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Spitzer Microlens Measurement of a Massive Remnant in a Well-Separated Binary

Shvartzvald, Y. and Beichman, C. and Calchi Novati, S. and Carey, S. (2015) Spitzer Microlens Measurement of a Massive Remnant in a Well-Separated Binary. Astrophysical Journal, 814 (2). Art. No. 111. ISSN 0004-637X.

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We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M_1 > 1.35 M_⊙ (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r_⊥ = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the "microlens parallax" effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay at 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Shvartzvald, Y.0000-0003-1525-5041
Beichman, C.0000-0002-5627-5471
Calchi Novati, S.0000-0002-7669-1069
Carey, S.0000-0002-0221-6871
Additional Information:© 2015 American Astronomical Society. Received 2015 August 25; accepted 2015 October 21; published 2015 November 23. Work by Y.S. was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, administered by Oak Ridge Associated Universities through a contract with NASA. The OGLE project has received funding from the National Science Centre, Poland, grant MAESTRO 2014/14/A/ST9/00121 to AU. Work by J.C.Y., A.G., and S.C. was supported by JPL grant 1500811. Work by J.C.Y. was performed under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. Work by C.H. was supported by Creative Research Initiative Program (2009-0081561) of National Research Foundation of Korea. This research has made the telescopes of KMTNet operated by the Korea Astronomy and Space Science Institute (KASI). L.W. acknowledges support from the Polish NCN Harmonia grant No. 2012/06/M/ST9/00172. D.M. and A.G. acknowledge support by a grant from the US Israel Binational Science Foundation. Work by D.M. is supported by the I-CORE program of the Israel Science Foundation and the Planning and Budgeting Committee. This publication was made possible by NPRP grant # X-019-1-006 from the Qatar National Research Fund (a member of Qatar Foundation) S.D. is supported by "the Strategic Priority Research Program—The Emergence of Cosmological Structures" of the Chinese Academy of Sciences (grant No. XDB09000000). Work by S.M. has been supported by the Strategic Priority Research Program "The Emergence of Cosmological Structures" of the Chinese Academy of Sciences Grant No. XDB09000000, and by the National Natural Science Foundation of China (NSFC) under grant numbers 11333003 and 11390372. M.P.G.H. acknowledges support from the Villum Foundation. Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla observatory. 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. The United Kingdom Infrared Telescope (UKIRT) is supported by NASA and operated under an agreement among the University of Hawaii, the University of Arizona, and Lockheed Martin Advanced Technology Center; operations are enabled through the cooperation of the Joint Astronomy Centre of the Science and Technology Facilities Council of the U.K. This work makes use of observations from the LCOGT network, which includes three SUPAscopes owned by the University of St Andrews. The RoboNet programme is an LCOGT Key Project using time allocations from the University of St Andrews, LCOGT, and the University of Heidelberg together with time on the Liverpool Telescope through the Science and Technology Facilities Council (STFC), UK. This research has made use of the LCOGT Archive, which is operated by the California Institute of Technology, under contract with the Las Cumbres Observatory. The Spitzer Team thanks Christopher S. Kochanek for graciously trading us his allocated observing time on the CTIO 1.3 m during the Spitzer campaign.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
National Science Centre (Poland)MAESTRO 2014/14/A/ST9/00121
National Research Foundation of Korea2009-008561
National Science Centre (Poland)2012/06/M/ST9/00172
Binational Science Foundation (USA-Israel)UNSPECIFIED
Planning and Budgeting Committee I-CORE ProgramUNSPECIFIED
Qatar National Research FundX-019-1-006
Chinese Academy of SciencesXDB09000000
National Natural Science Foundation of China11333003
Villum FoundationUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Las Cumbres ObservatoryUNSPECIFIED
Subject Keywords:binaries: general; black hole physics; Galaxy: bulge; gravitational lensing: micro; stars: neutron
Issue or Number:2
Record Number:CaltechAUTHORS:20151222-151812262
Persistent URL:
Official Citation:Y. Shvartzvald et al 2015 ApJ 814 111
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63151
Deposited By: Ruth Sustaita
Deposited On:23 Dec 2015 18:57
Last Modified:24 Feb 2020 10:30

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