A possible binary system of a stellar remnant in the high magnification gravitational microlensing event OGLE-2007-BLG-514
Creators: name: Miyake, N.
name: Udalski, A.
name: Sumi, T.
name: Bennett, D. P.
name: Dong, S.
name: Street, R. A.
name: Greenhill, J.
name: Bond, I. A.
name: Gould, A.
name: Kubiak, M.
name: Szymanski, M. K.
name: Pietrzynski, G.
name: Soszynski, I.
name: Ulaczyk, K.
name: Wyrzykowski, L.
name: Abe, F.
name: Fukui, A.
name: Furusawa, K.
name: Holderness, S.
name: Itow, Y.
name: Korpela, A.
name: Ling, C. H.
name: Masuda, K.
name: Matsubara, Y.
name: Muraki, Y.
name: Nagayama, T.
name: Ohnishi, K.
name: Rattenbury, N.
name: Saito, To.
name: Sako, T.
name: Sullivan, D. J.
name: Sweatman, W. L.
name: Tristram, P. J.
name: Yock, P. C. M.
name: Allen, W.
name: Christie, G. W.
name: DePoy, D. L.
name: Gaudi, B. S.
name: Han, C.
name: Lee, C. -U.
name: McCormick, J.
name: Monard, B.
name: Natusch, T.
name: Park, B. -G.
name: Pogge, R. W.
name: Allan, A.
name: Bode, M.
name: Bramich, D. M.
name: Clay, N.
name: Dominik, M.
name: Horne, K. D.
name: Kains, N.
name: Mottram, C.
name: Snodgrass, C.
name: Steele, I.
name: Tsapras, Y.
name: Albrow, M. D.
name: Batista, V.
name: Beaulieu, J. P.
name: Brillant, S.
name: Burgdorf, M.
name: Caldwell, J. A. R.
name: Cassan, A.
name: Cole, A.
name: Cook, K. H.
name: Coutures, Ch.
name: Dieters, S.
name: Prester, D. Dominis
name: Donatowicz, J.
name: Fouque, P.
name: Jorgensen, U. G.
name: Kane, S.
name: Kubas, D.
name: Marquette, J. B.
name: Martin, R.
name: Menzies, J.
name: Pollard, K. R.
name: Sahu, K. C.
name: Wambsganss, J.
name: Williams, A.
name: Zub, M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the extremely high magnification (A &gt; 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 +/- 0.007 and a projected separation of s = 0.072 +/- 0.001$ in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D_L = 3.11 +/- 0.39 kpc and total mass M_L=1.40 +/- 0.18 M_sun; this leads to the primary and secondary components having masses of M_1 = 1.06 +/- 0.13 M_sun and M_2 = 0.34 +/- 0.04 M_sun, respectively. The parallax model indicates that the binary lens system is likely constructed by the main sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 +/- 0.005, s = 0.083 +/- 0.001). The primary component of the binary lens is relatively massive with M_1 = 0.9_{-0.3}^{+4.6} M_sun and it is at a distance of D_L = 2.6_{-0.9}^{+3.8} kpc. Given the secure mass ratio measurement, the companion mass is therefore M_2 = 0.2_{-0.1}^{+1.2} M_sun. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star or a black hole.
description: 31 pages, 6 figures, 7 tables, accepted in ApJ