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A possible binary system of a stellar remnant in the high-magnification gravitational microlensing event OGLE-2007-BLG-514


Miyake, N and Udalski, A and Sumi, T and Bennett, DP and Dong, S and Street, RA and Greenhill, J and Bond, IA and Gould, A and Kubiak, M and Szymanski, MK and Pietrzynski, G and Soszynski, I and Ulaczyk, K and Wyrzykowski, L and Abe, F and Fukui, A and Furusawa, K and Holderness, S and Itow, Y and Korpela, A and Ling, CH and Masuda, K and Matsubara, Y and Muraki, Y and Nagayama, T and Ohnishi, K and Rattenbury, N and Saito, T and Sako, T and Sullivan, DJ and Sweatman, WL and Tristram, PJ and Yock, PCM and Allen, W and Christie, GW and Depoy, DL and Gaudi, BS and Han, C and Lee, C-U and McCormick, J and Monard, B and Natusch, T and Park, B-G and Pogge, RW and Allan, A and Bode, M and Bramich, DM and Clay, N and Dominik, M and Horne, KD and Kains, N and Mottram, C and Snodgrass, C and Steele, I and Tsapras, Y and Albrow, MD and Batista, V and Beaulieu, JP and Brillant, S and Burgdorf, M and Caldwell, JAR and Cassan, A and Cole, A and Cook, KH and Coutures, C and Dieters, S and Prester, DD and Donatowicz, J and Fouque, P and Jorgensen, UG and Kane, S and Kubas, D and Marquette, JB and Martin, R and Menzies, J and Pollard, KR and Sahu, KC and Wambsganss, J and Williams, A and Zub, M, A possible binary system of a stellar remnant in the high-magnification gravitational microlensing event OGLE-2007-BLG-514, Astrophysical Journal, 752, (2) Article 82. ISSN 0004-637X (2012) [Refereed Article]

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Copyright 2012 The American Astronomical Society

DOI: doi:10.1088/0004-637X/752/2/82


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 M1 = 1.06 ± 0.13 M⊙ and M2 = 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 M1 = 0.9+4.6-0.3 M⊙ and it is at a distance of DL = 2.6+3.8-0.9 kpc. Given the secure mass ratio measurement, the companion mass is therefore M2 = 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.

Item Details

Item Type:Refereed Article
Keywords:binaries: general; Galaxy: bulge; gravitational lensing: micro
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Stellar astronomy and planetary systems
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Greenhill, J (Dr John Greenhill)
UTAS Author:Cole, A (Associate Professor Andrew Cole)
ID Code:79940
Year Published:2012
Web of Science® Times Cited:12
Deposited By:Mathematics and Physics
Deposited On:2012-10-15
Last Modified:2017-11-03

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