UKIRT microlensing surveys as a pathfinder for $WFIRST$: The detection of five highly extinguished low-$|b|$ events

Abstract

Optical microlensing surveys are restricted from detecting events near the Galactic plane and center, where the event rate is thought to be the highest, due to the high optical extinction of these fields. In the near-infrared (NIR), however, the lower extinction leads to a corresponding increase in event detections and is a primary driver for the wavelength coverage of the $WFIRST$ microlensing survey. During the 2015 and 2016 bulge observing seasons we conducted NIR microlensing surveys with UKIRT in conjunction with and in support of the $Spitzer$ and $Kepler$ microlensing campaigns. Here we report on five highly extinguished ($A_H=0.81-1.97$), low-Galactic latitude ($-0.98\le b\le -0.36$) microlensing events discovered from our 2016 survey. Four of them were monitored with an hourly cadence by optical surveys but were not reported as discoveries, likely due to the high extinction. Our UKIRT surveys and suggested future NIR surveys enable the first measurement of the microlensing event rate in the NIR. This wavelength regime overlaps with the bandpass of the filter in which the $WFIRST$ microlensing survey will conduct its highest-cadence observations, making this event rate derivation critically important for optimizing its yield.

12 pages, 3 figures, 2 tables. ApJL submitted

References in corpus (4)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The UKIRT Wide Field Camera ZYJHK Photometric System: Calibration from 2MASS
• Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
• A Terrestrial Planet in a ~1 AU Orbit Around One Member of a ~15 AU Binary

Cited by in corpus (15)

• Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey II: Free-Floating Planet Detection Rates
• Systematic KMTNet Planetary Anomaly Search. V. Complete Sample of 2018 Prime-Field
• MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Lightcurve Analysis and Keck AO Imaging
• OGLE-2016-BLG-0613LABb: A Microlensing Planet in a Binary System
• OGLE-2016-BLG-1190Lb: First Spitzer Bulge Planet Lies Near the Planet/Brown-Dwarf Boundary
• OGLE-2017-BLG-0173Lb: Low Mass-Ratio Planet in a "Hollywood" Microlensing Event
• Prediction of Planet Yields by the PRime-focus Infrared Microlensing Experiment Microlensing Survey
• A Machine Learning Classifier for Microlensing in Wide-Field Surveys
• $Spitzer$ Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarf
• Dark lenses through the dust: parallax microlensing events in the VVV
• Architecture Classification for Extrasolar Planetary Systems
• OGLE-2018-BLG-0022: A Nearby M-dwarf Binary
• Microlensing signatures of extended dark objects using machine learning
• The first Palomar Gattini-IR catalog of J-band light curves: construction and public data release
• A Near-Infrared Extinction and Reddening Map Towards the Galactic Bulge Using UKIRT