Asteroidscomets

Mass Measurements of Isolated Objects from Space-based Microlensing

July 2016 • 2016ApJ...825...60Z

Authors • Zhu, Wei • Calchi Novati, S. • Gould, A. • Udalski, A. • Han, C. • Shvartzvald, Y. • Ranc, C. • Jørgensen, U. G. • Poleski, R. • Bozza, V. • Beichman, C. • Bryden, G. • Carey, S. • Gaudi, B. S. • Henderson, C. B. • Pogge, R. W. • Porritt, I. • Wibking, B. • Yee, J. C. • SPITZER Team • Pawlak, M. • Szymański, M. K. • Skowron, J. • Mróz, P. • Kozłowski, S. • Wyrzykowski, Ł. • Pietrukowicz, P. • Pietrzyński, G. • Soszyński, I. • Ulaczyk, K. • OGLE Group • 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. • KMTNET Group • Friedmann, M. • Kaspi, S. • Maoz, D. • WISE Group • Hundertmark, M. • Street, R. A. • Tsapras, Y. • Bramich, D. M. • Cassan, A. • Dominik, M. • Bachelet, E. • Dong, Subo • Figuera Jaimes, R. • Horne, K. • Mao, S. • Menzies, J. • Schmidt, R. • Snodgrass, C. • Steele, I. A. • Wambsganss, J. • RoboNeT Team • Skottfelt, J. • Andersen, M. I. • Burgdorf, M. J. • Ciceri, S. • D'Ago, G. • Evans, D. F. • Gu, S. -H. • Hinse, T. C. • Kerins, E. • Korhonen, H. • Kuffmeier, M. • Mancini, L. • Peixinho, N. • Popovas, A. • Rabus, M. • Rahvar, S. • Tronsgaard, R. • Scarpetta, G. • Southworth, J. • Surdej, J. • von Essen, C. • Wang, Y. -B. • Wertz, O. • MiNDSTEP Group

Abstract • We report on the mass and distance measurements of two single-lens events from the 2015 Spitzer microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is very likely a brown dwarf (BD). Assuming that the source star lies behind the same amount of dust as the Bulge red clump, we find the lens is a 45 ± 7 {M}{{J}} BD at 5.9 ± 1.0 kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a 0.50 ± 0.04 {M} star at 6.9 ± 1.0 kpc. We show that the probability to definitively measure the mass of isolated microlenses is dramatically increased once simultaneous ground- and space-based observations are conducted.

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IPAC Authors
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Fotina

Sebastiano Calchi Novati

Associate Scientist


Sean Carey

Senior Scientist