Prediction of Planet Yields by the PRime-focus Infrared Microlensing Experiment Microlensing Survey

Abstract

The PRime-focus Infrared Microlensing Experiment (PRIME) will be the first to conduct a dedicated near-infrared microlensing survey by using a 1.8 m telescope with a wide field of view of 1.45 deg2 at the South African Astronomical Observatory. The major goals of the PRIME microlensing survey are to measure the microlensing event rate in the inner Galactic bulge to help design the observing strategy for the exoplanet microlensing survey by the Nancy Grace Roman Space Telescope and to make a first statistical measurement of exoplanet demographics in the central bulge fields where optical observations are very difficult owing to the high extinction in these fields. Here we conduct a simulation of the PRIME microlensing survey to estimate its planet yields and determine the optimal survey strategy, using a Galactic model optimized for the inner Galactic bulge. In order to maximize the number of planet detections and the range of planet mass, we compare the planet yields among four observation strategies. Assuming the Cassan et al. mass function as modified by Penny et al., we predict that PRIME will detect planetary signals for 42–52 planets (1–2 planets with M p ≤ 1M ⊕, 22−25 planets with mass 1M ⊕ < M p ≤ 100M ⊕, 19–25 planets 100M ⊕ < M p ≤ 10, 000M ⊕), per year depending on the chosen observation strategy.

Measurement of Dependence of Microlensing Planet Frequency on the Host Star Mass and Galactocentric Distance by Using a Galactic Model

“…The Korea Microlensing Telescope Network (KMTNet; Kim et al 2016) has operated their microlensing survey since 2016, and more than 200 planets have already been detected. The PRime-focus Infrared Microlensing Experiment (PRIME) began their survey toward the Galactic bulge and center in 2023 (Kondo et al 2023;Yama et al 2023). PRIME is expected to discover 42-50 planets per year (Kondo et al 2023).…”

“…The PRime-focus Infrared Microlensing Experiment (PRIME) began their survey toward the Galactic bulge and center in 2023 (Kondo et al 2023;Yama et al 2023). PRIME is expected to discover 42-50 planets per year (Kondo et al 2023). The Nancy Grace Roman Space Telescope is planned to launch in late 2026 (Spergel et al 2015) and a total of ∼1400 planets are expected to be discovered (Penny et al 2019).…”

Toward Measuring the Microlensing Event Rate in the Galactic Center. I. Event Detection from the UKIRT Microlensing Survey Data

“…Then, combining the events detected in this paper (i.e., Paper I), we can obtain the true NIR event rates toward the Galactic center. After that, we plan to apply the well-developed methodology to the VVV NIR survey and the ongoing NIR survey through the PRime-focus Infrared Microlensing Experiment (PRIME; Kondo et al 2023). In addition, we may analyze the possible anomalous events to obtain the binary mass-ratio distributions in the direction toward the Galactic center.…”

Astrometric Microlensing by Primordial Black Holes with the Roman Space Telescope

“…The GBTDS will survey ≈2 deg 2 over 5 yr in the infrared wavelengths. In addition to benefiting from increased microlensing event rates in the infrared (e.g., Gould 1994;McGill et al 2019;Husseiniova et al 2021;Kaczmarek et al 2022;Luberto et al 2022;Kaczmarek et al 2024;Kondo et al 2023;Wen et al 2023), the GBTDS will take simultaneous photometry and astrometry at a 15 minute cadence during an observing season.…”