WFIRST and EUCLID: Enabling the Microlensing Parallax Measurement from Space

Bachelet, E.; Penny, Matthew T.

doi:10.3847/2041-8213/ab2da5

Cited by 20 publications

(21 citation statements)

References 62 publications

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“…The stellar mass range can also be probed by lensing of Type-Ia supernovae [46]. Using parallax measurements in lensing can probe asteroid to planet masses [47,48]. Should numerous microlensing events be detected, the data on lightcurves may help us estimate the subhalo mass function and perform dark matter astrometry, in particular help identify departures from the Standard Halo Model such as the presence of tidal streams, as already constrained by weak lensing in the time domain [49,50].…”

Section: Discussionmentioning

confidence: 99%

Gravitational microlensing by dark matter in extended structures

2020

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Dark matter may be in the form of non-baryonic structures such as compact subhalos and boson stars. Structures weighing between asteroid and solar masses may be discovered via gravitational microlensing, an astronomical probe that has in the past helped constrain the population of primordial black holes and baryonic machos. We investigate the non-trivial effect of the size of and density distribution within these structures on the microlensing signal, and constrain their populations using the eros- and ogle-iv surveys. Structures larger than a solar radius are generally constrained more weakly than point-like lenses, but stronger constraints may be obtained for structures with mass distributions that give rise to caustic crossings or produce larger magnifications.

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Section: Discussionmentioning

confidence: 99%

Gravitational microlensing by dark matter in extended structures

2020

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“…While the exact orbital elements are not known yet, it is safe to assume that the orbits will be comparable to the current orbit of the Gaia telescope, with an orbital radius R ∼ 300, 000 km and a period of ∼ 180 days. Using these parameters, Bachelet & Penny (2019) have shown that simultaneous observations from the two telescopes unlock the parallax measurement down to the FFP regime, if the telescope's separation is at least ≥ 100, 000 km. We use these parameters for the rest of this work.…”

Section: Orbital Elementsmentioning

confidence: 99%

“…Recently, it has been demonstrated that the Roman observations from the Earth-Sun L2 point will be sufficient to detect parallax for microlensing events with t E 5 days, due to the orbit of the L2 point around the Sun (Bachelet & Penny 2019). This will ensure strong constraints on the mass and distance of the ∼ 1, 500 bound planets expected to be detected by Roman (Penny et al 2019).…”

Section: Mass-distance Relations From Lens-source Relative Proper Motionmentioning

confidence: 99%

“…However, simultaneous observations from Euclid and Roman are ideal to measure the parallax for such events (Bachelet & Penny 2019). This is of particular interest because, as noted, FFPs are expected to produce short events with time scales of hours to days (Eq 3).…”

Section: Mass-distance Relations From Lens-source Relative Proper Motionmentioning

confidence: 99%

“…This implies that θ E will be measured for most of these events, because θ * will be almost systematically known for events detected by Roman. On the other side, Bachelet & Penny (2019) shows that the microlensing parallax will not be detected by Roman alone for events with t E ≤ 3 days, i.e. outside of the FFP regime.…”

Section: Introductionmentioning

confidence: 96%

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Euclid-Roman joint microlensing survey: early mass measurement, free floating planets and exomoons

Bachelet¹,

Specht²,

Penny³

et al. 2022

Preprint

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As the Kepler mission has done for hot exoplanets, the ESA Euclid and NASA Roman missions have the potential to create a breakthrough in our understanding of the demographics of cool exoplanets, including unbound, or "free-floating", planets (FFPs). Roman will dedicate part of its core survey program to the detection of cool exoplanets via microlensing, while Euclid may undertake a microlensing program as an ancillary science goal. In this study, we demonstrate the complementarity of the two missions and propose two joint-surveys to better constrain the mass and distance of microlensing events. We first demonstrate that an early brief Euclid survey (∼ 7 h) of the Roman microlensing fields will allow the measurement of at least 30% of the events' relative proper motions µ rel and 42% of the lens magnitudes. This survey would place strong constraints on the mass and distance on thousands of microlensing events observed by Roman just after the first year of observation. Then, we study the potential that simultaneous observations by Roman and Euclid to enable the measurement of the microlensing parallax for the shortest microlensing events and, ultimately, obtain a direct measurement of the masses, distances and transverse motions of FFPs. Using detailed simulations of the joint detection yield we show that within one year Roman-Euclid observations will be at least an order of magnitude more sensitive than current groundbased measurements. The recent tentative detection of an excess of short-duration events by the OGLE survey is consistent with a scenario of up to 10 Earth-mass FFPs per Galactic star. For such a scenario a joint Roman-Euclid campaign should detect around 130 FFP events within a year, including 110 with measured parallax that strongly constrain the FFP mass, and around 30 FFP events with direct mass and distance measurements. The ability of the joint survey to completely break the microlens mass-distance-velocity degeneracy for a significant subset of events provides a unique opportunity to verify unambiguously the FFP hypothesis or else place abundance limits for FFPs between Earth and Jupiter masses that are up to two orders of magnitude stronger than provided by groundbased surveys. Finally, we study the capabilities of the joint survey to enhance the detection and charcterization of exomoons, and found that it could lead to the detection of the first exomoon.

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Finding Planets via Gravitational Microlensing

Batista¹

2017

Handbook of Exoplanets

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Since the first microlensing planet discovery in 2003, more than 200 planets have been detected with gravitational microlensing, in addition to several freefloating planet and black hole candidates. In this chapter the microlensing theory is presented by introducing the numerical methods used to solve binary and triple lens problems and how these lead to the characterisation of the planetary systems. Then the microlensing planetary detection efficiency is discussed, with an emphasis on cold planets beyond the snow line. Furthermore, it will be explained how the planetary characterisation can be facilitated when the microlensing light curves exhibit distortions due to second order effects such as parallax, planetary orbital motion, and extended source. These second order effects can be turned to our advantage, and become useful to ultimately better characterise the planetary systems, but they can also introduce degeneracies in the light curve models. It will be explained how the use of modern observational and computational techniques enables microlensers to solve these degeneracies and estimate the planetary system parameters with very high accuracy. Then a review of the main discoveries to date will be presented while exploring the recent statistical results from high-cadence ground-based surveys and space-based observations, especially on the planet mass function. Finally, future prospects are discussed, with the expected advances from dedicated space missions, extending the planet sensitivity range down to Mars mass.

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WFIRST and EUCLID: Enabling the Microlensing Parallax Measurement from Space

Cited by 20 publications

References 62 publications

Gravitational microlensing by dark matter in extended structures

Gravitational microlensing by dark matter in extended structures

Euclid-Roman joint microlensing survey: early mass measurement, free floating planets and exomoons

Finding Planets via Gravitational Microlensing

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