Microlensing binaries with candidate brown dwarf companions

Authors

I. G. Shin, Chungbuk National University
C. Han, Chungbuk National University
A. Gould, The Ohio State University
A. Udalski, Uniwersytet Warszawski
T. Sumi, Osaka University
M. Dominik, University of St Andrews
J. P. Beaulieu, Institut d’Astrophysique de Paris
Y. Tsapras, Las Cumbres Observatory Global Telescope Network, Inc
V. Bozza, Università degli Studi di Salerno
M. K. Szymański, Uniwersytet Warszawski
M. Kubiak, Uniwersytet Warszawski
I. Soszyński, Uniwersytet Warszawski
G. Pietrzyński, Uniwersytet Warszawski
R. Poleski, Uniwersytet Warszawski
K. Ulaczyk, Uniwersytet Warszawski
P. Pietrukowicz, Uniwersytet Warszawski
S. Kozłowski, Uniwersytet Warszawski
J. Skowron, The Ohio State University
Wyrzykowski, Uniwersytet Warszawski
F. Abe, Nagoya University
D. P. Bennett, University of Notre Dame
I. A. Bond, Massey University Auckland
C. S. Botzler, The University of Auckland
M. Freeman, The University of Auckland
A. Fukui, Nagoya University
K. Furusawa, Nagoya University
F. Hayashi, Nagoya University
J. B. Hearnshaw, University of Canterbury
S. Hosaka, Nagoya University
Y. Itow, Nagoya University
K. Kamiya, Nagoya University
P. M. Kilmartin, University of Canterbury Mount John Observatory
S. Kobara, Nagoya University

Document Type

Article

Publication Date

12-1-2012

Abstract

Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE- 2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 ± 0.01 M and 0.019 ± 0.002 M for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches. © 2012. The American Astronomical Society. All rights reserved.

Publication Source (Journal or Book title)

Astrophysical Journal

Recommended Citation

Shin, I., Han, C., Gould, A., Udalski, A., Sumi, T., Dominik, M., Beaulieu, J., Tsapras, Y., Bozza, V., Szymański, M., Kubiak, M., Soszyński, I., Pietrzyński, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski., Abe, F., Bennett, D., Bond, I., Botzler, C., Freeman, M., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P., & Kobara, S. (2012). Microlensing binaries with candidate brown dwarf companions. Astrophysical Journal, 760 (2) https://doi.org/10.1088/0004-637X/760/2/116