CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS

J. -Y. Choi; I. -G. Shin; S. -Y. Park; C. Han; A. Gould; T. Sumi; A. Udalski; J. -P. Beaulieu; R. Street; M. Dominik; W. Allen; L. A. Almeida; M. Bos; G. W. Christie; D. L. Depoy; S. Dong; J. Drummond; A. Gal-Yam; B. S. Gaudi; C. B. Henderson; L. -W. Hung; F. Jablonski; J. Janczak; C. -U. Lee; F. Mallia; A. Maury; J. McCormick; D. McGregor; L. A. G. Monard; D. Moorhouse; J. A. Munoz; T. Natusch; C. Nelson; B. -G. Park; R. W. Pogge; T. -G. "TG" Tan; G. Thornley; J. C. Yee; F. Abe; E. Barnard; J. Baudry; D. P. Bennett; I. A. Bond; C. S. Botzler; M. Freeman; A. Fukui; K. Furusawa; F. Hayashi; J. B. Hearnshaw; S. Hosaka; Y. Itow; K. Kamiya; P. M. Kilmartin; S. Kobara; A. Korpela; W. Lin; C. H. Ling; S. Makita; K. Masuda; Y. Matsubara; N. Miyake; Y. Muraki; M. Nagaya; K. Nishimoto; K. Ohnishi; T. Okumura; K. Omori; Y. C. Perrott; N. Rattenbury; To Saito; L. Skuljan; D. J. Sullivan; D. Suzuki; K. Suzuki; W. L. Sweatman; S. Takino; P. J. Tristram; K. Wada; P. C. M. Yock; M. K. Szymanski; M. Kubiak; G. Pietrzynski; I. Soszynski; R. Poleski; K. Ulaczyk; L. Wyrzykowski; S. Kozllowski; P. Pietrukowicz; M. D. Albrow; E. Bachelet; V. Batista; C. S. Bennett; R. Bowens-Rubin; S. Brillant; A. Cassan; A. Cole; E. Corrales; Ch. Coutures; S. Dieters; D. Dominis Prester; J. Donatowicz; P. Fouque; J. Greenhill; S. R. Kane; J. Menzies; K. C. Sahu; J. Wambsganss; A. Williams; M. Zub; A. Allan; D. M. Bramich; P. Browne; N. Clay; S. Fraser; K. Horne; N. Kains; C. Mottram; C. Snodgrass; I. Steele; Y. Tsapras; K. A. Alsubai; V. Bozza; M. J. Burgdorf; S. Calchi Novati; P. Dodds; S. Dreizler; F. Finet; T. Gerner; M. Glitrup; F. Grundahl; S. Hardis; K. Harpsoe; T. C. Hinse; M. Hundertmark; U. G. Jorgensen; E. Kerins; C. Liebig; G. Maier; L. Mancini; M. Mathiasen; M. T. Penny; S. Proft; S. Rahvar; D. Ricci; G. Scarpetta; S. Schaefer; F. Schoenebeck; J. Skottfelt; J. Surdej; J. Southworth; F. Zimmer

doi:10.1088/0004-637X/751/1/41

CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS

J. -Y. Choi, I. -G. Shin, S. -Y. Park, C. Han^*, A. Gould, T. Sumi, A. Udalski, J. -P. Beaulieu, R. Street, M. Dominik, W. Allen, L. A. Almeida, M. Bos, G. W. Christie, D. L. Depoy, S. Dong, J. Drummond, A. Gal-Yam, B. S. Gaudi, C. B. HendersonL. -W. Hung, F. Jablonski, J. Janczak, C. -U. Lee, F. Mallia, A. Maury, J. McCormick, D. McGregor, L. A. G. Monard, D. Moorhouse, J. A. Munoz, T. Natusch, C. Nelson, B. -G. Park, R. W. Pogge, T. -G. "TG" Tan, G. Thornley, J. C. Yee, F. Abe, E. Barnard, J. Baudry, D. P. Bennett, I. A. Bond, C. S. Botzler, M. Freeman, A. Fukui, K. Furusawa, F. Hayashi, J. B. Hearnshaw, S. Hosaka, Y. Itow, K. Kamiya, P. M. Kilmartin, S. Kobara, A. Korpela, W. Lin, C. H. Ling, S. Makita, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, M. Nagaya, K. Nishimoto, K. Ohnishi, T. Okumura, K. Omori, Y. C. Perrott, N. Rattenbury, To Saito, L. Skuljan, D. J. Sullivan, D. Suzuki, K. Suzuki, W. L. Sweatman, S. Takino, P. J. Tristram, K. Wada, P. C. M. Yock, M. K. Szymanski, M. Kubiak, G. Pietrzynski, I. Soszynski, R. Poleski, K. Ulaczyk, L. Wyrzykowski, S. Kozllowski, P. Pietrukowicz, M. D. Albrow, E. Bachelet, V. Batista, C. S. Bennett, R. Bowens-Rubin, S. Brillant, A. Cassan, A. Cole, E. Corrales, Ch. Coutures, S. Dieters, D. Dominis Prester, J. Donatowicz, P. Fouque, J. Greenhill, S. R. Kane, J. Menzies, K. C. Sahu, J. Wambsganss, A. Williams, M. Zub, A. Allan, D. M. Bramich, P. Browne, N. Clay, S. Fraser, K. Horne, N. Kains, C. Mottram, C. Snodgrass, I. Steele, Y. Tsapras, K. A. Alsubai, V. Bozza, M. J. Burgdorf, S. Calchi Novati, P. Dodds, S. Dreizler, F. Finet, T. Gerner, M. Glitrup, F. Grundahl, S. Hardis, K. Harpsoe, T. C. Hinse, M. Hundertmark, U. G. Jorgensen, E. Kerins, C. Liebig, G. Maier, L. Mancini, M. Mathiasen, M. T. Penny, S. Proft, S. Rahvar, D. Ricci, G. Scarpetta, S. Schaefer, F. Schoenebeck, J. Skottfelt, J. Surdej, J. Southworth, F. Zimmer

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

28 Citations (Scopus)

Abstract

We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of theta(E) similar to 0.08 mas combined with the short timescale of t(E) similar to 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of similar to 0.84M(circle dot) is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.

Original language	English
Article number	41
Number of pages	14
Journal	Astrophysical Journal
Volume	751
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/751/1/41
Publication status	Published - 20 May 2012

Keywords

Galaxy: bulge
gravitational lensing: micro
STELLAR ATMOSPHERE MODELS
GALACTIC BULGE
LIGHT CURVES
CHEMICAL EVOLUTION
DWARF
PHOTOMETRY
PLANETS
GIANT
SIGNATURES
SYSTEMS

Access to Document

10.1088/0004-637X/751/1/41

Astrophysics at St Andrews:2012 - 2014: Astrophysics at St Andrews: 2012 - 2014
Horne, K. D. (PI)
Science & Technology Facilities Council
1/10/11 → 31/03/12
Project: Standard

Cite this

Choi, J. .-Y., Shin, I. .-G., Park, S. .-Y., Han, C., Gould, A., Sumi, T., Udalski, A., Beaulieu, J. .-P., Street, R., Dominik, M., Allen, W., Almeida, L. A., Bos, M., Christie, G. W., Depoy, D. L., Dong, S., Drummond, J., Gal-Yam, A., Gaudi, B. S., ... Zimmer, F. (2012). CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS. Astrophysical Journal, 751(1), Article 41. https://doi.org/10.1088/0004-637X/751/1/41

@article{226322acdc8545169bd45ce500de9453,

title = "CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS",

abstract = "We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of theta(E) similar to 0.08 mas combined with the short timescale of t(E) similar to 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of similar to 0.84M(circle dot) is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.",

keywords = "Galaxy: bulge, gravitational lensing: micro, STELLAR ATMOSPHERE MODELS, GALACTIC BULGE, LIGHT CURVES, CHEMICAL EVOLUTION, DWARF, PHOTOMETRY, PLANETS, GIANT, SIGNATURES, SYSTEMS",

author = "Choi, {J. -Y.} and Shin, {I. -G.} and Park, {S. -Y.} and C. Han and A. Gould and T. Sumi and A. Udalski and Beaulieu, {J. -P.} and R. Street and M. Dominik and W. Allen and Almeida, {L. A.} and M. Bos and Christie, {G. W.} and Depoy, {D. L.} and S. Dong and J. Drummond and A. Gal-Yam and Gaudi, {B. S.} and Henderson, {C. B.} and Hung, {L. -W.} and F. Jablonski and J. Janczak and Lee, {C. -U.} and F. Mallia and A. Maury and J. McCormick and D. McGregor and Monard, {L. A. G.} and D. Moorhouse and Munoz, {J. A.} and T. Natusch and C. Nelson and Park, {B. -G.} and Pogge, {R. W.} and Tan, {T. -G. {"}TG{"}} and G. Thornley and Yee, {J. C.} and F. Abe and E. Barnard and J. Baudry and Bennett, {D. P.} and Bond, {I. A.} and Botzler, {C. S.} and M. Freeman and A. Fukui and K. Furusawa and F. Hayashi and Hearnshaw, {J. B.} and S. Hosaka and Y. Itow and K. Kamiya and Kilmartin, {P. M.} and S. Kobara and A. Korpela and W. Lin and Ling, {C. H.} and S. Makita and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and M. Nagaya and K. Nishimoto and K. Ohnishi and T. Okumura and K. Omori and Perrott, {Y. C.} and N. Rattenbury and To Saito and L. Skuljan and Sullivan, {D. J.} and D. Suzuki and K. Suzuki and Sweatman, {W. L.} and S. Takino and Tristram, {P. J.} and K. Wada and Yock, {P. C. M.} and Szymanski, {M. K.} and M. Kubiak and G. Pietrzynski and I. Soszynski and R. Poleski and K. Ulaczyk and L. Wyrzykowski and S. Kozllowski and P. Pietrukowicz and Albrow, {M. D.} and E. Bachelet and V. Batista and Bennett, {C. S.} and R. Bowens-Rubin and S. Brillant and A. Cassan and A. Cole and E. Corrales and Ch. Coutures and S. Dieters and Prester, {D. Dominis} and J. Donatowicz and P. Fouque and J. Greenhill and Kane, {S. R.} and J. Menzies and Sahu, {K. C.} and J. Wambsganss and A. Williams and M. Zub and A. Allan and Bramich, {D. M.} and P. Browne and N. Clay and S. Fraser and K. Horne and N. Kains and C. Mottram and C. Snodgrass and I. Steele and Y. Tsapras and Alsubai, {K. A.} and V. Bozza and Burgdorf, {M. J.} and {Calchi Novati}, S. and P. Dodds and S. Dreizler and F. Finet and T. Gerner and M. Glitrup and F. Grundahl and S. Hardis and K. Harpsoe and Hinse, {T. C.} and M. Hundertmark and Jorgensen, {U. G.} and E. Kerins and C. Liebig and G. Maier and L. Mancini and M. Mathiasen and Penny, {M. T.} and S. Proft and S. Rahvar and D. Ricci and G. Scarpetta and S. Schaefer and F. Schoenebeck and J. Skottfelt and J. Surdej and J. Southworth and F. Zimmer",

year = "2012",

month = may,

day = "20",

doi = "10.1088/0004-637X/751/1/41",

language = "English",

volume = "751",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

Choi, J-Y, Shin, I-G, Park, S-Y, Han, C, Gould, A, Sumi, T, Udalski, A, Beaulieu, J-P, Street, R, Dominik, M, Allen, W, Almeida, LA, Bos, M, Christie, GW, Depoy, DL, Dong, S, Drummond, J, Gal-Yam, A, Gaudi, BS, Henderson, CB, Hung, L-W, Jablonski, F, Janczak, J, Lee, C-U, Mallia, F, Maury, A, McCormick, J, McGregor, D, Monard, LAG, Moorhouse, D, Munoz, JA, Natusch, T, Nelson, C, Park, B-G, Pogge, RW, Tan, T-G, Thornley, G, Yee, JC, Abe, F, Barnard, E, Baudry, J, Bennett, DP, Bond, IA, Botzler, CS, Freeman, M, Fukui, A, Furusawa, K, Hayashi, F, Hearnshaw, JB, Hosaka, S, Itow, Y, Kamiya, K, Kilmartin, PM, Kobara, S, Korpela, A, Lin, W, Ling, CH, Makita, S, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Nagaya, M, Nishimoto, K, Ohnishi, K, Okumura, T, Omori, K, Perrott, YC, Rattenbury, N, Saito, T, Skuljan, L, Sullivan, DJ, Suzuki, D, Suzuki, K, Sweatman, WL, Takino, S, Tristram, PJ, Wada, K, Yock, PCM, Szymanski, MK, Kubiak, M, Pietrzynski, G, Soszynski, I, Poleski, R, Ulaczyk, K, Wyrzykowski, L, Kozllowski, S, Pietrukowicz, P, Albrow, MD, Bachelet, E, Batista, V, Bennett, CS, Bowens-Rubin, R, Brillant, S, Cassan, A, Cole, A, Corrales, E, Coutures, C, Dieters, S, Prester, DD, Donatowicz, J, Fouque, P, Greenhill, J, Kane, SR, Menzies, J, Sahu, KC, Wambsganss, J, Williams, A, Zub, M, Allan, A, Bramich, DM, Browne, P, Clay, N, Fraser, S, Horne, K, Kains, N, Mottram, C, Snodgrass, C, Steele, I, Tsapras, Y, Alsubai, KA, Bozza, V, Burgdorf, MJ, Calchi Novati, S, Dodds, P, Dreizler, S, Finet, F, Gerner, T, Glitrup, M, Grundahl, F, Hardis, S, Harpsoe, K, Hinse, TC, Hundertmark, M, Jorgensen, UG, Kerins, E, Liebig, C, Maier, G, Mancini, L, Mathiasen, M, Penny, MT, Proft, S, Rahvar, S, Ricci, D, Scarpetta, G, Schaefer, S, Schoenebeck, F, Skottfelt, J, Surdej, J, Southworth, J & Zimmer, F 2012, 'CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS', Astrophysical Journal, vol. 751, no. 1, 41. https://doi.org/10.1088/0004-637X/751/1/41

TY - JOUR

T1 - CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS

AU - Choi, J. -Y.

AU - Shin, I. -G.

AU - Park, S. -Y.

AU - Han, C.

AU - Gould, A.

AU - Sumi, T.

AU - Udalski, A.

AU - Beaulieu, J. -P.

AU - Street, R.

AU - Dominik, M.

AU - Allen, W.

AU - Almeida, L. A.

AU - Bos, M.

AU - Christie, G. W.

AU - Depoy, D. L.

AU - Dong, S.

AU - Drummond, J.

AU - Gal-Yam, A.

AU - Gaudi, B. S.

AU - Henderson, C. B.

AU - Hung, L. -W.

AU - Jablonski, F.

AU - Janczak, J.

AU - Lee, C. -U.

AU - Mallia, F.

AU - Maury, A.

AU - McCormick, J.

AU - McGregor, D.

AU - Monard, L. A. G.

AU - Moorhouse, D.

AU - Munoz, J. A.

AU - Natusch, T.

AU - Nelson, C.

AU - Park, B. -G.

AU - Pogge, R. W.

AU - Tan, T. -G. "TG"

AU - Thornley, G.

AU - Yee, J. C.

AU - Abe, F.

AU - Barnard, E.

AU - Baudry, J.

AU - Bennett, D. P.

AU - Bond, I. A.

AU - Botzler, C. S.

AU - Freeman, M.

AU - Fukui, A.

AU - Furusawa, K.

AU - Hayashi, F.

AU - Hearnshaw, J. B.

AU - Hosaka, S.

AU - Itow, Y.

AU - Kamiya, K.

AU - Kilmartin, P. M.

AU - Kobara, S.

AU - Korpela, A.

AU - Lin, W.

AU - Ling, C. H.

AU - Makita, S.

AU - Masuda, K.

AU - Matsubara, Y.

AU - Miyake, N.

AU - Muraki, Y.

AU - Nagaya, M.

AU - Nishimoto, K.

AU - Ohnishi, K.

AU - Okumura, T.

AU - Omori, K.

AU - Perrott, Y. C.

AU - Rattenbury, N.

AU - Saito, To

AU - Skuljan, L.

AU - Sullivan, D. J.

AU - Suzuki, D.

AU - Suzuki, K.

AU - Sweatman, W. L.

AU - Takino, S.

AU - Tristram, P. J.

AU - Wada, K.

AU - Yock, P. C. M.

AU - Szymanski, M. K.

AU - Kubiak, M.

AU - Pietrzynski, G.

AU - Soszynski, I.

AU - Poleski, R.

AU - Ulaczyk, K.

AU - Wyrzykowski, L.

AU - Kozllowski, S.

AU - Pietrukowicz, P.

AU - Albrow, M. D.

AU - Bachelet, E.

AU - Batista, V.

AU - Bennett, C. S.

AU - Bowens-Rubin, R.

AU - Brillant, S.

AU - Cassan, A.

AU - Cole, A.

AU - Corrales, E.

AU - Coutures, Ch.

AU - Dieters, S.

AU - Prester, D. Dominis

AU - Donatowicz, J.

AU - Fouque, P.

AU - Greenhill, J.

AU - Kane, S. R.

AU - Menzies, J.

AU - Sahu, K. C.

AU - Wambsganss, J.

AU - Williams, A.

AU - Zub, M.

AU - Allan, A.

AU - Bramich, D. M.

AU - Browne, P.

AU - Clay, N.

AU - Fraser, S.

AU - Horne, K.

AU - Kains, N.

AU - Mottram, C.

AU - Snodgrass, C.

AU - Steele, I.

AU - Tsapras, Y.

AU - Alsubai, K. A.

AU - Bozza, V.

AU - Burgdorf, M. J.

AU - Calchi Novati, S.

AU - Dodds, P.

AU - Dreizler, S.

AU - Finet, F.

AU - Gerner, T.

AU - Glitrup, M.

AU - Grundahl, F.

AU - Hardis, S.

AU - Harpsoe, K.

AU - Hinse, T. C.

AU - Hundertmark, M.

AU - Jorgensen, U. G.

AU - Kerins, E.

AU - Liebig, C.

AU - Maier, G.

AU - Mancini, L.

AU - Mathiasen, M.

AU - Penny, M. T.

AU - Proft, S.

AU - Rahvar, S.

AU - Ricci, D.

AU - Scarpetta, G.

AU - Schaefer, S.

AU - Schoenebeck, F.

AU - Skottfelt, J.

AU - Surdej, J.

AU - Southworth, J.

AU - Zimmer, F.

PY - 2012/5/20

Y1 - 2012/5/20

N2 - We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of theta(E) similar to 0.08 mas combined with the short timescale of t(E) similar to 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of similar to 0.84M(circle dot) is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.

AB - We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of theta(E) similar to 0.08 mas combined with the short timescale of t(E) similar to 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of similar to 0.84M(circle dot) is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.

KW - Galaxy: bulge

KW - gravitational lensing: micro

KW - STELLAR ATMOSPHERE MODELS

KW - GALACTIC BULGE

KW - LIGHT CURVES

KW - CHEMICAL EVOLUTION

KW - DWARF

KW - PHOTOMETRY

KW - PLANETS

KW - GIANT

KW - SIGNATURES

KW - SYSTEMS

U2 - 10.1088/0004-637X/751/1/41

DO - 10.1088/0004-637X/751/1/41

M3 - Article

SN - 0004-637X

VL - 751

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 41

ER -

CHARACTERIZING LENSES AND LENSED STARS OF HIGH-MAGNIFICATION SINGLE-LENS GRAVITATIONAL MICROLENSING EVENTS WITH LENSES PASSING OVER SOURCE STARS

Abstract

Keywords

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Astrophysics at St Andrews:2012 - 2014: Astrophysics at St Andrews: 2012 - 2014

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