@article{4a4e187c573542e3b3aaaf0541676042,
title = "Kepler K2 Campaign 9 - I. Candidate short-duration events from the first space-based survey for planetary microlensing",
abstract = "We present the first short-duration candidate microlensing events from the Kepler K2 mission. From late April to early July 2016, Campaign 9 of K2 obtained high temporal cadence observations over a 3.7 deg2 region of the Galactic bulge. Its primary objectives were to look for evidence of a free-floating planet (FFP) population using microlensing, and demonstrate the feasibility of space-based planetary microlensing surveys. Though Kepler K2 is far from optimal for microlensing, the recently developed mcpm photometric pipeline enables us to identify and model microlensing events. We describe our blind event-selection pipeline in detail and use it to recover 22 short-duration events with effective time-scales teff < 10 d previously announced by the OGLE and KMTNet ground-based surveys. We also announce five new candidate events. One of these is a caustic-crossing binary event, modelled in a companion study. The other four have very short durations (teff < 0.1 d) typical of an Earth-mass FFP population. Whilst Kepler was not designed for crowded-field photometry, the K2C9 data set clearly demonstrates the feasibility of conducting blind space-based microlensing surveys towards the Galactic bulge.",
keywords = "Galaxy: bulge, brown dwarfs, gravitational lensing: micro, planetary systems, planets and satellites: detection, stars: statistics",
author = "I. McDonald and E. Kerins and R. Poleski and Penny, {M. T.} and D. Specht and S. Mao and P. Fouqu{\'e} and W. Zhu and W. Zang",
note = "Funding Information: EK acknowledges funding by the UK Science and Technology Facilities Council (grant ST/P000649/1). This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by theNASAScience Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST).We thankOGLEteam for sharing results of their observations.Work by RP was supported by Polish National Agency for Academic Exchange grant Polish Returns 2019. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences (the Strategic Priority Research Program The Emergence of Cosmological Structures Grant No. XDB09000000), and the Special Fund for Astronomy from the Ministry of Finance. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. Work by MTP was partially supported by NASA grants NNX16AC62G and NNG16PJ32C, and Louisiana Board of Regents Support Fund (RCS Award Contract Simple: LEQSF(2020-23)-RDA- 10). This study is based in part on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada France Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. The authorswish to recognize and acknowledge the very significant cultural role and reverence that the summit ofMaunaKea has always had within the indigenous Hawaiian community.We are most fortunate to have the opportunity to conduct observations from this mountain. SMandWZ acknowledge support by the National Science Foundation of China (Grant No. 11821303 and 11761131004). WZ was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) under the funding reference #CITA 490888-16.We finally thank the anonymous referee for constructive feedback. Publisher Copyright: {\textcopyright} 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.",
year = "2021",
month = aug,
day = "1",
doi = "10.1093/mnras/stab1377",
language = "English",
volume = "505",
pages = "5584--5602",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "1365-2966",
publisher = "Oxford University Press",
number = "4",
}