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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 742350.0, MPI für Astronomie / Publikationen_mpia
Toward a Galactic distribution of planets. I. Methodology and planet sensitivities of the 2015 high-cadence Spitzer microlens sample
Authors:Zhu, W.; Udalski, A.; Calchi Novati, S.; Chung, S. -. J.; Jung, Y. K.; Ryu, Y. -. H.; Shin, I. -. G.; Gould, A.; Lee, C. -. U.; Albrow, M. D.; Yee, J. C.; Han, C.; Hwang, K. -. H.; Cha, S. -. M.; Kim, D. -. J.; Kim, H. -. W.; Kim, S. -. L.; Kim, Y. -. H.; Lee, Y.; Park, B. -. G.; Pogge, R. W.; Poleski, R.; Mróz, P.; Pietrukowicz, P.; Skowron, J.; Szymański, M. K.; KozLowski, S.; Ulaczyk, K.; Pawlak, M.; Beichman, C.; Bryden, G.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Wibking, B.
Date of Publication (YYYY-MM-DD):2017
Title of Journal:The Astronomical Journal
Issue / Number:5
Start Page:id. 210 (22 pp)
Audience:Not Specified
Abstract / Description:We analyze an ensemble of microlensing events from the 2015 Spitzer microlensing campaign, all of which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations from Spitzer and the ground yield measurements of the microlensing parallax vector {{\boldsymbol{π }}}{{E}}, from which compact constraints on the microlens properties are derived, including ≲25% uncertainties on the lens mass and distance. With the current sample, we demonstrate that the majority of microlenses are indeed in the mass range of M dwarfs. The planet sensitivities of all 41 events in the sample are calculated, from which we provide constraints on the planet distribution function. In particular, assuming a planet distribution function that is uniform in {log}q, where q is the planet-to-star mass ratio, we find a 95% upper limit on the fraction of stars that host typical microlensing planets of 49%, which is consistent with previous studies. Based on this planet-free sample, we develop the methodology to statistically study the Galactic distribution of planets using microlensing parallax measurements. Under the assumption that the planet distributions are the same in the bulge as in the disk, we predict that ∼1/3 of all planet detections from the microlensing campaigns with Spitzer should be in the bulge. This prediction will be tested with a much larger sample, and deviations from it can be used to constrain the abundance of planets in the bulge relative to the disk.
Free Keywords:gravitational lensing: micro; methods: statistical; planetary systems; planets and satellites: dynamical evolution and stability
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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