Probability of simultaneous parallax detection for free-floating planet microlensing events near Galactic Centre. Issue 3 (17th April 2020)

• Record Type: Journal Article
• Authors: Ban, M
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 494:Issue 3(2020)
• Page Start: 3235
• Page End: 3252
• Publication Date: 2020-04-17
• Subjects: parallaxes -- Sun: infrared -- planets and satellites: detection -- planets and satellites: gaseous planets -- planets and satellites: terrestrial planets; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa786
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The event rate and the efficiency of mass estimation for free-floating planet (FFP) microlensing events were determined from the simulation of the simultaneous parallax observations by Euclid, WFIRST, and LSST. The stellar population from the Besançon Galactic model toward ( l, b ) = (1°, −1.°75) was applied to our 3D microlensing model, and 30 000 parallax observations were simulated for each following FFP lens masses: Jupiter mass, Neptune mass, and Earth mass assuming the population of one FFP per star. The interstellar dust, unresolved stellar background, nearby star blending was modelled. A signal-to-noise limit considering a finite source effect determined the event detectability. The Euclid – WFIRST combination yielded 30.7 Jupiter-mass FFPs during two 30-d periods per year in parallax observation. The parallax event rate decreases to 3.9 FFPs for Earth-mass planets. The mass estimation from the parallax light curve allowed recovery of FFP masses to within a factor of 2 for 20–26 per cent of cases. The Euclid –LSST combination yielded 34.5 Jupiter-mass FFPs down to 0.5 Earth-mass FFPs for the same periods and the mass is recovered to within a factor of 2 in 20–40 per cent of cases. The event rate will be normalized by the unknown FFP abundance to recover the number of expected detections.