gravitational lensing: micro; methods: data analysis; methods: statistical; planets and satellites: detection; (stars:) binaries: eclipsing; Galaxy: kinematics and dynamics
Abstract :
[en] Discussing the particularly long gravitational microlensing event OGLE-2014-BLG-1186 with a time-scale t[SUB]E[/SUB] ˜ 300 d, we present a methodology for identifying the nature of localised deviations from single-lens point-source light curves, which ensures that (1) the claimed signal is substantially above the noise floor, (2) the inferred properties are robustly determined and their estimation is not subject to confusion with systematic noise in the photometry, (3) alternative viable solutions within the model framework are not missed. Annual parallax and binarity could be separated and robustly measured from the wing and the peak data, respectively. We find matching model light curves that involve either a binary lens or a binary source, and discover hitherto unknown model ambiguities. Our binary-lens models indicate a planet of mass M[SUB]2[/SUB] = (45 ± 9) M[SUB]⊕[/SUB], orbiting a star of mass M[SUB]1[/SUB] = (0.35 ± 0.06) M[SUB]⊙[/SUB], located at a distance D[SUB]L[/SUB] = (1.7 ± 0.3) kpc from Earth, whereas our binary-source models suggest a brown-dwarf lens of M = (0.046 ± 0.007) M[SUB]⊙[/SUB], located at a distance D[SUB]L[/SUB] = (5.7 ± 0.9) kpc, with the source potentially being a (partially) eclipsing binary involving stars predicted to be of similar colour given the ratios between the luminosities and radii. Further observations might resolve the ambiguity in the interpretation in favour of either a lens or a source binary. We experienced that close binary source stars pose a challenge for claiming the detection of planets by microlensing in events where the source passes very close to the lens star hosting the planet.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Dominik, M. ; Centre for Exoplanet Science, SUPA School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
Bachelet, E.; Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, suite 102, Goleta, CA 93117, USA ; Qatar Environment and Energy Research Institute (QEERI), HBKU, Qatar Foundation, Doha, Qatar
Bozza, V.; Dipartimento di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Via Cintia, 80126 Napoli, Italy
Street, R. A.; Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, suite 102, Goleta, CA 93117, USA
Han, C.; Department of Physics, Chungbuk National University, Cheongju 28644, Republic of Korea
Hundertmark, M.; Centre for Exoplanet Science, SUPA School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK ; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark ; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg, Germany
Bramich, D. M.; New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, PO Box 129188, United Arab Emirates
Alsubai, K. A.; Qatar Environment and Energy Research Institute (QEERI), HBKU, Qatar Foundation, Doha, Qatar
Calchi Novati, S.; IPAC, Mail Code 100-22, Caltech, 1200 E. California Blvd., Pasadena, CA 91125, USA
Ciceri, S.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
D'Ago, G. ; Dipartimento di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; International Institute for Advanced Scientific Studies (IIASS), Via G. Pellegrino 19, I-84019 Vietri sul Mare (SA), Italy ; INAF - Osservatorio Astronomico di Capodimonte, Salita Moiarello 16, I-80131 Napoli, Italy ; Instituto de Astrofísica, Pontficia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
Figuera Jaimes, R.; Centre for Exoplanet Science, SUPA School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK ; Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, suite 102, Goleta, CA 93117, USA ; European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München, Germany ; Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084, China
Haugbølle, T.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark
Hinse, T. C.; Chungnam National University, Department of Astronomy and Space Science, Daejeon 34134, Republic of Korea ; Korea Astronomy & Space Science Institute, 776 Daedukdae-ro, Yuseong-gu, 305-348 Daejeon, Republic of Korea
Horne, K.; Centre for Exoplanet Science, SUPA School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
Jørgensen, U. G.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark
Juncher, D.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark
Kains, N. ; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Korhonen, H. ; Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
Mancini, L.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma, Italy ; INAF - Astrophysical Observatory of Turin, Via Osservatorio 20, I-10025 Pino Torinese, Italy
Menzies, J. ; South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa
Popovas, A. ; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark
Rabus, M. ; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; Instituto de Astrofísica, Pontficia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
Rahvar, S. ; Department of Physics, Sharif University of Technology, PO Box 11155-9161 Tehran, Iran
Scarpetta, G.; Dipartimento di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; International Institute for Advanced Scientific Studies (IIASS), Via G. Pellegrino 19, I-84019 Vietri sul Mare (SA), Italy
Schmidt, R.; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg, Germany
Skottfelt, J.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen K, Denmark ; Centre for Electronic Imaging, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
Snodgrass, C. ; Planetary and Space Science, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK ; Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen, Germany ; Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ, UK
Southworth, J.; Astrophysics Group, Keele University, Keele, Newcastle ST5 5BG, UK
Starkey, D.; Centre for Exoplanet Science, SUPA School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
Steele, I. A.; Astrophysics Research Institute, Liverpool John Moores University, Liverpool CH41 1LD, UK
Surdej, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Tsapras, Y.; Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, suite 102, Goleta, CA 93117, USA ; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg, Germany ; School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS, UK
Wambsganss, J.; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), D-69120 Heidelberg, Germany ; International Space Science Institute, Hallerstrasse 6, CH-3012 Bern, Switzerland
Wertz, O.; Institut d'Astrophysique et de Géophysique, Allée du 6 Août 19c, Sart Tilman, 4000 Liège, Belgium
Ulaczyk, K.; Warsaw University Observatory, Al. Ujazdowskie 4, PL-00-478 Warszawa, Poland ; Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
Poleski, R.; Warsaw University Observatory, Al. Ujazdowskie 4, PL-00-478 Warszawa, Poland ; Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, USA
Anderson T. W., Darling D. A., 1952, Ann. Math. Statist, 23, 193
An J. H. et al., 2002, ApJ, 572, 521
Bachelet E. et al., 2015, ApJ, 812, 136
Bachelet E., Norbury M., Bozza V., Street R., 2017, AJ, 154, 203
Beaulieu J.-P. et al., 2006, Nature, 439, 437
Bensby T. et al., 2011, A&A, 533, A134
Bond I. A. et al., 2004, ApJ, 606, L155
Bozza V. et al., 2012, MNRAS, 424, 902
Bozza V., 2010, MNRAS, 408, 2188
Bramich D. M., 2008, MNRAS, 386, L77
Bramich D. M., Freudling W., 2012, MNRAS, 424, 1584
Calchi Novati S. et al., 2015, ApJ, 804, 20
Calchi Novati S. et al., 2018, AJ, 155, 261
Chabrier G., 2003, PASP, 115, 763
Dominik M. et al., 2002, Planet. Space Sci., 50, 299
Dominik M. et al., 2007, MNRAS, 380, 792
Dominik M. et al., 2008a, in Sun Y.-S., Ferraz-Mello S., Zhou J.-L., eds, IAU Symposium Vol. 249, Exoplanets: Detection, Formation and Dynamics, Cambridge University Press, Cambridge, England, p. 35
Dominik M. et al., 2008b, Astron. Nachr., 329, 248
Dominik M. et al., 2010, Astron. Nachr., 331, 671
Dominik M., 1993, Diploma thesis, Universität Dortmund
Dominik M., 1998a, A&A, 329, 361
Dominik M., 1998b, A&A, 330, 963
Dominik M., 1998c, A&A, 333, L79
Dominik M., 1999, A&A, 349, 108
Dominik M., Hirshfeld A. C., 1996, A&A, 313, 841
Dong S. et al., 2009, ApJ, 698, 1826
Einstein A., 1915, Sitzungsber. preuss. Akad. Wiss., 47, 831
Einstein A., 1936, Science, 84, 506
Erdl H., Schneider P., 1993, A&A, 268, 453
Evans D. F. et al., 2016, A&A, 589, A58
Gaudi B. S. et al., 2008, Science, 319, 927
Gaudi B. S., 1998, ApJ, 506, 533
Gaudi B. S., Sackett P. D., 2000, ApJ, 528, 56
Gould A., 2004, ApJ, 606, 319
Gould A., Gaucherel C., 1997, ApJ, 477, 580
Gould A., Loeb A., 1992, ApJ, 396, 104
Griest K., Hu W., 1992, ApJ, 397, 362
Griest K., Safizadeh N., 1998, ApJ, 500, 37
Han C., 2001, MNRAS, 325, 1281
Han C., 2002, ApJ, 564, 1015
Han C., Lee C., 2002, MNRAS, 329, 163
Harpsøe K. B. W., Jørgensen U. G., Andersen M. I., Grundahl F., 2012, A&A, 542, A23
Hoaglin D. C., Mosteller F., Tukey J. W., eds, 1983, Understanding Robust and Exploratory Data Analysis. Wiley, New York
Horne K., Snodgrass C., Tsapras Y., 2009, MNRAS, 396, 2087
Huber P. J., Ronchetti E. M., 2009, Robust statistics, 2nd edn. Wiley, New York
Hundertmark M. et al., 2018, A&A, 609, A55
James F., Roos M., 1975, Comput. Phys. Commun., 10, 343
