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the first simultaneous microlensing observations by two space telescopes: spitzer and swift reveal a brown dwarf in event ogle-2015-blg-1319Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax". We report the discovery of a 30-65M J brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of approximately 5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either approximately 0.25 au or approximately 45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.
Document ID
20170004535
Document Type
Reprint (Version printed in journal)
Authors
Shvartzvald, Y.
(Osaka Univ. Osaka, Japan)
Li, Z.
(Las Cumbres Observatory Global Telescope Network, Inc. Goleta, CA, United States)
Udalski, A.
(Warsaw Univ. Observatory Warsaw, Poland)
Gould, A.
(Ohio State Univ. Columbus, OH, United States)
Sumi, T.
(Osaka Univ. Osaka, Japan)
Street, R. A.
(Las Cumbres Observatory Global Telescope Network, Inc. Goleta, CA, United States)
Calchi Novati, S.
(California Inst. of Tech. Pasadena, CA, United States)
Hundertmark, M.
(Copenhagen Univ. Denmark)
Bozza, V.
(Salerno Univ. Italy)
Beichman, C.
(California Inst. of Tech. Pasadena, CA, United States)
Barry, R. K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Bennett, D. P.
(Maryland Univ. Baltimore County Baltimore, MD, United States)
Gehrels, N.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
May 10, 2017
Publication Date
November 7, 2016
Publication Information
Publication: The Astrophysical Journal
Volume: 831
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN42340
Funding Number(s)
CONTRACT_GRANT: NNG17PT01A
CONTRACT_GRANT: JPL Grant 1500811
Distribution Limits
Public
Copyright
Other
Keywords
microlensing events