학술논문
A possible binary system of a stellar remnant in the high magnification gravitational microlensing event OGLE-2007-BLG-514
Document Type
Working Paper
Author
Miyake, N.; Udalski, A.; Sumi, T.; Bennett, D. P.; Dong, S.; Street, R. A.; Greenhill, J.; Bond, I. A.; Gould, A.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Ulaczyk, K.; Wyrzykowski, L.; Abe, F.; Fukui, A.; Furusawa, K.; Holderness, S.; Itow, Y.; Korpela, A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagayama, T.; Ohnishi, K.; Rattenbury, N.; Saito, To.; Sako, T.; Sullivan, D. J.; Sweatman, W. L.; Tristram, P. J.; Yock, P. C. M.; Allen, W.; Christie, G. W.; DePoy, D. L.; Gaudi, B. S.; Han, C.; Lee, C. -U.; McCormick, J.; Monard, B.; Natusch, T.; Park, B. -G.; Pogge, R. W.; Allan, A.; Bode, M.; Bramich, D. M.; Clay, N.; Dominik, M.; Horne, K. D.; Kains, N.; Mottram, C.; Snodgrass, C.; Steele, I.; Tsapras, Y.; Albrow, M. D.; Batista, V.; Beaulieu, J. P.; Brillant, S.; Burgdorf, M.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Cook, K. H.; Coutures, Ch.; Dieters, S.; Prester, D. Dominis; Donatowicz, J.; Fouque, P.; Jorgensen, U. G.; Kane, S.; Kubas, D.; Marquette, J. B.; Martin, R.; Menzies, J.; Pollard, K. R.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.
Source
Subject
Language
Abstract
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 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.
Comment: 31 pages, 6 figures, 7 tables, accepted in ApJ
Comment: 31 pages, 6 figures, 7 tables, accepted in ApJ