Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050
Creators: name: Batista, V.
name: Dong, Subo
name: Gould, A.
name: Beaulieu, J. P.
name: Cassan, A.
name: Christie, G. W.
name: Han, C.
name: Udalski, A.
name: Allen, W.
name: DePoy, D. L.
name: Gal-Yam, A.
name: Gaudi, B. S.
name: Johnson, B.
name: Kaspi, S.
name: Lee, C. U.
name: Maoz, D.
name: McCormick, J.
name: McGreer, I.
name: Monard, B.
name: Natusch, T.
name: Ofek, E.
name: Park, B. -G.
name: Pogge, R. W.
name: Polishook, D.
name: Shporer, A.
name: Albrow, M. D.
name: Bennett, D. P.
name: Brillant, S.
name: Bode, M.
name: Bramich, D. M.
name: Burgdorf, M.
name: Caldwell, J. A. R.
name: Calitz, H.
name: Cole, A.
name: Cook, K. H.
name: Coutures, Ch.
name: Dieters, S.
name: Dominik, M.
name: Prester, D. Dominis
name: Donatowicz, J.
name: Fouqué, P.
name: Greenhill, J.
name: Hoffman, M.
name: Horne, K.
name: Jørgensen, U. G.
name: Kains, N.
name: Kane, S.
name: Kubas, D.
name: Marquette, J. B.
name: Martin, R.
name: Meintjes, P.
name: Menzies, J.
name: Pollard, K. R.
name: Sahu, K. C.
name: Snodgrass, C.
name: Steele, I.
name: Tsapras, Y.
name: Wambsganss, J.
name: Williams, A.
name: Zub, M.
name: Wyrzykowski, Ł.
name: Kubiak, M.
name: Szymański, M. K.
name: Pietrzyński, G.
name: Soszyński, I.
name: Szewczyk, O.
name: Ulaczyk, K.
name: Abe, F.
name: Bond, I. A.
name: Fukui, A.
name: Furusawa, K.
name: Hearnshaw, J. B.
name: Holderness, S.
name: Itow, Y.
name: Kamiya, K.
name: Kilmartin, P. M.
name: Korpela, A.
name: Lin, W.
name: Ling, C. H.
name: Masuda, K.
name: Matsubara, Y.
name: Miyake, N.
name: Muraki, Y.
name: Nagaya, M.
name: Ohnishi, K.
name: Okumura, T.
name: Perrott, Y. C.
name: Rattenbury, N.
name: Saito, To.
name: Sako, T.
name: Skuljan, L.
name: Sullivan, D.
name: Sumi, T.
name: Sweatman, W. L.
name: Tristram, P. J.
name: Yock, P. C. M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A ~ 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to determine its sensitivity to the presence of planets around the lens star. Both finite-source and parallax effects permit a measurement of the angular Einstein radius θ_E = 0.48 +/- 0.01 mas and the parallax π_E = 0.12 +/- 0.03, leading to an estimate of the lens mass M = 0.50 +/- 0.14 M_Sun and its distance to the observer D_L = 5.5 +/- 0.4 kpc. This is only the second determination of a reasonably precise (&lt;30%) mass estimate for an isolated unseen object, using any method. This allows us to calculate the planetary detection efficiency in physical units (r_\perp, m_p), where r_\perp is the projected planet-star separation and m_p is the planet mass. When computing planet detection efficiency, we did not find any planetary signature and our detection efficiency results reveal significant sensitivity to Neptune-mass planets, and to a lesser extent Earth-mass planets in some configurations. Indeed, Jupiter and Neptune-mass planets are excluded with a high confidence for a large projected separation range between the planet and the lens star, respectively [0.6 - 10] and [1.4 - 4] AU, and Earth-mass planets are excluded with a 10% confidence in the lensing zone, i.e. [1.8 - 3.1] AU.
description: 20 pages, 23 figures