication
    Free-floating Planet Mass Function from MOA-II 9 yr Survey toward the Galactic Bulge
    We present the first measurement of the mass function of free-floating planets (FFPs), or very wide orbit planets down to an Earth mass, from the MOA-II...
  • Publication
    Influence of Microlensing on the Active Galactic Nucleus Fe Kalpha Line
    We have studied the influence of gravitational microlensing on the Fe Kalpha line originating from a compact accretion disc of active galactic nuclei. We found...
  • Publication
    KMT-2019-BLG-0842Lb: A Cold Planet below the Uranus/Sun Mass Ratio
    We report the discovery of a cold planet with a very low planet/host mass ratio of q = (4.09 ± 0.27) × 10 -5, which is similar to the ratio of Uranus/Sun (q = 4...
  • Publication
    KMT-2023-BLG-1431Lb: A New q &lt; 10<SUP>‑4</SUP> 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...
  • Publication
    Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star
    We report the analysis of additional multiband photometry and spectroscopy and new adaptive optics (AO) imaging of the nearby planetary microlensing event TCP...
  • Publication
    MOA-2007-BLG-400 A Super-Jupiter-mass Planet Orbiting a Galactic Bulge K-dwarf Revealed by Keck Adaptive Optics Imaging
    We present Keck/NIRC2 adaptive optics imaging of planetary microlensing event MOA-2007-BLG-400 that resolves the lens star system from the source. We find that...
  • Publication
    MOA-2020-BLG-135Lb: A New Neptune-class Planet for the Extended MOA-II Exoplanet Microlens Statistical Analysis
    We report the light-curve analysis for the event MOA-2020-BLG-135, which leads to the discovery of a new Neptune-class planet, MOA-2020-BLG-135Lb. With a...