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Astronomy Colloquium

Wednesday, February 24, 2021
4:00pm to 5:00pm
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NIR microlensing exoplanet search by PRIME and Roman
Takahiro Sumi, Professor, Department of Earth and Space Science, Osaka University,

We report the status of the NIR microlensing exoplanet search project, the Prime-focus Infrared Microlensing Experiment (PRIME). We are building a new 1.8m wide field infrared telescope at the Sutherland in South Africa.
One of the largest NIR camera will be build by using four H4RG-10 detectors loaned from the Roman project. 
Thanks to 1.3 deg.^2 FOV, we can conduct the first high cadence microlensing survey in H-band toward the central region of the galactic bulge, where high dust extinction prevents optical observations.  Because the stellar density is higher at the lower galactic latitude, we expect higher event rate. We can compare the planet abundances in high and low stellar density for the first time, which is important for the study of the planetary formation scenarios.  The event rate map produced by PRIME can be used to optimize the Roman observing fields.  If the PRIME telescope and Roman observe the same fields simultaneously, different light curves will be observed due to the different line of sights, so-called the space-based microlensing parallax. This enables us to measure the mass and the distance of the lens system and enhance the Roman's yields.The telescope will also be used for the ToO observations for various transients including GW, GRB and so on.

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