skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262

Abstract

We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t {sub E} = 3.8 day, a companion mass ratio q = 4.7 × 10{sup –3}, and a very high or high lens-source relative proper motion μ{sub rel} = 20 mas yr{sup –1} or 12 mas yr{sup –1} (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass 'moon'. The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment, we measure the source proper motion that is small, μ{sub s}=(−2.3,−0.9)±(2.8,2.6) mas yr{sup −1} in a (north, east) Galactic coordinate frame. These values are then important input into a Bayesian analysis of the event presented in amore » companion paper by Bennett et al.« less

Authors:
 [1]; ;
  1. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
Publication Date:
OSTI Identifier:
22357056
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 785; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GALAXIES; GRAVITATIONAL LENSES; MASS; MOON; ORBITS; PLANETS; PROBABILITY; PROPER MOTION

Citation Formats

Skowron, Jan, Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, Udalski, Andrzej, Szymański, Michał K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm, and others, and. New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262. United States: N. p., 2014. Web. doi:10.1088/0004-637X/785/2/156.
Skowron, Jan, Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, Udalski, Andrzej, Szymański, Michał K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm, & others, and. New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262. United States. https://doi.org/10.1088/0004-637X/785/2/156
Skowron, Jan, Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, Udalski, Andrzej, Szymański, Michał K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm, and others, and. 2014. "New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262". United States. https://doi.org/10.1088/0004-637X/785/2/156.
@article{osti_22357056,
title = {New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262},
author = {Skowron, Jan and Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 and Udalski, Andrzej and Szymański, Michał K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm and others, and},
abstractNote = {We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t {sub E} = 3.8 day, a companion mass ratio q = 4.7 × 10{sup –3}, and a very high or high lens-source relative proper motion μ{sub rel} = 20 mas yr{sup –1} or 12 mas yr{sup –1} (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass 'moon'. The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment, we measure the source proper motion that is small, μ{sub s}=(−2.3,−0.9)±(2.8,2.6) mas yr{sup −1} in a (north, east) Galactic coordinate frame. These values are then important input into a Bayesian analysis of the event presented in a companion paper by Bennett et al.},
doi = {10.1088/0004-637X/785/2/156},
url = {https://www.osti.gov/biblio/22357056}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 785,
place = {United States},
year = {Sun Apr 20 00:00:00 EDT 2014},
month = {Sun Apr 20 00:00:00 EDT 2014}
}