OGLE‐2008‐BLG‐510: first automated real‐time detection of a weak microlensing anomaly – brown dwarf or stellar binary?★

V. Bozza, M. Dominik, N. J. Rattenbury, U. G. Jørgensen, Y. Tsapras, D. M. Bramich, A. Udalski, I. A. Bond, C. Liebig, A. Cassan, P. Fouqué, A. Fukui, M. Hundertmark, I.‐G. Shin, S. H. Lee, J.‐Y. Choi, S.‐Y. Park, A. Gould, A. Allan, S. MaoŁ. Wyrzykowski, R. A. Street, D. Buckley, T. Nagayama, M. Mathiasen, T. C. Hinse, S. Calchi Novati, K. Harpsøe, L. Mancini, G. Scarpetta, T. Anguita, M. J. Burgdorf, K. Horne, Allan Hornstrup, N. Kains, E. Kerins, P. Kjærgaard, G. Masi, S. Rahvar, D. Ricci, C. Snodgrass, J. Southworth, I. A. Steele, J. Surdej, C. C. Thöne, J. Wambsganss, M. Zub, M. D. Albrow, V. Batista, J.‐P. Beaulieu, D. P. Bennett, J. A. R. Caldwell, A. A. Cole, K. H. Cook, C. Coutures, S. Dieters, D. Dominis Prester, J. Donatowicz, J. Greenhill, S. R. Kane, D. Kubas, J.‐B. Marquette, R. Martin, J. Menzies, K. R. Pollard, K. C. Sahu, A. Williams, M. K. Szymański, M. Kubiak, G. Pietrzyński, I. Soszyński, R. Poleski, K. Ulaczyk, D. L. DePoy, Subo Dong, C. Han, J. Janczak, C.‐U. Lee, R. W. Pogge, F. Abe, K. Furusawa, J. B. Hearnshaw, Y. Itow, P. M. Kilmartin, A. V. Korpela, W. Lin, C. H. Ling, K. Masuda, Y. Matsubara, N. Miyake, Y. Muraki, K. Ohnishi, Y. C. Perrott, To. Saito, L. Skuljan, D. J. Sullivan, T. Sumi, D. Suzuki, W. L. Sweatman, P. J. Tristram, K. Wada, P. C. M. Yock, A. Gulbis, Y. Hashimoto, A. Kniazev, P. Vaisanen

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Abstract

The microlensing event OGLE‐2008‐BLG‐510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary‐lens and binary‐source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrate that: (1) automated real‐time detection of weak microlensing anomalies with immediate feedback is feasible, efficient and sensitive, (2) rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, (3) a modelling approach that finds all features of parameter space rather than just the ‘favourite model’ is required and (4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher order effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about the apparent paucity of both brown‐dwarf companions and binary‐source microlensing events might hide here.
Original languageEnglish
JournalRoyal Astronomical Society. Monthly Notices
Volume424
Issue number2
Pages (from-to)902-918
ISSN0035-8711
DOIs
Publication statusPublished - 2012

Cite this

Bozza, V., Dominik, M., Rattenbury, N. J., Jørgensen, U. G., Tsapras, Y., Bramich, D. M., Udalski, A., Bond, I. A., Liebig, C., Cassan, A., Fouqué, P., Fukui, A., Hundertmark, M., Shin, I. G., Lee, S. H., Choi, J. Y., Park, S. Y., Gould, A., Allan, A., ... Vaisanen, P. (2012). OGLE‐2008‐BLG‐510: first automated real‐time detection of a weak microlensing anomaly – brown dwarf or stellar binary?★. Royal Astronomical Society. Monthly Notices, 424(2), 902-918. https://doi.org/10.1111/j.1365-2966.2012.21233.x