TY - JOUR
T1 - A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514
AU - Miyake, N.
AU - Udalski, A.
AU - Sumi, T.
AU - Bennett, D.P.
AU - Song, S.
AU - Dong, S.
AU - Street, R.A.
AU - Greenhill, J.
AU - Bond, I.A.
AU - Gould, A.
AU - Kubiak, M.
AU - Jørgensen, Uffe Gråe
PY - 2012/6/20
Y1 - 2012/6/20
N2 - We report the extremely high-magnification (A > 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 DL = 3.11 ± 0.39kpc and total mass ML = 1.40 ± 0.18 M ⊙; this leads to the primary and secondary components having masses of M 1 = 1.06 ± 0.13 M ⊙ and M 2 = 0.34 ± 0.04 M ⊙, 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+4.6 -0.3 M ⊙ and it is at a distance of D L = 2.6+3.8 -0.9kpc. Given the secure mass ratio measurement, the companion mass is therefore M 2 = 0.2+1.2 -0.1 M ⊙. 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.
AB - We report the extremely high-magnification (A > 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 DL = 3.11 ± 0.39kpc and total mass ML = 1.40 ± 0.18 M ⊙; this leads to the primary and secondary components having masses of M 1 = 1.06 ± 0.13 M ⊙ and M 2 = 0.34 ± 0.04 M ⊙, 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+4.6 -0.3 M ⊙ and it is at a distance of D L = 2.6+3.8 -0.9kpc. Given the secure mass ratio measurement, the companion mass is therefore M 2 = 0.2+1.2 -0.1 M ⊙. 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.
U2 - 10.1088/0004-637X/752/2/82
DO - 10.1088/0004-637X/752/2/82
M3 - Journal article
SN - 0004-637X
VL - 752
SP - 82
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -