Microlensing Parallax for Observers in Heliocentric Motion
- Creators
- Calchi Novati, S.
- Scarpetta, G.
Abstract
Motivated by the ongoing Spitzer observational campaign, and the forthcoming K2 one, we revisit, working in an heliocentric reference frame, the geometrical foundation for the analysis of the microlensing parallax, as measured with the simultaneous observation of the same microlensing event from two observers with relative distance of order au. For the case of observers at rest, we discuss the well-known fourfold microlensing parallax degeneracy and determine an equation for the degenerate directions of the lens trajectory. For the case of observers in motion, we write down an extension of the Gould relationship between the microlensing parallax and the observable quantities and, at the same time, highlight the functional dependence of these same quantities from the timescale of the underlying microlensing event. Furthermore, through a series of examples, we show the importance of taking into account themotion of the observers to correctly recover the parameters of the underlying microlensing event. In particular, we discuss the cases of the amplitude of the microlensing parallax and that of the difference of the timescales between the observed microlensing events, which are key to understand the breaking of the microlensing parallax degeneracy. Finally, we consider the case of the simultaneous observation of the same microlensing event from the ground and two satellites, a case relevant for the expected joint K2 and Spitzer observational programs in 2016.
Additional Information
© 2016 The American Astronomical Society. Received 2015 December 30; accepted 2016 February 20; published 2016 June 20. We thank A. Gould for valuable discussions. SCN acknowledges support by JPL grant 1500811. GS thanks NExScI for hospitality at Caltech during part of this work.Attached Files
Published - apj_824_2_109.pdf
Submitted - 1512.09141v2.pdf
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Additional details
- Eprint ID
- 70401
- Resolver ID
- CaltechAUTHORS:20160916-124718063
- 1500811
- JPL
- Created
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2016-09-16Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field