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101. Inferring statistics of planet populations by means of automated microlensing searches

Author

Dominik, M., Jorgensen, U. G., Horne, K., Tsapras, Y., Street, R. A., Wyrzykowski, L., Hessman, F. V., Hundertmark, M., Rahvar, S., Wambsganss, J., Scarpetta, G., Bozza, V., Novati, S. Calchi, Mancini, L., Masi, G., Teuber, J., Hinse, T. C., Steele, I. A., Burgdorf, M. J., and Kane, S.

Subjects
Astrophysics
Abstract

(abridged) The study of other worlds is key to understanding our own, and not only provides clues to the origin of our civilization, but also looks into its future. Rather than in identifying nearby systems and learning about their individual properties, the main value of the technique of gravitational microlensing is in obtaining the statistics of planetary populations within the Milky Way and beyond. Only the complementarity of different techniques currently employed promises to yield a complete picture of planet formation that has sufficient predictive power to let us understand how habitable worlds like ours evolve, and how abundant such systems are in the Universe. A cooperative three-step strategy of survey, follow-up, and anomaly monitoring of microlensing targets, realized by means of an automated expert system and a network of ground-based telescopes is ready right now to be used to obtain a first census of cool planets with masses reaching even below that of Earth orbiting K and M dwarfs in two distinct stellar populations, namely the Galactic bulge and disk. The hunt for extra-solar planets acts as a principal science driver for time-domain astronomy with robotic-telescope networks adopting fully-automated strategies. Several initiatives, both into facilities as well as into advanced software and strategies, are supposed to see the capabilities of gravitational microlensing programmes step-wise increasing over the next 10 years. New opportunities will show up with high-precision astrometry becoming available and studying the abundance of planets around stars in neighbouring galaxies becoming possible. Finally, we should not miss out on sharing the vision with the general public, and make its realization to profit not only the scientists but all the wider society., Comment: 10 pages in PDF format. White paper submitted to ESA's Exo-Planet Roadmap Advisory Team (EPR-AT); typos corrected. The embedded figures are available from the author on request. See also "Towards A Census of Earth-mass Exo-planets with Gravitational Microlensing" by J.P. Beaulieu, E. Kerins, S. Mao et al. (arXiv:0808.0005)

Published
2008

102. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

Author

Gaudi, B. S., Bennett, D. P., Udalski, A., Gould, A., Christie, G. W., Maoz, D., Dong, S., McCormick, J., Szymanski, M. K., Tristram, P. J., Nikolaev, S., Paczynski, B., Kubiak, M., Pietrzynski, G., Soszynski, I., Szewczyk, O., Ulaczyk, K., Wyrzykowski, L., DePoy, D. L., Han, C., Kaspi, S., Lee, C. -U., Mallia, F., Natusch, T., Pogge, R. W., Park, B. -G., Abe, F., Bond, I. A., Botzler, C. S., Fukui, A., Hearnshaw, J. B., Itow, Y., Kamiya, K., Korpela, A. V., Kilmartin, P. M., Lin, W., Masuda, K., Matsubara, Y., Motomura, M., Muraki, Y., Nakamura, S., Okumura, T., Ohnishi, K., Rattenbury, N. J., Sako, T., Saito, To., Sato, S., Skuljan, L., Sullivan, D. J., Sumi, T., Sweatman, W. L., Yock, P. C. M., Albrow, M. D., Allan, A., Beaulieu, J. -P., Burgdorf, M. J., Cook, K. H., Coutures, C., Dominik, M., Dieters, S., Fouque, P., Greenhill, J., Horne, K., Steele, I., Tsapras, Y., Chaboyer, B., Crocker, A., Frank, S., and Macintosh, B.

Subjects
Astrophysics
Abstract

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of ~0.71 and ~0.27 times the mass of Jupiter and orbital separations of ~2.3 and ~4.6 astronomical units orbiting a primary star of mass ~0.50 solar masses at a distance of ~1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common., Comment: 11 pages, 2 figures, published in the 15 February 2008 issue of Science

Published
2008
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103. ARTEMiS (Automated Robotic Terrestrial Exoplanet Microlensing Search) - A possible expert-system based cooperative effort to hunt for planets of Earth mass and below

Author

Dominik, M., Horne, K., Allan, A., Rattenbury, N. J., Tsapras, Y., Snodgrass, C., Bode, M. F., Burgdorf, M. J., Fraser, S. N., Kerins, E., Mottram, C. J., Steele, I. A., Street, R. A., Wheatley, P. J., and Wyrzykowski, L.

Subjects
Astrophysics
Abstract

(abridged) The technique of gravitational microlensing is currently unique in its ability to provide a sample of terrestrial exoplanets around both Galactic disk and bulge stars, allowing to measure their abundance and determine their distribution with respect to mass and orbital separation. In order to achieve these goals in reasonable time, a well-coordinated effort involving a network of either 2m or 4 x 1m telescopes at each site is required. It could lead to the first detection of an Earth-mass planet outside the Solar system, and even planets less massive than Earth could be discovered. From April 2008, ARTEMiS (Automated Robotic Terrestrial Exoplanet Microlensing Search) is planned to provide a platform for a three-step strategy of survey, follow-up, and anomaly monitoring. As an expert system embedded in eSTAR (e-Science Telescopes for Astronomical Research), ARTEMiS will give advice on the optimal targets to be observed at any given time, and will also alert on deviations from ordinary microlensing light curves by means of the SIGNALMEN anomaly detector. While the use of the VOEvent (Virtual Observatory Event) protocol allows a direct interaction with the telescopes that are part of the HTN (Heterogeneous Telescope Networks) consortium, additional interfaces provide means of communication with all existing microlensing campaigns that rely on human observers. The success of discovering a planet by microlensing critically depends on the availability of a telescope in a suitable location at the right time, which can mean within 10 min. Real-time modelling offers the opportunity of live discovery of extra-solar planets, thereby providing ''Science live to your home''., Comment: 4 pages with 2 eps figures embedded. Accepted for publication in Astronomische Nachrichten as part of the Proceedings of the Joint VOEvent & HTN Workshop "Hot-wiring the Transient Universe" held in Tucson, Arizona (US), June 4-7 2007

Published
2008
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104. An anomaly detector with immediate feedback to hunt for planets of Earth mass and below by microlensing

Author

Dominik, M., Rattenbury, N. J., Allan, A., Mao, S., Bramich, D. M., Burgdorf, M. J., Kerins, E., Tsapras, Y., and Wyrzykowski, L.

Subjects
Astrophysics
Abstract

(abridged) The discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy exoplanet, impressively demonstrated the sensitivity of the microlensing technique to extra-solar planets below 10 M_earth. A planet of 1 M_earth in the same spot would have provided a detectable deviation with an amplitude of ~ 3 % and a duration of ~ 12 h. An early detection of a deviation could trigger higher-cadence sampling which would have allowed the discovery of an Earth-mass planet in this case. Here, we describe the implementation of an automated anomaly detector, embedded into the eSTAR system, that profits from immediate feedback provided by the robotic telescopes that form the RoboNet-1.0 network. It went into operation for the 2007 microlensing observing season. As part of our discussion about an optimal strategy for planet detection, we shed some new light on whether concentrating on highly-magnified events is promising and planets in the 'resonant' angular separation equal to the angular Einstein radius are revealed most easily. Given that sub-Neptune mass planets can be considered being common around the host stars probed by microlensing (preferentially M- and K-dwarfs), the higher number of events that can be monitored with a network of 2m telescopes and the increased detection efficiency for planets below 5 M_earth arising from an optimized strategy gives a common effort of current microlensing campaigns a fair chance to detect an Earth-mass planet (from the ground) ahead of the COROT or Kepler missions. The detection limit of gravitational microlensing extends even below 0.1 M_earth, but such planets are not very likely to be detected from current campaigns. However, these will be within the reach of high-cadence monitoring with a network of wide-field telescopes or a space-based telescope., Comment: 13 pages, 4 figures and 1 table. Accepted for publication in MNRAS

Published
2007
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105. Classical novae from the POINT-AGAPE microlensing survey of M31 -- II. Rate and statistical characteristics of the nova population

Author

Darnley, M. J., Bode, M. F., Kerins, E., Newsam, A. M., An, J., Baillon, P., Belokurov, V., Novati, S. Calchi, Carr, B. J., Creze, M., Evans, N. W., Giraud-Heraud, Y., Gould, A., Hewett, P., Jetzer, Ph., Kaplan, J., Paulin-Henriksson, S., Smartt, S. J., Tsapras, Y., and Weston, M.

Subjects
Astrophysics
Abstract

We report the results of our statistical study of the POINT-AGAPE CNe catalogue. The first Sloan $r'$ and $i'$ analysis of the MMRD relationship in M31 is performed using the resulting POINT-AGAPE CN catalogue. Good fits are produced to the MMRD in the two filters. However, we are unable to verify the $t_{15}$ relationship for either Sloan filter. The subsequent analysis of our automated CN detection pipeline has provided us with the most thorough knowledge of the completeness of a CN survey to-date. In addition, the large field of view of the survey has permitted us to probe the outburst rate well into the galactic disk, unlike previous CCD imaging surveys. Using this analysis we are able to probe the CN distribution of M31 and evaluate the global nova rate. Using models of the galactic surface brightness of M31, we show that the observed CN distribution consists of a separate bulge and disk population. We also show that the M31 bulge CN eruption rate per unit $r'$ flux is more than five times greater than that of the disk. We deduce a global M31 CN rate of $65^{+16}_{-15}$ year$^{-1}$, a value much higher than found by previous surveys. Using the global rate, we derive a M31 bulge rate of $38^{+15}_{-12}$ year$^{-1}$ and a disk rate of $27^{+19}_{-15}$ year$^{-1}$. Given our understanding of the completeness and an analysis of other sources of error, we conclude that the true global nova rate of M31 is at least 50% higher than was previously thought and this has consequent implications for the presumed CN rate in the Milky Way. We deduce a Galactic bulge rate of $14^{+6}_{-5}$ year$^{-1}$, a disk rate of $20^{+14}_{-11}$ year$^{-1}$ and a global Galactic rate of $34^{+15}_{-12}$ year$^{-1}$., Comment: 15 pages, 12 figures, submitted for publication in MNRAS

Published
2005
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106. A dearth of planetary transits in the direction of NGC 6940

Author

Hood, Ben, Cameron, Andrew Collier, Kane, Stephen R., Bramich, D. M., Horne, Keith, Street, Rachel A., Bond, I. A., Penny, A. J., Tsapras, Y., Quirrenbach, A., Safizadeh, N., Mitchell, D., and Cooke, J.

Subjects
Astrophysics
Abstract

We present results of our survey for planetary transits in the field of NGC 6940. We think nearly all of our observed stars are field stars. We have obtained high precision (3-10 millimags at the bright end) photometric observations of 50,000 stars spanning 18 nights in an attempt to identify low amplitude and short period transit events. We have used a matched filter analysis to identify 14 stars that show multiple events, and four stars that show single transits. Of these 18 candidates, we have identified two that should be further researched. However, none of the candidates are convincing hot Jupiters., Comment: 11 pages, 30 figures, mn2e.cls style, accepted to Monthly Notices of the Royal Astronomical Society 8 April 2005

Published
2005
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107. POINT-AGAPE Pixel Lensing Survey of M31 : Evidence for a MACHO contribution to Galactic Halos

Author

Novati, S. Calchi, Paulin-Henriksson, S., An, J., Baillon, P., Belokurov, V., Carr, B. J., Creze, M., Evans, N. W., Giraud-Heraud, Y., Gould, A., Hewett, P., Jetzer, Ph., Kaplan, J., Kerins, E., Smartt, S. J., Stalin, C. S., Tsapras, Y., and Weston, M. J.

Subjects
Astrophysics
Abstract

The POINT-AGAPE collaboration is carrying out a search for gravitational microlensing toward M31 to reveal galactic dark matter in the form of MACHOs (Massive Astrophysical Compact Halo Objects) in the halos of the Milky Way and M31. A high-threshold analysis of 3 years of data yields 6 bright, short--duration microlensing events, which are confronted to a simulation of the observations and the analysis. The observed signal is much larger than expected from self lensing alone and we conclude, at the 95% confidence level, that at least 20% of the halo mass in the direction of M31 must be in the form of MACHOs if their average mass lies in the range 0.5-1 M$_\odot$. This lower bound drops to 8% for MACHOs with masses $\sim 0.01$ M$_\odot$. In addition, we discuss a likely binary microlensing candidate with caustic crossing. Its location, some 32' away from the centre of M31, supports our conclusion that we are detecting a MACHO signal in the direction of M31.

Published
2005
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108. A Survey for Planetary Transits in the Field of NGC 7789

Author

Bramich, D. M., Horne, Keith, Bond, I. A., Street, R. A., Cameron, A. Collier, Hood, B., Cooke, J., James, D., Lister, T. A., Mitchell, D., Pearson, K., Penny, A., Quirrenbach, A., Safizadeh, N., and Tsapras, Y.

Subjects
Astrophysics
Abstract

We present results from 30 nights of observations of the open cluster NGC 7789 with the WFC camera on the INT telescope in La Palma. From ~900 epochs, we obtained lightcurves and Sloan r-i colours for ~33000 stars, with ~2400 stars with better than 1% precision. We expected to detect ~2 transiting hot Jupiter planets if 1% of stars host such a companion and that a typical hot Jupiter radius is ~1.2RJ. We find 24 transit candidates, 14 of which we can assign a period. We rule out the transiting planet model for 21 of these candidates using various robust arguments. For 2 candidates we are unable to decide on their nature, although it seems most likely that they are eclipsing binaries as well. We have one candidate exhibiting a single eclipse for which we derive a radius of 1.81+0.09-0.00RJ. Three candidates remain that require follow-up observations in order to determine their nature., Comment: 22 pages, 13 figures, accepted for publication in MNRAS

Published
2005
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109. The POINT-AGAPE survey II: An Unrestricted Search for Microlensing Events towards M31

Author

Belokurov, V., An, J., Evans, N. W., Hewett, P., Baillon, P., Novati, S. Calchi, Carr, B. J., Creze, M., Giraud-Heraud, Y., Gould, A., Jetzer, Ph., Kaplan, J., Kerins, E., Paulin-Henriksson, S., Smartt, S. J., Stalin, C. S., Tsapras, Y., and Weston, M. J.

Subjects
Astrophysics
Abstract

An automated search is carried out for microlensing events using a catalogue of 44554 variable superpixel lightcurves derived from our three-year monitoring program of M31. Each step of our candidate selection is objective and reproducible by a computer. Our search is unrestricted, in the sense that it has no explicit timescale cut. So, it must overcome the awkward problem of distinguishing long-timescale microlensing events from long-period stellar variables. The basis of the selection algorithm is the fitting of the superpixel lightcurves to two different theoretical models, using variable star and blended microlensing templates. Only if microlensing is preferred is an event retained as a possible candidate. Further cuts are made with regard to (i) sampling, (ii) goodness of fit of the peak to a Paczynski curve, (iii) consistency of the microlensing hypothesis with the absence of a resolved source, (iv) achromaticity, (v) position in the colour-magnitude diagram and (vi) signal-to-noise ratio. Our results are reported in terms of first-level candidates, which are the most trustworthy, and second-level candidates, which are possible microlensing but have lower signal-to-noise and are more questionable. The pipeline leaves just 3 first-level candidates, all of which have very short full-width half-maximum timescale (<5 days) and 3 second-level candidates, which have timescales of 31, 36 and 51 days respectively. We also show 16 third-level lightcurves, as an illustration of the events that just fail the threshold for designation as microlensing candidates. They are almost certainly mainly variable stars. Two of the 3 first-level candidates correspond to known events (PA 00-S3 and PA 00-S4) already reported by the POINT-AGAPE project. The remaining first-level candidate is new., Comment: 22 pages, 18 figures, MNRAS, to appear

Published
2004
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110. Classical novae from the POINT-AGAPE microlensing survey of M31 -- I. The nova catalogue

Author

Darnley, M. J., Bode, M. F., Kerins, E., Newsam, A. M., An, J., Baillon, P., Novati, S. Calchi, Carr, B. J., Creze, M., Evans, N. W., Giraud-Heraud, Y., Gould, A., Hewett, P., Jetzer, Ph., Kaplan, J., Paulin-Henriksson, S., Smartt, S. J., Stalin, C. S., and Tsapras, Y.

Subjects
Astrophysics
Abstract

The POINT-AGAPE survey is an optical search for gravitational microlensing events towards the Andromeda Galaxy (M31). As well as microlensing, the survey is sensitive to many different classes of variable stars and transients. Here we describe the automated detection and selection pipeline used to identify M31 classical novae (CNe) and we present the resulting catalogue of 20 CN candidates observed over three seasons. CNe are observed both in the bulge region as well as over a wide area of the M31 disk. Nine of the CNe are caught during the final rise phase and all are well sampled in at least two colours. The excellent light-curve coverage has allowed us to detect and classify CNe over a wide range of speed class, from very fast to very slow. Among the light-curves is a moderately fast CN exhibiting entry into a deep transition minimum, followed by its final decline. We have also observed in detail a very slow CN which faded by only 0.01 mag day$^{-1}$ over a 150 day period. We detect other interesting variable objects, including one of the longest period and most luminous Mira variables. The CN catalogue constitutes a uniquely well-sampled and objectively-selected data set with which to study the statistical properties of classical novae in M31, such as the global nova rate, the reliability of novae as standard-candle distance indicators and the dependence of the nova population on stellar environment. The findings of this statistical study will be reported in a follow-up paper., Comment: 21 pages, 13 figures, re-submitted for publication in MNRAS, typos corrected, references updated, figures 5-9 made clearer

Published
2004
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111. Dynamics of the circumstellar gas in the Herbig Ae stars BF Orionis, SV Cephei, WW Vulpeculae and XY Persei

Author

Mora, A., Eiroa, C., Natta, A., Grady, C. A., de Winter, D., Davies, J. K., Ferlet, R., Harris, A. W., Miranda, L. F., Montesinos, B., Oudmaijer, R. D., Palacios, J., Quirrenbach, A., Rauer, H., Alberdi, A., Cameron, A., Deeg, H. J., Garzon, F., Horne, K., Merin, B., Penny, A., Schneider, J., Solano, E., Tsapras, Y., and Wesselius, P. R.

Subjects
Astrophysics
Abstract

We present high resolution (lambda / Delta_lambda = 49000) echelle spectra of the intermediate mass, pre-main sequence stars BF Ori, SV Cep, WW Wul and XY Per. The spectra cover the range 3800-5900 angstroms and monitor the stars on time scales of months and days. All spectra show a large number of Balmer and metallic lines with variable blueshifted and redshifted absorption features superimposed to the photospheric stellar spectra. Synthetic Kurucz models are used to estimate rotational velocities, effective temperatures and gravities of the stars. The best photospheric models are subtracted from each observed spectrum to determine the variable absorption features due to the circumstellar gas; those features are characterized in terms of their velocity, v, dispersion velocity, Delta v, and residual absorption, R_max. The absorption components detected in each spectrum can be grouped by their similar radial velocities and are interpreted as the signature of the dynamical evolution of gaseous clumps with, in most cases, solar-like chemical composition. This infalling and outflowing gas has similar properties to the circumstellar gas observed in UX Ori, emphasizing the need for detailed theoretical models, probably in the framework of the magnetospheric accretion scenario, to understand the complex environment in Herbig Ae (HAe) stars. WW Vul is unusual because, in addition to infalling and outflowing gas with properties similar to those observed in the other stars, it shows also transient absorption features in metallic lines with no obvious counterparts in the hydrogen lines. This could, in principle, suggest the presence of CS gas clouds with enhanced metallicity around WW Vul. The existence of such a metal-rich gas component, however, needs to be confirmed by further observations and a more quantitative analysis., Comment: 21 pages, 13 figures. Accepted for publication by Astronomy & Astrophysics

Published
2004
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112. The POINT-AGAPE Survey I: The Variable Stars in M31

Author

An, Jin H., Evans, N. W., Hewett, P., Baillon, P., Novati, S. Calchi, Carr, B. J., Creze, M., Giraud-Heraud, Y., Gould, A., Jetzer, Ph., Kaplan, J., Kerins, E., Paulin-Henriksson, S., Smartt, S. J., Stalin, C. S., and Tsapras, Y.

Subjects
Astrophysics
Abstract

The POINT-AGAPE collaboration has been monitoring M31 for three seasons with the Wide Field Camera on the Isaac Newton Telescope. In each season, data are taken for one hour per night for roughly sixty nights during the six months that M31 is visible. The two fields of view straddle the central bulge, northwards and southwards. We have calculated the locations, periods and amplitudes of 35414 variable stars in M31 as a by-product of our microlensing search. The variables are classified according to their period and amplitude of variation. They are classified into population I and II Cepheids, Miras and semi-regular long-period variables. The population I Cepheids are associated with the spiral arms, while the central concentration of the Miras and long-period variables varies noticeably, the stars with brighter (and shorter) variations being much more centrally concentrated. A crucial role in the microlensing experiment is played by the asymmetry signal. It was initially assumed that the variable stars would not be a serious problem as their distributions would be symmetric. We demonstrate that this assumption is not correct. We find that differential extinction associated with the dust lanes causes the variable star distributions to be asymmetric. The size and direction of the asymmetry of the variable stars is measured as a function of period and amplitude of variation. The implications of this discovery for the successful completion of the microlensing experiments towards M31 are discussed. (Abridged), Comment: To appear in MNRAS. Revised version including additional discussion on color of variables. Additional data table will be available once the paper is published

Published
2004
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113. The Anomaly in the Candidate Microlensing Event PA-99-N2

Author

Collaboration, The POINT-AGAPE, An, J. H., Evans, N. W., Kerins, E., Baillon, P., Calchi-Novati, S., Carr, B. J., Creze, M., Giraud-Heraud, Y., Gould, A., Hewett, P., Jetzer, P., Kaplan, J., Paulin-Henriksson, S., Smartt, S. J., Tsapras, Y., and Valls-Gabaud, D.

Subjects
Astrophysics
Abstract

The lightcurve of PA-99-N2, one of the recently announced microlensing candidates towards M31, shows small deviations from the standard Paczynski form. We explore a number of possible explanations, including correlations with the seeing, the parallax effect and a binary lens. We find that the observations are consistent with an unresolved RGB or AGB star in M31 being microlensed by a binary lens. We find that the best fit binary lens mass ratio is about one hundredth, which is one of most extreme values found for a binary lens so far. If both the source and lens lie in the M31 disk, then the standard M31 model predicts the probable mass range of the system to be 0.02-3.6 solar masses (95 % confidence limit). In this scenario, the mass of the secondary component is therefore likely to be below the hydrogen-burning limit. On the other hand, if a compact halo object in M31 is lensing a disk or spheroid source, then the total lens mass is likely to lie between 0.09-32 solar masses, which is consistent with the primary being a stellar remnant and the secondary a low mass star or brown dwarf. The optical depth (or alternatively the differential rate) along the line of sight toward the event indicates that a halo lens is more likely than a stellar lens provided that dark compact objects comprise no less than 15 per cent (or 5 per cent) of haloes., Comment: Latex, 23 pages, 9 figures, in press at The Astrophysical Journal

Published
2003
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114. Theory of pixel lensing towards M31 -- II. The velocity anisotropy and flattening of the MACHO distribution

Author

Collaboration, The POINT--AGAPE, Kerins, E., An, J., Evans, N. W., Baillon, P., Carr, B. J., Giraud-Heraud, Y., Gould, A., Hewett, P., Kaplan, J., Paulin-Henriksson, S., Smartt, S. J., Tsapras, Y., and Valls-Gabaud, D.

Subjects
Astrophysics
Abstract

The POINT-AGAPE collaboration is currently searching for massive compact halo objects (MACHOs) towards the Andromeda galaxy (M31). The survey aims to exploit the high inclination of the M31 disk, which causes an asymmetry in the spatial distribution of M31 MACHOs. Here, we investigate the effects of halo velocity anisotropy and flattening on the asymmetry signal using simple halo models. For a spherically symmetric and isotropic halo, we find that the underlying pixel-lensing rate in far-disk M31 MACHOs is more than 5 times the rate of near-disk events. We find that the asymmetry is increased further by about 30% if the MACHOs occupy radial orbits rather than tangential orbits, but is substantially reduced if the MACHOs lie in a flattened halo. However, even for haloes with a minor-to-major axis ratio q = 0.3, the numbers of M31 MACHOs in the far-side outnumber those in the near-side by a factor of ~2. We show that, if positional information is exploited in addition to number counts, then the number of candidate events required to confirm asymmetry for a range of flattened and anisotropic halo models is achievable, even with significant contamination by variable stars and foreground microlensing events. For pixel-lensing surveys which probe a representative portion of the M31 disk, a sample of around 50 candidates is likely to be sufficient to detect asymmetry within spherical haloes, even if half the sample is contaminated, or to detect asymmetry in haloes as flat as q = 0.3 provided less than a third of the sample comprises contaminants. We also argue that, provided its mass-to-light ratio is less than 100, the recently observed stellar stream around M31 is not problematic for the detection of asymmetry. (Abstract slightly abridged.), Comment: latex, including 6 figures. Accepted for publication in ApJ

Published
2003
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115. Searching for Planetary Transits in the Field of Open Cluster NGC 6819 - I

Author

Street, R. A., Horne, Keith, Lister, T. A., Penny, A. J., Tsapras, Y., Quirrenbach, A., Safizadeh, N., Mitchell, D., Cooke, J., and Cameron, A. Collier

Subjects
Astrophysics
Abstract

We present results from our survey for planetary transits in the field of the intermediate age (~2.5 Gyr), metal-rich ([Fe/H]~+0.07) open cluster NGC 6819. We have obtained high-precision time-series photometry for over 38,000 stars in this field and have developed an effective matched-filter algorithm to search for photometric transits. This algorithm identified 8 candidate stars showing multiple transit-like events, plus 3 stars with single eclipses. On closer inspection, while most are shown to be low mass stellar binaries, some of these events could be due to brown dwarf companions. The data for one of the single-transit candidates indicates a minimum radius for the companion similar to that of HD 209458b., Comment: 12 pages, 7 figures, accepted by MNRAS

Published
2003
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116. A dynamical study of the circumstellar gas in UX Orionis

Author

Mora, A., Natta, A., Eiroa, C., Grady, C. A., de Winter, D., Davies, J. K., Ferlet, R., Harris, A. W., Montesinos, B., Oudmaijer, R. D., Palacios, J., Quirrenbach, A., Rauer, H., Alberdi, A., Cameron, A., Deeg, H. J., Garzon, F., Horne, K., Merin, B., Penny, A., Schneider, J., Solano, E., Tsapras, Y., and Wesselius, P. R.

Subjects
Astrophysics
Abstract

We present the results of a high spectral resolution study of the circumstellar (CS) gas around the intermediate mass, pre-main sequence star UX Ori. The results are based on a set of 10 echelle spectra, monitoring the star on time scales of months, days and hours. A large number of transient blueshifted and redshifted absorption features are detected in the Balmer and in many metallic lines. A multigaussian fit is applied to determine for each transient absorption the velocity, v, dispersion velocity, Delta v, and the parameter R, which provides a measure of the absorption strength of the CS gas. The time evolution of those parameters is presented and discussed. A comparison of intensity ratios among the transient absorptions suggests a solar-like composition of the CS gas. This confirms previous results and excludes a very metal-rich environment as the cause of the transient features in UX Ori. The features can be grouped by their similar velocities into 24 groups, of which 17 are redshifted and 7 blueshifted. An analysis of the velocity of the groups allows us to identify them as signatures of the dynamical evolution of 7 clumps of gas, of which 4 represent accretion events and 3 outflow events. Most of the events decelerate at a rate of tenths of ms-2, while 2 events accelerate at approximately the same rate; one event is seen experiencing both an acceleration and a deceleration phase and lasts for a period of few days. This time scale seems to be the typical duration of outflowing and infalling events in UX Ori. The dispersion velocity and the relative aborption strength of the features do not show drastic changes during the lifetime of the events, which suggests they are gaseous blobs preserving their geometrical and physical identity., Comment: 14 pages, 8 figures, corrected rotation period in section 5

Published
2002
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117. University of St.Andrews Open Cluster Survey for Hot Jupiters

Author

Street, R. A., Horne, Keith, Cameron, A. Collier, Tsapras, Y., Bramich, D., Penny, A., Quirrenbach, A., Safizadeh, N., Mitchell, D., and Cooke, J.

Subjects
Astrophysics
Abstract

We are using the Isaac Newton Telescope Wide Field Camera to survey open cluster fields for transiting hot Jupiter planets. Clusters were selected on the basis of visibility, richness of stars, age and metallicity. Observations of NGC 6819, 6940 and 7789 began in 1999 and continued in 2000. We have developed an effective matched-filter transit-detection algorithm which has proved its ability to identify very low amplitude eclipse events in real data. Here we present our results for NGC 6819. We have identified 7 candidates showing transit-like events. Colour information suggests that most of the companion bodies are likely to be very-low-mass stars or brown dwarfs, intrinsically interesting objects in their own right., Comment: 4 pages, 9 figures

Published
2002

118. Can Jupiters be found by monitoring Galactic Bulge microlensing events from northern sites?

Author

Tsapras, Y., Street, R., and Horne, K.

Subjects
Astrophysics
Abstract

In 1998 the EXPORT team monitored microlensing event lightcurves using a CCD camera on the IAC 0.8m telescope on Tenerife to evaluate the prospect of using northern telescopes to find microlens anomalies that reveal planets orbiting the lens stars. The high airmass and more limited time available for observations of Galactic Bulge sources makes a northern site less favourable for microlensing planet searches. However, there are potentially a large number of northern 1m class telescopes that could devote a few hours per night to monitor ongoing microlensing events. Our IAC observations indicate that accuracies sufficient to detect planets can be achieved despite the higher airmass., Comment: 8 pages, 14 figures, 1 bbl file, based on EXPORT observations, accepted by MNRAS

Published
2001
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119. LSST Survey Strategy in the Galactic Plane and Magellanic Clouds

Author

Street, R. A., primary, Li, X., additional, Khakpash, S., additional, Bellm, E., additional, Girardi, L., additional, Jones, L., additional, Abrams, N. S., additional, Tsapras, Y., additional, Hundertmark, M. P. G., additional, Bachelet, E., additional, Gandhi, P., additional, Szkody, P., additional, Clarkson, W. I., additional, Szabó, R., additional, Prisinzano, L., additional, Bonito, R., additional, Buckley, D. A. H., additional, Marais, J. P., additional, and Di Stefano, R., additional

Published
2023
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120. 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

121. MOA-2020-BLG-208Lb: Cool Sub-Saturn-mass Planet within Predicted Desert

Author

Olmschenk, Greg, primary, Bennett, David P., additional, Bond, Ian A., additional, Zang, Weicheng, additional, Jung, Youn Kil, additional, Yee, Jennifer C., additional, Bachelet, Etienne, additional, Abe, Fumio, additional, Barry, Richard K., additional, Bhattacharya, Aparna, additional, Fujii, Hirosane, additional, Fukui, Akihiko, additional, Hirao, Yuki, additional, Silva, Stela Ishitani, additional, Itow, Yoshitaka, additional, Kirikawa, Rintaro, additional, Kondo, Iona, additional, Koshimoto, Naoki, additional, Matsubara, Yutaka, additional, Matsumoto, Sho, additional, Miyazaki, Shota, additional, Munford, Brandon, additional, Muraki, Yasushi, additional, Okamura, Arisa, additional, Ranc, Clément, additional, Rattenbury, Nicholas J., additional, Satoh, Yuki, additional, Sumi, Takahiro, additional, Suzuki, Daisuke, additional, Toda, Taiga, additional, Tristram, Paul J., additional, Vandorou, Aikaterini, additional, Yama, Hibiki, additional, Albrow, Michael D., additional, Cha, Sang-Mok, additional, Chung, Sun-Ju, additional, Gould, Andrew, additional, Han, Cheongho, additional, Hwang, Kyu-Ha, additional, Kim, Dong-Jin, additional, Kim, Hyoun-Woo, additional, Kim, Seung-Lee, additional, Lee, Chung-Uk, additional, Lee, Dong-Joo, additional, Lee, Yongseok, additional, Park, Byeong-Gon, additional, Pogge, Richard W., additional, Ryu, Yoon-Hyun, additional, Shin, In-Gu, additional, Shvartzvald, Yossi, additional, Christie, Grant, additional, Cooper, Tony, additional, Drummond, John, additional, Green, Jonathan, additional, Hennerley, Steve, additional, McCormick, Jennie, additional, Monard, L. A. G., additional, Natusch, Tim, additional, Porritt, Ian, additional, Tan, Thiam-Guan, additional, Mao, Shude, additional, Maoz, Dan, additional, Penny, Matthew T., additional, Zhu, Wei, additional, Bozza, V., additional, Cassan, Arnaud, additional, Dominik, Martin, additional, Hundertmark, Markus, additional, Jaimes, R. Figuera, additional, Kruszyńska, K., additional, Rybicki, K. A., additional, Street, R. A., additional, Tsapras, Y., additional, Wambsganss, Joachim, additional, Wyrzykowski, Ł., additional, Zieliński, P., additional, and Rau, Gioia, additional

Published
2023
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122. Detailed stellar activity analysis and modelling of GJ 832

Author

Gorrini, P., Astudillo-Defru, N., Dreizler, S., Damasso, M., Díaz, R. F., Bonfils, X., Jeffers, S. V., Barnes, J. R., Del Sordo, F., Almenara, J.-M., Artigau, E., Bouchy, F., Charbonneau, D., Delfosse, X., Doyon, R., Figueira, P., Forveille, T., Haswell, C. A., López-González, M. J., Melo, C., Mennickent, R. E., Gaisné, G., Morales, N. Morales, Murgas, F., Pepe, F., Rodríguez, E., Santos, N. C., Tal-Or, L., Tsapras, Y., and Udry, S.

Abstract

Context. Gliese-832 (GJ 832) is an M2V star hosting a massive planet on a decade-long orbit, GJ 832b, discovered by radial velocity (RV). Later, a super Earth or mini-Neptune orbiting within the stellar habitable zone was reported (GJ 832c). The recently determined stellar rotation period (45.7 ± 9.3 days) is close to the orbital period of putative planet c (35.68 ± 0.03 days).\ud \ud Aims. We aim to confirm or dismiss the planetary nature of the RV signature attributed to GJ 832c, by adding 119 new RV data points, new photometric data, and an analysis of the spectroscopic stellar activity indicators. Additionally, we update the orbital parameters of the planetary system and search for additional signals.\ud \ud Methods. We performed a frequency content analysis of the RVs to search for periodic and stable signals. Radial velocity time series were modelled with Keplerians and Gaussian process (GP) regressions alongside activity indicators to subsequently compare them within a Bayesian framework.\ud \ud Results. We updated the stellar rotational period of GJ 832 from activity indicators, obtaining 37.5+1.4-1.5 days, improving the precision by a factor of 6. The new photometric data are in agreement with this value. We detected an RV signal near 18 days (FAP < 4.6%), which is half of the stellar rotation period. Two Keplerians alone fail at modelling GJ 832b and a second planet with a 35-day orbital period. Moreover, the Bayesian evidence from the GP analysis of the RV data with simultaneous activity indices prefers a model without a second Keplerian, therefore negating the existence of planet c.

Published
2022

123. MOA-2019-BLG-008Lb: A New Microlensing Detection of an Object at the Planet/Brown Dwarf Boundary

Author

Bachelet, E., primary, Tsapras, Y., additional, Gould, Andrew, additional, Street, R. A., additional, Bennett, David P., additional, Hundertmark, M. P. G., additional, Bozza, V., additional, Bramich, D. M., additional, Cassan, A., additional, Dominik, M., additional, Horne, K., additional, Mao, S., additional, Saha, A., additional, Wambsganss, J., additional, Zang, Weicheng, additional, Abe, Fumio, additional, Barry, Richard, additional, Bhattacharya, Aparna, additional, Bond, Ian A., additional, Fukui, Akihiko, additional, Fujii, Hirosane, additional, Hirao, Yuki, additional, Itow, Yoshitaka, additional, Kirikawa, Rintaro, additional, Kondo, Iona, additional, Koshimoto, Naoki, additional, Matsubara, Yutaka, additional, Matsumoto, Sho, additional, Miyazaki, Shota, additional, Muraki, Yasushi, additional, Olmschenk, Greg, additional, Ranc, Clément, additional, Okamura, Arisa, additional, Rattenbury, Nicholas J., additional, Satoh, Yuki, additional, Sumi, Takahiro, additional, Suzuki, Daisuke, additional, Silva, Stela Ishitani, additional, Toda, Taiga, additional, Tristram, Paul . J., additional, Vandorou, Aikaterini, additional, Yama, Hibiki, additional, Albrow, Michael D., additional, Chung, Sun-Ju, additional, Han, Cheongho, additional, Hwang, Kyu-Ha, additional, Jung, Youn Kil, additional, Ryu, Yoon-Hyun, additional, Shin, In-Gu, additional, Shvartzvald, Yossi, additional, Yee, Jennifer C., additional, Cha, Sang-Mok, additional, Kim, Dong-Jin, additional, Kim, Seung-Lee, additional, Lee, Chung-Uk, additional, Lee, Dong-Joo, additional, Lee, Yongseok, additional, Park, Byeong-Gon, additional, Pogge, Richard W., additional, Udalski, Andrzej, additional, Mróz, Przemek, additional, Poleski, Radosław, additional, Skowron, Jan, additional, Szymański, Michał K., additional, Soszyński, Igor, additional, Pietrukowicz, Paweł, additional, Kozłowski, Szymon, additional, Ulaczyk, Krzysztof, additional, Rybicki, Krzysztof A., additional, Iwanek, Patryk, additional, Wrona, Marcin, additional, and Gromadzki, Mariusz, additional

Published
2022
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124. Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035

Author

Herald, A, Udalski, A, Bozza, V, Rota, P, Bond, IA, Yee, JC, Sajadian, S, Mroz, P, Poleski, R, Skowron, J, Szymanski, MK, Soszynski, I, Pietrukowicz, P, Kozlowski, S, Ulaczyk, K, Rybicki, KA, Iwanek, P, Wrona, M, Gromadzki, M, Abe, F, Barry, R, Bennett, DP, Bhattacharya, A, Fukui, A, Fujii, H, Hirao, Y, Itow, Y, Kirikawa, R, Kondo, I, Koshimoto, N, Matsubara, Y, Matsumoto, S, Miyazaki, S, Muraki, Y, Olmschenk, G, Ranc, C, Okamura, A, Rattenbury, NJ, Satoh, Y, Sumi, T, Suzuki, D, Silva, SI, Toda, T, Tristram, PJ, Vandorou, A, Yama, H, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Gould, A, Henderson, CB, Johnson, S, Shvartzvald, Y, Zhu, W, Dominik, M, Hundertmark, M, Jorgensen, UG, Longa-Pena, P, Skottfelt, J, Tregloan-Reed, J, Bach-Moller, N, Burgdorf, M, D'Ago, G, Haikala, L, Hitchcock, J, Khalouei, E, Peixinho, N, Rahvar, S, Snodgrass, C, Southworth, J, Spyratos, P, Zang, W, Yang, H, Mao, S, Bachelet, E, Maoz, D, Street, RA, Tsapras, Y, Christie, GW, Cooper, T, de Almeida, L, Jr, DNJ-D, Green, J, Han, C, Hennerley, S, Marmont, A, McCormick, J, Monard, LAG, Natusch, T, Pogge, R, Collaboration, OGLE, Collaboration, MOA, Team, S, Consortium, M, Collaboration, LCOFUN, European Commission, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
GRAVITATIONAL LENS, FOS: Physical sciences, CHEMICAL EVOLUTION, Astrophysics::Cosmology and Extragalactic Astrophysics, GALACTIC BULGE, Q1, general [binaries], QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, PHOTOMETRY, low-mass [stars], QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), OPTICAL DEPTH, Astronomy and Astrophysics, 3rd-DAS, PLANET CANDIDATE, Astrophysics - Astrophysics of Galaxies, DIFFERENCE IMAGE-ANALYSIS, SPITZER, low mass [Stars], QC Physics, Astrophysics - Solar and Stellar Astrophysics, GIANT PLANETS, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), DISCOVERY, micro [gravitational lensing], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, brown dwarfs
Abstract

Context. Brown dwarfs are poorly understood transition objects between stars and planets, with several competing mechanisms having been proposed for their formation. Mass measurements are generally difficult for isolated objects but also for brown dwarfs orbiting low-mass stars, which are often too faint for spectroscopic follow-up. Aims. Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here we present the analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is due to a binary system composed of a brown dwarf orbiting a red dwarf. Methods. Thanks to extensive ground observations and the availability of space observations from Spitzer, it has been possible to obtain accurate estimates of all microlensing parameters, including parallax, source radius and orbital motion of the binary lens. Results. After accurate modeling, we find that the lens is composed of a red dwarf with mass $M_1 = 0.149 \pm 0.010M_\odot$ and a brown dwarf with mass $M_2 = 0.0463 \pm 0.0031M_\odot$, at a projected separation of $a_\perp = 0.585$ au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. Percent precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become common with the Roman space telescope., Comment: 13 pages, 6 figures

Published
2022

125. An isolated stellar-mass black hole detected through astrometric microlensing

Author

Sahu, KC, Anderson, J, Casertano, S, Bond, HE, Udalski, A, Dominik, M, Calamida, A, Bellini, A, Brown, TM, Rejkuba, M, Bajaj, V, Kains, N, Ferguson, HC, Fryer, CL, Yock, P, Mroz, P, Kozlowski, S, Pietrukowicz, P, Poleski, R, Skowron, J, Soszynski, I, Szymanski, MK, Ulaczyk, K, Wyrzykowski, L, Barry, R, Bennett, DP, Bond, IA, Hirao, Y, Silva, SI, Kondo, I, Koshimoto, N, Ranc, C, Rattenbury, NJ, Sumi, T, Suzuki, D, Tristram, PJ, Vandorou, A, Beaulieu, J-P, Marquette, J-B, Cole, A, Fouque, P, Hill, K, Dieters, S, Coutures, C, Dominis-Prester, D, Bennett, C, Bachelet, E, Menzies, J, Albrow, M, Pollard, K, Gould, A, Yee, J, Allen, W, Almeida, LA de, Christie, G, Drummond, J, Gal-Yam, A, Gorbikov, E, Jablonski, F, Lee, C-U, Maoz, D, Manulis, I, McCormick, J, Natusch, T, Pogge, RW, Shvartzvald, Y, Jorgensen, UG, Alsubai, KA, Andersen, MI, Bozza, V, Novati, SC, Hinse, TC, Hundertmark, M, Husser, T-O, Kerins, E, Longa-Pena, P, Mancini, L, Penny, M, Rahvar, S, Ricci, D, Sajadian, S, Skottfelt, J, Snodgrass, C, Southworth, J, Tregloan-Reed, J, Wambsganss, J, Wertz, O, Tsapras, Y, Street, RA, Bramich, DM, Horne, K, Steele, IA, STScI, PSU, Warsaw, Univ, Andrews, Univ St, ESO, Columbia, Univ, Lab, Los Alamos Nat, Auckland, Univ, Warwick, Univ, Centre, NASA Goddard Space Flight, Maryland, Univ, Univ, Massey, Univ, Osaka, America, Catholic Univ of, Heidelberg, Univ, Obs, Mt John, Zealand, New, Tasmania, Univ, Paris, IAP, Bordeaux, Univ, Toulouse, Univ, Japan, Nat Astron Obs, MIT, Obs, Las Cumbres, SAAO, Africa, South, Canterbury, Univ, Astronomy, Max-Planck-Inst for, Heidelberg, Univ, Ohio State, CfA, Cambridge, Obs, Vintage Lane, Norte, Univ Federal do Rio Grande do, Natal, Brazil, Mossoró, Obs, Auckland, Obs, Possum, Queensland, Univ Southern, Australia, Sci, Weizmann Inst of, Univ, Tel-Aviv, Israel, Espacias, Inst Nacional de Pesquisas, Astron, Korea, Inst, Space Sci, Sci, Weizmann Inst, Obs, Farm Cove, IRASR, Copenhagen, Univ, QEERI, Doha, Qatar, Denmark, Salerno, Univ, Italy, Napoli, INFN, IPAC, Pasadena, Toruń, Nicolaus Copernicus Univ, Univ, Chungnam Nat, Korea, South, Göttingen, Univ, Germany, Astroph, Jodrell Bank Centre, Manchester, Antofagasta, Univ, Rome, Univ, Turin, INAF, Univ, Louisiana State, Tech, Sharif Univ of, Tehran, Padova, INAF, Tech, Isfahan Univ, Univ, Open, Keynes, Milton, Edinburgh, Univ, Univ, Keele, Atacama, Univ, Chile, Liège, Univ, Dhabi, NY Univ Abu, Univ, Liverpool John Moores, Collaboration, OGLE, Collaboration, MOA, Collaboration, PLANET, Collaboration, microFUN, Consortium, MiNDSTEp, Collaboration, RoboNet, ITA, USA, GBR, European Commission, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, 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), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and ANR-18-CE31-0002,COLD-WORLDS,Statistiques des planètes proches de leur lieu de formation et leur distribution dans le disque et la barre de notre Galaxie(2018)

Subjects
GRAVITATIONAL LENS, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, PARALLAX, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, EVENTS, Black holes, 162, 672, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Solar and Stellar Astrophysics, PHOTOMETRY, QB Astronomy, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, QB, High Energy Astrophysical Phenomena (astro-ph.HE), MCC, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], STAR, Settore FIS/05, Astronomy and Astrophysics, BINARY, 3rd-DAS, EVOLUTION, QC Physics, DEFLECTION, RESOLUTION, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Block holes, PLANETS
Abstract

We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E~270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of six years, reveals a clear relativistic astrometric deflection of the background star's apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of the Earth's motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 +/- 1.3 Msun and a distance of 1.58 +/- 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic-disk stars at similar distances by an amount corresponding to a transverse space velocity of ~45 km/s, suggesting that the BH received a 'natal kick' from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial-velocity measurements of Galactic X-ray binaries, and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique., 37 pages, Published in ApJ

Published
2022

126. Detailed stellar activity analysis and modelling of GJ 832: Reassessment of the putative habitable zone planet GJ 832c

Author

Ministerio de Ciencia e Innovación (España), European Commission, Gorrini, P., Astudillo-Defru, N., Dreizler, S., Damasso, M., Díaz, R. F., Bonfils, Xavier, Jeffers, Sandra V., Barnes, John R., Del Sordo, F., Almenara, J. -M., Artigau, E., Bouchy, F., Charbonneau, D., Delfosse, X., Doyon, R., Figueira, P., Forveille, T., Haswell, C. A., López González, Maria J., Melo, C., Mennickent, R. E., Gaisné, G., Morales, Nicolás, Murgas, F., Pepe, F., Rodríguez Martínez, Eloy, Santos, N. C., Tal-Or, L., Tsapras, Y., Udry, Stephane, Ministerio de Ciencia e Innovación (España), European Commission, Gorrini, P., Astudillo-Defru, N., Dreizler, S., Damasso, M., Díaz, R. F., Bonfils, Xavier, Jeffers, Sandra V., Barnes, John R., Del Sordo, F., Almenara, J. -M., Artigau, E., Bouchy, F., Charbonneau, D., Delfosse, X., Doyon, R., Figueira, P., Forveille, T., Haswell, C. A., López González, Maria J., Melo, C., Mennickent, R. E., Gaisné, G., Morales, Nicolás, Murgas, F., Pepe, F., Rodríguez Martínez, Eloy, Santos, N. C., Tal-Or, L., Tsapras, Y., and Udry, Stephane

Abstract

Context. Gliese-832 (GJ 832) is an M2V star hosting a massive planet on a decade-long orbit, GJ 832b, discovered by radial velocity (RV). Later, a super Earth or mini-Neptune orbiting within the stellar habitable zone was reported (GJ 832c). The recently determined stellar rotation period (45.7 ± 9.3 days) is close to the orbital period of putative planet c (35.68 ± 0.03 days). Aims. We aim to confirm or dismiss the planetary nature of the RV signature attributed to GJ 832c, by adding 119 new RV data points, new photometric data, and an analysis of the spectroscopic stellar activity indicators. Additionally, we update the orbital parameters of the planetary system and search for additional signals. Methods. We performed a frequency content analysis of the RVs to search for periodic and stable signals. Radial velocity time series were modelled with Keplerians and Gaussian process (GP) regressions alongside activity indicators to subsequently compare them within a Bayesian framework. Results. We updated the stellar rotational period of GJ 832 from activity indicators, obtaining 37.5+1.4-1.5 days, improving the precision by a factor of 6. The new photometric data are in agreement with this value. We detected an RV signal near 18 days (FAP < 4.6%), which is half of the stellar rotation period. Two Keplerians alone fail at modelling GJ 832b and a second planet with a 35-day orbital period. Moreover, the Bayesian evidence from the GP analysis of the RV data with simultaneous activity indices prefers a model without a second Keplerian, therefore negating the existence of planet c. © P. Gorrini et al. 2022.

Published
2022

127. OGLE-2019-BLG-0033/MOA-2019-BLG-035

Author

Herald, A., Udalski, A., Bozza, V., Rota, P., Bond, I. A., Yee, J. C., Sajadian, S., Mróz, P., Poleski, R., Skowron, J., Szymański, M. K., Soszyński, I., Pietrukowicz, P., Kozłowski, S., Ulaczyk, K., Rybicki, K. A., Iwanek, P., Wrona, M., Gromadzki, M., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Fukui, A., Fujii, H., Hirao, Y., Itow, Y., Kirikawa, R., Kondo, I., Koshimoto, N., Matsubara, Y., Matsumoto, S., Miyazaki, S., Muraki, Y., Olmschenk, G., Ranc, C., Okamura, A., Rattenbury, N. J., Satoh, Y., Sumi, T., Suzuki, D., Silva, S. Ishitani, Toda, T., Tristram, P. J., Vandorou, A., Yama, H., Beichman, C. A., Bryden, G., Novati, S. Calchi, Carey, S., Gaudi, B. S., Gould, A., Henderson, C. B., Johnson, S., Shvartzvald, Y., Zhu, W., Dominik, M., Hundertmark, M., Jørgensen, U. G., Longa-Peña, P., Skottfelt, J., Tregloan-Reed, J., Bach-Møller, N., Burgdorf, M., D’Ago, G., Haikala, L., Hitchcock, J., Khalouei, E., Peixinho, N., Rahvar, S., Snodgrass, C., Southworth, J., Spyratos, P., Zang, W., Yang, H., Mao, S., Bachelet, E., Maoz, D., Street, R. A., Tsapras, Y., Christie, G. W., Cooper, T., de Almeida, L., do Nascimento, J.-D., Green, J., Han, C., Hennerley, S., Marmont, A., McCormick, J., Monard, L. A. G., Natusch, T., and Pogge, R.

Subjects
binaries: general, stars: low-mass, gravitational lensing: micro, brown dwarfs
Abstract

Context Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up. \ud \ud Aims Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here, we present an analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is caused by a binary system composed of a brown dwarf orbiting a red dwarf. \ud \ud Methods Thanks to extensive ground observations and the availability of space observations from Spitzer, it has been possible to obtain accurate estimates of all microlensing parameters, including the parallax, source radius, and orbital motion of the binary lens. \ud \ud Results Following an accurate modeling process, we found that the lens is composed of a red dwarf with a mass of M1 = 0.149 ± 0.010 M⊙ and a brown dwarf with a mass of M2 = 0.0463 ± 0.0031 M⊙at a projected separation of a⊥ = 0.585 au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. A percent-level precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become more common in the future thanks to the Roman space telescope.

Published
2022

128. A spectroscopic follow-up for Gaia19bld

Author

Bachelet, E., primary, Zieliński, P., additional, Gromadzki, M., additional, Gezer, I., additional, Rybicki, K., additional, Kruszyńska, K., additional, Ihanec, N., additional, Wyrzykowski, Ł., additional, Street, R. A., additional, Tsapras, Y., additional, Hundertmark, M., additional, Cassan, A., additional, Harbeck, D., additional, and Rabus, M., additional

Published
2021
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129. Single-lens mass measurement in the high-magnification microlensing event Gaia19bld located in the Galactic disc

Author

Rybicki, K. A., primary, Wyrzykowski, Ł., additional, Bachelet, E., additional, Cassan, A., additional, Zieliński, P., additional, Gould, A., additional, Calchi Novati, S., additional, Yee, J. C., additional, Ryu, Y.-H., additional, Gromadzki, M., additional, Mikołajczyk, P., additional, Ihanec, N., additional, Kruszyńska, K., additional, Hambsch, F.-J., additional, Zoła, S., additional, Fossey, S. J., additional, Awiphan, S., additional, Nakharutai, N., additional, Lewis, F., additional, Olivares E., F., additional, Hodgkin, S., additional, Delgado, A., additional, Breedt, E., additional, Harrison, D. L., additional, van Leeuwen, M., additional, Rixon, G., additional, Wevers, T., additional, Yoldas, A., additional, Udalski, A., additional, Szymański, M. K., additional, Soszyński, I., additional, Pietrukowicz, P., additional, Kozłowski, S., additional, Skowron, J., additional, Poleski, R., additional, Ulaczyk, K., additional, Mróz, P., additional, Iwanek, P., additional, Wrona, M., additional, Street, R. A., additional, Tsapras, Y., additional, Hundertmark, M., additional, Dominik, M., additional, Beichman, C., additional, Bryden, G., additional, Carey, S., additional, Gaudi, B. S., additional, Henderson, C., additional, Shvartzvald, Y., additional, Zang, W., additional, Zhu, W., additional, Christie, G. W., additional, Green, J., additional, Hennerley, S., additional, McCormick, J., additional, Monard, L. A. G., additional, Natusch, T., additional, Pogge, R. W., additional, Gezer, I., additional, Gurgul, A., additional, Kaczmarek, Z., additional, Konacki, M., additional, Lam, M. C., additional, Maskoliunas, M., additional, Pakstiene, E., additional, Ratajczak, M., additional, Stankeviciute, A., additional, Zdanavicius, J., additional, and Ziółkowska, O., additional

Published
2021
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130. Single lens mass measurement in the high magnification microlensing event Gaia19bld located in the Galactic Disk

Author

Rybicki, K.A., Wyrzykowski, Ł., Bachelet, E., Cassan, A., Zieliński, P., Gould, A., Calchi Novati, S., Yee, J.C., Ryu, Y.-H., Gromadzki, M., Mikołayczyk, P., Ihanec, N., Kruszyńska, K., Hambsch, F.-J., Zola, S., Fossey, S.J., Awiphan, S., Nakharutai, N., Lewis, F., Olivares E., F., Hodgkin, S., Delgado, A., Breedt, E., Harrison, D.L., van Leeuwen, M., Rixon, G., Wevers, T., Yoldas, A., Udalski, A., Szymański, M.K., Soszyński, I., Pietrokowicz, P., Kozłowski, S., Skowron, J., Poleski, R., Ulaczyk, K., Mróz, P., Iwanek, P., Wrona, M., Street, R.A., Tsapras, Y., Hundertmark, M., Dominik, Martin, Beichman, C., Bryden, G., Carey, S., Gaudi, B.S., Henderson, C., Shvartzwald, Y., Zang, W., Zhu, W., Christie, G.W., Green, J., Hennerley, S., McCormick, J., Monard, L.A.G., Natusch, T., Pogge, R.W., Gezer, I., Gurgul, A., Kaczmarek, Z., Lam, M.C., Maskoliunas, M., Pakstiene, E., Stankeviciute, A., Zdanavicius, J., Ziółkowska, O., European Commission, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
QC Physics, Stellar remnants, Microlensing, NDAS, QB Astronomy, QC, QB
Abstract

Funding: This work was supported from the Polish NCN grants: Preludium No. 2017/25/N/ST9/01253, Harmonia No. 2018/30/M/ST9/00311, MNiSW grant DIR/WK/2018/12, Daina No. 2017/27/L/ST9/03221, and by the Research Council of Lithuania, grant No. S-LL-19-2. . The OGLE project has received funding from the NCN grant MAESTRO 2014/14/A/ST9/00121 to AU. We acknowledge the European Commission’s H2020 OPTICON grant No. 730890. YT acknowledges the support of DFG priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets" (WA 1047/11-1). EB and RS gratefully acknowledge support from NASA grant 80NSSC19K0291. Work by AG was supported by JPL grant 1500811. Work by JCY was supported by JPL grant 1571564. SJF thanks Telescope Live for access to their telescope network. NN acknowledges the support of Data Science Research Center, Chiang Mai University. F.O.E. acknowledges support from the FONDECYT grant nr. 1201223. Context. Microlensing gives a unique opportunity to detect non-luminous objects. In the rare cases that the Einstein radius θ_E and microlensing parallax π_E can be measured, it is possible to determine the mass of the lens. With technological advances in both ground and space-based observatories, astrometric and interferometric measurements are becoming viable, which can lead to the more routine determination of θE and, if the microlensing parallax is also measured, the mass of the lens. Aims. We present the photometric analysis of Gaia19bld, a high magnification (A ≈ 60) microlensing event located in the southern Galactic plane, which exhibited finite source and microlensing parallax effects. Due to a prompt detection by the Gaia satellite and the very high brightness of I = 9.05 mag at the peak, it was possible to collect a complete and unique set of multi-channel follow-up observations, which allowed us to determine all parameters vital for the characterisation of the lens and the source in the microlensing event. Methods. Gaia19bld was discovered by the Gaia satellite and was subsequently densely followed-up with a network of ground based observatories and the Spitzer Space Telescope. We collected multiple high resolution spectra with VLT/X-Shooter to characterise the source star. The event was also observed with VLTI/PIONIER during the peak. Here we focus on the photometric observations and model the light curve composed of data from Gaia, Spitzer and multiple optical, ground-based observatories. We find the best fitting solution with parallax and finite source effects. We derive the limit on the luminosity of the lens based on the blended light model and spectroscopic distance. Results. We compute the mass of the lens to be 1.13 ± 0.03 M⊙ and derive its distance to be 5.52−0.64+0.35 kpc. The lens is likely a main sequence star, however its true nature has yet to be verified by the future high resolution observations. Our results are consistent with interferometric measurements of the angular Einstein radius, emphasising that interferometry can be a new channel for determining the masses of objects that would otherwise remain undetectable, including stellar-mass black holes. Postprint

Published
2021

131. OGLE-2018-BLG-1185b: A Low-mass Microlensing Planet Orbiting a Low-mass Dwarf

Author

Kondo, Iona, primary, Yee, Jennifer C., additional, Bennett, David P., additional, Sumi, Takahiro, additional, Koshimoto, Naoki, additional, Bond, Ian A., additional, Gould, Andrew, additional, Udalski, Andrzej, additional, Shvartzvald, Yossi, additional, Jung, Youn Kil, additional, Zang, Weicheng, additional, Bozza, Valerio, additional, Bachelet, Etienne, additional, Hundertmark, Markus P. G., additional, Rattenbury, Nicholas J., additional, Abe, F., additional, Barry, R., additional, Bhattacharya, A., additional, Donachie, M., additional, Fukui, A., additional, Fujii, H., additional, Hirao, Y., additional, Silva, S. Ishitani, additional, Itow, Y., additional, Kirikawa, R., additional, Li, M. C. A., additional, Matsubara, Y., additional, Miyazaki, S., additional, Muraki, Y., additional, Olmschenk, G., additional, Ranc, C., additional, Satoh, Y., additional, Shoji, H., additional, Suzuki, D., additional, Tanaka, Y., additional, Tristram, P. J., additional, Yamawaki, T., additional, Yonehara, A., additional, Mróz, P., additional, Poleski, R., additional, Skowron, J., additional, Szymański, M. K., additional, Soszyński, I., additional, Kozłowski, S., additional, Pietrukowicz, P., additional, Ulaczyk, K., additional, Rybicki, K. A., additional, Iwanek, P., additional, Wrona, M., additional, Albrow, M. D., additional, Chung, S.-J., additional, Han, C., additional, Hwang, K.-H., additional, Kim, H.-W., additional, Shin, I.-G., additional, Cha, S.-M., additional, Kim, D.-J., additional, Kim, S.-L., additional, Lee, C.-U., additional, Lee, D.-J., additional, Lee, Y., additional, Park, B.-G., additional, Pogge, R. W., additional, Ryu, Y.-H., additional, Beichman, C. A., additional, Bryden, G., additional, Novati, S. Calchi, additional, Carey, S., additional, Gaudi, B. S., additional, Henderson, C. B., additional, Zhu, W., additional, Maoz, D., additional, Penny, M. T., additional, Dominik, M., additional, Jørgensen, U. G., additional, Longa-Peña, P., additional, Peixinho, N., additional, Sajadian, S., additional, Skottfelt, J., additional, Snodgrass, C., additional, Tregloan-Reed, J., additional, Burgdorf, M. J., additional, Campbell-White, J., additional, Dib, S., additional, Fujii, Y. I., additional, Hinse, T. C., additional, Khalouei, E., additional, Rahvar, S., additional, Rabus, M., additional, Southworth, J., additional, Tsapras, Y., additional, Street, R. A., additional, Bramich, D. M., additional, Cassan, A., additional, Horne, K., additional, Wambsganss, J., additional, Mao, S., additional, and Saha, A., additional

Published
2021
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132. Discovery of a Jupiter/Saturn analog with gravitational microlensing

Author

Gaudi, B.S., Bennett, D.P., Udalski, A., Gould, A., Christie, G.W., Maoz, D., Dong, S., McCormick, J., Szymanski, M.K., Tristram, P.J., Nikolaev, S., Paczynski, B., Kubiak, M., Pietrzynski, G., Soszynski, I., Szewczyk, O., Ulaczyk, K., Wyrzykowski, L., DePoy, D.L., Han, C., Kaspi, S., Lee, C.-U., Mallia, F., Natusch, T., Pogge, R.W., Park, B.-G., Abe, F., Bond, I.A., Botzler, C.S., Fukui, A., Hearnshaw, J.B., Itow, Y., Kamiya, K., Korpela, A.V., Kilmartin, P.M., Lin, W, Masuda, K., Matsubara, Y., Motomura, M., Muraki, Y., Nakamura, S., Okumura, T., Ohnishi, K., Rattenbury, N.J., Sako, T., Saito, To., Sato, S., Skuljan, L., Sullivan, D.J., Sumi, T., Sweatman, W.L., Yock, P.C.M., Albrow, M.D., Allan, A., Beaulieu, J.-P., Burgdorf, M.J., Cook, K.H., Coutures, C., Dominik, M., Dieters, S., Fouque, P., Greenhill, J., Horne, K., Steele, I., Tsapras, Y., Chaboyer, B., Crocker, A., Frank, S., and Macintosh, B.

Subjects
Extrasolar planets -- Discovery and exploration, Gravitational lenses -- Observations
Published
2008

133. 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

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

Author

Wyrzykowski, Ł. Mróz, P. Rybicki, K.A. Gromadzki, M. Kołaczkowski, Z. Zieliński, M. Zieliński, P. Britavskiy, N. Gomboc, A. Sokolovsky, K. Hodgkin, S.T. Abe, L. Aldi, G.F. Almannaei, A. Altavilla, G. Al Qasim, A. Anupama, G.C. Awiphan, S. Bachelet, E. Baklş, V. Baker, S. Bartlett, S. Bendjoya, P. Benson, K. Bikmaev, I.F. Birenbaum, G. Blagorodnova, N. Blanco-Cuaresma, S. Boeva, S. Bonanos, A.Z. Bozza, V. Bramich, D.M. Bruni, I. Burenin, R.A. Burgaz, U. Butterley, T. Caines, H.E. Caton, D.B. Calchi Novati, S. Carrasco, J.M. Cassan, A. Epas, 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.H.J. Dennefeld, M. Dhillon, V.S. Dominik, M. Dziedzic, J. Erece, O. Eselevich, M.V. Esenoglu, H. Eyer, L. Figuera Jaimes, R. Fossey, S.J. Galeev, A.I. Grebenev, S.A. Gupta, A.C. Gutaev, A.G. Hallakoun, N. Hamanowicz, A. Han, C. Handzlik, B. Haislip, J.B. Hanlon, L. Hardy, L.K. Harrison, D.L. Van Heerden, H.J. Hoette, V.L. Horne, K. Hudec, R. Hundertmark, M. Ihanec, N. Irtuganov, E.N. Itoh, R. Iwanek, P. Jovanovic, M.D. Janulis, R. Jelínek, M. Jensen, E. Kaczmarek, Z. Katz, D. Khamitov, I.M. Kilic, Y. Klencki, J. Kolb, U. Kopacki, G. Kouprianov, V.V. Kruszyńska, K. Kurowski, S. Latev, G. Lee, C.-H. Leonini, S. Leto, G. Lewis, F. Li, Z. Liakos, A. Littlefair, S.P. Lu, J. Manser, C.J. Mao, S. Maoz, D. Martin-Carrillo, A. Marais, J.P. Maskoliūnas, M. Maund, J.R. Meintjes, P.J. Melnikov, S.S. Ment, K. Mikołajczyk, P. Morrell, M. Mowlavi, N. Mo Dzierski, D. Murphy, D. Nazarov, S. Netzel, H. Nesci, R. Ngeow, C.-C. Norton, A.J. Ofek, E.O. Pakštienė, E. Palaversa, L. Pandey, A. Paraskeva, E. Pawlak, M. Penny, M.T. Penprase, B.E. Piascik, A. Prieto, J.L. Qvam, J.K.T. Ranc, C. Rebassa-Mansergas, A. Reichart, D.E. Reig, P. Rhodes, L. Rivet, J.-P. Rixon, G. Roberts, D. Rosi, P. Russell, D.M. Zanmar Sanchez, R. Scarpetta, G. Seabroke, G. Shappee, B.J. Schmidt, R. Shvartzvald, Y. Sitek, M. Skowron, J. Niegowska, M. Snodgrass, C. Soares, P.S. Van Soelen, B. Spetsieri, Z.T. Stankevičiūtė, A. Steele, I.A. Street, R.A. Strobl, J. Strubble, E. Szegedi, H. Tinjaca Ramirez, L.M. Tomasella, L. Tsapras, Y. Vernet, D. Villanueva, S. Vince, O. Wambsganss, J. Van Der Westhuizen, I.P. Wiersema, K. Wium, D. Wilson, R.W. Yoldas, A. Zhuchkov, R.Y. Zhukov, D.G. Zdanavičius, J. Zoła, S. Zubareva, A.

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
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? 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. © ESO 2020.

Published
2020

135. OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk

Author

Hirao, Y, Bennett, DP, Ryu, Y-H, Koshimoto, N, Udalski, A, Yee, JC, Sumi, T, Bond, IA, Shvartzvald, Y, Abe, F, Barry, RK, Bhattacharya, A, Donachie, M, Fukui, A, Itow, Y, Kondo, I, Li, MCA, Matsubara, Y, Matsuo, T, Miyazaki, S, Muraki, Y, Nagakane, M, Ranc, C, Rattenbury, NJ, Suematsu, H, Shibai, H, Suzuki, D, Tristram, PJ, Yonehara, A, Skowron, J, Poleski, R, Mroz, P, Szymanski, MK, Soszynski, I, Kozlowski, S, Pietrukowicz, P, Ulaczyk, K, Rybicki, K, Iwanek, P, Albrow, MD, Chung, S-J, Gould, A, Han, C, Hwang, K-H, Jung, YK, Shin, I-G, Zang, W, Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y, Park, B-G, Pogge, RW, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Henderson, CB, Zhu, W, Bachelet, E, Bolt, G, Christie, G, Hundertmark, M, Natusch, T, Maoz, D, McCormick, J, Street, RA, Tan, T-G, Tsapras, Y, Jorgensen, UG, Dominik, M, Bozza, V, Skottfelt, J, Snodgrass, C, Ciceri, S, Jaimes, RF, Evans, DF, Peixinho, N, Hinse, TC, Burgdorf, MJ, Southworth, J, Rahvar, S, Sajadian, S, Rabus, M, von Essen, C, Fujii, YI, Campbell-White, J, Lowry, S, Helling, C, Mancini, L, Haikala, L, Kandori, R, Collaboration, MOA, Collaboration, OGLE, Collaboration, K, Team, S, Teams, LCOFF-U, Collaboration, M, Team, IRSF, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
010504 meteorology & atmospheric sciences, GRAVITATIONAL LENSING EXPERIMENT, Astrophysics, 01 natural sciences, JUPITER/SATURN ANALOG, Bulge, Planet, Saturn, QB Astronomy, 010303 astronomy & astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, education.field_of_study, Settore FIS/05, LUMINOSITY-RELATION, INTERSTELLAR EXTINCTION LAW, Astrophysics - Solar and Stellar Astrophysics, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, Proper motion, astro-ph.SR, astro-ph.GA, Population, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Gravitational microlensing exoplanet detection, EVENTS, SYSTEMS, 0103 physical sciences, PHOTOMETRY, DETERMINISTIC MODEL, education, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astronomy and Astrophysics, Mass ratio, Light curve, Astrophysics - Astrophysics of Galaxies, QC Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), astro-ph.EP, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the ${\it Spitzer}$ satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of $q=7.0 \times 10^{-4}$ from the light-curve modeling. The ground-only and ${\it Spitzer}$-"only" data each provide very strong one-dimensional (1-D) constraints on the 2-D microlens parallax vector $\bf{\pi_{\rm E}}$. When combined, these yield a precise measurement of $\bf{\pi_{\rm E}}$, and so of the masses of the host $M_{\rm host}=0.56\pm0.07\,M_\odot$ and planet $M_{\rm planet} = 0.41 \pm 0.05\,M_{\rm Jup}$. The system lies at a distance $D_{\rm L}=5.2 \pm 0.5 \ {\rm kpc}$ from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is $a_{\perp} = 3.5 \pm 0.3 \ {\rm au}$, i.e., just over twice the snow line. The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the ${\it Gaia}$ proper-motion measurement of the source suffers from a catastrophic $10\,\sigma$ error., Comment: 40 pages, 12 figures, 10 tables, accepted for publication in The Astronomical Journal

Published
2020

136. 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, Kains, N, Snodgrass, C, Steele, I. A, Andersen, J. M, Novati, S. Calchi, Diehl, C, 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, 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, Ch, Dieters, S, Prester, D. Dominis, Donatowicz, J, Fouqu, 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, Gaudi, B. S, Henderson, C. B, Hwang, K. H, Jung, Y. K, Kavka, A, Koo, J.-R, Lee, C.-U, Maoz, D, Natusch, T, Ngan, H, Park, H, Pogge, R. W, Shin, I. G, Shvartzvald, Y, 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, To, Sullivan, D. J, Sweatman, W. L, Suzuki, D, Tristram, P. J, Tsurumi, N, Wada, K, Yamai, N, Yock, P. C. M, and Yonehara, A

Subjects
Astronomy, 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 light curve, 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 plus or minus 0.43 M (sub J) planet orbiting a 0.44 plus or minus 0.07 solar mass early M-type star. The distance to the lens is 4.97 plus or minus 0.29 kpc and the projected separation between the host star and its planet at the time of the event is 3.45 plus or minus 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.

Published
2014
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138. Gaia 18dvy: A New FUor in the Cygnus OB3 Association

Author

Szegedi-Elek, E., primary, Ábrahám, P., additional, Wyrzykowski, Ł., additional, Kun, M., additional, Kóspál, Á., additional, Chen, L., additional, Marton, G., additional, Moór, A., additional, Kiss, C., additional, Pál, A., additional, Szabados, L., additional, Varga, J., additional, Varga-Verebélyi, E., additional, Andreas, C., additional, Bachelet, E., additional, Bischoff, R., additional, Bódi, A., additional, Breedt, E., additional, Burgaz, U., additional, Butterley, T., additional, Carrasco, J. M., additional, Čepas, V., additional, Damljanovic, G., additional, Gezer, I., additional, Godunova, V., additional, Gromadzki, M., additional, Gurgul, A., additional, Hardy, L., additional, Hildebrandt, F., additional, Hoffmann, S., additional, Hundertmark, M., additional, Ihanec, N., additional, Janulis, R., additional, Kalup, Cs., additional, Kaczmarek, Z., additional, Könyves-Tóth, R., additional, Krezinger, M., additional, Kruszyńska, K., additional, Littlefair, S., additional, Maskoliūnas, M., additional, Mészáros, L., additional, Mikołajczyk, P., additional, Mugrauer, M., additional, Netzel, H., additional, Ordasi, A., additional, Pakštienė, E., additional, Rybicki, K. A., additional, Sárneczky, K., additional, Seli, B., additional, Simon, A., additional, Šiškauskaitė, K., additional, Sódor, Á., additional, Sokolovsky, K. V., additional, Stenglein, W., additional, Street, R., additional, Szakáts, R., additional, Tomasella, L., additional, Tsapras, Y., additional, Vida, K., additional, Zdanavičius, J., additional, Zieliński, M., additional, Zieliński, P., additional, and Ziółkowska, O., additional

Published
2020
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139. OGLE-2013-BLG-0911Lb: A Secondary on the Brown-dwarf Planet Boundary around an M Dwarf

Author

Miyazaki, Shota, primary, Sumi, Takahiro, additional, Bennett, David P., additional, Udalski, Andrzej, additional, Shvartzvald, Yossi, additional, Street, Rachel, additional, Bozza, Valerio, additional, Yee, Jennifer C., additional, Bond, Ian A., additional, Rattenbury, Nicholas, additional, Koshimoto, Naoki, additional, Suzuki, Daisuke, additional, Fukui, Akihiko, additional, Abe, F., additional, Bhattacharya, A., additional, Barry, R., additional, Donachie, M., additional, Fujii, H., additional, Hirao, Y., additional, Itow, Y., additional, Kamei, Y., additional, Kondo, I., additional, Li, M. C. A., additional, Ling, C. H., additional, Matsubara, Y., additional, Matsuo, T., additional, Muraki, Y., additional, Nagakane, M., additional, Ohnishi, K., additional, Ranc, C., additional, Saito, T., additional, Sharan, A., additional, Shibai, H., additional, Suematsu, H., additional, Sullivan, D. J., additional, Tristram, P. J., additional, Yamakawa, T., additional, Yonehara, A., additional, Skowron, J., additional, Poleski, R., additional, Mróz, P., additional, Szymański, M. K., additional, Soszyński, I., additional, Pietrukowicz, P., additional, KozŁowski, S., additional, Ulaczyk, K., additional, Wyrzykowski, Ł., additional, Friedmann, Matan, additional, Kaspi, Shai, additional, Maoz, Dan, additional, Albrow, M., additional, Christie, G., additional, DePoy, D. L., additional, Gal-Yam, A., additional, Gould, A., additional, Lee, C.-U., additional, Manulis, I., additional, McCormick, J., additional, Natusch, T., additional, Ngan, H., additional, Pogge, R. W., additional, Porritt, I., additional, Tsapras, Y., additional, Bachelet, E., additional, Hundertmark, M. P. G., additional, Dominik, M., additional, Bramich, D. M., additional, Cassan, A., additional, Jaimes, R. Figuera, additional, Horne, K., additional, Schmidt, R., additional, Snodgrass, C., additional, Wambsganss, J., additional, Steele, I. A., additional, Menzies, J., additional, Mao, S., additional, Jørgensen, U. G., additional, Burgdorf, M. J., additional, Ciceri, S., additional, Novati, S. Calchi, additional, D’Ago, G., additional, Evans, D. F., additional, Hinse, T. C., additional, Kains, N., additional, Kerins, E., additional, Korhonen, H., additional, Mancini, L., additional, Popovas, A., additional, Rabus, M., additional, Rahvar, S., additional, Scarpetta, G., additional, Skottfelt, J., additional, Southworth, J., additional, Peixinho, N., additional, and Verma, P., additional

Published
2020
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140. Electromagnetic probes of primordial black holes as dark matter

Author

Kashlinsky, A., Ali-Haimoud, Y., Clesse, S., Garcia-Bellido, J., Wyrzykowski, L., Achucarro, A., Amendola, L., Annis, J., Arbey, A., Arendt, R. G., Atriobarandela, F., Bellomo, N., Belotsky, K., Bernal, J-L, Bird, S., Bozza, V., Byrnes, C., Calchi Novati, S., Calore, F., Carr, B. J., Chluba, J., Cholis, I., Cieplak, A., Cole, P., Dalianis, I., Davis, A-C, Davis, T., Luca, V., Dvorkin, I., Emparan, R., Ezquiaga, J-M, Fleury, P., Franciolini, G., Gaggero, D., Georg, J., Germani, C., Giudice, G-F, Goobar, A., Hasinger, G., Hector, A., Hundertmark, M., Hutsi, G., Jansen, R., Kamionkowski, M., Kawasaki, M., Kazanas, D., Kehagias, A., Khlopov, M., Knebe, A., Kohri, K., Koushiappas, S., Kovetz, E., Kuhnel, F., Macgibbon, J., Marzola, L., Mediavilla, E., Meszaros, P., Mroz, P., Munoz, J., Musco, I., Nesseris, S., Ozsoy, O., Pani, P., Poulin, V., Raccanelli, A., Racco, D., Raidal, M., Ranc, C., Rattenbury, N., Rhodes, J., Ricotti, M., Riotto, A., Rubin, S., Rubio, J., Ruiz-Morales, E., Sasaki, M., Schnittman, J., Shvartzvald, Y., Street, R., Takada, M., Takhistov, V., Tashiro, H., Tasinato, G., Tringas, G., Caner Unal, Tada, Y., Tsapras, Y., Vaskonen, V., Veermae, H., Vidotto, F., Watson, S., Windhorst, R., Yokoyama, S., Young, S., Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics and Astronomy, Cosmology and Nongalactic Astrophysics (astro-ph.CO), lens, Astrophysics::High Energy Astrophysical Phenomena, spin: 0, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, dark matter: density, galaxy: halo, star, accretion, supernova, quasar, LIGO, Astrophysics::Galaxy Astrophysics, pulsar, fluctuation, Astrophysics::Instrumentation and Methods for Astrophysics, stability, coherence, electromagnetic, X-ray: background, infrared, astro-ph.CO, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], black hole: primordial, Astrophysics - Cosmology and Nongalactic Astrophysics, cosmic background radiation: anisotropy
Abstract

The LIGO discoveries have rekindled suggestions that primordial black holes (BHs) may constitute part to all of the dark matter (DM) in the Universe. Such suggestions came from 1) the observed merger rate of the BHs, 2) their unusual masses, 3) their low/zero spins, and 4) also from the independently uncovered cosmic infrared background (CIB) fluctuations signal of high amplitude and coherence with unresolved cosmic X-ray background (CXB). Here we summarize the prospects to resolve this important issue with electromagnetic observations using the instruments and tools expected in the 2020's. These prospects appear promising to make significant, and potentially critical, advances. We demonstrate that in the next decade, new space- and ground-borne electromagnetic instruments, combined with concurrent theoretical efforts, should shed critical light on the long-considered link between primordial BHs and DM. Specifically the new data and methodologies under this program will involve: I) Probing with high precision the spatial spectrum of source-subtracted CIB with Euclid and WFIRST, and its coherence with unresolved cosmic X-ray background using eROSITA and Athena, II) Advanced searches for microlensing of Galactic stars by the intervening Galactic Halo BHs with OGLE, Gaia, LSST and WFIRST, III) Supernovae (SNe) lensing in the upcoming surveys with WFIRST, LSST and also potentially with Euclid and JWST, IV) Advanced theoretical work to understand the details of PBH accretion and evolution and their influence on cosmic microwave background (CMB) anisotropies in light of the next generation CMB experiments, V) Better new samples and theoretical understanding involving stability and properties of ultra faint dwarf galaxies, pulsar timing, and cosmological quasar lensing., Comment: Science whitepaper submitted to the Astro2020 Decadal Survey

Published
2019

141. OGLE-2018-BLG-0022: A Nearby M-dwarf Binary

Author

Street, R., Bachelet, E., Tsapras, Y., Hundertmark, M., Bozza, V., Dominik, M., Teams, M., Team, R., Bramich, D., Cassan, A., Horne, K., Mao, S., Saha, A., Wambsganss, J., Zang, W., Team, M., Jørgensen, U., Longa-Peña, P., Peixinho, N., Sajadian, S., Burgdorf, M., Campbell-White, J., Dib, S., Evans, D., Fujii, Y., Hinse, T., Khalouei, E., Lowry, S., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., and Tregloan-Reed, J.

Abstract

We report observations of the binary microlensing event OGLE-2018-BLG-0022, provided by the Robotic Observations of Microlensing Events (ROME)/Reactive Event Assessment (REA) Survey, which indicate that the lens is a low-mass binary star consisting of M3 (0.375 ± 0.020 M ☉) and M7 (0.098 ± 0.005 M ☉) components. The lens is unusually close, at 0.998 ± 0.047 kpc, compared with the majority of microlensing events, and despite its intrinsically low luminosity, it is likely that adaptive optics observations in the near future will be able to provide an independent confirmation of the lens masses.

Published
2019

142. OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing

Author

Li, S. -S., Zang, W., Udalski, A., Shvartzvald, Y., Huber, D., Lee, C. -U., Sumi, T., Gould, A., Mao, S., Fouque, P., Wang, T., Dong, S., Jorgensen, U. G., Cole, A., Mroz, P., Szymanski, M. K., Skowron, J., Poleski, R., Soszynski, I., Pietrukowicz, P., Kozlowski, S., Ulaczyk, K., Rybicki, K. A., Iwanek, P., Yee, J. C., Novati, S. Calchi, Beichman, C. A., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Zhu, W., Albrow, M. D., Chung, S. -J., Han, C., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Bond, I. A., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kondo, I., Koshimoto, N., Li, M. C. A., Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Ranc, C., Rattenbury, N. J., Suematsu, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Christie, G., Drummond, J., Green, J., Hennerley, S., Natusch, T., Porritt, I., Bachelet, E., Maoz, D., Street, R. A., Tsapras, Y., Bozza, V., Dominik, M., Hundertmark, M., Peixinho, N., Sajadian, S., Burgdorf, M. J., Evans, D. F., Jaimes, R. Figuera, Fujii, Y. I., Haikala, L. K., Helling, C., Henning, T., Hinse, T. C., Mancini, L., Longa-Pena, P., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., Unda-Sanzana, E., von Essen, C., Beaulieu, J. -P., Blackman, J., Hill, K., Li, S. -S., Zang, W., Udalski, A., Shvartzvald, Y., Huber, D., Lee, C. -U., Sumi, T., Gould, A., Mao, S., Fouque, P., Wang, T., Dong, S., Jorgensen, U. G., Cole, A., Mroz, P., Szymanski, M. K., Skowron, J., Poleski, R., Soszynski, I., Pietrukowicz, P., Kozlowski, S., Ulaczyk, K., Rybicki, K. A., Iwanek, P., Yee, J. C., Novati, S. Calchi, Beichman, C. A., Bryden, G., Carey, S., Gaudi, B. S., Henderson, C. B., Zhu, W., Albrow, M. D., Chung, S. -J., Han, C., Hwang, K. -H., Jung, Y. K., Ryu, Y. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Bond, I. A., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kondo, I., Koshimoto, N., Li, M. C. A., Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Ranc, C., Rattenbury, N. J., Suematsu, H., Sullivan, D. J., Suzuki, D., Tristram, P. J., Yonehara, A., Christie, G., Drummond, J., Green, J., Hennerley, S., Natusch, T., Porritt, I., Bachelet, E., Maoz, D., Street, R. A., Tsapras, Y., Bozza, V., Dominik, M., Hundertmark, M., Peixinho, N., Sajadian, S., Burgdorf, M. J., Evans, D. F., Jaimes, R. Figuera, Fujii, Y. I., Haikala, L. K., Helling, C., Henning, T., Hinse, T. C., Mancini, L., Longa-Pena, P., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., Unda-Sanzana, E., von Essen, C., Beaulieu, J. -P., Blackman, J., and Hill, K.

Published
2019

143. OGLE-2014-BLG-1186:gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?

Author

Dominik, M., Bachelet, E., Bozza, V., Street, R. A., Han, C., Hundertmark, M., Udalski, A., Bramich, D. M., Alsubai, K. A., Novati, S. Calchi, Ciceri, S., D'Ago, G., Jaimes, R. Figuera, Haugbolle, T., Hinse, T. C., Horne, K., Jorgensen, U. G., Juncher, D., Kains, N., Korhonen, H., Mancini, L., Menzies, J., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Schmidt, R., Skottfelt, J., Snodgrass, C., Southworth, J., Starkey, D., Steele, I. A., Surdej, J., Tsapras, Y., Wambsganss, J., Wertz, O., Pietrukowicz, P., Szymanski, M. K., Mroz, P., Skowron, J., Soszynski, I., Ulaczyk, K., Poleski, R., Wyrzykowski, L., Kozlowski, S., Dominik, M., Bachelet, E., Bozza, V., Street, R. A., Han, C., Hundertmark, M., Udalski, A., Bramich, D. M., Alsubai, K. A., Novati, S. Calchi, Ciceri, S., D'Ago, G., Jaimes, R. Figuera, Haugbolle, T., Hinse, T. C., Horne, K., Jorgensen, U. G., Juncher, D., Kains, N., Korhonen, H., Mancini, L., Menzies, J., Popovas, A., Rabus, M., Rahvar, S., Scarpetta, G., Schmidt, R., Skottfelt, J., Snodgrass, C., Southworth, J., Starkey, D., Steele, I. A., Surdej, J., Tsapras, Y., Wambsganss, J., Wertz, O., Pietrukowicz, P., Szymanski, M. K., Mroz, P., Skowron, J., Soszynski, I., Ulaczyk, K., Poleski, R., Wyrzykowski, L., and Kozlowski, S.

Published
2019

144. OGLE-2018-BLG-0022:A Nearby M-dwarf Binary

Author

Street, R. A., Bachelet, E., Tsapras, Y., Hundertmark, M. P. G., Bozza, V, Dominik, M., Bramich, D. M., Cassan, A., Horne, K., Mao, S., Saha, A., Wambsganss, J., Zang, Weicheng, Jorgensen, U. G., Longa-Pena, P., Peixinho, N., Sajadian, S., Burgdorf, M. J., Campbell-White, J., Dib, S., Evans, D. F., Fuji, Y., I, Hinse, T. C., Khalouel, E., Lowry, S., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., Tregloan-Reed, J., Street, R. A., Bachelet, E., Tsapras, Y., Hundertmark, M. P. G., Bozza, V, Dominik, M., Bramich, D. M., Cassan, A., Horne, K., Mao, S., Saha, A., Wambsganss, J., Zang, Weicheng, Jorgensen, U. G., Longa-Pena, P., Peixinho, N., Sajadian, S., Burgdorf, M. J., Campbell-White, J., Dib, S., Evans, D. F., Fuji, Y., I, Hinse, T. C., Khalouel, E., Lowry, S., Rahvar, S., Rabus, M., Skottfelt, J., Snodgrass, C., Southworth, J., and Tregloan-Reed, J.

Published
2019

145. First Assessment of the Binary Lens OGLE-2015-BLG-0232

Author

Bachelet, E., Bozza, V., Han, C., Udalski, A., Bond, I. A., Beaulieu, J. -P., Street, R. A., Kim, H. -I, Bramich, D. M., Cassan, A., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Mao, S., Menzies, J., Ranc, C., Schmidt, R., Snodgrass, C., Steele, I. A., Tsapras, Y., Wambsganss, J., Mroz, P., Soszynski, I., Szymanski, M. K., Skowron, J., Pietrukowicz, P., Kozlowski, S., Poleski, R., Ulaczyk, K., Pawlak, M., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Kondo, I., Koshimoto, N., Li, M. Cheung Alex, Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Rattenbury, N. J., Suematsu, H., Sullivan, D. J., Bachelet, E., Bozza, V., Han, C., Udalski, A., Bond, I. A., Beaulieu, J. -P., Street, R. A., Kim, H. -I, Bramich, D. M., Cassan, A., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Mao, S., Menzies, J., Ranc, C., Schmidt, R., Snodgrass, C., Steele, I. A., Tsapras, Y., Wambsganss, J., Mroz, P., Soszynski, I., Szymanski, M. K., Skowron, J., Pietrukowicz, P., Kozlowski, S., Poleski, R., Ulaczyk, K., Pawlak, M., Abe, F., Barry, R., Bennett, D. P., Bhattacharya, A., Donachie, M., Fukui, A., Hirao, Y., Itow, Y., Kawasaki, K., Kondo, I., Koshimoto, N., Li, M. Cheung Alex, Matsubara, Y., Muraki, Y., Miyazaki, S., Nagakane, M., Rattenbury, N. J., Suematsu, H., and Sullivan, D. J.

Published
2019

146. Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star

Author

Fukui, A., primary, Suzuki, D., additional, Koshimoto, N., additional, Bachelet, E., additional, Vanmunster, T., additional, Storey, D., additional, Maehara, H., additional, Yanagisawa, K., additional, Yamada, T., additional, Yonehara, A., additional, Hirano, T., additional, Bennett, D. P., additional, Bozza, V., additional, Mawet, D., additional, Penny, M. T., additional, Awiphan, S., additional, Oksanen, A., additional, Heintz, T. M., additional, Oberst, T. E., additional, Béjar, V. J. S., additional, Casasayas-Barris, N., additional, Chen, G., additional, Crouzet, N., additional, Hidalgo, D., additional, Klagyivik, P., additional, Murgas, F., additional, Narita, N., additional, Palle, E., additional, Parviainen, H., additional, Watanabe, N., additional, Kusakabe, N., additional, Mori, M., additional, Terada, Y., additional, Leon, J. P. de, additional, Hernandez, A., additional, Luque, R., additional, Monelli, M., additional, Montañes-Rodriguez, P., additional, Prieto-Arranz, J., additional, Murata, K. L., additional, Shugarov, S., additional, Kubota, Y., additional, Otsuki, C., additional, Shionoya, A., additional, Nishiumi, T., additional, Nishide, A., additional, Fukagawa, M., additional, Onodera, K., additional, Villanueva, S., additional, Street, R. A., additional, Tsapras, Y., additional, Hundertmark, M., additional, Kuzuhara, M., additional, Fujita, M., additional, Beichman, C., additional, Beaulieu, J.-P., additional, Alonso, R., additional, Reichart, D. E., additional, Kawai, N., additional, and Tamura, M., additional

Published
2019
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147. OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing

Author

Li, S-S, primary, Zang, W, primary, Udalski, A, primary, Shvartzvald, Y, primary, Huber, D, primary, Lee, C-U, primary, Sumi, T, primary, Gould, A, primary, Mao, S, primary, Fouqué, P, primary, Wang, T, primary, Dong, S, primary, Jørgensen, U G, primary, Cole, A, primary, Mróz, P, primary, Szymański, M K, primary, Skowron, J, primary, Poleski, R, primary, Soszyński, I, primary, Pietrukowicz, P, primary, Kozłowski, S, primary, Ulaczyk, K, primary, Rybicki, K A, primary, Iwanek, P, primary, Yee, J C, primary, Calchi Novati, S, primary, Beichman, C A, primary, Bryden, G, primary, Carey, S, primary, Gaudi, B S, primary, Henderson, C B, primary, Zhu, W, primary, Albrow, M D, primary, Chung, S-J, primary, Han, C, primary, Hwang, K-H, primary, Jung, Y K, primary, Ryu, Y-H, primary, Shin, I-G, primary, Cha, S-M, primary, Kim, D-J, primary, Kim, H-W, primary, Kim, S-L, primary, Lee, D-J, primary, Lee, Y, primary, Park, B-G, primary, Pogge, R W, primary, Bond, I A, primary, Abe, F, primary, Barry, R, primary, Bennett, D P, primary, Bhattacharya, A, primary, Donachie, M, primary, Fukui, A, primary, Hirao, Y, primary, Itow, Y, primary, Kondo, I, primary, Koshimoto, N, primary, Li, M C A, primary, Matsubara, Y, primary, Muraki, Y, primary, Miyazaki, S, primary, Nagakane, M, primary, Ranc, C, primary, Rattenbury, N J, primary, Suematsu, H, primary, Sullivan, D J, primary, Suzuki, D, primary, Tristram, P J, primary, Yonehara, A, primary, Christie, G, primary, Drummond, J, primary, Green, J, primary, Hennerley, S, primary, Natusch, T, primary, Porritt, I, primary, Bachelet, E, primary, Maoz, D, primary, Street, R A, primary, Tsapras, Y, primary, Bozza, V, primary, Dominik, M, primary, Hundertmark, M, primary, Peixinho, N, primary, Sajadian, S, primary, Burgdorf, M J, primary, Evans, D F, primary, Figuera Jaimes, R, primary, Fujii, Y I, primary, Haikala, L K, primary, Helling, C, primary, Henning, T, primary, Hinse, T C, primary, Mancini, L, primary, Longa-Peña, P, primary, Rahvar, S, primary, Rabus, M, primary, Skottfelt, J, primary, Snodgrass, C, primary, Southworth, J, primary, Unda-Sanzana, E, primary, von Essen, C, primary, Beaulieu, J-P, primary, Blackman, J, primary, and Hill, K, primary

Published
2019
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148. OGLE-2014-BLG-1186: gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?

Author

Dominik, M, primary, Bachelet, E, additional, Bozza, V, additional, Street, R A, additional, Han, C, additional, Hundertmark, M, additional, Udalski, A, additional, Bramich, D M, additional, Alsubai, K A, additional, Calchi Novati, S, additional, Ciceri, S, additional, D’Ago, G, additional, Figuera Jaimes, R, additional, Haugbølle, T, additional, Hinse, T C, additional, Horne, K, additional, Jørgensen, U G, additional, Juncher, D, additional, Kains, N, additional, Korhonen, H, additional, Mancini, L, additional, Menzies, J, additional, Popovas, A, additional, Rabus, M, additional, Rahvar, S, additional, Scarpetta, G, additional, Schmidt, R, additional, Skottfelt, J, additional, Snodgrass, C, additional, Southworth, J, additional, Starkey, D, additional, Steele, I A, additional, Surdej, J, additional, Tsapras, Y, additional, Wambsganss, J, additional, Wertz, O, additional, Pietrukowicz, P, additional, Szymański, M K, additional, Mróz, P, additional, Skowron, J, additional, Soszyński, I, additional, Ulaczyk, K, additional, Poleski, R, additional, Wyrzykowski, Ł, additional, and Kozłowski, S, additional

Published
2019
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149. OGLE-2016-BLG-1190Lb : The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Author

Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jorgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Mroz, P., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., 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., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To, Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., Bryden, G., Howell, S. B., Jacklin, S., Penny, M. T., Mao, S., Fouque, Pascal, Wang, T., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Li, Z., Cross, S., Cassan, A., Horne, K., Schmidt, R., Wambsganss, J., Ment, S. K., Maoz, D., Snodgrass, C., Steele, I. A., Bozza, V., Burgdorf, M. J., Ciceri, Simona, D'Ago, G., Evans, D. F., Hinse, T. C., Kerins, E., Kokotanekova, R., Longa, P., MacKenzie, J., Popovas, A., Rabus, M., Rahvar, S., Sajadian, S., Skottfelt, J., Southworth, J., von Essen, C., Ryu, Y. -H., Yee, J. C., Udalski, A., Bond, I. A., Shvartzvald, Y., Zang, W., Jaimes, R. Figuera, Jorgensen, U. G., Zhu, W., Huang, C. X., Jung, Y. K., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Hwang, K. -H., Shin, I. -G., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W., Novati, S. Calchi, Carey, S., Henderson, C. B., Beichman, C., Gaudi, B. S., Mroz, P., Poleski, R., Skowron, J., Szymanski, M. K., Soszynski, I., Kozlowski, S., Pietrukowicz, P., Ulaczyk, K., Pawlak, M., Abe, F., Asakura, Y., Barry, R., 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., Miyazaki, S., Muraki, Y., Nagakane, M., Ohnishi, K., Ranc, C., Rattenbury, N. J., Saito, To, Sharan, A., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, P. J., Yamada, T., Yonehara, A., Bryden, G., Howell, S. B., Jacklin, S., Penny, M. T., Mao, S., Fouque, Pascal, Wang, T., Street, R. A., Tsapras, Y., Hundertmark, M., Bachelet, E., Dominik, M., Li, Z., Cross, S., Cassan, A., Horne, K., Schmidt, R., Wambsganss, J., Ment, S. K., Maoz, D., Snodgrass, C., Steele, I. A., Bozza, V., Burgdorf, M. J., Ciceri, Simona, D'Ago, G., Evans, D. F., Hinse, T. C., Kerins, E., Kokotanekova, R., Longa, P., MacKenzie, J., Popovas, A., Rabus, M., Rahvar, S., Sajadian, S., Skottfelt, J., Southworth, J., and von Essen, C.

Abstract

We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the Galactic bulge/ bar, an assignation that can be confirmed by two epochs of high-resolution imaging of the combined source-lens baseline object. The planet's mass, M-p = 13.4 +/- 0.9 M-J, places it right at the deuteriumburning limit, i. e., the conventional boundary between planets and brown dwarfs. Its existence raises the question of whether such objects are really planets (formed within the disks of their hosts) or failed stars (lowmass objects formed by gas fragmentation). This question may ultimately be addressed by comparing disk and bulge/bar planets, which is a goal of the Spitzer microlens program. The host is a G dwarf, M-host = 0.89. +/- 0.07 M-circle dot, and the planet has a semimajor axis a similar to 2.0 au. We use Kepler K2 Campaign 9 microlensing data to break the lens-mass degeneracy that generically impacts parallax solutions from Earth-Spitzer observations alone, which is the first successful application of this approach. The microlensing data, derived primarily from near-continuous, ultradense survey observations from OGLE, MOA, and three KMTNet telescopes, contain more orbital information than for any previous microlensing planet, but not quite enough to accurately specify the full orbit. However, these data do permit the first rigorous test of microlensing orbital-motion measurements, which are typically derived from data taken over < 1% of an orbital period.

Published
2018
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150. The POINT-AGAPE survey — II. An unrestricted search for microlensing events towards M31

Author

Belokurov, V., An, J., Evans, N. W., Hewett, P., Baillon, P., Novati, S. Calchi, Carr, B. J., Creze, M., Giraud-Heraud, Y., Gould, A., Jetzer, Ph., Kaplan, J., Kerins, E., Paulin-Henriksson, S., Smartt, S. J., Stalin, C. S., Tsapras, Y., Weston, M. J., 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), AGAPE, 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), University of Zurich, Belokurov, V, 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, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics and Astronomy, 1912 Space and Planetary Science, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 530 Physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics (astro-ph), 3103 Astronomy and Astrophysics, FOS: Physical sciences, Astrophysics, 142-005 142-005
Abstract

An automated search is carried out for microlensing events using a catalogue of 44554 variable superpixel lightcurves derived from our three-year monitoring program of M31. Each step of our candidate selection is objective and reproducible by a computer. Our search is unrestricted, in the sense that it has no explicit timescale cut. So, it must overcome the awkward problem of distinguishing long-timescale microlensing events from long-period stellar variables. The basis of the selection algorithm is the fitting of the superpixel lightcurves to two different theoretical models, using variable star and blended microlensing templates. Only if microlensing is preferred is an event retained as a possible candidate. Further cuts are made with regard to (i) sampling, (ii) goodness of fit of the peak to a Paczynski curve, (iii) consistency of the microlensing hypothesis with the absence of a resolved source, (iv) achromaticity, (v) position in the colour-magnitude diagram and (vi) signal-to-noise ratio. Our results are reported in terms of first-level candidates, which are the most trustworthy, and second-level candidates, which are possible microlensing but have lower signal-to-noise and are more questionable. The pipeline leaves just 3 first-level candidates, all of which have very short full-width half-maximum timescale (, 22 pages, 18 figures, MNRAS, to appear

Published
2017

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