Spitzer microlens measurement of a massive remnant in a well-separated binary
MetadataShow full item record
We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M1 > 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.
Shvartzvald , Y , Udalski , A , Gould , A , Han , C , Bozza , V , Friedmann , M , Hundertmark , M P G , Beichman , C , Bryden , G , Novati , S C , Carey , S , Fausnaugh , M , Gaudi , B S , Henderson , C B , Kerr , T , Pogge , R W , Varricatt , W , Wibking , B , Yee , J C , Zhu , W , Poleski , R , Pawlak , M , Szymański , M K , Skowron , J , Mróz , P , Kozłowski , S , Wyrzykowski , Ł , Pietrukowicz , P , Pietrzyński , G , Soszyński , I , Ulaczyk , K , Choi , J-Y , Park , H , Jung , Y K , Shin , I-G , Albrow , M D , Park , B-G , Kim , S-L , Lee , C-U , Cha , S-M , Kim , D-J , Lee , Y , Maoz , D , Kaspi , S , Street , R A , Tsapras , Y , Bachelet , E , Dominik , M , Bramich , D M , Horne , K D , Snodgrass , C , Steele , I A , Menzies , J , Figuera Jaimes , R J , Wambsganss , J , Schmidt , R , Cassan , A , Ranc , C , Mao , S , Dong , S , D’Ago , G , Scarpetta , G , Verma , P , Jørgensen , U G , Kerins , E & Skottfelt , J 2015 , ' Spitzer microlens measurement of a massive remnant in a well-separated binary ' , Astrophysical Journal , vol. 814 , no. 2 , pp. 111 . https://doi.org/10.1088/0004-637X/814/2/111
© 2015. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at http://dx.doi.org/10.1088/0004-637X/814/2/111.