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25 results on '"Scarpetta, G."'

1. Campaign 9 of the K2 Mission : Observational Parameters, Scientific Drivers, and Community Involvement for a Simultaneous Space- and Ground-based Microlensing Survey

Author

Henderson, Calen B., Poleski, Radosław, Penny, Matthew, Street, Rachel A., Bennett, David P., Hogg, David W., Gaudi, B. Scott, Zhu, W., Barclay, T., Barentsen, G., Howell, S. B., Mullally, F., Udalski, A., Szymański, M. K., Skowron, J., Mróz, P., Kozłowski, S., Wyrzykowski, Ł., Pietrukowicz, P., Soszyński, I., Ulaczyk, K., Pawlak, M., Sumi, T., Abe, F., Asakura, Y., Barry, R. K., Bhattacharya, A., Bond, I. A., Donachie, M., Freeman, M., Fukui, A., Hirao, Y., Itow, Y., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Nagakane, M., Ohnishi, K., Oyokawa, H., Rattenbury, N., Saito, To., Sharan, A., Sullivan, D. J., Tristram, P. J., Yonehara, A., Bachelet, E., Bramich, D. M., Cassan, A., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Mao, S., Ranc, C., Schmidt, R., Snodgrass, C., Steele, I. A., Tsapras, Y., Wambsganss, J., Bozza, V., Burgdorf, M. J., Jørgensen, U. G., Novati, S. Calchi, Ciceri, S., D’Ago, G., Evans, D. F., Hessman, F. V., Hinse, T. C., Husser, T.-O., Mancini, L., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Unda-Sanzana, E., Bryson, S. T., Caldwell, D. A., Haas, M. R., Larson, K., McCalmont, K., Packard, M., Peterson, C., Putnam, D., Reedy, L., Ross, S., Van Cleve, J. E., Akeson, R., Batista, V., Beaulieu, J.-P., Beichman, C. A., Bryden, G., Ciardi, D., Cole, A., Coutures, C., Foreman-Mackey, D., Fouqué, P., Friedmann, M., Gelino, C., Kaspi, S., Kerins, E., Korhonen, H., Lang, D., Lee, C.-H., Lineweaver, C. H., Maoz, D., Marquette, J.-B., Mogavero, F., Morales, J. C., Nataf, D., Pogge, R. W., Santerne, A., Shvartzvald, Y., Suzuki, D., Tamura, M., Tisserand, P., and Wang, D.

Published
2016

2. Full orbital solution for the binary system in the northern Galactic disk microlensing event Gaia16aye

Author

Wyrzykowski, Ł., D’Ago, G., Hanlon, L., van Heerden, H., Ihanec, N., Jovanovic, M., Kopacki, G., Martin-Carrillo, A., Marais, J., Meintjes, P., Murphy, D., Van Soelen, B., Strubble, E., Szegedi, H., Vernet, D., Vince, O., van der Westhuizen, I., Wium, D., Zhuchkov, R. Ya., Wyrzykowski, Łukasz, Mróz, P., Rybicki, K., Gromadzki, M., Kołaczkowski, Z., Zieliński, M., Zieliński, P., Britavskiy, N., Gomboc, A., Sokolovsky, K., Hodgkin, S., Abe, L., Aldi, G., AlMannaei, A., Altavilla, G., Al Qasim, A., Anupama, G., Awiphan, S., Bachelet, E., Bakış, V., Baker, S., Bartlett, S., Bendjoya, P., Benson, K., Bikmaev, I., Birenbaum, G., Blagorodnova, N., Blanco-Cuaresma, S., Boeva, S., Bonanos, A., Bozza, V., Bramich, D., Bruni, I., Burenin, R., Burgaz, U., Butterley, T., Caines, H., Caton, D., Calchi Novati, S., Carrasco, J., Cassan, A., Čepas, V., Cropper, M., Chruślińska, M., Clementini, G., Clerici, A., Conti, D., Conti, M., Cross, S., Cusano, F., Damljanovic, G., Dapergolas, A., D'ago, G, de Bruijne, J., Dennefeld, M., Dhillon, V., Dominik, M., Dziedzic, J., Erece, O., Eselevich, M., Esenoglu, H., Eyer, L., Figuera Jaimes, R., Fossey, S., Galeev, A., Grebenev, S., Gupta, A., Gutaev, A., Hallakoun, N., Hamanowicz, A., Han, C., Handzlik, B., Haislip, J., Hardy, L., Harrison, D., Hoette, V., Horne, K., Hudec, R., Hundertmark, M., Ihanec 35, N, Irtuganov, E., Itoh, R., Iwanek, P., Janulis, R., Jelínek, M., Jensen, E., Kaczmarek, Z., Katz, D., Khamitov, I., Kilic, Y., Klencki, J., Kolb, U., Kouprianov, V., Kruszyńska, K., Kurowski, S., Latev, G., Lee, C.-H., Leonini, S., Leto, G., Lewis, F., Li, Z., Liakos, A., Littlefair, S., Lu, J., Manser, C., Mao, S., Maoz, D., Maskoliūnas, M., Maund, J., Melnikov, S., Ment, K., Mikołajczyk, P., Morrell, M., Mowlavi, N., Moździerski, D., Nazarov, S., Netzel, H., Nesci, R., Ngeow, C.-C., Norton, A., Ofek, E., Pakštienė, E., Palaversa, L., Pandey, A., Paraskeva, E., PAWLAK, M., Penny, M., Penprase, B., Piascik, A., Prieto, J., Qvam, J., Ranc, C., Rebassa-Mansergas, A., Reichart, D., Reig, P., Rhodes, L., Rivet, J.-P., Rixon, G., Roberts, D., Rosi, P., Russell, D., Zanmar Sanchez, R., Scarpetta, G., Seabroke, G., Shappee, B., Schmidt, R., Shvartzvald, Y., Sitek, M., Skowron, J., Śniegowska, M., Snodgrass, C., Soares, P., Spetsieri, Z., Stankevičiūtė, A., Steele, I., Street, R., Strobl, J., Tinjaca Ramirez, L., Tomasella, L., Tsapras, Y., Villanueva, S., 56, O, Wambsganss, J., Wiersema, K., Wilson, R., Yoldas, A., Ya, R, Zhukov, D., Zdanavičius, J., Zoła, S., Zubareva, A., Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Instytut Astronomiczny Uniwersytetu Wrocławskiego, Instituto de Astrofìsica de Canarias, National Science Centre (Poland), European Commission, Ministry of Science and Higher Education (Poland), Science and Technology Facilities Council (UK), Foundation for Polish Science, Slovenian Research Agency, University of Crete, Foundation for Research and Technology, National Research Foundation of Korea, University of Leicester, European Space Agency, National Science Foundation (US), Ministerio de Economía y Competitividad (España), Universidad de Barcelona, Agenzia Spaziale Italiana, Royal Society (UK), Ministry of Science and Technology (Taiwan), The Ohio State University, Chinese Academy of Sciences, Villum Fonden, Research Council of Lithuania, Kazan Federal University, National Aeronautics and Space Administration (US), Ministry of Education, Science and Technological Development (Serbia), W. M. Keck Foundation, Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), School of Physics, University College Dublin, Ireland, University of Pretoria [South Africa], Clinical Center of Serbia (KCS), Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, and Ege Üniversitesi

Subjects
Astronomy, Estels binaris, gravitational lensing: micro, techniques: photometric, binaries: general, stars: individual: Gaia16aye-L, Astrophysics, 01 natural sciences, 7. Clean energy, Gaia16aye-L, Gravitational lenses, Bulge, Fotometria astronòmica, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, QB, Physics, Gravitational lensing micro, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomical photometry, 3rd-DAS, Orbital period, Radial velocity, Orbit, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Stars: individual: Gaia16aye-L, astro-ph.SR, individual: Gaia16aye [Stars], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Gravitational lensing: micro, micro [Gravitational lensing], Double stars, 0103 physical sciences, Binaries: general, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Orbital elements, general [Binaries], photometric [Techniques], Binaries, Astronomy and Astrophysics, Light curve, Stars, QC Physics, Space and Planetary Science, Física::Astronomia i astrofísica [Àrees temàtiques de la UPC], Techniques - photometric, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Techniques: photometric, astro-ph.IM
Abstract

Gaia16aye was a binary microlensing event discovered in the direction towards the northern Galactic disc and was one of the first microlensing events detected and alerted to by the Gaia space mission. Its light curve exhibited five distinct brightening episodes, reaching up to I = 12 mag, and it was covered in great detail with almost 25 000 data points gathered by a network of telescopes. We present the photometric and spectroscopic follow-up covering 500 days of the event evolution. We employed a full Keplerian binary orbit microlensing model combined with the motion of Earth and Gaia around the Sun to reproduce the complex light curve. The photometric data allowed us to solve the microlensing event entirely and to derive the complete and unique set of orbital parameters of the binary lensing system. We also report on the detection of the first-ever microlensing space-parallax between the Earth and Gaia located at L2. The properties of the binary system were derived from microlensing parameters, and we found that the system is composed of two main-sequence stars with masses 0.57 +/- 0.05 M-circle dot and 0.36 +/- 0.03 M-circle dot at 780 pc, with an orbital period of 2.88 years and an eccentricity of 0.30. We also predict the astrometric microlensing signal for this binary lens as it will be seen by Gaia as well as the radial velocity curve for the binary system. Events such as Gaia16aye indicate the potential for the microlensing method of probing the mass function of dark objects, including black holes, in directions other than that of the Galactic bulge. This case also emphasises the importance of long-term time-domain coordinated observations that can be made with a network of heterogeneous telescopes., Polish National Sci-ence Centre (NCN): HARMONIA NCN grant [2015/18/M/ST9/00544]; Polish National Sci-ence Centre (NCN): OPUS NCN grant [2015/17/B/ST9/03167]; Polish National Sci-ence Centre (NCN): DAINA NCN grant [2017/27/L/ST9/03221]; European CommissionEuropean CommissionEuropean Commission Joint Research Centre [312430, 730890]; Polish Ministry of Higher EducationMinistry of Science and Higher Education, Poland [3040/7.PR/2014/2, DIR/WK/2018/12]; MAESTRO NCN grant [2014/14/A/ST9/00121]; DDT programmes [SW2016b12, A34DDT3]; UK Science and Technology Facilities CouncilUK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC); Foundation for Polish Science (Program START); National Science Center, PolandNational Science Centre, Poland [ETIUDA 2018/28/T/ST9/00096]; Slovenian Research AgencySlovenian Research Agency - Slovenia [P1-0031, J1-8136]; COST Action GWverseEuropean Cooperation in Science and Technology (COST) [CA16104]; National Research Foundation of KoreaNational Research Foundation of Korea [2017R1A4A1015178]; STFCUK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC); European Space Agency under the NELIOTA program [4000112943]; GROWTH project - National Science Foundation [1545949]; MINECO (Spanish Ministry of Economy) [ESP2016-80079-C2-1-R, ESP2014-55996-C2-1-R, RTI2018-095076B-C21]; ICCUB (Unidad de Excelencia a Maria de Maeztu) [MDM-2014-0369]; Agenzia Spaziale Italiana (ASI)Agenzia Spaziale Italiana (ASI) [ASI I/058/10/0, ASI 2014-025-R.1.2015]; Royal Society Research GrantRoyal Society of London [RG170230]; Ministry of Science and Technology (Taiwan)Ministry of Science and Technology, Taiwan [104-2112-M-008-012MY3, 104-2923-M-008-004-MY5]; European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant [320964]; Gordon and Betty Moore FoundationGordon and Betty Moore Foundation [GBMF5490]; NSFNational Science Foundation (NSF) [AST-1515927, AST-0908816, AST-1412587]; Mt. Cuba Astronomical Foundation; Center for Cosmology and AstroParticle Physics at the Ohio State UniversityOhio State University; Chinese Academy of Sciences South America Center for Astronomy (CAS-SACA); Villum Foundation; MINECO under the Ramon y Cajal programme [RYC-2016-20254]; MINECO [AYA2017-86274-P]; AGAUR grantAgencia de Gestio D'Ajuts Universitaris de Recerca Agaur (AGAUR) [SGR-661/2017]; Science and Technology Facilities CouncilUK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC) [ST/P000541/1]; STFC consolidated grant [ST/M001296/1]; Research Council of LithuaniaResearch Council of Lithuania (LMTLT) [S-LL-19-2]; TUB.ITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); IKI; KFU; AST; National Science Fund (Bulgaria)National Science Fund of Bulgaria [DN 18/13-12.12.2017]; Institute of Astronomy via research project "Study of ICRF radio-sources and fast variable astronomical objects"; NAO Rozhen, BAS, via research project "Study of ICRF radio-sources and fast variable astronomical objects"; Ministry of Education, Science and Technological Development of the Republic of Serbia [176011, 176004, 176021]; DFGGerman Research Foundation (DFG)European Commission [SPP 1992, WA 1074/11-1]; NCN [2016/21/B/ST9/01126]; MINECO Ramon y Cajal programme [AYA2017-86274-P, RYJ-2016-20254]; Robert Martin Ayers Sciences Fund; National Aeronautics and Space AdministrationNational Aeronautics & Space Administration (NASA) [NNX08AR22G]; National Science FoundationNational Science Foundation (NSF) [AST-1238877]; W. M. Keck FoundationW.M. Keck Foundation; ICCUB (Unidad de Excelencia 'Maria de Maeztu') [MDM-2014-0369]; [3.6714.2017/8.9], This work relies on the results from the European Space Agency (ESA) space mission Gaia. Gaia data are being processed by the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC is provided by national institutions, in particular the institutions participating in the Gaia Multi-Lateral Agreement (MLA). The Gaia mission website is https://www.cosmos.esa.int/gaia.In particular we acknowledge Gaia Photomet-ric Science Alerts Team, website http://gsaweb.ast.cam.ac.uk/alerts.We thank the members of the OGLE team for discussions and support. We also would like to thank the Polish Children Fund (KFnRD) for support of an internship of their pupils in Ostrowik Observatory of the Warsaw Univ-ersity, during which some of the data were collected, in particular we thank: Robert Nowicki, Michal Por.ebski and Karol Niczyj. The work presented here has been supported by the following grants from the Polish National Sci-ence Centre (NCN): HARMONIA NCN grant 2015/18/M/ST9/00544, OPUS NCN grant 2015/17/B/ST9/03167, DAINA NCN grant 2017/27/L/ST9/03221, as well as European Commission's FP7 and H2020 OPTICON grants (312430 and 730890), Polish Ministry of Higher Education support for OPTICON FP7, 3040/7.PR/2014/2, MNiSW grant DIR/WK/2018/12. PMr and JS acknowledge support from MAESTRO NCN grant 2014/14/A/ST9/00121 to Andrzej Udal-ski. We would like to thank the following members of the AAVSO for their amazing work with collecting vast amounts of data: Teofilo Arranz, James Boardman, Stephen Brincat, Geoff Chaplin, Emery Erdelyi, Rafael Farfan, William Goff, Franklin Guenther, Kevin Hills, Jens Jacobsen, Raymond Kneip, David Lane, Fernando Limon Martinez, Gianpiero Locatelli, Andrea Mantero, Attila Madai, Peter Meadows, Otmar Nickel, Arto Oksanen, Luis Perez, Roger Pieri, Ulisse Quadri, Diego Rodriguez Perez, Frank Schorr, George Sjoberg, Andras Timar, Ray Tomlin, Tonny Vanmunster, Klaus Wenzel, Thomas Wikander. We also thank the amateur observers from around the world, in particular, Pietro Capuozzo, Leone Trascianelli, Igor Zharkov from Ardingly College and Angelo Tomassini, Karl-Ludwig Bath. We also thank Roger Pickard from the British Astronomical Association and Matthias Penselin from the German Haus der Astronomie association for their contributions. KS thanks Dr. Dmitry Chulkov and Dr. Panagiotis Gavras for the interesting discussion of stellar multiplicity. We acknowledge support of DDT programmes SW2016b12 (WHT) and A34DDT3 (TNG). The INT, TNG and WHT are operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The Liverpool Telescope is operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. SJF would like to thank the UCL students who assisted with the collection and checking of UCLO data for the observing campaign: Martina Aghopian, Ashleigh Arendt, Artem Barinov, Luke Barrett, Jasper Berry-Gair, Arjun Bhogal, Charles Bowesman, William Boyd, Andrei Cuceu, Michael Davies, Max Freedman, Gabriel Fu, Abirami Govindaraju, Iandeep Hothi, Clara Matthews Torres, Darius Modirrousta-Galian, Petru Neague, George Pattinson, Xiaoxi Song, and Brian Yu. P.Mr. acknowledges support from the Foundation for Polish Science (Program START) and the National Science Center, Poland (grant ETIUDA 2018/28/T/ST9/00096).; r r AC, AG and NI acknowledge the financial support from the Slovenian Research Agency (research core funding No. P1-0031 and project grant No. J1-8136)and networking support by the COST Action GWverse CA16104. Skinakas Observatory is a collaborative project of the University of Crete and the Foundation for Research and Technology-Hellas. Work by C.H. was supported by the grant (2017R1A4A1015178) of National Research Foundation of Korea. KW acknowledges funding from STFC, and thanks the University of Lei-cester for the investment in instrumentation. We gratefully acknowledge financial support by the European Space Agency under the NELIOTA program, contract No. 4000112943. This work has made use of data obtained with the Kryoneri Prime Focus Instrument, developed by the European Space Agency NELIOTA project on the 1.2 m Kryoneri telescope, which is operated by IAASARS, National Observatory of Athens, Greece. The Aristarchos tele-scope is operated on Helmos Observatory by the IAASARS of the National Observatory of Athens. This work was supported by the GROWTH project funded by the National Science Foundation under Grant No 1545949. This work was supported by the MINECO (Spanish Ministry of Economy) through grant ESP2016-80079-C2-1-R (MINECO/FEDER, UE) and ESP2014-55996-C2-1-R (MINECO/FEDER, UE) and MDM-2014-0369 of ICCUB (Unidad de Excelencia a Maria de Maeztu). This work was supported by the MINECO (Spanish Ministry of Economy) through grant ESP2016-80079-C2-1-R and RTI2018-095076B-C21 (MINECO/FEDER, UE), and MDM-2014-0369 of ICCUB (Unidad de Excelencia 'Maria de Maeztu'). The Joan Oro Telescope (TJO) of the Montsec Astronomical Observatory (OAdM) is owned by the Catalan Government and is operated by the Institute for Space Studies of Catalonia (IEEC). Support to this study has been provided by Agenzia Spaziale Italiana (ASI) through grants ASI I/058/10/0 and ASI 2014-025-R.1.2015. KW thanks Dipali Thanki and Ray McErlean for their technical support of the scientific programme of the University of Leicester observatory. This work was supported by Royal Society Research Grant RG170230. CCN thanks the funding from Ministry of Science and Technology (Taiwan) under the contracts 104-2112-M-008-012MY3 and 104-2923-M-008-004-MY5. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement n. 320964 (WDTracer). We thank the Las Cumbres Observatory and its sta ff for its continuing support of the project. ASAS-SN is supported by the Gordon and Betty Moore Foundation through grant GBMF5490 to the Ohio State University and NSF grant AST-1515927. Development of ASAS-SN has been supported by NSF grant AST-0908816, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics at the Ohio State University, the Chinese Academy of Sciences South America Center for Astronomy (CAS-SACA), the Villum Foundation, and George Skestos. ARM acknowledges support from the MINECO under the Ramon y Cajal programme (RYC-2016-20254) and the AYA2017-86274-P grant, and the AGAUR grant SGR-661/2017. We acknowledge support from the Science and Technology Facilities Council (TB and RWW; ST/P000541/1). K.Horne acknowledges support from STFC consolidated grant ST/M001296/1. This work was partly supported by the Research Council of Lithuania, grant No. S-LL-19-2 Authors thank to TUB.ITAK, IKI, KFU, and AST for partial supports in using RTT150 (Russian-Turkish 1.5-m telescope in Antalya).; r r This work was partially funded by the subsidy 3.6714.2017/8.9 allocated to Kazan Federal University for the state assignment in the sphere of scientific activities. This research was partially supported by contract DN 18/13-12.12.2017 with the National Science Fund (Bulgaria). Work by YS was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by Uni-versities Space Research Associ-ation through a contract with NASA. GD gratefully acknowledges the obser-ving grant support from the Institute of Astronomy and NAO Rozhen, BAS, via bilateral joint research project "Study of ICRF radio-sources and fast variable astronomical objects" (PI:G.Damljanovic). This work is a part of the Projects no. 176011 "Dynamics and kinematics of celestial bodies and systems", no. 176004 "Stellar physics" and no. 176021 "Visible and invisible matter in nearby galaxies: theory and observations" supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia. YT acknowledges the support of DFG priority program SPP 1992 "Exploring the diversity of Extrasolar Planets" (WA 1074/11-1). This work of PMi, DM and ZK was supported by the NCN grant no. 2016/21/B/ST9/01126. ARM acknowledges support from the MINECO Ramon y Cajal programme RYJ-2016-20254 and grant AYA2017-86274-P and from the AGAUR grant SGR-661/2017. The work by C. R. was supported by an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by USRA through a contract with NASA. The Faulkes Telescope Project is an education partner of Las Cumbres Observatory (LCO). The Faulkes Telescopes are maintained and operated by LCO. This research was made possible through the use of the AAVSO Photomet-ric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund and NSF AST-1412587. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project O ffice, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incor-porated, the National Central University of Taiwan, the Space Telescope Sci-ence Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Ins-titute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Published
2020

3. An analysis of binary microlensing event OGLE-2015-BLG-0060

Author

Tsapras, Y., Cassan, A., Ranc, C., Bachelet, E., Street, R., Udalski, A., Hundertmark, M., Bozza, V., Beaulieu, J. P., Marquette, J. B., Euteneuer, E., Figuera Jaimes, R., Calchi Novati, S., Bramich, D. M., Dominik, M., Jaimes, R. Figuera, Horne, K., Mao, S., Menzies, J., Schmidt, R., Snodgrass, C., Steele, I. A., Wambsganss, J., Mróz, P., Szymański, M. K., Soszyński, I., Skowron, J., Pietrukowicz, P., Kozłowski, S., Poleski, R., Ulaczyk, K., PAWLAK, M., Jørgensen, U. G., Skottfelt, J., Popovas, A., Ciceri, S., Korhonen, H., Kuffmeier, M., Evans, D. F., Peixinho, N., Hinse, T. C., Burgdorf, M. J., Southworth, J., Tronsgaard, R., Kerins, E., Andersen, M. I., Rahvar, S., Wang, Y., Wertz, O., Rabus, M., Novati, S. Calchi, D'Ago, G., Scarpetta, G., Mancini, L., Abe, F., Asakura, Y., Bennett, D. P., Bhattacharya, A., Donachie, M., Evans, P., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Koshimoto, N., Li, M. C. A., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Ohnishi, K., Rattenbury, N., Saito, T. O., Sharan, A., Shibai, H., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., Figuera Jaimes, R, Calchi Novati, S, D’Ago, G, Jaimes, R Figuera, Novati, S Calchi, Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], M2A 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Senckenberg Institute, Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science [Washington], NSF Center for EUV Science and Technology, NSF, Ifremer (COP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), CSNSM PCI, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), School of Chemical and Physical Sciences [Keele], Keele University [Keele], Okayama Astrophysical Observatory, National Astronomical Observatory of Japan (NAOJ), Department of Materials Science [Tokyo], Tokyo Institute of Technology [Tokyo] (TITECH), Laboratory for Intelligent Systems and Informatics, Department of Mechano-Informatics Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan (ISI laboratory), University of Tokyo (UTokyo), Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), NASA Goddard Space Flight Center (GSFC), Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Space Science Department of ESA, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Max-Planck-Institut für Astronomie (MPIA), Ohio State University [Columbus] (OSU), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Kuopio Unit [FMI], Finnish Meteorological Institute (FMI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (KU), Argelander Institute for Astronomy (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Instituto de Astrofisica de Canarias (IAC), Nagoya University, Department of Physics [Notre Dame], University of Notre Dame [Indiana] (UND), University of Auckland [Auckland], Osaka University [Osaka], Tokyo University of Science [Tokyo], Department of Chemistry, Université de Tsukuba = University of Tsukuba, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Space Science [Toyonaka-shi], Osaka University, Tokyo University Sci. Dept. Sci. & Technol., The University of Tokyo (UTokyo), Science & Technology Facilities Council, University of St Andrews. St Andrews Centre for Exoplanet Science, University of St Andrews. School of Physics and Astronomy, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), University of Copenhagen = Københavns Universitet (UCPH), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
GRAVITATIONAL LENS, T-EFF, Event (relativity), observational [methods], Binary number, Galaxy: Bulge, gravitational lensing: Micro, methods: Observational, techniques: Photometric, Astrophysics, gravitational lensing: micro, GALACTIC BULGE, 01 natural sciences, Galaxy: bulge, photometric [techniques], techniques: photometric, Bulge, Observatory, QB Astronomy, NETWORK, 010303 astronomy & astrophysics, QC, ComputingMilieux_MISCELLANEOUS, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, methods: observational, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], bulge [Galaxy], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Settore FIS/05 - Astronomia e Astrofisica, SYSTEMS, SEARCH, 0103 physical sciences, ALGORITHM, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, Order (ring theory), DAS, Astronomy and Astrophysics, Light curve, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], QC Physics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], DISCOVERY, astro-ph.EP, micro [gravitational lensing], Parallax, astro-ph.IM, Astrophysics - Earth and Planetary Astrophysics, PLANETS, QB799
Abstract

We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses $M_{\star1} = 0.87 \pm 0.12 M_{\odot}$ and $M_{\star2} = 0.77 \pm 0.11 M_{\odot}$. The distance to the lensing system is 6.41 $\pm 0.14$ kpc and the projected separation between the two components is 13.85 $\pm 0.16$ AU. Alternative interpretations are also considered., Comment: 13 pages, 5 figures, Published in MNRAS

Published
2019

4. MASS MEASUREMENTS of ISOLATED OBJECTS from SPACE-BASED MICROLENSING

Author

Zhu, W, Novati, SC, Gould, A, Udalski, A, Han, C, Shvartzvald, Y, Ranc, C, Jorgensen, UG, Poleski, R, Bozza, V, Beichman, C, Bryden, G, Carey, S, Gaudi, BS, Henderson, CB, Pogge, RW, Porritt, I, Wibking, B, Yee, JC, Pawlak, M, Szymanski, MK, Skowron, J, Mroz, P, Kozlowski, S, Wyrzykowski, L, Pietrukowicz, P, Pietrzynski, G, Soszynski, I, Ulaczyk, K, Choi, J-Y, Park, H, Jung, YK, Shin, I-G, Albrow, MD, Park, B-G, Kim, S-L, Lee, C-U, Cha, S-M, Kim, D-J, Lee, Y, Friedmann, M, Kaspi, S, Maoz, D, Hundertmark, M, Street, RA, Tsapras, Y, Bramich, DM, Cassan, A, Dominik, M, Bachelet, E, Dong, S, Jaimes, RF, Horne, K, Mao, S, Menzies, J, Schmidt, R, Snodgrass, C, Steele, IA, Wambsganss, J, Skottfelt, J, Andersen, MI, Burgdorf, MJ, Ciceri, S, D'Ago, G, Evans, DF, Gu, S-H, Hinse, TC, Kerins, E, Korhonen, H, Kuffmeier, M, Mancini, L, Peixinho, N, Popovas, A, Rabus, M, Rahvar, S, Tronsgaard, R, Scarpetta, G, Southworth, J, Surdej, J, von Essen, C, Wang, Y-B, Wertz, O, TEAM, S, OGLE, GRP, KMTNET, GRP, WISE, GRP, TEAM, R, MINDSTEP, GRP, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Star (game theory), PROPER MOTIONS, GRAVITATIONAL LENSING EXPERIMENT, Brown dwarf, NDAS, FOS: Physical sciences, Astrophysics, gravitational lensing: micro, GALACTIC BULGE, Gravitational microlensing, Space (mathematics), brown dwarfs, stars: fundamental parameters, Astronomy and Astrophysics, Space and Planetary Science, 01 natural sciences, fundamental parameters [Stars], law.invention, micro [Gravitational lensing], EVENTS, Settore FIS/05 - Astronomia e Astrofisica, PLANET SENSITIVITY, SYSTEMS, law, Bulge, 0103 physical sciences, QB Astronomy, QD, 010303 astronomy & astrophysics, Red clump, Solar and Stellar Astrophysics (astro-ph.SR), QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Brown dwarfs, 010308 nuclear & particles physics, OGLE-III, Lens (optics), QC Physics, Astrophysics - Solar and Stellar Astrophysics, Parallax, PARALLAX SATELLITE MASS, SPITZER OBSERVATIONS, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report on the mass and distance measurements of two single-lens events from the 2015 \emph{Spitzer} microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is very likely a brown dwarf. Assuming that the source star lies behind the same amount of dust as the Bulge red clump, we find the lens is a $45\pm7$ $M_{\rm J}$ brown dwarf at $5.9\pm1.0$ kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a $0.50\pm0.04$ $M_\odot$ star at $6.9\pm1.0$ kpc. We show that the probability to definitively measure the mass of isolated microlenses is dramatically increased once simultaneous ground- and space-based observations are conducted., Comment: 10 papers, 4 figures, 2 tables; ApJ in press

Published
2016

5. Spitzer Microlensing Program as a Probe for Globular Cluster Planets. Analysis of OGLE-2015-BLG-0448

Author

Poleski, R, Zhu, W, Christie, GW, Udalski, A, Gould, A, Bachelet, E, Skottfelt, J, Novati, SC, Szymanski, MK, Soszynski, I, Pietrzynski, G, Wyrzykowski, L, Ulaczyk, K, Pietrukowicz, P, Kozlowski, S, Skowron, J, Mroz, P, Pawlak, M, Beichman, C, Bryden, G, Carey, S, Fausnaugh, M, Gaudi, BS, Henderson, CB, Pogge, RW, Shvartzvald, Y, Wibking, B, Yee, JC, Beatty, TG, Eastman, JD, Drummond, J, Friedmann, M, Henderson, M, Johnson, JA, Kaspi, S, Maoz, D, McCormick, J, McCrady, N, Natusch, T, Ngan, H, Porritt, I, Relles, HM, Sliski, DH, Tan, T-G, Wittenmyer, RA, Wright, JT, Street, RA, Tsapras, Y, Bramich, DM, Horne, K, Snodgrass, C, Steele, IA, Menzies, J, Jaimes, RF, Wambsganss, J, Schmidt, R, Cassan, A, Ranc, C, Mao, S, Bozza, V, Dominik, M, Hundertmark, MPG, Jorgensen, UG, Andersen, MI, Burgdorf, MJ, Ciceri, S, D'Ago, G, Evans, DF, Gu, S-H, Hinse, TC, Kains, N, Kerins, E, Korhonen, H, Kuffmeier, M, Mancini, L, Popovas, A, Rabus, M, Rahvar, S, Rasmussen, RT, Scarpetta, G, Southworth, J, Surdej, J, Unda-Sanzana, E, Verma, P, von Essen, C, Wang, Y-B, Wertz, O, Grp, OGLE, Team, S, Grp, FUN, Project, R, Grp, M, and University of St Andrews. School of Physics and Astronomy

Subjects
planets and satellites: detection, Proper motion, detection [planets and satellites], NDAS, GRAVITATIONAL LENSING EXPERIMENT, FOS: Physical sciences, Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, 010501 environmental sciences, GALACTIC BULGE, Gravitational microlensing, 01 natural sciences, Settore FIS/05 - Astronomia e Astrofisica, proper motions, Planet, SYSTEMS, 0103 physical sciences, Cluster (physics), QB Astronomy, PHOTOMETRY, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, 0105 earth and related environmental sciences, QB, Physics, globular clusters: individual (NGC6558), RR LYRAE STARS, MILKY-WAY BULGE, Astronomy and Astrophysics, Radius, Light curve, OGLE-III, DIFFERENCE IMAGE-ANALYSIS, CATALOG, Space and Planetary Science, Photometry (astronomy), RED CLUMP, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Globular cluster, individual (NGC6558) [globular clusters], micro [gravitational lensing], individual: NGC6558 [Globular clusters], Astrophysics::Earth and Planetary Astrophysics
Abstract

The microlensing event OGLE-2015-BLG-0448 was observed by Spitzer and lay within the tidal radius of the globular cluster NGC 6558. The event had moderate magnification and was intensively observed, hence it had the potential to probe the distribution of planets in globular clusters. We measure the proper motion of NGC 6558 ($\mu_{\rm cl}$(N,E) = (+0.36+-0.10, +1.42+-0.10) mas/yr) as well as the source and show that the lens is not a cluster member. Even though this particular event does not probe the distribution of planets in globular clusters, other potential cluster lens events can be verified using our methodology. Additionally, we find that microlens parallax measured using OGLE photometry is consistent with the value found based on the light curve displacement between Earth and Spitzer., Comment: ApJ submitted, 12 pages, 8 figures, 2 tabels

Published
2015

6. Spitzer Microlens Measurement of a Massive Remnant in a Well-Separated Binary

Author

Shvartzvald, Y., Udalski, A., Gould, A., Han, C., Bozza, V., Friedmann, M., Hundertmark, M., Beichman, C., Bryden, G., Calchi Novati, S., Carey, S., Fausnaugh, M., Gaudi, B. S., Henderson, C. B., Kerr, T., Pogge, R. W., Varricatt, W., Wibking, B., Yee, J. C., Zhu, W., Poleski, R., Pawlak, M., Szymański, M. K., Skowron, J., Mróz, P., Kozłowski, S., Wyrzykowski, Ł., Pietrukowicz, P., Pietrzyński, G., Soszyński, I., Ulaczyk, K., Choi, J.-Y., Park, H., Jung, Y. K., Shin, I.-G., Albrow, M. D., Park, B.-G., Kim, S.-L., Lee, C.-U., Cha, S.-M., Kim, D.-J., Lee, Y., Maoz, D., Kaspi, S., Street, R. A., Tsapras, Y., Bachelet, E., Dominik, M., Bramich, D. M., Horne, Keith, Snodgrass, C., Steele, I. A., Menzies, J., Figuera Jaimes, R., Wambsganss, J., Schmidt, R., Cassan, A., Ranc, C., Mao, S., Dong, Subo, D’Ago, G., Scarpetta, G., Verma, P., Jørgensen, U. G., Kerins, E., Skottfelt, J., Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Astrophysics::High Energy Astrophysical Phenomena, black hole physics, bulge [Galaxy], NDAS, FOS: Physical sciences, Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Galaxy: bulge, micro [Gravitational lensing], stars: neutron, Bulge, Primary (astronomy), binaries: general, Space and Planetary Science, Astronomy and Astrophysics, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Adaptive optics, QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), general [Binaries], neutron [Stars], Black hole physics, Light curve, Black hole, Neutron star, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Parallax, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having $M_1>1.35\,M_\odot$ (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star or black hole. The system has a projected separation $r_\perp= 6.1\pm 0.4\,{\rm AU}$ and lies in the Galactic bulge. These measurements are based on the "microlens parallax" effect, i.e., comparing the microlensing light curve as seen from $Spitzer$, which lay at $1.25\,{\rm AU}$ projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near infrared. Future adaptive optics imaging of the companion by 30m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing black holes and neutron stars in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future $Spitzer$ and $Kepler$ K2 microlensing parallax observations., ApJ. accepted, 34 pages, 7 figures, 2 tables

Published
2015
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7. Red noise versus planetary interpretations in the microlensing event OGLE-2013-BLG-446

Author

Bachelet, E, Bramich, DM, Han, C, Greenhill, J, Street, RA, Gould, A, D'Ago, G, AlSubai, K, Dominik, M, Jaimes, RF, Horne, K, Hundertmark, M, Kains, N, Snodgrass, C, Steele, IA, Tsapras, Y, Albrow, MD, Batista, V, Beaulieu, J-P, Bennett, DP, Brillant, S, Caldwell, JAR, Cassan, A, Cole, A, Coutures, C, Dieters, S, Prester, DD, Donatowicz, J, Fouque, P, Hill, K, Marquette, J-B, Menzies, J, Pere, C, Ranc, C, Wambsganss, J, Warren, D, De Almeida, LA, Choi, J-Y, DePoy, DL, Dong, S, Hung, L-W, Hwang, K-H, Jablonski, F, Jung, YK, Kaspi, S, Klein, N, Lee, C-U, Maoz, D, Munoz, JA, Nataf, D, Park, H, Pogge, RW, Polishook, D, Shin, I-G, Shporer, A, Yee, JC, Abe, F, Bhattacharya, A, Bond, IA, Botzler, CS, Freeman, M, Fukui, A, Itow, Y, Koshimoto, N, Ling, CH, Masuda, K, Matsubara, Y, Muraki, Y, Ohnishi, K, Philpott, LC, Rattenbury, N, Saito, T, Sullivan, DJ, Sumi, T, Suzuki, D, Tristram, PJ, Yonehara, A, Bozza, V, Novati, SC, Ciceri, S, Galianni, P, Gu, S-H, Harpsoe, K, Hinse, TC, Jorgensen, UG, Juncher, D, Korhonen, H, Mancini, L, Melchiorre, C, Popovas, A, Postiglione, A, Rabus, M, Rahvar, S, Schmidt, RW, Scarpetta, G, Skottfelt, J, Southworth, J, Stabile, A, Surdej, J, Wang, X-B, Wertz, O, Collaboration, R, Collaboration, PLANET, Collaboration, FUN, Collaboration, MOA, Collaboration, M, The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Nuclear and High Energy Physics, NDAS, gravitational lensing: micro, planetary systems, techniques: photometric, FOS: Physical sciences, Astrophysics, Gravitational microlensing, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, False positive paradox, QB Astronomy, QC, QB, Event (probability theory), Physics, Earth and Planetary Astrophysics (astro-ph.EP), High magnification, photometric [Techniques], Astronomy and Astrophysics, Light curve, Exoplanet, Planetary systems, QC Physics, 13. Climate action, Space and Planetary Science, Colors of noise, Parallax, Astrophysics - Earth and Planetary Astrophysics
Abstract

For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing datasets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (A_{max} \sim 3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (\sim 3M_\oplus ) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favour the planetary interpretation when systematic errors are taken into account., Comment: accepted ApJ 2015

Published
2015
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8. OGLE-2011-BLG-0265Lb: A JOVIAN MICROLENSING PLANET ORBITING AN M DWARF

Author

Skowron, J., Shin, I. -G., Udalski, A., Han, C., Sumi, T., Shvartzvald, Y., Gould, A., Dominis Prester, D., Street, R. A., Jørgensen, U. G., Bennett, D. P., Bozza, V., Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Wyrzykowski, Ł., OGLE Collaboration, Abe, F., Bhattacharya, A., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Fukunaga, D., Itow, Y., Ling, C. H., Koshimoto, N., Masuda, K., Matsubara, Y., Muraki, Y., Namba, S., Ohnishi, K., Philpott, L. C., Rattenbury, N., Saito, T., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yock, P. C. M., MOA Collaboration, Maoz, D., Kaspi, S., Friedmann, M., Wise Group, Almeida, L. A., Batista, V., Christie, G., Choi, J. -Y., DePoy, D. L., Gaudi, B. S., Henderson, C., Hwang, K. -H., Jablonski, F., Jung, Y. K., Lee, C. -U., McCormick, J., Natusch, T., Ngan, H., Park, H., Pogge, R. W., Yee, J. C., μFUN Collaboration, Albrow, M. D., Bachelet, E., Beaulieu, J. -P., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Donatowicz, J., Fouqué, P., Greenhill, J., Kains, N., Kane, S. R., Kubas, D., Marquette, J. -B., Martin, R., Menzies, J., Pollard, K. R., Ranc, C., Sahu, K. C., Wambsganss, J., Williams, A., Wouters, D., PLANET Collaboration, Tsapras, Y., Bramich, D. M., Horne, K., Hundertmark, M., Snodgrass, C., Steele, I. A., RoboNet Collaboration, Alsubai, K. A., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dominik, M., Dreizler, S., Fang, X. -S., Gu, C. -H., Hardis, Harpsøe, K., Hessman, F. V., Hinse, T. C., Hornstrup, A., Jessen-Hansen, J., Kerins, E., Liebig, C., Lund, M., Lundkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., RICCI, DAVIDE, Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Wertz, O., MiNDSTEp Consortium, ITA, USA, GBR, DEU, ESP, BEL, KOR, DNK, IND, IRN, MEX, The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Star (game theory), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, GALACTIC BULGE, Gravitational microlensing, Jovian, JUPITER/SATURN ANALOG, Jupiter, Settore FIS/05 - Astronomia e Astrofisica, Planet, Bulge, ANGULAR SIZES, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, planetary systems, QC, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Astronomy and Astrophysics, 3rd-DAS, Planetary system, MASS PLANET, Light curve, OGLE-III, SNOW LINE, GRAVITATIONAL BINARY-LENS, QC Physics, SURFACE BRIGHTNESS RELATIONS, GIANT PLANETS, Space and Planetary Science, micro [gravitational lensing], Astrophysics::Earth and Planetary Astrophysics, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies of planetary formation and evolution. High-cadence temporal coverage of the planetary signal combined with extended observations throughout the event allows us to accurately model the observed light curve. The final microlensing solution remains, however, degenerate yielding two possible configurations of the planet and the host star. In the case of the preferred solution, the mass of the planet is $M_{\rm p} = 0.9\pm 0.3\ M_{\rm J}$, and the planet is orbiting a star with a mass $M = 0.22\pm 0.06\ M_\odot$. The second possible configuration (2$\sigma$ away) consists of a planet with $M_{\rm p}=0.6\pm 0.3\ M_{\rm J}$ and host star with $M=0.14\pm 0.06\ M_\odot$. The system is located in the Galactic disk 3 -- 4 kpc towards the Galactic bulge. In both cases, with an orbit size of 1.5 -- 2.0 AU, the planet is a "cold Jupiter" -- located well beyond the "snow line" of the host star. Currently available data make the secure selection of the correct solution difficult, but there are prospects for lifting the degeneracy with additional follow-up observations in the future, when the lens and source star separate., Comment: 10 pages, 2 tables, 5 figures. Accepted in ApJ

Published
2015

9. A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406

Author

Tsapras, Y., Choi, J.-Y., Street, R.A., Han, C., Bozza, V., Gould, A., Dominik, M., Beaulieu, J.-P., Udalski, A., Jørgensen, U.G., Sumi, T., Bramich, D.M., Browne, P., Horne, K., Hundertmark, M., Ipatov, S., Kains, N., Snodgrass, C., Steele, I.A., Alsubai, K.A., Andersen, J.M., Novati, S.C., Damerdji, Y., Diehl, C., Elyiv, A., Giannini, E., Hardis, S., Harpsøe, K., Hinse, T.C., Juncher, D., Kerins, E., Korhonen, H., Liebig, C., Mancini, L., Mathiasen, M., Penny, M.T., Rabus, M., Rahvar, S., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Vilela, C., Wambsganss, J., Skowron, J., Poleski, R., Kozłowski, S., Wyrzykowski, Ł., Szymański, M.K., Kubiak, M., Pietrukowicz, P., Pietrzyński, G., Soszyński, I., Ulaczyk, K., Albrow, M.D., Bachelet, E., Barry, R., Batista, V., Bhattacharya, A., Brillant, S., Caldwell, J.A.R., Cassan, A., Cole, A., Corrales, E., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Kane, S.R., Kubas, D., Marquette, J.-B., Menzies, J., Père, C., Pollard, K.R., Zub, M., Christie, G., Depoy, D.L., Dong, S., Drummond, J., Gaudi, B.S., Henderson, C.B., Hwang, K.H., Jung, Y.K., Kavka, A., Koo, J.-R., Lee, C.-U., Maoz, D., Monard, L.A.G., Natusch, T., Ngan, H., Park, H., Pogge, R.W., Porritt, I., Shin, I.-G., Shvartzvald, Y., Tan, T.G., Yee, J.C., Abe, F., Bennett, D.P., Bond, I.A., Botzler, C.S., Freeman, M., Fukui, A., Fukunaga, D., Itow, Y., Koshimoto, N., Ling, C.H., Masuda, K., Matsubara, Y., Muraki, Y., Namba, S., Ohnishi, K., Rattenbury, N.J., Saito, T., Sullivan, D.J., Sweatman, W.L., Suzuki, D., Tristram, P.J., Tsurumi, N., Wada, K., Yamai, N., Yock, P.C.M., Yonehara, A., The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Perturbation (astronomy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Einstein radius, micro [Gravitational lensing], Super-Jupiter, Settore FIS/05 - Astronomia e Astrofisica, Planet, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), general [Binaries], Astronomy and Astrophysics, Planetary systems, QC Physics, Space and Planetary Science, Orbital motion, Astrophysics::Earth and Planetary Astrophysics, Late-type star, Parallax, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present a detailed analysis of survey and follow-up observations of microlensing event OGLE-2012-BLG-0406 based on data obtained from 10 different observatories. Intensive coverage of the lightcurve, especially the perturbation part, allowed us to accurately measure the parallax effect and lens orbital motion. Combining our measurement of the lens parallax with the angular Einstein radius determined from finite-source effects, we estimate the physical parameters of the lens system. We find that the event was caused by a $2.73\pm 0.43\ M_{\rm J}$ planet orbiting a $0.44\pm 0.07\ M_{\odot}$ early M-type star. The distance to the lens is $4.97\pm 0.29$\ kpc and the projected separation between the host star and its planet at the time of the event is $3.45\pm 0.26$ AU. We find that the additional coverage provided by follow-up observations, especially during the planetary perturbation, leads to a more accurate determination of the physical parameters of the lens., 9 pages, 4 figures, accepted by ApJ

Published
2013

10. A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251

Author

Kains, N., Street, R.A., Choi, J.-Y., Han, C., Udalski, A., Almeida, L.A., Jablonski, F., Tristram, P.J., Jørgensen, Uffe Gråe, Szymański, M.K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Kozłowski, S., Pietrukowicz, P., Ulaczyk, K., Wyrzykowski, Ł., Skowron, J., Tsapras, Y., Alsubai, K.A., Bozza, V., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dominik, M., Dreizler, S., Fang, X.-S., Grundahl, F., Gu, C.-H., Hardis, S., Harpsøe, Kennet Bomann West, Hessman, F. V., Hinse, T. C., Hornstrup, Allan, Hundertmark, M., Jessen-Hansen, Jens, Kerins, E., Liebig, C., Lund, M., Lundkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Sahu, K.C., Scarpetta, G., Skottfelt, J., Snodgrass, C., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Bajek, D., Bramich, D.M., Horne, K., Ipatov, S., Steele, I.A., Abe, F., Bennett, D.P., Bond, I.A., Botzler, C.S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Ling, C.H., Masuda, K., Matsubara, Y, Miyake, N., Muraki, Y., Ohnishi, K., Rattenbury, N., Saito, T., Sullivan, D.J., Sumi, T., Suzuki, D., Suzuki, K., Sweatman, W.L., Takino, S., Wada, K., Yock, P.C.M., Allen, W., Batista, V., Chung, S.-J., Christie, G., Depoy, D.L., Drummond, J., Gaudi, B.S., Gould, A., Henderson, C., Jung, Y.K., Koo, J.-R., Lee, C.-U., McCormick, J., McGregor, D., Muñoz, J.A., Natusch, T., Ngan, H., Park, H., Pogge, R.W., Shin, I.-G., Yee, J., Albrow, M.D., Bachelet, E., Beaulieu, J.-P., Brillant, S., Caldwell, J.A.R., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Kane, S.R., Kubas, D., Marquette, J.-B., Martin, R., Meintjes, P., Menzies, J., Pollard, K.R., Williams, A., Wouters, D., Zub, M., Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
planets and satellites: detection, 010504 meteorology & atmospheric sciences, Satellites, bulge [Galaxy], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Discovery, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Einstein radius, Lens, gravitational lensing: weak, Settore FIS/05 - Astronomia e Astrofisica, Planet, Snow, 0103 physical sciences, gravitational lensing, weak, planets and satellites, detection, planetary systems, Galaxy, bulge, Binary, QB Astronomy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Giant planet, Systems, Search, Astronomy and Astrophysics, Radius, Frequency, Planetary system, Mass ratio, Mass, Light curve, Stars, Algorithm, detection [Planets and satellites], Planetary systems, Space and Planetary Science, Dwarf, Astrophysics::Earth and Planetary Astrophysics, weak [Gravitational lensing], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. We find that the lens is made up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a mass of 0.26 +- 0.11 M_Sun. The planetary system is located at a distance of 2.57 +- 0.61 kpc towards the Galactic Centre. The projected separation of the planet from its host star is d=1.408 +- 0.019, in units of the Einstein radius, which corresponds to 2.72 +- 0.75 AU in physical units. We also identified a competitive model with similar planet and host star masses, but with a smaller orbital radius of 1.50 +- 0.50 AU. The planet is therefore located beyond the snow line of its host star, which we estimate to be around 1-1.5 AU., 12 pages, 7 figures, 3 tables; A&A in press

Published
2013
Full Text
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11. Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs

Author

Choi, J.-Y., Han, C., Udalski, A., Sumi, T., Gaudi, B. S., Gould, A., Bennett, D. P., Dominik, M., Beaulieu, J.-P., Tsapras, Y., Bozza, V., Abe, F., Bond, I. A., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Ohnishi, K., Rattenbury, N. J., Saito, To., Sullivan, D. J., Suzuki, K., Sweatman, W. L., Suzuki, D., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., The MOA Collaboration, Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Skowron, J., Kozłowski, S., Poleski, R., Ulaczyk, K., Wyrzykowski, Ł., Pietrukowicz, P., The OGLE Collaboration, Almeida, L. A., DePoy, D. L., Dong, Subo, Gorbikov, E., Jablonski, F., Henderson, C. B., Hwang, K.-H., Janczak, J., Jung, Y.-K., Kaspi, S., Lee, C.-U., Malamud, U., Maoz, D., McGregor, D., Muñoz, J. A., Park, B.-G., Park, H., Pogge, R. W., Shvartzvald, Y., Shin, I.-G., Yee, J. C., The μFUN Collaboration, Alsubai, K. A., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Fang, X.-S., Finet, F., Glitrup, M., Grundahl, F., Gu, S.-H., Hardis, S., Harpsøe, K., Hinse, T. C., Hornstrup, A., Hundertmark, M., Jessen-Hansen, J., Jrgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, M. N., Lundkvist, M., Maier, G., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Snodgrass, C., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Zimmer, F., MiNDSTEp Consortium, The, Albrow, M. D., Bachelet, E., Batista, V., Brillant, S., Cassan, A., Cole, A. A., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Kubas, D., Marquette, J.-B., Menzies, J. W., Sahu, K. C., Zub, M., The PLANET Collaboration, Bramich, D. M., Horne, K., Steele, I. A., Street, R. A., The RoboNet Collaboration, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
binaries: general, gravitational lensing: micro, 010504 meteorology & atmospheric sciences, Population, Events, Brown dwarf, Minimum mass, Binary number, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Physics, education.field_of_study, Galactic bulge, general [Binaries], Systems, Search, Astronomy and Astrophysics, Stars, Extrasolar planets, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Low Mass, Gravitational lens
Abstract

Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low-mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 Msun and 0.034 Msun, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field brown-dwarf binaries known. The discovery of a population of such binaries indicates that brown dwarf binaries can robustly form at least down to masses of ~0.02 Msun. Future microlensing surveys will measure a mass-selected sample of brown-dwarf binary systems, which can then be directly compared to similar samples of stellar binaries., 7 pages, 5 figures, 3 tables, ApJ submitted

Published
2013

12. MOA-2010-BLG-328Lb: A SUB-NEPTUNE ORBITING VERY LATE M DWARF?

Author

Furusawa, K., Udalski, A., Sumi, T., Bennett, D. P., Bond, I. A., Gould, A., Jorgensen, U. G., Snodgrass, C., Prester, D. Dominis, Albrow, M. D., Abe, F., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Harris, P., Itow, Y., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Ohnishi, K., Rattenbury, N. J., Saito, To., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., Szymanski, M. K., Soszynski, I., Kubiak, M., Poleski, R., Ulaczyk, K., Pietrzynski, G., Wyrzykowski, L., Choi, J. Y., Christie, G. W., DePoy, D. L., Dong, S., Drummond, J., Gaudi, B. S., Han, C., Hung, L. -W., Jung, Y. -K., Lee, C. -U., McCormick, J., Moorhouse, D., Natusch, T., Nola, M., Ofek, E., Park, B. G., Park, H., Pogge, R. W., Shin, I. -G., Skowron, J., Thornley, G., Yee, J. C., Alsubai, K. A., Bozza, V., Browne, P., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dominik, M., Finet, F., Gerner, T., Hardis, S., Harpsoe, K., Hinse, T. C., Hundertmark, M., Kains, N., Kerins, E., Liebig, C., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schafer, S., Schonebeck, F., Southworth, J., Surdej, J., Wambsganss, J., Street, R. A., Bramich, D. M., Steele, I. A., Tsapras, Y., Horne, K., Donatowicz, J., Sahu, K. C., Bachelet, E., Batista, V., Beatty, T. G., Beaulieu, J. -P., Bennett, C. S., Black, C., Bowens-Rubin, R., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A. A., Corrales, E., Coutures, C., Dieters, S., Fouque, P., Greenhill, J., Henderson, C. B., Kubas, D., Marquette, J. -B., Martin, R., Menzies, J. W., Shappee, B., Williams, A., Wouters, D., van Saders, J., Zellem, R., Zub, M., Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
gravitational lensing: micro, planetary systems, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, Neptune, Planet, 0103 physical sciences, QB Astronomy, 010303 astronomy & astrophysics, QC, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Xallarap, Astronomy and Astrophysics, Planetary systems, QC Physics, Space and Planetary Science, Orbital motion, Parallax, Event (particle physics), Astrophysics - Earth and Planetary Astrophysics
Abstract

We analyze the planetary microlensing event MOA-2010-BLG-328. The best fit yields host and planetary masses of Mh = 0.11+/-0.01 M_{sun} and Mp = 9.2+/-2.2M_Earth, corresponding to a very late M dwarf and sub-Neptune-mass planet, respectively. The system lies at DL = 0.81 +/- 0.10 kpc with projected separation r = 0.92 +/- 0.16 AU. Because of the host's a-priori-unlikely close distance, as well as the unusual nature of the system, we consider the possibility that the microlens parallax signal, which determines the host mass and distance, is actually due to xallarap (source orbital motion) that is being misinterpreted as parallax. We show a result that favors the parallax solution, even given its close host distance. We show that future high-resolution astrometric measurements could decisively resolve the remaining ambiguity of these solutions., Comment: 30 pages, 6 figures. accepted for publication in ApJ. Figure 1 and 2 are updated

Published
2013

13. Microlensing Binaries with Candidate Brown Dwarf Companions

Author

Shin, I.-G., Han, C., Gould, A., Udalski, A., Sumi, T., Dominik, M., Beaulieu, J.-P., Tsapras, Y., Bozza, V., Szymański, M. K., Kubiak, M., Soszyński, I., Pietrzyński, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Ł., The OGLE Collaboration, Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., The MOA Collaboration, Christie, G. W., Depoy, D. L., Dong, S., Gal-Yam, A., Gaudi, B. S., Hung, L.-W., Janczak, J., Kaspi, S., Maoz, D., McCormick, J., McGregor, D., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Pogge, R. W., Tan, T.-G., Polishook, D., Shvartzvald, Y., Shporer, A., Thornley, G., Malamud, U., Yee, J. C., Choi, J.-Y., Jung, Y.-K., Park, H., Lee, C.-U., Park, B.-G., Koo, J.-R., The μFUN Collaboration, Bajek, D., Bramich, D. M., Browne, P., Horne, K., Ipatov, S., Snodgrass, C., Steele, I., Street, R., Alsubai, K. A., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Fang, X.-S., Grundahl, F., Gu, C.-H., Hardis, S., Harpsøe, Kennet Bomann West, Hinse, T. C., Hundertmark, M., Jessen-Hansen, J., Jørgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, Mikkel Nørup, Lundkvist, M., Mancini, L., Mathiasen, M., Hornstrup, A., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, Jesper Fælling, Southworth, J., Surdej, J., Tregloan-Reed, J., Wertz, O., Zimmer, F., Albrow, M. D., Batista, V., Brillant, S., Caldwell, J. A. R., Calitz, J. J., Cassan, A., Cole, A., Cook, K. H., Corrales, E., Coutures, Ch., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Hill, K., Hoffman, M., Kane, S. R., Kubas, D., Marquette, J.-B., Martin, R., Meintjes, P., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., Vinter, Christian, and Zub, M.

Subjects
Physics, 010308 nuclear & particles physics, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, gravitational lensing: micro, Astrophysics, Light curve, Gravitational microlensing, 01 natural sciences, Einstein radius, Stars, binaries: general, Settore FIS/05 - Astronomia e Astrofisica, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, 0103 physical sciences, brown dwarfs, Parallax, Low Mass, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation history. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during 2004 - 2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found 7 candidate events, including OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured mass of the brown dwarf companions are (0.02 +/- 0.01) M_Sun and (0.019 +/- 0.002) M_Sun for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well covered light curves increases with new generation searches., 10 pages, 9 figures, 4 tables

Published
2012

14. MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light

Author

Bachelet, E., Shin, I.-G., Han, C., Fouqué, P., Gould, A., Menzies, J.W., Beaulieu, J.-P., Bennett, D.P., Bond, I.A., Dong, Subo, Heyrovský, D., Marquette, J.-B., Marshall, J., Skowron, J., Street, R.A., Sumi, T., Udalski, A., Abe, L., Agabi, K., Albrow, M.D., Allen, W., Bertin, E., Bos, M., Bramich, D.M., Chavez, J., Christie, G.W., Cole, A.A., Crouzet, N., Dieters, S., Dominik, M., Drummond, J., Greenhill, J., Guillot, T., Henderson, C.B., Hessman, F.V., Horne, K., Hundertmark, M., Johnson, J.A., Jørgensen, U.G., Kandori, R., Liebig, C., Mékarnia, D., McCormick, J., Moorhouse, D., Nagayama, T., Nataf, D., Natusch, T., Nishiyama, S., Rivet, J.P., Sahu, K.C., Shvartzvald, Y., Thornley, G., Tomczak, A.R., Tsapras, Y., Yee, J.C., Batista, V., Bennett, C.S., Brillant, S., Caldwell, J.A.R., Cassan, A., Corrales, E., Coutures, C., Dominis Prester, D., Donatowicz, J., Kubas, D., Martin, Roland, Williams, A., Zub, M., The PLANET Collaboration, De Almeida, L., Depoy, D.L., Gaudi, B.S., Hung, L.-W., Jablonski, F., Kaspi, S., Klein, N., Lee, C.-U., Lee, Y., Koo, J.-R., Maoz, D., Muñoz, J.A., Pogge, R.W., Polishook, D., Shporer, A., The FUN Collaboration, Abe, F., Botzler, C.S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Harris, P., Itow, Y., Kobara, S., Ling, C.H., Masuda, K., Matsubara, Y., Miyake, N., Ohmori, K., Ohnishi, K., Rattenbury, N.J., Saito, To., Sullivan, D.J., Suzuki, D., Sweatman, W.L., Tristram, P.J., Wada, K., Yock, P.C.M., The MOA Collaboration, Szymanski, M.K., Soszynski, I., Kubiak, M., Poleski, R., Ulaczyk, K., Pietrzynski, G., Wyrzykowski, L., The OGLE Collaboration, Kains, N., Snodgrass, C., Steele, I.A., The RoboNet Collaboration, Alsubai, K.A., Bozza, V., Browne, P., Burgdorf, M.J., Calchi Novati, S., Dodds, P., Dreizler, S., Finet, F., Gerner, T., Hardis, S., Harpsøe, K., Hinse, T.C., Kerins, E., Mancini, L., Mathiasen, M., Penny, M.T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Southworth, J., Surdej, J., Wambsganss, J., The MiNDSTEp Consortium, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE)

Subjects
gravitational lensing: micro, planetary systems, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, 7. Clean energy, Einstein radius, Settore FIS/05 - Astronomia e Astrofisica, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Giant planet, Astronomy and Astrophysics, Mass ratio, Light curve, Orbit, 13. Climate action, Space and Planetary Science, Orbital motion, micro [gravitational lensing], gravitational lensing: micro, planetary systems, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet formation. In this paper, we report the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA-2010-BLG-477. The measured planet-star mass ratio is $q=(2.181\pm0.004)\times 10^{-3}$ and the projected separation is $s=1.1228\pm0.0006$ in units of the Einstein radius. The angular Einstein radius is unusually large $\theta_{\rm E}=1.38\pm 0.11$ mas. Combining this measurement with constraints on the "microlens parallax" and the lens flux, we can only limit the host mass to the range $0.13, Comment: 3 Tables, 12 Figures, accepted in ApJ

Published
2012

15. Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars

Author

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., Henderson, C. B., Hung, L.-W., Jablonski, F., Janczak, J., Lee, C.-U., Mallia, F., Maury, A., McCormick, J., McGregor, D., Monard, L. A. G., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Park, B.-G., Pogge, R. W., 'TG\\' Tan, T.-G., Thornley, G., Yee, J. C., The μFUN Collaboration, Abe, F., Barnard, E., Baudry, J., Bennett, D. P., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Suzuki, K., Sweatman, W. L., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., The MOA Collaboration, Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Ulaczyk, K., Wyrzykowski, Ł., Kozłowski, S., Pietrukowicz, P., The OGLE Collaboration, Albrow, M. D., Bachelet, E., Batista, V., Bennett, C. S., Bowens-Rubin, R., Brillant, S., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Kane, S. R., Menzies, J., Sahu, K. C., Wambsganss, J., Williams, A., Zub, M., The PLANET Collaboration, Allan, A., Bramich, D. M., Browne, P., Clay, N., Fraser, S., Horne, K., Kains, N., Mottram, C., Snodgrass, C., Steele, I., Tsapras, Y., The RoboNet Collaboration, Alsubai, K. A., Bozza, V., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Finet, F., Gerner, T., Glitrup, M., Grundahl, F., Hardis, S., Harpsøe, K., Hinse, T. C., Hundertmark, M., Jørgensen, U. G., Kerins, E., Liebig, C., Maier, G., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Skottfelt, Jesper Fælling, Surdej, J., Southworth, J., Zimmer, F., and MiNDSTEp Consortium, The

Subjects
Physics, 010308 nuclear & particles physics, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, gravitational lensing: micro, Astrophysics, Mass ratio, Light curve, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Galaxy: bulge, gravitational lensing: micro, Einstein radius, law.invention, Lens (optics), Stars, Astrophysics - Solar and Stellar Astrophysics, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, law, 0103 physical sciences, Surface brightness, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We present the analysis of the light curves of 9 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 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 7 events, we measure the Einstein radii and the lens-source relative proper motions. Among them, 5 events are found to have Einstein radii less than 0.2 mas, making the lenses candidates of very low-mass stars or brown dwarfs. For MOA-2011-BLG-274, especially, the small Einstein radius of $\theta_{\rm E}\sim 0.08$ mas combined with the short time scale of $t_{\rm E}\sim 2.7$ 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 $\sim 0.84\ M_\odot$ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we find planetary signals for none of events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio., Comment: 14 pages, 12 figures, 5 tables

Published
2012

16. Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing Events

Author

Shin, I.-G, Han, C., Choi, J.-Y, Udalski, A., Sumi, T., Gould, A., Bozza, V., Dominik, M., Fouque´, P., Horne, K., Szyman´ski, M. K., Kubiak, M., Soszyn´ski, I., Pietrzyn´ski, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Ł., Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Kobara, S., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Ohmori, K., Ohnishi, K., Rattenbury, N. J., Saito, To, Sullivan, D. J., Suzuki, D., Suzuki, K., Sweatman, W. L., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., MOA Collaboration, Bramich, D. M., Snodgrass, C., Steele, I. A., Street, R. A., Tsapras, Y., RoboNet Collaboration, Alsubai, K. A., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Fang, X.-S, Grundahl, Frank, Gu, C.-H, Hardis, S., Harpsøe, Kennet Bomann West, Hinse, T. C., Hornstrup, Allan, Hundertmark, M., Jessen-Hansen, Jens, Jørgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, M., Lunkkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Almeida, L. A., Batista, V., Christie, G., DePoy, D. L., Dong, Subo, Gaudi, B. S., Henderson, C., Jablonski, F., Lee, C.-U, McCormick, J., McGregor, D., Moorhouse, D., Natusch, T., Ngan, H., Park, S.-Y., Pogge, R. W., Tan, T.-G, Thornley, G., Yee, J. C., Albrow, M. D., Bachelet, E., Beaulieu, J.-P, Brillant, S., Cassan, A., Cole, A. A., Corrales, E., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Greenhill, J., Kubas, D., Marquette, J.-B, Menzies, J. W., Sahu, K. C., and Zub, M.

Subjects
binaries: general, gravitational lensing: micro, 010504 meteorology & atmospheric sciences, Binary number, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, Einstein radius, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, Binary star, binaries: general, gravitational lensing: micro, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Orbital elements, Physics, general [Binaries], Observational techniques, Astronomy and Astrophysics, Light curve, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Low Mass
Abstract

Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of 2 binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 $M_{\odot}$ and 0.39 $M_{\odot}$ for MOA-2011-BLG-090 and 0.57 $M_{\odot}$ and 0.17 $M_{\odot}$ for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future., Comment: 8 pages, 5 figures, 4 tables

Published
2012

17. Microlensing Binaries Discovered through High-Magnification Channel

Author

Shin, I.-G., Choi, J.-Y., Park, S.-Y., Han, C., Gould, A., Sumi, T., Udalski, A., Beaulieu, J.-P., Dominik, M., Allen, W., Bos, M., Christie, G. W., Depoy, D. L., Dong, S., Drummond, J., Gal-Yam, A., Gaudi, B. S., Hung, L.-W., Janczak, J., Kaspi, S., Lee, C.-U., Mallia, F., Maoz, D., Maury, A., McCormick, J., Monard, L. A. G., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Park, B.-G., Pogge, R. W., Polishook, D., Shvartzvald, Y., Shporer, A., Thornley, G., Yee, J. C., μFUN Collaboration, Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., MOA Collaboration, Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Ulaczyk, K., Wyrzykowski, Ł., Kozłowski, S., Pietrukowicz, P., OGLE Collaboration, Albrow, M. D., Batista, V., Bramich, D. M., Brillant, S., Caldwell, J. A. R., Calitz, J. J., Cassan, A., Cole, A., Cook, K. H., Corrales, E., Coutures, Ch., Dieters, S., Dominis Prester, D., Donatowicz, J., Fouqué, P., Greenhill, J., Hoffman, M., Jørgensen, U. G., Kane, S. R., Kubas, D., Marquette, J.-B., Martin, R., Meintjes, P., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., Vinter, Christian, Zub, M., PLANET Collaboration, Allan, A., Browne, P., Horne, K., Snodgrass, C., Steele, I., Street, R., Tsapras, Y., RoboNet Collaboration, Alsubai, K. A., Bozza, V., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Finet, F., Gerner, T., Glitrup, M., Grundahl, F., Hardis, S., Harpsøe, Kennet Bomann West, Hessman, F. V., Hinse, T. C., Hundertmark, M., Kains, N., Kerins, E., Liebig, C., Maier, G., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Skottfelt, Jesper Fælling, Surdej, J., Southworth, J., Zimmer, F., and MiNDSTEp Consortium

Subjects
binaries: general, gravitational lensing: micro, Binary number, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, Settore FIS/05 - Astronomia e Astrofisica, Planet, law, 0103 physical sciences, binaries: general, gravitational lensing: micro, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Mass ratio, Light curve, 3. Good health, Lens (optics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Degeneracy (mathematics), Event (particle physics)
Abstract

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of 8 binary lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a $3\sigma$ confidence level for 3 events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretic prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is $q\sim 0.1$, making the companion of the lens a strong brown-dwarf candidate., Comment: 10 figures, 6 tables, 26 pages

Published
2011

18. A sub-Saturn mass planet, MOA-2009-BLG-319Lb

Author

Miyake, N., Sumi, T., Dong, Subo, Street, R., Mancini, L., Gould, A., Bennett, D. P., Tsapras, Y., Yee, J. C., Albrow, M. D., Bond, I. A., Fouque, P., Browne, P., Han, C., Snodgrass, C., Finet, F., Furusawa, K., Harpsoe, K., Allen, W., Hundertmark, M., Freeman, M., Suzuki, D., Abe, F., Botzler, C. S., Douchin, D., Fukui, A., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Muraki, Y., Nagayama, T., Nishimoto, K., Ohnishi, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., Collaboration, The MOA, Bolt, G., Bos, M., Christie, G. W., DePoy, D. L., Drummond, J., Gal-Yam, A., Gaudi, B. S., Gorbikov, E., Higgins, D., Janczak, K. -H. Hwang J., Kaspi, S., Lee, C. -U., Koo, J. -R., lowski, S. Koz, Lee, Y., Mallia, F., Maury, A., Maoz, D., McCormick, J., Monard, L. A. G., Moorhouse, D., Mu~noz, J. A., Natusch, T., Ofek, E. O., Pogge, R. W., Polishook, D., Santallo, R., Shporer, A., Spector, O., Thornley, G., Collaboration, The Micro FUN, Allan, A., Bramich, D. M., Horne, K., Kains, N., Steele, I., Collaboration, The RoboNet, Bozza, V., Burgdorf, M. J., Novati, S. Calchi, Dominik, M., Dreizler, S., Glitrup, M., Hessman, F. V., Hinse, T. C., Jorgensen, U. G., Liebig, C., Maier, G., Mathiasen, M., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Wambsganss, J., Zimmer, F., Consortium, The MiNDSTEp, Batista, V., Beaulieu, J. P., Brillant, S., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Greenhill, J., Kubas, D., Menzies, J., and Collaboration, The PLANET

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Planetary system, Mass ratio, Gravitational microlensing, Light curve, 01 natural sciences, Einstein radius, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, Planet, Saturn, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Planetary mass, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K or M-dwarf star in the inner Galactic disk or Galactic bulge. The high cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high magnification event approximately 24 hours prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 +/- 0.02) x 10^{-4} and a separation of d = 0.97537 +/- 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t_E, and angular Einstein radius, \theta_E, along with a standard Galactic model indicates a host star mass of M_L = 0.38^{+0.34}_{-0.18} M_{Sun} and a planet mass of M_p = 50^{+44}_{-24} M_{Earth}, which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4^{+1.2}_{-0.6} AU and a distance to the planetary system of D_L = 6.1^{+1.1}_{-1.2} kpc. This separation is ~ 2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing., Comment: accepted to ApJ, 28 pages, 6 figures, 3 tables

Published
2011

19. Discovery and mass measurements of a cold, 10 earth mass planet and its host star

Author

Muraki, Y, Han, C, Bennett, Dp, Suzuki, D, Monard, Lag, Street, R, Jorgensen, Ug, Kundurthy, P, Skowron, J, Becker, Ac, Albrow, Md, Fouque, P, Heyrovsk, D, Barry, Rk, Beaulieu, J, Wellnitz, Dd, Bond, Ia, Sumi, T, Dong, S, Gaudi, Bs, Bramich, Dm, Dominik, M, Abe, F, Botzler, Cs, Freeman, M, Fukui, A, Furusawa, K, Hayashi, F, Hearnshaw, Jb, Hosaka, S, Itow, Y, Kamiya, K, Korpela, Av, Kilmartin, Pm, Lin, W, Ling, Ch, Makita, S, Masuda, K, Matsubara, Y, Miyake, N, Nishimoto, K, Ohnishi, K, Perrott, Yc, Rattenbury, Nj, Saito, T, Skuljan, L, Sullivan, Dj, Sweatman, Wl, Tristram, Pj, Wada, K, Yock, Pcm, Christie, Gw, Depoy, Dl, Gorbikov, E, Gould, A, Kaspi, S, Lee, C, Mallia, F, Maoz, D, Mccormick, J, Moorhouse, D, Natusch, T, Park, B, Pogge, Rw, Polishook, D, Shporer, A, Thornley, G, Yee, Jc, Allan, A, Browne, P, Horne, K, Kains, N, Snodgrass, C, Steele, I, Tsapras, Y, Batista, V, Bennett, Cs, Brillant, S, Caldwell, Jar, Cassan, A, Cole, A, Corrales, R, Coutures, C, Dieters, S, Dominis Prester, D, Donatowicz, J, Greenhill, J, Kubas, D, Marquette, J, Martin, R, Menzies, J, Sahu, Kc, Waldman, I, Williams, A, Zub, M, Bourhrous, H, Matsuoka, Y, Nagayama, T, Oi, N, Randriamanakoto, Z, Bozza, V, Burgdorf, Mj, Calchi Novati, S, Dreizler, S, Finet, F, Glitrup, M, Harpsoe, K, Hinse, Tc, Hundertmark, M, Liebig, C, Maier, G, Mancini, L, Mathiasen, M, Rahvar, S, Ricci, D, Scarpetta, G, Skottfelt, J, Surdej, J, Southworth, J, Wambsganss, J, Zimmer, F, Udalski, A, Poleski, R, Wyrzykowski, L, Ulaczyk, K, Szymanski, Mk, Kubiak, M, Pietrzynski, G, and Soszynski, I

Subjects
Gas giant, FOS: Physical sciences, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Settore FIS/05 - Astronomia e Astrofisica, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, planetary systems, Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Solar mass, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Light curve, Orbital period, Earth mass, 13. Climate action, Space and Planetary Science, gravitational lensing: micro, planetary systems, Astrophysics::Earth and Planetary Astrophysics, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, made with the gravitational microlensing method. This planet has a mass of m_p = 10.4 +- 1.7 Earth masses and orbits a star of mass M_* = 0.56 +- 0.09 Solar masses at a semi-major axis of a = 3.2 (+1.9 -0.5) AU and an orbital period of P = 7.6 (+7.7 -1.5} yrs. The planet and host star mass measurements are enabled by the measurement of the microlensing parallax effect, which is seen primarily in the light curve distortion due to the orbital motion of the Earth. But, the analysis also demonstrates the capability to measure microlensing parallax with the Deep Impact (or EPOXI) spacecraft in a Heliocentric orbit. The planet mass and orbital distance are similar to predictions for the critical core mass needed to accrete a substantial gaseous envelope, and thus may indicate that this planet is a "failed" gas giant. This and future microlensing detections will test planet formation theory predictions regarding the prevalence and masses of such planets., 38 pages with 7 figures

Published
2011

20. Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008

Author

Gould, A, Dong, S, Gaudi, Bs, Udalski, A, Bond, Ia, Greenhill, J, Street, Ra, Dominik, M, Sumi, T, Szymanski, Mk, Han, C, Allen, W, Bolt, G, Bos, M, Christie, Gw, Depoy, Dl, Drummond, J, Eastman, Jd, Gal-Yam, A, Higgins, D, Janczak, J, Kaspi, S, Kozllowski, S, Lee, C, Mallia, F, Maury, A, Maoz, D, Mccormick, J, Monard, Lag, Moorhouse, D, Morgan, N, Natusch, T, Ofek, Eo, Park, B, Pogge, Rw, Polishook, D, Santallo, R, Shporer, A, Spector, O, Thornley, G, Yee, Jc, Kubiak, M, Pietrzynski, G, Soszynski, I, Szewczyk, O, Wyrzykowski, E, Ulaczyk, K, Poleski, R, Abe, F, Bennett, Dp, Botzler, Cs, Douchin, D, Freeman, M, Fukui, A, Furusawa, K, Hearnshaw, Jb, Hosaka, S, Itow, Y, Kamiya, K, Kilmartin, Pm, Korpela, A, Lin, W, Ling, Ch, Makita, S, Masuda, K, Matsubara, Y, Miyake, N, Muraki, Y, Nagaya, M, Nishimoto, K, Ohnishi, K, Okumura, T, Perrott, Yc, Philpott, L, Rattenbury, N, Saito, To, Sako, T, Sullivan, Dj, Sweatman, Wl, Tristram, Pj, Von Seggern, Ev, Yock, Pcm, Albrow, M, Batista, V, Beaulieu, Jp, Brillant, S, Caldwell, J, Calitz, Jj, Cassan, A, Cole, A, Cook, K, Coutures, C, Dieters, S, Dominis Prester, D, Donatowicz, J, Fouque, P, Hill, K, Hoffman, M, Jablonski, F, Kane, Sr, Kains, N, Kubas, D, Marquette, J, Martin, R, Martioli, E, Meintjes, P, Menzies, J, Pedretti, E, Pollard, K, Sahu, Kc, Vinter, C, Wambsganss, J, Watson, R, Williams, A, Zub, M, Allan, A, Bode, Mf, Bramich, Dm, Burgdorf, Mj, Clay, N, Fraser, S, Hawkins, E, Horne, K, Kerins, E, Lister, Ta, Mottram, C, Saunders, Es, Snodgrass, C, Steele, Ia, Tsapras, Y, Jorgensen, Ug, Anguita, T, Bozza, V, Calchi Novati, S, Harpsoe, K, Hinse, Tc, Hundertmark, M, Kjaergaard, P, Liebig, C, Mancini, L, Masi, G, Mathiasen, M, Rahvar, S, Ricci, D, Scarpetta, G, Southworth, J, Surdej, J, and Thone, Cc

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), Solar System, 010504 meteorology & atmospheric sciences, Gas giant, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Planetary system, Mass ratio, Gravitational microlensing, 01 natural sciences, Einstein radius, Stars, Settore FIS/05 - Astronomia e Astrofisica, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the first measurement of planet frequency beyond the "snow line" for planet/star mass-ratios[-4.5200) microlensing events during 2005-8. The sample host stars have typical mass M_host 0.5 Msun, and detection is sensitive to planets over a range of projected separations (R_E/s_max,R_E*s_max), where R_E 3.5 AU sqrt(M_host/Msun) is the Einstein radius and s_max (q/5e-5)^{2/3}, corresponding to deprojected separations ~3 times the "snow line". Though frenetic, the observations constitute a "controlled experiment", which permits measurement of absolute planet frequency. High-mag events are rare, but the high-mag channel is efficient: half of high-mag events were successfully monitored and half of these yielded planet detections. The planet frequency derived from microlensing is a factor 7 larger than from RV studies at factor ~25 smaller separations [2, Comment: 42 pages, 10 figures

Published
2010
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21. A NEW TYPE OF AMBIGUITY IN THE PLANET AND BINARY INTERPRETATIONS OF CENTRAL PERTURBATIONS OF HIGH-MAGNIFICATION GRAVITATIONAL MICROLENSING EVENTS

Author

Choi, J.-Y, Shin, I.-G, Han, C., Udalski, A., Sumi, T., Gould, A., Bozza, V., Dominik, M., Fouque´, P., Horne, K., Szyman´ski, M. K., Kubiak, M., Soszyn´ski, I., Pietrzyn´ski, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Ł., OGLE Collaboration, Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Itow, Y., Kobara, S., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Ohmori, K., Ohnishi, K., Rattenbury, N. J., Saito, To, Sullivan, D. J., Suzuki, D., Suzuki, K., Sweatman, W. L., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., MOA Collaboration, Bramich, D. M., Snodgrass, C., Steele, I. A., Street, R. A., Tsapras, Y., RoboNet Collaboration, Alsubai, K. A., Browne, P., Burgdorf, M. J., Calchi Novati, S., Dodds, P., Dreizler, S., Fang, X.-S, Grundahl, F., Gu, C.-H, Hardis, S., Harpsøe, K., Hinse, T. C., Hornstrup, Allan, Hundertmark, M., Jessen-Hansen, J., Jørgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, M., Lunkkvist, M., Mancini, L., Mathiasen, M., Penny, M. T., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Wambsganss, J., Wertz, O., Almeida, L. A., Batista, V., Christie, G., DePoy, D. L., Dong, Subo, Gaudi, B. S., Henderson, C., Jablonski, F., Lee, C.-U, McCormick, J., McGregor, D., Moorhouse, D., Natusch, T., Ngan, H., Pogge, R. W., Tan, T.-G, Thornley, G., Yee, J. C., Albrow, M. D., Bachelet, E., Beaulieu, J.-P, Brillant, S., Cassan, A., Cole, A. A., Corrales, E., Coutures, C., Dieters, S., Dominis Prester, D., Donatowicz, J., Greenhill, J., Kubas, D., Marquette, J.-B, Menzies, J. W., Sahu, K. C., and Zub, M.

Subjects
media_common.quotation_subject, FOS: Physical sciences, Binary number, Perturbation (astronomy), gravitational lensing: micro, Astrophysics, Gravitational microlensing, 01 natural sciences, Galaxy: bulge, Settore FIS/05 - Astronomia e Astrofisica, Planet, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), media_common, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Binary Independence Model, Astronomy and Astrophysics, Ambiguity, Light curve, Galaxy: bulge, gravitational lensing: micro, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Caustic (optics), Astrophysics - Earth and Planetary Astrophysics
Abstract

High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the basically different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for 2 high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the $\chi^2$ difference between the planetary and binary model is $\sim$ 3, implying that the degeneracy is very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with $\Delta \chi^2 \sim$ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference between the planetary and binary models. Considering that 2 events observed during a single season suffer from such a degeneracy, it is expected that central perturbations experiencing this type of degeneracy is common., Comment: 8 pages, 8 figures

Published
2012

22. Probing MACHOs by observation of M 31 pixel lensing with the 1.5 m Loiano telescope

Author

G. Ingrosso, Giovanni Covone, Gaetano Scarpetta, Ph. Jetzer, A. A. Nucita, Francesco Strafella, Martin Dominik, Andrew Gould, F. De Paolis, S. Calchi Novati, Y. Giraud-Héraud, Luigi Mancini, Calchi Novati, S., Covone, Giovanni, de Paolis, F., Dominik, M., Giraud Héraud, Y., Ingrosso, G., Jetzer, P., Mancini, L., Nucita, A., Scarpetta, G., Strafella, F., Gould, A., APC - Cosmologie, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), CALCHI NOVATI, S, Covone, G, DE PAOLIS, Francesco, Dominik, M, GIRAUD HRAUD, Y, Ingrosso, Gabriele, Jetzer, Ph, Mancini, L, Nucita, Achille, Scarpetta, G, Strafella, Francesco, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Physique Corpusculaire et Cosmologie - Collège de France (PCC), and Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Gravitational lensing, FOS: Physical sciences, Astrophysics, Gravitational microlensing, 01 natural sciences, law.invention, Telescope, Galactic halo, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], astro-ph, law, 0103 physical sciences, 010303 astronomy & astrophysics, Galaxy: Halo, Physics, Pixel, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Galaxy, Stars, Variable source, Gravitational lens, Space and Planetary Science, Galaxies: M31
Abstract

We analyse a series of pilot observations in order to study microlensing of (unresolved) stars in M31 with the 1.5m Loiano telescope, including observations on both identified variable source stars and reported microlensing events. We also look for previously unknown variability and discover a nova. We discuss an observing strategy for an extended campaign with the goal of determining whether MACHOs exist or whether all microlensing events are compatible with lens stars in M31., Accepted for publication as a research Note in Astronomy & Astrophysics

Published
2007

23. A new analysis of the MEGA M31 microlensing events

Author

G. Ingrosso, S. Calchi-Novati, Francesco Strafella, F. De Paolis, Gaetano Scarpetta, Ph. Jetzer, A. A. Nucita, Hagen Kleinert, Robert T Jantzen, Remo Ruffini, Nucita, Achille, Ingrosso, Gabriele, DE PAOLIS, Francesco, Strafella, Francesco, Calchi Novati, S., Scarpetta, G., Jetzer, P. h., University of Zurich, Ingrosso, G, CALCHI NOVATI, S, Jetzer, Ph, and Scarpetta, G

Subjects
Galaxy halo, 530 Physics, gravitational lensing, Dark matter, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Time duration, Spatial distribution, Gravitational microlensing, Mega, 1912 Space and Planetary Science, Bulge, Gravitational lensing – Galaxy: halo – Galaxies: individuals: M31, Astrophysics::Galaxy Astrophysics, Physics, Mass distribution, Astrophysics (astro-ph), Astronomy, Astronomy and Astrophysics, galaxies individuals M 31, Space and Planetary Science, 10231 Institute for Computational Science, 3103 Astronomy and Astrophysics, Halo, Geology
Abstract

We discuss the results of the MEGA microlensing campaign towards M31. Our analysis is based on an analytical evaluation of the microlensing rate, taking into account the observational efficiency as given by the MEGA collaboration. In particular, we study the spatial and time duration distributions of the microlensing events for several mass distribution models of the M31 bulge. We find that only for extreme models of the M31 luminous components it is possible to reconcile the total observed MEGA events with the expected self-lensing contribution. Nevertheless, the expected spatial distribution of self-lensing events is more concentrated and hardly in agreement with the observed distribution. We find it thus difficult to explain all events as being due to self-lensing alone. On the other hand, the small number of events does not yet allow to draw firm conclusions on the halo dark matter fraction in form of MACHOs., in press on A&A

Published
2006

24. Microlensing search towards M31

Author

G. Ingrosso, Ph. Jetzer, Andrew Gould, C. Rubano, F. De Paolis, A. A. Marino, A. Bouquet, R. de Ritis, Y. Le Du, Mauro Sereno, Giovanni Covone, Gerardo Iovane, V. F. Cardone, M. Roncadelli, S. Calchi Novati, V. Bozza, Gaetano Lambiase, Ester Piedipalumbo, P. Baillon, Salvatore Capozziello, Paolo Scudellaro, Michel Aurière, V. Re, Y. Giraud-Héraud, Gaetano Scarpetta, Luigi Mancini, Francesco Strafella, Jean Kaplan, M. Capaccioli, CALCHI NOVATI, S., Iovane, G., Marino, A. A., Auriere, M., Baillon, P., Bouquet, A., Bozza, V., Capaccioli, M., Capozziello, S., Cardone, V., Covone, G., DE PAOLIS, Francesco, DE RITIS, R., GIRAUD HERAUD, Y., Gould, A., Ingrosso, Gabriele, Jetzer, P. H., Kaplan, J., Lambiase, G., LE DOU, Y., Mancini, L., Piedipalumbo, E., Re, V., Roncadelli, M., Rubano, C., Scarpetta, G., Scudellaro, P., Sereno, M., Strafella, Francesco, Capaccioli, Massimo, Capozziello, Salvatore, DE PAOLIS, F., Ingrosso, G., LE DU, Y., Piedipalumbo, Ester, Rubano, Claudio, Scudellaro, Paolo, Strafella, F., Physique Corpusculaire et Cosmologie - Collège de France (PCC), and Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics and Astronomy, observational, methods : data analysis, cosmology : observations, dark matter, gravitational lensing, galaxies : M 31, Andromeda Galaxy, Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, Dark matter, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Observable, Light curve, Space and Planetary Science, Data analysis, Halo
Abstract

We present the first results of the analysis of data collected during the 1998-99 observational campaign at the 1.3 meter McGraw-Hill Telescope, towards the Andromeda galaxy (M31), aimed to the detection of gravitational microlensing effects as a probe of the presence of dark matter in our and in M31 halo. The analysis is performed using the pixel lensing technique, which consists in the study of flux variations of unresolved sources and has been proposed and implemented by the AGAPE collaboration. We carry out a shape analysis by demanding that the detected flux variations be achromatic and compatible with a Paczynski light curve. We apply the Durbin-Watson hypothesis test to the residuals. Furthermore, we consider the background of variables sources. Finally five candidate microlensing events emerge from our selection. Comparing with the predictions of a Monte Carlo simulation, assuming a standard spherical model for the M31 and Galactic haloes, and typical values for the MACHO mass, we find that our events are only marginally consistent with the distribution of observable parameters predicted by the simulation., 13 pages, To appear in A&A

Published
2002

25. SLOTT-AGAPE project

Author

Valerio Bozza, Sebastiano Calchi Novati, Capaccioli, M., Capozziello, S., Cardone, V., Covone, G., Paolis, F., Ritis, R., Ingrosso, G., Gerardo Iovane, Gaetano Lambiase, Marino A, A., Marmo, G., Musella, I., Piedipalumbo, E., Pezzuto, S., Roncadelli, M., Rubano, C., Scarpetta, Gaetano, Scudellaro, P., Strafella, F., V., Bozza, S., Calchi Novati, M., Capaccioli, S., Capozziello, V., Cardone, G., Covone, DE PAOLIS, Francesco, R., de Riti, Ingrosso, Gabriele, G., Iovane, G., Lambiase, A. A. A., Marino, G., Marmo, I., Musella, E., Piedipalumbo, S., Pezzuto, M., Roncadelli, C., Rubano, G., Scarpetta, P., Scudellaro, Strafella, Francesco, Bozza, V., Calchi Novati, S., Capaccioli, Massimo, Capozziello, Salvatore, Cardone, V., Covone, Giovanni, de Paolis, F., de Ritis, R., Ingrosso, G., Iovane, G., Lambiase, G., Marino, A. A., Marmo, G., Musella, I., Piedipalumbo, E., Pezzuto, S., Roncadelli, M., Rubano, C., Scarpetta, G., Scudellaro, Paolo, and Strafella, F.

Subjects
Gravitational microlensing
Abstract

SLOTT-AGAPE is a new collaboration project among international partners from England, France, Germany, Switzerland and Italy thta intends top perform microlensing observations by using the M31 galaxy as target to search for MACHOs.

Published
2000

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