Naslov
A Possible Binary System of a Stellar Remnant in the High-magnification Gravitational Microlensing Event OGLE-2007-BLG-514

Autori
Miyake, N ; ... ; Dominis Prester, Dijana ; ... ; ... ; Zub, M.

Izvornik
The Astrophysical journal (0004-637X) 752 (2012), 2; 82-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
binaries: general; Galaxy: bulge; gravitational lensing: micro

Sažetak
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 ± 0.39 kpc and total mass ML = 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+4.6 -0.3 M sun and it is at a distance of D L = 2.6+3.8 -0.9 kpc. Given the secure mass ratio measurement, the companion mass is therefore M 2 = 0.2+1.2 -0.1 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

Napomena
The PLANET Collaboration.

POVEZANOST RADA