CaltechAUTHORS
Published July 10, 2020 | Version Published + Submitted
Journal Article Open

Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event

Creators

  • 1. ROR icon Tsinghua University
  • 2. ROR icon Peking University
  • 3. ROR icon Max Planck Institute for Astronomy
  • 4. ROR icon The Ohio State University
  • 5. ROR icon Infrared Processing and Analysis Center
  • 6. ROR icon National Astronomical Observatories
  • 7. ROR icon University of Chinese Academy of Sciences
  • 8. ROR icon California Institute of Technology
  • 9. ROR icon Stardome Observatory
  • 10. ROR icon European Southern Observatory
  • 11. ROR icon Vanderbilt University
  • 12. ROR icon Kumeu Observatory
  • 13. ROR icon Shandong University
  • 14. ROR icon Antelope Hills Observatory
  • 15. ROR icon Bulgarian Academy of Sciences
  • 16. ROR icon Sofia University
  • 17. ROR icon University of Iowa
  • 18. ROR icon Auckland University of Technology
  • 19. ROR icon Weizmann Institute of Science
  • 20. ROR icon University of Arizona
  • 21. ROR icon Canadian Institute for Theoretical Astrophysics

Abstract

We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector π_E using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interferometer (VLTI) GRAVITY observations. Combining this π_E determination with the angular Einstein radius θ_E measured by VLTI-GRAVITY observations, we find that the lens is a star with mass M_L = 0.495±0.063 M⊙ at a distance D_L = 429 ± 21 pc. We find that the blended light basically all comes from the lens. The lens-source proper motion is Μ_(rel,hel) = 26.55±0.36 mas yr⁻¹, so with currently available adaptive-optics instruments, the lens and source can be resolved in 2021. This is the first microlensing event whose lens mass is unambiguously measured by interferometry + satellite-parallax observations, which opens a new window for mass measurements of isolated objects such as stellar-mass black holes.

Additional Information

© 2020 The American Astronomical Society. Received 2019 November 29; revised 2020 May 18; accepted 2020 May 18; published 2020 July 16. We thank Tianshu Wang, Jennifer Yee, Akihiko Fukui, and Naoki Koshimoto for fruitful discussions. We are grateful to Robin Leadbeater and Paolo Berardi for making their spectroscopic observations available to us during the observing campaign. S.D. and P.C. are supported by the National Key R&D Program of China No. 2019YFA0405100 and Projects 11573003 supported by the National Science Foundation of China (NSFC). W.Z., H.Y., S.-S.L., and S.M. acknowledge support by the National Science Foundation of China (grant No. 11821303 and 11761131004). Work by AG was supported by AST-1516842 and by JPL grant 1500811. A.G. received support from the European Research Council under the European Unions Seventh Framework Programme (FP 7) ERC grant Agreement No. [321035]. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. Work by S.M.Hu. was supported by the Natural Science Foundation of Shandong province (No. JQ201702), and the Young Scholars Program of Shandong University (No. 20820162003). W.Z. was supported by the Beatrice and Vincent Tremaine Fellowship at CITA.

Attached Files

Published - Zang_2020_ApJ_897_180.pdf

Submitted - 1912.00038.pdf

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1912.00038.pdf

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Additional details

Identifiers

Eprint ID
104403
Resolver ID
CaltechAUTHORS:20200716-102627218

Related works

Describes
https://arxiv.org/abs/1912.00038 (URL)

Funding

National Key Research and Development Program of China
2019YFA0405100
National Natural Science Foundation of China
11573003
National Natural Science Foundation of China
11821303
National Natural Science Foundation of China
11761131004
NSF
AST-1516842
JPL
1500811
European Research Council (ERC)
321035
NASA/JPL/Caltech
Natural Science Foundation of Shandong Province
JQ201702
Shandong University
20820162003
Canadian Institute for Theoretical Astrophysics

Dates

Created
2020-07-16
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)