CaltechAUTHORS
Published December 2021 | Version Accepted Version + Published
Journal Article Open

Using Source Proper Motion to Validate Terrestrial Parallax: OGLE-2019-BLG-1058

Creators

Abstract

We show that because the conditions for producing terrestrial microlens parallax (TPRX; i.e., a nearby disk lens) will also tend to produce a large lens-source relative proper motion (μ_(rel)), source proper motion (μ_S) measurements in general provide a strong test of TPRX signals, which Gould & Yee (2013) showed were an important probe of free-floating planet (FFP) candidates. As a case study, we report a single-lens/single-source microlensing event designated as OGLE-2019-BLG-1058. For this event, the short timescale (∼2.5 days) and very fast μ_(rel) (∼17.6 mas yr⁻¹) suggest that this isolated lens is an FFP candidate located in the disk of our Galaxy. For this event, we find a TPRX signal consistent with a disk FFP, but at low significance. A direct measurement of the μ_S shows that the large μ_(rel) is due to an extreme μ_S, and thus, the lens is consistent with being a very-low-mass star in the bulge and the TPRX measurement is likely spurious. By contrast, we show how a precise measurement of μ_S with the mean properties of the bulge proper motion distribution would have given the opposite result; i.e., provided supporting evidence for an FFP in the disk and the TPRX measurement.

Additional Information

© 2021. The American Astronomical Society. Received 2021 August 5; revised 2021 September 17; accepted 2021 September 28; published 2021 November 26. This research has made use of the KMTNet system operated by the Korea Astronomy and Space Science Institute (KASI), and the data were obtained at three host sites of CTIO in Chile, SAAO in South Africa, and SSO in Australia. Work by A.G. was supported by JPL grant 1500811. Work by C.H. was supported by grants of the National Research Foundation of Korea (2017R1A4A1015178 and 2019R1A2C2085965).

Attached Files

Published - Shin_2021_AJ_162_267.pdf

Accepted Version - 2108.02499.pdf

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2108.02499.pdf

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Additional details

Identifiers

Eprint ID
112638
Resolver ID
CaltechAUTHORS:20211222-204086900

Related works

Describes
https://arxiv.org/abs/2108.02499 (URL)

Funding

JPL
1500811
National Research Foundation of Korea
2017R1A4A1015178
National Research Foundation of Korea
2019R1A2C2085965

Dates

Created
2021-12-22
Created from EPrint's datestamp field
Updated
2022-07-25
Created from EPrint's last_modified field