2019/03/21 by B. Scott Gaudi, Rachel Akeson, Gaudi, B. Scott +44
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.1903.08986
openalex publication_date 2019/03/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Wide Field Infrared Survey Telescope (WFIRST) will monitor ∼ 2 deg2 toward the Galactic bulge in a wide (∼ 1-2~μm) W149 filter at 15-minute cadence with exposure times of ∼50s for 6 seasons of 72 days each, for a total ∼41,000 exposures taken over ∼432 days, spread over the 5-year prime mission. This will be one of the deepest exposures of the sky ever taken, reaching a photon-noise photometric precision of 0.01 mag per exposure and collecting a total of ∼ 109 photons over the course of the survey for a W149\rm AB∼ 21 star. Of order 4 × 107 stars will be monitored with W149\rm AB<21, and 108 stars with W145\rm AB<23. The WFIRST microlensing survey will detect ∼54,000 microlensing events, of which roughly 1% (∼500) will be due to isolated black holes, and ∼3% (∼1600) will be due to isolated neutron stars. It will be sensitive to (effectively) isolated compact objects with masses as low as the mass of Pluto, thereby enabling a measurement of the compact object mass function over 10 orders of magnitude. Assuming photon-noise limited precision, it will detect ∼ 105 transiting planets with sizes as small as ∼ 2~R_⊕, perform asteroseismology of ∼ 106 giant stars, measure the proper motions to ∼ 0.3% and parallaxes to ∼ 10% for the ∼ 6 × 106 disk and bulge stars in the survey area, and directly detect ∼ 5 × 103 Trans-Neptunian objects (TNOs) with diameters down to ∼ 10 km, as well as detect ∼ 103 occulations of stars by TNOs during the survey. All of this science will completely serendipitous, i.e., it will not require modifications of the WFIRST optimal microlensing survey design. Allowing for some minor deviation from the optimal design, such as monitoring the Galactic center, would enable an even broader range of transformational science.