SPITZER MICROLENS MEASUREMENT OF A MASSIVE REMNANT IN A WELL-SEPARATED BINARY

Journal Article · Tue Dec 01 00:00:00 EST 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/814/2/111· OSTI ID:22521858

Shvartzvald, Y.; Bryden, G.; Henderson, C. B. ^[1]; Udalski, A. ^[2]; Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W. ^[3]; Han, C. ^[4]; Bozza, V.; Novati, S. Calchi ^[5]; Friedmann, M. ^[6]; Hundertmark, M. ^[7]; Beichman, C. ^[8]; Carey, S. ^[9]; Kerr, T.; Varricatt, W. ^[10]; Yee, J. C. ^[11] ; RoboNet,; MiNDSTEp,; others, and

---

1. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
2. Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)
3. Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States)
4. Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)
5. Dipartimento di Fisica “E. R. Caianiello,” Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano (Italy)
6. School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel)
7. Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K (Denmark)
8. NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)
9. Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States)
10. UKIRT, 660 N. Aohoku Place, University Park, Hilo, HI 96720 (United States)
11. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M{sub 1} > 1.35 M{sub ⊙} (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{sub ⊥} = 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.

• OSTI ID: 22521858
• Journal Information: Astrophysical Journal, Vol. 814, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BLACK HOLES
COMPARATIVE EVALUATIONS
DETECTION
DIAGRAMS
GALAXIES
GRAVITATIONAL LENSES
MAIN SEQUENCE STARS
MASS
NEAR INFRARED RADIATION
NEUTRON STARS
TELESCOPES
VISIBLE RADIATION