Full orbital solution for the binary system in the northern Galactic disc microlensing event Gaia16aye

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⊙ and 0.36 ± 0.03 M⊙ 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.

Jessica R. Lu | Z. T. Spetsieri | J. Prieto | H. Esenoglu | E. Ofek | M. Cropper | M. Penny | G. Scarpetta | K. Wiersema | J. Maund | L. Abe | J. Rivet | D. Maoz | E. Bachelet | R. Street | J. Haislip | V. Kouprianov | D. Reichart | S. Hodgkin | R. Hudec | B. Shappee | C. Ngeow | J. Wambsganss | N. Blagorodnova | N. Mowlavi | L. Eyer | M. Pawlak | K. Sokolovsky | A. Bonanos | Z. Spetsieri | A. Zubareva | J. Bruijne | G. Clementini | R. Itoh | K. Benson | G. Rixon | G. Altavilla | C. Manser | K. Rybicki | R. Wilson | I. Steele | G. Leto | D. Bramich | K. Horne | M. Dominik | S. Novati | G. Seabroke | F. Cusano | S. Littlefair | Anshu Gupta | U. Kolb | A. Norton | C. Snodgrass | D. Murphy | L. Hanlon | V. Dhillon | S. Nazarov | S. Villanueva | G. Anupama | V. Bozza | M. Hundertmark | R. Schmidt | P. Bendjoya | P. Reig | D. Vernet | I. Khamitov | R. Zanmar Sanchez | J. Klencki | L. Tomasella | J. Skowron | P. Iwanek | M. Gromadzki | P. Mróz | J. de Bruijne | D. Harrison | S. Baker | S. Blanco-Cuaresma | L. Palaversa | Ł. Wyrzykowski | D. Katz | J. Carrasco | B. Penprase | S. Mao | I. Bikmaev | R. Burenin | V. Bakış | F. Lewis | L. Hardy | A. Rebassa-Mansergas | S. Awiphan | B. V. Soelen | P. Meintjes | T. Butterley | S. Grebenev | A. Gomboc | M. Zieli'nski | P. Meintjes | D. Russell | M. Chru'sli'nska | Y. Tsapras | D. Caton | C. Han | Y. Shvartzvald | E. Paraskeva | D. Wium | E. Jensen | D. Conti | M. Dennefeld | G. D’ago | P. S. Soares | S. Fossey | A. Cassan | A. Pandey | G. Damljanovic | O. Vince | A. Martin-Carrillo | A. Yoldas | C. Ranc | S. Calchi Novati | A. Hamanowicz | A. Liakos | G. Birenbaum | N. Hallakoun | M. Eselevich | K. Ment | R. Z. Sánchez | R. Nesci | A. Piascik | R. Janulis | B. van Soelen | J. P. Marais | I. Bruni | E. Pakštienė | J. Qvam | R. Jaimes | P. Rosi | S. Bartlett | M. Jel'inek | F. Lewis | H. Caines | A. Dapergolas | Z. Kołaczkowski | G. Kopacki | H. Szegedi | S. Leonini | L. Rhodes | M. Conti | R. Zhuchkov | V. Cepas | A. Galeev | E. Irtuganov | S. Melnikov | N. Ihanec | C.-H. Lee | A. Gupta | J. Zdanavičius | D. Roberts | G. Latev | Z. Li | S. Cross | A. A. Qasim | A. AlMannaei | S. Zola | J. Štrobl | P. Zieli'nski | N. Britavskiy | G. Aldi | A. Al Qasim | S. Boeva | U. Burgaz | A. Clerici | J. Dziedzic | O. Erece | R. Figuera Jaimes | A. Gutaev | B. Handzlik | L. Hanlon | H. J. van Heerden | V. Hoette | M. Jovanovic | Z. Kaczmarek | Y. Kilic | K. Kruszyńska | S. Kurowski | J. Lu | M. Maskoliunas | P. Mikołajczyk | M. Morrell | D. Mo'zdzierski | H. Netzel | M. Sitek | M. Śniegowska | A. Stankevičiūtė | E. Strubble | L. M. Tinjaca Ramirez | I. van der Westhuizen | D. Zhukov | H. V. Heerden | S. C. Novati | M. Maskoliūnas | B. Soelen | L. M. T. Ramirez | R. Wilson | S. Cross | I. V. D. Westhuizen | A. Gupta | J. Lu | H. Esenoğlu | G. D’Ago | A. Almannaei | C. H. Lee | Sergi Blanco-Cuaresma

[1]  J. Beaulieu,et al.  Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star , 2019, The Astronomical Journal.

[2]  B. J. Shappee,et al.  First Resolution of Microlensed Images , 2018, The Astrophysical Journal.

[3]  I. Bellas-Velidis,et al.  NELIOTA: The wide-field, high-cadence, lunar monitoring system at the prime focus of the Kryoneri telescope , 2018, Astronomy & Astrophysics.

[4]  J. Beaulieu,et al.  Reconciling the Predictions of Microlensing Analysis with Radial Velocity Measurements for OGLE-2011-BLG-0417 , 2018, The Astrophysical Journal.

[5]  R. Poleski,et al.  OGLE-2017-BLG-0537: A Microlensing Event with a Resolvable Lens in ≲5 years from High-resolution Follow-up Observations , 2018, The Astrophysical Journal.

[6]  Shailey Minocha,et al.  A Robotic Telescope For University-Level Distance Teaching , 2018, 1806.02989.

[7]  P. J. Richards,et al.  Gaia Data Release 2 , 2018, Astronomy & Astrophysics.

[8]  M. Cropper,et al.  Gaia Data Release 2 , 2018, Astronomy & Astrophysics.

[9]  T. A. Lister,et al.  Gaia Data Release 2. Summary of the contents and survey properties , 2018, 1804.09365.

[10]  P. J. Richards,et al.  Gaia Data Release 2 , 2018, Astronomy & Astrophysics.

[11]  F. Strafella,et al.  Discovery of a bright microlensing event with planetary features towards the Taurus region: a super-Earth planet , 2018, 1802.06659.

[12]  J. Bruijne,et al.  On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE , 2018, 1802.03258.

[13]  C. H. Ling,et al.  OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event , 2018, 1801.05084.

[14]  Keivan G. Stassun,et al.  DEdicated MONitor of EXotransits and Transients (DEMONEXT): System Overview and Year One Results from a Low-cost Robotic Telescope for Followup of Exoplanetary Transits and Transients , 2017, 1709.05353.

[15]  A. Adams,et al.  Predicting stellar angular diameters from V, I C , H and K photometry , 2017, 1709.03902.

[16]  R. Poleski,et al.  No large population of unbound or wide-orbit Jupiter-mass planets , 2017, Nature.

[17]  Astrophysics,et al.  The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0 , 2017, 1706.07060.

[18]  J. Anderson,et al.  Microlensing Constraints on the Mass of Single Stars from HST Astrometric Measurements , 2017, 1706.04196.

[19]  B. A. Boom,et al.  GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2. , 2017, Physical review letters.

[20]  C. H. Ling,et al.  THE FIRST CIRCUMBINARY PLANET FOUND BY MICROLENSING: OGLE-2007-BLG-349L(AB)c , 2016, 1609.06720.

[21]  Gaia Collaboration,et al.  The Gaia mission , 2016, 1609.04153.

[22]  E. Ofek,et al.  A SEARCH FOR STELLAR-MASS BLACK HOLES VIA ASTROMETRIC MICROLENSING , 2016, 1607.08284.

[23]  C. H. Ling,et al.  THE FIRST SIMULTANEOUS MICROLENSING OBSERVATIONS BY TWO SPACE TELESCOPES: SPITZER AND SWIFT REVEAL A BROWN DWARF IN EVENT OGLE-2015-BLG-1319 , 2016, 1606.02292.

[24]  A. Riess,et al.  Did LIGO Detect Dark Matter? , 2016, Physical review letters.

[25]  Sang-Mok Cha,et al.  KMTNET: A NETWORK OF 1.6 M WIDE-FIELD OPTICAL TELESCOPES INSTALLED AT THREE SOUTHERN OBSERVATORIES , 2016 .

[26]  Tomasz Bulik,et al.  The first gravitational-wave source from the isolated evolution of two stars in the 40–100 solar mass range , 2016, Nature.

[27]  G. Scarpetta,et al.  MICROLENSING PARALLAX FOR OBSERVERS IN HELIOCENTRIC MOTION , 2015, 1512.09141.

[28]  E. Kerins,et al.  THE SPITZER MICROLENSING PROGRAM AS A PROBE FOR GLOBULAR CLUSTER PLANETS: ANALYSIS OF OGLE-2015-BLG-0448 , 2015, 1512.08520.

[29]  K. Ulaczyk,et al.  MASS MEASUREMENTS OF ISOLATED OBJECTS FROM SPACE-BASED MICROLENSING , 2015, 1510.02097.

[30]  V. S. Dhillon,et al.  pt5m – a 0.5 m robotic telescope on La Palma , 2015, 1509.08839.

[31]  R. Poleski,et al.  Black Hole, Neutron Star and White Dwarf Candidates from Microlensing with OGLE-III , 2015, 1509.04899.

[32]  J. Yee.  LENS MASSES AND DISTANCES FROM MICROLENS PARALLAX AND FLUX , 2015, 1509.05043.

[33]  K. Ulaczyk,et al.  SPITZER MICROLENS MEASUREMENT OF A MASSIVE REMNANT IN A WELL-SEPARATED BINARY , 2015, 1508.06636.

[34]  J. Beaulieu,et al.  The first radial velocity measurements of a microlensing event: no evidence for the predicted binary , 2015, 1506.02019.

[35]  J. Eastman,et al.  TWO STARS TWO WAYS: CONFIRMING A MICROLENSING BINARY LENS SOLUTION WITH A SPECTROSCOPIC MEASUREMENT OF THE ORBIT , 2015, 1506.01441.

[36]  K. Ulaczyk,et al.  FIRST SPACE-BASED MICROLENS PARALLAX MEASUREMENT OF AN ISOLATED STAR: SPITZER OBSERVATIONS OF OGLE-2014-BLG-0939 , 2014, 1410.5429.

[37]  K. Ulaczyk,et al.  SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR , 2014, 1410.4219.

[38]  Jan Skowron,et al.  TRIPLE MICROLENS OGLE-2008-BLG-092L: BINARY STELLAR SYSTEM WITH A CIRCUMPRIMARY URANUS-TYPE PLANET , 2014, 1408.6223.

[39]  Jan Skowron,et al.  OGLE-III MICROLENSING EVENTS AND THE STRUCTURE OF THE GALACTIC BULGE , 2014, 1405.3134.

[40]  U. Heiter,et al.  The Gaia FGK benchmark stars - High resolution spectral library , 2014, 1403.3090.

[41]  J. Prieto,et al.  THE MAN BEHIND THE CURTAIN: X-RAYS DRIVE THE UV THROUGH NIR VARIABILITY IN THE 2013 ACTIVE GALACTIC NUCLEUS OUTBURST IN NGC 2617 , 2013, 1310.2241.

[42]  E. Mamajek,et al.  INTRINSIC COLORS, TEMPERATURES, AND BOLOMETRIC CORRECTIONS OF PRE-MAIN-SEQUENCE STARS , 2013, 1307.2657.

[43]  Sergey E. Koposov,et al.  Transient astronomy with the Gaia satellite , 2013, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[44]  D. Dragomir,et al.  Las Cumbres Observatory Global Telescope Network , 2013, 1305.2437.

[45]  C. H. Ling,et al.  THE MICROLENSING EVENT RATE AND OPTICAL DEPTH TOWARD THE GALACTIC BULGE FROM MOA-II , 2013, 1305.0186.

[46]  C. H. Ling,et al.  CHARACTERIZING LOW-MASS BINARIES FROM OBSERVATION OF LONG-TIMESCALE CAUSTIC-CROSSING GRAVITATIONAL MICROLENSING EVENTS , 2012, 1204.2869.

[47]  Daniel Foreman-Mackey,et al.  emcee: The MCMC Hammer , 2012, 1202.3665.

[48]  E. Kerins,et al.  Rapidly rotating lenses: repeating features in the light curves of short-period binary microlenses , 2011, 1107.1319.

[49]  K. Ulaczyk,et al.  BINARY MICROLENSING EVENT OGLE-2009-BLG-020 GIVES VERIFIABLE MASS, DISTANCE, AND ORBIT PREDICTIONS , 2011, 1101.3312.

[50]  Douglas P. Finkbeiner,et al.  MEASURING REDDENING WITH SLOAN DIGITAL SKY SURVEY STELLAR SPECTRA AND RECALIBRATING SFD , 2010, 1012.4804.

[51]  W. Gieren,et al.  Accurate dynamical mass determination of a classical Cepheid in an eclipsing binary system , 2010, 1012.0231.

[52]  H. C. Stempels,et al.  Limb-darkening measurements for a cool red giant in microlensing event OGLE 2004-BLG-482 , 2009, 0912.2312.

[53]  S. Roweis,et al.  ASTROMETRY.NET: BLIND ASTROMETRIC CALIBRATION OF ARBITRARY ASTRONOMICAL IMAGES , 2009, 0910.2233.

[54]  M. Asplund,et al.  The chemical composition of the Sun , 2009, 0909.0948.

[55]  B. Monard,et al.  THE EXTREME MICROLENSING EVENT OGLE-2007-BLG-224: TERRESTRIAL PARALLAX OBSERVATION OF A THICK-DISK BROWN DWARF , 2009, 0904.0249.

[56]  P. Tisserand,et al.  The EROS2 search for microlensing events towards the spiral arms: the complete seven season results , 2009, 0901.1325.

[57]  J. Smithuis.  Upper secondary school , 2008 .

[58]  N. Rattenbury.  Microlensing of close binary stars , 2008, 0810.2265.

[59]  J. Skowron,et al.  Repeating microlensing events in the OGLE data , 2008, 0811.2687.

[60]  Cheongho Han,et al.  Near-Field Microlensing from Wide-Field Surveys , 2007, 0708.1215.

[61]  N. Ohishi,et al.  Observation of the First Gravitational Microlensing Event in a Sparse Stellar Field: The Tago Event , 2007, 0708.1066.

[62]  Michael E. Eyler,et al.  Discovery of a Very Bright, Nearby Gravitational Microlensing Event , 2007, astro-ph/0703125.

[63]  Los Alamos National Laboratory,et al.  The First Direct Detection of a Gravitational μ-Lens toward the Galactic Bulge , 2007, astro-ph/0701488.

[64]  J. Beaulieu,et al.  Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing , 2006, Nature.

[65]  J. Beaulieu,et al.  Galactic Bulge microlensing optical depth from EROS-2 , 2006, astro-ph/0601510.

[66]  J. Beaulieu,et al.  A Jovian-Mass Planet in Microlensing Event OGLE-2005-BLG-071 , 2005, astro-ph/0505451.

[67]  W. B. Burton,et al.  The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI - Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections , 2005, astro-ph/0504140.

[68]  Lorraine Hanlon,et al.  Watcher: A Telescope for Rapid Gamma‐Ray Burst Follow‐Up Observations , 2004 .

[69]  Gustavo A. Medrano-Cerda,et al.  The Liverpool Telescope: performance and first results , 2004, SPIE Astronomical Telescopes + Instrumentation.

[70]  D. Bennett,et al.  OGLE 2003-BLG-235/MOA 2003-BLG-53: A Planetary Microlensing Event , 2004, astro-ph/0404309.

[71]  Korea,et al.  OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens , 2003, astro-ph/0309302.

[72]  V. Belokurov,et al.  ASTROMETRIC MICROLENSING WITH THE GAIA SATELLITE , 2001, GAIA: At the Frontiers of Astrometry.

[73]  A. Gould,et al.  Microlens Mass Measurement Using Triple-Peak Events , 2001, astro-ph/0110068.

[74]  J. Beaulieu,et al.  Observation of microlensing toward the galactic spiral arms. EROS II 3 year survey , 2001 .

[75]  V. Bozza.  Trajectories of the images in binary microlensing , 2001, astro-ph/0105268.

[76]  Andrew Gould,et al.  A Natural Formalism for Microlensing , 2000, astro-ph/0001421.

[77]  O. University,et al.  Synthetic Spectra and Color-Temperature Relations of M Giants , 1999, astro-ph/9911383.

[78]  J. Beaulieu,et al.  Detection of Rotation in a Binary Microlens: PLANET Photometry of MACHO 97-BLG-41 , 1999, astro-ph/9910307.

[79]  P. Vreeswijk,et al.  The 1995 Pilot Campaign of PLANET: Searching for Microlensing Anomalies through Precise, Rapid, Round-the-Clock Monitoring , 1998, astro-ph/9807299.

[80]  M. Dominik,et al.  Astrometric Microlensing of Stars , 1998, astro-ph/9805360.

[81]  E. Bertin,et al.  SExtractor: Software for source extraction , 1996 .

[82]  B. Paczyński.  Gravitational Microlensing in the Local Group , 1996, astro-ph/9604011.

[83]  B. Peterson,et al.  The Macho Project: 45 Candidate Microlensing Events from the First Year Galactic Bulge Data , 1995, astro-ph/9512146.

[84]  S. Mao,et al.  On the Minimum Magnification between Caustic Crossings for Microlensing by Binary and Multiple Stars , 1995 .

[85]  M. Mateo,et al.  The Optical Gravitational Lensing Experiment. OGLE #7: Binary Microlens or a New Unusual Variable? , 1994, astro-ph/9407084.

[86]  K. Stanek,et al.  The Optical Depth to Gravitational Microlensing in the Direction of the Galactic Bulge , 1994, astro-ph/9407014.

[87]  Andrew Gould,et al.  MACHO Velocities from Satellite-based Parallaxes , 1994 .

[88]  Christopher J. Corbally,et al.  The calibration of MK spectral classes using spectral synthesis. 1: The effective temperature calibration of dwarf stars , 1994 .

[89]  Andrew Gould,et al.  Extending the MACHO Search to approximately 10 6 M sub sun , 1992 .

[90]  Andrew Gould,et al.  Discovering Planetary Systems through Gravitational Microlenses , 1992 .

[91]  J. Mathis,et al.  The relationship between infrared, optical, and ultraviolet extinction , 1989 .

[92]  P. Stetson.  DAOPHOT: A COMPUTER PROGRAM FOR CROWDED-FIELD STELLAR PHOTOMETRY , 1987 .

[93]  D. Popper.  Determination of Masses of Eclipsing Binary Stars , 1967 .

[94]  S. Refsdal,et al.  On the Possibility of Determining the Distances and Masses of Stars from the Gravitational Lens Effect , 1966 .

[95]  M. Galassi,et al.  GAMMA-RAY BURSTS: 30 YEARS OF DISCOVERY , 2004 .

[96]  Silvano Tizzi,et al.  Numerical procedures for thermal problems of space antennae shells , 2004 .

[97]  H. M. Dyck,et al.  Radii and Effective Temperatures for K and M Giants and Supergiants. II. , 1998 .

[98]  R. Kurucz.  ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. , 1993 .

[99]  E. Schatzman.  Particle physics and astrophysics. , 1988 .

[100]  Bohdan Paczynski,et al.  Evolutionary Processes in Close Binary Systems , 1971 .