Ground-based parallax confirmed by Spitzer: binary microlensing event MOA-2015-BLG-020

Abstract

We present the analysis of the binary gravitational microlensing event MOA-2015-BLG-020. The event has a fairly long timescale (about 63 days) and thus the light curve deviates significantly from the lensing model that is based on the rectilinear lens-source relative motion. This enables us to measure the microlensing parallax through the annual parallax effect. The microlensing parallax parameters constrained by the ground-based data are confirmed by the Spitzer observations through the satellite parallax method. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined. It is found that the binary lens is composed of two dwarf stars with masses $M_1=0.606\pm 0.028M_{\odot }$ and $M_2=0.125\pm 0.006M_{\odot }$ in the Galactic disk. Assuming the source star is at the same distance as the bulge red clump stars, we find the lens is at a distance $D_L=2.44\pm 0.10kpc$. In the end, we provide a summary and short discussion of all published microlensing events in which the annual parallax effect is confirmed by other independent observations.

16 pages, 5 figures

References in corpus (32)

• emcee: The MCMC Hammer
• A method for optimal image subtraction
• Las Cumbres Observatory Global Telescope Network
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF
• OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens
• Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
• A Jovian-mass Planet in Microlensing Event OGLE-2005-BLG-071
• A New Algorithm For Difference Image Analysis
• OGLE-2005-BLG-071Lb, the Most Massive M-Dwarf Planetary Companion?
• Binary microlensing event OGLE-2009-BLG-020 gives a verifiable mass, distance and orbit predictions
• MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
• Masses and Orbital Constraints for the OGLE-2006-BLG-109Lb,c Jupiter/Saturn Analog Planetary System
• Spitzer as Microlens Parallax Satellite: Mass Measurement for the OGLE-2014-BLG-0124L Planet and its Host Star
• Planet Parameters in Microlensing Events
• Systematic Analysis of 22 Microlensing Parallax Candidates
• Microlensing with advanced contour integration algorithm: Green's theorem to third order, error control, optimal sampling and limb darkening
• Acceleration and Parallax Effects in Gravitational Microlensing
• Pathway to the Galactic Distribution of Planets: Combined Spitzer and Ground-Based Microlens Parallax Measurements of 21 Single-Lens Events
• The First Circumbinary Planet Found by Microlensing: OGLE-2007-BLG-349L(AB)c
• Spitzer Parallax of OGLE-2015-BLG-0966: A Cold Neptune in the Galactic Disk
• Criteria for Sample Selection to Maximize Planet Sensitivity and Yield from Space-Based Microlens Parallax Surveys
• First Space-based Microlens Parallax Measurement of an Isolated Star: Spitzer Observations of OGLE-2014-BLG-0939
• Mass Measurements of Isolated Objects from Space-based Microlensing
• Spitzer as Microlens Parallax Satellite: Mass and Distance Measurements of Binary Lens System OGLE-2014-BLG-1050L
• Spitzer Microlens Measurement of a Massive Remnant in a Well-Separated Binary
• Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events
• OGLE-2015-BLG-0479LA,B: Binary Gravitational Microlens Characterized by Simultaneous Ground-based and Space-based Observation
• Two Stars Two Ways: Confirming a Microlensing Binary Lens Solution with a Spectroscopic Measurement of the Orbit
• OGLE-2015-BLG-0196: Ground-based Gravitational Microlens Parallax Confirmed By Space-Based Observation
• The first radial velocity measurements of a microlensing event: no evidence for the predicted binary
• Spectroscopic characterisation of microlensing events Towards a new interpretation of OGLE-2011-BLG-0417

Cited by in corpus (5)

• Measurement of Source Star Colors with the K2C9-CFHT Multi-color Microlensing Survey
• OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing
• OGLE-2016-BLG-1045: A Test of Cheap Space-Based Microlens Parallaxes
• Evidence of Systematic Errors in $Spitzer$ Microlens Parallax Measurements
• OGLE-2017-BLG-0329L: A Microlensing Binary Characterized with Dramatically Enhanced Precision Using Data from Space-based Observations