Speaker
Description
We review the detection and mass-function measurements of free-floating planets (FFPs),
very wide-orbit planets or primordial BH using the microlensing technique.The microlensing surveys
have identified several events with extremely short Einstein radius crossing times, t_E<0.5 days,
and very small angular Einstein radii of theta_E <10μas. Such events are likely produced by
low-mass lenses, potentially down to planetary masses.
MOA collaboration measure the mass function of FFP or very wide orbit planets down to
an Earth mass. These short events are well modeled by a power-law mass function
with a power-law index of 0.96^{+0.47}_{-0.27} for M/M_sun < 0.02. This result suggests that
the FFPs were likely ejected from bound planetary systems. This model predicts that the
Roman Space Telescope will detect about 1000 FFPs, with masses extending down to that of Mars.
The PRIME telescope has begun a near-infrared microlensing survey toward the Galactic center
to measure the masses of FFPs via space-based microlensing parallax in collaboration with Roman.
We also detect isolated stellar-mass BH via astrometric microlensing measurement by HST.
Roman will increase these sample.
We also introduce the biosignature search by NASA Habitable Worlds Observatory (HWO) .