WorldWideScience

Sample records for caustic-crossing microlensing events

  1. Detecting stellar spots through polarimetry observations of microlensing events in caustic-crossing

    CERN Document Server

    Sajadian, Sedighe

    2015-01-01

    In this work, we investigate if gravitational microlensing can magnify the polarization signal of a stellar spot and make it be observable. A stellar spot on a source star of microlensing makes polarization signal through two channels of Zeeman effect and breaking circular symmetry of the source surface brightness due to its temperature contrast. We first explore the characteristics of perturbations in polarimetric microlensing during caustic-crossing of a binary lensing as follows: (a) The cooler spots over the Galactic bulge sources have the smaller contributions in the total flux, although they have stronger magnetic fields. (b) The maximum deviation in the polarimetry curve due to the spot happens when the spot is located near the source edge and the source spot is first entering the caustic whereas the maximum photometric deviation occurs for the spots located at the source center. (c) There is a (partial) degeneracy for indicating spot's size, its temperature contrast and its magnetic induction from the...

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

    CERN Document Server

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

    2012-01-01

    Despite astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of 2 binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax from analyses of the well-resolved caustic-crossing parts of the light curve and the long-term deviation induced by the orbital motion of the Earth around the Sun, respectively. The measured masses of the binary components are 0.43 $M_{\\odot}$ and 0.39 $M_{\\odot}$ for MOA-2011-BLG-090 and 0.57 $M_{\\odot}$ and 0.17 $M_{\\odot}$ for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011...

  3. STATISTICS OF MICROLENSING CAUSTIC CROSSINGS IN Q 2237+0305: PECULIAR VELOCITY OF THE LENS GALAXY AND ACCRETION DISK SIZE

    Energy Technology Data Exchange (ETDEWEB)

    Mediavilla, E. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna E-38200 Tenerife (Spain); Jimenez-Vicente, J. [Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus de Fuentenueva E-18071 Granada (Spain); Muñoz, J. A. [Departamento de Astronomía y Astrofísica, Universidad de Valencia E-46100 Burjassot, Valencia (Spain); Mediavilla, T.; Ariza, O. [Departamento de Estadística e Investigación Operativa, Universidad de Cádiz, Avda Ramón Puyol s/n E-11202, Algeciras, Cádiz (Spain)

    2015-01-10

    We use the statistics of caustic crossings induced by microlensing in the lens system Q 2237+0305 to study the lens galaxy peculiar velocity. We calculate the caustic crossing rates for a comprehensive family of stellar mass functions and find a dependence of the average number of caustic crossings with the effective transverse velocity and the average mass, 〈n〉∝v{sub eff}/√(〈m〉), equivalent to the theoretical prediction for the case of microlenses with identical masses. We explore the possibilities of the method to measure v {sub eff} using the ∼12 yr of Optical Gravitational Lensing Experiment monitoring of the four images of Q 2237+0305. To determine a lower limit for v {sub eff}, we count, conservatively, a single caustic crossing for each one of the four high magnification events identified in the literature (plus one additional proposed by us) obtaining v{sub eff}≳240√(〈m〉/0.17 M{sub ⊙}) km s{sup −1} at 68% of confidence. From this value and the average FWHM of the four high magnification events, we obtain a lower limit of r{sub s}≳1.4√(〈m〉/0.17 M{sub ⊙}) light-days for the radius of the source (r{sub s} = FWHM/2.35). Tentative identification of three additional caustic crossing events leads to estimates of v{sub eff}≃(493±246)√(〈m〉/0.17 M{sub ⊙}) km s{sup −1} for the effective transverse velocity and of r{sub s}≃(2.7±1.3)√(〈m〉/0.17 M{sub ⊙}) light-days for the source size. The estimated transverse peculiar velocity of the galaxy is v{sub t}≃(429±246)√(〈m〉/0.17 M{sub ⊙}) km s{sup −1}.

  4. Hard X-ray view of microlensing events in RX J1131-1231

    CERN Document Server

    Neronov, A; Walter, R

    2016-01-01

    RX J1131-1231 is a gravitationally lensed system which includes four images of a quasar lensed by an elliptical galaxy. The flux in the individual images is known to be affected by microlensing effect in the visible and X-ray bands. We study the multi-wavelength properties of RX J1131-1231 over a broad energy range, from optical to hard X-ray, during the periods of the microlensing caustic crossings. We aim to constrain the spatial extent of the X-ray emission region at different energies. We combine the data of the source monitoring in the visible band with the X-ray data of the Burst Alert Telescope (BAT) on board of SWIFT satellite and Chandra X-ray observatory. Inspecting the broad band spectrum and lightcurves of the source we identify several microlensing caustic crossing events, and study the details of variability of the source during these events. The caustic crossings of image A on MJD 55150 and 55500 produce strong variations of the overall X-ray flux from the source. In the soft X-ray band, the ca...

  5. Predictions for microlensing planetary events from core accretion theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wei; Mao, Shude [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Penny, Matthew; Gould, Andrew [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Gendron, Rieul, E-mail: weizhu@astronomy.ohio-state.edu [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom)

    2014-06-10

    We conduct the first microlensing simulation in the context of a planet formation model. The planet population is taken from the Ida and Lin core accretion model for 0.3 M {sub ☉} stars. With 6690 microlensing events, we find that for a simplified Korea Microlensing Telescopes Network (KMTNet), the fraction of planetary events is 2.9%, out of which 5.5% show multiple-planet signatures. The numbers of super-Earths, super-Neptunes, and super-Jupiters detected are expected to be almost equal. Our simulation shows that high-magnification events and massive planets are favored by planet detections, which is consistent with previous expectation. However, we notice that extremely high-magnification events are less sensitive to planets, which is possibly because the 10 minute sampling of KMTNet is not intensive enough to capture the subtle anomalies that occur near the peak. This suggests that while KMTNet observations can be systematically analyzed without reference to any follow-up data, follow-up observations will be essential in extracting the full science potential of very high magnification events. The uniformly high-cadence observations expected for KMTNet also result in ∼55% of all detected planets not being caustic crossing, and more low-mass planets even down to Mars mass being detected via planetary caustics. We also find that the distributions of orbital inclinations and planet mass ratios in multiple-planet events agree with the intrinsic distributions.

  6. Illuminating Hot Jupiters in caustic crossing

    CERN Document Server

    Sajadian, Sedighe

    2010-01-01

    In recent years a large number of Hot Jupiters orbiting in a very close orbit around the parent stars have been explored with the transit and doppler effect methods. Here in this work we study the gravitational microlensing effect of a binary lens on a parent star with a Hot Jupiter revolving around it. Caustic crossing of the planet makes enhancements on the light curve of the parent star in which the signature of the planet can be detected by high precision photometric observations. We use the inverse ray shooting method with tree code algorithm to generate the combined light curve of the parent star and the planet. In order to investigate the probability of observing the planet signal, we do a Monte-Carlo simulation and obtain the observational optical depth of $\\tau \\sim 10^{-8}$. We show that about ten years observations of Galactic Bulge with a network of telescopes will enable us detecting about ten Hot Jupiter with this method. Finally we show that the observation of the microlensing event in infra-re...

  7. Line Caustic Microlensing and Limb Darkening

    CERN Document Server

    Rhie, S H; Rhie, Sun Hong; Bennett, David P.

    1999-01-01

    In a line caustic crossing microlensing event, the caustic line moving across the surface of the source star provides a direct method to measure the integrated luminosity profile of the star. Combined with the enormous brightening at the caustic crossings, microlensing offers a promising tool for studying stellar luminosity profiles. We derive the amplification behavior of the two extra images that become partial images conjoined across the critical curve at a line caustic crossing. We identify the multiplicative factors that depend on the caustic crossing point and the relative size of the star, and the shape function that depends on the stellar luminosity profile. We examine the analytic limb-darkening models -- linear, square root, and square -- using the analytic form of the shape function. We find that the microlensing lightcurves must be determined to an accuracy of better than 0.3-0.8% in order to be able to determine the linear limb-darkening parameter $c_1$ with precision of binaries as reported by P...

  8. Characterizing low-mass binaries from observation of long-timescale caustic-crossing gravitational microlensing events

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Choi, J.-Y

    2012-01-01

    Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of phys...

  9. Gravitational Microlensing Events as a Target for the SETI project

    Science.gov (United States)

    Rahvar, Sohrab

    2016-09-01

    The detection of signals from a possible extrasolar technological civilization is one of the most challenging efforts of science. In this work, we propose using natural telescopes made of single or binary gravitational lensing systems to magnify leakage of electromagnetic signals from a remote planet that harbors Extraterrestrial Intelligent (ETI) technology. Currently, gravitational microlensing surveys are monitoring a large area of the Galactic bulge to search for microlensing events, finding more than 2000 events per year. These lenses are capable of playing the role of natural telescopes, and, in some instances, they can magnify radio band signals from planets orbiting around the source stars in gravitational microlensing systems. Assuming that the frequency of electromagnetic waves used for telecommunication in ETIs is similar to ours, we propose follow-up observation of microlensing events with radio telescopes such as the Square Kilometre Array (SKA), the Low Frequency Demonstrators, and the Mileura Wide-Field Array. Amplifying signals from the leakage of broadcasting by an Earth-like civilization will allow us to detect them as far as the center of the Milky Way galaxy. Our analysis shows that in binary microlensing systems, the probability of amplification of signals from ETIs is more than that in single microlensing events. Finally, we propose the use of the target of opportunity mode for follow-up observations of binary microlensing events with SKA as a new observational program for searching ETIs. Using optimistic values for the factors of the Drake equation provides detection of about one event per year.

  10. Resolving the Nature of the LMC Microlensing Event LMC-5

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A J; Cook, K H; Keller, S C

    2004-04-22

    The authors present the results from an analysis of Hubble Space Telescope High Resolution Camera data for the Large Magellanic Cloud microlensing event MACHO-LMC-5. By determining the parallax and proper motion of this object they find that the lens is an M dwarf star at a distance of 578{sub -53}{sup +65}pc with a proper motion of 21.39 {+-} 0.04 mas/yr. Based on the kinematics and location of this star is it more likely to be part of the Galactic thick disk than thin disk population. They confirm that the microlensing event LMC-5 is a jerk-parallax microlensing event.

  11. Gravitational Microlensing Events as a Target for SETI project

    CERN Document Server

    Rahvar, Sohrab

    2015-01-01

    Detection of signals from a possible extrasolar technological civilization is one of the challenging efforts of science. In this work, we propose using natural telescopes made of single or binary gravitational lensing systems to magnify leakage of electromagnetic signals from a remote planet harbours an Extra Terrestrial Intelligent (ETI) technology. The gravitational microlensing surveys are monitoring a large area of Galactic bulge for searching microlensing events and each year they find more than $2000$ events. These lenses are capable of playing the role of natural telescopes and in some occasions they can magnify signals from planets orbiting around the source stars in the gravitational microlensing systems. Assuming that frequency of electromagnetic waves used for telecommunication in ETIs is similar to ours, we propose follow-up observation of microlensing events with radio telescopes such as Square Kilometre Array (SKA), Low Frequency Demonstrators (LFD) and Mileura Wide-Field Array (MWA). Amplifying...

  12. Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined Data

    CERN Document Server

    Jeong, J; Han, C; Gould, A; Udalski, A; Szymański, M K; Pietrzyński, G; Soszyński, I; Poleski, R; Ulaczyk, K; Wyrzykowski, Ł; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Koshimoto, N; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Sweatman, W L; Sumi, T; Suzuki, D; Tristram, P J; Tsurumi, N; Wada, K; Yamai, N; Yock, P C M; Yonehara, A; Albrow, M D; Batista, V; Beaulieu, J -P; Caldwell, J A R; Cassan, A; Cole, A; Coutures, C; Dieters, S; Dominik, M; Prester, D Dominis; Donatowicz, J; Fouqué, P; Greenhill, J; Hoffman, M; Huber, M; Jørgensen, U G; Kane, S R; Kubas, D; Martin, R; Marquette, J -B; Menzies, J; Pitrou, C; Pollard, K; Sahu, K C; Vinter, C; Wambsganss, J; Williams, A; Allen, W; Bolt, G; Choi, J -Y; Christie, G W; DePoy, D L; Drummond, J; Gaudi, B S; Hwang, K -H; Jung, Y K; Lee, C -U; Mallia, F; Maoz, D; Maury, A; McCormick, J; Monard, L A G; Moorhouse, D; Natusch, T; Ofek, E O; Park, B -G; Pogge, R W; Santallo, R; Shin, I -G; Thornley, G; Yee, J C; Bramich, D M; Horne, K; Hundertmark, M; Kains, N; Snodgrass, C; Steele, I; Street, R; Tsapras, Y

    2015-01-01

    We reanalyze microlensing events in the published list of anomalous events that were observed from the OGLE lensing survey conducted during 2004-2008 period. In order to check the existence of possible degenerate solutions and extract extra information, we conduct analyses based on combined data from other survey and follow-up observation and consider higher-order effects. Among the analyzed events, we present analyses of 8 events for which either new solutions are identified or additional information is obtained. We find that the previous binary-source interpretations of 5 events are better interpreted by binary-lens models. These events include OGLE-2006-BLG-238, OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210. With additional data covering caustic crossings, we detect finite-source effects for 6 events including OGLE-2006-BLG-215, OGLE-2006-BLG-238, OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. Among them, we are able to measure the Einstein ...

  13. Matching microlensing events with X-ray sources

    CERN Document Server

    Sartore, N

    2011-01-01

    The detection of old neutron stars and black holes in isolation is one of the cornerstones of compact object astrophysics. Microlensing surveys may help on this purpose since the lensing mechanism is independent of the emission properties of the lens. Indeed, several black hole candidates deriving through microlensing observations have been reported in the literature. The identification of counterparts, especially in the X-rays, would be a strong argument in favor of the compact nature of these lenses. We perform a cross-correlation between the catalogs of microlensing events by the OGLE, MACHO and MOA teams, and those of X-rays sources from XMM-Newton and Chandra satellites. Based on our previous work, we select only microlensing events longer than 100 days, which should contain a large fraction of lenses as compact objects. Our matching criterion takes into account the positional coincidence in the sky. We find a single match between a microlensing event OGLE 2004-BLG-81 and the X-ray source 2XMM J180540.5-...

  14. Galactic Bulge Microlensing Events from the MACHO Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C L; Griest, K; Popowski, P; Cook, K H; Drake, A J; Minniti, D; Myer, D G; Alcock, C; Allsman, R A; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Freeman, K C; Geha, M; Lehner, M J; Marshall, S L; Nelson, C A; Peterson, B A; Quinn, P J; Stubbs, C W; Sutherland, W; Vandehei, T; Welch, D L

    2005-06-16

    The authors present a catalog of 450 relatively high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout the fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and they find evidence for substantial blending. In a companion paper they give optical depths for the sub-sample of events on clump giant source stars, where blending is a less significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. They also identify a number of contaminating background events as cataclysmic variable stars.

  15. Microlensing Events in Gaia and other Astrometric Surveys

    Science.gov (United States)

    Baker, Claire; Di Stefano, Rosanne; Lepine, Sebastien

    2017-01-01

    The region within a kiloparsec of the Sun is a vast and mysterious place filled with uncharted planets, stars and compact objects, whose masses and properties are unknown. The Gaia space mission provides a unique opportunity to study of this region by measuring parallax distances and proper motions to millions of nearby stars, significantly advancing data available from previous astrometric surveys.We are putting this new astrometric information from the first Gaia data release to a novel use, by searching for matches between the positions of known microlensing events and the positions of stars observed by both the Gaia and the Tycho-2 missions, as listed in the Tycho-Gaia Astrometric Solution (TGAS) Catalogue.The existence of a gravitational microlensing event near a TGAS-listed star may provide information about the nature of either the source star lensed in the event, or the lens itself. For example, the source star lensed in the ‘TAGO’ event lies nearby, and is listed in the TGAS Catalogue. Other events may also have been caused by nearby TGAS-listed stars, or by their dim companions. In such cases, we can determine the lens mass and acquire information about any compact objects or planets which may exist around the lens.We report on the process of matching the positions of over 20,000 candidate microlensing events discovered by either OGLE and/or MOA, with the positions of 2 million stars from the TGAS Catalogue and stars from a range of other surveys, including Lepine's SUPERBLINK survey, and discuss the implications of the matches obtained.

  16. Empirical study of simulated two-planet microlensing events

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wei; Gould, Andrew; Penny, Matthew [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Mao, Shude [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Gendron, Rieul, E-mail: weizhu@astronomy.ohio-state.edu [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom)

    2014-10-10

    We undertake the first study of two-planet microlensing models recovered from simulations of microlensing events generated by realistic multiplanet systems in which 292 planetary events, including 16 two-planet events, were detected from 6690 simulated light curves. We find that when two planets are recovered, their parameters are usually close to those of the two planets in the system most responsible for the perturbations. However, in 1 of the 16 examples, the apparent mass of both detected planets was more than doubled by the unmodeled influence of a third, massive planet. This fraction is larger than but statistically consistent with the roughly 1.5% rate of serious mass errors due to unmodeled planetary companions for the 274 cases from the same simulation in which a single planet is recovered. We conjecture that an analogous effect due to unmodeled stellar companions may occur more frequently. For 7 out of 23 cases in which two planets in the system would have been detected separately, only one planet was recovered because the perturbations due to the two planets had similar forms. This is a small fraction (7/274) of all recovered single-planet models, but almost a third of all events that might plausibly have led to two-planet models. Still, in these cases, the recovered planet tends to have parameters similar to one of the two real planets most responsible for the anomaly.

  17. First observation of parallax in a gravitational microlensing event

    CERN Document Server

    Alcock, C B; Alves, D R; Axelrod, T S; Bennett, D P; Cook, K H; Freeman, K C; Griest, K; Guern, J A; Lehner, M J; Marshall, S L; Peterson, B A; Pratt, M R; Quinn, P J; Rodgers, A W; Stubbs, C W; Sutherland, W

    1995-01-01

    We present the first detection of parallax effects in a gravitational microlensing event. Parallax in a gravitational microlensing event observed only from the Earth appears as a distortion of the lightcurve due to the motion of the Earth around the Sun. This distortion can be detected if the event duration is not much less than a year and if the projected velocity of the lens is not much larger than the orbital velocity of the Earth about the Sun. The event presented here has a duration of 220 days and clearly shows the distortion due to the Earth's motion. We find that the projected velocity of the lens is 75+/-5 km/s at an angle of 28+/-4 deg from the direction of increasing galactic longitude, as expected for a lens in the galactic disk. A likelihood analysis yields estimates of the distance to and mass of the lens: D_{lens} = 1.7 (+1.1/-0.7) kpc and M = 1.3 (+1.3/-0.6) Msun, suggesting that the lens is a remnant such as a white dwarf or neutron star. A less likely possibility is that the lens is a main s...

  18. A Candidate M31/M32 Intergalactic Microlensing Event

    CERN Document Server

    Paulin-Henriksson, S; Bouquet, A; Carr, B J; Creze, M; Evans, N W; Giraud-Héraud, Yannick; Gould, A; Hewett, P C; Kaplan, J; Kerins, E; Le Du, Y; Melchior, A L; Smartt, S J; Valls-Gabaud, D

    2002-01-01

    We report the discovery of a microlensing candidate projected 2'54" from the center of M32, on the side closest to M31. The blue color (R-I= 0.00 +/- 0.14) of the source argues strongly that it lies in the disk of M31, while the proximity of the line of sight to M32 implies that this galaxy is the most likely host of the lens. If this interpretation is correct, it would confirm previous arguments that M32 lies in front of M31. We estimate that of order one such event or less should be present in the POINT-AGAPE data base. If more events are discovered in this direction in a dedicated experiment, they could be used to measure the mass function of M32 up to an unknown scale factor. By combining microlensing observations of a binary-lens event with a measurement of the M31-M32 relative proper motion using the astrometric satellites SIM or GAIA, it will be possible to measure the physical separation of M31 and M32, the last of the six phase-space coordinates needed to assign M32 an orbit.

  19. Microlensing by Multiple Planets in High Magnification Events

    CERN Document Server

    Gaudi, B S; Sackett, P D; Sackett, Penny D.

    1998-01-01

    Microlensing is increasingly gaining recognition as a powerful method for the detection and characterization of extra-solar planetary systems. Naively, one might expect that the probability of detecting the influence of more than one planet on any single microlensing light curve would be small. Recently, however, Griest & Safizadeh (1998) have shown that, for a subset of events, those with minimum impact parameter $u_{min} \\lsim 0.1$ (high magnification events), the detection probability is nearly 100% for Jovian mass planets with projected separations in the range 0.6--1.6 of the primary Einstein ring radius $R_E$, and remains substantial outside this zone. In this Letter, we point out that this result implies that, regardless of orientation, all Jovian mass planets with separations near 0.6--1.6$R_E$ dramatically affect the central region of the magnification pattern, and thus have a significant probability of being detected (or ruled out) in high magnification events. The probability, averaged over all...

  20. Detectability of GW150914-like events by gravitational microlensing

    CERN Document Server

    Eilbott, Daniel H; Cohn, Jonathan H; Kesden, Michael; King, Lindsay J

    2016-01-01

    The recent discovery of gravitational waves from stellar-mass binary black holes (BBHs) provided direct evidence of the existence of these systems. These BBHs would have gravitational microlensing signatures that are, due to their large masses and small separations, distinct from single-lens signals. We apply Bayesian statistics to examine the distinguishability of BBH microlensing events from single-lens events under ideal observing conditions, using modern photometric and astrometric capabilities. The parameter space of stellar-mass BBHs is explored to determine what parameter values optimize detectability. Given one year of ideal observations, a source star at the Galactic center, a GW150914-like BBH lens (total mass 65 solar masses, mass ratio 0.8) at half that distance, and an impact parameter of 0.4 Einstein radii, we find that BBH separations down to 0.00682 Einstein radii are detectable. Holding all other parameters constant, impact parameters <= 0.473 Einstein radii result in detectable BBHs with ...

  1. Difference Image Analysis of the OGLE-II bulge data. II. Microlensing events

    CERN Document Server

    Wozniak, P R; Szymanski, M H; Kubiak, M; Pietrzynski, G; Soszynski, I; Zebrun, K

    2001-01-01

    We present a sample of microlensing events discovered in the Difference Image Analysis (DIA) of the OGLE-II images collected during 3 observing seasons, 1997--1999. 4424 light curves pass our criteria on the presence of a brightening episode on top of a constant baseline. Among those, 512 candidate microlensing events were selected visually. We designed an automated procedure, which unambiguously selects up to 237 best events. Including 8 candidate events recovered by other means, a total of 520 light curves are presented in this work. In addition to microlensing events, the larger sample contains certain types of transients, but is also strongly contaminated by artifacts. All 4424 light curves in the weakly filtered group are available electronically, with the intent of showing the gray zone between microlensing events and variable stars, as well as artifacts, to some extent inevitable in massive data reductions. We welcome suggestions for improving the selection process before the full analysis of complete ...

  2. Probing the gravitational Faraday rotation using quasar X-ray microlensing.

    Science.gov (United States)

    Chen, Bin

    2015-11-17

    The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission.

  3. Microlensing by multiple planets in high-magnification events

    NARCIS (Netherlands)

    Gaudi, BS; Sackett, PD

    1998-01-01

    Microlensing is increasingly gaining recognition as a powerful method for the detection and characterization of extrasolar planetary systems. Naively, one might expect that the probability of detecting the influence of more than one planet on any single microlensing light curve would be small. Recen

  4. PLANETARY AND OTHER SHORT BINARY MICROLENSING EVENTS FROM THE MOA SHORT-EVENT ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, D. P. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Bond, I. A.; Ling, C. H. [Institute for Information and Mathematical Sciences, Massey University, Auckland 1330 (New Zealand); Kamiya, K.; Abe, F.; Fukui, A.; Furusawa, K.; Itow, Y.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Botzler, C. S.; Rattenbury, N. J. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Korpela, A. V.; Sullivan, D. J. [School of Chemical and Physical Sciences, Victoria University, Wellington (New Zealand); Kilmartin, P. M. [Mt. John Observatory, P.O. Box 56, Lake Tekapo 8770 (New Zealand); Ohnishi, K. [Nagano National College of Technology, Nagano 381-8550 (Japan); Saito, To., E-mail: bennett@nd.edu [Tokyo Metropolitan College of Aeronautics, Tokyo 116-8523 (Japan); Collaboration: MOA Collaboration; and others

    2012-10-01

    We present the analysis of four candidate short-duration binary microlensing events from the 2006-2007 MOA Project short-event analysis. These events were discovered as a by-product of an analysis designed to find short-timescale single-lens events that may be due to free-floating planets. Three of these events are determined to be microlensing events, while the fourth is most likely caused by stellar variability. For each of the three microlensing events, the signal is almost entirely due to a brief caustic feature with little or no lensing attributable mainly to the lens primary. One of these events, MOA-bin-1, is due to a planet, and it is the first example of a planetary event in which the stellar host is only detected through binary microlensing effects. The mass ratio and separation are q (4.9 {+-} 1.4) Multiplication-Sign 10{sup -3} and s = 2.10 {+-} 0.05, respectively. A Bayesian analysis based on a standard Galactic model indicates that the planet, MOA-bin-1Lb, has a mass of m{sub p} = 3.7 {+-} 2.1 M{sub Jup} and orbits a star of M{sub *} = 0.75{sub -0.41}{sup +}0{sup .33} M{sub Sun} at a semimajor axis of a = 8.3{sub -2.7}{sup +4.5} AU. This is one of the most massive and widest separation planets found by microlensing. The scarcity of such wide-separation planets also has implications for interpretation of the isolated planetary mass objects found by this analysis. If we assume that we have been able to detect wide-separation planets with an efficiency at least as high as that for isolated planets, then we can set limits on the distribution of planets in wide orbits. In particular, if the entire isolated planet sample found by Sumi et al. consists of planets bound in wide orbits around stars, we find that it is likely that the median orbital semimajor axis is >30 AU.

  5. Ultra-high angular resolution by gravitational microlensing

    CERN Document Server

    Bogdanov, M B

    2000-01-01

    The problem of restoration of the source brightness distribution from an analysis of the stellar and AGNs microlensing light curves is investigated. In case of microlensing of stars by a point-mass lens as well as for caustic crossing events for binary lens the problem can be reduced to solution of the Fredholm integral equation of the 1st kind. Concrete form of the kernel of this equation depends on a type of the microlensing event. Assuming the circular symmetry of the stellar disk the search for radial brightness distribution can be carried out in the special compact sets of functions which correspond to the physics of the problem. These sets include the non-negative functions that are not increasing with increasing distance from the center of stellar disk and the upwards convex non-negative functions. The brightness distribution for the AGNs accretion disks is also circularly symmetric, but only in the locally co-moving frame. Therefore, the kernel of integral equation that determined the AGN microlensing...

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

    CERN Document Server

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

    2005-01-01

    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 a...

  7. Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

    Science.gov (United States)

    Zhu, Wei; Gould, Andrew

    2016-06-01

    Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

  8. The advantages of using a Lucky Imaging camera for observations of microlensing events

    CERN Document Server

    Sajadian, Sedighe; Dominik, Martin; Hundertmark, Markus

    2016-01-01

    In this work, we study the advantages of using a Lucky Imaging camera for the observations of potential planetary microlensing events. Our aim is to reduce the blending effect and enhance exoplanet signals in binary lensing systems composed of an exoplanet and the corresponding parent star. We simulate planetary microlensing light curves based on present microlensing surveys and follow-up telescopes where one of them is equipped with a Lucky imaging camera. This camera is used at the Danish $1.54$-m follow-up telescope. Using a specific observational strategy, For an Earth-mass planet in the resonance regime, where the detection probability in crowded-fields is smaller, lucky imaging observations improve the detection efficiency which reaches 2 per cent. Given the difficulty of detecting the signal of an Earth-mass planet in crowded-field imaging even in the resonance regime with conventional cameras, we show that Lucky Imaging can substantially improve the detection efficiency.

  9. The microlensing events in Q2237+0305A no case against small masses\\/large sources

    CERN Document Server

    Haugan, S V H

    1995-01-01

    It is demonstrated that the 1988-90 microlensing events in image A of Q2237+0305 reported by Racine (1992) do not exclude microlensing models with very low average mass, making the source radius larger than the projected Einstein radius \\eta_0 (Refsdal and Stabell 1991 1993). This is contrary to what has been claimed by Witt and Mao (1994). Since these events are the best resolved microlensing events recorded in Q2237+0305, further work should not exclude the possibility of a large source when interpreting lightcurve data.

  10. Study by MOA of extra-solar planets in gravitational microlensing events of high magnification

    OpenAIRE

    Bond, I. A.; Rattenbury, N. J.; Skuljan, J.; Abe, F.; Dodd, R. J.; Hearnshaw, J. B.; Honda, M.; Jugaku, J.; Kilmartin, P. M.; Marles, A.; Masuda, K.; Matsubara, Y.; Muraki, Y.(Solar-Terrestrial Environment Laboratory, Nagoya University, Japan); Nakamura, T.; Nankivell, G.

    2001-01-01

    A search for extra-solar planets was carried out in three gravitational microlensing events of high magnification, MACHO 98-BLG-35, MACHO 99-LMC-2, and OGLE 00-BUL-12. Photometry was derived from observational images by the MOA and OGLE groups using an image subtraction technique. For MACHO 98-BLG-35, additional photometry derived from the MPS and PLANET groups was included. Planetary modeling of the three events was carried out in a super-cluster computing environment. The estimated probabil...

  11. Red Noise Versus Planetary Interpretations in the Microlensing Event Ogle-2013-BLG-446

    Science.gov (United States)

    Bachelet, E.; Bramich, D. M.; Han, C.; Greenhill, J.; Street, R. A.; Gould, A.; D'Ago, G.; AlSubai, K.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Hundertmark, M.; Kains, N.; Snodgrass, C.; Steele, I. A.; Tsapras, Y.; RoboNet Collaboration; Albrow, M. D.; Batista, V.; Beaulieu, J.-P.; Bennett, D. P.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Hill, K.; Marquette, J.-B.; Menzies, J.; Pere, C.; Ranc, C.; Wambsganss, J.; Warren, D.; PLANET Collaboration; de Almeida, L. Andrade; Choi, J.-Y.; DePoy, D. L.; Dong, S.; Hung, L.-W.; Hwang, K.-H.; Jablonski, F.; Jung, Y. K.; Kaspi, S.; Klein, N.; Lee, C.-U.; Maoz, D.; Muñoz, J. A.; Nataf, D.; Park, H.; Pogge, R. W.; Polishook, D.; Shin, I.-G.; Shporer, A.; Yee, J. C.; μFUN Collaboration; Abe, F.; Bhattacharya, A.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Itow, Y.; Koshimoto, N.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Ohnishi, K.; Philpott, L. C.; Rattenbury, N.; Saito, To.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; MOA Collaboration; Bozza, V.; Calchi Novati, S.; Ciceri, S.; Galianni, P.; Gu, S.-H.; Harpsøe, K.; Hinse, T. C.; Jørgensen, U. G.; Juncher, D.; Korhonen, H.; Mancini, L.; Melchiorre, C.; Popovas, A.; Postiglione, A.; Rabus, M.; Rahvar, S.; Schmidt, R. W.; Scarpetta, G.; Skottfelt, J.; Southworth, John; Stabile, An.; Surdej, J.; Wang, X.-B.; Wertz, O.; MiNDSTEp Collaboration

    2015-10-01

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

  12. RED NOISE VERSUS PLANETARY INTERPRETATIONS IN THE MICROLENSING EVENT OGLE-2013-BLG-446

    Energy Technology Data Exchange (ETDEWEB)

    Bachelet, E.; Bramich, D. M.; AlSubai, K. [Qatar Environment and Energy Research Institute, Qatar Foundation, P.O. Box 5825, Doha (Qatar); Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Greenhill, J. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Street, R. A.; Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Gould, A.; Batista, V. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); D’Ago, G. [Dipartimento di Fisica “E.R. Caianiello,” Università di Salerno, Via Ponte Don Melillo, I-84084-Fisciano (Italy); Dominik, M.; Jaimes, R. Figuera; Horne, K.; Hundertmark, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Kains, N. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Snodgrass, C. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37077 Gttingen (Germany); Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool CH41 1LD (United Kingdom); Albrow, M. D. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8020 (New Zealand); Beaulieu, J.-P. [UPMC-CNRS, UMR 7095, Institut dAstrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France); Bennett, D. P., E-mail: c.botzler@auckland.ac.nz, E-mail: p.yock@auckland.ac.nz, E-mail: bennett@nd.edu, E-mail: abe@stelab.nagoya-u.ac.jp, E-mail: furusawa@stelab.nagoya-u.ac.jp, E-mail: itow@stelab.nagoya-u.ac.jp [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Collaboration: RoboNet collaboration; PLANET collaboration; μFUN collaboration; MOA collaboration; MiNDSTEp collaboration; and others

    2015-10-20

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

  13. Microlensing of the Fe K$\\alpha$ line and the X-ray continuum

    CERN Document Server

    Popovic, L C; Mediavilla, E; Zakharov, A F; Abajas, C; Muñoz, J A; Chartas, G

    2005-01-01

    The observed enhancement of the Fe K$\\alpha$ line in three gravitationally lensed QSOs (MG J0414+0534, QSO 2237+0305, H1413+117) is interpreted in terms of microlensing, even when equivalent X-ray continuum amplification is not observed. In order to interpret these observations, first we studied the effects of microlensing on quasars spectra, produced by straight fold caustic crossing over standard relativistic accretion disk. The disk emission was analyzed using the ray tracing method, considering Schwarzschild and Kerr metrics. When the emission is separated in two regions (an inner disk corresponding to the Fe K$\\alpha$ line and an outer annulus corresponding to the continuum, or vice-versa) we find microlensing events which enhance the Fe K$\\alpha$ line without noticeable amplification of the X-ray continuum, but only during a limited time interval. Continuum amplification is expected if a complete microlensing event is monitored. Second, we studied a more realistic case of amplification by caustic magnif...

  14. UKIRT microlensing surveys as a pathfinder for $WFIRST$: The detection of five highly extinguished low-$|b|$ events

    CERN Document Server

    Shvartzvald, Y; Gould, A; Henderson, C B; Howell, S B; Beichman, C

    2016-01-01

    Optical microlensing surveys are restricted from detecting events near the Galactic plane and center, where the event rate is thought to be the highest, due to the high optical extinction of these fields. In the near-infrared (NIR), however, the lower extinction leads to a corresponding increase in event detections and is a primary driver for the wavelength coverage of the $WFIRST$ microlensing survey. During the 2015 and 2016 bulge observing seasons we conducted NIR microlensing surveys with UKIRT in conjunction with and in support of the $Spitzer$ and $Kepler$ microlensing campaigns. Here we report on five highly extinguished ($A_H=0.81-1.97$), low-Galactic latitude ($-0.98\\le b\\le -0.36$) microlensing events discovered from our 2016 survey. Four of them were monitored with an hourly cadence by optical surveys but were not reported as discoveries, likely due to the high extinction. Our UKIRT surveys and suggested future NIR surveys enable the first measurement of the microlensing event rate in the NIR. This...

  15. Spectroscopic characterisation of microlensing events Towards a new interpretation of OGLE-2011-BLG-0417

    CERN Document Server

    Santerne, A; Ayala, B Rojas; Boisse, I; Schlawin, E; Almenara, J -M; Batista, V; Bennett, D; Díaz, R F; Figueira, P; James, D J; Herter, T; Lillo-Box, J; Marquette, J B; Ranc, C; Santos, N C; Sousa, S G

    2016-01-01

    The microlensing event OGLE-2011-BLG-0417 is an exceptionally bright lens binary that was predicted to present radial velocity variation at the level of several km/s. Pioneer radial velocity follow-up observations with the UVES spectrograph at the ESO - VLT of this system clearly ruled out the large radial velocity variation, leaving a discrepancy between the observation and the prediction. In this paper, we further characterise the microlensing system by analysing its spectral energy distribution (SED) derived using the UVES spectrum and new observations with the ARCoIRIS (CTIO) near-infrared spectrograph and the Keck adaptive optics instrument NIRC2 in the J, H, and Ks bands. We determine the mass and distance of the stars independently from the microlensing modelling. We find that the SED is compatible with a giant star in the Galactic bulge and a foreground star with a mass of 0.94+/-0.09Msun at a distance of 1.07+/-0.24kpc. We find that this foreground star is likely the lens. Its parameters are not comp...

  16. "Rare" Microlensing Events: how frequent are they? what can they teach us?

    Science.gov (United States)

    Di Stefano, Rosanne; Bryk, William; Ginsburg, Idan; Greiner, Jochen; Lepine, Sebastien; Oprescu, Antonia; Primini, Francis A.; Tunbridge, Ben

    2014-06-01

    Today's microlensing teams discover roughly 2000 candidate microlensing events per year. Many of these exhibit the standard point-source/point-lens form, and are caused by distant lenses we cannot detect. In our poster we report on the preliminary results of a long term program of analysis designed to identify and study "rare" gravitational lensing events. We have focused on those rare events with light curve profiles that differ from the point-source/point-lens form. These unusual light curves provide additional information about the lens or source. We devote special effort to the study of a small set of events that appear to have been caused by nearby lenses. Nearby lenses are interesting, whatever the form of the light curve they generate. We show that some unusual events are common enough that their systematic study can be scientifically fruitful, allowing lensing programs to identify nearby (closer than a kiloparsec) compact objects and measure their masses, and to also identify and measure masses in nearby planetary systems. We have developed methods that should prove useful in a wide range of ground-based and space-based lensing studies.

  17. Interpretation of a short-term anomaly in the gravitational microlensing event MOA-2012-BLG-486

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, K.-H.; Choi, J.-Y.; Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Bond, I. A. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand); Sumi, T.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Gaudi, B. S.; Gould, A. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bozza, V. [Dipartimento di Fisica " E. R. Caianiello," Università degli Studi di Salerno, Via S. Allende, I-84081 Baronissi (Italy); Beaulieu, J.-P. [UPMC-CNRS, UMR7095, Institut d' Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Goleta, CA 93117 (United States); Abe, F.; Fukunaga, D.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Chote, P.; Harris, P. [School of Chemical and Physical Sciences, Victoria University, Wellington (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Collaboration: MOA Collaboration; μFUN Collaboration; PLANET Collaboration; RoboNet Collaboration; and others

    2013-11-20

    A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present the analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.

  18. Detection Level Enhancement of Gravitational Microlensing Events from the Light Curves

    CERN Document Server

    Ibrahim, Ichsan; Djamal, Mitra; Kunjaya, Chatief; Jaelani, Anton Timur; Putri, Gerhana Puannandra

    2015-01-01

    In Astronomy, intensity of the source light is expressed in magnitude. Conventionally, magnitude is defined by logarithmic function of the received flux. This relationship is known as Pogson formulae. For received flux with small signal to noise ratio (S/N), the formulae gives large magnitude error. We want to inspect whether using Inverse Hyperbolic Sine function (hereinafter referred to as Asinh magnitude) can give an alternative calculation of magnitudes for small S/N flux and gives better results to represent the magnitude for that region. We study the possibility of increasing detection level of gravitational microlensing from 40 selected microlensing events light curves for 2013 and 2014 season by using Asinh magnitude. We obtained that the use of the Asinh make the events brighter than using logarithmic with average of about 3.42 x 10^-2 magnitude. We find also average of magnitude error difference between logarithmic magnitude and Asinh magnitude to is about 2.21 x 10^-2 magnitude, so we propose a lim...

  19. A Giant Planet beyond the Snow Line in Microlensing Event OGLE-2011-BLG-0251

    CERN Document Server

    Kains, N; Choi, J -Y; Han, C; Udalski, A; Almeida, L A; Jablonski, F; Tristram, P; Jorgensen, U G; Szymanski, M K; Kubiak, M; Pietrzynski, G; Soszynski, I; Poleski, R; Kozlowski, S; Pietrukowicz, P; Ulaczyk, K; Wyrzykowski, L; Skowron, J; Alsubai, K A; Bozza, V; Browne, P; Burgdorf, M J; Novati, S Calchi; Dodds, P; Dominik, M; Dreizler, S; Fang, X -S; Grundahl, F; Gu, C -H; Hardis, S; Harpsoe, K; Hessman, F V; Hinse, T C; Hornstrup, A; Hundertmark, M; Jessen-Hansen, J; Kerins, E; Liebig, C; Lund, M; Lundkvist, M; Mancini, L; Mathiasen, M; Penny, M T; Rahvar, S; Ricci, D; Sahu, K C; Scarpetta, G; Skottfelt, J; Snodgrass, C; Southworth, J; Surdej, J; Tregloan-Reed, J; Wambsganss, J; Wertz, O; Bajek, D; Bramich, D M; Horne, K; Ipatov, S; Steele, I A; Tsapras, Y; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Chote, P; Freeman, M; Fukui, A; Furusawa, K; Itow, Y; Ling, C H; Masuda, K; Matsubara, Y; Miyake, N; Muraki, Y; Ohnishi, K; Rattenbury, N; Saito, T; Sullivan, D J; Sumi, T; Suzuki, D; Suzuki, K; Sweatman, W L; Takino, S; Wada, K; Yock, P C M; Allen, W; Batista, V; Chung, S -J; Christie, G; DePoy, D L; Drummond, J; Gaudi, B S; Gould, A; Henderson, C; Jung, Y -K; Koo, J -R; Lee, C -U; McCormick, J; McGregor, D; Munoz, J A; Natusch, T; Ngan, H; Park, H; Pogge, R W; Shin, I -G; Yee, J; Albrow, M D; Bachelet, E; Beaulieu, J -P; Brillant, S; Caldwell, J A R; Cassan, A; Cole, A; Corrales, E; Coutures, Ch; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouque, P; Greenhill, J; Kane, S R; Kubas, D; Marquette, J -B; Martin, R; Meintjes, P; Menzies, J; Pollard, K R; Williams, A; Wouters, D; Zub, M

    2013-01-01

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

  20. First simultaneous microlensing observations by two space telescopes: $Spitzer$ & $Swift$ reveal a brown dwarf in event OGLE-2015-BLG-1319

    CERN Document Server

    Shvartzvald, Y; Udalski, A; Gould, A; Sumi, T; Street, R A; Novati, S Calchi; Hundertmark, M; Bozza, V; Beichman, C; Bryden, G; Carey, S; Drummond, J; Fausnaugh, M; Gaudi, B S; Henderson, C B; Tan, T G; Wibking, B; Pogge, R W; Yee, J C; Zhu, W; Tsapras, Y; Bachelet, E; Dominik, M; Bramich, D M; Cassan, A; Jaimes, R Figuera; Horne, K; Ranc, C; Schmidt, R; Snodgrass, C; Wambsganss, J; Steele, I A; Menzies, J; Mao, S; Poleski, R; Pawlak, M; Szymański, M K; Skowron, J; Mróz, P; Kozłowski, S; Wyrzykowski, Ł; Pietrukowicz, P; Soszyński, I; Ulaczyk, K; Abe, F; Asakura, Y; Barry, R K; Bennett, D P; Bhattacharya, A; Bond, I A; Freeman, M; Hirao, Y; Itow, Y; Koshimoto, N; Li, M C A; Ling, C H; Masuda, K; Fukui, A; Matsubara, Y; Muraki, Y; Nagakane, M; Nishioka, T; Ohnishi, K; Oyokawa, H; Rattenbury, N J; Saito, To; Sharan, A; Sullivan, D J; Suzuki, D; Tristram, P J; Yonehara, A; Jørgensen, U G; Burgdorf, M J; Ciceri, S; D'Ago, G; Evans, D F; Hinse, T C; Kains, N; Kerins, E; Korhonen, H; Mancini, L; Popovas, A; Rabus, M; Rahvar, S; Scarpetta, G; Skottfelt, J; Southworth, J; Peixinho, N; Verma, P; Sbarufatti, B; Kennea, J A; Gehrels, N

    2016-01-01

    Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax". We report the discovery of a 30-55$M_J$ brown dwarf orbiting a K dwarf in microlensing event OGLE-2015-BLG-1319. The system is located at a distance of $\\sim$5 kpc toward the Galactic bulge. The event was observed by several ground-based groups as well as by $Spitzer$ and $Swift$, allowing the measurement of the physical properties. However, the event is still subject to an 8-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either $\\sim$0.25 AU or $\\sim$45 AU. This is the first microlensing event observed by $Swift$, with the UVOT camera. We study the region of microlensing parameter space to which $Swift$ is sensitive, finding that while for thi...

  1. Peculiar Transverse Velocities of Galaxies from Quasar Microlensing. Tentative Estimate of the Peculiar Velocity Dispersion at $z\\sim 0.5$

    CERN Document Server

    Mediavilla, E; Munoz, J A; Battaner, E

    2016-01-01

    We propose to use the flux variability of lensed quasar images induced by gravitational microlensing to measure the transverse peculiar velocity of lens galaxies over a wide range of redshift. Microlensing variability is caused by the motions of the observer, the lens galaxy (including the motion of the stars within the galaxy), and the source; hence, its frequency is directly related to the galaxy's transverse peculiar velocity. The idea is to count time-event rates (e.g., peak or caustic crossing rates) in the observed microlensing light curves of lensed quasars that can be compared with model predictions for different values of the transverse peculiar velocity. To compensate for the large time-scale of microlensing variability we propose to count and model the number of events in an ensemble of gravitational lenses. We develop the methodology to achieve this goal and apply it to an ensemble of 17 lensed quasar systems. In spite of the shortcomings of the available data, we have obtained tentative estimates...

  2. Constraints on Jupiters from observations of Galactic Bulge microlensing events during 2000

    CERN Document Server

    Tsapras, Y; Carson, R S; Alvarez-Mendez, J; Batcheldor, D; Graham, A W; James, P A; Knapen, J H; Quaintrell, H; González-Serrano, J I; Sørensen, P; Wooder, N; Tsapras, Yiannis; Horne, Keith; Carson, Richard; Alvarez, Javier Mendez; Batcheldor, Dan; Graham, Alister W.; James, Philip A.; Knapen, Johan; Quaintrell, Hannah; Serrano, Ignacio Gonzalez; Sorensen, Peter; Wooder, Nick

    2002-01-01

    We present observations of 8 Galactic Bulge microlensing events taken with the 1.0m JKT on La Palma during 2000 June and July. The JKT observing schedule was optimized using a prioritizing algorithm to automatically update the target list. For most of these events we have sampled the lightcurves at times where no information was available from the OGLE alert team. We assume a point-source point-lens (PSPL) model and perform a maximum likelihood fit to both our data and the OGLE data to constrain the event parameters of the fit. We then refit the data assuming a binary lens and proceed to calculate the probability of detecting planets with mass ratio $q=10^{-3}$. We have seen no clear signatures of planetary deviations on any of the 8 events and we quantify constraints on the presence of planetary companions to the lensing stars. For two well observed events, 2000BUL31 and 2000BUL33, our detection probabilities peak at $\\sim$30% and $\\sim$20% respectively for $q=10^{-3}$ and $a \\sim R_{E}$ for a $\\Delta\\chi^2$...

  3. Properties of microlensing events by wide separation planets with a moon

    CERN Document Server

    Chung, Sun-Ju

    2016-01-01

    We investigate the properties of microlensing events caused by planetary systems where planets with a moon are widely separated from their host stars. From this investigation, we find that the moon feature generally appears as an very short-duration perturbation on the smooth asymmetric light curve of the lensing event induced by the wide separation planet; thus it can be easily discriminated from the planet feature responsible for the overall asymmetric light curve. For typical Galactic lensing events with the Einstein radius of $\\sim 2$ AU, the asymmetry of the light curves due to bound planets can be noticed up to $\\sim 20$AU. We also find that the perturbations of the wide planetary systems become dominated by the moon as the projected star-planet separation increases, and eventually the light curves of events produced by the systems appear as the single lensing light curve of the planet itself with a very short-duration perturbation induced by the moon, which is a representative light curve of the event ...

  4. Studying the microlenses mass function from statistical analysis of the caustic concentration

    Energy Technology Data Exchange (ETDEWEB)

    Mediavilla, T; Ariza, O [Departamento de Estadistica e Investigacion Operativa, Universidad de Cadiz, Avda de Ramon Puyol, s/n 11202 Algeciras (Spain); Mediavilla, E [Instituto de Astrofisica de Canarias, Avda Via Lactea s/n, La Laguna (Spain); Munoz, J A, E-mail: teresa.mediavilla@ca.uca.es, E-mail: octavio.ariza@uca.es, E-mail: emg@iac.es [Departamento de Astrofisica y Astronomia, Universidad de Valencia, Burjassot, Valencia (Spain)

    2011-09-22

    The statistical distribution of caustic crossings by the images of a lensed quasar depends on the properties of the distribution of microlenses in the lens galaxy. We use a procedure based in Inverse Polygon Mapping to easily identify the critical and caustic curves generated by a distribution of stars in the lens galaxy. We analyze the statistical distributions of the number of caustic crossings by a pixel size source for several projected mass densities and different mass distributions. We compare the results of simulations with theoretical binomial distributions. Finally we apply this method to the study of the stellar mass distribution in the lens galaxy of QSO 2237+0305.

  5. A New Non-Planetary Interpretation of the Microlensing Event OGLE-2013-BLG-0723

    CERN Document Server

    Han, Cheongho; Udalski, Andrzej; Jung, Youn Kil

    2016-01-01

    Recently, the discovery of a Venus-mass planet orbiting a brown-dwarf host in a binary system was reported from the analysis of the microlensing event OGLE-2013-BLG-0723. We reanalyze the event considering the possibility of other interpretations. From this, we find a new solution where the lens is composed of 2 bodies in contrast to the 3-body solution of the previous analysis. The new solution better explains the observed light curve than the previous solution with $\\Delta\\chi^2\\sim 202$, suggesting that the new solution is a correct model for the event. From the estimation of the physical parameters based on the new interpretation, we find that the lens system is composed of two low-mass stars with $\\sim 0.2\\ M_\\odot$ and $\\sim 0.1\\ M_\\odot$ and located at a distance $\\sim 3$ kpc. The fact that the physical parameters correspond to those of the most common lens population located at a distance with a large lensing probability further supports the likelihood of the new interpretation. Considering that two d...

  6. Properties of Microlensing Events by Wide-separation Planets with a Moon

    Science.gov (United States)

    Chung, Sun-Ju; Ryu, Yoon-Hyun

    2016-07-01

    We investigate the properties of microlensing events caused by planetary systems where planets with a moon are widely separated from their host stars. From this investigation, we find that the moon feature generally appears as a very short-duration perturbation on the smooth asymmetric light curve of the lensing event induced by the wide-separation planet; thus it can be easily discriminated from the planet feature responsible for the overall asymmetric light curve. For typical Galactic lensing events with an Einstein radius of ˜2 au, the asymmetry of the light curves due to bound planets can be noticed up to ˜20 au. We also find that the perturbations of wide planetary systems become dominated by the moon as the projected star-planet separation increases, and eventually the light curves of events produced by such systems appear as the single lensing light curve of the planet itself with a very short-duration perturbation induced by the moon, which is a representative light curve of the event induced by a star and a planet, except on the Einstein timescale of the planet. We also study the effect of a finite source star on the moon feature in wide planetary lensing events. From this study, we find that when the lunar caustic is sufficiently separated from the planetary caustic, the lower limit on the ratio of the size of the lunar caustic to the source radius causing a ≥5% lunar deviation depends mostly on the projected planet-moon separation regardless of the moon/star mass ratio, and it decreases as the planet-moon separation becomes smaller or larger than the planetary Einstein radius.

  7. Discovery of a Gas giant Planet in Microlensing Event OGLE-2014-BLG-1760

    CERN Document Server

    Bhattacharya, A; Bond, I A; Sumi, T; Udalski, A; Street, R; Tsapras, Y; Abe, F; Freeman, M; Fukui, A; Itow, Y; Li, M C A; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Ohnishi, K; Philpott, L C; Rattenbury, N; Saito, T; Sharan, A; Sullivan, D J; Suzuki, D; Tristram, P J; Szymański, M K; Kubiac, M; Pietrzyński, G; Soszyński, I; Poleski, R; Kozlowski, S; Pietrukowicz, P; Ulaczyk, K; Wyrzykowski, L; Bachelet, E; Bramich, D M; Browne, P; Dominik, M; Horne, K; Hundertmark, M; Ipatov, S; Kains, N; Snodgrass, C; Steele, I A

    2016-01-01

    We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong light curve signal due to the presence of a Jupiter mass-ratio planet. One unusual feature of this event is that the source star is quite blue, with $V-I = 1.48\\pm 0.08$. This is marginally consistent with source star in the Galactic bulge, but it could possibly indicate a young source star in the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at $D_L = 6.9 \\pm 1.1 $ kpc. It also indicates a host star mass of $M_* = 0.51 \\pm 0.44 M_\\odot$, a planet mass of $m_p = 180 \\pm 110 M_\\oplus$, and a projected star-planet separation of $a_\\perp = 1.7\\pm 0.3\\,$AU. The lens-source relative proper motion is $\\mu_{\\rm rel} = 6.5\\pm 1.1$ mas/yr. The lens (and stellar host star) is predicted to be very faint, so it is most likely that it can detected only when the lens and sour...

  8. Statistical searches for microlensing events in large, non-uniformly sampled time-domain surveys: A test using palomar transient factory data

    Energy Technology Data Exchange (ETDEWEB)

    Price-Whelan, Adrian M.; Agüeros, Marcel A. [Department of Astronomy, Columbia University, 550 W 120th Street, New York, NY 10027 (United States); Fournier, Amanda P. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States); Street, Rachel [Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Covey, Kevin R. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Levitan, David; Sesar, Branimir [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Laher, Russ R.; Surace, Jason, E-mail: adrn@astro.columbia.edu [Spitzer Science Center, California Institute of Technology, Mail Stop 314-6, Pasadena, CA 91125 (United States)

    2014-01-20

    Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its ∼20,000 deg{sup 2} footprint. While the median 7.26 deg{sup 2} PTF field has been imaged ∼40 times in the R band, ∼2300 deg{sup 2} have been observed >100 times. We use PTF data to study the trade off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >10 R-band observations, 1.1 × 10{sup 9} light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.

  9. Estimating Finite Source Effects in Microlensing Events due to Free-Floating Planets with the Euclid Survey

    Directory of Open Access Journals (Sweden)

    Lindita Hamolli

    2015-01-01

    Full Text Available In recent years free-floating planets (FFPs have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution. The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge. Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs. We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6]. For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters. These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bulge stars.

  10. Estimating Finite Source Effects in Microlensing Events due to Free-Floating Planets with the Euclid Survey

    CERN Document Server

    Hamolli, Lindita; De Paolis, Francesco; Nucita, Achille A

    2015-01-01

    In recent years free-loating planets (FFPs) have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution. The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge. Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs. We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6]. For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters. These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bul...

  11. Discovery of a Gas Giant Planet in Microlensing Event OGLE-2014-BLG-1760

    Science.gov (United States)

    Bhattacharya, A.; Bennett, D. P.; Bond, I. A.; Sumi, T.; Udalski, A.; Street, R.; Tsapras, Y.; Abe, F.; 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.; Rattenbury, N.; Saito, T.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; MOA Collaboration; Skowron, J.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Mróz, P.; Kozlowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Wyrzykowski, L.; OGLE Collaboration; Bachelet, E.; Bramich, D. M.; D'Ago, G.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Hundertmark, M.; Kains, N.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; ROBONET Collaboration

    2016-11-01

    We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong light-curve signal due to the presence of a Jupiter mass ratio planet. One unusual feature of this event is that the source star is quite blue, with V-I=1.48+/- 0.08. This is marginally consistent with a source star in the Galactic bulge, but it could possibly indicate a young source star on the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at {D}L=6.9+/- 1.1 {kpc}. It also indicates a host-star mass of {M}* ={0.51}-0.28+0.44{M}⊙ , a planet mass of {m}{{p}}={0.56}-0.26+0.34{M}J, and a projected star-planet separation of {a}\\perp ={1.75}-0.33+0.34 au. The lens-source relative proper motion is {μ }{rel}=6.5+/- 1.1 mas yr-1. The lens (and stellar host star) is estimated to be very faint compared to the source star, so it is most likely that it can be detected only when the lens and source stars start to separate. Due to the relatively high relative proper motion, the lens and source will be resolved to about ˜46 mas in 6-8 yr after the peak magnification. So, by 2020-2022, we can hope to detect the lens star with deep, high-resolution images.

  12. A new type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-magnification Gravitational Microlensing Events

    DEFF Research Database (Denmark)

    Choi, J.-Y; Shin, I.-G; Han, C.

    2012-01-01

    High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally di...

  13. A New Microlensing Event in the Doubly-Imaged Quasar Q0957+561

    CERN Document Server

    Hainline, Laura J; Beach, J N; Kochanek, C S; Harris, Hugh C; Tilleman, T; Fadely, Ross; Falco, Emilio E; Le, T X

    2011-01-01

    We present evidence for ultraviolet/optical microlensing in the gravitationally lensed quasar Q0957+561. We combine new measurements from our optical monitoring campaign at the United States Naval Observatory, Flagstaff (USNO) with measurements from the literature and find that the time-delay-corrected r-band flux ratio m_A - m_B has increased by ~0.1 magnitudes over a period of five years beginning in the fall of 2005. We apply our Monte Carlo microlensing analysis procedure to the composite light curves, obtaining a measurement of the optical accretion disk size, log {(r_s/cm)[cos(i)/0.5]^{1/2}} = 16.1^{+0.5}_{-0.6}, that is consistent with the quasar accretion disk size - black hole mass relation.

  14. Optical Gravitational Lensing Experiment. OGLE-1999-BUL-32 the Longest Ever Microlensing Event -- Evidence for a Stellar Mass Black Hole?

    CERN Document Server

    Mao, S; Wozniak, P R; Udalski, A; Kubiak, M; Pietrzynski, G; Soszynski, I; Zebrun, K; Mao, Shude; Smith, Martin C.

    2002-01-01

    We describe the discovery of the longest microlensing event ever observed, OGLE-1999-BUL-32, also independently identified by the MACHO collaboration as MACHO-99-BLG-22. This unique event has an Einstein radius crossing time of 641 days. The high quality data obtained with difference image analysis shows a small but significant parallax signature. This parallax effect allows one to determine the Einstein radius projected onto the observer plane as rE^hat ~ 29.2AU. The transverse velocity projected onto the observer plane is about 79km/s. We argue that the lens is likely to be have a mass of at least a few solar masses, i.e., it could be a stellar black hole. The black hole hypothesis can be tested using the astrometric microlensing signature with the soon-to-be installed Advanced Camera for Surveys on board the Hubble Space Telescope. Deep X-ray and radio images may also be useful for revealing the nature of the object.

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

    DEFF Research Database (Denmark)

    Choi, J.-Y.; Shin, I.-G.; Park, S.-Y.

    2012-01-01

    We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-...

  16. Statistical Searches for Microlensing Events in Large, Non-Uniformly Sampled Time-Domain Surveys: A Test Using Palomar Transient Factory Data

    CERN Document Server

    Agüeros, Adrian M Price-Whelan Marcel A; Street, Rachel; Ofek, Eran O; Covey, Kevin R; Levitan, David; Laher, Russ R; Sesar, Branimir; Surace, Jason

    2013-01-01

    Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its $\\sim$$20,000 \\mathrm{deg}^2$ footprint. While the median $7.26 \\mathrm{deg}^2$ PTF field has been imaged $\\sim$40 times in \\textit{R}-band, $\\sim$$2300 \\mathrm{deg}^2$ have been observed $>$100 times. We use PTF data to study the trade-off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a ...

  17. Polarimetric microlensing of circumstellar disks

    CERN Document Server

    Sajadian, Sedighe

    2015-01-01

    We study the benefits of polarimetry observations of microlensing events to detect and characterize circumstellar disks around the microlensed stars located at the Galactic bulge. These disks which are unresolvable from their host stars make a net polarization effect due to their projected elliptical shapes. Gravitational microlensing can magnify these signals and make them be resolved. The main aim of this work is to determine what extra information about these disks can be extracted from polarimetry observations of microlensing events in addition to those given by photometry ones. Hot disks which are closer to their host stars are more likely to be detected by microlensing, owing to more contributions in the total flux. By considering this kind of disks, we show that although the polarimetric efficiency for detecting disks is similar to the photometric observation, but polarimetry observations can help to constraint the disk geometrical parameters e.g. the disk inner radius and the lens trajectory with resp...

  18. The Origin of the Microlensing Events Observed Towards the LMC and the Stellar Counterpart of the Magellanic Stream

    CERN Document Server

    Besla, Gurtina; Loeb, Abraham

    2012-01-01

    We introduce a novel theory to explain the long-standing puzzle of the nature of the microlensing events reported towards the Large Magellanic Cloud (LMC) by the MACHO and OGLE collaborations. We propose that a population of tidally stripped stars from the Small Magellanic Clouds (SMC) located ~4-10 kpc behind a lensing population of LMC disk stars can naturally explain the observed event durations, event frequency and spatial distribution of the reported events. These results favor a scenario for the interaction history of the Magellanic Clouds wherein the Clouds are on their first infall towards the Milky Way and the SMC has recently collided with the LMC, leading to a large number of faint sources distributed non-uniformly behind the LMC disk. Owing to the tidal nature of the source population, the sources exhibit a range of distances and velocities with respect to the LMC lenses, naturally explaining the observed range of event durations (30-220 days). Assuming a detection efficiency of 30-50% we find eve...

  19. Astrophysical Applications of Gravitational Microlensing

    CERN Document Server

    Mao, Shude

    2012-01-01

    Since the first discovery of microlensing events nearly two decades ago, gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications. The review starts with a theoretical overview of the field and then proceeds to discuss the scientific highlights. (1) Microlensing observations toward the Magellanic Clouds rule out the Milky Way halo being dominated by MAssive Compact Halo Objects (MACHOs). This confirms most dark matter is non-baryonic, consistent with other observations. (2) Microlensing has discovered about 20 extrasolar planets (16 published), including the first two Jupiter-Saturn like systems and the only "cold Neptunes" yet detected. They probe a different part of the parameter space and will likely provide the most stringent test of core accretion theory of planet formation. (3) Microlensing provides a unique way to measure the mass of isolated stars, including brown dwarfs to normal stars. Half a dozen or so stellar...

  20. A super-jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406

    Energy Technology Data Exchange (ETDEWEB)

    Tsapras, Y.; Street, R. A. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Choi, J.-Y.; Han, C. [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Bozza, V. [Dipartimento di Fisica " E. R. Caianiello," Università di Salerno, Via Giovanni Paolo II n. 132, I-84084 Fisciano (Italy); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dominik, M.; Browne, P.; Horne, K.; Hundertmark, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Beaulieu, J.-P. [UPMC-CNRS, UMR7095, Institut d' Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Jørgensen, U. G. [Niels Bohr Institute, Astronomical Observatory, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Bramich, D. M.; Kains, N. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Ipatov, S.; Alsubai, K. A. [Qatar Foundation, P.O. Box 5825, Doha (Qatar); Snodgrass, C. [Max Planck Institute for Solar System Research, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool CH41 1LD (United Kingdom); Collaboration: RoboNet Collaboration; MiNDSTEp Collaboration; OGLE Collaboration; PLANET Collaboration; μFUN Collaboration; MOA Collaboration; and others

    2014-02-10

    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 ± 0.43 M {sub J} planet orbiting a 0.44 ± 0.07 M {sub ☉} early M-type star. The distance to the lens is 4.97 ± 0.29 kpc and the projected separation between the host star and its planet at the time of the event is 3.45 ± 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.

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

    CERN Document Server

    Tsapras, Y; Street, R A; Han, C; Bozza, V; Gould, A; Dominik, M; Beaulieu, J -P; Udalski, A; Jørgensen, U G; Sumi, T; Bramich, D M; Browne, P; Horne, K; Hundertmark, M; Ipatov, S; Kains, N; Snodgrass, C; Steele, I A; Alsubai, K A; Andersen, J M; Novati, S Calchi; Damerdji, Y; Diehl, C; Elyiv, A; Giannini, E; Hardis, S; Harpsøe, K; Hinse, T C; Juncher, D; Kerins, E; Korhonen, H; Liebig, C; Mancini, L; Mathiasen, M; Penny, M T; Rabus, M; Rahvar, S; Scarpetta, G; Skottfelt, J; Southworth, J; Surdej, J; Tregloan-Reed, J; Vilela, C; Kozłowski, J Wambsganss S; Kubiak, M; Pietrukowicz, P; Pietrzyński, G; Poleski, R; Skowron, J; Soszyński, I; Szymański, M K; Ulaczyk, K; Albrow, Łukasz Wyrzykowski 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; Fouqué, P; Greenhill, J; Kane, S R; Kubas, D; Marquette, J -B; Martin, R; Menzies, J; Pollard, K R; Williams, A; Wouters, D; Christie, G; DePoy, D L; Dong, S; Drummond, J; Gaudi, B S; Henderson, C B; Hwang, K H; Jung, Y K; Kavka, A; Koo, J -R; Lee, C -U; Maoz, D; Monard, L A G; Natusch, T; Ngan, H; Park, H; Pogge, R W; Porritt, I; Shin, I -G; Shvartzvald, Y; Tan, T G; Yee, J C; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Koshimoto, N; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Sweatman, W L; Suzuki, D; Tristram, P J; Tsurumi, N; Wada, K; Yamai, N; Yonehara, P C M Yock A

    2013-01-01

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

  2. Microlensing Parallax for Observers in Heliocentric Motion

    CERN Document Server

    Novati, S Calchi

    2016-01-01

    Motivated by the ongoing Spitzer observational campaign, and the forecoming K2 one, we revisit, working in an heliocentric reference frame, the geometrical foundation for the analysis of the microlensing parallax, as measured with the simultaneous observation of the same microlensing event from two observers with relative distance of order AU. For the case of observers at rest we discuss the well known fourfold microlensing parallax degeneracy and determine an equation for the degenerate directions of the lens trajectory. For the case of observers in motion, we write down an extension of the Gould (1994) relationship between the microlensing parallax and the observable quantities and, at the same time, we highlight the functional dependence of these same quantities from the timescale of the underlying microlensing event. Furthermore, through a series of examples, we show the importance of taking into account the motion of the observers to correctly recover the parameters of the underlying microlensing event. ...

  3. Revisiting the microlensing event OGLE 2012-BLG-0026: A solar mass star with two cold giant planets

    CERN Document Server

    Beaulieu, J P; Batista, V; Fukui, A; Marquette, J -B; Brillant, S; Cole, A A; Rogers, L A; Sumi, T; Abe, F; Bhattacharya, A; Koshimoto, N; Suzuki, D; Tristram, P J; Han, C; Gould, A; Pogge, R; Yee, J

    2016-01-01

    Two cold, gas giant planets orbiting a G-type main sequence star in the galactic disk have previously been discovered in the high magnification microlensing event OGLE-2012-BLG-0026 (Han et al. 2013). Here we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, $H=16.39 \\pm 0.08$. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B\\&C telescope in New Zealand and CTIO 1.3m H band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of a $\\sim 4-9$ Gyr lens star of $\\rm M_{lens} = 1.06 \\pm 0.05~\\,M_\\odot$ at a distance of $\\rm D_{lens} = 4.0 \\pm 0.3~$kpc, orbited by two giant plan...

  4. OGLE-2016-BLG-0596Lb: High-Mass Planet From High-Magnification Pure-Survey Microlensing Event

    CERN Document Server

    Mróz, P; Udalski, A; Poleski, R; Skowron, J; Szymański, M K; Soszyński, I; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Wyrzykowski, Ł; Pawlak, M; Albrow, M D; Cha, S -M; Chung, S -J; Jung, Y K; Kim, D -J; Kim, S -L; Lee, C -U; Lee, Y; Park, B -G; Pogge, R W; Ryu, Y -H; Shin, I -G; Yee, J C; Zhu, W; Gould, A

    2016-01-01

    We report the discovery of a high mass-ratio planet $q=0.012$, i.e., 13 times higher than the Jupiter/Sun ratio. The host mass is not presently measured but can be determined or strongly constrained from adaptive optics imaging. The planet was discovered in a small archival study of high-magnification events in pure-survey microlensing data, which was unbiased by the presence of anomalies. The fact that it was previously unnoticed may indicate that more such planets lie in archival data and could be discovered by similar systematic study. In order to understand the transition from predominantly survey+followup to predominately survey-only planet detections, we conduct the first analysis of these detections in the observational $(s,q)$ plane. Here $s$ is projected separation in units of the Einstein radius. We find some evidence that survey+followup is relatively more sensitive to planets near the Einstein ring, but that there is no statistical difference in sensitivity by mass ratio.

  5. A possible binary system of a stellar remnant in the high magnification gravitational microlensing event OGLE-2007-BLG-514

    CERN Document Server

    Miyake, N; Sumi, T; Bennett, D P; Dong, S; Street, R A; Greenhill, J; Bond, I A; Gould, A; Kubiak, M; Szymanski, M K; Pietrzynski, G; Soszynski, I; Ulaczyk, K; Wyrzykowski, L; Abe, F; Fukui, A; Furusawa, K; Holderness, S; Itow, Y; Korpela, A; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Nagayama, T; Ohnishi, K; Rattenbury, N; Saito, To; Sako, T; Sullivan, D J; Sweatman, W L; Tristram, P J; Yock, P C M; Allen, W; Christie, G W; DePoy, D L; Gaudi, B S; Han, C; Lee, C -U; McCormick, J; Monard, B; Natusch, T; Park, B -G; Pogge, R W; Allan, A; Bode, M; Bramich, D M; Clay, N; Dominik, M; Horne, K D; Kains, N; Mottram, C; Snodgrass, C; Steele, I; Tsapras, Y; Albrow, M D; Batista, V; Beaulieu, J P; Brillant, S; Burgdorf, M; Caldwell, J A R; Cassan, A; Cole, A; Cook, K H; Coutures, Ch; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouque, P; Jorgensen, U G; Kane, S; Kubas, D; Marquette, J B; Martin, R; Menzies, J; Pollard, K R; Sahu, K C; Wambsganss, J; Williams, A; Zub, M

    2012-01-01

    We report the extremely high magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 +/- 0.007 and a projected separation of s = 0.072 +/- 0.001$ in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D_L = 3.11 +/- 0.39 kpc and total mass M_L=1.40 +/- 0.18 M_sun; this leads to the primary and secondary components having masses of M_1 = 1.06 +/- 0.13 M_sun and M_2 = 0.34 +/- 0.04 M_sun, respectively. The parallax model indicates that the binary lens system is likely constructed by the main sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbi...

  6. Real-time detection of gravitational microlensing

    CERN Document Server

    Pratt, M R; Axelrod, T S; Becker, A; Bennett, D P; Cook, K H; Freeman, K C; Griest, K; Guern, J A; Lehner, M; Marshall, S L; Peterson, B A; Quinn, P J; Reiss, D; Rodgers, A W; Stubbs, C W; Sutherland, W; Welch, D

    1995-01-01

    Real-time detection of microlensing has moved from proof of concept in 1994 to a steady stream of events this year. Global dissemination of these events by the MACHO and OGLE collaborations has made possible intensive photometric and spectroscopic followup from widely dispersed sites confirming the microlensing hypothesis. Improved photometry and increased temporal resolution from followup observations greatly increases the possibility of detecting deviations from the standard point-source, point-lens, inertial motion microlensing model. These deviations are crucial in understanding individual lensing systems by breaking the degeneracy between lens mass, position and velocity. We report here on GMAN (Global Microlensing Alert Network), the coordinated followup of MACHO alerts.

  7. Revisiting the Microlensing Event OGLE 2012-BLG-0026: A Solar Mass Star with Two Cold Giant Planets

    Science.gov (United States)

    Beaulieu, J.-P.; Bennett, D. P.; Batista, V.; Fukui, A.; Marquette, J.-B.; Brillant, S.; Cole, A. A.; Rogers, L. A.; Sumi, T.; Abe, F.

    2016-01-01

    Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 +/- 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B and C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of an approximately 4-9 Gyr lens star of M(sub lens) = 1.06 +/- 0.05 solar mass at a distance of D(sub lens) = 4.0 +/- 0.3 kpc, orbited by two giant planets of 0.145 +/- 0.008 M(sub Jup) and 0.86 +/- 0.06 M(sub Jup), with projected separations of 4.0 +/- 0.5 au and 4.8 +/- 0.7 au, respectively. Because the lens is brighter than the source star by 16 +/- 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.

  8. First microlensing candidates from the MEGA survey of M 31

    NARCIS (Netherlands)

    de Jong, JTA; Kuijken, K; Crotts, APS; Sackett, PD; Sutherland, WJ; Uglesich, RR; Baltz, EA; Cseresnjes, P; Gyuk, G; Widrow, LM

    2004-01-01

    We present the first M 31 candidate microlensing events from the Microlensing Exploration of the Galaxy and Andromeda (MEGA) survey. MEGA uses several telescopes to detect microlensing towards the nearby Andromeda galaxy, M 3 1, in order to establish whether massive compact objects are a significant

  9. New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262

    Energy Technology Data Exchange (ETDEWEB)

    Skowron, Jan [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Udalski, Andrzej; Szymański, Michał K., E-mail: jskowron@astrouw.edu.pl, E-mail: udalski@astrouw.edu.pl, E-mail: msz@astrouw.edu.plm [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); and others

    2014-04-20

    We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t {sub E} = 3.8 day, a companion mass ratio q = 4.7 × 10{sup –3}, and a very high or high lens-source relative proper motion μ{sub rel} = 20 mas yr{sup –1} or 12 mas yr{sup –1} (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass 'moon'. The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment, we measure the source proper motion that is small, μ{sub s}=(−2.3,−0.9)±(2.8,2.6) mas yr{sup −1} in a (north, east) Galactic coordinate frame. These values are then important input into a Bayesian analysis of the event presented in a companion paper by Bennett et al.

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

    CERN Document Server

    Gould, A; Gaudi, B S; Udalski, A; Bond, I A; Greenhill, J; Street, R A; Dominik, M; Sumi, T; Szymanski, M K; Han, C

    2014-01-01

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

  11. New Method to Measure Proper Motions of Microlensed Sources: Application to Candidate Free-Floating-Planet Event MOA-2011-BLG-262

    CERN Document Server

    Skowron, Jan; Szymański, Michał K; Kubiak, Marcin; Pietrzyński, Grzegorz; Soszyński, Igor; Poleski, Radosław; Ulaczyk, Krzysztof; Pietrukowicz, Paweł; Kozłowski, Szymon; Wyrzykowski, Łukasz; Gould, Andrew

    2013-01-01

    We develop a new method to measure source proper motions in microlensing events, which can partially overcome problems due to blending. It takes advantage of the fact that the source position is known precisely from the microlensing event itself. We apply this method to the event MOA-2011-BLG-262, which has a short timescale t_E=3.8 day, a companion mass ratio q=0.0047 and a very high or high lens-source relative proper motion mu_rel=20 mas/yr or 12 mas/yr (for two possible models). These three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass "moon". The probability of such an interpretation would be greatly increased if it could be shown that the high lens-source relative proper motion was primarily due to the lens rather than the source. Based on the long-term monitoring data of the Galactic bulge from the Optical Gravitational Lensing Experiment (OGLE), we measure the source proper motion that is small, mu_s = (-2.3, -0.9) +- (2.8,2.6) mas/yr in a (No...

  12. A POSSIBLE BINARY SYSTEM OF A STELLAR REMNANT IN THE HIGH-MAGNIFICATION GRAVITATIONAL MICROLENSING EVENT OGLE-2007-BLG-514

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, N.; Abe, F.; Furusawa, K.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Udalski, A.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Ulaczyk, K.; Wyrzykowski, L. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Dong, S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Street, R. A. [Las Cumbres Observatory, 6740B Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Greenhill, J. [School of Maths and Physics, University of Tasmania, Private bag 37, GPO Hobart, Tasmania 7001 (Australia); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Okayama 719-0232 (Japan); Holderness, S., E-mail: nmiyake@stelab.nagoya-u.ac.jp [Computer Science Department, University of Auckland, Auckland (New Zealand); Collaboration: OGLE Collaboration; MOA Collaboration; muFUN Collaboration; RoboNet Collaboration; PLANET Collaboration; and others

    2012-06-20

    We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 {+-} 0.007 and a projected separation of s = 0.072 {+-} 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D{sub L} = 3.11 {+-} 0.39 kpc and total mass M{sub L} = 1.40 {+-} 0.18 M{sub Sun }; this leads to the primary and secondary components having masses of M{sub 1} = 1.06 {+-} 0.13 M{sub Sun} and M{sub 2} = 0.34 {+-} 0.04 M{sub Sun }, respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 {+-} 0.005, s = 0.083 {+-} 0.001). The primary component of the binary lens is relatively massive, with M{sub 1} = 0.9{sup +4.6}{sub -0.3} M{sub Sun} and it is at a distance of D{sub L} = 2.6{sup +3.8}{sub -0.9} kpc. Given the secure mass ratio measurement, the companion mass is therefore M{sub 2} = 0.2{sup +1.2}{sub -0.1} M{sub Sun }. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.

  13. A NEw Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-Magnification Gravitational Microlensing Events

    CERN Document Server

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

    2012-01-01

    High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the basically different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for 2 high-magnification events of O...

  14. Astrophysical applications of gravitational microlensing

    Institute of Scientific and Technical Information of China (English)

    Shude Mao

    2012-01-01

    Since the first discovery of microlensing events nearly two decades ago,gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications.The review starts with a theoretical overview of the field and then proceeds to discuss the scientific highlights.(1) Microlensing observations toward the Magellanic Clouds rule out the Milky Way halo being dominated by MAssive Compact Halo Objects (MACHOs).This confirms most dark matter is non-baryonic,consistent with other observations.(2) Microlensing has discovered about 20 extrasolar planets (16 published),including the first two Jupiter-Saturn like systems and the only five "cold Neptunes" yet detected.They probe a different part of the parameter space and will likely provide the most stringent test of core accretion theory of planet formation.(3) Microlensing provides a unique way to measure the mass of isolated stars,including brown dwarfs and normal stars.Half a dozen or so stellar mass black hole candidates have also been proposed.(4) High-resolution,target-of-opportunity spectra of highly-magnified dwarf stars provide intriguing "age" determinations which may either hint at enhanced helium enrichment or unusual bulge formation theories.(5) Microlensing also measured limb-darkening profiles for close to ten giant stars,which challenges stellar atmosphere models.(6) Data from surveys also provide strong constraints on the geometry and kinematics of the Milky Way bar (through proper motions); the latter indicates predictions from current models appear to be too anisotropic compared with observations.The future of microlensing is bright given the new capabilities of current surveys and forthcoming new telescope networks from the ground and from space.Some open issues in the field are identified and briefly discussed.

  15. A new type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-magnification Gravitational Microlensing Events

    DEFF Research Database (Denmark)

    Choi, J.-Y; Shin, I.-G; Han, C.;

    2012-01-01

    High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally...... distinguished due to the essentially different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt...... and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region...

  16. The Next Generation Microlensing Search: SuperMacho

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A; Cook, K; Hiriart, R; Keller, S; Miknaitis, G; Nilolaev, S; Olsen, K; Prochter, G; Rest, A; Schmidt, B; Smith, C; Stubbs, C; Suntzeff, N; Welch, D; Becker, A; Clocchiati, A; Covarrubias, R

    2003-10-27

    Past microlensing experiments such as the MACHO project have discovered the presence of a larger than expected number of microlensing events toward the Large Magellanic Cloud (LMC). These events could represent a large fraction of the dark matter in the halo of our Galaxy, if they are indeed due to halo lenses. However the locations of most of the lenses are poorly defined. The SuperMacho project will detect and follow up {approx}60 microlensing events exhibiting special properties due to binarity, etc., will allow us to better determine the location and nature of the lenses causing the LMC microlensing events.

  17. The First Heroic Decade of Microlensing

    CERN Document Server

    Evans, N W

    2003-01-01

    We review the fundamentals of vanilla and exotic microlensing. Deviations from the standard form of an achromatic, time-symmetric lightcurve can be caused by the parallax and xallarap effects, finite source size effects and binarity. The pioneering experiments of MACHO, EROS and OGLE reported first candidate events exactly ten years ago, so now is an opportune moment to summarise the achievements of the First Heroic Decade. Three applications are reviewed in detail -- namely (i) searches for compact dark objects in the Galactic halo, (ii) probes of the baryonic mass distribution in the inner Galaxy and the Andromeda Galaxy and (iii) studies of the limb darkening of source stars. Finally, we suggest four projects for the Second Heroic Decade -- (i) K band microlensing towards the Bulge, (ii) pixel lensing towards the low luminosity spiral galaxy M33, (iii) polarimetry of on-going microlensing events and (iv) astrometric microlensing with the GAIA satellite.

  18. Evidence of Halo Microlensing in M31

    CERN Document Server

    Uglesich, R R; Baltz, E A; De Jong, J T A; Boyle, R P; Corbally, C J; Uglesich, Robert R.; Crotts, Arlin P.S.; Baltz, Edward A.; Jong, Jelte T.A. de; Boyle, Richard P.; Corbally, Christopher J.

    2004-01-01

    We report results from intensive monitoring of two fields on either side of M31,emphasizing microlensing involving stars and masses in M31. These results stem from the three-year VATT/Columbia survey of variability on 3d to 2m timescales. Observations were conducted intensively from 1997-1999, with baselines 1995-now,at the Vatican Advanced Technology Telescope, MDM 1.3-meter, and Isaac Newton telescopes, totaling about 200 epochs. The two fields cover 560 square arcmin total, along the minor axis on either side of M31. Candidate microlensing events are subject to tests to distinguish microlenses from variable stars. Fourprobable microlensing events total, compared to carefully computed event rate and efficiency models, indicate a marginally significant microlensing activity above expectations for the stellar lenses alone in M31 (and the Galaxy) acting as lenses. Maximum likelihood analyses of the event distribution in timescale and across the face of M31 indicates a microlensing dark matter halo fraction con...

  19. Microlensing detection of extrasolar planets.

    Science.gov (United States)

    Giannini, Emanuela; Lunine, Jonathan I

    2013-05-01

    We review the method of exoplanetary microlensing with a focus on two-body planetary lensing systems. The physical properties of planetary systems can be successfully measured by means of a deep analysis of lightcurves and high-resolution imaging of planetary systems, countering the concern that microlensing cannot determine planetary masses and orbital radii. Ground-based observers have had success in diagnosing properties of multi-planet systems from a few events, but space-based observations will be much more powerful and statistically more complete. Since microlensing is most sensitive to exoplanets beyond the snow line, whose statistics, in turn, allow for testing current planetary formation and evolution theories, we investigate the retrieval of semi-major axis density by a microlensing space-based survey with realistic parameters. Making use of a published statistical method for projected exoplanets quantities (Brown 2011), we find that one year of such a survey might distinguish between simple power-law semi-major axis densities. We conclude by briefly reviewing ground-based results hinting at a high abundance of free-floating planets and describing the potential contribution of space-based missions to understanding the frequency and mass distribution of these intriguing objects, which could help unveil the formation processes of planetary systems.

  20. OGLE-2012-BLG-0455/MOA-2012-BLG-206: Microlensing event with ambiguity in planetary interpretations caused by incomplete coverage of planetary signal

    CERN Document Server

    Park, H; Gould, A; Udalski, A; Sumi, T; Fouqué, P; Choi, J -Y; Christie, G; Depoy, D L; Dong, Subo; Gaudi, B S; Hwang, K -H; Jung, Y K; Kavka, A; Lee, C -U; Monard, L A G; Natusch, T; Ngan, H; Pogge, R W; Shin, I -G; Yee, J C; Szymański, M K; Kubiak, M; Soszyński, I; Pietrzyński, G; Poleski, R; Ulaczyk, K; Pietrukowicz, P; Kozłowski, S; Skowron, J; Wyrzykowski, Ł; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Chote, P; Freeman, M; Fukui, A; Fukunaga, D; Harris, P; 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; Wada, K; Yamai, N; Yock, P C M; Yonehara, A

    2014-01-01

    Characterizing a microlensing planet is done from modeling an observed lensing light curve. In this process, it is often confronted that solutions of different lensing parameters result in similar light curves, causing difficulties in uniquely interpreting the lens system, and thus understanding the causes of different types of degeneracy is important. In this work, we show that incomplete coverage of a planetary perturbation can also result in degenerate solutions even for events where the planetary signal is detected with a high level of statistical significance. We demonstrate the degeneracy for an actually observed event OGLE-2012-BLG-0455/MOA-2012-BLG-206. The peak of this high-magnification event $(A_{\\rm max}\\sim400)$ exhibits very strong deviation from a point-lens model with $\\Delta\\chi^{2}\\gtrsim4000$. From detailed modeling of the light curve, we find that the deviation can be explained by four distinct solutions, i.e., two very different sets of solutions, each with a two-fold degeneracy. While th...

  1. Microlensing Events by Proxima Centauri in 2014 and 2016: Opportunities for Mass Determination and Possible Planet Detection

    CERN Document Server

    Sahu, Kailash C; Anderson, Jay; Dominik, Martin

    2014-01-01

    We have found that Proxima Centauri, the star closest to our Sun, will pass close to a pair of faint background stars in the next few years. Using Hubble Space Telescope (HST) images obtained in 2012 October, we determine that the passage close to a mag 20 star will occur in 2014 October (impact parameter 1.6"), and to a mag 19.5 star in 2016 February (impact parameter 0.5"). As Proxima passes in front of these stars, the relativistic deflection of light will cause shifts in the positions of the background stars by ~0.5 and 1.5 mas, respectively, readily detectable by HST imaging, and possibly by Gaia and ground-based facilities such as VLT. Measurement of these astrometric shifts offers a unique and direct method to measure the mass of Proxima. Moreover, if Proxima has a planetary system, the planets may be detectable through their additional microlensing signals, although the probability of such detections is small. With astrometric accuracies of 0.03 mas (achievable with HST spatial scanning), centroid shi...

  2. OGLE-2012-BLG-0455/MOA-2012-BLG-206: Microlensing event with ambiguity in planetary interpretations caused by incomplete coverage of planetary signal

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.; Han, C.; Choi, J.-Y.; Hwang, K.-H.; Jung, Y. K.; Shin, I.-G. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Gould, A.; Gaudi, B. S.; Kavka, A.; Pogge, R. W. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Fouqué, P. [IRAP, CNRS, Université de Toulouse, F-31400 Toulouse (France); Christie, G.; Natusch, T.; Ngan, H. [Auckland Observatory, Auckland (New Zealand); Depoy, D. L. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Dong, Subo [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Road 5, Hai Dian District, Beijing 100871 (China); Lee, C.-U. [Korea Astronomy and Space Science Institute, 776 Daedukdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Monard, L. A. G. [Kleinkaroo Observatory, Calitzdorp, and Bronberg Observatory, Pretoria (South Africa); Collaboration: μFUN Collaboration; OGLE Collaboration; MOA Collaboration; and others

    2014-05-20

    Characterizing a microlensing planet is done by modeling an observed lensing light curve. In this process, it is often confronted that solutions of different lensing parameters result in similar light curves, causing difficulties in uniquely interpreting the lens system, and thus understanding the causes of different types of degeneracy is important. In this work, we show that incomplete coverage of a planetary perturbation can result in degenerate solutions even for events where the planetary signal is detected with a high level of statistical significance. We demonstrate the degeneracy for an actually observed event OGLE-2012-BLG-0455/MOA-2012-BLG-206. The peak of this high-magnification event (A {sub max} ∼ 400) exhibits very strong deviation from a point-lens model with Δχ{sup 2} ≳ 4000 for data sets with a total of 6963 measurements. From detailed modeling of the light curve, we find that the deviation can be explained by four distinct solutions, i.e., two very different sets of solutions, each with a twofold degeneracy. While the twofold (so-called close/wide) degeneracy is well understood, the degeneracy between the radically different solutions is not previously known. The model light curves of this degeneracy differ substantially in the parts that were not covered by observation, indicating that the degeneracy is caused by the incomplete coverage of the perturbation. It is expected that the frequency of the degeneracy introduced in this work will be greatly reduced with the improvement of the current lensing survey and follow-up experiments and the advent of new surveys.

  3. Hubble Space Telescope Discovery of a Probable Caustic-Crossing Event in the MACS1149 Galaxy Cluster Field

    Science.gov (United States)

    Kelly, Patrick L.; Rodney, Steven; Diego, Jose Maria; Zitrin, Adi; Broadhurst, Tom; Selsing, Jonatan; Balestra, Italo; Benito, Alberto Molino; Bradac, Marusa; Bradley, Larry; Brammer, Gabriel; Cenko, Brad; Christensen, Lise; Coe, Dan; Filippenko, Alexei V.; Foley, Ryan; Frye, Brenda; Graham, Melissa; Graur, Or; Grillo, Claudio; Hjorth, Jens; Howell, Andy; Jauzac, Mathilde; Jha, Saurabh; Kaiser, Nick; Kawamata, Ryota; Kneib, Jean-Paul; Lotz, Jennifer; Matheson, Thomas; McCully, Curtis; Merten, Julian; Nonino, Mario; Oguri, Masamune; Richard, Johan; Riess, Adam; Rosati, Piero; Schmidt, Kasper Borello; Sharon, Keren; Smith, Nathan; Strolger, Lou; Treu, Tommaso; Wang, Xin; Weiner, Ben; Williams, Liliya; Zheng, Weikang

    2016-05-01

    While monitoring the MACS1149 (z = 0.54) galaxy cluster as part of the RefsdalRedux program (PID 14199; PI Kelly) with the Hubble Space Telescope (HST) WFC3 IR camera, we have detected a rising transient that appears to be coincident ( Target-of-opportunity optical follow-up imaging in several ACS and WFC3 bands with the FrontierSN program (PID 14208; PI Rodney) has revealed that its rest-frame ultraviolet through optical spectrum may be reasonably well fit with that of a B star at z=1.49 exhibiting a strong Balmer break.

  4. K2 Microlensing and Campaign 9

    Science.gov (United States)

    Penny, Matthew

    2016-06-01

    Campaign 9 of K2 will observe a contiguous 3.7 deg^2 region of the Galactic bulge in order to search for microlensing events and measure microlens parallaxes. It will also perform targeted follow-up of approximately 50 microlensing events spread throughout the Kepler focal plane. Parallax measurements are a critical ingredient for measurements of both the lens mass and distance, which contribute to our understanding of the formation of cold exoplanets, and the formation of planets as a function of Galactic environment. Additionally, as the first un-targeted, space-based microlensing survey, K2C9 offers us the first chance to measure the masses and kinematics of a large population of free-floating planet candidates, whose large abundance has been a puzzle since their discovery.I will review the scientific goals of the K2C9 survey, which will be well underway, and report on the ongoing activity of the K2 Campaign 9 Microlensing Science Team and the wider microlensing community, with a focus on the progress that has been made towards analyzing K2 data in crowded fields.

  5. Microlensing, Brown Dwarfs and GAIA

    CERN Document Server

    Evans, N W

    2014-01-01

    The GAIA satellite can precisely measure the masses of nearby brown dwarfs and lower main sequence stars by the microlensing effect. The scientific yield is maximised if the microlensing event is also followed with ground-based telescopes to provide densely sampled photometry. There are two possible strategies. First, ongoing events can be triggered by photometric or astrometric alerts by GAIA. Second, events can be predicted using known high proper motion stars as lenses. This is much easier, as the location and time of an event can be forecast. Using the GAIA source density, we estimate that the sample size of high proper motion ($>300$ mas yr$^{-1}$) brown dwarfs needed to provide predictable events during the 5 year mission lifetime is surprisingly small, only of the order of a hundred. This is comparable to the number of high proper motion brown dwarfs already known from the work of the UKIDSS Large Area Survey and the all-sky WISE satellite. Provided the relative parallax of the lens and the angular Ein...

  6. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing...... masses of the brown dwarf companions are 0.02 ± 0.01 M⊙ and 0.019 ± 0.002 M⊙ for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events...

  7. Stellar rotation effects in polarimetric microlensing

    CERN Document Server

    Sajadian, Sedighe

    2016-01-01

    It is well known that the polarization signal in microlensing events of hot stars is larger than that of main-sequence stars. Most hot stars rapidly rotate around their stellar axes. The stellar rotation makes ellipticity and gravity-darkening effects which break the spherical symmetry of the source shape and the circular symmetry of the source surface brightness respectively. Hence, it causes a net polarization signal for the source star. This polarization signal should be considered in polarimetry microlensing of fast rotating stars. For moderate rotating stars, lensing can magnify or even characterize small polarization signals due to the stellar rotation through polarimetry observations. The gravity-darkening effect due to a rotating source star makes asymmetric perturbations in polarimetry and photometry microlensing curves whose maximum happens when the lens trajectory crosses the projected position of the rotation pole on the sky plane. The stellar ellipticity makes a time shift (i) in the position of ...

  8. Discovering Extrasolar Planets with Microlensing Surveys

    Science.gov (United States)

    Wambsganss, J.

    2016-06-01

    An astronomical survey is commonly understood as a mapping of a large region of the sky, either photometrically (possibly in various filters/wavelength ranges) or spectroscopically. Often, catalogs of objects are produced/provided as the main product or a by-product. However, with the advent of large CCD cameras and dedicated telescopes with wide-field imaging capabilities, it became possible in the early 1990s, to map the same region of the sky over and over again. In principle, such data sets could be combined to get very deep stacked images of the regions of interest. However, I will report on a completely different use of such repeated maps: Exploring the time domain for particular kinds of stellar variability, namely microlens-induced magnifications in search of exoplanets. Such a time-domain microlensing survey was originally proposed by Bohdan Paczynski in 1986 in order to search for dark matter objects in the Galactic halo. Only a few years later three teams started this endeavour. I will report on the history and current state of gravitational microlensing surveys. By now, routinely 100 million stars in the Galactic Bulge are monitored a few times per week by so-called survey teams. All stars with constant apparent brightness and those following known variability patterns are filtered out in order to detect the roughly 2000 microlensing events per year which are produced by stellar lenses. These microlensing events are identified "online" while still in their early phases and then monitored with much higher cadence by so-called follow-up teams. The most interesting of such events are those produced by a star-plus-planet lens. By now of order 30 exoplanets have been discovered by these combined microlensing surveys. Microlensing searches for extrasolar planets are complementary to other exoplanet search techniques. There are two particular advantages: The microlensing method is sensitive down to Earth-mass planets even with ground-based telecopes, and it

  9. Searching gravitational microlensing events in the galaxy spiral arms by EROS II; Recherche d'evenements de microlentille gravitationnelle dans les bras spiraux de la galaxie avec EROS II

    Energy Technology Data Exchange (ETDEWEB)

    Derue, Frederic [Paris-11 Univ., 91 Orsay (France)

    1999-04-15

    The EROS II experiment is searching for microlensing events due to compact massive objects passing through the line-of-sight of luminous stars. These objects are candidates to explain the baryonic component of Dark Matter in our Galaxy. EROS II was dedicated to different lines-of-sight: Small and Large Magellanic Clouds, Galactic Centre and 4 directions towards the Spiral Arms of the Galaxy. This thesis presents the first search for microlensing towards these last lines-of-sight (about 9 million stars). Simple criteria based on the search for significant fluctuations allowed one to discover a low noise sample of 7 candidates to the microlensing effect, with an average timescale of 50 days. A detailed analysis of the light curve of one candidate allows us to give a confidence interval on its mass 2.7 x 10{sup -3} < M/M{sub 0} < 0.84 at 95% CL. The amplification curve of another candidate shows a modulation which can be interpreted as a microlensing effect acting on a binary source, with an orbital period of P{sub 0} = 50 {+-} 3 days. To improve the knowledge of the distance of the target stars, we have combined observations of EROS II with bibliographic sources on associations of stars linked with the spiral arm features, and we have developed a program to find variable stars. Ten cepheids have thus been found. Distances obtained with different methods are in rough agreement with each other. The average optical depth measured towards the four directions is {tau}-bar = 0.45{sub 0.11}{sup +0.23} x 10{sup -6}. It is compatible with expectations from simple galactic models. The long duration of most events favours interpretation of lensing by objects belonging to the disk instead of the halo. It also seems that some events due to bulge lenses have influenced measurements towards the line-of-sight which is closest to the Galactic Centre. Observation continue towards spiral arms. More accurate measurements should be obtained with increase of statistics, allowing one to

  10. Gravitational microlensing of AGN dusty tori

    CERN Document Server

    Stalevski, Marko; Popovic, Luka C; Baes, Maarten

    2012-01-01

    We investigated gravitational microlensing of AGN dusty tori in the case of lensed quasars in the infrared domain. The dusty torus is modeled as a clumpy two-phase medium. To obtain spectral energy distributions and images of tori at different wavelengths, we used the 3D Monte Carlo radiative transfer code SKIRT. A ray-shooting technique has been used to calculate microlensing magnification maps. We simulated microlensing by the stars in the lens galaxy for different configurations of the lensed system and different values of the torus parameters, in order to estimate (a) amplitudes and timescales of high magnification events, and (b) the influence of geometrical and physical properties of dusty tori on light curves in the infrared domain. We found that, despite their large size, dusty tori could be significantly affected by microlensing in some cases, especially in the near-infrared domain (rest-frame). The very long timescales of such events, in the range from several decades to hundreds of years, are limit...

  11. Polarization and SEDs from Microlensing of Circumstellar Envelopes

    CERN Document Server

    Ignace, R; Bunker, C

    2008-01-01

    Microlensing surveys have proven to be tremendously fruitful in providing valuable data products for many fields of astrophysics, from eclipse lightcurves for substellar candidates to limb darkening in stellar atmospheres. We report on a program of modeling observables from microlensing of circumstellar envelopes, particularly those of red giant stars that are the most likely to show finite source effects. We will summarize work for how polarization light curves can be used to infer envelope properties and will describe recent modeling of the time dependent spectral energy distributions (SEDs) for microlensing of dusty winds. One of the most exciting developments is the possibility of measuring variable polarization from microlensing in a suitable source using the RINGO polarimeter at La Palma. Also quite interesting is the possibility of probing a dusty wind using IRAC data for a suitable source in the event that Spitzer has a ``warm'' cycle.

  12. Blending in Gravitational Microlensing Experiments: Source Confusion And Related Systematics

    CERN Document Server

    Smith, Martin C; Mao, Shude; Sumi, Takahiro

    2007-01-01

    Gravitational microlensing surveys target very dense stellar fields in the local group. As a consequence the microlensed source stars are often blended with nearby unresolved stars. The presence of `blending' is a cause of major uncertainty when determining the lensing properties of events towards the Galactic centre. After demonstrating empirical cases of blending we utilize Monte Carlo simulations to probe the effects of blending. We generate artificial microlensing events using an HST luminosity function convolved to typical ground-based seeing, adopting a range of values for the stellar density and seeing. We find that a significant fraction of bright events are blended, contrary to the oft-quoted assumption that bright events should be free from blending. We probe the effect that this erroneous assumption has on both the observed event timescale distribution and the optical depth, using realistic detection criteria relevent to the different surveys. Importantly, under this assumption the latter quantity ...

  13. Free-floating planets from core accretion theory: microlensing predictions

    Science.gov (United States)

    Ma, Sizheng; Mao, Shude; Ida, Shigeru; Zhu, Wei; Lin, Douglas N. C.

    2016-09-01

    We calculate the microlensing event rate and typical time-scales for the free-floating planet (FFP) population that is predicted by the core accretion theory of planet formation. The event rate is found to be ˜1.8 × 10-3 of that for the stellar population. While the stellar microlensing event time-scale peaks at around 20 d, the median time-scale for FFP events (˜0.1 d) is much shorter. Our values for the event rate and the median time-scale are significantly smaller than those required to explain the Sumi et al. result, by factors of ˜13 and ˜16, respectively. The inclusion of planets at wide separations does not change the results significantly. This discrepancy may be too significant for standard versions of both the core accretion theory and the gravitational instability model to explain satisfactorily. Therefore, either a modification to the planet formation theory is required or other explanations to the excess of short-time-scale microlensing events are needed. Our predictions can be tested by ongoing microlensing experiment such as Korean Microlensing Telescope Network, and by future satellite missions such as WFIRST and Euclid.

  14. Detecting circumstellar disks around gravitational microlenses

    CERN Document Server

    Hundertmark, M; Dreizler, S

    2009-01-01

    We investigate the chance of detecting proto-planetary or debris disks in stars that induce microlensing events (lenses). The modification of the light curves shapes due to occultation and extinction by the disks as well as the additional gravitational deflection caused by the additional mass is considered. The magnification of gravitational microlensing events is calculated using the ray shooting method. The occultation is taken into account by neglecting or weighting the images on the lens plane according to a transmission map of the corresponding disk for a point source point lens (PSPL) model. The estimated frequency of events is obtained by taking the possible inclinations and optical depths of the disk into account. We conclude that gravitational microlensing can be used, in principle, as a tool for detecting debris disks beyond 1 kpc, but estimate that each year of the order of 1 debris disk is expected for lens stars of F, G, or K spectral type and of the order of 10 debris disks might have shown sign...

  15. Expectations from a Microlensing Search for Planets

    CERN Document Server

    Peale, S J

    1996-01-01

    The statistical distribution of the masses of planets about stars between the Sun and the center of the galaxy is constrained to within a factor of three by an intensive search for planets during microlensing events. Projected separations in terms of the lens Einstein ring radius yield a rough estimate of the distribution of planetary semimajor axes with planetary mass. The search consists of following ongoing stellar microlensing events involving sources in the center of the galaxy lensed by intervening stars with high time resolution, 1% photometry in two colors in an attempt to catch any short time scale planetary perturbations of the otherwise smooth light curve. It is assumed that 3000 events are followed over an 8 year period, but with half of the lenses, those that are members of binary systems, devoid of planets. The remaining 1500 lenses have solar-system-like distributions of 4 or 5 planets. The expectations from the microlensing search are extremely assumption dependent with 56, 138, and 81 planets...

  16. Microlensing Binaries Discovered through High-magnification Channel

    DEFF Research Database (Denmark)

    Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.

    2012-01-01

    Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturba...

  17. The First Simultaneous Microlensing Observations by Two Space telescopes

    DEFF Research Database (Denmark)

    Shvartzvald, Y.; Li, Z.; Udalski, A.

    2016-01-01

    properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either ˜0.25 au or ˜45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We...

  18. The Angstrom Project Alert System: real-time detection of extragalactic microlensing

    CERN Document Server

    Darnley, M J; Newsam, A; Duke, J P; Gould, A; Han, C; Ibrahimov, M A; Im, M; Jeon, Y B; Karimov, R G; Lee, C U; Park, B G

    2006-01-01

    The Angstrom Project is undertaking an optical survey of stellar microlensing events across the bulge region of the Andromeda Galaxy (M31) using a distributed network of two-meter class telescopes. The Angstrom Project Alert System (APAS) has been developed to identify in real time candidate microlensing and transient events using data from the Liverpool and Faulkes North robotic telescopes. This is the first time that real-time microlensing discovery has been attempted outside of the Milky Way and its satellite galaxies. The APAS is designed to enable follow-up studies of M31 microlensing systems, including searches for gas giant planets in M31. Here we describe the APAS and we present a few example light curves obtained during its commissioning phase which clearly demonstrate its real-time capability to identify microlensing candidates as well as other transient sources.

  19. Microlensing modulation by binaries

    CERN Document Server

    Dubath, F; Durrer, R; Dubath, Florian; Gasparini, Maria Alice; Durrer, Ruth

    2006-01-01

    We compute the effect of the lens quadrupole on microlensing. The time dependence of the quadrupole can lead to specific modulations of the amplification signal. We study especially binary system lenses in our galaxy. The modulation is observable if the rotation period of the system is smaller than the time over which the amplification is significant and if the impact parameter of the passing light ray is sufficiently close to the Einstein radius so that the amplification is very large. Observations of this modulation can reveal important information on the quadrupole and thus on the gravitational radiation emitted by the lens.

  20. Microlensing constraints on the frequency of Jupiter-mass companions : Analysis of 5 years of PLANET photometry

    NARCIS (Netherlands)

    Gaudi, BS; Albrow, MD; An, J; Beaulieu, JP; Caldwell, JAR; DePoy, DL; Dominik, M; Gould, A; Greenhill, J; Hill, K; Kane, S; Martin, R; Menzies, J; Naber, RM; Pel, JW; Pogge, RW; Pollard, KR; Sackett, PD; Sahu, KC; Vermaak, P; Watson, R; Williams, A

    2002-01-01

    We analyze 5 years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single-lens light curves that are indicative of the presence of planetary companions to the primary microlenses. Using strict event-selection criteria, we constru

  1. Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey

    Energy Technology Data Exchange (ETDEWEB)

    Rest, A; Stubbs, C; Becker, A C; Miknaitis, G A; Miceli, A; Covarrubias, R; Hawley, S L; Smith, C; Suntzeff, N B; Olsen, K; Prieto, J; Hiriart, R; Welch, D L; Cook, K; Nikolaev, S; Proctor, G; Clocchiatti, A; Minniti, D; Garg, A; Challis, P; Keller, S C; Scmidt, B P

    2004-05-27

    Characterizing the nature and spatial distribution of the lensing objects that produce the observed microlensing optical depth toward the Large Magellanic Cloud (LMC) remains an open problem. They present an appraisal of the ability of the SuperMACHO Project, a next-generation microlensing survey pointed toward the LMC, to discriminate between various proposed lensing populations. they consider two scenarios: lensing by a uniform foreground screen of objects and self-lensing of LMC stars. The optical depth for ''screen-lensing'' is essentially constant across the face of the LMC; whereas, the optical depth for self-lensing shows a strong spatial dependence. they have carried out extensive simulations, based upon actual data obtained during the first year of the project, to assess the SuperMACHO survey's ability to discriminate between these two scenarios. In the simulations they predict the expected number of observed microlensing events for each of their fields by adding artificial stars to the images and estimating the spatial and temporal efficiency of detecting microlensing events using Monte-Carlo methods. They find that the event rate itself shows significant sensitivity to the choice of the LMC luminosity function shape and other parameters, limiting the conclusions which can be drawn from the absolute rate. By instead determining the differential event rate across the LMC, they can decrease the impact of these systematic uncertainties rendering the conclusions more robust. With this approach the SuperMACHO Project should be able to distinguish between the two categories of lens populations and provide important constraints on the nature of the lensing objects.

  2. Microlensing Search for Planets with Two Simultaneously Rising Suns

    CERN Document Server

    Han, Cheongho

    2008-01-01

    Among more than 200 extrasolar planet candidates discovered to date, there is no known planet orbiting around normal binary stars. In this paper, we demonstrate that microlensing is a technique that can detect such planets. Microlensing discoveries of these planets are possible because the planet and host binary stars produce perturbations at a common region around center of mass of the binary stars and thus the signatures of both planet and binary can be detected in the light curves of high-magnification microlensing events. The ranges of the planetary and binary separations of systems for optimal detection vary depending on the planet mass. For a Jupiter-mass planet, we find that high detection efficiency is expected for planets located in the range of $\\sim$ 1 AU -- 5 AU from the binary stars which are separated by $\\sim$ 0.15 AU -- 0.5 AU

  3. Discovering Exoplanets with Microlensing: Transition to the Next Generation

    Science.gov (United States)

    Gould, Andrew

    We propose to continue our successful program of planet discovery using the gravitaional microlensing technique. Our work will specifically focus on so-called "high- magnification events", which are exceptionally sensitive to planets, and which allow us to extract exceptionally detailed information about each planetary system. These results will be of high scientific interest in their own right, but will also play a key role in the transition to "next-generation" surveys that will discover many times more planets in "low-magnification events". We will continue to operate and build our network of approximately 30 amateur+professional astronomers (about half each) on 6 continents plus Oceania, which enables the 24 hour coverage that is crucial to extracting planetary science from microlensing events. In particular, by engaging the amateurs at a high scientific level, we will both improve the quantity and quality of amateur data and utilize their role as a "transmission belt" to the broader public. Over the past few years, high-mag events have enabled the first detection of a Jupiter- Saturn analog system, the first census of ice and gas giants beyond the snow line, the recognition that "cold Neptunes" are extremely common, and the detection of 3 very massive, super-Jupiter planets orbiting M dwarfs (which may challenge the standard "core-accretion" paradigm). Analysis of these events has also led to key theoretical insights, including the fact that planet orbital motion can be detected in microlensing events and that careful effort is required to disentangle this from "parallax effects" (due to the Earth's own orbital motion). The direct impact of our proposed work will be to increase the still small statistics of high-mag planet detections (due to the intrinsic rarity of high-mag events) and to exploit the sensitivity of these events to higher-order effects (including parallax, planet orbital motion, and multiple planets) to gain deeper knowledge of detected systems

  4. Free-floating planets from core accretion theory: microlensing predictions

    CERN Document Server

    Ma, Sizheng; Ida, Shigeru; Zhu, Wei; Lin, Douglas N C

    2016-01-01

    We calculate the microlensing event rate and typical time-scales for the free-floating planet (FFP) population that is predicted by the core accretion theory of planet formation. The event rate is found to be ~$1.8\\times 10^{-3}$ of that for the stellar population. While the stellar microlensing event time-scale peaks at around 20 days, the median time-scale for FFP events (~0.1 day) is much shorter. Our values for the event rate and the median time-scale are significantly smaller than those required to explain the \\cite{Sum+11} result, by factors of ~13 and ~16, respectively. The inclusion of planets at wide separations does not change the results significantly. This discrepancy may be too significant for standard versions of both the core accretion theory and the gravitational instability model to explain satisfactorily. Therefore, either a modification to the planet formation theory is required, or other explanations to the excess of short-time-scale microlensing events are needed. Our predictions can be t...

  5. Polarization in microlensing towards the Galactic bulge

    CERN Document Server

    Ingrosso, G; De Paolis, F; Jetzer, Ph; Nucita, A A; Strafella, F; Zakharov, A F

    2012-01-01

    Gravitational microlensing, when finite size source effects are relevant, provides an unique tool for the study of source star stellar atmospheres through an enhancement of a characteristic polarization signal. This is due to the differential magnification induced during the crossing of the source star. In this paper we consider a specific set of reported highly magnified, both single and binary exoplanetary systems, microlensing events towards the Galactic bulge and evaluate the expected polarization signal. To this purpose, we consider several polarization models which apply to different types of source stars: hot, late type main sequence and cool giants. As a result we compute the polarization signal P,which goes up to P=0.04% for late type stars and up to a few percent for cool giants, depending on the underlying physical polarization processes and atmosphere model parameters. Given a I band magnitude at maximum magnification of about 12, and a typical duration of the polarization signal up to 1 day, we c...

  6. Probing Galactic structure using micro-lensing with EROS-2

    CERN Document Server

    Ansari, R

    1999-01-01

    EROS has been monitoring few million stars in the Magellanic clouds, as well as toward the Galactic bulge and spiral arms since 1996, to search for microlensing events. In this paper, we present briefly the EROS setup and scientific program and discuss the results obtained from our observations in four directions in the Galactic plane, away from the bulge. Seven light curves, out of 9.1 million stars observed in these directions show luminosity variations interpreted as due to microlensing. The averaged estimated optical depth tau = 0.45 +0.24 -0.11 is compatible with expectations from simple Galactic models. Nonetheless a small excess of short time-scale events may be present in the direction closest to the Galactic center.

  7. Mass Measurements of Isolated Objects from Space-based Microlensing

    Science.gov (United States)

    Zhu, Wei; Calchi Novati, S.; Gould, A.; Udalski, A.; Han, C.; Shvartzvald, Y.; Ranc, C.; Jørgensen, U. G.; Poleski, R.; Bozza, V.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Pogge, R. W.; Porritt, I.; Wibking, B.; Yee, J. C.; SPITZER Team; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Pietrukowicz, P.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; OGLE Group; Choi, J.-Y.; Park, H.; Jung, Y. K.; Shin, I.-G.; Albrow, M. D.; Park, B.-G.; Kim, S.-L.; Lee, C.-U.; Cha, S.-M.; Kim, D.-J.; Lee, Y.; KMTNET Group; Friedmann, M.; Kaspi, S.; Maoz, D.; WISE Group; Hundertmark, M.; Street, R. A.; Tsapras, Y.; Bramich, D. M.; Cassan, A.; Dominik, M.; Bachelet, E.; Dong, Subo; Figuera Jaimes, R.; Horne, K.; Mao, S.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; RoboNeT Team; Skottfelt, J.; Andersen, M. I.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Gu, S.-H.; Hinse, T. C.; Kerins, E.; Korhonen, H.; Kuffmeier, M.; Mancini, L.; Peixinho, N.; Popovas, A.; Rabus, M.; Rahvar, S.; Tronsgaard, R.; Scarpetta, G.; Southworth, J.; Surdej, J.; von Essen, C.; Wang, Y.-B.; Wertz, O.; MiNDSTEP Group

    2016-07-01

    We report on the mass and distance measurements of two single-lens events from the 2015 Spitzer microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is very likely a brown dwarf (BD). Assuming that the source star lies behind the same amount of dust as the Bulge red clump, we find the lens is a 45 ± 7 {M}{{J}} BD at 5.9 ± 1.0 kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a 0.50 ± 0.04 {M}⊙ star at 6.9 ± 1.0 kpc. We show that the probability to definitively measure the mass of isolated microlenses is dramatically increased once simultaneous ground- and space-based observations are conducted.

  8. Microlensing by Kuiper, Oort, and Free-Floating Planets

    CERN Document Server

    Gould, Andrew

    2016-01-01

    Microlensing is generally thought to probe planetary systems only out to a few Einstein radii. Microlensing events generated by bound planets beyond about 10 Einstein radii generally do not yield any trace of their hosts, and so would be classified as free floating planets (FFPs). I show that it is already possible, using adaptive optics (AO), to constrain the presence of potential hosts to FFP candidates at separations comparable to the Oort Cloud. With next-generation telescopes, planets at Kuiper-Belt separations can be probed. Next generation telescopes will also permit routine vetting for all FFP candidates, simply by obtaining second epochs 4-8 years after the event. At present, the search for such hosts is restricted to within the "confusion limit" of theta_confus ~ 250 mas, but future WFIRST observations will allow one to probe beyond this confusion limit as well.

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

    DEFF Research Database (Denmark)

    Bozza, V.; Dominik, M.; Rattenbury, N. J.

    2012-01-01

    The microlensing event OGLE‐2008‐BLG‐510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary......‐lens and binary‐source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrate that: (1) automated real‐time detection of weak microlensing anomalies with immediate feedback is feasible...

  10. MASS MEASUREMENTS OF ISOLATED OBJECTS FROM SPACE-BASED MICROLENSING

    DEFF Research Database (Denmark)

    Zhu, Wei; Novati, S. Calchi; Gould, A.

    2016-01-01

    lies behind the same amount of dust as the Bulge red clump, we find the lens is a 45 ± 7 {M}{{J}} BD at 5.9 ± 1.0 kpc. The lens of of the second event, OGLE-2015-BLG-0763, is a 0.50 ± 0.04 {M}⊙ star at 6.9 ± 1.0 kpc. We show that the probability to definitively measure the mass of isolated microlenses...

  11. First microlensing candidate towards M31 from Nainital Microlensing Survey

    CERN Document Server

    Joshi, Y C; Narasimha, D; Sagar, R

    2004-01-01

    We report our first microlensing candidate NMS-E1 towards M31 from the data accumulated during four years long Nainital Microlensing Survey. Cousin R and I band observations of ~13'x13' field in the direction of M31 were carried out since 1998 and data is analysed using pixel technique proposed by the AGAPE collaboration. The NMS-E1 lies in the disk of M31 at \\alpha = 0:43:33.3 and \\delta = +41:06:44, about 15.5 arcmin away in the South-East direction from the center of M31. The degenerate Paczy\\'{n}ski fit gives a half intensity duration of ~ 59 days. The photometric analysis of candidate shows that it reached up to R ~ 20.1 mag at the time of maximum brightness and colour of the source star estimated to be (R-I)_0 ~ 1.1 mag. It is seen that the microlensing candidate is blended by red variable stars consequently light curves do not strictly follow the characteristic Paczy\\'{n}ski shape and achromatic nature however its long period monitoring and similar behaviour in R and I bands lend support of its microle...

  12. Planet Sensitivity from Combined Ground- and Space-based Microlensing Observations

    CERN Document Server

    Zhu, Wei; Beichman, Charles; Novati, Sebastiano Calchi; Carey, Sean; Gaudi, B Scott; Henderson, Calen B; Penny, Matthew; Shvartzvald, Yossi; Yee, Jennifer C; Udalski, A; Poleski, R; Skowron, J; Kozlowski, S; Mroz, P; Pietrukowicz, P; Pietrzynski, G; Szymanski, M K; Soszynski, I; Ulaczyk, K; Wyrzykowski, L; Abe, F; Barry, R K; Bennett, D P; Bhattacharya, A; Fukunaga, D; Inayama, K; Koshimoto, N; Namba, S; Sumi, T; Suzuki, D; Tristram, P J; Wakiyama, Y; Yonehara, A; Maoz, D; Kaspi, S; Friedmann, M

    2015-01-01

    To move one step forward toward a Galactic distribution of planets, we present the first planet sensitivity analysis for microlensing events with simultaneous observations from space and the ground. We present this analysis for two such events, OGLE-2014-BLG-0939 and OGLE-2014-BLG-0124, which both show substantial planet sensitivity even though neither of them reached high magnification. This suggests that an ensemble of low to moderate magnification events can also yield significant planet sensitivity and therefore probability to detect planets. The implications of our results to the ongoing and future space-based microlensing experiments to measure the Galactic distribution of planets are discussed.

  13. Space based microlensing planet searches

    Directory of Open Access Journals (Sweden)

    Tisserand Patrick

    2013-04-01

    Full Text Available The discovery of extra-solar planets is arguably the most exciting development in astrophysics during the past 15 years, rivalled only by the detection of dark energy. Two projects unite the communities of exoplanet scientists and cosmologists: the proposed ESA M class mission EUCLID and the large space mission WFIRST, top ranked by the Astronomy 2010 Decadal Survey report. The later states that: “Space-based microlensing is the optimal approach to providing a true statistical census of planetary systems in the Galaxy, over a range of likely semi-major axes”. They also add: “This census, combined with that made by the Kepler mission, will determine how common Earth-like planets are over a wide range of orbital parameters”. We will present a status report of the results obtained by microlensing on exoplanets and the new objectives of the next generation of ground based wide field imager networks. We will finally discuss the fantastic prospect offered by space based microlensing at the horizon 2020–2025.

  14. Mass Measurements of Isolated Objects from Space-based Microlensing

    CERN Document Server

    Zhu, Wei; Gould, A; Udalski, A; Han, C; Shvartzvald, Y; Ranc, C; Jorgensen, U G; Poleski, R; Bozza, V; Beichman, C; Bryden, G; Carey, S; Gaudi, B S; Henderson, C B; Pogge, R W; Porritt, I; Wibking, B; Yee, J C; Pawlak, M; Szymanski, M K; Skowron, J; Mroz, P; Kozlowski, S; Wyrzykowski, L; Pietrukowicz, P; Pietrzynski, G; Soszynski, I; Ulaczyk, K; Choi, J Y; Park, H; Jung, Y K; Shin, I -G; Albrow, M D; Park, B -G; Kim, S -L; Lee, C -U; Kim, D -J; Lee, Y; Friedmann, M; Kaspi, S; Maoz, D; Hundertmark, M; Street, R A; Tsapras, Y; Bramich, D M; Cassan, A; Dominik, M; Bachelet, E; Dong, Subo; Jaimes, R Figuera; Horne, K; Mao, S; Menzies, J; Schmidt, R; Snodgrass, C; Steele, I A; Wambsganss, J; Skottfelt, J; Andersen, M I; Burgdorf, M J; Ciceri, S; D'Ago, G; Evans, D F; Gu, S -H; Hinse, T C; Kerins, E; Korhonen, H; Kuffmeier, M; Mancini, L; Peixinho, N; popovas, A; Rabus, M; Rahvar, S; Rasmussen, R T; Scarpetta, G; Southworth, J; Surdej, J; von Essen, C; Wang, Y -B; Wertz, O

    2015-01-01

    We report on the mass and distance measurements of two single-lens events from the 2015 \\emph{Spitzer} microlensing campaign. With both finite-source effect and microlens parallax measurements, we find that the lens of OGLE-2015-BLG-1268 is a $47\\pm7$ $M_{\\rm J}$ brown dwarf at $5.4\\pm1.0$ kpc, and that the lens of OGLE-2015-BLG-0763 is a $0.50\\pm0.04$ $M_\\odot$ star at $6.9\\pm1.0$ kpc. We show that the probability to definitively measure the mass of isolated microlenses, including isolated stellar mass black holes and free floating planets, is dramatically increased once simultaneous ground- and space-based observations are conducted.

  15. Evidence of halo microlensing in M31

    NARCIS (Netherlands)

    Uglesich, RR; Crotts, APS; Baltz, EA; de Jong, J; Boyle, RP; Corbally, CJ

    2004-01-01

    We have completed an intensive monitoring program of two fields on either side of the center of M31 and report here on the results concerning microlensing of stars in M31. These results stem from a 3 yr study ( the Vatican Advanced Technology Telescope [VATT]/Columbia survey) of microlensing and var

  16. Using HST to Detect Isolated Black Holes and Neutron Stars through Astrometric Microlensing

    Science.gov (United States)

    Sahu, Kailash C.; Albrow, M.; Anderson, J.; Bond, H. E.; Bond, I.; Brown, T. M.; Casertano, S.; Dominik, M.; Ferguson, H. C.; Fryer, C.; Livio, M.; Mao, S.; Perrott, Y.; Udalski, A.; Yock, P.

    2012-05-01

    To date, Black Hole (BH) and Neutron Star (NS) masses have been directly measured only in binaries; no isolated stellar-mass BH has been detected unambiguously within our Galaxy. We have underway a large, 3-year HST program (192 orbits) designed to detect microlensing events caused by non-luminous isolated BHs and NSs in the direction of the Galactic bulge. Our program consists of monitoring of 12 fields in the Sagittarius window of the Galactic bulge, containing a total of 1.5 million stars down to V=28. Our observations have a typical cadence of one observation every two weeks, and are primarily targeted towards detecting microlensing events caused by non-luminous isolated BHs and NSs in the Galactic disk and bulge. The unique capability of HST imaging for microlensing observations is the addition of high-precision astrometry, allowing detection of the astrometric shift of the source during the event. Combined with the lens parallax, which can be determined from the light curve as measured by HST (and supplemented by GEMINI) observations, the astrometric shift provides a direct measurement of the lens mass. Our program is optimized to detect long-duration events, which are more likely to be caused by massive lenses. We expect to detect a few dozen long-duration microlensing events, of which 45% will show astrometric deflections, leading to direct determinations of the lens masses.

  17. Microlensing due to both gravitation and refraction as a further probe of universe evolution

    CERN Document Server

    Cavalleri, G; Tonni, E; Covino, S

    2016-01-01

    Microlensings events are predicted for the light coming from cosmological sources. In addition to the microlensing due to gravitation lensing, microlensing produced also by refraction of light due to either ionized, or not, gas clouds can be considered. A detailed prediction is here given assuming that the ray of light coming from the distant source traverses a gas cloud with a King's density profile for various possible environments. We conclude that the additional deviation due to relativistic refraction is in most cases negligible compared to the gravitational deviation. Deviation due to refraction can anyway become an interesting analysis tool for future facility with great resolving power and the effects can be singled out with dedicated surveys.

  18. The OGLE-III planet detection efficiency from six years of microlensing observations (2003 to 2008)

    CERN Document Server

    Tsapras, Y; Wyrzykowski, Ł; Horne, K; Udalski, A; Snodgrass, C; Street, R; Bramich, D M; Dominik, M; Bozza, V; Jaimes, R Figuera; Kains, N; Skowron, J; Szymański, M K; Pietrzyński, G; Soszyński, I; Ulaczyk, K; Kozłowski, S; Pietrukowicz, P; Poleski, R

    2016-01-01

    We use six years (2003 to 2008) of Optical Gravitational Lensing Experiment III microlensing observations to derive the survey detection efficiency for a range of planetary masses and projected distances from the host star. We perform an independent analysis of the microlensing light curves to extract the event parameters and compute the planet detection probability given the data. 2433 light curves satisfy our quality selection criteria and are retained for further processing. The aggregate of the detection probabilities over the range explored yields the expected number of microlensing planet detections. We employ a Galactic model to convert this distribution from dimensionless to physical units, \\alpha/au and M_E. The survey sensitivity to small planets is highest in the range 1 to 4 au, shifting to slightly larger separations for more massive ones.

  19. First microlens mass measurement : Planet photometry of EROS BLG-2000-5

    NARCIS (Netherlands)

    An, JH; Albrow, MD; Beaulieu, JP; Caldwell, JAR; DePoy, DL; Dominik, M; Gaudi, BS; Gould, A; Greenhill, J; Hill, K; Kane, S; Martin, R; Menzies, J; Pogge, RW; Pollard, KR; Sackett, PD; Sahu, KC; Vermaak, P; Watson, R; Williams, A

    2002-01-01

    We analyze PLANET photometric observations of the caustic-crossing binary lens microlensing event, EROS BLG-2000-5, and find that modeling the observed light curve requires incorporation of the microlens parallax and the binary orbital motion. The projected Einstein radius ((r) over tilde (E) = 3.61

  20. Gravitational Microlensing of Earth-mass Planets

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West

    , i.e. it is much easier to detect high mass planets in close orbits. With these two methods it is hard to detect planets in an exo-solar system with a structure similar to our own solar system; specifically, it is hard to detect Earth-like planets in Earth-like orbits. It is presently unknown how...... to the time duration of the signal, not the signal amplitude, rendering it critical to sample ongoing events very densely in time to detect Earth-mass planets. The lower limit of planet mass that will give rise to a signal is set by the angular size of the source which illuminates the lensing system. It can...... be shown that in the crowded fields where microlensing is observed, the primary obstacle for detecting Earth-mass planets is the crowding, rendering it hard to extract accurate photometry from faint sources at seeing limited resolutions. As all the sources tend to be at approximately the same distance...

  1. Astrometric Microlensing by Local Dark Matter Subhalos

    CERN Document Server

    Erickcek, Adrienne L

    2010-01-01

    High-resolution N-body simulations of dark matter halos indicate that the Milky Way contains numerous subhalos. When a dark matter subhalo passes in front of a star, the light from that star will be deflected by gravitational lensing, leading to a small change in the star's apparent position. This astrometric microlensing signal depends on the inner density profile of the subhalo and can be greater than a few microarcseconds for an intermediate-mass subhalo (Mvir > 10000 solar masses) passing within arcseconds of a star. Current and near-future instruments could detect this signal, and we evaluate SIM's, Gaia's, and ground-based telescopes' potential as subhalo detectors. We develop a general formalism to calculate a subhalo's astrometric lensing cross section over a wide range of masses and density profiles, and we calculate the lensing event rate by extrapolating the subhalo mass function predicted by simulations down to the subhalo masses potentially detectable with this technique. We find that, although t...

  2. Finite source effects in microlensing: A precise, easy to implement, fast and numerical stable formalism

    CERN Document Server

    Lee, C -H; Seitz, S; Bender, R

    2009-01-01

    The goal of this paper is to provide a numerically fast and stable description for the microlensing magnification of an extended source (either uniform or limb darkened) that holds in any magnification regime. We show that our method of evaluating the magnification can be implemented into a light curve fitting routine using the Levenberg-Marquardt algorithm. We compare the accuracy and computation times to previous methods that either work in the high magnification regime only, or have a numerical instability problem due to the evaluation of an elliptic integral. In addition we also provide the equations including finite lens effects in microlensing light curves. We apply our methods to the MACHO-1995-BLG-30 and the OGLE-2003-BLG-262 events and obtain results consistent to former studies. We derive an upper limit for the OGLE-2003-BLG-262 event lens size. We conclude that our method allows to simultaneously search for point-source and finite source microlensing events in future large area microlensing surveys...

  3. A theoretical calculation of microlensing signatures caused by free-floating planets towards the Galactic bulge

    CERN Document Server

    Hamolli, L; Nucita, A A

    2014-01-01

    Free-floating planets are recently drawing a special interest of the scientific community. Gravitational microlensing is up to now the exclusive method for the investigation of free-floating planets, including their spatial distribution function and mass function. In this work, we examine the possibility that the future Euclid space-based observatory may allow to discover a substantial number of microlensing events caused by free-floating planets. Based on latest results about the free-floating planet mass function in the mass range $[10^{-5}, 10^{-2}]M_{\\odot}$, we calculate the optical depth towards the Galactic bulge as well as the expected microlensing rate and find that Euclid may be able to detect hundreds to thousands of these events per month. Making use of a synthetic population, we also investigate the possibility of detecting parallax effect in simulated microlensing events due to free-floating planets and find a significant efficiency for the parallax detection that turns out to be around 30%.

  4. Direct Laser Printing of Tailored Polymeric Microlenses.

    Science.gov (United States)

    Florian, Camilo; Piazza, Simonluca; Diaspro, Alberto; Serra, Pere; Duocastella, Martí

    2016-07-13

    We report a laser-based approach for the fast fabrication of high-optical-quality polymeric microlenses and microlens arrays with controllable geometry and size. Our strategy consists of the direct laser printing of microdroplets of a highly viscous UV prepolymer at targeted positions, followed by photocuring. We study the morphological characteristics and imaging performance of the microlenses as a function of the substrate and laser parameters and investigate optimal printing conditions and printing mechanisms. We show that the microlens size and focusing properties can be easily tuned by the laser pulse energy, with minimum volumes below 20 fL and focal lengths ranging from 7 to 50 μm.

  5. Finding Free-Floating Black Holes using Astrometric Microlensing

    Science.gov (United States)

    Lu, Jessica R.; Ofek, Eran Oded; Sinukoff, Evan; Udalski, Andrzej; Kozlowski, Szymon

    2017-01-01

    Our Galaxy most likely hosts 10-100 million stellar mass black holes. The exact number and mass function of these black holes contains important information regarding our Galaxy's star formation history, stellar mass function, and the fate of very massive stars. However, isolated stellar black holes have yet to be detected. To date, stellar mass black holes have only been definitively detected in binary systems with accreting companions or merging to produce gravitational waves. In principle, the presence of isolated black holes can be inferred from astrometric and photometric signatures produced when they lens light from a background star. We attempt to detect the astrometric lensing signatures of several photometrically identified microlensing events, toward the Galactic Bulge. Long-duration events (t_Einstein > 100 days) were selected as the most likely black hole candidates and were observed using several years of laser-guided adaptive optics observations from the W. M. Keck telescopes. We present results from this search.

  6. Searching for Frozen Super Earth via Microlensing

    Science.gov (United States)

    Batista, V.; Beaulieu, J. P.; Cassan, A.; Coutures, C.; Donatowicz, J.; Fouqué, P.; Kubas, D.; Marquette, J. B.

    2009-04-01

    Microlensing planet hunt is a unique method to probe efficiently for frozen Super Earth orbiting the most common stars of our galaxy. It is nicely complementing the parameter space probed by very high accuracy radial velocity measurements and future space based detections of low mass transiting planets. In order to maximize the planet catch, the microlensing community is engaged in a total cooperation among the different groups (OGLE, MicroFUN, MOA, PLANET/RoboNET) by making the real time data available, and mutual informing/reporting about modeling efforts. Eight planets have been published so far by combinations of the different groups, 4 Jovian analogues, one Neptune and two Super Earth. Given the microlensing detection efficiency, it suggests that these Neptunes/Super Earths may be quite common. Using networks of dedicated 1-2m class telescopes, the microlensing community has entered a new phase of planet discoveries, and will be able to provide constraints on the abundance of frozen Super-Earths in the near future. Statistics about Mars to Earth mass planets, extending to the habitable zone will be achieved with space based wide field imagers (EUCLID) at the horizon 2017.

  7. Detection of Extrasolar Planets by Gravitational Microlensing

    CERN Document Server

    Bennett, David P

    2009-01-01

    Gravitational microlensing provides a unique window on the properties and prevalence of extrasolar planetary systems because of its ability to find low-mass planets at separations of a few AU. The early evidence from microlensing indicates that the most common type of exoplanet yet detected are the so-called "super-Earth" planets of ~10 Earth-masses at a separation of a few AU from their host stars. The detection of two such planets indicates that roughly one third of stars have such planets in the separation range 1.5-4 AU, which is about an order of magnitude larger than the prevalence of gas-giant planets at these separations. We review the basic physics of the microlensing method, and show why this method allows the detection of Earth-mass planets at separations of 2-3 AU with ground-based observations. We explore the conditions that allow the detection of the planetary host stars and allow measurement of planetary orbital parameters. Finally, we show that a low-cost, space-based microlensing survey can p...

  8. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  9. Detecting and Measuring the Masses of Isolated Black Holes and Neutron Stars through Astrometric Microlensing

    Science.gov (United States)

    Sahu, Kailash

    2013-10-01

    We propose a 3-year program of monitoring of 12 fields in the Galactic bulge, containing a total of 1.5 million stars down to V=28. Our primary aim is to detect microlensing events caused by non-luminous isolated black holes {BHs} and neutron stars {NSs} in the Galactic disk and bulge.The unique capability of HST imaging for microlensing observations is the addition of high-precision astrometry, allowing detection of the astrometric shift of the source during the event. Combined with the lens parallax, provided by the HST event light curve, the astrometric shift provides a direct measurement of the lens mass. We will detect 120 microlensing events, of which 45% will show astrometric deflections, leading to direct determinations of the lens masses. Of these, about 18 lenses are expected to be BHs and 14 of them NSs, along with about 22 events due to main-sequence stars.To date, BH and NS masses have been directly measured only in binaries; no isolated BH has been detected unambiguously within our Galaxy. A survey of the scope proposed here is the only means available at present for measuring the mass function of isolated BHs and NSs, and moreover one that is normalized to that of luminous stars. The results will provide a quantitative estimate of the mass content in the form of stellar remnants in the young Galactic disk and old bulge, and important constraints on SN/GRB explosion mechanisms that produce NSs and BHs.Our data will also be useful for other investigations, including a more accurate determination of the microlensing optical depth, faint variable stars, bulge proper motions and kinematics, and a deep luminosity function of the disk and bulge stars.

  10. Gravitational lens system SDSS J1339+1310: microlensing factory and time delay

    Science.gov (United States)

    Goicoechea, L. J.; Shalyapin, V. N.

    2016-12-01

    We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the r-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009-2016. These new data in both the wavelength and time domains have confirmed that the system is an unusual microlensing factory. The C iv emission line is remarkably microlensed, since the microlensing magnification of B relative to that for A, μBA, reaches a value of 1.4 ( 0.4 mag) for its core. Moreover, the B image shows a red wing enhancement of C iv flux (relative to A), and μBA = 2 (0.75 mag) for the C iv broad-line emission. Regarding the nuclear continuum, we find a chromatic behaviour of μBA, which roughly varies from 5 (1.75 mag) at 7000 Å to 6 (1.95 mag) at 4000 Å. We also detect significant microlensing variability in the r band, and this includes a number of microlensing events on timescales of 50-100 d. Fortunately, the presence of an intrinsic 0.7 mag dip in the light curves of A and B, permitted us to measure the time delay between both quasar images. This delay is ΔtAB = 47 d (1σ confidence interval; A is leading), in good agreement with predictions of lens models. Tables 1-3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A77

  11. Stellar, Remnant, Planetary, and Dark-Object Masses from Astrometric Microlensing

    Science.gov (United States)

    Gould, Andrew P.; Bennett, David P.; Boden, Andrew; Depoy, Darren L.; Gaudi, Scott B.; Griest, Kim; Han, Cheongho; Paczynski, Bohdan; Reid, I. Neill

    2004-01-01

    The primary goal of our project is to make a complete census of the stellar population of the Galaxy. We are broadening the term stellar here to include both ordinary stars and dark stars. Ordinary stars, burning their nuclear fuel and shining, can perhaps best be studied with traditional astronomical techniques, but dark stars, by which we include old brown dwarfs, black holes, old white dwarfs, neutron stars, and perhaps exotic objects such as mirror matter stars or primordial black holes, can only be studied by their gravitational effects. Traditionally, these objects have been probed in binaries, and thus selected in a way that may or may not be representative of their respective field populations. The only way to examine the field population of these stars is through microlensing, the deflection of light from a visible star in the background by an object (dark or not) in the foreground. When lensed, there are two images of the background star. Although these images cannot be resolved when the lens has a stellar mass, the lensing effect can be detected in two ways: photometrically, i.e. by measuring the magnification of the source by the lens, and astrometrically, i.e. by measuring the shift in the centroid of the two images. Photometric microlensing experiments have detected hundreds of microlensing events over the past decade. Despite its successes, photometric microlensing has so far been somewhat frustrating because these events are difficult to interpret. Almost nothing is known about the masses of individual lenses and very little is known about the statistical properties of the lenses treated as a whole, such as their average mass. Although probably over 100 of the lenses are in fact dark objects, we can't determine which they are, let alone investigate finer details such as what their masses are, and where they are in the Galaxy. With SIM, we will break the microlensing degeneracy, and allow detailed interpretation of individual microlensing events. We

  12. Black Holes, Neutron Stars and White Dwarf Candidates from Microlensing with OGLE-III

    CERN Document Server

    Wyrzykowski, L; Skowron, J; Rybicki, K A; Mroz, P; Kozlowski, S; Udalski, A; Szymanski, M K; Pietrzynski, G; Soszynski, I; Ulaczyk, K; Pietrukowicz, P; Poleski, R; Pawlak, M; Ilkiewicz, K; Rattenbury, N J

    2015-01-01

    Most stellar remnants so far have been found in binary systems, where they interact with matter from their companions. Isolated neutron stars and black holes are difficult to find as they are dark, yet they are predicted to exist in our Galaxy in vast numbers. We explored the OGLE-III database of 150 million objects observed in years 2001-2009 and found 59 microlensing events exhibiting a parallax effect due to the Earth's motion around the Sun. Combining parallax and brightness measurements from microlensing light curves with expected proper motions in the Milky Way, we identified 15 microlensing events which are consistent with having a white dwarf, neutron star or a black hole lens and we estimated their masses and distances. The most massive of our black hole candidates has 8.3 M_Sun and is at a distance of 2.4 kpc. The distribution of masses of our candidates indicates a continuum in mass distribution with no mass gap between neutron stars and black holes. We also present predictions on how such events w...

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

    CERN Document Server

    Bachelet, E; Han, C; Fouqué, P; Gould, A; Menzies, J W; Beaulieu, J -P; Bennett, D P; Bond, I A; Dong, Subo; Heyrovský, D; Marquette, J B; Marshall, J; Skowron, J; Street, R A; Sumi, T; Udalski, A; Abe, L; Agabi, K; Albrow, M D; Allen, W; Bertin, E; Bos, M; Bramich, D M; Chavez, J; Christie, G W; Cole, A A; Crouzet, N; Dieters, S; Dominik, M; Drummond, J; Greenhill, J; Guillot, T; Henderson, C B; Hessman, F V; Horne, K; Hundertmark, M; Johnson, J A; Jørgensen, U G; Kandori, R; Liebig, C; Mékarnia, D; McCormick, J; Moorhouse, D; Nagayama, T; Nataf, D; Natusch, T; Nishiyama, S; Rivet, J -P; Sahu, K C; Shvartzvald, Y; Thornley, G; Tomczak, A R; Tsapras, Y; Yee, J C; Batista, V; Bennett, C S; Brillant, S; Caldwell, J A R; Cassan, A; Corrales, E; Coutures, C; Prester, D Dominis; Donatowicz, J; Kubas, D; Martin, R; Williams, A; Zub, M; de Almeida, L Andrade; DePoy, D L; Gaudi, B S; Hung, L -W; Jablonski, F; Kaspi, S; Klein, N; Lee, C -U; Lee, Y; Koo, J -R; Maoz, D; Muñoz, J A; Pogge, R W; Polishook, D; Shporer, A; Abe, F; Botzler, C S; Chote, P; Freeman, M; Fukui, A; Furusawa, K; Harris, P; Itow, Y; Kobara, S; Ling, C H; Masuda, K; Matsubara, Y; Miyake, N; Ohmori, K; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Suzuki, D; Sweatman, W L; Tristram, P J; Wada, K; Yock, P C M; Szymański, M K; Soszyński, I; Kubiak, M; Poleski, R; Ulaczyk, K; Pietrzyński, G; Wyrzykowski, Ł; Kains, N; Snodgrass, C; Steele, I A; Alsubai, K A; Bozza, V; Browne, P; Burgdorf, M J; Novati, S Calchi; Dodds, P; Dreizler, S; Finet, F; Gerner, T; Hardis, S; Harpsøe, K; Hinse, T C; Kerins, E; Mancini, L; Mathiasen, M; Penny, M T; Proft, S; Rahvar, S; Ricci, D; Scarpetta, G; Schäfer, S; Schönebeck, F; Southworth, J; Surdej, J; Wambsganss, J

    2012-01-01

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

  14. Gravitational microlensing of gamma-ray blazars

    DEFF Research Database (Denmark)

    F. Torres, Diego; E. Romero, Gustavo; F. Eiroa, Ernesto;

    2003-01-01

    We present a detailed study of the effects of gravitational microlensing on compact and distant $\\gamma$-ray blazars. These objects have $\\gamma$-ray emitting regions which are small enough as to be affected by microlensing effects produced by stars lying in intermediate galaxies. We analyze...... the temporal evolution of the gamma-ray magnification for sources moving in a caustic pattern field, where the combined effects of thousands of stars are taken into account using a numerical technique. We propose that some of the unidentified $\\gamma$-ray sources (particularly some of those lying at high...... galactic latitude whose gamma-ray statistical properties are very similar to detected $\\gamma$-ray blazars) are indeed the result of gravitational lensing magnification of background undetected Active Galactic Nuclei (AGNs)....

  15. Microlensing Signature of Binary Black Holes

    Science.gov (United States)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  16. Constraints from microlensing on the COBE bar

    Science.gov (United States)

    Zhao, H. S.

    Since the first review of converging evidences for a bar in the center of the Galaxy by de Zeeuw (1992) at the IAU Sym. 153 in Gent five years ago, the Galactic bar idea has been put on a solid footing by an influx of new data (COBE/DIRBE maps, star count data of bulge red clump giants, microlensing optical depth, and bulge stellar proper motions, etc.) and a burst of increasingly sophisticated theoretical models (triaxial luminosity models of Dwek et al. 1994, and Binney, Gerhard & Spergel 1997, steady state stellar bar dynamical model of Zhao 1996, combined luminosity, microlensing and gas kinematics models of Zhao, Rich & Spergel 1996, and Bissantz et al. 1997, etc.), which fit new data and improve upon earlier simple bulge/bar models (Kent 1992, Binney et al. 1991, Blitz & Spergel 1991). While research in this field shifts more and more to constraining the exact phase space and parameter space of the bar, both the non-uniqueness of and the mismatches among bars from different datasets start to show up. I compare the bar from microlensing data with the COBE bar and point out the effects the non-uniqueness.

  17. Detectability of extrasolar moons as gravitational microlenses

    CERN Document Server

    Liebig, Christine

    2009-01-01

    We evaluate gravitational lensing as a technique for the detection of extrasolar moons. Since 2004 gravitational microlensing has been successfully applied as a detection method for extrasolar planets. In principle, the method is sensitive to masses as low as an Earth mass or even a fraction of it. Hence it seems natural to investigate the microlensing effects of moons around extrasolar planets. We explore the simplest conceivable triple lens system, containing one star, one planet and one moon. From a microlensing point of view, this system can be modelled as a particular triple with hierarchical mass ratios very different from unity. Since the moon orbits the planet, the planet-moon separation will be small compared to the distance between planet and star. Such a configuration can lead to a complex interference of caustics. We present detectability and detection limits by comparing triple-lens light curves to best-fit binary light curves as caused by a double-lens system consisting of host star and planet -...

  18. Liquid Crystal Microlenses for Autostereoscopic Displays

    Directory of Open Access Journals (Sweden)

    José Francisco Algorri

    2016-01-01

    Full Text Available Three-dimensional vision has acquired great importance in the audiovisual industry in the past ten years. Despite this, the first generation of autostereoscopic displays failed to generate enough consumer excitement. Some reasons are little 3D content and performance issues. For this reason, an exponential increase in three-dimensional vision research has occurred in the last few years. In this review, a study of the historical impact of the most important technologies has been performed. This study is carried out in terms of research manuscripts per year. The results reveal that research on spatial multiplexing technique is increasing considerably and today is the most studied. For this reason, the state of the art of this technique is presented. The use of microlenses seems to be the most successful method to obtain autostereoscopic vision. When they are fabricated with liquid crystal materials, extended capabilities are produced. Among the numerous techniques for manufacturing liquid crystal microlenses, this review covers the most viable designs for its use in autostereoscopic displays. For this reason, some of the most important topologies and their relation with autostereoscopic displays are presented. Finally, the challenges in some recent applications, such as portable devices, and the future of three-dimensional displays based on liquid crystal microlenses are outlined.

  19. Extending the Planetary Mass Function to Earth Mass by Microlensing at Moderately High Magnification

    CERN Document Server

    Abe, Fumio; Barnard, Ellen; Baudrey, Julie; Botzler, Christine; Douchin, Dimitri; Freeman, Matthew; Larsen, Patricia; Niemiec, Anna; Perrott, Yvette; Philpott, Lydia; Rattenbury, Nicholas; Yock, Philip

    2013-01-01

    A measurement by microlensing of the planetary mass function of planets with masses ranging from 5M_E to 10M_J and orbital radii from 0.5 to 10 AU was reported recently. A strategy for extending the mass range down to (1-3)M_E is proposed here. This entails monitoring the peaks of a few tens of microlensing events with moderately high magnifications with 1-2m class telescopes. Planets of a few Earth masses are found to produce deviations of ~ 5% to the peaks of microlensing light curves with durations ~ (0.7-3)hr in events with magnification ~ 100 if the projected separation of the planet lies in the annular region (0.85-1.2)r_E. Similar deviations are produced by Earth mass planets in the annular region (0.95-1.05)r_E. It is possible that sub-Earths could be detected very close to the Einstein ring if they are sufficiently abundant, and also planetary systems with more than one low mass planet.

  20. Predictions on the detection of the free-floating planet population with K2 and spitzer microlensing campaigns

    Science.gov (United States)

    Hamolli, L.; De Paolis, F.; Hafizi, M.; Nucita, A. A.

    2017-01-01

    The K2's Campaign 9 (K2C9) by the Kepler satellite for microlensing observations towards the Galactic bulge started on April 7, 2016, and is going to last for about three months. It offers the first chance to measure the masses of members of the large population of the isolated dark low-mass objects further away in our Galaxy, free-floating planets (FFPs). Intentionally, this observational period of K2 will overlap with that of the 2016 Spitzer follow-up microlensing project expected to start in June, 2016. Therefore, for the first time it is going to be possible to observe simultaneously the same microlensing events from a ground-based telescope and two satellites. This will help in removing the two-fold degeneracy of the impact parameter and in estimating the FFP mass, provided that the angular Einstein ring radius ΘE is measured. In this paper we calculate the probability that a microlensing event is detectable by two or more telescopes and study how it depends on the mass function index of FFPs and the position of the observers on the orbit.

  1. Microlensing by stars in the disk of M31

    CERN Document Server

    Gould, A

    1994-01-01

    The optical depth to microlensing toward M31 due to known stars in the disk of M31 itself is \\tau\\sim 2\\times 10^{-7}e^{-r/d} where d is the disk scale length and r is the distance along the major axis. Thus, there can be significant lensing toward the M31 disk even if M31 contains no dark compact objects. The optical depth has a strong dependence on azimuthal angle: at fixed radius \\tau\\propto[1+ (h/d)\\tan i\\cos\\phi]^{-2} where h is the scale height of the disk, i=75^\\circ is the inclination of M31, and \\phi is the azimuthal angle relative to the near minor axis. By measuring the optical depth as a function of radial and azimuthal position, it is possible to estimate h and d for the mass of the M31 disk, and so determine whether the disk light traces disk mass. Ground-based observations in 0.\\hskip-2pt''5 seeing of 0.8 \\rm deg^2 once per week could yield \\sim 3 events per year. With an ambitious space-based project, it would be possible to to observe \\sim 80 events per year. If lensing events were dominated ...

  2. Optimal Survey Strategies and Predicted Planet Yields for the Korean Microlensing Telescope Network

    CERN Document Server

    Henderson, Calen B; Han, Cheongho; Skowron, Jan; Penny, Matthew T; Nataf, David; Gould, Andrew P

    2014-01-01

    The Korean Microlensing Telescope Network (KMTNet) will consist of three 1.6m telescopes each with a 4 deg^{2} field of view (FoV) and will be dedicated to monitoring the Galactic Bulge to detect exoplanets via gravitational microlensing. KMTNet's combination of aperture size, FoV, cadence, and longitudinal coverage will provide a unique opportunity to probe exoplanet demographics in an unbiased way. Here we present simulations that optimize the observing strategy for, and predict the planetary yields of, KMTNet. We find preferences for four target fields located in the central Bulge and an exposure time of t_{exp} = 120s, leading to the detection of ~2,200 microlensing events per year. We estimate the planet detection rates for planets with mass and separation across the ranges 0.1 <= M_{p}/M_{Earth} <= 1000 and 0.4 <= a/AU <= 16, respectively. Normalizing these rates to the cool-planet mass function of Cassan (2012), we predict KMTNet will be approximately uniformly sensitive to planets with mas...

  3. Exoplanetary searches with gravitational microlensing: polarization issues

    CERN Document Server

    Zakharov, A F; De Paolis, F; Nucita, A A; Strafella, F; Novati, S Calchi; Jetzer, Ph

    2013-01-01

    There are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potentiality of detecting Earth-like planets at distances about a few astronomical units from their host star or near the so-called snow line with a temperature in the range $0-100^0$ C on a solid surface of an exoplanet. We emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source.

  4. Cosmic String Detection via Microlensing of Stars

    CERN Document Server

    Chernoff, David F

    2007-01-01

    Cosmic superstrings are produced towards the end of the brane inflation. If the string tension is low enough, loops tend to be relatively long-lived. The resultant string network is expected to contain many loops which are smaller than typical Galactic scales. Cosmic expansion damps the center of mass motion of the loops which then cluster like cold dark matter. Loops will lens stars within the galaxy and local group. We explore microlensing of stars as a tool to detect and to characterize some of the fundamental string and string network properties, including the dimensionless string tension $G \\mu/c^2$ and the density of string loops within the Galaxy. As $G \\mu \\to 0$ the intrinsic microlensing rate diverges as $1/\\sqrt{G \\mu}$ but experimental detection will be limited by shortness of the lensing timescale and/or smallness of the bending angle which each vary $\\propto G \\mu$. We find that detection is feasible for a range of tensions. As an illustration, the planned optical astrometric survey mission, Gai...

  5. Quantitative Interpretation of Quasar Microlensing Light Curves

    CERN Document Server

    Kochanek, C S

    2004-01-01

    We develop a general method for analyzing the light curves of microlensed quasars and apply it to the OGLE light curves of the four-image lens Q2237+0305. We simultaneously estimate the effective source velocity, the average stellar mass, the stellar mass function, and the size and structure of the quasar accretion disk. The light curves imply an effective source plane velocity of 10200 km/s ) =0.037h^2 solar masses (0.0059h^2 /Msun < 0.20h^2). We were unable to distinguish a Salpeter mass function from one in which all stars had the same mass, but we do find a strong lower bound of 50% on the fraction of the surface mass density represented by the microlenses. Our models favor a standard thin accretion disk model as the source structure over a simple Gaussian source. For a face-on, thin disk radiating as a black body with temperature profile T_s ~ R^(-3/4), the radius r_s where the temperature matches the filter pass band (2000 Angstroms or T_s(r_s)=70000K) is (1.4 x 10^15)/h cm < r_s < (4.5 x 10^15...

  6. pyLIMA : an open source microlensing software

    Science.gov (United States)

    Bachelet, Etienne

    2017-01-01

    Planetary microlensing is a unique tool to detect cold planets around low-mass stars which is approaching a watershed in discoveries as near-future missions incorporate dedicated surveys. NASA and ESA have decided to complement WFIRST-AFTA and Euclid with microlensing programs to enrich our statistics about this planetary population. Of the nany challenges in- herent in these missions, the data analysis is of primary importance, yet is often perceived as time consuming, complex and daunting barrier to participation in the field. We present the first open source modeling software to conduct a microlensing analysis. This software is written in Python and use as much as possible existing packages.

  7. The MACHO project 2nd year LMC microlensing results and dark matter implications

    CERN Document Server

    Pratt, M R; Allsman, R A; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Cook, K H; Freeman, K C; Griest, K; Guern, J A; Lehner, M J; Marshall, S L; Peterson, B A; Quinn, P J; Rodgers, A W; Stubbs, C W; Sutherland, W; Welch, D L

    1996-01-01

    The MACHO Project is searching for galactic dark matter in the form of massive compact halo objects (Machos). Millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge are photometrically monitored in an attempt to detect rare gravitational microlensing events caused by otherwise invisible Machos. Analysis of two years of photometry on 8.5 million stars in the LMC reveals 8 candidate microlensing events, far more than the \\sim1 event expected from lensing by low-mass stars in known galactic populations. From these eight events we estimate the optical depth towards the LMC from events with 2 < \\that < 200 days to be \\tau_2^{200} \\approx 2.9 ^{+1.4}_{-0.9} \\ten{-7}. This exceeds the optical depth of 0.5\\ten{-7} expected from known stars and is to be compared with an optical depth of 4.7\\ten{-7} predicted for a ``standard'' halo composed entirely of Machos. The total mass in this lensing population is \\approx 2^{+1.2}_{-0.7} \\ten{11} \\msun (within 50 kpc from t...

  8. Detecting extrasolar asteroid belts through their microlensing signatures

    Science.gov (United States)

    Lake, Ethan; Zheng, Zheng; Dong, Subo

    2017-02-01

    We propose that extrasolar asteroid belts can be detected through their gravitational microlensing signatures. Asteroid belt + star lens systems create so-called 'pseudo-caustics', regions in the source plane where the magnification exhibits a finite but discontinuous jump. These features allow such systems to generate distinctive signatures in the microlensing light curves for a wide range of belt configurations, with source trajectories as far as tenths of the Einstein ring radius from the centre of the lens. Sample light curves for a range of asteroid belt parameters are presented. In the near future, space-based microlensing surveys like WFIRST, which will have the power of detecting per cent-level changes in microlensing light curves even with subminute exposure times, may be able to discover extrasolar asteroid belts with masses of the order of an earth mass.

  9. Extrasolar planets detections and statistics through gravitational microlensing

    Science.gov (United States)

    Cassan, A.

    2014-10-01

    Gravitational microlensing was proposed thirty years ago as a promising method to probe the existence and properties of compact objects in the Galaxy and its surroundings. The particularity and strength of the technique is based on the fact that the detection does not rely on the detection of the photon emission of the object itself, but on the way its mass affects the path of light of a background, almost aligned source. Detections thus include not only bright, but also dark objects. Today, the many successes of gravitational microlensing have largely exceeded the original promises. Microlensing contributed important results and breakthroughs in several astrophysical fields as it was used as a powerful tool to probe the Galactic structure (proper motions, extinction maps), to search for dark and compact massive objects in the halo and disk of the Milky Way, to probe the atmospheres of bulge red giant stars, to search for low-mass stars and brown dwarfs and to hunt for extrasolar planets. As an extrasolar planet detection method, microlensing nowadays stands in the top five of the successful observational techniques. Compared to other (complementary) detection methods, microlensing provides unique information on the population of exoplanets, because it allows the detection of very low-mass planets (down to the mass of the Earth) at large orbital distances from their star (0.5 to 10 AU). It is also the only technique that allows the discovery of planets at distances from Earth greater than a few kiloparsecs, up to the bulge of the Galaxy. Microlensing discoveries include the first ever detection of a cool super-Earth around an M-dwarf star, the detection of several cool Neptunes, Jupiters and super-Jupiters, as well as multi-planetary systems and brown dwarfs. So far, the least massive planet detected by microlensing has only three times the mass of the Earth and orbits a very low mass star at the edge of the brown dwarf regime. Several free-floating planetary

  10. Application of Compressive Sensing to Gravitational Microlensing Experiments

    Science.gov (United States)

    Korde-Patel, Asmita; Barry, Richard K.; Mohsenin, Tinoosh

    2016-01-01

    Compressive Sensing is an emerging technology for data compression and simultaneous data acquisition. This is an enabling technique for significant reduction in data bandwidth, and transmission power and hence, can greatly benefit spaceflight instruments. We apply this process to detect exoplanets via gravitational microlensing. We experiment with various impact parameters that describe microlensing curves to determine the effectiveness and uncertainty caused by Compressive Sensing. Finally, we describe implications for spaceflight missions.

  11. Could the Optical Transient SCP 06F6 be due to Microlensing?

    Indian Academy of Sciences (India)

    Marek Biesiada

    2010-12-01

    In this paper, we consider the mysterious optical transient SCP 06F6 displaying a symmetric light curve with a (half-time) duration of about 100 days. The projected location of the event falls close to the center of the galaxy cluster CL 1432.5 + 332.8 lying at the redshift = 1.112. Guided by suggestive symmetry of the light curve and its similarity in two photometric bands, which is a typical signature of microlensing events, we discuss this possibility in several scenarios. As a consistency check we use the lens mass inferred from the event duration and the size of the source. The second check comes from a plausible assumption that since the event was highly magnified there was a perfect alignment at the maximum magnification. A scenario where the lens and the source are located in our Galaxy is ruled out. There remain extragalactic scenarios in which the source is a broad absorption line quasar at redshift 2.7 (as might be suggested by transient’s spectroscopy) and the lens could be a compact object associated either with the cluster or with quasar’s host galaxy. They give reasonable results. Even if the true nature of the transient eventually turns out different, the idea presented here is interesting from the perspective of cosmological microlensing studies.

  12. Chromatic control in coextruded layered polymer microlenses

    CERN Document Server

    Crescimanno, Michael; Andrews, James H; Zhou, Chuanhong; Petrus, Joshua B; Merlo, Cory; Bagheri, Cameron; Hetzel, Connor; Tancabel, James; Singer, Kenneth D; Baer, Eric

    2015-01-01

    We describe the formation, characterization and theoretical understanding of microlenses comprised of alternating polystyrene and polymethylmethacrylate layers produced by multilayer coextrusion. These lenses are fabricated by photolithography, using a grayscale mask followed by plasma etching, so that the refractive index alternation of the bilayer stack appears across the radius of the microlens. The alternating quarter-wave thick layers form a one-dimensional photonic crystal whose dispersion augments the material dispersion, allowing one to sculpt the chromatic dispersion of the lens by adjusting the layered structure. Using Huygen's principle, we model our experimental measurements of the focal length of these lenses across the reflection band of the multilayer polymer film from which the microlens is fashioned. For a 56 micron diameter multilayered lens of focal length 300 microns, we measured a nearly 25 percent variation in the focal length across a shallow, 50 nm-wide reflection band.

  13. Observation of Microlensing towards the Galactic Spiral Arms EROS II 3 year survey

    CERN Document Server

    Derue, F; Albert, J N; Andersen, J; Ansari, R; Aubourg, E; Bareyre, P; Bauer2, F; Beaulieu, J P; Blanc, G; Bouquet, A; Char, S; Charlot, X; Couchot, F; Couture, C; Ferlet, R; Glicenstein, J F; Goldman, B; Gould, A; Gros, M; Hassinski, J; Hamilton, J C; Hardin, D; deKat, J; Kim, A; Lassere, T; Lesquoy, E; Loup, C; Magneville, C; Mansoux, B; Marquette, J B; Gra, D; Maurice, E; Milsztajn, A; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Prévôt, L; Regnault, N; Rich, J; Spiro, M; Vidal-madjar, A; Vigroux, L; Zylberajch, S

    2000-01-01

    We present an analysis of the light curves of 9.1 million stars observed during three seasons by EROS (Experience de Recherche d'Objets Sombres), in the Galactic plane away from the bulge. Seven stars exhibit luminosity variations compatible with gravitational microlensing effects due to unseen objects. The corresponding optical depth, averaged over four directions, is tau = 0.45 +0.24 -0.11 x 10^-6. While this value is compatible with expectations from simple galactic models under reasonable assumptions on the target distances, we find an excess of events with short timescale towards the direction closest to the Galactic Centre.

  14. VVV Survey Observations of a Microlensing Stellar Mass Black Hole Candidate in the Field of the Globular Cluster NGC 6553

    CERN Document Server

    Minniti, D; Alonso-Garcia, J; Anguita, T; Catelan, M; Gran, F; Motta, V; Muro, G; Rojas, K; Saito, R K

    2015-01-01

    We report the discovery of a large timescale candidate microlensing event of a bulge stellar source based on near-infrared observations with the VISTA Variables in the Via Lactea Survey (VVV). The new microlensing event is projected only 3.5 arcmin away from the center of the globular cluster NGC 6553. The source appears to be a bulge giant star with magnitude Ks = 13.52, based on the position in the color-magnitude diagram. The foreground lens may be located in the globular cluster, which has well-known parameters such as distance and proper motions. If the lens is a cluster member, we can directly estimate its mass simply following Paczynski et al. (1996) which is a modified version of the more general case due to Refsdal. In that case, the lens would be a massive stellar remnant, with M = 1.5-3.5 Msun. If the blending fraction of the microlensing event appears to be small, and this lens would represent a good isolated black hole (BH) candidate, that would be the oldest BH known. Alternative explanations (w...

  15. Constraining the Frequency of Free-Floating Planets from a Synthesis of Microlensing, Radial Velocity, and Direct Imaging Survey Results

    CERN Document Server

    Clanton, Christian

    2016-01-01

    A microlensing survey by Sumi et al. (2011) exhibits an overabundance of short-timescale events (STEs; t_E~10 AU) and free-floating planets. Assuming these STEs are indeed due to planetary-mass objects, we aim to constrain the fraction of these events that can be explained by bound but wide-separation planets. We fit the observed timescale distribution with a lens mass function comprised of brown dwarfs, main-sequence stars, and stellar remnants, finding and thus corroborating the initial identification of an excess of STEs. We then include a population of bound planets that are expected not to show signatures of the primary lens (host) in their microlensing light curves and that are also consistent with results from representative microlensing, radial velocity, and direct imaging surveys. We find that bound planets alone cannot explain the entire STE excess without violating the constraints from the surveys we consider and thus some fraction of these events must be due to free-floating planets, if our model ...

  16. Reevaluating the feasibility of ground-based Earth-mass microlensing planet detections

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Youn Kil; Park, Hyuk; Han, Cheongho; Hwang, Kyu-Ha; Shin, In-Gu; Choi, Joon-Young, E-mail: cheongho@astroph.chungbuk.ac.kr [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of)

    2014-05-10

    An important strength of the microlensing method to detect extrasolar planets is its high sensitivity to low-mass planets. However, many believe that microlensing detections of Earth-mass planets from ground-based observation would be difficult because of limits set by finite-source effects. This view comes from the previous estimation of planet detection probability based on the fractional deviation of planetary signals; however, a proper probability estimation is required when considering the source brightness, which is directly related to the photometric precision. In this paper, we reevaluate the feasibility of low-mass planet detections by considering photometric precision for different populations of source stars. From this, we find that the contribution of improved photometric precision to the planetary signal of a giant-source event is large enough to compensate for the decrease in magnification excess caused by finite-source effects. As a result, we conclude that giant-source events are suitable targets for Earth-mass planet detections with significantly higher detection probability than events involved with source stars of smaller radii, and we predict that Earth-mass planets could be detected by prospective high-cadence surveys.

  17. MOA 2011-BLG-028Lb: a Neptune-mass Microlensing Planet in the Galactic Bulge

    CERN Document Server

    Skowron, J; Poleski, R; Kozłowski, S; Szymański, M K; Wyrzykowski, Ł; Ulaczyk, K; Pietrukowicz, P; Pietrzyński, G; Soszyński, I; Abe, F; Bennett, D P; Bhattacharya, A; Bond, I A; Freeman, M; Fukui, A; Hirao, Y; Itow, Y; Koshimoto, N; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Nagakane, M; Ohnishi, K; Rattenbury, N; Saito, To; Sullivan, D J; Sumi, T; Suzuki, D; Tristram, P J; Yonehara, A; Dominik, M; Jørgensen, U G; Bozza, V; Harpsøe, K; Hundertmark, M; Skottfelt, J

    2015-01-01

    We present the discovery of a Neptune-mass planet orbiting a 0.8 +- 0.3 M_Sun star in the Galactic bulge. The planet manifested itself during the microlensing event MOA 2011-BLG-028/OGLE-2011-BLG-0203 as a low-mass companion to the lens star. The analysis of the light curve provides the measurement of the mass ratio: (1.2 +- 0.2) x 10^-4, which indicates the mass of the planet to be 12-60 Earth masses. The lensing system is located at 7.3 +- 0.7 kpc away from the Earth near the direction to Baade's Window. The projected separation of the planet, at the time of the microlensing event, was 3.1-5.2 AU. Although the "microlens parallax" effect is not detected in the light curve of this event, preventing the actual mass measurement, the uncertainties of mass and distance estimation are narrowed by the measurement of the source star proper motion on the OGLE-III images spanning eight years, and by the low amount of blended light seen, proving that the host star cannot be too bright and massive. We also discuss the ...

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

    CERN Document Server

    Poleski, Radosław; Christie, Grant W; Udalski, Andrzej; Gould, Andrew; Bachelet, Etienne; Skottfelt, Jesper; Novati, Sebastiano Calchi; Szymański, M K; Soszyński, I; Pietrzyński, G; Wyrzykowski, Ł; Ulaczyk, K; Pietrukowicz, P; Kozłowski, Szymon; Skowron, J; Mróz, P; Pawlak, M; Beichman, C; Bryden, G; Carey, S; Fausnaugh, M; Gaudi, B S; Henderson, C B; Pogge, R W; Shvartzvald, Y; Wibking, B; Yee, J C; Beatty, T G; Eastman, J D; Drummond, J; Friedmann, M; Henderson, M; Johnson, J A; Kaspi, S; Maoz, D; McCormick, J; McCrady, N; Natusch, T; Ngan, H; Porritt, I; Relles, H M; Sliski, D H; Tan, T -G; Wittenmyer, R A; Wright, J T; Street, R A; Tsapras, Y; Bramich, D M; Horne, K; Snodgrass, C; Steele, I A; Menzies, J; Jaimes, R Figuera; Wambsganss, J; Schmidt, R; Cassan, A; Ranc, C; Mao, S; Bozza, V; Dominik, M; Hundertmark, M P G; Jørgensen, U G; Andersen, M I; Burgdorf, M J; Ciceri, S; D'Ago, G; Evans, D F; Gu, S -H; Hinse, T C; Kains, N; Kerins, E; Korhonen, H; Kuffmeier, M; Mancini, L; Popovas, A; Rabus, M; Rahvar, S; Rasmussen, R T; Southworth, G Scarpetta J; Surdej, J; Unda-Sanzana, E; Verma, P; von Essen, C; Wang, Y -B; Wertz, O

    2015-01-01

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

  19. MACHO Alert 95-30 First Real-Time Observation of Extended Source Effects in Gravitational Microlensing

    CERN Document Server

    Alcock, C B; Allsman, R A; Alves, D R; Axelrod, T S; Banks, T; Beaulieu, S F; Becker, A C; Becker, R H; Bennett, D P; Bond, I A; Carter, B S; Cook, K H; Dodd, R J; Freeman, K C; Gregg, M D; Griest, K; Hearnshaw, J B; Heller, A; Honda, M; Juga Ku Jun; Kabe, S; Kaspi, S; Kilmartin, P M; Kitamura, A; Kovo, O; Lehner, M J; Love, T E; Maoz, D; Marshall, S L; Matsubara, Y; Minniti, D; Miyamoto, M; Muraki, Y; Nakamura, T; Peterson, B A; Pratt, M R; Quinn, P J; Reid, I N; Reid, M; Reiss, D; Retter, A; Rodgers, A W; Sargent, W L W; Sato, H; Sekiguchi, M; Stetson, P B; Stubbs, C W; Sullivan, D J; Sutherland, W; Tomaney, A B; Vandehei, T; Watase, Y; Welch, D L; Yanagisawa, T; Yoshizawa, M; Yock, P C M

    1997-01-01

    We present analysis of MACHO Alert 95-30, a dramatic gravitational microlensing event towards the Galactic bulge whose peak magnification departs significantly from the standard point-source microlensing model. Alert 95-30 was observed in real-time by the Global Microlensing Alert Network (GMAN), which obtained densely sampled photometric and spectroscopic data throughout the event. We interpret the light-curve ``fine structure'' as indicating transit of the lens across the extended face of the source star. This signifies resolution of a star several kpc distant. We find a lens angular impact parameter theta_{min}/theta_{source} = 0.715 +/- 0.003. This information, along with the radius and distance of the source, provides an additional constraint on the lensing system. Spectroscopic and photometric data indicate the source is an M4 III star of radius 61 +/- 12 Rsun, located on the far side of the bulge at 9 kpc. We derive a lens angular velocity, relative to the source, of 21.5 +/- 4.9 km/s/kpc, where the er...

  20. Preparing for the WFIRST Microlensing Survey: Simulations, Requirements, Survey Strategies, and Precursor Observations

    Science.gov (United States)

    Gaudi, Bernard

    As one of the four primary investigations of the Wide Field Infrared Survey Telescope (WFIRST) mission, the microlensing survey will monitor several square degrees of the Galactic bulge for a total of roughly one year. Its primary science goal is to "Complete the statistical census of planetary systems in the Galaxy, from the outer habitable zone to free floating planets, including analogs of all of the planets in our Solar System with the mass of Mars or greater.'' WFIRST will therefore (a) measure the mass function of cold bound planets with masses greater than that of roughly twice the mass of the moon, including providing an estimate of the frequency of sub-Mars-mass embryos, (b) determine the frequency of free-floating planets with masses down to the Earth and below, (c) inform the frequency and habitability of potentially habitable worlds, and (d) revolutionize our understanding of the demographics of cold planets with its exquisite sensitivity to, and large expected yield of, planets in a broad and unexplored region of parameter space. In order for the microlensing survey to be successful, we must develop a plan to go from actual survey observations obtained by the WFIRST telescope and hardware to the final science products. This plan will involve many steps, the development of software, data reduction, and analysis tools at each step, and a list of requirements for each of these components. The overarching goal of this proposal is thus to develop a complete flowdown from the science goals of the microlensing survey to the mission design and hardware components. We have assembled a team of scientists with the breadth of expertise to achieve this primary goal. Our specific subgoals are as follows. Goal 1: We will refine the input Galactic models in order to provide improved microlensing event rates in the WFIRST fields. Goal 2: We will use the improved event rate estimates, along with improvements in our simulation methodology, to provide higher

  1. Microlensing of the broad line region in 17 lensed quasars

    CERN Document Server

    Sluse, D; Courbin, F; Meylan, G; Wambsganss, J

    2012-01-01

    When an image of a strongly lensed quasar is microlensed, the different components of its spectrum are expected to be differentially magnified owing to the different sizes of the corresponding emitting region. Chromatic changes are expected to be observed in the continuum while the emission lines should be deformed as a function of the size, geometry and kinematics of the regions from which they originate. Microlensing of the emission lines has been reported only in a handful of systems so far. In this paper we search for microlensing deformations of the optical spectra of pairs of images in 17 lensed quasars. This sample is composed of 13 pairs of previously unpublished spectra and four pairs of spectra from literature. Our analysis is based on a spectral decomposition technique which allows us to isolate the microlensed fraction of the flux independently of a detailed modeling of the quasar emission lines. Using this technique, we detect microlensing of the continuum in 85% of the systems. Among them, 80% s...

  2. OGLE-2011-BLG-0265Lb: a Jovian Microlensing Planet Orbiting an M Dwarf

    CERN Document Server

    Skowron, J; Udalski, A; Han, C; Sumi, T; Shvartzvald, Y; Gould, A; Dominis-Prester, D; Street, R A; Jørgensen, U G; Bennett, D P; Bozza, V; Szymański, M K; Kubiak, M; Pietrzyński, G; Soszyński, I; Poleski, R; Kozłowski, S; Pietrukowicz, P; Ulaczyk, K; Wyrzykowski, Ł; Abe, F; Bhattacharya, A; Bond, I A; Botzler, C S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Ling, C H; Koshimoto, N; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Philpott, L C; Rattenbury, N; Saito, T; Sullivan, D J; Suzuki, D; Tristram, P J; Yock, P C M; Maoz, D; Kaspi, S; Friedman, M; Almeida, L A; Batista, V; Christie, G; Choi, J -Y; DePoy, D L; Gaudi, B S; Henderson, C; Hwang, K -H; Jablonski, F; Jung, Y K; Lee, C -U; McCormick, J; Natusch, T; Ngan, H; Park, H; Pogge, R W; Yee, J; Albrow, M D; Bachelet, E; Beaulieu, J -P; Brillant, S; Caldwell, J A R; Cassan, A; Cole, A; Corrales, E; Coutures, Ch; Dieters, S; Donatowicz, J; Fouqué, P; Greenhill, J; Kains, N; Kane, S R; Kubas, D; Marquette, J -B; Martin, R; Menzies, J; Pollard, K R; Ranc, C; Sahu, K C; Wambsganss, J; Williams, A; Wouters, D; Tsapras, Y; Bramich, D M; Horne, K; Hundertmark, M; Snodgrass, C; Steele, I A; Alsubai, K A; Browne, P; Burgdorf, M J; Novati, S Calchi; Dodds, P; Dominik, M; Dreizler, S; Fang, X -S; Gu, C -H; Hardis,; Harpsøe, K; Hessman, F V; Hinse, T C; Hornstrup, A; Jessen-Hansen, J; Kerins, E; Liebig, C; Lund, M; Lundkvist, M; Mancini, L; Mathiasen, M; Penny, M T; Rahvar, S; Ricci, D; Scarpetta, G; Skottfelt, J; Southworth, J; Surdej, J; Tregloan-Reed, J; Wertz, O

    2014-01-01

    We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies of planetary formation and evolution. High-cadence temporal coverage of the planetary signal combined with extended observations throughout the event allows us to accurately model the observed light curve. The final microlensing solution remains, however, degenerate yielding two possible configurations of the planet and the host star. In the case of the preferred solution, the mass of the planet is $M_{\\rm p}$ = 1.0 $\\pm$ 0.3 $M_{\\rm J}$, and the planet is orbiting a star with a mass $M$ = 0.23 $\\pm$ 0.07 $M_\\odot$. The second possible configuration (2\\sigma away) consists of a planet with $M_{\\rm p}$ = 0.6 $\\pm$ 0.2 $M_{\\rm J}$ and host star with $M$ = 0.15 $\\pm$ 0.06 $M_{\\odot}$. The system is located in the Galactic disk 3-4 kpc towards the Galactic bulge. In...

  3. The First Circumbinary Planet Found by Microlensing: OGLE-2007-BLG-349L(AB)c

    CERN Document Server

    Bennett, D P; Udalski, A; Gould, A; Tsapras, Y; Kubas, D; Bond, I A; Greenhill, J; Cassan, A; Rattenbury, N J; Boyajian, T S; Luhn, J; Penny, M T; Anderson, J; Abe, F; Bhattacharya, A; Botzler, C S; 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; Perrott, Y C; Saito, To; Sharan, A; Sullivan, D J; Sumi, T; Suzuki, D; Tristram, P J; Yonehara, A; Yock, P C M; Szymanski, M K; Soszynski, I; Ulaczyk, K; Wyrzykowski, L; Allen, W; DePoy, D; Gal-Yam, A; Gaudi, B S; Han, C; Monard, I A G; Ofek, E; Pogge, R W; Street, R A; Bramich, D M; Dominik, M; Horne, K; Snodgrass, C; Steele, I A; Albrow, M D; Bachelet, E; Batista, V; Beaulieu, J -P; Brillant, S; Caldwell, J A R; Cole, A; Coutures, C; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouque, P; Hundertmark, M; Jorgensen, U G; Kains, N; Kane, S R; Marquette, J -B; Menzies, J; Pollard, K R; Ranc, C; Sahu, K C; Wambsganss, J; Williams, A; Zub, M

    2016-01-01

    We present the analysis of the first circumbinary planet microlensing event, OGLE-2007-BLG-349. This event has a strong planetary signal that is best fit with a mass ratio of $q \\approx 3.4\\times 10^{-4}$, but there is an additional signal due to an additional lens mass, either another planet or another star. We find acceptable light curve fits with two classes of models: 2-planet models (with a single host star) and circumbinary planet models. The light curve also reveals a significant microlensing parallax effect, which constraints the mass of the lens system to be $M_L \\approx 0.7 M_\\odot$. Hubble Space Telescope images resolve the lens and source stars from their neighbors, and indicate excess flux due to the star(s) in the lens system. This is consistent with the predicted flux from the circumbinary models, where the lens mass is shared between two stars, but there is not enough flux to be consistent with the 2-planet, 1-star models. So, only the circumbinary models are consistent with the HST data. They...

  4. OGLE-2008-BLG-513Lb: The Orbital Solution for a Microlensing Planet

    CERN Document Server

    Yee, J C; Dong, Subo; Greenhill, J; Tsapras, Y; Bond, I A; Gould, A; Kozlowski, S; Fouque, P; Albrow, M D; Han, C; Monard, L A G; McCormick, J; Williams, A; Kains, N; An, J; Dominik, M

    2011-01-01

    The dominant features of the microlensing event OGLE-2008-BLG-513 arise from a 2-body lens with a mass ratio q=0.027+/-0.001. The light curve cannot be adequately described by a static, 2-body lens model, which forces us to consider the orbital motion of the lens system. Including orbital motion improves the fit by Delta chi^2>1000. We model the orbital motion as a Keplerian orbit, and with the additional information from microlens parallax, we are able to place constraints on all eight parameters of the orbit. If our model is correct, this gives us the most complete orbital information of any microlensing planet. We find that the host star is 0.18event is also unusual because the positio...

  5. Optimal survey strategies and predicted planet yields for the Korean microlensing telescope network

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Calen B.; Gaudi, B. Scott; Skowron, Jan; Penny, Matthew T.; Gould, Andrew P. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Han, Cheongho [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Nataf, David, E-mail: henderson@astronomy.ohio-state.edu [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia)

    2014-10-10

    The Korean Microlensing Telescope Network (KMTNet) will consist of three 1.6 m telescopes each with a 4 deg{sup 2} field of view (FoV) and will be dedicated to monitoring the Galactic Bulge to detect exoplanets via gravitational microlensing. KMTNet's combination of aperture size, FoV, cadence, and longitudinal coverage will provide a unique opportunity to probe exoplanet demographics in an unbiased way. Here we present simulations that optimize the observing strategy for and predict the planetary yields of KMTNet. We find preferences for four target fields located in the central Bulge and an exposure time of t {sub exp} = 120 s, leading to the detection of ∼2200 microlensing events per year. We estimate the planet detection rates for planets with mass and separation across the ranges 0.1 ≤ M{sub p} /M {sub ⊕} ≤ 1000 and 0.4 ≤ a/AU ≤ 16, respectively. Normalizing these rates to the cool-planet mass function of Cassan et al., we predict KMTNet will be approximately uniformly sensitive to planets with mass 5 ≤ M{sub p} /M {sub ⊕} ≤ 1000 and will detect ∼20 planets per year per dex in mass across that range. For lower-mass planets with mass 0.1 ≤ M{sub p} /M {sub ⊕} < 5, we predict KMTNet will detect ∼10 planets per year. We also compute the yields KMTNet will obtain for free-floating planets (FFPs) and predict KMTNet will detect ∼1 Earth-mass FFP per year, assuming an underlying population of one such planet per star in the Galaxy. Lastly, we investigate the dependence of these detection rates on the number of observatories, the photometric precision limit, and optimistic assumptions regarding seeing, throughput, and flux measurement uncertainties.

  6. OGLE 2008--BLG--290: An accurate measurement of the limb darkening of a Galactic Bulge K Giant spatially resolved by microlensing

    CERN Document Server

    Fouque, P; Dong, S; Gould, A; Udalski, A; Albrow, M D; Batista, V; Beaulieu, J -P; Bennett, D P; Bond, I A; Bramich, D M; Novati, S Calchi; Cassan, A; Coutures, C; Dieters, S; Dominik, M; Prester, D Dominis; Greenhill, J; Horne, K; Jorgensen, U G; Kozlowski, S; Kubas, D; Lee, C -H; Marquette, J -B; Mathiasen, M; Menzies, J; Monard, L A G; Nishiyama, S; Papadakis, I; Street, R; Sumi, T; Williams, A; Yee, J C; Brillant, S; Caldwell, J A R; Cole, A; Cook, K H; Donatowicz, J; Kains, N; Kane, S R; Martin, R; Pollard, K R; Sahu, K C; Tsapras, Y; Wambsganss, J; Zub, M; DePoy, D L; Gaudi, B S; Han, C; Lee, C -U; Park, B -G; Pogge, R W; Kubiak, M; Szymanski, M K; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; Abe, F; Fukui, A; Furusawa, K; Gilmore, A C; Hearnshaw, J B; Itow, Y; ~Kamiya, K; Kilmartin, P M; Korpela, A V; Lin, W; Ling, C H; Masuda, K; Matsubara, Y; Miyake, N; Muraki, Y; Nagaya, M; Ohnishi, K; Okumura, T; Perrott, Y; Rattenbury, N J; Saito, To; Sako, T; Sato, S; Skuljan, L; Sullivan, D; Sweatman, W; Tristram, P J; Yock, P C M; Allan, A; Bode, M F; Burgdorf, M J; Clay, N; Fraser, S N; Hawkins, E; Kerins, E; Lister, T A; Mottram, C J; Saunders, E S; Snodgrass, C; Steele, I A; Wheatley, P J; Anguita, T; Bozza, V; Harpsoe, K; Hinse, T C; Hundertmark, M; Kjaergaard, P; Liebig, C; Mancini, L; Masi, G; Rahvar, S; Ricci, D; Scarpetta, G; Southworth, J; Surdej, J; Thone, C C; Riffeser, A; ~Seitz, S; Bender, R

    2015-01-01

    Gravitational microlensing is not only a successful tool for discovering distant exoplanets, but it also enables characterization of the lens and source stars involved in the lensing event. In high magnification events, the lens caustic may cross over the source disk, which allows a determination of the angular size of the source and additionally a measurement of its limb darkening. When such extended-source effects appear close to maximum magnification, the resulting light curve differs from the characteristic Paczynski point-source curve. The exact shape of the light curve close to the peak depends on the limb darkening of the source. Dense photometric coverage permits measurement of the respective limb-darkening coefficients. In the case of microlensing event OGLE 2008-BLG-290, the K giant source star reached a peak magnification of about 100. Thirteen different telescopes have covered this event in eight different photometric bands. Subsequent light-curve analysis yielded measurements of linear limb-darke...

  7. Microlensing Planet Around Brown-Dwarf

    CERN Document Server

    Han, C; Udalski, A; Sumi, T; Gaudi, B S; Gould, A; Bennett, D P; Tsapras, Y; Szymański, M K; Kubiak, M; Pietrzyński, G; Soszyński, I; Skowron, J; Kozłowski, S; Poleski, R; Ulaczyk, K; Wyrzykowski, Ł; Pietrukowicz, P; Abe, F; Bond, I A; Botzler, C S; Chote, P; Freeman, M; Fukui, A; Furusawa, K; Harris, P; Itow, Y; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Sweatman, W L; Suzuki, D; Tristram, P J; Wada, K; Yock, P C M; Batista, V; Christie, G; Choi, J -Y; DePoy, D L; Dong, Subo; Hwang, K -H; Kavka, A; Lee, C -U; Monard, L A G; Natusch, T; Ngan, H; Park, H; Pogge, R W; Porritt, I; Shin, I -G; Tan, T G; Yee, J C; Alsubai, K A; Bramich, D M; Browne, P; Dominik, M; Horne, K; Hundertmark, M; Ipatov, S; Kains, N; Liebig, C; Snodgrass, C; Steele, I A; Street, R A

    2013-01-01

    Observations of accretion disks around young brown dwarfs have led to the speculation that they may form planetary systems similar to normal stars. While there have been several detections of planetary-mass objects around brown dwarfs (2MASS 1207-3932 and 2MASS 0441-2301), these companions have relatively large mass ratios and projected separations, suggesting that they formed in a manner analogous to stellar binaries. We present the discovery of a planetary-mass object orbiting a field brown dwarf via gravitational microlensing, OGLE-2012-BLG-0358Lb. The system is a low secondary/primary mass ratio (0.080 +- 0.001), relatively tightly-separated (~0.87 AU) binary composed of a planetary-mass object with 1.9 +- 0.2 Jupiter masses orbiting a brown dwarf with a mass 0.022 M_Sun. The relatively small mass ratio and separation suggest that the companion may have formed in a protoplanetary disk around the brown dwarf host, in a manner analogous to planets.

  8. Gravitational Microlensing of Binary and Binary and Multiple Stars

    Science.gov (United States)

    Cherepashchuk, A. M.

    1995-08-01

    Recent observations of the effect of microlensing of stars of large Magellanic Clouds by dark bodies of Galactic Halo have led to the discovery of new population in our galaxy - dark bodies with amsses ~ 0.1 M(sun). As a consequence, astronomers have gained a unique possibility of using gravitational microlensing as an effective extraterestrial telescope with extremely high angular resolution. Application of this to binary stars is discussed. of particular interest is to apply microlensing to search for planetary stars . Planets and stars move about the center of gravity of the system , so the appaarent motion of a star in nonuniform and the light curve is asymetrical and colour dependent. This allows to determin basic parameters of binary system

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-11-08

    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 first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. 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 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  10. Turning AGN Microlensing From a Curiosity Into a Tool

    CERN Document Server

    Kochanek, C S; Morgan, C; Morgan, N; Poindexter, S; Chartas, G

    2006-01-01

    Microlensing of gravitationally lensed quasars by the stars in the foreground lens galaxy can be used to probe the nature of dark matter, to determine the mean stellar mass in the lens galaxy, and to measure the internal structure of quasar accretion disks. Until recently, little progress has been made toward using microlensing for these purposes because of the difficulty in obtaining the necessary data and the lack of good analysis methods. In the last few years, both problems have been solved. In particular, Bayesian analysis methods provide a general approach to measuring quantities of physical interest and their uncertainties from microlensing light curves. We discuss the data and the analysis methods and show preliminary results for all three astrophysical applications.

  11. Prospects for Characterizing Host Stars of the Planetary System Detections Predicted for the Korean Microlensing Telescope Network

    CERN Document Server

    Henderson, Calen B

    2014-01-01

    I investigate the possibility of constraining the flux of the lens (i.e., host star) for the types of planetary systems the Korean Microlensing Telescope Network is predicted to find. I examine the potential to obtain lens flux measurements by 1) imaging a lens once it is spatially resolved from the source, 2) measuring the elongation of the point spread function of the microlensing target (lens+source) when the lens and source are still unresolved, and 3) taking prompt follow-up photometry. In each case I simulate observing programs for a representative example of current ground-based adaptive optics (AO) facilities (specifically NACO on VLT), future ground-based AO facilities (GMTIFS on GMT), and future space telescopes (NIRCAM on $JWST$). Given the predicted distribution of relative lens-source proper motions, I find that the lens flux could be measured to a precision of $\\sigma_{H_{\\ell}} \\leq 0.1$ for $\\gtrsim$60$\\%$ of planet detections $\\geq$5 years after each microlensing event, for a simulated observ...

  12. Searching for intermediate-mass black holes in globular clusters with gravitational microlensing

    CERN Document Server

    Kains, N; Sahu, K C; Calamida, A

    2016-01-01

    We discuss the potential of the gravitational microlensing method as a unique tool to detect unambiguous signals caused by intermediate-mass black holes in globular clusters. We select clusters near the line of sight to the Galactic Bulge and the Small Magellanic Cloud, estimate the density of background stars for each of them, and carry out simulations in order to estimate the probabilities of detecting the astrometric signatures caused by black hole lensing. We find that for several clusters, the probability of detecting such an event is significant with available archival data from the Hubble Space Telescope. Specifically, we find that M 22 is the cluster with the best chances of yielding an IMBH detection via astrometric microlensing. If M 22 hosts an IMBH of mass $10^5M_\\odot$, then the probability that at least one star will yield a detectable signal over an observational baseline of 20 years is $\\sim 86\\%$, while the probability of a null result is around $14\\%$. For an IMBH of mass $10^6M_\\odot$, the ...

  13. Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System

    CERN Document Server

    Bennett, D P; Becker, A C; Butler, N; Dann, J H; Kaspi, S; Leibowitz, E M; Lipkin, Yu M; Maoz, D; Mendelson, H; Peterson, B A; Quinn, J; Shemmer, O; Thomson, S; Turner, S E

    1999-01-01

    The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not anticipated by theoretical work on the formation of planetary systems. Here we report observations and light curve modeling of gravitational microlensing event MACHO-97-BLG-41, which indicates that the lens system consists of a planet orbiting a binary star system. According to this model, the mass ratio of the binary star system is 3.8:1 and the stars are most likely to be a late K dwarf and an M dwarf with a separation of about 1.8 AU. A planet of about 3 Jupiter masses orbits this system at a distance of about 7 AU. If our interpretation of this light curve is correct, it represents the first discovery of a planet orbiting a binary star system and the first detection of a Jovian planet via the gravitational microlensing technique. It suggests that giant planets may be co...

  14. MOA-2011-BLG-293Lb: First Microlensing Planet possibly in the Habitable Zone

    CERN Document Server

    Batista, V; Gould, A; Bennett, D P; Yee, J C; Fukui, A; Gaudi, B S; Sumi, T; Udalski, A

    2013-01-01

    We used Keck adaptive optics observations to identify the first planet discovered by microlensing to lie in or near the habitable zone, i.e., at projected separation $r_\\perp=1.1\\pm 0.1\\,$AU from its $M_{L}=0.86\\pm 0.06\\,M_\\odot$ host, being the highest microlensing mass definitely identified. The planet has a mass $m_p = 4.8\\pm 0.3\\,M_{\\rm Jup}$, and could in principle have habitable moons. This is also the first planet to be identified as being in the Galactic bulge with good confidence: $D_L=7.7\\pm 0.44$ kpc. The planet/host masses and distance were previously not known, but only estimated using Bayesian priors based on a Galactic model (Yee et al. 2012). These estimates had suggested that the planet might be a super-Jupiter orbiting an M dwarf, a very rare class of planets. We obtained high-resolution $JHK$ images using Keck adaptive optics to detect the lens and so test this hypothesis. We clearly detect light from a G dwarf at the position of the event, and exclude all interpretations other than that th...

  15. Microlensing of the Broad Emission Line Region in the Quadruple Lens SDSS J1004+4112

    CERN Document Server

    Richards, G T; Pindor, B; Hennawi, J F; Hall, P B; Turner, E L; Inada, N; Oguri, M; Ichikawa, S I; Becker, R H; Gregg, M D; White, R L; Wyithe, J S B; Schneider, D P; Johnston, D E; Frieman, J A; Brinkmann, J; Richards, Gordon T.; Keeton, Charles R.; Pindor, Bartosz; Hennawi, Joseph F.; Hall, Patrick B.; Turner, Edwin L.; Inada, Naohisa; Oguri, Masamune; Ichikawa, Shin-Ichi; Becker, Robert H.; Gregg, Michael D.; White, Richard L.; Schneider, Donald P.; Johnston, David E.; Frieman, Joshua A.

    2004-01-01

    We present seven epochs of spectroscopy on the quadruply imaged quasar SDSS J1004+4112, spanning observed-frame time delays from 1 to 322 days. The spectra reveal differences in the emission lines between the lensed images. Specifically, component A showed a strong enhancement in the blue wings of several high-ionization lines relative to component B, which lasted at least 28 days (observed frame) then faded. Since the predicted time delay between A and B is <30 days, our time coverage suggests that the event was not intrinsic to the quasar. We attribute these variations to microlensing of part of the broad emission line region of the quasar, apparently resolving structure in the source plane on a scale of ~10^{16} cm at z=1.734. In addition, we observed smaller differences in the emission line profiles between components A and B that persisted throughout the time span, which may also be due to microlensing or millilensing. Further spectroscopic monitoring of this system holds considerable promise for reso...

  16. A New Channel to Search for Extra-solar Systems with Multiple Planets via Gravitational Microlensing

    CERN Document Server

    Han, C; Han, Cheongho; Park, Myeong-Gu

    2002-01-01

    Gaudi, Naber & Sackett pointed out that if an event is caused by a lens system containing more than two planets, all planets will affect the central region of the magnification pattern, and thus the existence of the multiple planets can be inferred by detecting additionally deformed anomalies from intensive monitoring of high magnification events. Unfortunately, this method has important limitations in identifying the existence of multiple planets and determining their parameters due to the degeneracy of the resulting light curve anomalies from those induced by a single planet and the complexity of multiple planet lensing models. In this paper, we propose a new channel to search for multiple planets via microlensing. The method is based on the fact that the anomalies induced by multiple planets are well approximated by the superposition of those of the single planet systems where the individual planet-primary pairs act as independent lens systems. Then, if the source trajectory passes both of the outer de...

  17. Events

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2016-02-01

    Full Text Available The 9th ARRCN Symposium 2015 was held during 21st–25th October 2015 at the Novotel Hotel, Chumphon, Thailand, one of the most favored travel destinations in Asia. The 10th ARRCN Symposium 2017 will be held during October 2017 in the Davao, Philippines. International Symposium on the Montagu's Harrier (Circus pygargus «The Montagu's Harrier in Europe. Status. Threats. Protection», organized by the environmental organization «Landesbund für Vogelschutz in Bayern e.V.» (LBV was held on November 20-22, 2015 in Germany. The location of this event was the city of Wurzburg in Bavaria.

  18. PROSPECTS FOR CHARACTERIZING HOST STARS OF THE PLANETARY SYSTEM DETECTIONS PREDICTED FOR THE KOREAN MICROLENSING TELESCOPE NETWORK

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Calen B., E-mail: henderson@astronomy.ohio-state.edu [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

    2015-02-10

    I investigate the possibility of constraining the flux of the lens (i.e., host star) for the types of planetary systems the Korean Microlensing Telescope Network is predicted to find. I examine the potential to obtain lens flux measurements by (1) imaging the lens once it is spatially resolved from the source, (2) measuring the elongation of the point-spread function of the microlensing target (lens+source) when the lens and source are still unresolved, and (3) taking prompt follow-up photometry. In each case I simulate the observing programs for a representative example of current ground-based adaptive optics (AO) facilities (specifically NACO on the Very Large Telescope), future ground-based AO facilities (GMTIFS on the Giant Magellan Telescope, GMT), and future space telescopes (NIRCAM on the James Webb Space Telescope, JWST). Given the predicted distribution of relative lens-source proper motions, I find that the lens flux could be measured to a precision of σ{sub H{sub ℓ}}≤0.1 for ≳60% of planet detections ≥5 yr after each microlensing event for a simulated observing program using GMT, which images resolved lenses. NIRCAM on JWST would be able to carry out equivalently high-precision measurements for ∼28% of events Δt = 10 yr after each event by imaging resolved lenses. I also explore the effects various blend components would have on the mass derived from prompt follow-up photometry, including companions to the lens, companions to the source, and unassociated interloping stars. I find that undetected blend stars would cause catastrophic failures (i.e., >50% fractional uncertainty in the inferred lens mass) for ≲ (16 · f {sub bin})% of planet detections, where f {sub bin} is the binary fraction, with the majority of these failures occurring for host stars with mass ≲0.3 M {sub ☉}.

  19. Long-term monitoring, time delay, and microlensing in the gravitational lens system Q0142-100

    Energy Technology Data Exchange (ETDEWEB)

    Oscoz, A.; Serra-Ricart, M.; Mediavilla, E. [Instituto de Astrofísica de Canarias, C. Vía Láctea s/n, E-38205 La Laguna (Spain); Muñoz, J. A. [Departamento de Astronomía y Astrofísica, Universidad de Valencia, E-46100-Burjassot, Valencia (Spain)

    2013-12-20

    We present 12 yr of monitoring of the gravitational lens Q0142-100 from the Teide Observatory. The data, taken from 1999 to 2010, comprise 105 observing nights with the IAC80 Telescope. The application of the δ{sup 2} method to the dataset leads to a value for the time delay between both components of the system of 72 ± 22 days (68% confidence level), consistent within uncertainties with the most recent results. With this value in mind a possible microlensing event is detected in Q0142-100.

  20. Constraining the Frequency of Free-floating Planets from a Synthesis of Microlensing, Radial Velocity, and Direct Imaging Survey Results

    Science.gov (United States)

    Clanton, Christian; Gaudi, B. Scott

    2017-01-01

    A microlensing survey by Sumi et al. exhibits an overabundance of short-timescale events (STEs; tE < 2 days) relative to what is expected from known stellar populations and a smooth power-law extrapolation down to the brown dwarf regime. This excess has been interpreted as a population of approximately Jupiter-mass objects that outnumber main-sequence stars nearly twofold; however the microlensing data alone cannot distinguish between events due to wide-separation (a ≳ 10 au) and free-floating planets. Assuming these STEs are indeed due to planetary-mass objects, we aim to constrain the fraction of these events that can be explained by bound but wide-separation planets. We fit the observed timescale distribution with a lens mass function comprised of brown dwarfs, main-sequence stars, and stellar remnants, finding and thus corroborating the initial identification of an excess of STEs. We then include a population of bound planets that are expected not to show signatures of the primary lens (host) in their microlensing light curves and that are also consistent with results from representative microlensing, radial velocity, and direct imaging surveys. We find that bound planets alone cannot explain the entire STE excess without violating the constraints from the surveys we consider and thus some fraction of these events must be due to free-floating planets, if our model for bound planets holds. We estimate a median fraction of STEs due to free-floating planets to be f = 0.67 (0.23 ≤ f ≤ 0.85 at 95% confidence) when assuming “hot-start” planet evolutionary models and f = 0.58 (0.14 ≤ f ≤ 0.83 at 95% confidence) for “cold-start” models. Assuming a delta-function distribution of free-floating planets of mass {m}p=2 {M}{Jup} yields a number of free-floating planets per main-sequence star of N = 1.4 (0.48 ≤ N ≤ 1.8 at 95% confidence) in the “hot-start” case and N = 1.2 (0.29 ≤ N ≤ 1.8 at 95% confidence) in the “cold-start” case.

  1. Weak microlensing effect and stability of pulsar time scale

    CERN Document Server

    Pshirkov, M S

    2006-01-01

    An influence of the weak microlensing effect on the pulsar timing is investigated for pulsar B1937+21. Average residuals of Time of Arrival (TOA) due to the effect would be as large as 10 ns in 20 years observation span. These residuals can be much greater (up to 1 ms in 20 years span) if pulsar is located in globular cluster (or behind it).

  2. OGLE-2015-BLG-0051/KMT-2015-BLG-0048Lb: A Giant Planet Orbiting a Low-mass Bulge Star Discovered by High-cadence Microlensing Surveys

    Science.gov (United States)

    Han, C.; Udalski, A.; Gould, A.; Bozza, V.; Jung, Y. K.; Albrow, M. D.; Kim, S.-L.; Lee, C.-U.; Cha, S.-M.; Kim, D.-J.; Lee, Y.; Park, B.-G.; Shin, I.-G.; KMTNet Collaboration; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Pawlak, M.; OGLE Collaboration

    2016-10-01

    We report the discovery of an extrasolar planet detected from the combined data of a microlensing event OGLE-2015-BLG-0051/KMT-2015-BLG-0048 acquired by two microlensing surveys. Despite the fact that the short planetary signal occurred in the very early Bulge season during which the lensing event could be seen for just about an hour, the signal was continuously and densely covered. From the Bayesian analysis using models of the mass function, and matter and velocity distributions, combined with information on the angular Einstein radius, it is found that the host of the planet is located in the Galactic bulge. The planet has a mass {0.72}-0.07+0.65 {M}{{J}} and it is orbiting a low-mass M-dwarf host with a projected separation {d}\\perp =0.73+/- 0.08 {{au}}. The discovery of the planet demonstrates the capability of the current high-cadence microlensing lensing surveys in detecting and characterizing planets.

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

    Science.gov (United States)

    Henderson, Calen B.; Poleski, Radosław; Penny, Matthew; Street, Rachel A.; Bennett, David P.; Hogg, David W.; Gaudi, B. Scott; K2 Campaign 9 Microlensing Science Team; 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.; OGLE Project, The; 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.; MOA Collaboration; Bachelet, E.; Bramich, D. M.; Cassan, A.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Hundertmark, M.; Mao, S.; Ranc, C.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Tsapras, Y.; Wambsganss, J.; RoboNet Project, The; Bozza, V.; Burgdorf, M. J.; Jørgensen, U. G.; Calchi Novati, S.; 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.; The MiNDSTEp Team; 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.; K2C9 Engineering Team; 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.; Wang, D.

    2016-12-01

    K2's Campaign 9 (K2C9) will conduct a ˜3.7 deg2 survey toward the Galactic bulge from 2016 April 22 through July 2 that will leverage the spatial separation between K2 and the Earth to facilitate measurement of the microlens parallax {π }{{E}} for ≳ 170 microlensing events. These will include several that are planetary in nature as well as many short-timescale microlensing events, which are potentially indicative of free-floating planets (FFPs). These satellite parallax measurements will in turn allow for the direct measurement of the masses of and distances to the lensing systems. In this article we provide an overview of the K2C9 space- and ground-based microlensing survey. Specifically, we detail the demographic questions that can be addressed by this program, including the frequency of FFPs and the Galactic distribution of exoplanets, the observational parameters of K2C9, and the array of resources dedicated to concurrent observations. Finally, we outline the avenues through which the larger community can become involved, and generally encourage participation in K2C9, which constitutes an important pathfinding mission and community exercise in anticipation of WFIRST.

  4. OGLE-2015-BLG-0051/KMT-2015-BLG-0048Lb: a Giant Planet Orbiting a Low-mass Bulge Star Discovered by High-cadence Microlensing Surveys

    CERN Document Server

    Han, C; Gould, A; Bozza, V; Jung, Y K; Albrow, M D; Kim, S -L; Lee, C -U; Cha, S -M; Kim, D -J; Lee, Y; Park, B -G; Shin, I -G; Szymański, M K; Soszyński, I; Skowron, J; Mróz, P; Poleski, R; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Wyrzykowski, Ł; Pawlak, M

    2016-01-01

    We report the discovery of an extrasolar planet detected from the combined data of a microlensing event OGLE-2015-BLG-0051/KMT-2015-BLG-0048 acquired by two microlensing surveys. Despite that the short planetary signal occurred in the very early Bulge season during which the lensing event could be seen for just about an hour, the signal was continuously and densely covered. From the Bayesian analysis using models of the mass function, matter and velocity distributions combined with the information of the angular Einstein radius, it is found that the host of the planet is located in the Galactic bulge. The planet has a mass $0.72_{-0.07}^{+0.65}\\ M_{\\rm J}$ and it is orbiting a low-mass M-dwarf host with a projected separation $d_\\perp=0.73 \\pm 0.08$ AU. The discovery of the planet demonstrates the capability of the current high-cadence microlensing lensing surveys in detecting and characterizing planets.

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

    CERN Document Server

    Henderson, Calen B; Street, Rachel A; Bennett, David P; Hogg, David W; Poleski, R; Barclay, T; Barentsen, G; Howell, S B; 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 A; 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; Akeson, R; Batista, V; Beaulieu, J -P; Beichman, C A; Bozza, V; Bryden, G; Ciardi, D; Cole, A; Coutures, C; Dong, S; Foreman-Mackey, D; Fouqué, P; Gaudi, B S; Kerins, E; Korhonen, H; Jørgensen, U; Lang, D; Lineweaver, C; Marquette, J -B; Mogavero, Federico; Morales, J C; Nataf, D; Pogge, R W; Santerne, A; Shvartzvald, Y; Suzuki, D; Tamura, M; Tisserand, P; Wang, D; Zhu, W

    2016-01-01

    $K2$'s Campaign 9 ($K2$C9) will conduct a $\\sim$3.4 deg$^{2}$ survey toward the Galactic bulge from 7/April through 1/July of 2016 that will leverage the spatial separation between $K2$ and the Earth to facilitate measurement of the microlens parallax $\\pi_{\\rm E}$ for $\\gtrsim$120 microlensing events, including several planetary in nature as well as many short-timescale microlensing events, which are potentially indicative of free-floating planets (FFPs). These satellite parallax measurements will in turn allow for the direct measurement of the masses of and distances to the lensing systems. In this white paper we provide an overview of the $K2$C9 space- and ground-based microlensing survey. Specifically, we detail the demographic questions that can be addressed by this program, including the frequency of FFPs and the Galactic distribution of exoplanets, the observational parameters of $K2$C9, and the array of ground-based resources dedicated to concurrent observations. Finally, we outline the avenues throug...

  6. MOA-2011-BLG-293LB: First microlensing planet possibly in the habitable zone

    Energy Technology Data Exchange (ETDEWEB)

    Batista, V.; Gould, A.; Yee, J. C.; Gaudi, B. S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, 98 Bis Boulevard Arago, F-75014 Paris (France); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Sumi, T. [Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Udalski, A., E-mail: virginie@astronomy.ohio-state.edu, E-mail: gould@astronomy.ohio-state.edu, E-mail: jyee@astronomy.ohio-state.edu, E-mail: beaulieu@iap.fr, E-mail: bennett@nd.edu, E-mail: afukui@oao.nao.ac.jp, E-mail: sumi@ess.sci.osaka-u.ac.jp, E-mail: udalski@astrouw.edu.pl [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland)

    2014-01-01

    We used Keck adaptive optics observations to identify the first planet discovered by microlensing to lie in or near the habitable zone, i.e., at projected separation r = 1.1 ± 0.1 AU from its M{sub L} = 0.86 ± 0.06 M {sub ☉} host, being the highest microlensing mass definitely identified. The planet has a mass m{sub p} = 4.8 ± 0.3 M {sub Jup}, and could in principle have habitable moons. This is also the first planet to be identified as being in the Galactic bulge with good confidence: D{sub L} = 7.72 ± 0.44 kpc. The planet/host masses and distance were previously not known, but only estimated using Bayesian priors based on a Galactic model. These estimates had suggested that the planet might be a super-Jupiter orbiting an M dwarf, a very rare class of planets. We obtained high-resolution JHK images using Keck adaptive optics to detect the lens and so test this hypothesis. We clearly detect light from a G dwarf at the position of the event, and exclude all interpretations other than that this is the lens with high confidence (95%), using a new astrometric technique. The calibrated magnitude of the planet host star is H{sub L} = 19.16 ± 0.13. We infer the following probabilities for the three possible orbital configurations of the gas giant planet: 53% to be in the habitable zone, 35% to be near the habitable zone, and 12% to be beyond the snow line, depending on the atmospherical conditions and the uncertainties on the semimajor axis.

  7. Adaptive PSF fitting - a highly performing photometric method and light curves of the GLS H1413+117: time delays and micro-lensing effects

    Science.gov (United States)

    Akhunov, T. A.; Wertz, O.; Elyiv, A.; Gaisin, R.; Artamonov, B. P.; Dudinov, V. N.; Nuritdinov, S. N.; Delvaux, C.; Sergeyev, A. V.; Gusev, A. S.; Bruevich, V. V.; Burkhonov, O.; Zheleznyak, A. P.; Ezhkova, O.; Surdej, J.

    2017-03-01

    We present new photometric observations of H1413+117 acquired during seasons between 2001 and 2008 in order to estimate the time delays between the lensed quasar images and to characterize at best the on-going micro-lensing events. We propose a highly performing photometric method called the adaptive point spread function fitting and have successfully tested this method on a large number of simulated frames. This has enabled us to estimate the photometric error bars affecting our observational results. We analysed the V- and R-band light curves and V-R colour variations of the A-D components which show short- and long-term brightness variations correlated with colour variations. Using the χ2 and dispersion methods, we estimated the time delays on the basis of the R-band light curves over the seasons between 2003 and 2006. We have derived the new values: ΔtAB = -17.4 ± 2.1, ΔtAC = -18.9 ± 2.8 and ΔtAD = 28.8 ± 0.7 d using the χ2 method (B and C are leading, D is trailing) with 1σ confidence intervals. We also used available observational constraints (resp. the lensed image positions, the flux ratios in mid-IR and two sets of time delays derived in the present work) to update the lens redshift estimation. We obtained z_l = 1.95^{+0.06}_{-0.10} which is in good agreement with previous estimations. We propose to characterize two kinds of micro-lensing events: micro-lensing for the A, B, C components corresponds to typical variations of ∼10-4 mag d-1 during all the seasons, while the D component shows an unusually strong micro-lensing effect with variations of up to ∼10-3 mag d-1 during 2004 and 2005.

  8. GERLUMPH Data Release 2: 2.5 billion simulated microlensing light curves

    CERN Document Server

    Vernardos, Georgios; Bate, Nicholas F; Croton, Darren; Vohl, Dany

    2015-01-01

    In the upcoming synoptic all--sky survey era of astronomy, thousands of new multiply imaged quasars are expected to be discovered and monitored regularly. Light curves from the images of gravitationally lensed quasars are further affected by superimposed variability due to microlensing. In order to disentangle the microlensing from the intrinsic variability of the light curves, the time delays between the multiple images have to be accurately measured. The resulting microlensing light curves can then be analyzed to reveal information about the background source, such as the size of the quasar accretion disc. In this paper we present the most extensive and coherent collection of simulated microlensing light curves; we have generated $>2.5$ billion light curves using the GERLUMPH high resolution microlensing magnification maps. Our simulations can be used to: train algorithms to measure lensed quasar time delays, plan future monitoring campaigns, and study light curve properties throughout parameter space. Our ...

  9. The MACHO Project HST Follow-Up: The Large Magellanic Cloud Microlensing Source Stars

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, C.A.; /LLNL, Livermore /UC, Berkeley; Drake, A.J.; /Caltech; Cook, K.H.; /LLNL, Livermore /UC, Berkeley; Bennett, D.P.; /Caltech /Notre Dame U.; Popowski, P.; /Garching, Max Planck Inst.; Dalal, N.; /Toronto U.; Nikolaev, S.; /LLNL, Livermore; Alcock, C.; /Caltech /Harvard-Smithsonian Ctr. Astrophys.; Axelrod, T.S.; /Arizona U.; Becker, A.C. /Washington U., Seattle; Freeman, K.C.; /Res. Sch. Astron. Astrophys., Weston Creek; Geha, M.; /Yale U.; Griest, K.; /UC, San Diego; Keller, S.C.; /LLNL, Livermore; Lehner, M.J.; /Harvard-Smithsonian Ctr. Astrophys. /Taipei, Inst. Astron. Astrophys.; Marshall, S.L.; /SLAC; Minniti, D.; /Rio de Janeiro, Pont. U. Catol. /Vatican Astron. Observ.; Pratt, M.R.; /Aradigm, Hayward; Quinn, P.J.; /Western Australia U.; Stubbs, C.W.; /UC, Berkeley /Harvard U.; Sutherland, W.; /Oxford U. /Oran, Sci. Tech. U. /Garching, Max Planck Inst. /McMaster U.

    2009-06-25

    We present Hubble Space Telescope (HST) WFPC2 photometry of 13 microlensed source stars from the 5.7 year Large Magellanic Cloud (LMC) survey conducted by the MACHO Project. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. None of these sources is coincident with a background galaxy, which rules out the possibility that the MACHO LMC microlensing sample is contaminated with misidentified supernovae or AGN in galaxies behind the LMC. This supports the conclusion that the MACHO LMC microlensing sample has only a small amount of contamination due to non-microlensing forms of variability. We compare the WFPC2 source star magnitudes with the lensed flux predictions derived from microlensing fits to the light curve data. In most cases the source star brightness is accurately predicted. Finally, we develop a statistic which constrains the location of the Large Magellanic Cloud (LMC) microlensing source stars with respect to the distributions of stars and dust in the LMC and compare this to the predictions of various models of LMC microlensing. This test excludes at {approx}> 90% confidence level models where more than 80% of the source stars lie behind the LMC. Exotic models that attempt to explain the excess LMC microlensing optical depth seen by MACHO with a population of background sources are disfavored or excluded by this test. Models in which most of the lenses reside in a halo or spheroid distribution associated with either the Milky Way or the LMC are consistent which these data, but LMC halo or spheroid models are favored by the combined MACHO and EROS microlensing results.

  10. Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF

    CERN Document Server

    Bensby, T; Feltzing, S; Johnson, J A; Gould, A; Cohen, J G; Asplund, M; Meléndez, J; Lucatello, S; Han, C; Thompson, I; Gal-Yam, A; Udalski, A; Bennett, D P; Bond, I A; Kohei, W; Sumi, T; Suzuki, D; Suzuki, K; Takino, S; Tristram, P; Yamai, N; Yonehara, A

    2012-01-01

    Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], we now have 58 microlensed bulge dwarfs and subgiants that have been homogeneously analysed. The main characteristics of the sample and the findings that can be drawn are: (i) The metallicity distribution (MDF) is wide and spans all metallicities between [Fe/H]=-1.9 to +0.6; (ii) The dip in the MDF around solar metallicity that was apparent in our previous analysis of a smaller sample (26 microlensed stars) is no longer evident; instead it has a complex structure and indications of multiple components are starting to emerge. [ABRIDGED]; (iii) The stars with [Fe/H]-0.1 show a wide variety of ages, ranging from 2 to 12 Gyr with a distribution that has a dominant peak around 4-5 Gyr and a tail towards higher ages; (v) There are indications in the [alpha/Fe] - [Fe/H] that the "knee" occurs around [Fe/H] = -0.3 to -0....

  11. On the Feasibility of Characterizing Free-floating Planets with Current and Future Space-based Microlensing Surveys

    CERN Document Server

    Henderson, Calen B

    2016-01-01

    Simultaneous space- and ground-based microlensing surveys, such as K2's Campaign 9 (K2C9) and $WFIRST$, facilitate measuring the masses and distances of free-floating planet (FFP) candidates. FFPs are identified as single-lens events with a short timescale, of-order 1 day. Measuring the mass of the lensing object requires determining the finite size of the source star $\\rho$, as well as the microlens parallax $\\pi_{\\rm E}$. A planet that is bound to but widely separated from a host star can produce a light curve similar to that of an FFP. This tension can be resolved with high-resolution imaging of the microlensing target to search for the lens flux $F_l$ from a possible host star. Here we investigate the accessible parameter space for each of these components --- $\\pi_{\\rm E}$, $\\rho$, and $F_l$ --- considering different satellites for a range of FFP masses, Galactic distances, and source star properties. We find that at the beginning of K2C9, when its projected separation from the Earth (as viewed from the ...

  12. A brown dwarf orbiting an M-dwarf

    DEFF Research Database (Denmark)

    Bachelet, E.; Fouqué, P.; Albrow, M.D.

    2012-01-01

    Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration....... Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event...

  13. Separating intrinsic and microlensing variability using parallax measurements

    CERN Document Server

    Haugan, S V H

    1995-01-01

    In gravitational lens systems with 3 or more resolved images of a quasar, the intrinsic variability may be unambiguously separated from the microlensing variability through parallax measurements from 3 observers when there is no relative motion of the lens masses (Refsdal 1993). In systems with fewer than 3 resolved images, however, this separation is not straightforward. A general approach that may be used for this purpose is presented. For simplicity, only the one-dimensional case is considered in detail: Given a well-sampled time series of the observed flux at two points in space with a known separation, choosing a velocity v_{\\perp} of the observers perpendicular to the line of sight determines the microlensing magnification history, and thereby also the intrinsic variability. The velocity is chosen by minimizing some measure (\\chi^2) of the residual intrinsic variability. In many cases this gives a close approximation to the true magnification. In cases where the relative motion of the lensing point mass...

  14. Dark Matter Fraction in Lens Galaxies: New Estimates from Microlensing

    CERN Document Server

    Jiménez-Vicente, J; Kochanek, C S; Muñoz, J A

    2014-01-01

    We present a joint estimate of the stellar/dark matter mass fraction in lens galaxies and the average size of the accretion disk of lensed quasars from microlensing measurements of 27 quasar image pairs seen through 19 lens galaxies. The maximum likelihood estimate for the fraction of the surface mass density in the form of stars is $\\alpha=0.2^{+0.1}_{-0.1}$ near the Einstein radius of the lenses ($\\sim 1 - 2$ effective radii). The estimate for the average accretion disk size is $r_s=6.0^{+3.0}_{-1.1}\\sqrt{M/0.3M_\\sun}$ light-days. The fraction of mass in stars at these radii is significantly larger than previous estimates from microlensing studies assuming quasars were point-like. The corresponding local dark matter fraction of 80\\ is in good agreement with other estimates based on strong lensing or kinematics. The size of the accretion disk inferred in the present study is slightly larger than previous estimates.

  15. The Exoplanet Microlensing Survey by the Proposed WFIRST Observatory

    Science.gov (United States)

    Barry, Richard; Kruk, Jeffrey; Anderson, Jay; Beaulieu, Jean-Philippe; Bennett, David P.; Catanzarite, Joseph; Cheng, Ed; Gaudi, Scott; Gehrels, Neil; Kane, Stephen; Lunine, Jonathan; Sumi, Takahiro; Tanner, Angelle; Traub, Wesley

    2012-01-01

    The New Worlds, New Horizons report released by the Astronomy and Astrophysics Decadal Survey Board in 2010 listed the Wide Field Infrared Survey Telescope (WFIRST) as the highest-priority large space mission for the . coming decade. This observatory will provide wide-field imaging and slitless spectroscopy at near infrared wavelengths. The scientific goals are to obtain a statistical census of exoplanets using gravitational microlensing. measure the expansion history of and the growth of structure in the Universe by multiple methods, and perform other astronomical surveys to be selected through a guest observer program. A Science Definition Team has been established to assist NASA in the development of a Design Reference Mission that accomplishes this diverse array of science programs with a single observatory. In this paper we present the current WFIRST payload concept and the expected capabilities for planet detection. The observatory. with science goals that are complimentary to the Kepler exoplanet transit mission, is designed to complete the statistical census of planetary systems in the Galaxy, from habitable Earth-mass planets to free floating planets, including analogs to all of the planets in our Solar System except Mercury. The exoplanet microlensing survey will observe for 500 days spanning 5 years. This long temporal baseline will enable the determination of the masses for most detected exoplanets down to 0.1 Earth masses.

  16. Confocal microscopy using variable-focal-length microlenses and an optical fiber bundle

    OpenAIRE

    Yang, Lisong; Mac Raighne, Aaron; McCabe, Eithne M.; Dunbar, L. Andrea; Scharf, Toralf

    2008-01-01

    The use of variable-focal-length (VFL) microlenses can provide a way to axially scan the foci across a sample by electronic control. We demonstrate an approach to coupling VFL microlenses individually to a fiber bundle as a way to create a high-throughput aperture array with a controllable aperture pattern. It would potentially be applied in real-time confocal imaging in vivo for biological specimens. The VFL microlenses that we used consist of a liquid-crystal film sandwiched between a pair ...

  17. Quasar structure from microlensing in gravitationally lensed quasars

    Science.gov (United States)

    Morgan, Christopher Warren

    2008-02-01

    I analyze microlensing in gravitationally lensed quasars to yield measurements of the structure of their continuum emission regions. I first describe our lensed quasar monitoring program and RETROCAM, the auxiliary port camera I built for the 2.4m Hiltner telescope to monitor lensed quasars. I describe the application of our Monte Carlo microlensing analysis technique to SDSS 0924+0219, a system with a highly anomalous optical flux ratio. For an inclination angle i, I find an optical scale radius log[( r s /cm)[Special characters omitted.] ] = [Special characters omitted.] . I extrapolate the best-fitting light curves into the future to find a roughly 45% probability that the anomalous image (D) will brighten by at least an order of magnitude during the next decade. I expand our method to make simultaneous estimates of the time delays and structure of HE1104-1805 and QJ0158-4325, two doubly-imaged quasars with microlensing and intrinsic variability on comparable time scales. For HE1104- 1805 I find a time delay of D t AB = t A - t B = [Special characters omitted.] days and estimate a scale radius of log[( r s /cm)[Special characters omitted.] ] = [Special characters omitted.] at 0.2mm in the rest frame. I am unable to measure a time delay for QJ0158-4325, but the scale radius is log[( r s /cm) [Special characters omitted.] ] = 14.9 ±1 0.3 at 0.3mm in the rest frame. I then apply our Monte Carlo microlensing analysis technique to the optical light curves of 11 lensed quasar systems to show that quasar accretion disk sizes at 2500Å are related to black hole mass ( M BH ) by log( R 2500 /cm) = (15.7 ± 0.16) + (0.64± 0.18) log( M BH /10 9 [Special characters omitted.] ). This scaling is consistent with the expectation from thin disk theory (R 0( [Special characters omitted.] ), but it implies that black holes radiate with relatively low efficiency, log(e) = -1.54 ± 0.36 + log( L/L E ) where e=3D L / ( M c 2 ). These sizes are also larger, by a factor of ~ 3, than

  18. A Search for Stellar-Mass Black Holes via Astrometric Microlensing

    CERN Document Server

    Lu, J R; Ofek, E O; Udalski, A; Kozlowski, S

    2016-01-01

    While dozens of stellar mass black holes have been discovered in binary systems, isolated black holes have eluded detection. Their presence can be inferred when they lens light from a background star. We attempt to detect the astrometric lensing signatures of three photometrically identified microlensing events, OGLE-2011-BLG-0022, OGLE-2011-BLG-0125, and OGLE-2012-BLG-0169 (OB110022, OB110125, and OB120169), located toward the Galactic Bulge. These events were selected because of their long durations, which statistically favors more massive lenses. Astrometric measurements were made over 1-2 years using laser-guided adaptive optics observations from the W. M. Keck Observatory. Lens model parameters were first constrained by the photometric light curves. The OB120169 light curve is well-fit by a single-lens model, while both OB110022 and OB110125 light curves favor binary-lens models. Using the photometric fits as prior information, no significant astrometric lensing signal was detected and all targets were c...

  19. On the Feasibility of Characterizing Free-floating Planets with Current and Future Space-based Microlensing Surveys

    Science.gov (United States)

    Henderson, Calen B.; Shvartzvald, Yossi

    2016-10-01

    Simultaneous space- and ground-based microlensing surveys, such as K2's Campaign 9 (K2C9) and WFIRST, facilitate measuring the masses and distances of free-floating planet (FFP) candidates, which are identified as single-lens events with timescales that are of the order of 1 day. Measuring the mass and distance of an FFP lens requires determining the size of the source star ρ, measuring the microlens parallax {π }{{E}}, and using high-resolution imaging to search for the lens flux {F}{\\ell } from a possible host star. Here we investigate the accessible parameter space for each of these components considering different satellites for a range of FFP masses, Galactic distances, and source star properties. We find that at the beginning of K2C9, when its projected separation {D}\\perp from the Earth is ≲0.2 au, it will be able to measure {π }{{E}} for Jupiter-mass FFP candidates at distances larger than ∼2 kpc and to Earth-mass lenses at ∼8 kpc. At the end of K2C9, when {D}\\perp = 0.81 au, it is sensitive to planetary-mass lenses for distances ≳3.5 kpc, and even then only to those with mass ≳M Jup. From lens flux constraints we find that it will be possible to exclude hosts down to the deuterium-burning limit for events within ∼2 kpc. This indicates that the ability to characterize FFPs detected during K2C9 is optimized for events occurring toward the beginning of the campaign. WFIRST, on the other hand, will be able to detect and characterize FFP masses down to or below super-Earths throughout the Galaxy during its entire microlensing survey.

  20. GERLUMPH Data Release 1: High-resolution cosmological microlensing magnification maps and eResearch tools

    CERN Document Server

    Vernardos, Georgios; Bate, Nicholas F; Croton, Darren

    2014-01-01

    As synoptic all-sky surveys begin to discover new multiply lensed quasars, the flow of data will enable statistical cosmological microlensing studies of sufficient size to constrain quasar accretion disc and supermassive black hole properties. In preparation for this new era, we are undertaking the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). We present here the GERLUMPH Data Release 1, which consists of 12342 high resolution cosmological microlensing magnification maps and provides the first uniform coverage of the convergence, shear and smooth matter fraction parameter space. We use these maps to perform a comprehensive numerical investigation of the mass-sheet degeneracy, finding excellent agreement with its predictions. We study the effect of smooth matter on microlensing induced magnification fluctuations. In particular, in the minima and saddle-point regions, fluctuations are enhanced only along the critical line, while in the maxima region they are always enhanced...

  1. Adventures in the microlensing cloud: large datasets, eResearch tools, and GPUs

    CERN Document Server

    Vernardos, Georgios

    2014-01-01

    As astronomy enters the petascale data era, astronomers are faced with new challenges relating to storage, access and management of data. A shift from the traditional approach of combining data and analysis at the desktop to the use of remote services, pushing the computation to the data, is now underway. In the field of cosmological gravitational microlensing, future synoptic all--sky surveys are expected to bring the number of multiply imaged quasars from the few tens that are currently known to a few thousands. This inflow of observational data, together with computationally demanding theoretical modelling via the production of microlensing magnification maps, requires a new approach. We present our technical solutions to supporting the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). This extensive dataset for cosmological microlensing modelling comprises over 70,000 individual magnification maps and ${\\sim}10^6$ related results. We describe our approaches to hosting, or...

  2. Biconvex Polymer Microlenses with Tunable Imaging Properties Designed by Janus Droplet Microfluidics

    Directory of Open Access Journals (Sweden)

    Takasi Nisisako

    2015-09-01

    Full Text Available This work presents a technique for fabricating biconvex polymer microlenses using microfluidics, and then evaluates their tunable optical properties. A glass microfluidic channel was employed to rapidly mass-produce nanoliter-sized biphasic Janus droplets, which consist of a biconvex segment of a photocurable monomer and a concave-convex segment of a non-curable silicone oil that contained a surfactant. Subsequent photopolymerization produces polymeric biconvex spherical microlenses with templated dual curvatures. By changing the flow-rate ratios of the photocurable and non-curable droplet phases in the microfluidic channel, the radii of curvature of the two lens surfaces and the thicknesses of the resultant microlenses can be varied. The resulting biconvex microlenses with different shapes were used in image projection experiments. Different magnification properties were observed, and were consistent with the properties estimated quantitatively from the geometrical parameters of the lenses.

  3. Microlensing light curve of a source on the other side of a wormhole

    CERN Document Server

    Tsukamoto, Naoki

    2016-01-01

    The observation of microlensing is a good probe into the topological structure of dark gravitating celestial objects. In this paper, we study the microlensing light curves due to light rays emitted by a source on the other side of a traversable wormhole. The present method will apply for general spherically symmetric traversable wormholes. Based on the obtained light curves, we discuss a possibility to observationally distinguish traversable wormholes with nontrivial topology from usual positive masses and other exotic objects without nontrivial topology.

  4. Limits on compact halo objects as dark matter from gravitational microlensing

    Directory of Open Access Journals (Sweden)

    Jetzer Philippe

    2014-04-01

    Full Text Available Microlensing started with the seminal paper by Paczyński in 1986 [1], first with observations towards the Large Magellanic Cloud and the galactic bulge. Since then many other targets have been observed and new applications have been found. In particular, it turned out to be a powerful method to detect planets in our galaxy and even in the nearby M31. Here, we will present some results obtained so far by microlensing without being, however, exhaustive.

  5. Common Radial Velocity vs. Rare Microlensing: Difficulties and Futures

    CERN Document Server

    Molaverdikhani, Karan

    2010-01-01

    In this paper, effective factors for success of Microlensing and Radial Velocity methods were choose. A semi-Delphi process applied on the factors to evaluating them and finding the most important factors for present situation of ML and RV, with help from about 100 experts, in or related exoplanets detection. I found the public definition on "success of exoplanets detection methods" is not correct and we should change it, as some experts did it, in the form of fundamental questions in planetary science. Also, the views of "Special Experts" are different from other experts that help us to choose the right way in evaluating. The next step was choosing the best strategy for future and finally, from SWOT landscape and with a new objective of ML method (New Game Board Strategy) I suggested four critical future strategies for completing current strategic directions.

  6. Microlensing in the double quasar SBS1520+530

    CERN Document Server

    Gaynullina, E R; Akhunov, T; Burkhonov, O M; Gottlöber, S; Mirtadjieva, K; Nuritdinov, S N; Tadjibaev, I; Wambsganss, J; Wisotzki, L

    2005-01-01

    We present the results of a monitoring campaign of the double quasar SBS1520+530 at Maidanak observatory from April 2003 to August 2004. We obtained light curves in V and R filters that show small-amplitude \\Delta m~0.1 mag intrinsic variations of the quasar on time scales of about 100 days. The data set is consistent with the previously determined time delay of \\Delta t=(130+-3) days by Burud et al. (2002). We find that the time delay corrected magnitude difference between the quasar images is now larger by (0.14+-0.03) mag than during the observations by Burud et al. (2002). This confirms the presence of gravitational microlensing variations in this system.

  7. Chromatic aberration control for tunable all-silicone membrane microlenses.

    Science.gov (United States)

    Waibel, Philipp; Mader, Daniel; Liebetraut, Peter; Zappe, Hans; Seifert, Andreas

    2011-09-12

    Tunable multi-chamber microfluidic membrane microlenses with achromaticity over a given focal length range are demonstrated. In analogy to a fixed-focus achromatic doublet lens, the multi-lens system is based on a stack of microfluidic cavities filled with optically optimized liquids with precisely defined refractive index and Abbe number, and these are independently pneumatically actuated. The membranes separating the cavities form the refractive optical surfaces, and the curvatures as a function of pressure are calculated using a mechanical model for deformation of flexible plates. The results are combined with optical ray tracing simulations of the multi-lens system to yield chromatic aberration behavior, which is verified experimentally. A focal length tuning range of 5-40 mm and reduction in chromatic aberration of over 30% is demonstrated, limited by the availability of optical fluids.

  8. Stellar masses calibrated with micro-lensed quasars

    CERN Document Server

    Schechter, Paul L; Pooley, David; Wambsganss, Joachim

    2014-01-01

    We measure the stellar mass surface densities of early type galaxies by observing the micro-lensing of macro-lensed quasars caused by individual stars, including stellar remnants, brown dwarfs and red dwarfs too faint to produce photometric or spectroscopic signatures. Our method measures the graininess of the gravitational potential, in contrast to methods that decompose a smooth total gravitational potential into two smooth components, one stellar and one dark. We find the median likelihood value for the calibration factor F by which Salpeter stellar masses (with a low mass cutoff of 0.1 solar masses) must be multiplied is 1.23, with a one sigma confidence range of 0.77 < F < 2.10.

  9. Studying wave optics in exoplanet microlensing light curves

    CERN Document Server

    Mehrabi, Ahmad

    2012-01-01

    We study the wave optics feature of the gravitational microlensing by a binary system composed of parent star and a planet. In the binary system, near the caustic lines multiple images play the role of secondary sources for the observer, in analogy to the double slit Young's experiment. In the case of having coherent wave fronts from the source on the lens plane, images can produce diffraction pattern on the observer plane. For the binary lensing system we have two modes of close and wide images around the planet and lens star and these images can produce two different types of fringes with the high and low frequencies on the observer plane. By taking into account the finite size of the source star, enhancements in the diffraction fringes get dimmer. For the observational prospects, we study this effect for the SKA project in the case of resonance and the high magnification exoplanet channels. This method can partially break degeneracies between the lens parameters.

  10. Quasar Structure from Microlensing in Gravitationally Lensed Quasars

    Science.gov (United States)

    Morgan, Christopher W.

    2007-12-01

    I investigate microlensing in gravitationally lensed quasars and discuss the use of its signal to probe quasar structure on small angular scales. I describe our lensed quasar optical monitoring program and RETROCAM, the optical camera I built for the 2.4m Hiltner telescope to monitor lensed quasars. I use the microlensing variability observed in 11 gravitationally lensed quasars to show that the accretion disk size at 2500Å is related to the black hole mass by log(R2500/cm) = (15.70±0.16) + (0.64±0.18)log(MBH/109M⊙). This scaling is consistent with the expectation from thin disk theory (R ∝ MBH2/3), but it implies that black holes radiate with relatively low efficiency, log(η) = -1.54±0.36 + log(L/LE) where η=L/(Mdotc2). With one exception, these sizes are larger by a factor of 4 than the size needed to produce the observed 0.8µm quasar flux by thermal radiation from a thin disk with the same T ∝ R-3/4 temperature profile. More sophisticated disk models are clearly required, particularly as our continuing observations improve the precision of the measurements and yield estimates of the scaling with wavelength and accretion rate. This research made extensive use of a Beowulf computer cluster obtained through the Cluster Ohio program of the Ohio Supercomputer Center. Support for program HST-GO-9744 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26666.

  11. Augmenting WFIRST Microlensing with a Ground-based Optical Telescope Network

    CERN Document Server

    Zhu, Wei

    2016-01-01

    Augmenting the WFIRST microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable one-dimensional (1-D) microlens parallax measurements over the entire mass range $M\\gtrsim M_\\oplus$. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging a few years after the observations. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. The addition of such a ground-based survey would also yield full 2-D vector parallax measurements, with largest sensitivity to low-mass lenses, which (being non-luminous) are not subject to followup imaging. These 2-D parallax measurements will directly yield mass and distance measurements for most planetary and binary events. It would also yield additional complete solutions for single-len...

  12. A Search For Stellar-mass Black Holes Via Astrometric Microlensing

    Science.gov (United States)

    Lu, J. R.; Sinukoff, E.; Ofek, E. O.; Udalski, A.; Kozlowski, S.

    2016-10-01

    While dozens of stellar-mass black holes (BHs) have been discovered in binary systems, isolated BHs have eluded detection. Their presence can be inferred when they lens light from a background star. We attempt to detect the astrometric lensing signatures of three photometrically identified microlensing events, OGLE-2011-BLG-0022, OGLE-2011-BLG-0125, and OGLE-2012-BLG-0169 (OB110022, OB110125, and OB120169), located toward the Galactic Bulge. These events were selected because of their long durations, which statistically favors more massive lenses. Astrometric measurements were made over one to two years using laser-guided adaptive optics observations from the W. M. Keck Observatory. Lens model parameters were first constrained by the photometric light curves. The OB120169 light curve is well fit by a single-lens model, while both OB110022 and OB110125 light curves favor binary lens models. Using the photometric fits as prior information, no significant astrometric lensing signal was detected and all targets were consistent with linear motion. The significant lack of astrometric signal constrains the lens mass of OB110022 to 0.05-1.79 M ⊙ in a 99.7% confidence interval, which disfavors a BH lens. Fits to OB110125 yielded a reduced Einstein crossing time and insufficient observations during the peak, so no mass limits were obtained. Two degenerate solutions exist for OB120169, which have a lens mass between 0.2-38.8 M ⊙ and 0.4-39.8 M ⊙ for a 99.7% confidence interval. Follow-up observations of OB120169 will further constrain the lens mass. Based on our experience, we use simulations to design optimal astrometric observing strategies and show that with more typical observing conditions the detection of BHs is feasible.

  13. An Extrasolar Planet Census with a Space-based Microlensing Survey

    CERN Document Server

    Bennett, D P; Beaulieu, J -P; Bond, I; Cheng, E; Cook, K; Friedman, S; Gaudi, B S; Gould, A; Jenkins, J; Kimble, R; Lin, D; Rich, M; Sahu, K; Tenerelli, D; Udalski, A; Yock, P

    2007-01-01

    A space-based gravitational microlensing exoplanet survey will provide a statistical census of exoplanets with masses down to 0.1 Earth-masses and orbital separations ranging from 0.5AU to infinity. This includes analogs to all the Solar System's planets except for Mercury, as well as most types of planets predicted by planet formation theories. Such a survey will provide results on the frequency of planets around all types of stars except those with short lifetimes. Close-in planets with separations < 0.5 AU are invisible to a space-based microlensing survey, but these can be found by Kepler. Other methods, including ground-based microlensing, cannot approach the comprehensive statistics on the mass and semi-major axis distribution of extrasolar planets that a space-based microlensing survey will provide. The terrestrial planet sensitivity of a ground-based microlensing survey is limited to the vicinity of the Einstein radius at 2-3 AU, and space-based imaging is needed to identify and determine the mass ...

  14. A Census of Exoplanets in Orbits Beyond 0.5 AU via Space-based Microlensing

    CERN Document Server

    Bennett, David P; Beaulieu, J -P; Bond, I; Cheng, E; Cook, K; Friedman, S; Gaudi, B S; Gould, A; Jenkins, J; Kimble, R; Lin, D; Mather, J; Rich, M; Sahu, K; Sumi, T; Tenerelli, D; Udalski, A; Yock, P

    2009-01-01

    A space-based gravitational microlensing exoplanet survey will provide a statistical census of exoplanets with masses greater than 0.1 Earth-masses and orbital separations ranging from 0.5AU to infinity. This includes analogs to all the Solar System's planets except for Mercury, as well as most types of planets predicted by planet formation theories. Such a survey will provide results on the frequency of planets around all types of stars except those with short lifetimes. Close-in planets with separations < 0.5 AU are invisible to a space-based microlensing survey, but these can be found by Kepler. Other methods, including ground-based microlensing, cannot approach the comprehensive statistics on the mass and semi-major axis distribution of extrasolar planets that a space-based microlensing survey will provide. The terrestrial planet sensitivity of a ground-based microlensing survey is limited to the vicinity of the Einstein radius at 2-3 AU, and space-based imaging is needed to identify and determine the ...

  15. GERLUMPH DATA RELEASE 1: HIGH-RESOLUTION COSMOLOGICAL MICROLENSING MAGNIFICATION MAPS AND eResearch TOOLS

    Energy Technology Data Exchange (ETDEWEB)

    Vernardos, G.; Fluke, C. J.; Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria, 3122 (Australia); Bate, N. F. [Sydney Institute for Astronomy, School of Physics, A28, University of Sydney, NSW, 2006 (Australia)

    2014-03-01

    As synoptic all-sky surveys begin to discover new multiply lensed quasars, the flow of data will enable statistical cosmological microlensing studies of sufficient size to constrain quasar accretion disk and supermassive black hole properties. In preparation for this new era, we are undertaking the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). We present here the GERLUMPH Data Release 1, which consists of 12,342 high resolution cosmological microlensing magnification maps and provides the first uniform coverage of the convergence, shear, and smooth matter fraction parameter space. We use these maps to perform a comprehensive numerical investigation of the mass-sheet degeneracy, finding excellent agreement with its predictions. We study the effect of smooth matter on microlensing induced magnification fluctuations. In particular, in the minima and saddle-point regions, fluctuations are enhanced only along the critical line, while in the maxima region they are always enhanced for high smooth matter fractions (≈0.9). We describe our approach to data management, including the use of an SQL database with a Web interface for data access and online analysis, obviating the need for individuals to download large volumes of data. In combination with existing observational databases and online applications, the GERLUMPH archive represents a fundamental component of a new microlensing eResearch cloud. Our maps and tools are publicly available at http://gerlumph.swin.edu.au/.

  16. The microlensing rate and distribution of free-floating planets towards the Galactic bulge

    CERN Document Server

    Ban, M; Robin, A C

    2016-01-01

    Ground-based optical microlensing surveys have provided tantalising, if inconclusive, evidence for a significant population of free-floating planets (FFPs). Both ground and space-based facilities are being used and developed which will be able to probe the distrubution of FFPs with much better sensitivity. It is vital also to develop a high-precision microlensing simulation framework to evaluate the completeness of such surveys. We present the first signal-to-noise limited calculations of the FFP microlensing rate using the Besancon Galactic model. The microlensing distribution towards the Galactic centre is simulated for wide-area ground-based optical surveys such as OGLE or MOA, a wide-area ground-based near-IR survey, and a targeted space-based near-IR survey which could be undertaken with Euclid or WFIRST. We present a calculation framework for the computation of the optical and near-infrared microlensing rate and optical depth for simulated stellar catalogues which are signal-to-noise limited, and take a...

  17. Integration of polystyrene microlenses with both convex and concave profiles in a polymer-based microfluidic system

    KAUST Repository

    Fan, Yiqiang

    2013-12-20

    This paper reports a new technique of fabricating polystyrene microlenses with both convex and concave profiles that are integrated in polymer-based microfluidic system. The polystyrene microlenses, or microlens array, are fabricated using the free-surface thermal compression molding method. The laser fabricated poly(methyl methacrylate) (PMMA) sheet is used as the mold for the thermal compression molding process. With different surface treatment methods of the PMMA mold, microlenses with either convex or concave profiles could be achieved during the thermal molding process. By integrating the microlenses in the microfluidic systems, observing the flow inside the microchannels is easier. This new technique is rapid, low cost, and it does not require cleanroom facilities. Microlenses with both convex and concave profiles can be easily fabricated and integrated in microfluidic system with this technique. © 2013 Springer-Verlag Berlin Heidelberg.

  18. A Radial Velocity Survey for LMC Microlensed Sources

    CERN Document Server

    Zhao, H S

    1999-01-01

    We propose a radial velocity survey with the aim to resolve the current dispute between the pro-macho camp and the pro-star camp on whether the lensing is caused by halo white dwarfs or machos in general or by stars in various observed or hypothesized structures of the Magellanic Clouds and the Galaxy. Star-star lensing should prefer sources at the backside or behind the LMC disc because lensing is most efficient if the source is located a few kpc behind a dense screen of stars, here the thin disc of the LMC. This signature of self-lensing can be looked for by a radial velocity survey since kinematics of the stars at the back can be markedly different from that of the majority of stars in the cold, rapidly rotating disc of the LMC. Detailed simulations of effect together with optimal strategies of carrying out the proposed survey are reported here. Assuming that the existing 30 or so alerted stars in the LMC are truely microlensed stars, their kinematics can test the two lensing scenarios; the confidence leve...

  19. On the microlensing optical depth of the galactic bar

    CERN Document Server

    Mao, S

    1996-01-01

    The microlensing probability (optical depth \\tau) toward the Galactic center carries information about the mass distribution of the Galactic bulge/bar, so can be used to constrain the very uncertain shape parameters of the bar. We find tau depends on the bar mass, radial profile, angle, axis scale lengths and boxyness by a few simple analytical formulae, which shows: (1) \\tau is proportional to the mass of the bar, M. (2) \\tau falls along the minor axis with a strong gradient. (3) An oblate bulge can have more optical depth than a triaxial bar if the bar angle \\alpha>45 degress. (4) \\tau is the largest if the angle \\alpha and the axis ratio y_0/x_0 conspires so that y_0/x_0=\\tan \\alpha. (5) At a fixed field on the minor axis but away from the center, boxy bars with a flat density profile tend to give a larger optical depth than ellipsoidal bars with a steep profile. (6) Main sequence sources should have a significantly lower (20-50\\% lower) optical depth than red clump giants if main sequence stars are not ob...

  20. Microlensing optical depth as a function of source apparent magnitude

    CERN Document Server

    Wood, Alexander

    2007-01-01

    Measurements of the microlensing optical depth, tau, towards the Galactic bulge appear to depend on the method used to obtain them. Those values based on the lensing of red clump giants (RCGs) appear to be significantly lower than those based on the lensing of all stars along the line of sight. This discrepancy is still not understood. Through Monte Carlo simulations, it is found that the discrepancy cannot be explained by a dependance on the flux limits of the two methods. The optical depth is expected to be generally constant as a function of source apparent magnitude for I_0 >~ 13.0, except in the range 13.5 <~ I_0 <~ 15.5. Here many RCGs are detected, causing a significant oscillation in tau. The amplitude of this oscillation is a function of the inclination angle of the Galactic bar, theta_bar, which may thus be constrained. A further constraint comes from a similar dependance of tau with theta_bar: combining the predicted trends with the measured values provides 1-sigma upper limits, which exclude...

  1. Simulations of the Fe K-alpha Energy Spectra from Gravitationally Microlensed Quasars

    CERN Document Server

    Krawczynski, Henric

    2016-01-01

    Chartas et al. (2012, 2016a,b) reported the discovery of multiple and energy variable peaks of the Fe K-alpha emission from the gravitationally lensed quasar RX J1131-1231. The authors explain the observations by the microlensing (produced by the stars of the lensing galaxy) of the emission from different regions of the accretion disk with different Doppler and gravitational frequency shifts. In this paper, we combine detailed simulations of the Fe K-alpha emission of the accretion disk in the Kerr spacetime of the black hole with calculations of the effect of gravitational microlensing on the observed energy spectra. The simulations give multiply peaked energy spectra similar to the observed ones. We explore the dependence of the spectral characteristics on black hole spin, accretion disk inclination, corona height, and microlensing amplification factor, and show that the measurements can be used to constrain these parameters. The detailed simulations described in this paper confirm the earlier constraints o...

  2. The Microlensing Planet Finder: Completing the Census of Extrasolar Planets in the Milky Way

    OpenAIRE

    Bennett, D. P.; Bond, I.; Cheng, E.; Friedman, S.; Garnavich, P.; Gaudi, B.; Gilliland, R.; Gould, A.; Greenhouse, M.; Griest, K.; Kimble, R.; Lunine, J.; Mather, J.; Minniti, D.; Niedner, M.

    2004-01-01

    The Microlensing Planet Finder (MPF) is a proposed Discovery mission that will complete the first census of extrasolar planets with sensitivity to planets like those in our own solar system. MPF will employ a 1.1m aperture telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order to detect extrasolar planets with the gravitational microlensing effect. MPF's sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect Earth-like planets at all separations fro...

  3. NASA ExoPAG Study Analysis Group 11: Preparing for the WFIRST Microlensing Survey

    CERN Document Server

    Yee, Jennifer C; Barry, Richard K; Bennett, David; Bryden, Geoff; Chung, Sun-Ju; Gaudi, B Scott; Gehrels, Neil; Gould, Andrew; Penny, Matthew T; Rattenbury, Nicholas; Ryu, Yoon-Hyun; Skowron, Jan; Street, Rachel; Sumi, Takahiro

    2014-01-01

    NASA's proposed WFIRST-AFTA mission will discover thousands of exoplanets with separations from the habitable zone out to unbound planets, using the technique of gravitational microlensing. The Study Analysis Group 11 of the NASA Exoplanet Program Analysis Group was convened to explore scientific programs that can be undertaken now, and in the years leading up to WFIRST's launch, in order to maximize the mission's scientific return and to reduce technical and scientific risk. This report presents those findings, which include suggested precursor Hubble Space Telescope observations, a ground-based, NIR microlensing survey, and other programs to develop and deepen community scientific expertise prior to the mission.

  4. Size of the accretion disk in the gravitationally lensed quasar SDSS J1004+4112 from the statistics of microlensing magnifications

    CERN Document Server

    Fian, C; Hanslmeier, A; Oscoz, A; Serra-Ricart, M; Muñoz, J A; Jiménez-Vicente, J

    2016-01-01

    We present eight monitoring seasons of the four brightest images of the gravitational lens SDSS J1004+4112 observed between December 2003 and October 2010. Using measured time delays for the images A, B and C and the model predicted time delay for image D we have removed the intrinsic quasar variability, finding microlensing events of about 0.5 and 0.7 mag of amplitude in the images C and D. From the statistics of microlensing amplitudes in images A, C, and D, we have inferred the half-light radius (at {\\lambda} rest = 2407 {\\AA}) for the accretion disk using two different methods, $R_{1/2}=8.7^{+18.5}_{-5.5} \\sqrt{M/0.3 M_\\odot}$ (histograms product) and $R_{1/2} = 4.2^{+3.2}_{-2.2} \\sqrt{M/0.3 M_\\odot}$ light-days ($\\chi^2$). The results are in agreement within uncertainties with the size predicted from the black hole mass in SDSS J1004+4112 using the thin disk theory.

  5. Mid-infrared microlensing of accretion disc and dusty torus in quasars: effects on flux ratio anomalies

    CERN Document Server

    Sluse, D; Anguita, T; Wucknitz, O; Wambsganss, J

    2013-01-01

    Multiply-imaged quasars and AGNs observed in the mid-infrared (MIR) range are commonly assumed to be unaffected by the microlensing produced by the stars in their lensing galaxy. In this paper, we investigate the validity domain of this assumption. Indeed, that premise disregards microlensing of the accretion disc in the MIR range, and does not account for recent progress in our knowledge of the dusty torus. To simulate microlensing, we first built a simplified image of the quasar composed of an accretion disc, and of a larger ring-like torus. The mock quasars are then microlensed using an inverse ray-shooting code. We simulated the wavelength and size dependence of microlensing for different lensed image types and fraction of compact objects projected in the lens. This allows us to derive magnification probabilities as a function of wavelength, as well as to calculate the microlensing-induced deformation of the spectral energy distribution of the lensed images. We find that microlensing variations as large a...

  6. Fabrication of Polydimethylsiloxane Microlenses Utilizing Hydrogel Shrinkage and a Single Molding Step

    Directory of Open Access Journals (Sweden)

    Bader Aldalali

    2014-05-01

    Full Text Available We report on polydimethlysiloxane (PDMS microlenses and microlens arrays on flat and curved substrates fabricated via a relatively simple process combining liquid-phase photopolymerization and a single molding step. The mold for the formation of the PDMS lenses is fabricated by photopolymerizing a polyacrylamide (PAAm pre-hydrogel. The shrinkage of PAAm after its polymerization forms concave lenses. The lenses are then transferred to PDMS by a single step molding to form PDMS microlens array on a flat substrate. The PAAm concave lenses are also transferred to PDMS and another flexible polymer, Solaris, to realize artificial compound eyes. The resultant microlenses and microlens arrays possess good uniformity and optical properties. The focal length of the lenses is inversely proportional to the shrinkage time. The microlens mold can also be rehydrated to change the focal length of the ultimate PDMS microlenses. The spherical aberration is 2.85 μm and the surface roughness is on the order of 204 nm. The microlenses can resolve 10.10 line pairs per mm (lp/mm and have an f-number range between f/2.9 and f/56.5. For the compound eye, the field of view is 113°.

  7. Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing

    Science.gov (United States)

    Mediavilla, E.; Jiménez-Vicente, J.; Muñoz, J. A.; Vives-Arias, H.; Calderón-Infante, J.

    2017-02-01

    The idea that dark matter can be made of intermediate-mass primordial black holes (PBHs) in the 10 M ⊙ ≲ M ≲ 200 M ⊙ range has recently been reconsidered, particularly in the light of the detection of gravitational waves by the LIGO experiment. The existence of even a small fraction of dark matter in black holes should nevertheless result in noticeable quasar gravitational microlensing. Quasar microlensing is sensitive to any type of compact objects in the lens galaxy, to their abundance, and to their mass. We have analyzed optical and X-ray microlensing data from 24 gravitationally lensed quasars to estimate the abundance of compact objects in a very wide range of masses. We conclude that the fraction of mass in black holes or any type of compact objects is negligible outside of the 0.05 M ⊙ ≲ M ≲ 0.45 M ⊙ mass range and that it amounts to 20% ± 5% of the total matter, in agreement with the expected masses and abundances of the stellar component. Consequently, the existence of a significant population of intermediate-mass PBHs appears to be inconsistent with current microlensing observations. Therefore, primordial massive black holes are a very unlikely source of the gravitational radiation detected by LIGO.

  8. Refractive microlenses produced by excimer laser machining of poly(methyl methacrylate)

    DEFF Research Database (Denmark)

    Jensen, Martin Frøhling; Krühne, Ulrich; H., L.;

    2005-01-01

    A method has been developed whereby refractive microlenses can be produced in poly (methyl methacrylate) by excimer laser irradiation at λ = 248 nm. The lenses are formed by a combined photochemical and thermal process. The lenses are formed as depressions in the substrate material (negative foca...

  9. Gravitational lens system SDSS J1339+1310: microlensing factory and time delay

    CERN Document Server

    Goicoechea, Luis J

    2016-01-01

    We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the $r$-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009$-$2016. These new data in both the wavelength and time domains have confirmed that the system is an unusual microlensing factory. The C$\\scriptsize{\\rm{IV}}$ emission line is remarkably microlensed, since the microlensing magnification of B relative to that for A, $\\mu_{\\rm{BA}}$, reaches a value of 1.4 ($\\sim$ 0.4 mag) for its core. Moreover, the B image shows a red wing enhancement of C$\\scriptsize{\\rm{IV}}$ flux (relative to A), and $\\mu_{\\rm{BA}}$ = 2 (0.75 mag) for the C$\\scriptsize{\\rm{IV}}$ broad-line emission. Regarding the nuclear continuum, we find a chromatic behaviour of $\\mu_{\\rm{BA}}$, which roughly varies from $\\sim$ 5 (1.75 mag) at 7000 \\AA\\ to $\\sim$ 6 (1.95 mag) at 4000 \\AA. We also detect significant microlensing variability in the $r$ band, and this includes a numb...

  10. Gravitational Microlensing of a Reverberating Quasar Broad Line Region - I. Method and Qualitative Results

    CERN Document Server

    Garsden, H; Lewis, G F

    2011-01-01

    The kinematics and morphology of the broad emission line region (BELR) of quasars are the subject of significant debate. The two leading methods for constraining BELR properties are microlensing and reverberation mapping. Here we combine these two methods with a study of the microlensing behaviour of the BELR in Q2237+0305, as a change in continuum emission (a "flare") passes through it. Beginning with some generic models of the BELR - sphere, bicones, disk - we slice in velocity and time to produce brightness profiles of the BELR over the duration of the flare. These are numerically microlensed to determine whether microlensing of reverberation mapping provides new information about the properties of BELRs. We describe our method and show images of the models as they are flaring, and the unlensed and lensed spectra that are produced. Qualitative results and a discussion of the spectra are given in this paper, highlighting some effects that could be observed. Our conclusion is that the influence of microlensi...

  11. Completing the Census of Exoplanets with the Microlensing Planet Finder (MPF)

    CERN Document Server

    Bennett, David P; Beaulieu, J -P; Bond, I; Cheng, E; Cook, K; Friedman, S; Gaudi, B S; Gould, A; Jenkins, J; Kimble, R; Lin, D; Mather, J; Rich, M; Sahu, K; Shao, M; Sumi, T; Tenerelli, D; Udalski, A; Yock, P

    2010-01-01

    The MPF mission will provide a statistical census of exoplanets with masses greater than 0.1 Earth-masses and orbital separations ranging from 0.5AU to infinity. This includes analogs to all the Solar System's planets except for Mercury, as well as most types of planets predicted by planet formation theories. Such a survey will provide results on the frequency of planets around all types of stars except those with short lifetimes. Close-in planets with separations < 0.5 AU are invisible to a space-based microlensing survey, but these can be found by Kepler. Other methods, including ground-based microlensing, cannot approach the comprehensive statistics on the mass and semi-major axis distribution of extrasolar planets that a space-based microlensing survey will provide. The terrestrial planet sensitivity of a ground-based microlensing survey is limited to the vicinity of the Einstein radius at 2-3 AU, and space-based imaging is needed to identify and determine the mass of the planetary host stars for the v...

  12. Microlensing discovery of a population of very tight, very low mass binary brown dwarfs

    DEFF Research Database (Denmark)

    Choi, J.-Y.; Han, C.; Udalski, A.

    2013-01-01

    the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M ☉ and 0.034 M ☉, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known...

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

    DEFF Research Database (Denmark)

    Kains, N.; Street, R.A.; Choi, J.-Y.;

    2013-01-01

    curve, we find that the lens is composed of two masses with a mass ratio q = 1.9 × 10-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. Results. We...... find that the lens is made up of a planet of mass 0.53 ± 0.21 M J orbiting an M dwarf host star with a mass of 0.26 ± 0.11 M⊙. The planetary system is located at a distance of 2.57 ± 0.61 kpc towards the Galactic centre. The projected separation of the planet from its host star is d = 1.408 ± 0.......019, in units of the Einstein radius, which corresponds to 2.72 ± 0.75 AU in physical units. We also identified a competitive model with similar planet and host star masses, but with a smaller orbital radius of 1.50 ± 0.50 AU. The planet is therefore located beyond the snow line of its host star, which we...

  14. Gaia16aye is a binary microlensing event and is crossing the caustic again

    Science.gov (United States)

    Wyrzykowski, L.; Leto, G.; Altavilla, G.; Bakis, V.; Britavskiy, N.; Burgaz, U.; Butterley, T.; Carrasco, J. M.; Dhillon, V. S.; Dominik, M.; Gomboc, A.; Hardy, L. K.; Littlefair, S. P.; Maund, J. R.; Piascik, A.; Rhodes, L.; Sanchez, R. Z.; Sokolovsky, K. V.; Steele, I.; Wilson, R. W.; Hamanowicz, A.; Mroz, P.; Pawlak, M.; Rybicki, K.; Sitek, M.; Mikolajczyk, P.; Kolaczkowski, Z.; Street, R.; Bendjoya, P.; Bozza, V.; Dziedzic, J.; Niczyj, K.; Nowicki, R.; Porebski, M.

    2016-09-01

    Galactic Plane (Cygnus) transient, Gaia16aye, nicknamed Ayers Rock (19:40:01.13 +30:07:53.4, J2000), was discovered by Gaia Science Alerts, http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia16aye, on 2016-08-05 as a flare on an otherwise quiet star.

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

    DEFF Research Database (Denmark)

    Kains, N.; Street, R.A.; Choi, J.-Y.

    2013-01-01

    find that the lens is made up of a planet of mass 0.53 ± 0.21 M J orbiting an M dwarf host star with a mass of 0.26 ± 0.11 M⊙. The planetary system is located at a distance of 2.57 ± 0.61 kpc towards the Galactic centre. The projected separation of the planet from its host star is d = 1.408 ± 0...

  16. A microlensing study of the accretion disc in the quasar MG 0414+0534

    CERN Document Server

    Bate, N F; Webster, R L; Wyithe, J S B

    2008-01-01

    Observations of gravitational microlensing in multiply imaged quasars currently provide the only direct probe of quasar emission region structure on sub-microarcsecond scales. Analyses of microlensing variability are observationally expensive, requiring long-term monitoring of lensed systems. Here we demonstrate a technique for constraining the size of the quasar continuum emission region as a function of wavelength using single-epoch multi-band imaging. We have obtained images of the lensed quasar MG 0414+0534 in five wavelength bands using the Magellan 6.5-metre Baade telescope at Las Campanas Observatory, Chile. These data, in combination with two existing epochs of Hubble Space Telescope data, are used to model the size of the continuum emission region $\\sigma$ as a power-law in wavelength, $\\sigma\\propto\\lambda^\

  17. Designing Fresnel microlenses for focusing astigmatic multi-Gaussian beams by using fractional order Fourier transforms

    Energy Technology Data Exchange (ETDEWEB)

    Patino, A [Universidad Technologica de Bolivar, Cartagena de Indias (Colombia); Durand, P-E; Fogret, E; Pellat-Finet, P, E-mail: alberto.patino-vanegas@univ-ubs.fr [Laboratoire de mathematiques et applications des mathematiques, Universite de Bretagne Sud, B P 92116, 56321 Lorient cedex (France)

    2011-01-01

    According to a scalar theory of diffraction, light propagation can be expressed by two-dimensional fractional order Fourier transforms. Since the fractional Fourier transform of a chirp function is a Dirac distribution, focusing a light beam is optically achieved by using a diffractive screen whose transmission function is a two-dimensional chirp function. This property is applied to designing Fresnel microlenses, and the orders of the involved Fourier fractional transforms depend on diffraction distances as well as on emitter and receiver radii of curvature. If the emitter is astigmatic (with two principal radii of curvature), the diffraction phenomenon involves two one-dimensional fractional Fourier transforms whose orders are different. This degree of freedom allows us to design microlenses that can focus astigmatic Gaussian beams, as produced by a line-shaped laser diode source.

  18. Micro-lensed single-mode optical fiber with high numerical aperture

    CERN Document Server

    Kato, Shinya; Aoki, Takao

    2013-01-01

    We show that the output mode of a single-mode optical fiber can be directly focused to a sub-wavelength waist with a finite working distance by tapering the fiber to a diameter of the order of the wavelength and terminating it with a spherically/hemispherically shaped tip. Numerical simulations show that a beam waist with a width of as small as 0.62\\lambda can be formed. We fabricate micro-lensed fibers and construct a probe-scanning confocal reflection microscope. Measurements on gold nano-particles show a spatial profile with a width of 0.29\\lambda for \\lambda = 850 nm, which is in good agreement with the numerical simulations. Due to their monolithic structures, these micro-lensed fibers will be flexible substitutes for conventional compound lenses in various experimental conditions such as cryogenic temperature and ultra-high vacuum.

  19. MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.-Y.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Gaudi, B. S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Dominik, M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Beaulieu, J.-P. [Institut dAstrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Drive, Goleta, CA 93117 (United States); Bozza, V. [INFN, Sezione di Napoli, I-80126 Napoli (Italy); Abe, F.; Furusawa, K.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Chote, P. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Collaboration: MOA Collaboration; OGLE Collaboration; muFUN Collaboration; MiNDSTEp Consortium; PLANET Collaboration; RoboNet Collaboration; and others

    2013-05-10

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

  20. Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown Dwarfs

    CERN Document Server

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

    2013-01-01

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

  1. Optical characterization method for very small microlenses (sub-50 micron) for industrial mass-production applications

    Science.gov (United States)

    Kim, Myun-Sik; Sunarjo, Jonathan; Weible, Kenneth J.; Voelkel, Reinhard

    2013-04-01

    We present several characterization techniques, which are suitable for small-size microlenses of lens diameters down to 5 μm. For an individual microlens, we apply full characterization for optical performance and surface characteristics. First, the optical performance is characterized by using a high-resolution interference microscope (HRIM). Second, a confocal microscope is applied to investigate the surface parameters. Third, the HRIM allows scanning the microlens array along the optical axis by using a piezo actuator. This leads to a measurement of the 3D intensity distribution near the focus of the lens. Such 3D intensity maps allow us to characterize the focal properties of each lens in an array. By studying those characterization techniques, we develop a new method to characterize a large number of microlenses, for instance, over one million lenses, which is already applied to wafer-based manufacturing in a cleanroom fab.

  2. Formation of Polymeric Hollow Microcapsules and Microlenses Using Gas-in-Organic-in-Water Droplets

    Directory of Open Access Journals (Sweden)

    Dong Hyun Yoon

    2015-05-01

    Full Text Available This paper presents methods for the formation of hollow microcapsules and microlenses using multiphase microdroplets. Microdroplets, which consist of a gas core and an organic phase shell, were generated at a single junction on a silicon device without surface treatment of the fluidic channels. Droplet, core and shell dimensions were controlled by varying the flow rates of each phase. When the organic solvent was released from the organic phase shell, the environmental conditions changed the shape of the solidified polymer shell to either a hollow capsule or a microlens. A uniform solvent release process produced polymeric capsules with nanoliter gas core volumes and a membrane thickness of approximately 3 μm. Alternatively physical rearrangement of the core and shell allowed for the formation of polymeric microlenses. On-demand formation of the polymer lenses in wells and through-holes polydimethylsiloxane (PDMS structures was achieved. Optical properties of the lenses were controlled by changing the dimension of these structures.

  3. A simple focal-length measurement technique for adaptive microlenses using z-scan

    Science.gov (United States)

    Abdelaziez, Yasser; Banerjee, Partha P.

    2004-10-01

    A simple technique for focal length measurements of adaptive micro-lenses using z-scan is reported. Focal length is one of the most important parameters of any lens. The effective focal length is measured with reference to the principal points that are not easy to find especially for micro-lenses. In addition, variable focal length microlenses pose a different challenge that makes the process of determining their exact focal length a tedious and difficult process. Classical methods such as nodal slide and magnification have been used for focal length determination. Also, advanced Interference techniques such as Talbot, Moire, Digital Speckle, Zygo and Joint Fourier Transform were used for focal length measurements. These techniques require more elaborate setups and difficult to implement, especially for microlenses. Recently a power meter was used to find the focal length of an unknown lens. Most of the techniques mentioned above proof to be not simple for microlens characterization. The z-scan technique has been implemented, for quite sometimes, to characterize the third-order effects of a nonlinear optical material. The z-scan provides information on both the sign and magnitude of the non-linear refractive index and offer advantage of simplicity. We have used a regular lens to collimate and focus light unto the lens under test. By scanning the lens under test and measuring the on-axis intensity, one can find the focal length. This is because the on-axis intensity is proportional to the phase of the lens and therefore the focal length. In the case of an adaptive lens with its focal length is a function of the applied voltage, the scanning occurs for each voltage value that will correspond to the on-axis refractive index change and therefore the far field on-axis intensity. This described technique above is easy to implement and can achieve good accuracy due to the inherent sensitivity of the z-scan.

  4. Adventures in the microlensing cloud: Large datasets, eResearch tools, and GPUs

    Science.gov (United States)

    Vernardos, G.; Fluke, C. J.

    2014-10-01

    As astronomy enters the petascale data era, astronomers are faced with new challenges relating to storage, access and management of data. A shift from the traditional approach of combining data and analysis at the desktop to the use of remote services, pushing the computation to the data, is now underway. In the field of cosmological gravitational microlensing, future synoptic all-sky surveys are expected to bring the number of multiply imaged quasars from the few tens that are currently known to a few thousands. This inflow of observational data, together with computationally demanding theoretical modeling via the production of microlensing magnification maps, requires a new approach. We present our technical solutions to supporting the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). This extensive dataset for cosmological microlensing modeling comprises over 70 000 individual magnification maps and ˜106 related results. We describe our approaches to hosting, organizing, and serving ˜ 30 TB of data and metadata products. We present a set of online analysis tools developed with PHP, JavaScript and WebGL to support access and analysis of GELRUMPH data in a Web browser. We discuss our use of graphics processing units (GPUs) to accelerate data production, and we release the core of the GPU-D direct inverse ray-shooting code (Thompson et al., 2010, 2014) used to generate the magnification maps. All of the GERLUMPH data and tools are available online from http://gerlumph.swin.edu.au. This project made use of gSTAR, the GPU Supercomputer for Theoretical Astrophysical Research.

  5. A new probe of the small-scale primordial power spectrum: astrometric microlensing by ultracompact minihalos

    CERN Document Server

    Li, Fangda; Law, Nicholas M

    2012-01-01

    The dark matter enclosed in a density perturbation with a large initial amplitude (delta-rho/rho > 1e-3) collapses shortly after recombination and forms an ultracompact minihalo (UCMH). Their high central densities make UCMHs especially suitable for detection via astrometric microlensing: as the UCMH moves, it changes the apparent position of background stars. A UCMH with a mass larger than a few solar masses can produce a distinctive astrometric microlensing signal that is detectable by the space astrometry mission Gaia. If Gaia does not detect gravitational lensing by any UCMHs, then it establishes an upper limit on their abundance and constrains the amplitude of the primordial power spectrum for k~3500 Mpc^{-1}. These constraints complement the upper bound on the amplitude of the primordial power spectrum derived from limits on gamma-ray emission from UCMHs because the astrometric microlensing signal produced by an UCMH is maximized if the dark-matter annihilation rate is too low to affect the UCMH's densi...

  6. Microlensing of the broad-line region in the quadruply imaged quasar HE0435-1223

    CERN Document Server

    Braibant, L; Sluse, D; Anguita, T; García-Vergara, C J

    2014-01-01

    Using infrared spectra of the z = 1.693 quadruply lensed quasar HE0435-1223 acquired in 2009 with the spectrograph SINFONI at the ESO Very Large Telescope, we have detected a clear microlensing effect in images A and D. While microlensing affects the blue and red wings of the H{\\alpha} line profile in image D very differently, it de-magnifies the line core in image A. The combination of these different effects sets constraints on the line-emitting region; these constraints suggest that a rotating ring is at the origin of the H{\\alpha} line. Visible spectra obtained in 2004 and 2012 indicate that the MgII line profile is microlensed in the same way as the H{\\alpha} line. Our results therefore favour flattened geometries for the low-ionization line-emitting region, for example, a Keplerian disk. Biconical models cannot be ruled out but require more fine-tuning. Flux ratios between the different images are also derived and confirm flux anomalies with respect to estimates from lens models with smooth mass distrib...

  7. Gravitational Microlensing: A Tool for Detecting and Characterizing Free-Floating Planets

    CERN Document Server

    Han, C; Kim, D; Park, B G; Ryu, Y H; Kang, S; Lee, D W; Han, Cheongho; Chung, Sun-Ju; Kim, Doeon; Park, Byeong-Gon; Ryu, Yoon-Hyun; Kang, Sangjun; Lee, Dong Wook

    2004-01-01

    Various methods have been proposed to search for extrasolar planets. Compared to the other methods, microlensing has unique applicabilities to the detections of Earth-mass and free-floating planets. However, the microlensing method is seriously flawed by the fact that the masses of the detected planets cannot be uniquely determined. Recently, Gould, Gaudi, & Han introduced an observational setup that enables one to resolve the mass degeneracy of the Earth-mass planets. The setup requires a modest adjustment to the orbit of an already proposed Microlensing planet-finder satellite combined with ground-based observations. In this paper, we show that a similar observational setup can also be used for the mass determinations of free-floating planets with masses ranging from ~0.1 M_J to several Jupiter masses. If the proposed observational setup is realized, the future lensing surveys will play important roles in the studies of Earth-mass and free-floating planets, which are the populations of planets that have...

  8. One or more bound planets per Milky Way star from microlensing observations.

    Science.gov (United States)

    Cassan, A; Kubas, D; Beaulieu, J-P; Dominik, M; Horne, K; Greenhill, J; Wambsganss, J; Menzies, J; Williams, A; Jørgensen, U G; Udalski, A; Bennett, D P; Albrow, M D; Batista, V; Brillant, S; Caldwell, J A R; Cole, A; Coutures, Ch; Cook, K H; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouqué, P; Hill, K; Kains, N; Kane, S; Marquette, J-B; Martin, R; Pollard, K R; Sahu, K C; Vinter, C; Warren, D; Watson, B; Zub, M; Sumi, T; Szymański, M K; Kubiak, M; Poleski, R; Soszynski, I; Ulaczyk, K; Pietrzyński, G; Wyrzykowski, L

    2012-01-11

    Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10 AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10 M(J), where M(J) = 318 M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30 M(⊕)) and super-Earths (5-10 M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception.

  9. MOA-2008-BLG-379Lb: A Massive Planet from a High Magnification Event with a Faint Source

    CERN Document Server

    Suzuki, D; Sumi, T; Bennett, D P; Bond, I A; Abe, F; Botzler, C S; Freeman, M; Fukagawa, M; Fukui, A; Furusawa, K; Itow, Y; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Ohnishi, K; Rattenbury, N; Saito, To; Shibai, H; Sullivan, D J; Suzuki, K; Sweatman, W L; Takino, S; Tristram, P J; Wada, K; Yock, P C M; Szymański, M K; Kubiak, M; Soszyński, I; Pietrzyński, G; Poleski, R; Ulaczyk, K; Wyrzykowski, Ł

    2013-01-01

    We report analysis of high microlensing event MOA-2008-BLG-379, which has a strong microlensing anomaly at its peak, due to a massive planet with a mass ratio of q = 6.9 x 10^{-3}. Because the faint source star crosses the large resonant caustic, the planetary signal dominates the light curve. This is unusual for planetary microlensing events, and as a result, the planetary nature of this light curve was not immediately noticed. The planetary nature of the event was found when the MOA Collaboration conducted a systematic study of binary microlensing events previously identified by the MOA alert system. We have conducted a Bayesian analysis based on a standard Galactic model to estimate the physical parameters of the lens system. This yields a host star mass of M_L = 0.66_{-0.33}^{+0.29} M_Sun orbited by a planet of mass m_P = 4.8_{-2.4}^{+2.1} M_Jup at an orbital separation of a = 4.1_{-1.5}^{+1.9} AU at a distance of D_L = 3.6 +/- 1.3 kpc. The faint source magnitude of I_S = 21.30 and relatively high lens-so...

  10. The different origins of high- and low-ionization broad emission lines revealed by gravitational microlensing in the Einstein cross

    Science.gov (United States)

    Braibant, L.; Hutsemékers, D.; Sluse, D.; Anguita, T.

    2016-07-01

    We investigate the kinematics and ionization structure of the broad emission line region of the gravitationally lensed quasar QSO2237+0305 (the Einstein cross) using differential microlensing in the high- and low-ionization broad emission lines. We combine visible and near-infrared spectra of the four images of the lensed quasar and detect a large-amplitude microlensing effect distorting the high-ionization CIV and low-ionization Hα line profiles in image A. While microlensing only magnifies the red wing of the Balmer line, it symmetrically magnifies the wings of the CIV emission line. Given that the same microlensing pattern magnifies both the high- and low-ionization broad emission line regions, these dissimilar distortions of the line profiles suggest that the high- and low-ionization regions are governed by different kinematics. Since this quasar is likely viewed at intermediate inclination, we argue that the differential magnification of the blue and red wings of Hα favors a flattened, virialized, low-ionization region whereas the symmetric microlensing effect measured in CIV can be reproduced by an emission line formed in a polar wind, without the need of fine-tuned caustic configurations. Based on observations made with the ESO-VLT, Paranal, Chile; Proposals 076.B-0197 and 076.B-0607 (PI: Courbin).

  11. Post-Decadal White Paper: A Dual-Satellite Dark-Energy/Microlensing NASA-ESA Mission

    CERN Document Server

    Gould, Andrew

    2010-01-01

    A confluence of scientific, financial, and political factors imply that launching two simpler, more narrowly defined dark-energy/microlensing satellites will lead to faster, cheaper, better (and more secure) science than the present EUCLID and WFIRST designs. The two satellites, one led by ESA and the other by NASA, would be explicitly designed to perform complementary functions of a single, dual-satellite dark-energy/microlensing ``mission''. One would be a purely optical wide-field camera, with large format and small pixels, optimized for weak-lensing, which because of its simple design, could be launched by ESA on relatively short timescales. The second would be a purely infrared satellite with marginally-sampled or under-sampled pixels, launched by NASA. Because of budget constraints, this would be launched several years later. The two would complement one another in 3 dark energy experiments (weak lensing, baryon oscillations, supernovae) and also in microlensing planet searches. Signed international agr...

  12. Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF

    Science.gov (United States)

    Bensby, T.; Yee, J. C.; Feltzing, S.; Johnson, J. A.; Gould, A.; Cohen, J. G.; Asplund, M.; Meléndez, J.; Lucatello, S.; Han, C.; Thompson, I.; Gal-Yam, A.; Udalski, A.; Bennett, D. P.; Bond, I. A.; Kohei, W.; Sumi, T.; Suzuki, D.; Suzuki, K.; Takino, S.; Tristram, P.; Yamai, N.; Yonehara, A.

    2013-01-01

    Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. Combined with the sample of 26 stars from the previous papers in this series, we now have 58 microlensed bulge dwarfs and subgiants that have been homogeneously analysed. The main characteristics of the sample and the findings that can be drawn are: (i) the metallicity distribution (MDF) is wide and spans all metallicities between [Fe/H] = -1.9 to +0.6; (ii) the dip in the MDF around solar metallicity that was apparent in our previous analysis of a smaller sample (26 microlensed stars) is no longer evident; instead it has a complex structure and indications of multiple components are starting to emerge. A tentative interpretation is that there could be different stellar populations at interplay, each with a different scale height: the thin disk, the thick disk, and a bar population; (iii) the stars with [Fe/H] ≲ -0.1 are old with ages between 10 and 12 Gyr; (iv) the metal-rich stars with [Fe/H] ≳ -0.1 show a wide variety of ages, ranging from 2 to 12 Gyr with a distribution that has a dominant peak around 4-5 Gyr and a tail towards higher ages; (v) there are indications in the [α/Fe]-[Fe/H] abundance trends that the "knee" occurs around [Fe/H] = -0.3to -0.2, which is a slightly higher metallicity as compared to the "knee" for the local thick disk. This suggests that the chemical enrichment of the metal-poor bulge has been somewhat faster than what is observed for the local thick disk. The results from the microlensed bulge dwarf stars in combination with other findings in the literature, in particular the evidence that the bulge has cylindrical rotation, indicate that the Milky Way could be an almost pure disk galaxy. The bulge would then just be a conglomerate of the other Galactic stellar populations (thin disk, thick disk, halo, and ...?), residing together in the central

  13. Event Discovery in Time Series

    CERN Document Server

    Preston, Dan; Brodley, Carla

    2009-01-01

    The discovery of events in time series can have important implications, such as identifying microlensing events in astronomical surveys, or changes in a patient's electrocardiogram. Current methods for identifying events require a sliding window of a fixed size, which is not ideal for all applications and could overlook important events. In this work, we develop probability models for calculating the significance of an arbitrary-sized sliding window and use these probabilities to find areas of significance. Because a brute force search of all sliding windows and all window sizes would be computationally intractable, we introduce a method for quickly approximating the results. We apply our method to over 100,000 astronomical time series from the MACHO survey, in which 56 different sections of the sky are considered, each with one or more known events. Our method was able to recover 100% of these events in the top 1% of the results, essentially pruning 99% of the data. Interestingly, our method was able to iden...

  14. Solving the long-standing discrepancy in the Microlensing Optical Depth Toward the Galactic Bulge by correcting the stellar number count

    CERN Document Server

    Sumi, T

    2016-01-01

    We find that significant incompleteness in stellar number counts results in a significant overestimate of the microlensing optical depth $\\tau$ and event rate per star per year $\\Gamma$ toward the Galactic bulge from the first two years of MOA-II survey. We find that the completeness in Red Clump Giant (RCG) counts $f_{\\rm RC}$ decreases proportional to the galactic latitude $b$, as $f_{\\rm RC}=(0.63\\pm0.11)-(0.052\\pm0.028)\\times b$, ranging 1-0.7 at $b=-6^\\circ\\sim-1.5^\\circ$. This caused overestimates in $\\tau$ and $\\Gamma$. The previous measurements with all source by Difference Image Analysis (DIA) by MACHO and MOA-I suffer the same bias due to their relatively poor seeing. On the other hand, the measurements with RCG sample by OGLE-II, MACHO and EROS were free from this bias because they seldomected only the events associated to the resolved stars. Thus, the incompleteness both in the number of events and stellar number count cancel out. We estimate $\\tau$ and $\\Gamma$ by correcting this incompleteness. ...

  15. Discovery of the distant cool sub-Neptune mass planet OGLE 2005-BLG-390Lb by microlensing

    Energy Technology Data Exchange (ETDEWEB)

    Beaulieu, J P; Bennett, D P; Fouque, P; Williams, A; Dominik, M; Jorgensen, U G; Kubas, D; Cassan, A; Coutures, C; Greenhill, J; Hill, K; Menzies, J; Sackett, P D; Albrow, M; Brillant, S; Caldwell, J R; Calitz, J J; Cook, K H; Corrales, E; Desort, M; Dieters, S; Dominis, D; Donatowicz, J; Hoffman, M; Kane, S; Marquette, J B; Martin, R; Meintjes, P; Pollard, K; Sahu, K; Vinter, C; Wambsganss, J; Woller, K; Horne, K; Steele, I; Bramich, D M; Burgdorf, M; Snodgrass, C; Bode, M; Udalski, A; Szymanski, M K; Kubiak, M; Wieckowski, T; Pietrzynski, G; Soszynski, I; Szewczyk, O; Wyrzykowski, L; Paczynski, B; Abe, F; Bond, I A; Britton, T R; Gilmore, A C; Hearnshaw, J B; Itow, Y; Kamiya, K; Kilmartin, P M; Korpela, A V; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okada, C; Ohnishi, K; Rattenbury, N J; Sako, T; Sato, S; Sasaki, M; Sekiguchi, T; Sullivan, D J; Tristram, P J; Yock, P M; Yoskioka, T

    2005-11-07

    The favoured theoretical explanation for planetary systems formation is the core-accretion model in which solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars, the most common stars of our Galaxy, this model favours the formation of Earth- to Neptune-mass planets in a few million years with orbital sizes of 1 to 10 AU, which is consistent with the small number of detections of giant planets with M-dwarf host stars. More than 170 extrasolar planets have been discovered so far with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not previously been detected at separations of more than 0.15 AU from normal stars. Here we report the discovery of a 5.5{sub -2.7}{sup +5.5} Earthmass planetary companion at a separation of 2.6{sub -0.6}{sup +1.5}AU from a 0.22{sub -0.11}{sup +0.21} M{sub e} M-dwarf star, which is the lens star for gravitational microlensing event OGLE 2005-BLG-390. This is the lowest mass ever reported for an extrasolar planet orbiting a main sequence star, although the error bars overlap those for the mass of GJ876d. Our detection suggests that such cool, sub-Neptune mass planets may be common than gas giant planets, as predicted by the core accretion theory.

  16. Strong chromatic microlensing in HE0047–1756 and SDSS1155+6346

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, K.; Motta, V. [Instituto de Física y Astronomía, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Playa Ancha, Valparaíso 2360102 (Chile); Mediavilla, E. [Instituto de Astrofísica de Canarias, Avda. Vía Lactea s/n, La Laguna, E-38200 Tenerife (Spain); Falco, E. [Whipple Observatory, Smithsonian Institution, 670 Mt. Hopkins Road, PO Box 6369, Amado, AZ 85645 (United States); Jiménez-Vicente, J. [Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain); Muñoz, J. A., E-mail: karina.rojas@uv.cl, E-mail: veronica.motta@uv.cl, E-mail: emg@iac.es, E-mail: falco@cfa.harvard.edu, E-mail: jjimenez@ugr.es, E-mail: jmunoz@uv.es [Departamento de Astronomía y Astrofísica, Universidad de Valencia, Burjassot, E-46100 Valencia (Spain)

    2014-12-10

    We use spectra of the double-lensed quasars HE0047–1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Lyα line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the continuum of the B image spectrum in SDSS1155+6346 is strongly contaminated by the lens galaxy, and these differences should be considered with caution. Using the flux ratios of the emission lines for image pairs as a baseline to remove macro-magnification and extinction, we have detected strong chromatic microlensing in the continuum measured by CASTLES (www.cfa.harvard.edu/castles/) in both lens systems, with amplitudes 0.09(λ16000) ≲ |Δm| ≲ 0.8(λ5439) for HE0047–1756, and 0.2(λ16000) ≲ |Δm| ≲ 0.8(λ5439) for SDSS1155+6346. Using magnification maps to simulate microlensing and modeling the accretion disk as a Gaussian source (I ∝ exp(–R {sup 2}/2r {sub s}{sup 2})) of size r {sub s} ∝ λ {sup p}, we find r {sub s} = 2.5{sub −1.4}{sup +3.0} √(M/0.3M{sub ⊙}) lt-day and p = 2.3 ± 0.8 at the rest frame for λ = 2045 for HE0047–1756 (log prior) and r {sub s} = 5.5{sub −3.3}{sup +8.2} √(M/0.3M{sub ⊙}) lt-day and p = 1.5 ± 0.6 at the rest frame of λ = 1398 for SDSS1155+6346 (log prior). Contrary to other studied lens systems, the chromaticity detected in HE0047–1756 and SDSS1155+6346 is large enough to fulfill the thin disk prediction. The inferred sizes, however, are very large compared to the predictions of this model, especially in the case of SDSS1155+6346.

  17. Application of Compressive Sensing to Gravitational Microlensing Data and Implications for Miniaturized Space Observatories

    Science.gov (United States)

    Korde-Patel, Asmita (Inventor); Barry, Richard K.; Mohsenin, Tinoosh

    2016-01-01

    Compressive Sensing is a technique for simultaneous acquisition and compression of data that is sparse or can be made sparse in some domain. It is currently under intense development and has been profitably employed for industrial and medical applications. We here describe the use of this technique for the processing of astronomical data. We outline the procedure as applied to exoplanet gravitational microlensing and analyze measurement results and uncertainty values. We describe implications for on-spacecraft data processing for space observatories. Our findings suggest that application of these techniques may yield significant, enabling benefits especially for power and volume-limited space applications such as miniaturized or micro-constellation satellites.

  18. DARK MATTER MASS FRACTION IN LENS GALAXIES: NEW ESTIMATES FROM MICROLENSING

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Vicente, J. [Departamento de Física Teórica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain); Mediavilla, E. [Instituto de Astrofísica de Canarias, Vía Láctea S/N, La Laguna E-38200, Tenerife (Spain); Kochanek, C. S. [Department of Astronomy and the Center for Cosmology and Astroparticle Physics, The Ohio State University, 4055 McPherson Lab, 140 West 18th Avenue, Columbus, OH 43221 (United States); Muñoz, J. A. [Departamento de Astronomía y Astrofísica, Universidad de Valencia, E-46100 Burjassot, Valencia (Spain)

    2015-02-01

    We present a joint estimate of the stellar/dark matter mass fraction in lens galaxies and the average size of the accretion disk of lensed quasars based on microlensing measurements of 27 quasar image pairs seen through 19 lens galaxies. The Bayesian estimate for the fraction of the surface mass density in the form of stars is α = 0.21 ± 0.14 near the Einstein radius of the lenses (∼1-2 effective radii). The estimate for the average accretion disk size is R{sub 1/2}=7.9{sub −2.6}{sup +3.8}√(M/0.3 M{sub ⊙}) light days. The fraction of mass in stars at these radii is significantly larger than previous estimates from microlensing studies assuming quasars were point-like. The corresponding local dark matter fraction of 79% is in good agreement with other estimates based on strong lensing or kinematics. The size of the accretion disk inferred in the present study is slightly larger than previous estimates.

  19. Fabrication of High Performance Microlenses for an Integrated Capillary Channel Electrochromatograph with Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.R.; Warren, M.E.; Sweatt, W.C.; Bailey, C.G.; Matzke, C.M.; Arnold, D.W.; Allerman, A.A.; Carter, T.R.; Asbill, R.E.; Samora, S.

    1999-07-07

    We describe the microfabrication of an extremely compact optical system as a key element in an integrated capillary channel electrochromatograph with fluorescence detection. The optical system consists of a vertical cavity surface-emitting laser (VCSEL), two high performance microlenses and a commercial photodetector. The microlenses are multilevel diffractive optics patterned by electron beam lithography and etched by reactive ion etching in fused silica. The design uses substrate-mode propagation within the fused silica substrate. Two generations of optical subsystems are described. The first generation design has a 6 mm optical length and is integrated directly onto the capillary channel-containing substrate. The second generation design separates the optical system onto its own substrate module and the optical path length is further compressed to 3.5 mm. The first generation design has been tested using direct fluorescence detection with a 750 nm VCSEL pumping a 10{sup {minus}4}M solution of CY-7 dye. The observed signal-to-noise ratio of better than 100:1 demonstrates that the background signal from scattered pump light is low despite the compact size of the optical system and is adequate for system sensitivity requirements.

  20. Microlensing Constraints on Broad Absorption and Emission Line Flows in the Quasar H1413+117

    CERN Document Server

    O'Dowd, Matthew J; Webster, Rachel L; Labrie, Kathleen; Rogers, Joshua

    2015-01-01

    We present new integral field spectroscopy of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet to visible rest-frame spectral range. We observe strong microlensing signatures in lensed image D, and we use this microlensing to simultaneously constrain both the broad emission and broad absorption line gas. By modeling the lens system over the range of probable lensing galaxy redshifts and using on a new argument based on the wavelength-independence of the broad line lensing magnifications, we determine that there is no significant broad line emission from smaller than ~20 light days. We also perform spectral decomposition to derive the intrinsic broad emission line (BEL) and continuum spectrum, subject to BAL absorption. We also reconstruct the intrinsic BAL absorption profile, whose features allow us to constrain outflow kinematics in the context of a disk-wind model. We find a very sharp, blueshifted onset of absorption of 1,500 km/s in both C IV and N V that m...

  1. Completing the Census of Extrasolar Planets in the Milky Way with the Microlensing Planet Finder

    Science.gov (United States)

    Bennett, D. P.; Bond, I.; Cheng, E.; Friedman, S.; Garnavich, P.; Gaudi, B. S.; Gilliland, R.; Gould, A.; Greenhouse, M.; Griest, K.; Kimble, R.; Lunine, J.; Mather, J.; Minniti, D.; Niedner, M.; Paczynski, B.; Peale, S.; Rauscher, B.; Rich, R. M.; Sahu, K.; Tenerelli, D.; Udalski, A.; Woolf, N.; Yock, P.

    2004-12-01

    The Microlensing Planet Finder (MPF) is a proposed Discovery mission that will complete the first census of extrasolar planets with sensitivity to planets like those in our own solar system. MPF will employ a 1.1m aperture telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order to detect extrasolar planets with the gravitational microlensing effect. MPF's sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect Earth-like planets at all separations from 0.7AU to infinity. If the planet:star mass ratios and planetary semi-major axes of our own Solar System are typical, MPF will detect 66 terrestrial planets (Venus/Earth/Mars analogs), 3300 gas giants (Jupiter/Saturn analogs), and 110 ice giants (Uranus/Neptune analogs). Thus, MPF will be able to be able to find analogs to our own Solar System's planets even if planetary systems like ours are not common. MPF's extrasolar planet census will provide critical information needed to understand the formation and frequency of extra solar planetary systems similar to our own.

  2. Capillary-assisted fabrication of biconcave polymeric microlenses from microfluidic ternary emulsion droplets.

    Science.gov (United States)

    Nisisako, Takasi; Ando, Takuya; Hatsuzawa, Takeshi

    2014-12-29

    In this study, a simple capillary-based approach for producing biconcave polymeric microlenses with uniform size and shape from ternary emulsion droplets is presented. Monodisperse ternary emulsion droplets (0.6-4.0 nL) are produced which contain a photocurable segment of an acrylate monomer and two non-curable segments of silicone oil (SO) by using a microfluidic sheath-flowing droplet generator on a glass chip. The curvature radius of the interfaces separating the droplet segments, as well as the droplet size, and production rate can be flexibly varied by changing the flow conditions of the organic and aqueous phases. Subsequently, off-chip suspension photopolymerization yields non-spherical polymeric microparticles with two spherical concave surfaces templated by two SO segments at random positions. By ultraviolet light irradiation of ternary droplets with two SO segments trapped by the interior wall of a cylindrical microcapillary (internal diameter: 130 μm), biconcave microlenses can be produced with two spherical concave surfaces with a common lens axis. The produced lenses are suitable for use as optical diverging lenses.

  3. Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

    CERN Document Server

    Sluse, D

    2014-01-01

    Owing to the advent of large area photometric surveys, the possibility to use broad band photometric data, instead of spectra, to measure the size of the broad line region of active galactic nuclei, has raised a large interest. We describe here a new method using time-delay lensed quasars where one or several images are affected by microlensing due to stars in the lensing galaxy. Because microlensing decreases (or increases) the flux of the continuum compared to the broad line region, it changes the contrast between these two emission components. We show that this effect can be used to effectively disentangle the intrinsic variability of those two regions, offering the opportunity to perform reverberation mapping based on single band photometric data. Based on simulated light curves generated using a damped random walk model of quasar variability, we show that measurement of the size of the broad line region can be achieved using this method, provided one spectrum has been obtained independently during the mo...

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

    CERN Document Server

    Dominik, M; 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; Kane, S

    2008-01-01

    (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 dist...

  5. The different origins of high- and low-ionization broad emission lines revealed by gravitational microlensing in the Einstein cross

    CERN Document Server

    Braibant, Lorraine; Sluse, Dominique; Anguita, Timo

    2016-01-01

    We investigate the kinematics and ionization structure of the broad emission line region of the gravitationally lensed quasar QSO2237+0305 (the Einstein cross) using differential microlensing in the high- and low-ionization broad emission lines. We combine visible and near-infrared spectra of the four images of the lensed quasar and detect a large-amplitude microlensing effect distorting the high-ionization CIV and low-ionization H$\\alpha$ line profiles in image A. While microlensing only magnifies the red wing of the Balmer line, it symmetrically magnifies the wings of the CIV emission line. Given that the same microlensing pattern magnifies both the high- and low-ionization broad emission line regions, these dissimilar distortions of the line profiles suggest that the high- and low-ionization regions are governed by different kinematics. Since this quasar is likely viewed at intermediate inclination, we argue that the differential magnification of the blue and red wings of H$\\alpha$ favors a flattened, viri...

  6. Orbital Motion During Gravitational Lensing Events

    CERN Document Server

    Di Stefano, Rosanne

    2014-01-01

    Gravitational lensing events provide unique opportunities to discover and study planetary systems and binaries. Here we build on previous work to explore the role that orbital motion can play in both identifying and learning more about multiple-mass systems that serve as gravitational lenses. We find that a significant fraction of planet-lens and binary-lens light curves are influenced by orbital motion. Furthermore, the effects of orbital motion extend the range of binaries for which lens multiplicity can be discovered and studied. Orbital motion will play an increasingly important role as observations with sensitive photometry, such as those made by the space missions Kepler, Transiting Exoplanet Survey Satellite, (TESS), and WFIRST discover gravitational lensing events. Similarly, the excellent astrometric measurements made possible by GAIA will allow it to study the effects of orbital motion. Frequent observations, such as those made possible with the Korean Microlensing Telescope Network, KMTNet, will al...

  7. Spectroscopy of MACHO 97-SMC-1: Self-Lensing within the Small Magellanic Cloud

    Science.gov (United States)

    Sahu, Kailash C.; Sahu, M. S.

    1998-12-01

    More than a dozen microlensing events have been detected so far toward the LMC, and two have been detected toward the SMC. If all of the lenses are in the Galactic halo, both the LMC and the SMC events are expected to have similar timescales. However, the first event toward the SMC, MACHO 97-SMC-1, had a timescale of 123 days, which is much larger than the typical timescale for the LMC events. Since the observed timescale of the SMC event would need the mass of the halo lens to be ~3 Msolar, it has been argued earlier that the lens must be within the SMC, which we spectroscopically confirm in this Letter. From optical depth estimates, we first show that the stars within the SMC play a dominant role as gravitational lenses and can fully account for the observed microlensing events, mainly due to its large physical depth. We also show that if the lenses are within the Magellanic Clouds, then the SMC events should be longer in duration than the LMC events, a fact that is consistent with the observations. The timescale of the event implies that the mass of the lens is >~2 Msolar if it is in the Milky Way disk or halo, in which case the lens, if it is a normal star, is expected to be bright and should reveal itself in the spectrum. Here, we present an optical spectrum of MACHO 97-SMC-1 obtained in 1997 May that shows that the source is a main-sequence B star. There is no trace of any contribution from the lens, which suggests that the lens is not in the Milky Way disk or halo but is a low-mass star within the SMC. The other alternative, that the lens could be a black hole in the Galactic halo, cannot be ruled out from the spectrum alone, but this is disfavored by the timescales of the LMC events. It is worth noting here that MACHO SMC-98-1 is the only other observed event toward the SMC. This was a binary lens event for which the caustic crossing timescale as observed by the PLANET, MACHO, EROS, and OGLE collaborations suggests that the lens is within the SMC

  8. Label-Free Nanoscopy with Contact Microlenses: Super-Resolution Mechanisms and Limitations

    CERN Document Server

    Astratov, Vasily N; Brettin, Aaron; Allen, Kenneth W; Maslov, Alexey V; Limberopoulos, Nicholaos I; Walker, Dennis E; Urbas, Augustine M

    2016-01-01

    Despite all the success with developing super-resolution imaging techniques, the Abbe limit poses a severe fundamental restriction on the resolution of far-field imaging systems based on diffraction of light. Imaging with contact microlenses, such as microspheres or microfibers, can increase the resolution by a factor of two beyond the Abbe limit. The theoretical mechanisms of these methods are debated in the literature. In this work, we focus on the recently expressed idea that optical coupling between closely spaced nanoscale objects can lead to the formation of the modes that drastically impact the imaging properties. These coupling effects emerge in nanoplasmonic or nanocavity clusters, photonic molecules, or various arrays under resonant excitation conditions. The coherent nature of imaging processes is key to understanding their physical mechanisms. We used a cluster of point dipoles, as a simple model system, to study and compare the consequences of coherent and incoherent imaging. Using finite differe...

  9. Image restoration for indirectly far-field image using microlenses array integrated with LCD

    Science.gov (United States)

    Yang, Fugui; Wang, Anting; Lei, Dong; Zhe, Cui; Ming, Hai

    2010-10-01

    Image restoration for constructing high-spatial-resolution images in an imaging system which realizes indirectly far-filed imaging by integrating the microlenses array with LCD is reported. We have investigated the indirectly far-field imaging condition where adjacent sampling points contribute the detected signal. Experimental setup with microlens of 500 μm diameter and 8 mm focal length is built to prove this condition by studying performance of image restoration using modified point spread function (PSF). Since any one iterative method is not optimal for all image deblurring problems, some deblurring algorithms including direct deconvolution and iterative deconvolution are applied to our imaging system and we compared the effectiveness of these iterative procedures to choose right one for our use.

  10. Photometric monitoring of the doubly imaged quasar UM673: possible evidence for chromatic microlensing

    CERN Document Server

    Nakos, T; Poels, J; Libbrecht, C; Magain, P; Surdej, J; Manfroid, J; Burud, I; Hjorth, J; Germany, L; Lidman, C; Meylan, G; Pompei, E; Pritchard, J; Saviane, I; Nakos, Th.

    2005-01-01

    We present the results of two-band CCD photometric monitoring of the gravitationally lensed quasar Q 0142-100 (UM 673).The data, obtained at ESO-La Silla with the 1.54 m Danish telescope in the Gunn i-band (October 1998 - September 1999) and in the Johnson V-band (October 1998 to December 2001), were analyzed using three different photometric methods. The light-curves obtained with all methods show variations, with a peak-to-peak amplitude of 0.14 magnitude in $V$. Although it was not possible to measure the time delay between the two lensed QSO images, the brighter component displays possible evidence for microlensing: it becomes bluer as it gets brighter, as expected under the assumption of differential magnification of a quasar accretion disk

  11. MiNDSTEp differential photometry of the gravitationally lensed quasars WFI2033-4723 and HE0047-1756: Microlensing and a new time delay

    CERN Document Server

    Giannini, E; Wambsganß, J; Alsubai, K; Andersen, J M; Anguita, T; Bozza, V; Bramich, D M; Browne, P; Novati, S Calchi; Damerdji, Y; Diehl, C; Dodds, P; Dominik, M; Elyiv, A; Fang, X; Jaimes, R Figuera; Finet, F; Gerner, T; Gu, S; Hardis, S; Harpsøe, K; Hinse, T C; Hornstrup, A; Hundertmark, M; Jessen-Hansen, J; Jørgensen, U G; Juncher, D; Kains, N; Kerins, E; Korhonen, H; Liebig, C; Lund, M N; Lundkvist, M S; Maier, G; Mancini, L; Masi, G; Mathiasen, M; Penny, M; Proft, S; Rabus, M; Rahvar, S; Ricci, D; Scarpetta, G; Sahu, K; Schäfer, S; Schönebeck, F; Skottfelt, J; Snodgrass, C; Southworth, J; Surdej, J; Tregloan-Reed, J; Vilela, C; Wertz, O; Zimmer, F

    2016-01-01

    We present V and R photometry of the gravitationally lensed quasars WFI2033-4723 and HE0047-1756. The data were taken by the MiNDSTEp collaboration with the 1.54 m Danish telescope at the ESO La Silla observatory from 2008 to 2012. Differential photometry has been carried out using the image subtraction method as implemented in the HOTPAnTS package, additionally using GALFIT for quasar photometry. The quasar WFI2033-4723 showed brightness variations of order 0.5 mag in V and R during the campaign. The two lensed components of quasar HE0047-1756 varied by 0.2-0.3 mag within five years. We provide, for the first time, an estimate of the time delay of component B with respect to A of $\\Delta t= 7.6\\pm1.8$ days for this object. We also find evidence for a secular evolution of the magnitude difference between components A and B in both filters, which we explain as due to a long-duration microlensing event. Finally we find that both quasars WFI2033-4723 and HE0047-1756 become bluer when brighter, which is consisten...

  12. MiNDSTEp differential photometry of the gravitationally lensed quasars WFI 2033-4723 and HE 0047-1756: microlensing and a new time delay

    Science.gov (United States)

    Giannini, E.; Schmidt, R. W.; Wambsganss, J.; Alsubai, K.; Andersen, J. M.; Anguita, T.; Bozza, V.; Bramich, D. M.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dodds, P.; Dominik, M.; Elyiv, A.; Fang, X.; Figuera Jaimes, R.; Finet, F.; Gerner, T.; Gu, S.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Juncher, D.; Kains, N.; Kerins, E.; Korhonen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M. S.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Penny, M.; Proft, S.; Rabus, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Sahu, K.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O.; Zimmer, F.

    2017-01-01

    Aims: We present V and R photometry of the gravitationally lensed quasars WFI 2033-4723 and HE 0047-1756. The data were taken by the MiNDSTEp collaboration with the 1.54 m Danish telescope at the ESO La Silla observatory from 2008 to 2012. Methods: Differential photometry has been carried out using the image subtraction method as implemented in the HOTPAnTS package, additionally using GALFIT for quasar photometry. Results: The quasar WFI 2033-4723 showed brightness variations of order 0.5 mag in V and R during the campaign. The two lensed components of quasar HE 0047-1756 varied by 0.2-0.3 mag within five years. We provide, for the first time, an estimate of the time delay of component B with respect to A of Δt = (7.6 ± 1.8) days for this object. We also find evidence for a secular evolution of the magnitude difference between components A and B in both filters, which we explain as due to a long-duration microlensing event. Finally we find that both quasars WFI 2033-4723 and HE 0047-1756 become bluer when brighter, which is consistent with previous studies. Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla observatory.

  13. Using graphical and pictorial representations to teach introductory astronomy students about the detection of extrasolar planets via gravitational microlensing

    Science.gov (United States)

    Wallace, Colin S.; Chambers, Timothy G.; Prather, Edward E.; Brissenden, Gina

    2016-05-01

    The detection and study of extrasolar planets is an exciting and thriving field in modern astrophysics and an increasingly popular topic in introductory astronomy courses. One detection method relies on searching for stars whose light has been gravitationally microlensed by an extrasolar planet. In order to facilitate instructors' abilities to bring this interesting mix of general relativity and extrasolar planet detection into the introductory astronomy classroom, we have developed a new Lecture-Tutorial called "Detecting Exoplanets with Gravitational Microlensing." In this paper, we describe how this new Lecture-Tutorial's representations of astrophysical phenomena, which we selected and created based on theoretically motivated considerations of their pedagogical affordances, are used to help introductory astronomy students develop more expert-like reasoning abilities.

  14. Using graphical and pictorial representations to teach introductory astronomy students about the detection of extrasolar planets via gravitational microlensing

    CERN Document Server

    Wallace, Colin S; Prather, Edward E; Brissenden, Gina

    2016-01-01

    The detection and study of extrasolar planets is an exciting and thriving field in modern astrophysics, and an increasingly popular topic in introductory astronomy courses. One detection method relies on searching for stars whose light has been gravitationally microlensed by an extrasolar planet. In order to facilitate instructors' abilities to bring this interesting mix of general relativity and extrasolar planet detection into the introductory astronomy classroom, we have developed a new Lecture-Tutorial, "Detecting Exoplanets with Gravitational Microlensing." In this paper, we describe how this new Lecture-Tutorial's representations of astrophysical phenomena, which we selected and created based on theoretically motivated considerations of their pedagogical affordances, are used to help introductory astronomy students develop more expert-like reasoning abilities.

  15. Elastomeric inverse moulding and vacuum casting process characterization for the fabrication of arrays of concave refractive microlenses

    Science.gov (United States)

    Desmet, L.; Van Overmeire, S.; Van Erps, J.; Ottevaere, H.; Debaes, C.; Thienpont, H.

    2007-01-01

    We present a complete and precise quantitative characterization of the different process steps used in an elastomeric inverse moulding and vacuum casting technique. We use the latter replication technique to fabricate concave replicas from an array of convex thermal reflow microlenses. During the inverse elastomeric moulding we obtain a secondary silicone mould of the original silicone mould in which the master component is embedded. Using vacuum casting, we are then able to cast out of the second mould several optical transparent poly-urethane arrays of concave refractive microlenses. We select ten particular representative microlenses on the original, the silicone moulds and replica sample and quantitatively characterize and statistically compare them during the various fabrication steps. For this purpose, we use several state-of-the-art and ultra-precise characterization tools such as a stereo microscope, a stylus surface profilometer, a non-contact optical profilometer, a Mach-Zehnder interferometer, a Twyman-Green interferometer and an atomic force microscope to compare various microlens parameters such as the lens height, the diameter, the paraxial focal length, the radius of curvature, the Strehl ratio, the peak-to-valley and the root-mean-square wave aberrations and the surface roughness. When appropriate, the microlens parameter under test is measured with several different measuring tools to check for consistency in the measurement data. Although none of the lens samples shows diffraction-limited performance, we prove that the obtained replicated arrays of concave microlenses exhibit sufficiently low surface roughness and sufficiently high lens quality for various imaging applications.

  16. Microlensing of Sub-parsec Massive Binary Black Holes in Lensed QSOs: Light Curves and Size-Wavelength Relation

    CERN Document Server

    Yan, Chang-Shuo; Yu, Qingjuan; Mao, Shude; Wambsganss, Joachim

    2014-01-01

    Sub-parsec binary massive black holes (BBHs) are long anticipated to exist in many QSOs but remain observationally elusive. In this paper, we propose a novel method to probe sub-parsec BBHs through microlensing of lensed QSOs. If a QSO hosts a sub-parsec BBH in its center, it is expected that the BBH is surrounded by a circum-binary disk, each component of the BBH is surrounded by a small accretion disk, and a gap is opened by the secondary component in between the circum-binary disk and the two small disks. Assuming such a BBH structure, we generate mock microlensing light curves for some QSO systems that host BBHs with typical physical parameters. We show that microlensing light curves of a BBH QSO system at the infrared-optical-UV bands can be significantly different from those of corresponding QSO system with a single massive black hole (MBH), mainly because of the existence of the gap and the rotation of the BBH (and its associated small disks) around the center of mass. We estimate the half-light radii ...

  17. MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand

    CERN Document Server

    Sako, T; Sasaki, M; Okajima, K; Abe, F; Bond, I A; Hearnshaw, J B; Itow, Y; Kamiya, K; Kilmartin, P M; Masuda, K; Matsubara, Y; Muraki, Y; Rattenbury, N J; Sullivan, D J; Sumi, T; Tristram, P; Yanagisawa, T; Yock, P C M

    2008-01-01

    We have developed a wide-field mosaic CCD camera, MOA-cam3, mounted at the prime focus of the Microlensing Observations in Astrophysics (MOA) 1.8-m telescope. The camera consists of ten E2V CCD4482 chips, each having 2kx4k pixels, and covers a 2.2 deg^2 field of view with a single exposure. The optical system is well optimized to realize uniform image quality over this wide field. The chips are constantly cooled by a cryocooler at -80C, at which temperature dark current noise is negligible for a typical 1-3 minute exposure. The CCD output charge is converted to a 16-bit digital signal by the GenIII system (Astronomical Research Cameras Inc.) and readout is within 25 seconds. Readout noise of 2--3 ADU (rms) is also negligible. We prepared a wide-band red filter for an effective microlensing survey and also Bessell V, I filters for standard astronomical studies. Microlensing studies have entered into a new era, which requires more statistics, and more rapid alerts to catch exotic light curves. Our new system is...

  18. Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates

    Science.gov (United States)

    More, Anupreeta; Suyu, Sherry H.; Oguri, Masamune; More, Surhud; Lee, Chien-Hsiu

    2017-02-01

    We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well known, accurately measured time delays of the multiple images could provide tight constraints on the Hubble constant. According to our lens mass models constrained by the Hubble Space Telescope F814W image, we expect the maximum relative time delay to be less than a day, which is consistent with the maximum of 100 hr reported by Goobar et al. but places a stringent upper limit. Furthermore, the fluxes of most of the supernova images depart from expected values suggesting that they are affected by microlensing. The microlensing timescales are small enough that they may pose significant problems to measure the time delays reliably. Our lensing rate calculation indicates that the occurrence of a lensed SN in iPTF is likely. However, the observed total magnification of iPTF16geu is larger than expected, given its redshift. This may be a further indication of ongoing microlensing in this system.

  19. POINT-AGAPE Pixel Lensing Survey of M31 Evidence for a MACHO contribution to Galactic Halos

    CERN Document Server

    Novati, S C; An, J; Baillon, Paul; Belokurov, V; Carr, B J; Creze, M; Evans, N W; Giraud-Héraud, Yannick; Gould, A; Jetzer, P; Kaplan, J; Kerins, E; Hewett, P C; Smartt, S J; Stalin, C S; Tsapras, Y; Weston, M J; Jetzer, Ph.

    2005-01-01

    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.

  20. Fabrication of polymer-based reflowed microlenses on optical fibre with control of focal length using differential coating technique

    Indian Academy of Sciences (India)

    Mohammed Ashraf; Franck Chollet; Murukeshan Matham; Chun Yang

    2009-08-01

    Thermal reflow of polymer to generate spherical profile has been used to fabricate microlenses in this paper. A simple model based on the volume conservation (before and after reflow) and geometrical consideration of lens profile, shows that the focal length of the microlens produced by reflow technique is a function of the initial geometry of microcylinders, i.e. diameter and thickness. This relationship of focal length with diameter and thickness is used as a basis to control focal length. A simple spin coating technique on dual surface is used to achieve differential thickness, to control the focal length of microlenses produced on the same substrate. A biomedical application of such combination of microlenses is endoscopy where the lenses of varying diameter and equal focal length are needed on top of optical fibre bundles to provide independent function of illumination and imaging. This paper incorporates the differential thickness technique to show a micro fabrication process to produce the polymer reflowed microlenses, with a control of focal length based on thickness. The design also helps to integrate these microlenses on top an optical fibre with accurate alignment.

  1. MOA-II Galactic microlensing constraints: the inner Milky Way has a low dark matter fraction and a near maximal disc

    Science.gov (United States)

    Wegg, Christopher; Gerhard, Ortwin; Portail, Matthieu

    2016-11-01

    Microlensing provides a unique tool to break the stellar to dark matter degeneracy in the inner Milky Way. We combine N-body dynamical models fitted to the Milky Way's Boxy/Peanut bulge with exponential disc models outside this, and compute the microlensing properties. Considering the range of models consistent with the revised MOA-II data, we find low dark matter fractions in the inner Galaxy: at the peak of their stellar rotation curve a fraction fv = (0.88 ± 0.07) of the circular velocity is baryonic (at 1σ, fv > 0.72 at 2σ). These results are in agreement with constraints from the EROS-II microlensing survey of brighter resolved stars, where we find fv = (0.9 ± 0.1) at 1σ. Our fiducial model of a disc with scale length 2.6 kpc, and a bulge with a low dark matter fraction of 12 per cent, agrees with both the revised MOA-II and EROS-II microlensing data. The required baryonic fractions, and the resultant low contribution from dark matter, are consistent with the NFW profiles produced by dissipationless cosmological simulations in Milky Way mass galaxies. They are also consistent with recent prescriptions for the mild adiabatic contraction of Milky Way mass haloes without the need for strong feedback, but there is some tension with recent measurements of the local dark matter density. Microlensing optical depths from the larger OGLE-III sample could improve these constraints further when available.

  2. Beyond the Wobbles: Teaching Students About Detecting Planets with the Transit and Gravitational Microlensing Methods

    Science.gov (United States)

    Prather, Edward E.; Wallace, Colin Scott; Chambers, Timothy G.; Brissenden, Gina; Traub, Wesley A.; Greene, W. M.; Biferno, Anya A.; Rodriguez, Joshua

    2015-01-01

    Members of the Center for Astronomy Education (CAE) at the University of Arizona's Steward Observatory in collaboration with JPL scientists, visualization experts, and education and public outreach professionals with the Exoplanet Exploration Program (ExEP) have recently completed classroom field-testing of a new suite of educational materials to help learners better understand how extrasolar planets are detected using the transit and gravitational microlensing techniques. This collaboration has created a set of evidence-based Think-Pair-Share questions, Lecture-Tutorials, animations, presentation slides, and instrucotrs guide that can be used together or separately to actively engage learners in reasoning about the data and scientific representations associated with these exciting new extrasolar planet detection methods. In this talk we present several of the conceptually challenging collaborative learning tasks that students encounter with this new suite of educational materials and some of the assessment questions we are using to assess the efficacy of their use in general education, college-level astronomy courses.

  3. Integral field spectroscopy of four lensed quasars: analysis of their neighborhood and evidence for microlensing

    CERN Document Server

    Anguita, T; Yonehara, A; Wambsganss, J; Kneib, J -P; Covone, G; Alloin, D

    2008-01-01

    CONTEXT: Gravitationally lensed quasars constitute an independent tool to derive H0 through time-delays; they offer as well the opportunity to study the mass distribution and interstellar medium of their lensing galaxies and, through microlensing they also allow one to study details of the emitting source. AIMS: For such studies, one needs to have an excellent knowledge of the close environment of the lensed images in order to model the lensing potential: this means observational data over a large field-of-view and spectroscopy at high spatial resolution. METHODS: We present VIMOS integral field observations around four lensed quasars: HE 0230-2130, RX J0911.4+0551, H 1413+117 and B 1359+154. Using the low, medium and high resolution modes, we study the quasar images and the quasar environments, as well as provide a detailed report of the data reduction. RESULTS: Comparison between the quasar spectra of the different images reveals differences for HE 0230-2130, RX J0911.4+0551 and H 1413+117: flux ratios betw...

  4. On the age of Galactic bulge microlensed dwarf and subgiant stars

    CERN Document Server

    Valle, G; Moroni, P G Prada; Degl'Innocenti, S

    2015-01-01

    Recent results by Bensby and collaborators on the ages of microlensed stars in the Galactic bulge have challenged the picture of an exclusively old stellar population. However, these age estimates have not been independently confirmed. In this paper we verify these results by means of a grid-based method and quantify the systematic biases that might be induced by some assumptions adopted to compute stellar models. We explore the impact of increasing the initial helium abundance, neglecting the element microscopic diffusion, and changing the mixing-length calibration in theoretical stellar track computations. We adopt the SCEPtER pipeline with a novel stellar model grid for metallicities [Fe/H] from -2.00 to 0.55 dex, and masses in the range [0.60; 1.60] Msun from the ZAMS to the helium flash at the red giant branch tip. We show for the considered evolutionary phases that our technique provides unbiased age estimates. Our age results are in good agreement with Bensby and collaborators findings and show 16 star...

  5. Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

    Science.gov (United States)

    Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

    2016-04-15

    A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

  6. Further Evidence that Quasar X-Ray Emitting Regions Are Compact: X-Ray and Optical Microlensing in the Lensed Quasar Q J0158-4325

    OpenAIRE

    Morgan, Christopher W.; Hainline, Laura J.; Chen, Bin; Tewes, Malte; Kochanek, Christopher S.; Dai, Xinyu; Kozlowski, Szymon; Blackburne, Jeffrey A.; Mosquera, Ana M.; Chartas, George; Courbin, Frederic; Meylan, Georges

    2012-01-01

    We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly-imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microlensing variability for which this system is known has historically precluded a time delay measurement by conventional methods. We attempt to circumvent this limitation by application of a Monte Carlo microlensing analysis technique, but we are only able to prove that the delay must have the expected sign (image A lea...

  7. Microlensing of Sub-parsec Massive Binary Black Holes in Lensed QSOs: Light Curves and Size-Wavelength Relation

    Science.gov (United States)

    Yan, Chang-Shuo; Lu, Youjun; Yu, Qingjuan; Mao, Shude; Wambsganss, Joachim

    2014-04-01

    Sub-parsec binary massive black holes (BBHs) have long been thought to exist in many QSOs but remain observationally elusive. In this paper, we propose a novel method to probe sub-parsec BBHs through microlensing of lensed QSOs. If a QSO hosts a sub-parsec BBH in its center, it is expected that the BBH is surrounded by a circumbinary disk, each component of the BBH is surrounded by a small accretion disk, and a gap is opened by the secondary component in between the circumbinary disk and the two small disks. Assuming such a BBH structure, we generate mock microlensing light curves for some QSO systems that host BBHs with typical physical parameters. We show that microlensing light curves of a BBH QSO system at the infrared-optical-UV bands can be significantly different from those of corresponding QSO system with a single massive black hole (MBH), mainly because of the existence of the gap and the rotation of the BBH (and its associated small disks) around the center of mass. We estimate the half-light radii of the emission region at different wavelengths from mock light curves and find that the obtained half-light radius versus wavelength relations of BBH QSO systems can be much flatter than those of single MBH QSO systems at a wavelength range determined by the BBH parameters, such as the total mass, mass ratio, separation, accretion rates, etc. The difference is primarily due to the existence of the gap. Such unique features on the light curves and half-light radius-wavelength relations of BBH QSO systems can be used to select and probe sub-parsec BBHs in a large number of lensed QSOs to be discovered by current and future surveys, including the Panoramic Survey Telescope and Rapid Response System, the Large Synoptic Survey telescope, and Euclid.

  8. Single nucleotide polymorphism detection using gold nanoprobes and bio-microfluidic platform with embedded microlenses.

    Science.gov (United States)

    Bernacka-Wojcik, Iwona; Águas, Hugo; Carlos, Fabio Ferreira; Lopes, Paulo; Wojcik, Pawel Jerzy; Costa, Mafalda Nascimento; Veigas, Bruno; Igreja, Rui; Fortunato, Elvira; Baptista, Pedro Viana; Martins, Rodrigo

    2015-06-01

    The use of microfluidics platforms combined with the optimal optical properties of gold nanoparticles has found plenty of application in molecular biosensing. This paper describes a bio-microfluidic platform coupled to a non-cross-linking colorimetric gold nanoprobe assay to detect a single nucleotide polymorphism associated with increased risk of obesity fat-mass and obesity-associated (FTO) rs9939609 (Carlos et al., 2014). The system enabled significant discrimination between positive and negative assays using a target DNA concentration of 5 ng/µL below the limit of detection of the conventionally used microplate reader (i.e., 15 ng/µL) with 10 times lower solution volume (i.e., 3 µL). A set of optimization of our previously reported bio-microfluidic platform (Bernacka-Wojcik et al., 2013) resulted in a 160% improvement of colorimetric analysis results. Incorporation of planar microlenses increased 6 times signal-to-loss ratio reaching the output optical fiber improving by 34% the colorimetric analysis of gold nanoparticles, while the implementation of an optoelectronic acquisition system yielded increased accuracy and reduced noise. The microfluidic chip was also integrated with a miniature fiber spectrometer to analyze the assays' colorimetric changes and also the LEDs transmission spectra when illuminating through various solutions. Furthermore, by coupling an optical microscope to a digital camera with a long exposure time (30 s), we could visualise the different scatter intensities of gold nanoparticles within channels following salt addition. These intensities correlate well to the expected difference in aggregation between FTO positive (none to small aggregates) and negative samples (large aggregates).

  9. Event Management

    OpenAIRE

    Havlenová, Tereza

    2016-01-01

    Event is an experience that is perceived by all the senses. Event management is a process involving the various activities that are assigned to staffers. Organizing special events became an individual field. If the manager understand the events as a communication platform gets into the hands of a modern, multifunctional and very impressive tool. The procedure to implement a successful event in a particular area is part of this work. The first part explains the issues of event management on th...

  10. Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, II: The Frequency of Planets Orbiting M Dwarfs

    CERN Document Server

    Clanton, Christian

    2014-01-01

    In contrast to radial velocity surveys, results from microlensing surveys indicate that giant planets with masses greater than the critical mass for core accretion ($\\sim 0.1~M_{\\rm Jup}$) are relatively common around low-mass stars. Using the methodology developed in the first paper, we predict the sensitivity of M-dwarf radial velocity (RV) surveys to analogs of the population of planets inferred by microlensing. We find that RV surveys should detect a handful of super-Jovian ($>M_{\\rm Jup}$) planets at the longest periods being probed. These planets are indeed found by RV surveys, implying that the demographic constraints inferred from these two methods are consistent. We combine the results from both methods to estimate planet frequencies spanning wide regions of parameter space. We find that the frequency of Jupiters and super-Jupiters ($1\\lesssim m_p\\sin{i}/M_{\\rm Jup}\\lesssim 13$) with periods $1\\leq P/{\\rm days}\\leq 10^4$ is $f_{\\rm J}=0.029^{+0.013}_{-0.015}$, a median factor of 4.3 ($1.5-14$ at 95% ...

  11. The Galactic Exoplanet Survey Telescope A Proposed Space-Based Microlensing Survey for Terrestrial Extra-Solar Planets

    CERN Document Server

    Bennett, D P; Bennett, David P.; Rhie, Sun Hong

    2000-01-01

    We present a conceptual design for a space based Galactic Exoplanet SurveyTelescope (GEST) which will use the gravitational microlensing technique todetect extra solar planets with masses as low as that of Mars at allseparations >~ 1 AU. The microlensing data would be collected by a diffractionlimited, wide field imaging telescope of ~ 1.5m aperture equipped with a largearray of red-optimized CCD detectors. Such a system would be able to monitor$\\sim 2\\times 10^8$ stars in $\\sim 6$ square degrees of the Galactic bulge atintervals of 20-30 minutes, and it would observe $\\sim 12000$ microlensingevents in three bulge seasons. If planetary systems like our own are common,GEST should be able to detect $\\sim 5000$ planets over a 2.5 year lifetime. Ifgas giants like Jupiter and Saturn are rare, then GEST would detect $\\sim 1300$planets in a 2.5 year mission if we assume that most planetary systems aredominated by planets of about Neptune's' mass. Such a mission would alsodiscover $\\sim 100$ planets of an Earth mass ...

  12. Interpreting the strongly lensed supernova iPTF16geu: time delay predictions, microlensing, and lensing rates

    CERN Document Server

    More, Anupreeta; Oguri, Masamune; More, Surhud; Lee, Chien-Hsiu

    2016-01-01

    We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well-known, accurately measured time delays of the multiple images could provide tight constraints on the Hubble constant. According to our lens mass models constrained by the {\\it Hubble Space Telescope} F814W image, we expect the maximum relative time delay to be less than a day, which is consistent with the maximum of 100 hours reported by Goobar et al. but places a stringent upper limit. Furthermore, the fluxes of most of the supernova images depart from expected values suggesting that they are affected by microlensing. The microlensing timescales are small enough that they may pose significant problems to measure the time delays reliably. Our lensing rate calculation indicates that the occurrence of a lensed SN in iPTF is likely. Howev...

  13. Time Delay and Accretion Disk Size Measurements in the Lensed Quasar SBS 0909+532 from Multiwavelength Microlensing Analysis

    CERN Document Server

    Hainline, Laura J; MacLeod, Chelsea L; Landaal, Zachary D; Kochanek, C S; Harris, Hugh C; Tilleman, Trudy; Goicoechea, L J; Shalyapin, V N; Falco, Emilio E

    2013-01-01

    We present three complete seasons and two half-seasons of SDSS r-band photometry of the gravitationally lensed quasar SBS 0909+532 from the U.S. Naval Observatory, as well as two seasons each of SDSS g-band and r-band monitoring from the Liverpool Robotic Telescope. Using Monte Carlo simulations to simultaneously measure the system's time delay and model the r-band microlensing variability, we confirm and significantly refine the precision of the system's time delay to \\Delta t_{AB} = 50^{+2}_{-4} days, where the stated uncertainties represent the bounds of the formal 1\\sigma\\ confidence interval. There may be a conflict between the time delay measurement and a lens consisting of a single galaxy. While models based on the Hubble Space Telescope astrometry and a relatively compact stellar distribution can reproduce the observed delay, the models have somewhat less dark matter than we would typically expect. We also carry out a joint analysis of the microlensing variability in the r- and g-bands to constrain th...

  14. Search for black matter through the detection of gravitational micro-lenses in differential photometry; Recherche de matiere noire galactique par detection de microlentilles gravitationnelles en photometrie differentielle

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, L

    2003-09-01

    The nature of dark matter is an open question. The search for gravitational microlensing effects is an interesting tool because this effect is strongly dependent on the mass of objects whether they are luminous or not, however this detection method is only sensitive to compact forms of dark matter (MACHOS - massive astronomical halo compact objects), and as a consequence no-baryonic matter like neutrinos or WIMPS (weakly interacting massive particles) can not be detected this way. In the first chapter the author reviews the plausible candidates to black matter. The use of the microlensing effect as a probe of the galactic halo is presented in the second chapter. The third chapter is dedicated to the series of experiments worldwide that focus on the detection of MACHOS. In the fourth chapter the author shows how the DIA (difference image analysis) method may be promising in the study of gravitational microlensing effects. The main part of this work has been the use of the DIA method to process five-year data set collected by the Eros experiment in the small Magellanic cloud (SMC). The data processing line and the results are presented in the fifth and sixth chapters. The results are consistent with previous results given by Eros and they confirm the disparity of the durations of micro-lenses detected in the large and small Magellanic clouds. (A.C.)

  15. MOA-II Galactic Microlensing Constraints: The Inner Milky Way has a Low Dark Matter Fraction and a Near Maximal Disk

    CERN Document Server

    Wegg, Christopher; Portail, Matthieu

    2016-01-01

    Microlensing provides a unique tool to break the stellar to dark matter degeneracy in the inner Milky Way. We combine N-body dynamical models fitted to the Milky Way's Boxy/Peanut bulge with exponential disk models outside this, and compute the microlensing properties. Considering the range of models consistent with the revised MOA-II data, we find low dark matter fractions in the inner Galaxy: at the peak of their stellar rotation curve a fraction $f_v=(0.88\\pm0.07)$ of the circular velocity is baryonic (at $1\\sigma$, $f_v > 0.72$ at $2\\sigma$). These results are in agreement with constraints from the EROS-II microlensing survey of brighter resolved stars, where we find $f_v=(0.9\\pm0.1)$ at $1\\sigma$. Our fiducial model of a disk with scale length 2.6kpc, and a bulge with a low dark matter fraction of 12%, agrees with both the revised MOA-II and EROS-II microlensing data. The required baryonic fractions, and the resultant low contribution from dark matter, are consistent with the NFW profiles produced by dis...

  16. Variability of GeV gamma-ray emission in QSO B0218+357 due to microlensing on intermediate size structures

    Science.gov (United States)

    Sitarek, J.; Bednarek, W.

    2016-06-01

    Strong gravitational lensing leads to an occurrence of multiple images, with different magnifications, of a lensed source. Those magnifications can in turn be modified by microlensing on smaller mass scales within the lens. Recently, measurements of the changes in the magnification ratio of the individual images have been proposed as a powerful tool for estimation of the size and velocity of the emission region in the lensed source. The changes of the magnification ratios in blazars PKS1830-211 and QSO B0218+357, if interpreted as caused by a microlensing on individual stars, put strong constraints on those two variables. These constraints are difficult to accommodate with the current models of gamma-ray emission in blazars. In this paper we study if similar changes in the magnification ratio can be caused by microlensing on intermediate size structures in the lensing galaxy. We investigate in details three classes of possible lenses: globular clusters (GCs), open clusters (OCs) and giant molecular clouds (GMCs). We apply this scenario to the case of QSO B0218+357. Our numerical simulations show that changes in magnifications with similar time-scales can be obtained for relativistically moving emission regions with sizes up to 0.01 pc in the case of microlensing on the cores of GCs or clumps in GMCs. From the density of such structures in spiral galaxies we estimate however that lensing in GMCs would be more common.

  17. Event marketing

    OpenAIRE

    Novotná, Michaela

    2008-01-01

    This study aims to analyze event-marketing activities of the small firm and propose new events. At first the theoretical part describes marketing and communication mix and then especially planning and development of event marketing campaign. Research data were collected by the method of survey to propose the new events. Randomly selected customers were asked to fill the questionnaire. Its results were integrated into the proposal of the new events. The interview was realized with the owner of...

  18. The Demographics of Exoplanetary Companions to M Dwarfs: Synthesizing Results from Microlensing, Radial Velocity, and Direct Imaging Surveys

    Science.gov (United States)

    Clanton, Christian Dwain

    Over the past 20 years, we have learned that exoplanets are ubiquitous throughout our Galaxy and show a diverse set of demographics, yet there is much work to be done to understand this diversity. Determining the distributions of the fundamental properties of exoplanets will provide vital clues regarding their formation and evolution. This is a difficult task, as exoplanet surveys are not uniformly sensitive to the full range of planet parameter space. Various observational biases and selection effects intrinsic to each of the different discovery techniques constrain the types of planets to which they are sensitive. Herein, I record a collection of the first studies to develop and apply the methodology of synthesizing results from multiple detection techniques to construct a statistically-complete census of planetary companions to M dwarfs that samples a wide region of their parameter space. I present a robust comparison of exoplanet discoveries from microlensing and radial velocity (RV) surveys of M dwarfs which infer giant planet frequencies that differ by more than an order of magnitude and are, prima facie, in direct conflict. I demonstrate that current, state-of-the-art RV surveys are capable of detecting only the high-mass tail of the population of planets beyond the ice line inferred by microlensing studies, engendering a large, apparent difference in giant planet frequency. This comparison further establishes that results from these types of surveys are, in fact, consistent over the region of parameter space wherein their sensitivities overlap. A synthesis of results from microlensing and RV surveys yields planet occurrence rates for M dwarfs that span several orders of magnitude in mass and orbital period. On average, each M dwarf hosts about two planets, and while Jupiter and super-Jupiter companions are relatively rare ( 3%), gas giants, in general, are quite common ( 15%). These occurrence rates are significantly lower than those inferred around FGK

  19. TIME DELAY AND ACCRETION DISK SIZE MEASUREMENTS IN THE LENSED QUASAR SBS 0909+532 FROM MULTIWAVELENGTH MICROLENSING ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Hainline, Laura J.; Morgan, Christopher W.; MacLeod, Chelsea L.; Landaal, Zachary D. [Department of Physics, United States Naval Academy, 572C Holloway Rd, Annapolis, MD 21402 (United States); Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 West 18th Ave, Columbus, OH 43210 (United States); Harris, Hugh C.; Tilleman, Trudy [United States Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Goicoechea, L. J.; Shalyapin, V. N. [Facultad de Ciencias, Universidad de Cantabria, Avda. de Los Castros s/n, E-39005 Santander (Spain); Falco, Emilio E., E-mail: hainline@usna.edu, E-mail: cmorgan@usna.edu, E-mail: macleod@usna.edu, E-mail: m123894@usna.edu, E-mail: ckochanek@astronomy.ohio-state.edu, E-mail: hch@nofs.navy.mil, E-mail: trudy@nofs.navy.mil, E-mail: goicol@unican.es, E-mail: vshal@ukr.net, E-mail: falco@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States)

    2013-09-01

    We present three complete seasons and two half-seasons of Sloan Digital Sky Survey (SDSS) r-band photometry of the gravitationally lensed quasar SBS 0909+532 from the U.S. Naval Observatory, as well as two seasons each of SDSS g-band and r-band monitoring from the Liverpool Robotic Telescope. Using Monte Carlo simulations to simultaneously measure the system's time delay and model the r-band microlensing variability, we confirm and significantly refine the precision of the system's time delay to {Delta}t{sub AB} = 50{sub -4}{sup +2} days, where the stated uncertainties represent the bounds of the formal 1{sigma} confidence interval. There may be a conflict between the time delay measurement and a lens consisting of a single galaxy. While models based on the Hubble Space Telescope astrometry and a relatively compact stellar distribution can reproduce the observed delay, the models have somewhat less dark matter than we would typically expect. We also carry out a joint analysis of the microlensing variability in the r and g bands to constrain the size of the quasar's continuum source at these wavelengths, obtaining log {l_brace}(r{sub s,r}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 15.3 {+-} 0.3 and log {l_brace}(r{sub s,g}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 14.8 {+-} 0.9, respectively. Our current results do not formally constrain the temperature profile of the accretion disk but are consistent with the expectations of standard thin disk theory.

  20. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics. We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...

  1. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics.We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...

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

    CERN Document Server

    Dominik, M; 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; Wyrzykowski, L

    2008-01-01

    (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 l...

  3. Further Evidence that Quasar X-Ray Emitting Regions Are Compact: X-Ray and Optical Microlensing in the Lensed Quasar Q J0158-4325

    CERN Document Server

    Morgan, Christopher W; Chen, Bin; Tewes, Malte; Kochanek, Christopher S; Dai, Xinyu; Kozlowski, Szymon; Blackburne, Jeffrey A; Mosquera, Ana M; Chartas, George; Courbin, Frederic; Meylan, Georges

    2012-01-01

    We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly-imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microlensing variability for which this system is known has historically precluded a time delay measurement by conventional methods. We attempt to circumvent this limitation by application of a Monte Carlo microlensing analysis technique, but we are only able to prove that the delay must have the expected sign (image A leads image B). Despite our failure to robustly measure the time delay, we successfully model the microlensing at optical and X-ray wavelengths to find a half light radius for soft X-ray emission log(r_{1/2,X,soft}/cm) = 14.3^{+0.4}_{-0.5}, an upper limit on the half-light radius for hard X-ray emission log(r_{1/2,X,hard}/cm) <= 14.6 and a refined estimate of the inclination-corrected scale radius of the optical R-band (rest frame 3100 Angstrom) continuum emission region of log(r_s/cm) = 15.6+-0.3.

  4. Variability of GeV gamma-ray emission in QSO B0218+357 due to microlensing on intermediate size structures

    CERN Document Server

    Sitarek, Julian

    2016-01-01

    Strong gravitational lensing leads to an occurrence of multiple images, with different magnifications, of a lensed source. Those magnifications can in turn be modified by microlensing on smaller mass scales within the lens. Recently, measurements of the changes in the magnification ratio of the individual images have been proposed as a powerful tool for estimation of the size and velocity of the emission region in the lensed source. The changes of the magnification ratios in blazars PKS1830-211 and QSO B0218+357, if interpreted as caused by a microlensing on individual stars, put strong constraints on those two variables. These constraints are difficult to accommodate with the current models of gamma-ray emission in blazars. In this paper we study if similar changes in the magnification ratio can be caused by microlensing on intermediate size structures in the lensing galaxy. We investigate in details three classes of possible lenses: globular clusters (GC), open clusters (OC) and giant molecular clouds (GMC)...

  5. Microlensing discovery of a tight, low-mass-ratio planetary-mass object around an old field brown dwarf

    Energy Technology Data Exchange (ETDEWEB)

    Han, C.; Jung, Y. K. [Department of Physics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Skowron, J.; Kozłowski, S.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Gaudi, B. S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bennett, D. P. [University of Notre Dame, Department of Physics, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Goleta, CA 93117 (United States); Abe, F. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bond, I. A. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand); Collaboration: OGLE Collaboration; MOA Collaboration; μFUN Collaboration; RoboNet Collaboration; and others

    2013-11-20

    Observations of accretion disks around young brown dwarfs (BDs) have led to the speculation that they may form planetary systems similar to normal stars. While there have been several detections of planetary-mass objects around BDs (2MASS 1207-3932 and 2MASS 0441-2301), these companions have relatively large mass ratios and projected separations, suggesting that they formed in a manner analogous to stellar binaries. We present the discovery of a planetary-mass object orbiting a field BD via gravitational microlensing, OGLE-2012-BLG-0358Lb. The system is a low secondary/primary mass ratio (0.080 ± 0.001), relatively tightly separated (∼0.87 AU) binary composed of a planetary-mass object with 1.9 ± 0.2 Jupiter masses orbiting a BD with a mass 0.022 M {sub ☉}. The relatively small mass ratio and separation suggest that the companion may have formed in a protoplanetary disk around the BD host in a manner analogous to planets.

  6. Binary Source Event Masquerading as Planet: A New Manifestation of the Binary-Source Degeneracy

    CERN Document Server

    Jung, Y K; Yee, J C; Sumi, T; Gould, A; Han, C; Albrow, M D; Lee, C -U; Kim, S -L; Chung, S -J; Hwang, K -H; Ryu, Y -H; Shin, I -G; Zhu, W; Cha, S -M; Kim, D -J; Lee, Y; Park, B -G; Pogge, R W; Pietrukowicz, P; Kozlowski, S; Poleski, R; Skowron, J; Mroz, P; Szymanski, M K; Soszynski, I; Pawlak, M; Ulaczyk, K; Abe, F; Bennett, D P; Asakura, Y; Bhattacharya, 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; Oyokawa, H; Sharan, A; Sullivan, D J; Suzuki, D; Tristram, P J; Yamada, T; Yamada, T; Yonehara, A

    2016-01-01

    We present the analysis of the microlensing event OGLE-2016-BLG-0733, which introduces a new type of degeneracy between binary source and planetary perturbations. The light curve of the event exhibits a long-term asymmetric perturbation that would appear to be due to a planet. From detailed analysis of the light curve, however, we find that the perturbation originates from the binarity of the source rather than the lens. This result demonstrates that binary sources with roughly equal-luminosity components can mimic long-term perturbations induced by planets with projected separations near the Einstein ring. The result also signifies the importance of considering various interpretations of planet-like perturbations and of high-cadence observation not only for resolving the degeneracy but also for ensuring the unambiguous detection of the planet.

  7. Probing the Dark Matter Radial Profile in Lens Galaxies and the Size of X-Ray Emitting Region in Quasars with Microlensing

    Science.gov (United States)

    Jiménez-Vicente, J.; Mediavilla, E.; Kochanek, C. S.; Muñoz, J. A.

    2015-06-01

    We use X-ray and optical microlensing measurements to study the shape of the dark matter density profile in the lens galaxies and the size of the (soft) X-ray emission region. We show that single epoch X-ray microlensing is sensitive to the source size. Our results, in good agreement with previous estimates, show that the size of the X-ray emission region scales roughly linearly with the black hole mass, with a half-light radius of {{R}}1/2≃ (24+/- 14){{r}}{\\boldsymbol{g}} where {r}g={{GM}}{BH}/{c}2. This corresponds to a size of {log}({{R}}1/2/{cm})={15.6}-0.3+0.3 or ˜1 lt-day for a black hole mass of {M}{BH}={10}9 {M}⊙ . We simultaneously estimated the fraction of the local surface mass density in stars, finding that the stellar mass fraction is α = 0.20 ± 0.05 at an average radius of ˜ 1.9{R}e, where Re is the effective radius of the lens. This stellar mass fraction is insensitive to the X-ray source size and in excellent agreement with our earlier results based on optical data. By combining X-ray and optical microlensing data, we can divide this larger sample into two radial bins. We find that the surface mass density in the form of stars is α = 0.31 ± 0.15 and α = 0.13 ± 0.05 at (1.3+/- 0.3){R}e and (2.3+/- 0.3){R}e, respectively, in good agreement with expectations and some previous results.

  8. A simple method to determine time delays in the presence of microlensing: application to HE 0435-1112 and PG 1115+080

    Science.gov (United States)

    Tsvetkova, V. S.; Shulga, V. M.; Berdina, L. A.

    2016-10-01

    A method for determining the time delays in gravitationally lensed quasars is proposed. This method offers a simple and transparent procedure to mitigate the effects of microlensing. It is based on the fundamental properties of representation of quadratically integrable functions by their expansions in orthogonal polynomials series. The method was tested on the artificial light curves simulated for the Time Delay Challenge campaign (TDC0). The new estimates of the time delays in the gravitationally lensed quasars HE 0435-1223 and PG 1115+080 are obtained and compared with the results reported earlier by other authors.

  9. Probing the dark matter radial profile in lens galaxies and the size of X-ray emitting region in quasars with microlensing

    CERN Document Server

    Jiménez-Vicente, J; Kochanek, C S; Muñoz, J A

    2015-01-01

    We use X-ray and optical microlensing measurements of 47 image pairs in 18 lens systems to study the shape of the dark matter density profile in the lens galaxies and the size of the (soft) X-ray emission region. We show that single epoch X-ray microlensing is sensitive to the source size. Our results, in good agreement with previous estimates, show that the X-ray size scales roughly linearly with the black hole mass, with a half light radius of $R_{1/2}\\simeq(20\\pm12) r_g$ (for $r_g=GM_{BH}/c^2$). This corresponds to a size of $\\sim$ 1 light day for a black hole mass of $M_{BH}=10^9 M_\\sun$. We simultaneously estimated the fraction of the local surface mass density in stars, finding that the stellar mass fraction is $\\alpha=0.20\\pm0.05$ at an average radius of $\\sim 1.9 R_{e}$, where $R_e$ is the effective radius of the lens. This stellar mass fraction is insensitive to the X-ray source size and in excellent agreement with our earlier results based on optical data. By combining the X-ray and optical microlen...

  10. Events diary

    Science.gov (United States)

    2000-01-01

    as Imperial College, the Royal Albert Hall, the Royal College of Art, the Natural History and Science Museums and the Royal Geographical Society. Under the heading `Shaping the future together' BA2000 will explore science, engineering and technology in their wider cultural context. Further information about this event on 6 - 12 September may be obtained from Sandra Koura, BA2000 Festival Manager, British Association for the Advancement of Science, 23 Savile Row, London W1X 2NB (tel: 0171 973 3075, e-mail: sandra.koura@britassoc.org.uk ). Details of the creating SPARKS events may be obtained from creating.sparks@britassoc.org.uk or from the website www.britassoc.org.uk . Other events 3 - 7 July, Porto Alegre, Brazil VII Interamerican conference on physics education: The preparation of physicists and physics teachers in contemporary society. Info: IACPE7@if.ufrgs.br or cabbat1.cnea.gov.ar/iacpe/iacpei.htm 27 August - 1 September, Barcelona, Spain GIREP conference: Physics teacher education beyond 2000. Info: www.blues.uab.es/phyteb/index.html

  11. OGLE-2015-BLG-0479LA,B: Binary Gravitational Microlens Characterized by Simultaneous Ground-based and Space-based Observation

    CERN Document Server

    Han, C; Gould, A; Zhu, Wei; Street, R A; Yee, J C; Beichman, C; Bryden, C; Novati, S Calchi; Carey, S; Fausnaugh, M; Gaudi, B S; Henderson, Calen B; Shvartzvald, Y; Wibking, B; Szymański, M K; Soszyński, I; Skowron, J; Mróz, P; Poleski, R; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Wyrzykowski, Ł; Pawlak, M; Tsapras, Y; Hundertmark, M; Bachelet, E; Dominik, M; Bramich, D M; Cassan, A; Jaimes, R Figuera; Horne, K; Ranc, C; Schmidt, R; Snodgrass, C; Wambsganss, J; Steele, I A; Menzies, J; Mao, S; Bozza, V; Jørgensen, U G; Alsubai, K A; Ciceri, S; D'Ago, G; Haugbølle, T; Hessman, F V; Hinse, T C; Juncher, D; Korhonen, H; Mancini, L; Popovas, A; Rabus, M; Rahvar, S; Scarpetta, G; Skottfelt, J; Southworth, J; Starkey, D; Surdej, J; Wertz, O; Zarucki, M; Pogge, R W; DePoy, D L

    2016-01-01

    We present a combined analysis of the observations of the gravitational microlensing event OGLE-2015-BLG-0479 taken both from the ground and by the {\\it Spitzer Space Telescope}. The light curves seen from the ground and from space exhibit a time offset of $\\sim 13$ days between the caustic spikes, indicating that the relative lens-source positions seen from the two places are displaced by parallax effects. From modeling the light curves, we measure the space-based microlens parallax. Combined with the angular Einstein radius measured by analyzing the caustic crossings, we determine the mass and distance of the lens. We find that the lens is a binary composed of two G-type stars with masses $\\sim 1.0\\ M_\\odot$ and $\\sim 0.9\\ M_\\odot$ located at a distance $\\sim 3$ kpc. In addition, we are able to constrain the complete orbital parameters of the lens thanks to the precise measurement of the microlens parallax derived from the joint analysis. In contrast to the binary event OGLE-2014-BLG-1050, which was also ob...

  12. OGLE-2015-BLG-0196: Ground-based Gravitational Microlens Parallax Confirmed By Space-Based Observation

    CERN Document Server

    Han, C; Gould, A; Zhu, Wei; Szymański, M K; Soszyński, I; Skowron, J; Mróz, P; Poleski, R; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Pawlak, M; Yee, J C; Beichman, C; Novati, S Calchi; Carey, S; Bryden, C; Fausnaugh, M; Gaudi, B S; Henderson, Calen B; Shvartzvald, Y; Wibking, B

    2016-01-01

    In this paper, we present the analysis of the binary gravitational microlensing event OGLE-2015-BLG-0196. The event lasted for almost a year and the light curve exhibited significant deviations from the lensing model based on the rectilinear lens-source relative motion, enabling us to measure the microlens parallax. The ground-based microlens parallax is confirmed by the data obtained from space-based microlens observations using the {\\it Spitzer} telescope. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined up to the two-fold degeneracy: $u_00$ solutions caused by the well-known "ecliptic" degeneracy. It is found that the binary lens is composed of two M dwarf stars with similar masses $M_1=0.38\\pm 0.04\\ M_\\odot$ ($0.50\\pm 0.05\\ M_\\odot)$ and $M_2=0.38\\pm 0.04\\ M_\\odot$ ($0.55\\pm 0.06\\ M_\\odot$) and the distance to the lens is $D_{\\rm L}=2.77\\pm 0.23$ kpc ($3.30\\pm 0.29$ kpc). Here the physical parameter...

  13. Event Index - an LHCb Event Search System

    CERN Document Server

    Ustyuzhanin, Andrey

    2015-01-01

    During LHC Run 1, the LHCb experiment recorded around 1011 collision events. This paper describes Event Index | an event search system. Its primary function is to quickly select subsets of events from a combination of conditions, such as the estimated decay channel or number of hits in a subdetector. Event Index is essentially Apache Lucene [1] optimized for read-only indexes distributed over independent shards on independent nodes.

  14. Gastrointestinal events with clopidogrel

    DEFF Research Database (Denmark)

    Grove, Erik Lerkevang; Würtz, Morten; Schwarz, Peter

    2013-01-01

    Clopidogrel prevents cardiovascular events, but has been linked with adverse gastrointestinal (GI) complications, particularly bleeding events.......Clopidogrel prevents cardiovascular events, but has been linked with adverse gastrointestinal (GI) complications, particularly bleeding events....

  15. Direct Microlensing-Reverberation Observations of the Intrinsic magnetic Structure of AGN in Different Spectral States: A Tale of Two Quasars

    CERN Document Server

    Schild, Rudolph E; Robertson, Stanley L

    2007-01-01

    We show how direct microlensing-reverberation analysis performed on two well-known Quasars (Q2237 - The Einstein Cross and Q0957 - The Twin) can be used to observe the inner structure of two quasars which are in significantly different spectral states. These observations allow us to measure the detailed internal structure of quasar Q2237 in a radio quiet high-soft state, and compare it to quasar Q0957 in a radio loud low-hard state. We find that the observed differences in the spectral states of these two quasars can be understood as being due to the location of the inner radii of their accretion disks relative to the co-rotation radii of rotating intrinsically magnetic supermassive compact objects in the centers of these quasars.

  16. Synthesizing Exoplanet Demographics: A Single Population of Long-period Planetary Companions to M Dwarfs Consistent with Microlensing, Radial Velocity, and Direct Imaging Surveys

    Science.gov (United States)

    Clanton, Christian; Gaudi, B. Scott

    2016-03-01

    We present the first study to synthesize results from five different exoplanet surveys using three independent detection methods: microlensing, radial velocity, and direct imaging. The constraints derived herein represent the most comprehensive picture of the demographics of large-separation (≳2 AU) planets orbiting the most common stars in our Galaxy that has been constructed to date. We assume a simple, joint power-law planet distribution function of the form {d}2{N}{{pl}}/(d{log} {m}p d{log} a)={ A }{({m}p/{M}{{Sat}})}α {(a/2.5{{AU}})}β with an outer cutoff radius of the separation distribution function of aout. Generating populations of planets from these models and mapping them into the relevant observables for each survey, we use actual or estimated detection sensitivities to determine the expected observations for each survey. Comparing with the reported results, we derive constraints on the parameters \\{α ,β ,{ A },{a}{{out}}\\} that describe a single population of planets that is simultaneously consistent with the results of microlensing, radial velocity, and direct imaging surveys. We find median and 68% confindence intervals of α =-{0.86}-0.19+0.21 (-{0.85}-0.19+0.21), β ={1.1}-1.4+1.9 ({1.1}-1.3+1.9), { A }={0.21}-0.15+0.20 {{dex}}-2 ({0.21}-0.15+0.20 {{dex}}-2), and {a}{{out}}={10}-4.7+26 AU ({12}-6.2+50 AU) assuming “hot-start” (“cold-start”) planet evolutionary models. These values are consistent with all current knowledge of planets on orbits beyond ∼2 AU around single M dwarfs.

  17. Creating Special Events

    Science.gov (United States)

    deLisle, Lee

    2009-01-01

    "Creating Special Events" is organized as a systematic approach to festivals and events for students who seek a career in event management. This book looks at the evolution and history of festivals and events and proceeds to the nuts and bolts of event management. The book presents event management as the means of planning, organizing, directing,…

  18. Gravitational binary-lens events with prominent effects of lens orbital motion

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.; Han, C.; Choi, J.-Y. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, UMR 7095 CNRS-Université Pierre and Marie Curie, 98bis Bd Arago, F-75014 Paris (France); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Depoy, D. L. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Dong, Subo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Collaboration: OGLE Collaboration; μFUN Collaboration; PLANET Collaboration; RoboNet Collaboration; and others

    2013-12-01

    Gravitational microlensing events produced by lenses composed of binary masses are important because they provide a major channel for determining physical parameters of lenses. In this work, we analyze the light curves of two binary-lens events, OGLE-2006-BLG-277 and OGLE-2012-BLG-0031, for which the light curves exhibit strong deviations from standard models. From modeling considering various second-order effects, we find that the deviations are mostly explained by the effect of the lens orbital motion. We also find that lens parallax effects can mimic orbital effects to some extent. This implies that modeling light curves of binary-lens events not considering orbital effects can result in lens parallaxes that are substantially different from actual values and thus wrong determinations of physical lens parameters. This demonstrates the importance of routine consideration of orbital effects in interpreting light curves of binary-lens events. It is found that the lens of OGLE-2006-BLG-277 is a binary composed of a low-mass star and a brown dwarf companion.

  19. Detections of Planets in Binaries Through the Channel of Chang–Refsdal Gravitational Lensing Events

    Science.gov (United States)

    Han, Cheongho; Shin, In-Gu; Jung, Youn Kil

    2017-02-01

    Chang–Refsdal (C–R) lensing, which refers to the gravitational lensing of a point mass perturbed by a constant external shear, provides a good approximation in describing lensing behaviors of either a very wide or a very close binary lens. C–R lensing events, which are identified by short-term anomalies near the peak of high-magnification lensing light curves, are routinely detected from lensing surveys, but not much attention is paid to them. In this paper, we point out that C–R lensing events provide an important channel to detect planets in binaries, both in close and wide binary systems. Detecting planets through the C–R lensing event channel is possible because the planet-induced perturbation occurs in the same region of the C–R lensing-induced anomaly and thus the existence of the planet can be identified by the additional deviation in the central perturbation. By presenting the analysis of the actually observed C–R lensing event OGLE-2015-BLG-1319, we demonstrate that dense and high-precision coverage of a C–R lensing-induced perturbation can provide a strong constraint on the existence of a planet in a wide range of planet parameters. The sample of an increased number of microlensing planets in binary systems will provide important observational constraints in giving shape to the details of planet formation, which have been restricted to the case of single stars to date.

  20. Semi-parametric Robust Event Detection for Massive Time-Domain Databases

    CERN Document Server

    Blocker, Alexander W

    2013-01-01

    The detection and analysis of events within massive collections of time-series has become an extremely important task for time-domain astronomy. In particular, many scientific investigations (e.g. the analysis of microlensing and other transients) begin with the detection of isolated events in irregularly-sampled series with both non-linear trends and non-Gaussian noise. We outline a semi-parametric, robust, parallel method for identifying variability and isolated events at multiple scales in the presence of the above complications. This approach harnesses the power of Bayesian modeling while maintaining much of the speed and scalability of more ad-hoc machine learning approaches. We also contrast this work with event detection methods from other fields, highlighting the unique challenges posed by astronomical surveys. Finally, we present results from the application of this method to 87.2 million EROS-2 sources, where we have obtained a greater than 100-fold reduction in candidates for certain types of pheno...

  1. Keterlibatan Event Stakeholders pada Keberhasilan Event PR

    Directory of Open Access Journals (Sweden)

    Lidya Wati Evelina

    2013-03-01

    Full Text Available The objective of this article is to determine how event organizers collaborate with stakeholders including the media, particular community, sponsors, participants, venue providers, accommodation providers, carteres, legal and finance personnel, production, local trade, transportation providers, government and associations for implementation Public Relations event. This paper discusses about the things that must be done for the cooperation and the benefits of cooperation undertaken. The method used in this paper is qualitative research method based on observations, literature and case studies. The results of this research note that the event organizers or companies can together with the stakeholders (the other party make an event as mutually beneficial Public Relations. This means that all parties can achieve through the event. At the conclusion of an event Public Relations, all stakeholders involved for their own purposes. Event organizer must ensure that all stakeholders work together effectively in accordance with the agreed schedule and budget. One important feature of the agreement is to maintain a good flow of communication according to the needs of its stakeholders. All information is documented to avoid misunderstandings. Collaboration between stakeholders continuously until the event is completed. Discussion of issues that arise during the event takes place between the committee with various stakeholders is an important thing for the evaluation and response to the events that occurred.

  2. Synthesizing Exoplanet Demographics: A Single Population of Long-Period Planetary Companions to M Dwarfs Consistent with Microlensing, Radial Velocity, and Direct Imaging Surveys

    CERN Document Server

    Clanton, Christian

    2015-01-01

    We present the first study to synthesize results from five different exoplanet surveys using three independent detection methods: microlensing, radial velocity, and direct imaging. The constraints derived herein represent the most comprehensive picture of the demographics of large-separation (>~ 2 AU) planets orbiting the most common stars in our Galaxy that has been constructed to date. We assume a simple, joint power-law planet distribution function of the form d^2N_{pl}/[dlog(m_p)dlog(a)] = A(m_p/M_{Sat})^{alpha}(a/2.5 AU)^{beta} with an outer cutoff radius of the separation distribution function of a_{out}. Generating populations of planets from these models and mapping them into the relevant observables for each survey, we use actual or estimated detection sensitivities to determine the expected observations for each survey. Comparing with the reported results, we derive constraints on the parameters {alpha, beta, A, a_{out}} that describe a single population of planets that is simultaneously consistent ...

  3. Episodes, events, and models

    Directory of Open Access Journals (Sweden)

    Sangeet eKhemlani

    2015-10-01

    Full Text Available We describe a novel computational theory of how individuals segment perceptual information into representations of events. The theory is inspired by recent findings in the cognitive science and cognitive neuroscience of event segmentation. In line with recent theories, it holds that online event segmentation is automatic, and that event segmentation yields mental simulations of events. But it posits two novel principles as well: first, discrete episodic markers track perceptual and conceptual changes, and can be retrieved to construct event models. Second, the process of retrieving and reconstructing those episodic markers is constrained and prioritized. We describe a computational implementation of the theory, as well as a robotic extension of the theory that demonstrates the processes of online event segmentation and event model construction. The theory is the first unified computational account of event segmentation and temporal inference. We conclude by demonstrating now neuroimaging data can constrain and inspire the construction of process-level theories of human reasoning.

  4. The global event system

    Energy Technology Data Exchange (ETDEWEB)

    Winans, J.

    1994-03-02

    The support for the global event system has been designed to allow an application developer to control the APS event generator and receiver boards. This is done by the use of four new record types. These records are customized and are only supported by the device support modules for the APS event generator and receiver boards. The use of the global event system and its associated records should not be confused with the vanilla EPICS events and the associated event records. They are very different.

  5. Event dependent sampling of recurrent events

    DEFF Research Database (Denmark)

    Kvist, Tine Kajsa; Andersen, Per Kragh; Angst, Jules

    2010-01-01

    The effect of event-dependent sampling of processes consisting of recurrent events is investigated when analyzing whether the risk of recurrence increases with event count. We study the situation where processes are selected for study if an event occurs in a certain selection interval. Motivation...... retrospective and prospective disease course histories are used. We examine two methods to correct for the selection depending on which data are used in the analysis. In the first case, the conditional distribution of the process given the pre-selection history is determined. In the second case, an inverse......-probability-of-selection weighting scheme is suggested. The ability of the methods to correct for the bias due to selection is investigated with simulations. Furthermore, the methods are applied to affective disease data from a register-based study (Kessing et al. Br J Psychiatry 185:372-377, 2004a) and from a long-term clinical...

  6. Traumatic events and children

    Science.gov (United States)

    ... stabbing of a person Sudden death of a parent or trusted caregiver Hospitalization Examples of traumatic events that your child experiences over and over are: Physical or emotional abuse Sexual abuse Gang violence War Terrorist events

  7. Advertising Effectiveness In Events

    OpenAIRE

    Jain, Sushilkumar

    2012-01-01

    Confronted with decreasing effectiveness of the classic marketing communications, events have become an increasingly popular alternative for marketers. Events constitute one of the most exciting and fastest growing forms of leisure and business. With time, the decreasing effectiveness of classical marketing communications boosted the use of events for marketing and making brand awareness. Event marketing is seen as the unique opportunity to integrate the firm’s communication activities like p...

  8. Event generators at BESⅢ

    Institute of Scientific and Technical Information of China (English)

    PING Rong-Gang

    2008-01-01

    We present a brief remark and introduction to event generators for tau-charm physics currently used at BESⅢ,including KKMC,BesEvtGen,Bhlumi,Bhwide,Babayaga and inclusive Monte-Carlo event generators.This paper provides basic information on event generators for BESⅢ users.

  9. Fully solution-processed organic light-emitting electrochemical cells (OLEC) with inkjet-printed micro-lenses for disposable lab-on-chip applications at ambient conditions

    Science.gov (United States)

    Shu, Zhe; Pabst, Oliver; Beckert, Erik; Eberhardt, Ramona; Tünnermann, Andreas

    2016-02-01

    Microfluidic lab-on-chip devices can be used for chemical and biological analyses such as DNA tests or environmental monitoring. Such devices integrate most of the basic functionalities needed for scientific analysis on a microfluidic chip. When using such devices, cost and space-intensive lab equipment is no longer necessary. However, in order to make a monolithic and cost-efficient/disposable microfluidic sensing device, direct integration of the excitation light source for fluorescent sensing is often required. To achieve this, we introduce a fully solution processable deviation of OLEDs, organic light-emitting electrochemical cells (OLECs), as a low-cost excitation light source for a disposable microfluidic sensing platform. By mixing metal ions and a solid electrolyte with light-emitting polymers as active materials, an in-situ doping and in-situ PN-junction can be generated within a three layer sandwich device. Thanks to this doping effect, work function adaptation is not necessary and air-stable electrode can be used. An ambient manufacturing process for fully solution-processed OLECs is presented, which consist of a spin-coated blue light-emitting polymer plus dopants on an ITO cathode and an inkjet-printed PEDOT:PSS transparent top anode. A fully transparent blue OLEC is able to obtain light intensity > 2500 cd/m2 under pulsed driving mode and maintain stable after 1000 cycles, which fulfils requirements for simple fluorescent on-chip sensing applications. However, because of the large refractive index difference between substrates and air, about 80% of emitted light is trapped inside the device. Therefore, inkjet printed micro-lenses on the rear side are introduced here to further increase light-emitting brightness.

  10. The PHENIX Event Builder

    Science.gov (United States)

    Winter, David

    2004-10-01

    The PHENIX Event Builder is a critical part of the back-end of the PHENIX DAQ. It is reponsible for assembling event fragments from each subsystem into complete events ready for archiving. It allows subsystems to be read out either in parallel or simultaneously while supporting a high rate of archiving. Additionally, it implements an environment where Level-2 trigger algorithms may be optionally executed, providing the ability to tag and/or filter rare physics events. Up to and including RHIC Run-4, the Event Builder was implemented as a set of three Windows NT/2000 multithreaded executables that run on a farm of over 100 dual-cpu 1U servers connected via a Foundry Layer2/3 Gigabit switch. Under this architecture it has been capable of recording a wide range of event sizes from central Au-Au to p-p interactions, with data archiving rates of over 400 MB/s at 2 KHz event rates. Between Runs 4 and 5, the Event Builder will be ported to Linux. Preliminary work has shown we can expect great improvements in performance when moving to this platform for Run 5. The PHENIX Event Builder design and implementation, as well as performance and plans for future development, will be discussed.

  11. The Terrorist Event

    OpenAIRE

    Nichols, Bill

    2007-01-01

    In his article "The Terrorist Event," Bill Nichols examines how the US media attempted to make meaning of the events of 9/11. How were news anchors and producers to explain an event that escaped their comprehension? Without context or historical equivalence in the US, news outlets groped for a narrative in which to frame the event even if that meant creating the meaning themselves. In their attempt to create meaning, what sorts of fetishes and fantasies did they draw-on and in turn create? Th...

  12. Features, Events, and Processes: Disruptive Events

    Energy Technology Data Exchange (ETDEWEB)

    J. King

    2004-03-31

    The primary purpose of this analysis is to evaluate seismic- and igneous-related features, events, and processes (FEPs). These FEPs represent areas of natural system processes that have the potential to produce disruptive events (DE) that could impact repository performance and are related to the geologic processes of tectonism, structural deformation, seismicity, and igneous activity. Collectively, they are referred to as the DE FEPs. This evaluation determines which of the DE FEPs are excluded from modeling used to support the total system performance assessment for license application (TSPA-LA). The evaluation is based on the data and results presented in supporting analysis reports, model reports, technical information, or corroborative documents that are cited in the individual FEP discussions in Section 6.2 of this analysis report.

  13. Features, Events, and Processes: Disruptive Events

    Energy Technology Data Exchange (ETDEWEB)

    P. Sanchez

    2004-11-08

    The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the disruptive events features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for license application (TSPA-LA). A screening decision, either ''Included'' or ''Excluded,'' is given for each FEP, along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), and (f) [DIRS 156605]. The FEPs addressed in this report deal with both seismic and igneous disruptive events, such as fault displacements through the repository and an igneous intrusion into the repository. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded). Previous versions of this report were developed to support the total system performance assessments (TSPA) for various prior repository designs. This revision addresses the repository design for the license application (LA).

  14. The Agency of Event

    DEFF Research Database (Denmark)

    Nicholas, Paul; Tamke, Martin; Riiber, Jacob

    2014-01-01

    This paper explores the notion of agency within event-based models. We present an event-based modeling approach that links interdependent generative, analytic and decision making sub-models within a system of exchange. Two case study projects demonstrate the underlying modeling concepts and metho...

  15. CHED Events: Philadelphia

    Science.gov (United States)

    Wink, Donald J.

    2008-08-01

    These Division of Chemical Education (CHED) Committee meetings and events are planned for the Fall 2008 ACS Meeting in Philadelphia. Most will take place in the Sheraton Philadelphia City Center Hotel, 17th and Race Streets: This includes the Sunday evening Reception and Social Event; there will be no CHED Banquet.

  16. Activating Event Knowledge

    Science.gov (United States)

    Hare, Mary; Jones, Michael; Thomson, Caroline; Kelly, Sarah; McRae, Ken

    2009-01-01

    An increasing number of results in sentence and discourse processing demonstrate that comprehension relies on rich pragmatic knowledge about real-world events, and that incoming words incrementally activate such knowledge. If so, then even outside of any larger context, nouns should activate knowledge of the generalized events that they denote or…

  17. Committed Sport Event Volunteers

    Science.gov (United States)

    Han, Keunsu; Quarterman, Jerome; Strigas, Ethan; Ha, Jaehyun; Lee, Seungbum

    2013-01-01

    The purpose of this study was to investigate the relationships among selected demographic characteristics (income, education and age), motivation and commitment of volunteers at a sporting event. Three-hundred and five questionnaires were collected from volunteers in a marathon event and analyzed using structural equation modeling (SEM). Based on…

  18. The ATLAS Event Builder

    CERN Document Server

    Vandelli, W; Battaglia, A; Beck, H P; Blair, R; Bogaerts, A; Bosman, M; Ciobotaru, M; Cranfield, R; Crone, G; Dawson, J; Dobinson, Robert W; Dobson, M; Dos Anjos, A; Drake, G; Ermoline, Y; Ferrari, R; Ferrer, M L; Francis, D; Gadomski, S; Gameiro, S; Gorini, B; Green, B; Haberichter, W; Haberli, C; Hauser, R; Hinkelbein, C; Hughes-Jones, R; Joos, M; Kieft, G; Klous, S; Korcyl, K; Kordas, K; Kugel, A; Leahu, L; Lehmann, G; Martin, B; Mapelli, L; Meessen, C; Meirosu, C; Misiejuk, A; Mornacchi, G; Müller, M; Nagasaka, Y; Negri, A; Pasqualucci, E; Pauly, T; Petersen, J; Pope, B; Schlereth, J L; Spiwoks, R; Stancu, S; Strong, J; Sushkov, S; Szymocha, T; Tremblet, L; Ünel, G; Vermeulen, J; Werner, P; Wheeler-Ellis, S; Wickens, F; Wiedenmann, W; Yu, M; Yasu, Y; Zhang, J; Zobernig, H; 2007 IEEE Nuclear Science Symposium and Medical Imaging Conference

    2008-01-01

    Event data from proton-proton collisions at the LHC will be selected by the ATLAS experiment in a three-level trigger system, which, at its first two trigger levels (LVL1+LVL2), reduces the initial bunch crossing rate of 40~MHz to $sim$3~kHz. At this rate, the Event Builder collects the data from the readout system PCs (ROSs) and provides fully assembled events to the Event Filter (EF). The EF is the third trigger level and its aim is to achieve a further rate reduction to $sim$200~Hz on the permanent storage. The Event Builder is based on a farm of O(100) PCs, interconnected via a Gigabit Ethernet to O(150) ROSs. These PCs run Linux and multi-threaded software applications implemented in C++. All the ROSs, and substantial fractions of the Event Builder and Event Filter PCs have been installed and commissioned. We report on performance tests on this initial system, which is capable of going beyond the required data rates and bandwidths for Event Building for the ATLAS experiment.

  19. Measurement of the abundance of stellar mass compact objects in the galactic halo by detecting micro-lenses in the Large Magellanic Cloud; Mesure de l'abondance des astres sombres de masse stellaire dans le halo galactique par la recherche de phenomenes de microlentilles vers les nuages de magellan

    Energy Technology Data Exchange (ETDEWEB)

    Lasserre, Th

    2000-05-09

    Many experimental and theoretical results lead to the conclusion that at least 80 percent of the mass of our Galaxy is dark. Part of this so-called dark matter could be in the form of stellar mass compact objects, called MACHOS; these could be detected using the gravitational microlensing effect. The first generation experiments EROS1 and MACHO have strongly constrained the galactic abundance of objects lighter than 0.01 solar mass to less than 10 percent of the total mass. In parallel, the observation by the MACHO group of massive candidates (half the Sun's mass), numerous enough to constitute 50 percent of galactic dark matter, was a further motivation for the EROS group to extend this search to stellar mass objects in a second phase, EROS2. The present work deals with the analysis of 25 million stellar light curves in the Large Magellanic Cloud, observed for three years in order to extract the rare microlensing candidates and to measure the galactic halo mass fraction in the form of compact objects. After recalling the motivations of this search and the theoretical context, I describe the EROS2 experiment. The observational strategy and the photometric reduction procedures needed to deal with the 1.2 To of data are then presented. A new method to detect micro-lenses is detailed, as well as a discussion of background light curves, poorly known. We do not find enough microlensing candidates to explain the galactic rotation curve; this confirms, and improve on previous EROS1 and EROS2 results. Combining all results from EROS allows to exclude that MACHOS with a mass between 10 e-7 and 10 solar mass are important constituents of the galactic halo. This statement agrees with recent results from the MACHO group, although our interpretations differ, namely on the topics of the location of the lenses, and of a possible contamination of the microlensing ample by background phenomena. (author)

  20. CCG - News & Events

    Science.gov (United States)

    NCI's Center for Cancer Genomics (CCG) has been widely recognized for its research efforts to facilitiate advances in cancer genomic research and improve patient outcomes. Find the latest news about and events featuring CCG.

  1. RAS Initiative - Events

    Science.gov (United States)

    The NCI RAS Initiative has organized multiple events with outside experts to discuss how the latest scientific and technological breakthroughs can be applied to discover vulnerabilities in RAS-driven cancers.

  2. Electrifying Current Events.

    Science.gov (United States)

    Smith, Philip

    1980-01-01

    The author describes how he has adapted the television quiz show format of "College Bowl" to current events study for junior high school students. An insert explains use of the same technique with fourth graders. (SJL)

  3. "Universe" event at AIMS

    Science.gov (United States)

    2008-06-01

    Report of event of 11 May 2008 held at the African Institute of Mathematical Sciences (Muizenberg, Cape), with speakers Michael Griffin (Administrator of NASA), Stephen Hawking (Cambridge), David Gross (Kavli Institute, Santa Barbara) and George Smoot (Berkeley).

  4. Event visualization in ATLAS

    CERN Document Server

    Bianchi, Riccardo-Maria; The ATLAS collaboration

    2017-01-01

    At the beginning, HEP experiments made use of photographical images both to record and store experimental data and to illustrate their findings. Then the experiments evolved and needed to find ways to visualize their data. With the availability of computer graphics, software packages to display event data and the detector geometry started to be developed. Here, an overview of the usage of event display tools in HEP is presented. Then the case of the ATLAS experiment is considered in more detail and two widely used event display packages are presented, Atlantis and VP1, focusing on the software technologies they employ, as well as their strengths, differences and their usage in the experiment: from physics analysis to detector development, and from online monitoring to outreach and communication. Towards the end, the other ATLAS visualization tools will be briefly presented as well. Future development plans and improvements in the ATLAS event display packages will also be discussed.

  5. Paroxysmal Nonepileptic Events

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-11-01

    Full Text Available Paroxysmal events that mimic epilepsy, and their precipitants, prodromes, and distinguishing features are reviewed by researchers at Texas Tech University, Lubbock, TX, and American University of Beirut, New York.

  6. CHED Events: New Orleans

    Science.gov (United States)

    Wink, Donald J.

    2008-03-01

    These Division of Chemical Education (CHED) Committee meetings and events are planned for the Spring 2008 ACS Meeting in New Orleans. Most will take place in the Hilton Riverside Hotel, 2 Poydras Street; this includes the Sunday evening Reception and Social Event; there will be no CHED Banquet. Exceptions are the Sunday evening Poster Session and the Undergraduate Poster Sessions, which will be in Hall A of the Morial Convention Center.

  7. Gargamelle: neutral current event

    CERN Multimedia

    1973-01-01

    This event shows real tracks of particles from the 1200 litre Gargamelle bubble chamber that ran on the PS from 1970 to 1976 and on the SPS from 1976 to 1979. In this image a neutrino passes close to a nucleon and reemerges as a neutrino. Such events are called neutral curent, as they are mediated by the Z0 boson which has no electric charge.

  8. Concepts of event-by-event analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stroebele, H. [Universitaet Frankfurt (Germany)

    1995-07-15

    The particles observed in the final state of nuclear collisions can be divided into two classes: those which are susceptible to strong interactions and those which are not, like leptons and the photon. The bulk properties of the {open_quotes}matter{close_quotes} in the reaction zone may be read-off the kinematical characteristics of the particles observable in the final state. These characteristics are strongly dependent on the last interaction these particles have undergone. In a densly populated reaction zone strongly interacting particles will experience many collisions after they have been formed and before they emerge into the asymptotic final state. For the particles which are not sensitive to strong interactions their formation is also their last interaction. Thus photons and leptons probe the period during which they are produced whereas hadrons reflect the so called freeze-out processes, which occur during the late stage in the evolution of the reaction when the population density becomes small and the mean free paths long. The disadvantage of the leptons and photons is their small production cross section; they cannot be used in an analysis of the characteristics of individual collision events, because the number of particles produced per event is too small. The hadrons, on the other hand, stem from the freeze-out period. Information from earlier periods requires multiparticle observables in the most general sense. It is one of the challenges of present day high energy nuclear physics to establish and understand global observables which differentiate between mere hadronic scenarios, i.e superposition of hadronic interactions, and the formation of a partonic (short duration) steady state which can be considered a new state of matter, the Quark-Gluon Plasma.

  9. Discrete-Event Simulation

    Directory of Open Access Journals (Sweden)

    Prateek Sharma

    2015-04-01

    Full Text Available Abstract Simulation can be regarded as the emulation of the behavior of a real-world system over an interval of time. The process of simulation relies upon the generation of the history of a system and then analyzing that history to predict the outcome and improve the working of real systems. Simulations can be of various kinds but the topic of interest here is one of the most important kind of simulation which is Discrete-Event Simulation which models the system as a discrete sequence of events in time. So this paper aims at introducing about Discrete-Event Simulation and analyzing how it is beneficial to the real world systems.

  10. Detection of anomalous events

    Energy Technology Data Exchange (ETDEWEB)

    Ferragut, Erik M.; Laska, Jason A.; Bridges, Robert A.

    2016-06-07

    A system is described for receiving a stream of events and scoring the events based on anomalousness and maliciousness (or other classification). The system can include a plurality of anomaly detectors that together implement an algorithm to identify low-probability events and detect atypical traffic patterns. The anomaly detector provides for comparability of disparate sources of data (e.g., network flow data and firewall logs.) Additionally, the anomaly detector allows for regulatability, meaning that the algorithm can be user configurable to adjust a number of false alerts. The anomaly detector can be used for a variety of probability density functions, including normal Gaussian distributions, irregular distributions, as well as functions associated with continuous or discrete variables.

  11. Forecasting Turbine Icing Events

    DEFF Research Database (Denmark)

    Davis, Neil; Hahmann, Andrea N.; Clausen, Niels-Erik

    In this study, we present a method for forecasting icing events. The method is validated at two European wind farms in with known icing events. The icing model used was developed using current ice accretion methods, and newly developed ablation algorithms. The model is driven by inputs from the WRF...... mesoscale model, allowing for both climatological estimates of icing and short term icing forecasts. The current model was able to detect periods of icing reasonably well at the warmer site. However at the cold climate site, the model was not able to remove ice quickly enough leading to large ice...... accumulations, which have not been seen in observations. In addition to the model evaluation we were able to investigate the potential occurrence of ice induced power loss at two wind parks in Europe using observed data. We found that the potential loss during an icing event is large even when the turbine...

  12. Forecasting Turbine Icing Events

    DEFF Research Database (Denmark)

    Davis, Neil; Hahmann, Andrea N.; Clausen, Niels-Erik;

    2012-01-01

    is not shut down for its protection. We also found that there is a a large spread across the various turbines within a wind park, in the amount of icing. This is currently not taken into account by our model. Evaluating and adding these small scale differences to the model will be undertaken as future work....... accumulations, which have not been seen in observations. In addition to the model evaluation we were able to investigate the potential occurrence of ice induced power loss at two wind parks in Europe using observed data. We found that the potential loss during an icing event is large even when the turbine......In this study, we present a method for forecasting icing events. The method is validated at two European wind farms in with known icing events. The icing model used was developed using current ice accretion methods, and newly developed ablation algorithms. The model is driven by inputs from the WRF...

  13. Events and Effects

    DEFF Research Database (Denmark)

    Rytter, Mikkel

    2010-01-01

    Analyzing the period of ‘intensive transnationalism’ among Pakistani migrants in Denmark precipitated by the 2005 earthquake in Kashmir, this article explores the relationship between events and effects on a global scale. One significant initiative after the disaster was the founding of an ad hoc......, and national identity politics in Denmark. Despite the medical doctors’ efforts and intentions, the out- come was framed by 9/11, which has become the major critical event of the decade—one that has supported a developing cleavage between the Danish majority and Denmark’s Muslim immigrant minority....

  14. Event Classification using Concepts

    NARCIS (Netherlands)

    Boer, M.H.T. de; Schutte, K.; Kraaij, W.

    2013-01-01

    The semantic gap is one of the challenges in the GOOSE project. In this paper a Semantic Event Classification (SEC) system is proposed as an initial step in tackling the semantic gap challenge in the GOOSE project. This system uses semantic text analysis, multiple feature detectors using the BoW mod

  15. On Objects and Events

    DEFF Research Database (Denmark)

    Eugster, Patrick Thomas; Guerraoui, Rachid; Damm, Christian Heide

    2001-01-01

    This paper presents linguistic primitives for publish/subscribe programming using events and objects. We integrate our primitives into a strongly typed object-oriented language through four mechanisms: (1) serialization, (2) multiple sub typing, (3) closures, and (4) deferred code evaluation. We...

  16. Brief resolved unexplained event

    Science.gov (United States)

    Arane, Karen; Claudius, Ilene; Goldman, Ran D.

    2017-01-01

    Abstract Question For many years, the term apparent life-threatening event (ALTE) was associated with sudden infant death syndrome, and parents who described an acute event in their infants were sent to the hospital for admission. I understand that for infants new terminology is recommended. What is the current approach to a near-death experience of an infant? Answer A recent clinical practice guideline revised the name and definition of an ALTE to a brief resolved unexplained event (BRUE). The diagnosis of BRUE in infants younger than 1 year of age is made when infants experience 1 of the following BRUE symptoms: a brief episode (ie, less than 1 minute and usually less than 20 to 30 seconds) that is entirely resolved (infant is at baseline), which remains unexplained after the history and physical examination are completed, and includes an event characterized by cyanosis or pallor; absent, decreased, or irregular breathing; hypertonia or hypotonia; or altered responsiveness. Low-risk infants should not be admitted to the hospital and overtesting is discouraged. PMID:28115439

  17. Language As Social Event.

    Science.gov (United States)

    Harste, Jerome C.

    A taxonomy developed for the study of the growth and development of written language from the perspective of social event was tested with a group of 68 children, aged three to six years. The subjects were presented with a wide variety of environmental print messages (road signs, toys, fast food signs, and household products) and were questioned…

  18. Television Ceremonial Events.

    Science.gov (United States)

    Dayan, Daniel; Katz, Elihu

    1985-01-01

    Analyzes the impact of televised ceremonies (such as the marriage of Prince Charles and Lady Diana) as "media events" which allow viewers to vicariously enter into the ceremony. Compares them with cult movies that, over repeated viewing, encourage audience "participation." Focuses on the narrator's/commentator's role in shaping…

  19. The CMS Event Builder

    CERN Document Server

    Brigljevic, V; Cano, E; Cittolin, Sergio; Csilling, Akos; Gigi, D; Glege, F; Gómez-Reino, Robert; Gulmini, M; Gutleber, J; Jacobs, C; Kozlovszky, Miklos; Larsen, H; Magrans de Abril, Ildefons; Meijers, F; Meschi, E; Murray, S; Oh, A; Orsini, L; Pollet, L; Rácz, A; Samyn, D; Scharff-Hansen, P; Schwick, C; Sphicas, Paris; ODell, V; Suzuki, I; Berti, L; Maron, G; Toniolo, N; Zangrando, L; Ninane, A; Erhan, S; Bhattacharya, S; Branson, J G

    2003-01-01

    The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragmen...

  20. Focusing properties of mushroom microlenses

    CERN Document Server

    Boriskin, A V; Benson, T; Sewell, P; Nosich, A I

    2010-01-01

    Focusing properties of a novel type photoresist microlens are studied. A specific character of the microlens is its mushroom shape. Recently it was predicted and experimentally revealed that such a lens integrated with a light-emitting diode is capable of enhancing its output efficiency and directivity. In our paper we describe the true electromagnetic performance of a mushroom lens by applying a mathematically rigorous method of boundary integral equations. Numerical results are presented for the mushroom lens illuminated with a plane E-polarized wave and include figures describing the evolution of the lens focal spot and near field maps.

  1. Traumatic-event headaches

    Directory of Open Access Journals (Sweden)

    Haas David C

    2004-10-01

    Full Text Available Abstract Background Chronic headaches from head trauma and whiplash injury are well-known and common, but chronic headaches from other sorts of physical traumas are not recognized. Methods Specific information was obtained from the medical records of 15 consecutive patients with chronic headaches related to physically injurious traumatic events that did not include either head trauma or whiplash injury. The events and the physical injuries produced by them were noted. The headaches' development, characteristics, duration, frequency, and accompaniments were recorded, as were the patients' use of pain-alleviative drugs. From this latter information, the headaches were classified by the diagnostic criteria of the International Headache Society as though they were naturally-occurring headaches. The presence of other post-traumatic symptoms and litigation were also recorded. Results The intervals between the events and the onset of the headaches resembled those between head traumas or whiplash injuries and their subsequent headaches. The headaches themselves were, as a group, similar to those after head trauma and whiplash injury. Thirteen of the patients had chronic tension-type headache, two had migraine. The sustained bodily injuries were trivial or unidentifiable in nine patients. Fabrication of symptoms for financial remuneration was not evident in these patients of whom seven were not even seeking payments of any kind. Conclusions This study suggests that these hitherto unrecognized post-traumatic headaches constitute a class of headaches characterized by a relation to traumatic events affecting the body but not including head or whiplash traumas. The bodily injuries per se can be discounted as the cause of the headaches. So can fabrication of symptoms for financial remuneration. Altered mental states, not systematically evaluated here, were a possible cause of the headaches. The overall resemblance of these headaches to the headaches after

  2. Solar extreme events

    CERN Document Server

    Hudson, Hugh S

    2015-01-01

    Solar flares and CMEs have a broad range of magnitudes. This review discusses the possibility of "extreme events," defined as those with magnitudes greater than have been seen in the existing historical record. For most quantitative measures, this direct information does not extend more than a century and a half into the recent past. The magnitude distributions (occurrence frequencies) of solar events (flares/CMEs) typically decrease with the parameter measured or inferred (peak flux, mass, energy etc. Flare radiation fluxes tend to follow a power law slightly flatter than $S^{-2}$, where S represents a peak flux; solar particle events (SPEs) follow a still flatter power law up to a limiting magnitude, and then appear to roll over to a steeper distribution, which may take an exponential form or follow a broken power law. This inference comes from the terrestrial $^{14}$C record and from the depth dependence of various radioisotope proxies in the lunar regolith and in meteorites. Recently major new observation...

  3. PREVENTABLE ERRORS: NEVER EVENTS

    Directory of Open Access Journals (Sweden)

    Narra Gopal

    2014-07-01

    Full Text Available Operation or any invasive procedure is a stressful event involving risks and complications. We should be able to offer a guarantee that the right procedure will be done on right person in the right place on their body. “Never events” are definable. These are the avoidable and preventable events. The people affected from consequences of surgical mistakes ranged from temporary injury in 60%, permanent injury in 33% and death in 7%”.World Health Organization (WHO [1] has earlier said that over seven million people across the globe suffer from preventable surgical injuries every year, a million of them even dying during or immediately after the surgery? The UN body quantified the number of surgeries taking place every year globally 234 million. It said surgeries had become common, with one in every 25 people undergoing it at any given time. 50% never events are preventable. Evidence suggests up to one in ten hospital admissions results in an adverse incident. This incident rate is not acceptable in other industries. In order to move towards a more acceptable level of safety, we need to understand how and why things go wrong and have to build a reliable system of working. With this system even though complete prevention may not be possible but we can reduce the error percentage2. To change present concept towards patient, first we have to change and replace the word patient with medical customer. Then our outlook also changes, we will be more careful towards our customers.

  4. LHCb Event display

    CERN Document Server

    Trisovic, Ana

    2014-01-01

    The LHCb Event Display was made for educational purposes at the European Organization for Nuclear Research, CERN in Geneva, Switzerland. The project was implemented as a stand-alone application using C++ and ROOT, a framework developed by CERN for data analysis. This paper outlines the development and architecture of the application in detail, as well as the motivation for the development and the goals of the exercise. The application focuses on the visualization of events recorded by the LHCb detector, where an event represents a set of charged particle tracks in one proton-proton collision. Every particle track is coloured by its type and can be selected to see its essential information such as mass and momentum. The application allows students to save this information and calculate the invariant mass for any pair of particles. Furthermore, the students can use additional calculating tools in the application and build up a histogram of these invariant masses. The goal for the students is to find a $D^0$ par...

  5. ON THE DETECTABILITY OF A PREDICTED MESOLENSING EVENT ASSOCIATED WITH THE HIGH PROPER MOTION STAR VB 10

    Energy Technology Data Exchange (ETDEWEB)

    Lepine, Sebastien [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); DiStefano, Rosanne, E-mail: lepine@amnh.org, E-mail: rd@cfa.harvard.edu [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2012-04-10

    Extrapolation of the astrometric motion of the nearby low-mass star VB 10 indicates that sometime in late 2011 December or during the first 2-3 months of 2012, the star will make a close approach to a background point source. Based on astrometric uncertainties, we estimate a 1 in 2 chance that the distance of closest approach {rho}{sub min} will be less than 100 mas, a 1 in 5 chance that {rho}{sub min} < 50 mas, and a 1 in 10 chance that {rho}{sub min} < 20 mas. The last would result in a microlensing event with a 6% magnification in the light from the background source and an astrometric shift of 3.3 mas. The lensing signal will however be significantly diluted by the light from VB 10, which is 1.5 mag brighter than the background source in B band, 5 mag brighter in I band, and 10 mag brighter in K band, making the event undetectable in all but the bluer optical bands. However, we show that if VB 10 happens to harbor a {approx}1 M{sub J} planet on a moderately wide ( Almost-Equal-To 0.18 AU-0.84 AU) orbit, there is a chance (1% to more than 10%, depending on the distance of closest approach and orbital period and inclination) that a passage of the planet closer to the background source will result in a secondary event of higher magnification. The detection of secondary events could be made possible with a several-times-per-night multi-site monitoring campaign.

  6. On the Detectability of a Predicted Mesolensing Event Associated with the High Proper Motion Star VB 10

    Science.gov (United States)

    Lépine, Sébastien; DiStefano, Rosanne

    2012-04-01

    Extrapolation of the astrometric motion of the nearby low-mass star VB 10 indicates that sometime in late 2011 December or during the first 2-3 months of 2012, the star will make a close approach to a background point source. Based on astrometric uncertainties, we estimate a 1 in 2 chance that the distance of closest approach ρmin will be less than 100 mas, a 1 in 5 chance that ρmin < 50 mas, and a 1 in 10 chance that ρmin < 20 mas. The last would result in a microlensing event with a 6% magnification in the light from the background source and an astrometric shift of 3.3 mas. The lensing signal will however be significantly diluted by the light from VB 10, which is 1.5 mag brighter than the background source in B band, 5 mag brighter in I band, and 10 mag brighter in K band, making the event undetectable in all but the bluer optical bands. However, we show that if VB 10 happens to harbor a ~1 MJ planet on a moderately wide (≈0.18 AU-0.84 AU) orbit, there is a chance (1% to more than 10%, depending on the distance of closest approach and orbital period and inclination) that a passage of the planet closer to the background source will result in a secondary event of higher magnification. The detection of secondary events could be made possible with a several-times-per-night multi-site monitoring campaign. Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA), and the Canadian Astronomy Data Centre (CADC/NRC/CSA).

  7. Event-Based Conceptual Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2009-01-01

    The purpose of the paper is to obtain insight into and provide practical advice for event-based conceptual modeling. We analyze a set of event concepts and use the results to formulate a conceptual event model that is used to identify guidelines for creation of dynamic process models and static...... information models. We characterize events as short-duration processes that have participants, consequences, and properties, and that may be modeled in terms of information structures. The conceptual event model is used to characterize a variety of event concepts and it is used to illustrate how events can...... be used to integrate dynamic modeling of processes and static modeling of information structures. The results are unique in the sense that no other general event concept has been used to unify a similar broad variety of seemingly incompatible event concepts. The general event concept can be used...

  8. Sample Spaces and Events(2)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Definition: An event is a subset E of the sample space S. The impossible event is the subset E = φ (empty set). The certain event is the subset E = S (sample space).Note that any subset of S represents an event, according to this defintion. Thus, in rolling a die the subset E={1,2,5} represents an event, which we can describe in words as "the die comes up 1,2, or 5. "

  9. EventSlider User Manual

    Science.gov (United States)

    2016-09-01

    FrameworkElement parent class), which allows for efficient batch setting of these main properties without changing the display until the initialization is...a single click, or a tap, near or on an event line. 4. Library and Namespace The EventSlider control has been compiled into the following dynamic...namespace:WPFControls.EventSlider;assembly=WPFControls.EventSlider" Only a single class is exposed in this namespace, the EventSlider class. All methods, properties, and

  10. Detection of solar events

    Science.gov (United States)

    Fischbach, Ephraim; Jenkins, Jere

    2013-08-27

    A flux detection apparatus can include a radioactive sample having a decay rate capable of changing in response to interaction with a first particle or a field, and a detector associated with the radioactive sample. The detector is responsive to a second particle or radiation formed by decay of the radioactive sample. The rate of decay of the radioactive sample can be correlated to flux of the first particle or the field. Detection of the first particle or the field can provide an early warning for an impending solar event.

  11. The COMPASS event store

    CERN Document Server

    Duic, V; Fuchs, U; Gobbo, B; Lamanna, M; Martin, A; Nowak, M

    2004-01-01

    COMPASS, the fixed-target experiment at CERN studying the structure of the nucleon and spectroscopy, has collected over 500 TB during 2002 and 2003 runs. At the beginning of the experiment these data together with the reconstructed events information were put in a database infrastructure based on Objectivity/DB and on the hierarchical storage manager CASTOR. Starting from 2003 Oracle has been adopted as the database technology. The experience in the usage of the databases is reviewed, and the evolution of the system outlined.

  12. CATASTROPHIC EVENTS MODELING

    Directory of Open Access Journals (Sweden)

    Ciumas Cristina

    2013-07-01

    Full Text Available This paper presents the emergence and evolution of catastrophe models (cat models. Starting with the present context of extreme weather events and features of catastrophic risk (cat risk we’ll make a chronological illustration from a theoretical point of view of the main steps taken for building such models. In this way the importance of interdisciplinary can be observed. The first cat model considered contains three modules. For each of these indentified modules: hazard, vulnerability and financial losses a detailed overview and also an exemplification of a potential case of an earthquake that measures more than 7 on Richter scale occurring nowadays in Bucharest will be provided. The key areas exposed to earthquake in Romania will be identified. Then, based on past catastrophe data and taking into account present conditions of housing stock, insurance coverage and the population of Bucharest the impact will be quantified by determining potential losses. In order to accomplish this work we consider a scenario with data representing average values for: dwelling’s surface, location, finishing works. On each step we’ll make a reference to the earthquake on March 4 1977 to see what would happen today if a similar event occurred. The value of Bucharest housing stock will be determined taking firstly the market value, then the replacement value and ultimately the real value to quantify potential damages. Through this approach we can find the insurance coverage of potential losses and also the uncovered gap. A solution that may be taken into account by public authorities, for example by Bucharest City Hall will be offered: in case such an event occurs the impossibility of paying compensations to insured people, rebuilding infrastructure and public buildings and helping the suffering persons should be avoided. An actively public-private partnership should be created between government authorities, the Natural Disaster Insurance Pool, private

  13. Vaccine adverse events.

    Science.gov (United States)

    Follows, Jill

    2012-01-01

    Millions of adults are vaccinated annually against the seasonal influenza virus. An undetermined number of individuals will develop adverse events to the influenza vaccination. Those who suffer substantiated vaccine injuries, disabilities, and aggravated conditions may file a timely, no-fault and no-cost petition for financial compensation under the National Vaccine Act in the Vaccine Court. The elements of a successful vaccine injury claim are described in the context of a claim showing the seasonal influenza vaccination was the cause of Guillain-Barré syndrome.

  14. LIU 2011 event

    CERN Multimedia

    BE Department

    2011-01-01

    The LHC injectors upgrade (LIU) project was launched at the end of 2010 to coordinate the preparation of the CERN accelerator complex to meet the needs of the High Luminosity LHC (HL-LHC) until at least 2030. It should be completed by the end of the second long LHC shutdown, presently scheduled for 2018.   The goal of the LIU-2011 event is to present the status and plans of the LIU project, describing the needs and the actions foreseen in the different accelerators, from Linac4 to the PSB, PS and SPS.  

  15. Event Shape Sorting: selecting events with similar evolution

    Directory of Open Access Journals (Sweden)

    Tomášik Boris

    2017-01-01

    Full Text Available We present novel method for the organisation of events. The method is based on comparing event-by-event histograms of a chosen quantity Q that is measured for each particle in every event. The events are organised in such a way that those with similar shape of the Q-histograms end-up placed close to each other. We apply the method on histograms of azimuthal angle of the produced hadrons in ultrarelativsitic nuclear collisions. By selecting events with similar azimuthal shape of their hadron distribution one chooses events which are likely that they underwent similar evolution from the initial state to the freeze-out. Such events can more easily be compared to theoretical simulations where all conditions can be controlled. We illustrate the method on data simulated by the AMPT model.

  16. Talking about Causing Events

    Directory of Open Access Journals (Sweden)

    Christopher A. Vogel

    2014-12-01

    Full Text Available Questions about the nature of the relationship between language and extralinguistic cognition are old, but only recently has a new view emerged that allows for the systematic investigation of claims about linguistic structure, based on how it is understood or utilized outside of the language system. Our paper represents a case study for this interaction in the domain of event semantics. We adopt a transparency thesis about the relationship between linguistic structure and extralinguistic cognition, investigating whether different lexico-syntactic structures can differentially recruit the visual causal percept. A prominent analysis of causative verbs like move suggests reference to two distinct events and a causal relationship between them, whereas non-causative verbs like push do not so refer. In our study, we present English speakers with simple scenes that either do or do not support the perception of a causal link, and manipulate (between subjects a one-sentence instruction for the evaluation of the scene. Preliminary results suggest that competent speakers of English are more likely to judge causative constructions than non-causative constructions as true of a scene where causal features are present in the scene. Implications for a new approach to the investigation of linguistic meanings and future directions are discussed.

  17. The Pluto event generator

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Ingo [Institut fuer Kernphysik, 60438 Frankfurt am Main (Germany); Holzmann, Romain [Gesellschaft fuer Schwerionenphysik, 64291 Darmstadt (Germany)

    2008-07-01

    Pluto is a Monte-Carlo event generator designed for hadronic interactions from close-to-threshold to intermediate energies, as well as for studies of heavy ion reactions. The package is entirely based on Root, without the need of additional packages, and uses the embedded C++ interpreter of root to control the event production. The package includes realistic models of resonance production by using mass-dependent Breit-Wigner sampling. The calculation of partial and total widths for resonances is taken into account. Particular attention is paid to the electromagnetic decays, motivated by the physics program of HADES. For elementary reactions, angular distributions (e.g. for the primary meson emission) can be attached by the user in a very simple way as well as multi-particle correlations. Hand-made models (which may change all decay parameters) can be included by the user without recompilation using the CINT interpreter. This contribution gives an overview of the technical implementation of the framework and presents examples of the included physics.

  18. Fibrations of financial events

    CERN Document Server

    Carf\\i, David

    2011-01-01

    In this paper we shall prove that the plane of financial events, introduced and applied to financial problems by the author himself (see [2], [3] and [4]) can be considered as a fibration in two different ways. The first one, the natural one, reveals itself to be isomorphic to the tangent- bundle of the real line, when the last one is considered as a differentiable manifold in the natural way; the second one is a fibration induced by the status of compound interest capitalization at a given rate i in the interval ] - 1, \\rightarrow [. Moreover, in the paper we define on the first fibration an affine connection, also in this case induced by the status of compound interest at a given rate i. The final goal of this paper is the awareness that all the effects determined by the status of compound interest are nothing but the consequences of the fact that the space of financial events is a fibration endowed with a particular affine connection, so they are consequences of purely geometric properties, at last, depend...

  19. Solar Eruptive Events

    Science.gov (United States)

    Holman, Gordon D.

    2012-01-01

    It s long been known that the Sun plays host to the most energetic explosions in the solar system. But key insights into the forms that energy takes have only recently become available. Solar flares have been phenomena of both academic and practical interest since their discovery in 1859. From the academic point of view, they are the nearest events for studying the explosive release of energy in astrophysical magnetized plasmas. From the practical point of view, they disrupt communication channels on Earth, from telegraph communications in 1859 to radio and television signals today. Flares also wreak havoc on the electrical power grid, satellite operations, and GPS signals, and energetic charged particles and radiation are dangerous to passengers on high-altitude polar flights and to astronauts. Flares are not the only explosive phenomena on the Sun. More difficult to observe but equally energetic are the large coronal mass ejections (CMEs), the ejection of up to ten billion tons of magnetized plasma into the solar wind at speeds that can exceed 1000 km/s. CMEs are primarily observed from the side, with coronagraphs that block out the bright disk of the Sun and lower solar atmosphere so that light scattered from the ejected mass can be seen. Major geomagnetic storms are now known to arise from the interaction of CMEs with Earth's magnetosphere. Solar flares are observed without CMEs, and CMEs are observed without flares. The two phenomena often occur together, however, and almost always do in the case of large flares and fast CMEs. The term solar eruptive event refers to the combination of a flare and a CME. Solar eruptive events generate a lot of heat: They can heat plasma to temperatures as high at 50 million Kelvin, producing radiation across the electromagnetic spectrum. But that s not all. A fascinating aspect of solar eruptive events is the acceleration of electrons and ions to suprathermal often relativistic energies. The accelerated particles are primarily

  20. Uncovering undetected hypoglycemic events

    Directory of Open Access Journals (Sweden)

    Unger J

    2012-03-01

    Full Text Available Jeff UngerCatalina Research Institute, Chino, CA, USAAbstract: Hypoglycemia is the rate-limiting factor that often prevents patients with diabetes from safely and effectively achieving their glycemic goals. Recent studies have reported that severe hypoglycemia is associated with a significant increase in the adjusted risks of major macrovascular events, major microvascular events, and mortality. Minor hypoglycemic episodes can also have serious implications for patient health, psychological well being, and adherence to treatment regimens. Hypoglycemic events can impact the health economics of the patient, their employer, and third-party payers. Insulin treatment is a key predictor of hypoglycemia, with one large population-based study reporting an overall prevalence of 7.1% (type 1 diabetes mellitus and 7.3% (type 2 diabetes mellitus in insulin-treated patients, compared with 0.8% in patients with type 2 diabetes treated with an oral sulfonylurea. Patients with type 1 diabetes typically experience symptomatic hypoglycemia on average twice weekly and severe hypoglycemia once annually. The progressive loss of islet cell function in patients with type 2 diabetes results in a higher risk of both symptomatic and unrecognized hypoglycemia over time. Patients with diabetes who become hypoglycemic are also more susceptible to developing defective counter-regulation, also known as hypoglycemia awareness autonomic failure, which is life-threatening and must be aggressively addressed. In patients unable to recognize hypoglycemia symptoms, frequent home monitoring or use of continuous glucose sensors are critical. Primary care physicians play a key role in the prevention and management of hypoglycemia in patients with diabetes, particularly in those requiring intensive insulin therapy, yet physicians are often unaware of the multitude of consequences of hypoglycemia or how to deal with them. Careful monitoring, adherence to guidelines, and use of optimal

  1. Event-Based Conceptual Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    The paper demonstrates that a wide variety of event-based modeling approaches are based on special cases of the same general event concept, and that the general event concept can be used to unify the otherwise unrelated fields of information modeling and process modeling. A set of event......-based modeling approaches are analyzed and the results are used to formulate a general event concept that can be used for unifying the seemingly unrelated event concepts. Events are characterized as short-duration processes that have participants, consequences, and properties, and that may be modeled in terms...... of information structures. The general event concept can be used to guide systems analysis and design and to improve modeling approaches....

  2. Coping with a Traumatic Event

    Science.gov (United States)

    ... Traumatic events are marked by a sense of horror, helplessness, serious injury, or the threat of serious ... the number of times an event happened, a history of past trauma, and psychological problems before the ...

  3. The Infinite Latent Events Model

    CERN Document Server

    Wingate, David; Roy, Daniel; Tenenbaum, Joshua

    2012-01-01

    We present the Infinite Latent Events Model, a nonparametric hierarchical Bayesian distribution over infinite dimensional Dynamic Bayesian Networks with binary state representations and noisy-OR-like transitions. The distribution can be used to learn structure in discrete timeseries data by simultaneously inferring a set of latent events, which events fired at each timestep, and how those events are causally linked. We illustrate the model on a sound factorization task, a network topology identification task, and a video game task.

  4. Extreme Energy Events Monitoring report

    CERN Document Server

    Baimukhamedova, Nigina

    2015-01-01

    Following paper reflects the progress I made on Summer Student Program within Extreme Energy Events Monitor project I was working on. During 8 week period I managed to build a simple detector system that is capable of triggering events similar to explosions (sudden change in sound levels) and measuring approximate location of the event. Source codes are available upon request and settings described further.

  5. Stimuli, Reinforcers, and Private Events

    Science.gov (United States)

    Nevin, John A.

    2008-01-01

    Radical behaviorism considers private events to be a part of ongoing observable behavior and to share the properties of public events. Although private events cannot be measured directly, their roles in overt action can be inferred from mathematical models that relate private responses to external stimuli and reinforcers according to the same…

  6. Event boundaries and memory improvement.

    Science.gov (United States)

    Pettijohn, Kyle A; Thompson, Alexis N; Tamplin, Andrea K; Krawietz, Sabine A; Radvansky, Gabriel A

    2016-03-01

    The structure of events can influence later memory for information that is embedded in them, with evidence indicating that event boundaries can both impair and enhance memory. The current study explored whether the presence of event boundaries during encoding can structure information to improve memory. In Experiment 1, memory for a list of words was tested in which event structure was manipulated by having participants walk through a doorway, or not, halfway through the word list. In Experiment 2, memory for lists of words was tested in which event structure was manipulated using computer windows. Finally, in Experiments 3 and 4, event structure was manipulated by having event shifts described in narrative texts. The consistent finding across all of these methods and materials was that memory was better when the information was distributed across two events rather than combined into a single event. Moreover, Experiment 4 demonstrated that increasing the number of event boundaries from one to two increased the memory benefit. These results are interpreted in the context of the Event Horizon Model of event cognition.

  7. EVENT PLANNING USING FUNCTION ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Lori Braase; Jodi Grgich

    2011-06-01

    Event planning is expensive and resource intensive. Function analysis provides a solid foundation for comprehensive event planning (e.g., workshops, conferences, symposiums, or meetings). It has been used at Idaho National Laboratory (INL) to successfully plan events and capture lessons learned, and played a significant role in the development and implementation of the “INL Guide for Hosting an Event.” Using a guide and a functional approach to planning utilizes resources more efficiently and reduces errors that could be distracting or detrimental to an event. This integrated approach to logistics and program planning – with the primary focus on the participant – gives us the edge.

  8. The Chelyabinsk event

    Science.gov (United States)

    Borovička, Jiří

    2016-10-01

    On February 15, 2013, 3:20 UT, an asteroid of the size of about 19 meters and mass of 12,000 metric tons entered the Earth's atmosphere unexpectedly near the border of Kazakhstan and Russia. It was the largest confirmed Earth impactor since the Tunguska event in 1908. The body moved approximately westwards with a speed of 19 km s-1, on a trajectory inclined 18 degrees to the surface, creating a fireball of steadily increasing brightness. Eleven seconds after the first sightings, the fireball reached its maximum brightness. At that point, it was located less than 40 km south from Chelyabinsk, a Russian city of population more than one million, at an altitude of 30 km. For people directly underneath, the fireball was 30 times brighter than the Sun. The cosmic body disrupted into fragments; the largest of them was visible for another five seconds before it disappeared at an altitude of 12.5 km, when it was decelerated to 3 km s-1. Fifty six second later, that ~600 kg fragment landed in Lake Chebarkul and created a 8 m wide hole in the ice. Small meteorites landed in an area 80 km long and several km wide and caused no damage. The meteorites were classified as LL ordinary chondrites and were interesting by the presence of two phases, light and dark. More material remained, however, in the atmosphere forming a dust trail up to 2 km wide and extending along the fireball trajectory from altitude 18 to 70 km. The dust then circled the Earth within few days and formed a ring around the northern hemisphere. In Chelyabinsk and its surroundings a very strong blast wave arrived 90 - 150 s after the fireball passage (depending on location). The wave was produced by the supersonic flight of the body and broke ~10% of windows in Chelyabinsk (~40% of buildings were affected). More than 1600 people were injured, mostly from broken glass. The whole event was well documented by video cameras, seismic and infrasonic records, and satellite observations. The total energy was 500 kT TNT

  9. Dynamical freeze-out in event-by-event hydrodynamics

    CERN Document Server

    Holopainen, Hannu

    2012-01-01

    In hydrodynamical modeling of the ultrarelativistic heavy-ion collisions the freeze-out is typically performed at a constant temperature or density. In this work we apply a dynamical freeze-out criterion, which compares the hydrodynamical expansion rate with the pion scattering rate. Recently many calculations have been done using event-by-event hydrodynamics where the initial density profile fluctuates from event to event. In these event-by-event calculations the expansion rate fluctuates strongly as well, and thus it is interesting to check how the dynamical freeze-out changes hadron distributions with respect to the constant temperature freeze-out. We present hadron spectra and elliptic flow calculated using (2+1)-dimensional ideal hydrodynamics, and show the differences between constant temperature and dynamical freeze-out criteria. We find that the differences caused by different freeze-out criteria are small in all studied cases.

  10. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. Zoom into the tracking detector and the LAr calorimeter where its detailed structure is highlighted. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  11. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  12. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. Zoom into the tracking detector. The tracks and clusters of the two electron pairs are colored red and blue, respectively.

  13. Event shape based global event cuts for the LHCb trigger

    CERN Document Server

    Kolchanova, Alena; CERN. Geneva. Department

    2016-01-01

    In 2019 LHCb will have one of the biggest upgrades of all LHC experiments. The project aims to study event shape variables for the LHCb trigger. Event shape variables are used to help identify events as having a higher likelihood of containing a beauty hadron within the LHCb acceptance from Minimum bias. Samples of each process are generated using the Pythia program. Fox Wolfram Moments, sphericity and thrust are applied to the data by selecting events with pseudorapidity $2.2 $ 2 GeV.

  14. Significant Tsunami Events

    Science.gov (United States)

    Dunbar, P. K.; Furtney, M.; McLean, S. J.; Sweeney, A. D.

    2014-12-01

    Tsunamis have inflicted death and destruction on the coastlines of the world throughout history. The occurrence of tsunamis and the resulting effects have been collected and studied as far back as the second millennium B.C. The knowledge gained from cataloging and examining these events has led to significant changes in our understanding of tsunamis, tsunami sources, and methods to mitigate the effects of tsunamis. The most significant, not surprisingly, are often the most devastating, such as the 2011 Tohoku, Japan earthquake and tsunami. The goal of this poster is to give a brief overview of the occurrence of tsunamis and then focus specifically on several significant tsunamis. There are various criteria to determine the most significant tsunamis: the number of deaths, amount of damage, maximum runup height, had a major impact on tsunami science or policy, etc. As a result, descriptions will include some of the most costly (2011 Tohoku, Japan), the most deadly (2004 Sumatra, 1883 Krakatau), and the highest runup ever observed (1958 Lituya Bay, Alaska). The discovery of the Cascadia subduction zone as the source of the 1700 Japanese "Orphan" tsunami and a future tsunami threat to the U.S. northwest coast, contributed to the decision to form the U.S. National Tsunami Hazard Mitigation Program. The great Lisbon earthquake of 1755 marked the beginning of the modern era of seismology. Knowledge gained from the 1964 Alaska earthquake and tsunami helped confirm the theory of plate tectonics. The 1946 Alaska, 1952 Kuril Islands, 1960 Chile, 1964 Alaska, and the 2004 Banda Aceh, tsunamis all resulted in warning centers or systems being established.The data descriptions on this poster were extracted from NOAA's National Geophysical Data Center (NGDC) global historical tsunami database. Additional information about these tsunamis, as well as water level data can be found by accessing the NGDC website www.ngdc.noaa.gov/hazard/

  15. Tidal disruption event demographics

    Science.gov (United States)

    Kochanek, C. S.

    2016-09-01

    We survey the properties of stars destroyed in tidal disruption events (TDEs) as a function of black hole (BH) mass, stellar mass and evolutionary state, star formation history and redshift. For M_{BH} ≲ 10^7 M_{⊙}, the typical TDE is due to a M* ˜ 0.3 M⊙ M-dwarf, although the mass function is relatively flat for M_{ast } ≲ M_{⊙}. The contribution from older main-sequence stars and sub-giants is small but not negligible. From MBH ≃ 107.5-108.5 M⊙, the balance rapidly shifts to higher mass stars and a larger contribution from evolved stars, and is ultimately dominated by evolved stars at higher BH masses. The star formation history has little effect until the rates are dominated by evolved stars. TDE rates should decline very rapidly towards higher redshifts. The volumetric rate of TDEs is very high because the BH mass function diverges for low masses. However, any emission mechanism which is largely Eddington-limited for low BH masses suppresses this divergence in any observed sample and leads to TDE samples dominated by MBH ≃ 106.0-107.5 M⊙ BHs with roughly Eddington peak accretion rates. The typical fall-back time is relatively long, with 16 per cent having tfb plausible if tfb has any relation to the transient rise time. For almost any BH mass function, systematic searches for fainter, faster time-scale TDEs in smaller galaxies, and longer time-scale TDEs in more massive galaxies are likely to be rewarded.

  16. Event-by-event simulation of quantum phenomena

    NARCIS (Netherlands)

    De Raedt, Hans; Michielsen, Kristel

    2012-01-01

    A discrete-event simulation approach is reviewed that does not require the knowledge of the solution of the wave equation of the whole system, yet reproduces the statistical distributions of wave theory by generating detection events one-by-one. The simulation approach is illustrated by applications

  17. Event-by-event simulation of quantum phenomena

    NARCIS (Netherlands)

    De Raedt, H.; Zhao, S.; Yuan, S.; Jin, F.; Michielsen, K.; Miyashita, S.

    2010-01-01

    We discuss recent progress in the development of simulation algorithms that do not rely on any concept of quantum theory but are nevertheless capable of reproducing the averages computed from quantum theory through an event-by-event simulation. The simulation approach is illustrated by applications

  18. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks and clusters of the two electron pairs are colored red and blue, respectively. The three displays on the right-hand side show the r-phi view of the event (top), a zoom into the vertex region, indicating that the 4 electrons originate from the same primary vertex (middle), and a Lego plot indicating the amount of transverse energy Et measured in the calorimeters (bottom).

  19. Event display of a H -> 4e candidate event

    CERN Multimedia

    ATLAS, Collaboration

    2012-01-01

    Event display (side view) of a H -> 4e candidate event with m(4l) = 124.5 (124.6) GeV without (with) Z mass constraint. The masses of the lepton pairs are 70.6 GeV and 44.7 GeV. The event was recorded by ATLAS on 18-May-2012, 20:28:11 CEST in run number 203602 as event number 82614360. The tracks of the two electron pairs are colored red and blue, respectively. Electron clusters in the LAr calorimeter are colored darkgreen. The three displays on the right-hand side show the r-phi view of the event (top), a zoom into the vertex region, indicating that the 4 electrons originate from the same primary vertex (middle), and a Lego plot indicating the amount of transverse energy Et measured in the calorimeters (bottom).

  20. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...

  1. Generator for Centauro Event Simulation

    CERN Document Server

    Gladysz-Dziadus, E; Panagiotou, A D; Sadovsky, S A

    1998-01-01

    We present a first generator of Centauro events based on the phenomenological model of Panagiotou et al. and show the quantitative consequences for kinematics, baryon number, mass and decay properties of the Centauro fireball and the strange quark matter fireball produced in ion collisions according to the Centauro event scenario.

  2. Event-Based Activity Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2004-01-01

    We present and discuss a modeling approach that supports event-based modeling of information and activity in information systems. Interacting human actors and IT-actors may carry out such activity. We use events to create meaningful relations between information structures and the related activit...

  3. Eventos de Junio (June Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains brief information on six June events celebrated by Puerto Ricans: Nathan Hale, Dia de la Bandera (Flag Day), Francisco Oller, Dia de los Padres (Father's Day), Fiesta de San Juan Bautista, and school graduation. Designed for teachers, the booklet includes a listing of 16 historical events occurring in…

  4. Maternal Talk About Disappearance Events.

    Science.gov (United States)

    Goldfield, Beverly A.

    1995-01-01

    Examined maternal talk about events regarding hidden, missing, or absent persons or objects, and the relationship of maternal language to children's acquisition of words for disappearance, among 12 mother-infant pairs. Results found that infants who had acquired "gone" and similar terms experienced more disappearance events than children…

  5. ATLAS simulated black hole event

    CERN Multimedia

    Pequenão, J

    2008-01-01

    The simulated collision event shown is viewed along the beampipe. The event is one in which a microscopic-black-hole was produced in the collision of two protons (not shown). The microscopic-black-hole decayed immediately into many particles. The colors of the tracks show different types of particles emerging from the collision (at the center).

  6. Regularly timed events amid chaos

    Science.gov (United States)

    Blakely, Jonathan N.; Cooper, Roy M.; Corron, Ned J.

    2015-11-01

    We show rigorously that the solutions of a class of chaotic oscillators are characterized by regularly timed events in which the derivative of the solution is instantaneously zero. The perfect regularity of these events is in stark contrast with the well-known unpredictability of chaos. We explore some consequences of these regularly timed events through experiments using chaotic electronic circuits. First, we show that a feedback loop can be implemented to phase lock the regularly timed events to a periodic external signal. In this arrangement the external signal regulates the timing of the chaotic signal but does not strictly lock its phase. That is, phase slips of the chaotic oscillation persist without disturbing timing of the regular events. Second, we couple the regularly timed events of one chaotic oscillator to those of another. A state of synchronization is observed where the oscillators exhibit synchronized regular events while their chaotic amplitudes and phases evolve independently. Finally, we add additional coupling to synchronize the amplitudes, as well, however in the opposite direction illustrating the independence of the amplitudes from the regularly timed events.

  7. Extinction Events Can Accelerate Evolution

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific......Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate...... evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending...

  8. Extinction events can accelerate evolution.

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    Full Text Available Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term.

  9. Extinction Events Can Accelerate Evolution

    Science.gov (United States)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term. PMID:26266804

  10. Event extraction for DNA methylation

    Directory of Open Access Journals (Sweden)

    Ohta Tomoko

    2011-10-01

    Full Text Available Abstract Background We consider the task of automatically extracting DNA methylation events from the biomedical domain literature. DNA methylation is a key mechanism of epigenetic control of gene expression and implicated in many cancers, but there has been little study of automatic information extraction for DNA methylation. Results We present an annotation scheme for DNA methylation following the representation of the BioNLP shared task on event extraction, select a set of 200 abstracts including a representative sample of all PubMed citations relevant to DNA methylation, and introduce manual annotation for this corpus marking nearly 3000 gene/protein mentions and 1500 DNA methylation and demethylation events. We retrain a state-of-the-art event extraction system on the corpus and find that automatic extraction of DNA methylation events, the methylated genes, and their methylation sites can be performed at 78% precision and 76% recall. Conclusions Our results demonstrate that reliable extraction methods for DNA methylation events can be created through corpus annotation and straightforward retraining of a general event extraction system. The introduced resources are freely available for use in research from the GENIA project homepage http://www-tsujii.is.s.u-tokyo.ac.jp/GENIA.

  11. Formalization of Event Perception and Event Appraisal Process

    Directory of Open Access Journals (Sweden)

    Shikha Jain

    2015-06-01

    Full Text Available Integration of emotion in a virtual agent is a topic of research to depict human-like behavior in a simulated environment. For the last few decades, many researchers are working in the field of incorporating emotions in a virtual agent. In the emotion model, the behavior of an agent depends upon how the event is perceived by the agent with respect to the goal. Hence, perception of the event while considering the past experience, importance of event towards achieving goal, agent’s own capabilities and resources is an important process which directly influences the decision making and action selection. The proposed models, till date, are either too complex to adapt or are using a very few parameters to describe the event. So, in this paper, we propose an extension of perception process in an existing emotion model, EMIA and suggest the formalization of event perception and appraisal processes to make it adaptable. This has been carried out using five parameters for event description along-with fuzzy logic which makes the process more effective yet simple.

  12. Event Display for the Visualization of CMS Events

    Science.gov (United States)

    Bauerdick, L. A. T.; Eulisse, G.; Jones, C. D.; Kovalskyi, D.; McCauley, T.; Mrak Tadel, A.; Muelmenstaedt, J.; Osborne, I.; Tadel, M.; Tu, Y.; Yagil, A.

    2011-12-01

    During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.

  13. Event Displays for the Visualization of CMS Events

    CERN Document Server

    Jones, Christopher Duncan

    2010-01-01

    During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.

  14. Organizational Learning in Rare Events

    DEFF Research Database (Denmark)

    Vaarst Andersen, Kristina; Beukel, Karin; Tyler, Beverly B.

    When organizations encounter rare events they often find it challenging to extract learning from the experience. We analyze opportunities for organizational learning in one such rare event, namely Intellectual Property (IP) litigation, i.e., when organizations take disputes regarding...... their intellectual property to court. We propose, that organizations can learn to litigate, although it is a rare event, by applying mechanisms in a current litigation case that have been successful in previous litigation cases. However, we also posit, that the usefulness of these learning mechanisms for a current...

  15. Early traumatic events in psychopaths.

    Science.gov (United States)

    Borja, Karina; Ostrosky, Feggy

    2013-07-01

    The relationship between diverse early traumatic events and psychopathy was studied in 194 male inmates. Criminal history transcripts were revised, and clinical interviews were conducted to determine the level of psychopathy using the Psychopathy Checklist-Revised (PCL-R) Form, and the Early Trauma Inventory was applied to assess the incidence of abuse before 18 years of age. Psychopathic inmates presented a higher victimization level and were more exposed to certain types of intended abuse than sociopathic inmates, while the sum of events and emotional abuse were associated with the PCL-R score. Our studies support the influence of early adverse events in the development of psychopathic offenders.

  16. Adverse Event Reporting System (AERS)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Adverse Event Reporting System (AERS) is a computerized information database designed to support the FDA's post-marketing safety surveillance program for all...

  17. Event Reports for Operating Reactors

    Data.gov (United States)

    Nuclear Regulatory Commission — Raw data of all the events for the last month. Raw data is presented in pipe delimited format. This data set is updated monthly on the first business day of the month.

  18. MGR External Events Hazards Analysis

    Energy Technology Data Exchange (ETDEWEB)

    L. Booth

    1999-11-06

    The purpose and objective of this analysis is to apply an external events Hazards Analysis (HA) to the License Application Design Selection Enhanced Design Alternative 11 [(LADS EDA II design (Reference 8.32))]. The output of the HA is called a Hazards List (HL). This analysis supersedes the external hazards portion of Rev. 00 of the PHA (Reference 8.1). The PHA for internal events will also be updated to the LADS EDA II design but under a separate analysis. Like the PHA methodology, the HA methodology provides a systematic method to identify potential hazards during the 100-year Monitored Geologic Repository (MGR) operating period updated to reflect the EDA II design. The resulting events on the HL are candidates that may have potential radiological consequences as determined during Design Basis Events (DBEs) analyses. Therefore, the HL that results from this analysis will undergo further screening and analysis based on the criteria that apply during the performance of DBE analyses.

  19. Underlying Event Studies at RHIC

    CERN Document Server

    Caines, Helen

    2009-01-01

    By studying p-p collisions we hope to improve our understanding of the fundamental constituents of matter and how they form into colorless objects. Measurements of the inclusive jet cross-sections and fragmentation properties have confirmed that QCD based calculations give a good description of the hard scattering processes. However, as our analysis of jets has improved it has become clear that there is significant contribution to these measurements from processes other than those directly related to the initial hard scattering - the so-called underlying event. Several processes contribute to the underlying event, namely the beam-beam remnants, initial and final state radiation and multiple parton interactions. The structure of the jet and the underlying event are strikingly different in both their particle compositions and momentum distributions. Only by understanding both components can one fully describe a p-p collision. I will discuss preliminary results from studies of the underlying event in p-p collisi...

  20. Brief resolved unexplained event - BRUE

    Science.gov (United States)

    ... terms such as "near-miss SIDS" or "aborted crib deaths," which are no longer used. Events that involve ... BRUE is unlikely to be a risk for sudden infant death syndrome (SIDS). Most victims of SIDS do not ...

  1. Discrete Event Programming with Simkit

    OpenAIRE

    Buss, Arnold

    2001-01-01

    This paper is a brief introduction to the use of Simkit, a software package for implementing Discrete Event Simulation (DES) models. Simkit is written in Java (for any operating system with Java 2TM ).

  2. Events i den globale bykonkurrence

    DEFF Research Database (Denmark)

    Østergaard, Katrine

    2005-01-01

    Paper til ph.d. workshop, d. 9. december 2005. Dette paper beskriver, hvorfor og hvordan events kan bruges som strategi for byplanlægning og byudvikling i den globale bykonkurrence.......Paper til ph.d. workshop, d. 9. december 2005. Dette paper beskriver, hvorfor og hvordan events kan bruges som strategi for byplanlægning og byudvikling i den globale bykonkurrence....

  3. Recent measurement of underlying events

    CERN Document Server

    Wang, Wei Yang

    2016-01-01

    Recent measurements on the underlying events (UE) in the event topology of leading jet and leading track are presented. UE activities are quantified in term of particle and energy density. The UE observables are calculated in the transverse region with respect to the direction highest pT jet/track. These UE observables are measured as a as function of the pT of the leading track and jet.

  4. Ordovician chitinozoan diversification events in China

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiaofeng; CHEN; Xiaohong

    2004-01-01

    Correlative study of the Ordovician chitinozoan biostratigraphy in China with graptolite and conodont biozones, and comprehensive analysis of the sequence- and event-stratigraphic indicated that 17 chitinozoan zones and 5 main chitinozoan diversification events subsequently occurring could be recognized in the Ordovician System of China. The 5 events comprise: event 1-appearance of the earliest Ordovician chitinozoans, event 2-appearance of C. symmetrica, event 3-juvenile radiation of chitinozoans, event 4-appearance of chitinozoans with high diversity, and event 5-development of chitinozoans of deep-water facies. The age and feature of each event and its relation with the sea-level change and other geological event are discussed.

  5. Superstatistics and renewal critical events

    Science.gov (United States)

    Paradisi, Paolo; Cesari, Rita; Grigolini, Paolo

    2009-09-01

    An approach to intermittent systems based on renewal processes is reviewed. The Waiting Times (WTs) between events are the main variables of interest in intermittent systems. A crucial role is played by the class of critical events, characterized by Non-Poisson statistics and non-exponential WT distribution. A particular important case is given by WT distributions with power tail. Critical events play a crucial role in the behavior of a property known as Renewal Aging. Focusing on the role of critical events, the relation between superstatistics and non-homogeneous Poisson processes is discussed, and the role of Renewal Aging is illustrated by comparing a Non-Poisson model with a Poisson one, both of them modulated by a periodic forcing. It is shown that the analysis of Renewal Aging is sensitive to the presence of critical events and that this property can be exploited to detect Non-Poisson statistics in a time series. As a consequence, it is claimed that, apart from the characterization of superstatistical features such as the distribution of the intensive parameter or the separation of the time scales, the Renewal Aging property can give some effort to better determine the role of Non-Poisson critical events in intermittent systems.

  6. Modeling Documents with Event Model

    Directory of Open Access Journals (Sweden)

    Longhui Wang

    2015-08-01

    Full Text Available Currently deep learning has made great breakthroughs in visual and speech processing, mainly because it draws lessons from the hierarchical mode that brain deals with images and speech. In the field of NLP, a topic model is one of the important ways for modeling documents. Topic models are built on a generative model that clearly does not match the way humans write. In this paper, we propose Event Model, which is unsupervised and based on the language processing mechanism of neurolinguistics, to model documents. In Event Model, documents are descriptions of concrete or abstract events seen, heard, or sensed by people and words are objects in the events. Event Model has two stages: word learning and dimensionality reduction. Word learning is to learn semantics of words based on deep learning. Dimensionality reduction is the process that representing a document as a low dimensional vector by a linear mode that is completely different from topic models. Event Model achieves state-of-the-art results on document retrieval tasks.

  7. Causal events enter awareness faster than non-causal events

    Science.gov (United States)

    Wagemans, Johan; de-Wit, Lee

    2017-01-01

    Philosophers have long argued that causality cannot be directly observed but requires a conscious inference (Hume, 1967). Albert Michotte however developed numerous visual phenomena in which people seemed to perceive causality akin to primary visual properties like colour or motion (Michotte, 1946). Michotte claimed that the perception of causality did not require a conscious, deliberate inference but, working over 70 years ago, he did not have access to the experimental methods to test this claim. Here we employ Continuous Flash Suppression (CFS)—an interocular suppression technique to render stimuli invisible (Tsuchiya & Koch, 2005)—to test whether causal events enter awareness faster than non-causal events. We presented observers with ‘causal’ and ‘non-causal’ events, and found consistent evidence that participants become aware of causal events more rapidly than non-causal events. Our results suggest that, whilst causality must be inferred from sensory evidence, this inference might be computed at low levels of perceptual processing, and does not depend on a deliberative conscious evaluation of the stimulus. This work therefore supports Michotte’s contention that, like colour or motion, causality is an immediate property of our perception of the world. PMID:28149698

  8. The ATLAS Event Service: A New Approach to Event Processing

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00070566; De, Kaushik; Guan, Wen; Maeno, Tadashi; Nilsson, Paul; Oleynik, Danila; Panitkin, Sergey; Tsulaia, Vakhtang; van Gemmeren, Peter; Wenaus, Torre

    2015-01-01

    The ATLAS Event Service (ES) implements a new fine grained approach to HEP event processing, designed to be agile and efficient in exploiting transient, short-lived resources such as HPC hole-filling, spot market commercial clouds, and volunteer computing. Input and output control and data flows, bookkeeping, monitoring, and data storage are all managed at the event level in an implementation capable of supporting ATLAS-scale distributed processing throughputs (about 4M CPU-hours/day). Input data flows utilize remote data repositories with no data locality or pre­staging requirements, minimizing the use of costly storage in favor of strongly leveraging powerful networks. Object stores provide a highly scalable means of remotely storing the quasi-continuous, fine grained outputs that give ES based applications a very light data footprint on a processing resource, and ensure negligible losses should the resource suddenly vanish. We will describe the motivations for the ES system, its unique features and capabi...

  9. Bayesian analysis of rare events

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Daniel, E-mail: straub@tum.de; Papaioannou, Iason; Betz, Wolfgang

    2016-06-01

    In many areas of engineering and science there is an interest in predicting the probability of rare events, in particular in applications related to safety and security. Increasingly, such predictions are made through computer models of physical systems in an uncertainty quantification framework. Additionally, with advances in IT, monitoring and sensor technology, an increasing amount of data on the performance of the systems is collected. This data can be used to reduce uncertainty, improve the probability estimates and consequently enhance the management of rare events and associated risks. Bayesian analysis is the ideal method to include the data into the probabilistic model. It ensures a consistent probabilistic treatment of uncertainty, which is central in the prediction of rare events, where extrapolation from the domain of observation is common. We present a framework for performing Bayesian updating of rare event probabilities, termed BUS. It is based on a reinterpretation of the classical rejection-sampling approach to Bayesian analysis, which enables the use of established methods for estimating probabilities of rare events. By drawing upon these methods, the framework makes use of their computational efficiency. These methods include the First-Order Reliability Method (FORM), tailored importance sampling (IS) methods and Subset Simulation (SuS). In this contribution, we briefly review these methods in the context of the BUS framework and investigate their applicability to Bayesian analysis of rare events in different settings. We find that, for some applications, FORM can be highly efficient and is surprisingly accurate, enabling Bayesian analysis of rare events with just a few model evaluations. In a general setting, BUS implemented through IS and SuS is more robust and flexible.

  10. Events

    Directory of Open Access Journals (Sweden)

    Marina Tkacheva

    2010-12-01

    Full Text Available Baikal Economic ForumInternational Scientific and Practical Conference"Culture of Wood - Wood in Culture"Summer Ateliers of UrbanistsMemorandum of Understanding between UIA and Active House AllianceKorean Team Wins the First Prize in the VELUX AwardUIA Professional Practice Commission"Zodchestvo 2010" International FestivalRainbow of "Zodchestvo 2010" in ManezhThree Opinions on One Book about Gogol's Two"Soviet Modernism" BookV Plenum of the Board of the Union of Architects of RussiaXXX Meeting of Chief ArchitectsCompetition of Graduation ProjectsInternational Day of Architecture

  11. Events

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2015-12-01

    Full Text Available In April 2015 a charity program “PROTECTED AREAS – LIFE SAVER” was launched for reserved areas and national parks in Russia and CIS countries. The project “Eagles of Russia” received the support of the Russian Geographical Society for the second time.  In 2015 in the Republic of Tatarstan 67 special protection forest areas (SPFA will be allotted in 17 administrative districts. Where there will be 41 areas for the protection of the Imperial Eagle (Aquila heliaca, 23 – for the White-Tailed Eagle (Haliaeetus albicilla and 3 – for the Greater Spotted Eagle (Aquila clanga. XIV International Ornithological Conference of Northern Eurasia was held in August 18–24, 2015 in Almaty, Kazakhstan, on the basis of Kazakh National University named after Al-Farabi (KNU. V International readings from Buturlin, dedicated to the memory of Sergei Buturlin a famous Russian ornithologist, were held in September 22–24,2015 inUlyanovsk. In 29–30 October 2015, the Interregional Conference “Raptor Research and Conservation. Legislative Issue” was held in Elista. The status of steppe eagle (Aquila nipalensis in the European Red List and IUCN Red List has changed. SochiNational Park, Southern Federal University, Menzbir Ornithological Society and the Working Group on birds of prey and owls of Northern Eurasia are planning to hold regular VII International Conference on research and conservation of raptors in North Eurasia inSochion the basis of theSochiNational Park. Excerpts from the Resolution Adopted at the XIV International Ornithological Conference ofNorth Eurasia. Date held: 18–22 August, 2015. Excerpts from the Resolution Adopted at the Interregional Conference “Raptor Research and Conservation. Legislative Issue”. Date held: 29–30 October, 2015.

  12. EVENTS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Car insurers suffered loss in discount wars A senior official told a conference on Feb 17 that insurers in Beijing Suffered around 700 million yuan loss in 2008 due to discount wars among insurers."They suffered great losses and unwilling to compensate the damages as a result,"said Liu Yuelin,assistant chief of

  13. Event

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>STEL LALUNA 201 1秋冬时尚发表会时尚女鞋天后STELLA LUNA 2011秋冬时尚发表会在上海隆重献演,本季秀场选址为黄浦江畔的世博水门码头盛大举行,聚集全球嘉宾与时尚媒体,宣告今年时尚十足的流行趋势。身为STELLA LUNA的狂热追随者,董璇、黄奕等嘉宾现场演绎STELLA LUNA秋冬时尚风采,再一次证明穿STELLA LUNA的女人果然具有猎捕无数摄影镜头的惊人能力。

  14. Events

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2015-12-01

    Full Text Available On the April 8-10 of 2014 an International Conference “Birds of Prey in the North Caucasus and Adjacent Regions: distribution, ecology, population dynamics, protection” was held in Sochi National Park, Sochi, Russia. The Saker Falcon Falco cherrug Global Action Plan (SakerGAP has been presented at the 11th Meeting of the Parties of the Bonn Convention (CMS, which took place in Quito (Ecuador on 4-9 November 2014. On the December 17 of 2014 a meeting between inspectors of Nature Reserve “Khakasskiy”, police of Khakasia Republic and experts of Siberian Environmental Center was held in the Nature Reserve “Khakasskiy”. On the December 20 of 2014 an annual meeting of members of Siberian Environmental Center (SEC was held in Akademgorodok, Novosibirsk, Russia. Project leaders presented reports on the main activities and achievements gained in 2014. The Long-eared Owl (Asio otus became the Bird of the Year announced by the public organization "APB-BirdLife Belarus". The 9th ARRCN Symposium 2015 will be held during 21st–25th October 2015 at the Novotel Hotel, Chumphon, Thailand, one of the most favored travel destinations in Asia.

  15. Trending analysis of precursor events

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-01-01

    The Accident Sequence Precursor (ASP) Program of United States Nuclear Regulatory Commission (U.S.NRC) identifies and categorizes operational events at nuclear power plants in terms of the potential for core damage. The ASP analysis has been performed on yearly basis and the results have been published in the annual reports. This paper describes the trends in initiating events and dominant sequences for 459 precursors identified in the ASP Program during the 1969-94 period and also discusses a comparison with dominant sequences predicted in the past Probabilistic Risk Assessment (PRA) studies. These trends were examined for three time periods, 1969-81, 1984-87 and 1988-94. Although the different models had been used in the ASP analyses for these three periods, the distribution of precursors by dominant sequences show similar trends to each other. For example, the sequences involving loss of both main and auxiliary feedwater were identified in many PWR events and those involving loss of both high and low coolant injection were found in many BWR events. Also, it was found that these dominant sequences were comparable to those determined to be dominant in the predictions by the past PRAs. As well, a list of the 459 precursors identified are provided in Appendix, indicating initiating event types, unavailable systems, dominant sequences, conditional core damage probabilities, and so on. (author)

  16. OMS event evaluator and scheduler

    Science.gov (United States)

    Eckelkamp, Richard E.

    1990-01-01

    An Operations Management System (OMS) is being designed for Space Station Freedom to improve productivity, reliability, and safety while reducing operations and maintenance costs. Central to the concept is a short term plan containing mixes of man-readable and machine-executable procedures used in an environment of distributed processing and execution. An OMS event evaluator to check upcoming short-term plan events for validity of execution is under development. The first version checks time and resource constraints against operational conditions for current or expected stations. In work are the handling of environmental and other operational constraints, as well as detailed modeling of resources and station operational states. The Ada Program also has the ability to reschedule all or part of the events.

  17. The public of media events

    Directory of Open Access Journals (Sweden)

    Christian Morgner

    2010-12-01

    Full Text Available This article focuses on the growing importance of large-scale events and their central role in a globalised media world in relation to public reactions and public involvement. The peculiar structure of such events requires a different understanding of mass communication and its audience. Therefore, the audience is further examined with regard to its impact on and inclusion in the media itself. Consequently, questions are raised as to how the public is incorporated, the form this inclusion takes and the effect that this has on the audience’s participation.The article examines different types of semantic inclusion, with a focus on emotional reactions towards three different media events: the Titanic disaster, the assassination of John F. Kennedy, and the death of Princess Diana.

  18. CRITICAL EVENTS IN CONSTRUCTION PROCESS

    DEFF Research Database (Denmark)

    Jørgensen, Kirsten; Rasmussen, Grane Mikael Gregaard

    2009-01-01

    Function failures, defects and poor communication are major problems in the construction industry. These failures and defects are caused by a row of critical events in the construction process. The purpose of this paper is to define “critical events” in the construction process and to investigate...... cause-effects of failures and defects in the construction industry by using an analytical approach (The bowtie model) which is developed in the accident research. Using this model clarifies the relationships within the chain of failures that causes critical events with undesirable consequences....... In this way the causes of failures and the relationships between various failures are rendered visible. A large construction site was observed from start to finish as the empirical element in the research. The research focuses on all kinds of critical events identified throughout every phase during...

  19. International Sport Events: Improving Marketing

    Directory of Open Access Journals (Sweden)

    Margarita Kerzaitė

    2014-04-01

    Full Text Available The report and the article will be a comprehensive analysis ofthe needs to improve the international sport events marketing.Highlighting the role of international sport events in contemporarysociety and the challenges in the context of globalization,comparing opinions of various authors about aspects of classificationand the benefits for host country. The article and the reportreveals the main existing problem encountered in organizinginternational sport events, estimated perspectives for solutionof this problem. Summarizes the international sport eventsopportunities, basically modernize marketing tools according tothe marketing mix correction based on systematic synthesis ofmarketing concepts and adaptation/standardization needs, themost important factors in the marketing mix for the excretion ofthe main marketing objectives. The article is based on the latestscientific literature analysis.

  20. Magnetospheric state of sawtooth events

    Science.gov (United States)

    Fung, Shing F.; Tepper, Julia A.; Cai, Xia

    2016-08-01

    Magnetospheric sawtooth events, first identified in the early 1990s, are named for their characteristic appearance of multiple quasiperiodic intervals of slow decrease followed by sharp increase of proton differential energy fluxes in the geosynchronous region. The successive proton flux oscillations have been interpreted as recurrences of stretching and dipolarization of the nightside geomagnetic field. Due to their often extended intervals with 2-10 cycles, sawteeth occurrences are sometimes referred to as a magnetospheric mode. While studies of sawtooth events over the past two decades have yielded a wealth of information about such events, the magnetospheric state conditions for the occurrence of sawtooth events and how sawtooth oscillations may depend on the magnetospheric state conditions remain unclear. In this study, we investigate the characteristic magnetospheric state conditions (specified by Psw interplanetary magnetic field (IMF) Btot, IMF Bz Vsw, AE, Kp and Dst, all time shifted with respect to one another) associated with the intervals before, during, and after sawteeth occurrences. Applying a previously developed statistical technique, we have determined the most probable magnetospheric states propitious for the development and occurrence of sawtooth events, respectively. The statistically determined sawtooth magnetospheric state has also been validated by using out-of-sample events, confirming the notion that sawtooth intervals might represent a particular global state of the magnetosphere. We propose that the "sawtooth state" of the magnetosphere may be a state of marginal stability in which a slight enhancement in the loading rate of an otherwise continuous loading process can send the magnetosphere into the marginally unstable regime, causing it to shed limited amount of energy quickly and return to the marginally stable regime with the loading process continuing. Sawtooth oscillations result as the magnetosphere switches between the marginally

  1. Centauro, Geminion and multipion events

    CERN Document Server

    Dias de Deus, J

    1980-01-01

    The authors discuss the relevance of Centauro and Geminion-like events and multihadron production as studied at cosmic-ray energies for SPS collider and ISR experiments. The experimental findings and the recent theoretical conjectures are briefly reviewed. It is suggested that in very-high-energy collisions excited quark matter hadronizes either via pionization or via baryonization without production of free quarks. Using cosmic-ray information they estimate a production cross-section for mini Centauro and Geminion events as high as 30% at SPS collider energies. (12 refs).

  2. Solar impulsive energetic electron events

    Science.gov (United States)

    Wang, Linghua

    The Sun is capable of accelerating ions from ~ tens of keV up to tens of GeV and electrons from ~ tens of eV up to hundreds of MeVs in transient events such as flares and fast coronal mass ejections (CMEs). The energized particles escaping into the interplanetary medium are referred to as Solar Energetic Particle (SEP) events. The great majority of SEP events are impulsive SEP events that are dominated by ~1-100 keV electrons and ~MeV/nucleon ion emissions, with enhanced 3 He/ 4 He ratios up to 10 4 times the coronal values (also called electron/ 3 He-rich SEP events). This thesis is focused on solar impulsive energetic electron events, the electron part of impulsive SEP events, using electron observations from the 3-D Plasma and Energetic Particle instrument (3DP) on the WIND spacecraft near the Earth. First, I present the first comprehensive statistical study of solar energetic electron events over almost one solar cycle. I find that the occurrence rate of solar electron events shows a strong solar-cycle variation; after correction for the background effect, the estimated occurrence frequency exhibits a good power-law distribution, and the estimated occurrence rate near the Earth is ~1000/year at solar maximum and ~30/year at solar minimum for the instrumental sensitivity (~2.9×10^-4 (cm 2 s str eV) -1 for the 40 keV channel) of WIND/3DP, about one order of magnitude larger than the observed occurrence rate. Solar energetic electron events have a one-to-one association with type III radio bursts and a poor association with flares, but a close association with 3 He- rich ion emissions. These 3 He-rich electron events also have a poor association with flares but a close (~ 60%) association with west-limb CMEs. Then I present two case studies: one investigating the temporal relationship between solar impulsive electrons and type III radio emissions, and the second studying the temporal relationship between solar impulsive electrons and 3 He- rich ions. For both

  3. Generic User Process Interface for Event Generators

    CERN Document Server

    Boos, E; Giele, W T; Hinchliffe, Ian; Huston, J; Ilyin, V A; Kanzaki, J; Kato, K; Kurihara, Y; Lönnblad, L; Mangano, Michelangelo L; Mrenna, S; Paige, Frank E; Richter-Was, Elzbieta; Seymour, Michael H; Sjöstrand, Torbjörn; Webber, Bryan R; Zeppenfeld, Dieter

    2001-01-01

    Generic Fortran common blocks are presented for use by High Energy Physics event generators for the transfer of event configurations from parton level generators to showering and hadronization event generators.

  4. Eventos de Mayo (May Events).

    Science.gov (United States)

    Toro, Leonor; Pla, Myrna

    Designed as a resource for teachers, this booklet, written in Spanish, contains brief information on seven May events: La Semana de la Educacion (first Friday in May), Harry S. Truman (May 8), Dia de las Madres (second Sunday in May), Luis Llorens Torres (May 14), La Cruz Roja (May 21), John F. Kennedy (May 29), and El Dia De Conmemoracion (May…

  5. Eventos de Agosto (August Events).

    Science.gov (United States)

    Toro, Leonor; Pla, Myrna

    Written in Spanish, this booklet contains brief information on seven August events celebrated by Puerto Ricans: Herbert Hoover's birthdate (August 10); Acta del Seguro Social (Social Security Act, August 14); Julian E. Blanco (August 14), Enmienda 19 Sufragia de la Mujer (Amendment 19, Women's Suffrage, August 26); Benjamin Harrison (August 20);…

  6. Event Data Definition in LHCb

    CERN Document Server

    Cattaneo, M; Frank, M; Vila, P M; Miksch, S; Roiser, S; Cattaneo, Marco; Corti, Gloria; Frank, Markus; Vila, Pere Mato; Miksch, Silvia; Roiser, Stefan

    2003-01-01

    We present the approach used for defining the event object model for the LHCb experiment. This approach is based on a high level modelling language, which is independent of the programming language used in the current implementation of the event data processing software. The different possibilities of object modelling languages are evaluated, and the advantages of a dedicated model based on XML over other possible candidates are shown. After a description of the language itself, we explain the benefits obtained by applying this approach in the description of the event model of an experiment such as LHCb. Examples of these benefits are uniform and coherent mapping of the object model to the implementation language across the experiment software development teams, easy maintenance of the event model, conformance to experiment coding rules, etc. The description of the object model is parsed by means of a so called front-end which allows to feed several back-ends. We give an introduction to the model itself and t...

  7. Host Event Based Network Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan Chugg

    2013-01-01

    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  8. Eventos de Diciembre (December Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains information on three events occurring in the month of December: winter, Christmas, and New Year's Eve. Winter is briefly discussed. The section on Christmas includes a short story ("La Nochebuena"); a poem about Christmas in Puerto Rico; a legend about the poinsettia; brief discussion of Santa…

  9. Eventos de Julio (July Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains brief information on 10 July events celebrated by Puerto Ricans: United States Declaration of Independence; the birthdays of P.T. Barnum, Elias Howe, John Quincy Adams, Luis Munoz Rivera, and Simon Bolivar; Marisol Malaret (first puerto Rican to be "Miss Universe"); Puerto Rican Constitution; Las…

  10. Eventos de Febrero (February Events).

    Science.gov (United States)

    Toro, Leonor; Pla, Myrna

    Designed as a resource for teachers, the booklet contains brief information on eight events celebrated by Puerto Ricans in the month of February: La Candelaria; Abraham Lincoln; Black History; Valentine's Day; Julia de Burgos; Luis Munoz Marin; George Washington; and the Carnaval. Written in Spanish, the booklet discusses the orgin and ways of…

  11. Eventos de Enero (January Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains brief information on the origin of four events celebrated in the month of January in Puerto Rico and the United States: New Year (January 1), Dia de Reyes (January 6), Eugenio Maria de Hostos (January 11), and Martin Luther King (January 15). Designed as a resource for teachers to use in teaching the child…

  12. Eventos de Septiembre (September Events).

    Science.gov (United States)

    Toro, Leonor, Ed.

    Written in Spanish, this booklet contains brief information on 10 September events celebrated by Puerto Ricans: Arturo Somohano, the beginning of the academic year, Dia del Trabajo (Labor Day), Pedro Albizu Campos, Lola Rodriguez de Tio, William Howard Taft, El Grito de Lares, Dia del Indio Americano (American Indian Day), las retretas, and…

  13. Eventos de Octubre (October Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains information on three events occurring in the month of October: the discovery of America (October 12), the organization of the United Nations (October 24), and Halloween (October 31). Christopher Columbus' journey to America is discussed through a short story; an epic poem ("Velas Epicas"); and…

  14. Eventos de Noviembre (November Events).

    Science.gov (United States)

    Pla, Myrna; Toro, Leonor

    Written in Spanish, this booklet contains information on three events occurring in the month of November: Armistice Day (November 11), the discovery of Puerto Rico (November 19), and Thanksgiving (last Thursday in November). Following a brief discussion of "Dia del Armisticio" (Armistice Day), first celebrated on November 11, 1919, the…

  15. Eventos de Abril (April Events).

    Science.gov (United States)

    Toro, Leonor; Pla, Myrna

    Designed for teachers, this booklet, written in Spanish, contains information on nine April events: Dia de los Tontos; Pascua de Resurreccion; Thomas Jefferson; Jose de Diego; Rosendo Matienzo Cintron; James Buchanan; Ulysses S. Grant; James Monroe; and Dia del Arbol. An overview of Dia de los Tontos is provided. Following brief descriptions of…

  16. Computational Attention for Event Detection

    OpenAIRE

    Mancas, Matei; Couvreur, Laurent; Gosselin, Bernard; Macq, Benoît

    2007-01-01

    This article deals with a biologically-motivated three-level computational attention model architecture based on the rarity and the information theory framework. It mainly focuses on low-level and medium-level steps and their application in pre-attentive detection of tumours in CT scans and unusual events in audio recordings.

  17. Eventos de Marzo (March Events).

    Science.gov (United States)

    Toro, Leonor

    Designed for teachers, this booklet, written in Spanish, contains information on seven March events: La Ley Jones; Pachin Marin; San Patricio; Primavera; Luis Pales Matos; La Masacre de Ponce; and La Esclavitud. The first section provides an overview of the Ley Jones, which introduced the bill of rights and made American citizenship obligatory for…

  18. On event based state estimation

    NARCIS (Netherlands)

    Sijs, J.; Lazar, M.

    2009-01-01

    To reduce the amount of data transfer in networked control systems and wireless sensor networks, measurements are usually taken only when an event occurs, rather than at each synchronous sampling instant. However, this complicates estimation and control problems considerably. The goal of this paper

  19. Adolescents' Evaluation of Cyberbullying Events

    Science.gov (United States)

    Gomez-Garibello, Carlos; Shariff, Shaheen; McConnell, Megan; Talwar, Victoria

    2012-01-01

    Educators and other professionals working with adolescents have grown increasingly concerned about how technology affects social relationships given the amount of time that is spent engaging in online activities. Cyberbullying has sparked the interest of many researchers due to the tragic events reported in the media, relating to the online…

  20. Uniqueness of Centauro-type events

    Energy Technology Data Exchange (ETDEWEB)

    Augusto, C.R.A.; Barroso, S.L.C.; Beggio, P.C.; Carvalho, A.O. de; Menon, M.J.; Navia, C.E.; Oliveira, R. de; Shibuya, E.H

    2003-07-01

    Analysis to discriminate Centauro events from normal events is made without previous identification of secondary emitted particles. For this purpose their energy and derived quantities like distance from the center of momenta it were mainly used. As a result we found in a sample of (280+87) experimental events only 3 were compatible with 5 Centauro events, but none of them dad a high content of hadrons, characteristic of Centauro events. With this result we are confident about the uniqueness of Centauro events, especially for two events that have vertex directly determined. Comparing with some interaction models features we depict a possible scenario to explain Centauro events.

  1. Pregnancy as a psychological event

    Directory of Open Access Journals (Sweden)

    Bjelica Artur L.

    2004-01-01

    Full Text Available Introduction Apart from physiological and somatic changes, pregnancy is a complex phenomenon which also includes psychological and social changes. Pregnancy, especially the first one, represents a powerful psychological event. This paper deals with pregnancy as a psychological event, considering psychological changes in the course of pregnancy as a stressful event. Psychological changes during pregnancy Pregnancy is always associated with changes in psychological functioning of pregnant women. It is usually associated with ambivalence, frequent mood changes, varying from anxiety, fatigue, exhaustion, sleepiness, depressive reactions to excitement. During pregnancy, changes include body appearance, affectivity and sexuality, whereas the position and role of women attains a new quality. Even thoughts of pregnancy can bring about numerous worries about its course and outcome, and especially of the delivery itself, which may be so intense that they acquire a features of phobia (which may be the reason for avoiding pregnancy. Pregnancy as a stressful event Pregnancy is identified as a potent stressor that can seriously affect the psychic status of pregnant women, perinatal outcome, but also psychic functioning of the new-born individual. Appropriate relationship of partners and support of the society play an important role in overcoming stress during pregnancy. Conclusion Pregnancy is an event that involves numerous somatic and psychological changes. However, pregnancy can also be a potent stressor. Existence of prenatal maternal stress may lead to different perinatal complications that may have long-term consequences on the newborn. In prevention of maternal stress emphasis has to be put on partner’s emotional support, as well as empathy of the social environment. However, in certain cases, professional psychotherapeutic support is necessary, in form of short supportive treatment. Preventive measures should include adequate psychological support

  2. EDICAM (Event Detection Intelligent Camera)

    Energy Technology Data Exchange (ETDEWEB)

    Zoletnik, S. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Szabolics, T., E-mail: szabolics.tamas@wigner.mta.hu [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Kocsis, G.; Szepesi, T.; Dunai, D. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary)

    2013-10-15

    Highlights: ► We present EDICAM's hardware modules. ► We present EDICAM's main design concepts. ► This paper will describe EDICAM firmware architecture. ► Operation principles description. ► Further developments. -- Abstract: A new type of fast framing camera has been developed for fusion applications by the Wigner Research Centre for Physics during the last few years. A new concept was designed for intelligent event driven imaging which is capable of focusing image readout to Regions of Interests (ROIs) where and when predefined events occur. At present these events mean intensity changes and external triggers but in the future more sophisticated methods might also be defined. The camera provides 444 Hz frame rate at full resolution of 1280 × 1024 pixels, but monitoring of smaller ROIs can be done in the 1–116 kHz range even during exposure of the full image. Keeping space limitations and the harsh environment in mind the camera is divided into a small Sensor Module and a processing card interconnected by a fast 10 Gbit optical link. This camera hardware has been used for passive monitoring of the plasma in different devices for example at ASDEX Upgrade and COMPASS with the first version of its firmware. The new firmware and software package is now available and ready for testing the new event processing features. This paper will present the operation principle and features of the Event Detection Intelligent Camera (EDICAM). The device is intended to be the central element in the 10-camera monitoring system of the Wendelstein 7-X stellarator.

  3. Bulk Viscosity Effects in Event-by-Event Relativistic Hydrodynamics

    CERN Document Server

    Noronha-Hostler, Jacquelyn; Noronha, Jorge; Andrade, Rone P G; Grassi, Frederique

    2013-01-01

    Bulk viscosity effects on the collective flow harmonics in heavy ion collisions are investigated, on an event by event basis, using a newly developed 2+1 Lagrangian hydrodynamic code named v-USPhydro which implements the Smoothed Particle Hydrodynamics (SPH) algorithm for viscous hydrodynamics. A new formula for the bulk viscous corrections present in the distribution function at freeze-out is derived starting from the Boltzmann equation for multi-hadron species. Bulk viscosity is shown to enhance the collective flow Fourier coefficients from $v_2(p_T)$ to $v_5(p_T)$ when $% p_{T}\\sim 1-3$ GeV even when the bulk viscosity to entropy density ratio, $% \\zeta/s$, is significantly smaller than $1/(4\\pi)$.

  4. Applications of Event-by-Event Fission Modeling with FREYA

    Directory of Open Access Journals (Sweden)

    Vogt R.

    2012-02-01

    Full Text Available The recently developed code FREYA (Fission Reaction Event Yield Algorithm generates large samples of complete fission events, consisting of two receding product nuclei as well as a number of neutrons and photons, all with complete kinematic information. Thus it is possible to calculate arbitrary correlation observables whose behavior may provide unique insight into the fission process. We first discuss the present status of FREYA, which has now been extended to include spontaneous fission. Concentrating on 239Pu(nth,f, 240Pu(sf and 252Cf(sf, we discuss the neutron multiplicity correlations, the dependence of the neutron energy spectrum on the neutron multiplicity, and the relationship between the fragment kinetic energy and the number of neutrons and their energies. We also suggest novel fission observables that could be measured with modern detectors.

  5. Calculation of Fission Observables Through Event-by-Event Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Randrup, J; Vogt, R

    2009-06-04

    The increased interest in more exclusive fission observables has demanded more detailed models. We present here a new computational model, FREYA, that aims to met this need by producing large samples of complete fission events from which any observable of interest can then be extracted consistently, including arbitrary correlations. The various model assumptions are described and the potential utility of the model is illustrated by means of several novel correlation observables.

  6. On causality of extreme events

    CERN Document Server

    Zanin, Massimiliano

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect both linear and non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task.

  7. The probabilities of unique events.

    Directory of Open Access Journals (Sweden)

    Sangeet S Khemlani

    Full Text Available Many theorists argue that the probabilities of unique events, even real possibilities such as President Obama's re-election, are meaningless. As a consequence, psychologists have seldom investigated them. We propose a new theory (implemented in a computer program in which such estimates depend on an intuitive non-numerical system capable only of simple procedures, and a deliberative system that maps intuitions into numbers. The theory predicts that estimates of the probabilities of conjunctions should often tend to split the difference between the probabilities of the two conjuncts. We report two experiments showing that individuals commit such violations of the probability calculus, and corroborating other predictions of the theory, e.g., individuals err in the same way even when they make non-numerical verbal estimates, such as that an event is highly improbable.

  8. Optimizing Event-Driven Simulations

    CERN Document Server

    De Michele, Cristiano

    2010-01-01

    Event-driven molecular dynamics is a valuable tool in condensed and soft matter physics when particles can be modeled as hard objects or more generally if their interaction potential can be modeled in a stepwise fashion. Hard spheres model has been indeed widely used both for computational and theoretical description of physical systems. Recently further developments of computational techniques allow simulations of hard rigid objects of generic shape. In present paper we will present some optimizations for event-driven simulations that offered significant speedup over previous methods. In particular we will describe a generalization of well known linked list method and an improvement on nearest neighbor lists method recently proposed by us.

  9. Parasitic Events in Envelope Analysis

    Directory of Open Access Journals (Sweden)

    J. Doubek

    2001-01-01

    Full Text Available Envelope analysis allows fast fault location of individual gearboxes and parts of bearings by repetition frequency determination of the mechanical catch of an amplitude-modulated signal. Systematic faults arise when using envelope analysis on a signal with strong changes. The source of these events is the range of function definition of used in convolution integral definition. This integral is used for Hilbert image calculation of analyzed signal. Overshoots (almost similar to Gibbs events on a synthetic signal using the Fourier series are result from these faults. Overshoots are caused by parasitic spectral lines in the frequency domain, which can produce faulty diagnostic analysis.This paper describes systematic arising during faults rising by signal numerical calculation using envelope analysis with Hilbert transform. It goes on to offer a mathematical analysis of these systematic faults.

  10. On causality of extreme events

    Directory of Open Access Journals (Sweden)

    Massimiliano Zanin

    2016-06-01

    Full Text Available Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available.

  11. On causality of extreme events

    Science.gov (United States)

    2016-01-01

    Multiple metrics have been developed to detect causality relations between data describing the elements constituting complex systems, all of them considering their evolution through time. Here we propose a metric able to detect causality within static data sets, by analysing how extreme events in one element correspond to the appearance of extreme events in a second one. The metric is able to detect non-linear causalities; to analyse both cross-sectional and longitudinal data sets; and to discriminate between real causalities and correlations caused by confounding factors. We validate the metric through synthetic data, dynamical and chaotic systems, and data representing the human brain activity in a cognitive task. We further show how the proposed metric is able to outperform classical causality metrics, provided non-linear relationships are present and large enough data sets are available. PMID:27330866

  12. Answering Questions about Complex Events

    Science.gov (United States)

    2008-12-19

    Thirdly, it should be cognitively motivated to allow humans to easily add content, query, and make sense of the information returned. Finally, event...Understanding in Embodied Construction Grammar. Construction Grammar(s): Cognitive and Cross- language dimensions, John Benjamins. Bethard, S. J. (2007... Lexicography 16(3). Fillmore, C. J. (1982). Frame Semantics. Linguistics in the Morning Calm. Seoul, Hanshin: 111-38. Fliedner, G. (2004). Towards Using

  13. The dynamic chain event graph

    OpenAIRE

    2015-01-01

    In this paper we develop a formal dynamic version of Chain Event Graphs (CEGs), a particularly expressive family of discrete graphical models. We demonstrate how this class links to semi-Markov models and provides a convenient generalization of the Dynamic Bayesian Network (DBN). In particular we develop a repeating time-slice Dynamic CEG providing a useful and simpler model in this family. We demonstrate how the Dynamic CEG’s graphical formulation exhibits asymmetric conditional independence...

  14. Metrics for Event Driven Software

    Directory of Open Access Journals (Sweden)

    Neha Chaudhary

    2016-01-01

    Full Text Available The evaluation of Graphical User Interface has significant role to improve its quality. Very few metrics exists for the evaluation of Graphical User Interface. The purpose of metrics is to obtain better measurements in terms of risk management, reliability forecast, project scheduling, and cost repression. In this paper structural complexity metrics is proposed for the evaluation of Graphical User Interface. Structural complexity of Graphical User Interface is considered as an indicator of complexity. The goal of identifying structural complexity is to measure the GUI testability. In this testability evaluation the process of measuring the complexity of the user interface from testing perspective is proposed. For the GUI evaluation and calculating structural complexity an assessment process is designed which is based on types of events. A fuzzy model is developed to evaluate the structural complexity of GUI. This model takes five types of events as input and return structural complexity of GUI as output. Further a relationship is established between structural complexity and testability of event driven software. Proposed model is evaluated with four different applications. It is evident from the results that higher the complexities lower the testability of application.

  15. Valanginian Weissert oceanic anoxic event

    Science.gov (United States)

    Erba, Elisabetta; Bartolini, Annachiara; Larson, Roger L.

    2004-02-01

    Biotic changes in nannofossils and radiolarians associated with the Valanginian δ13C anomaly are documented at Ocean Drilling Program Hole 1149B in the Pacific Ocean: they are coeval and similar to those previously documented in the Tethys, suggesting a global perturbation of marine ecosystems. A marked increase in abundance of Diazomatolithus, absence of nannoconids, and a Pantanellium peak characterize the Valanginian δ13C excursion. Such changes are interpreted as being due to global enhanced fertility and a biocalcification crisis under conditions of excess CO2. The occurrence of organic C rich black shales in the Southern Alps and in the Pacific in the interval corresponding to the δ13C excursion suggests a Valanginian oceanic anoxic event (OAE). Volcanism of the Paranà-Etendeka large igneous province (ca. 132 Ma) was presumably responsible for an increase of CO2, triggering a climate change and accelerated hydrological cycling, possibly causing an indirect fertilization of the oceans. Widespread nutrification via introduction of biolimiting metals at spreading ridges could have significantly increased during the Gondwana breakup and simultaneous tectonic events in three separate oceans. There is no paleontological or δ18O evidence of warming during the Valanginian OAE. On the contrary, both nannofossils and oxygen isotopes record a cooling event at the climax of the δ13C excursion. Weathering of basalts and burial of organic C rich black shales were presumably responsible for CO2 drawdown and establishment of reversed greenhouse conditions.

  16. 36 CFR 327.21 - Special events.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Special events. 327.21... § 327.21 Special events. (a) Special events including, but not limited to, water carnivals, boat... sponsor of such event unless the District Commander has approved in writing (and the sponsor has...

  17. 36 CFR 1002.50 - Special events.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Special events. 1002.50... RECREATION § 1002.50 Special events. (a) Sports events, pageants, regattas, public spectator attractions, entertainments, ceremonies, and similar events are allowed: Provided, however, There is a meaningful...

  18. 36 CFR 2.50 - Special events.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Special events. 2.50 Section... PROTECTION, PUBLIC USE AND RECREATION § 2.50 Special events. (a) Sports events, pageants, regattas, public spectator attractions, entertainments, ceremonies, and similar events are allowed: Provided, however,...

  19. 36 CFR 331.11 - Special events.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Special events. 331.11..., KENTUCKY AND INDIANA § 331.11 Special events. (a) Special events including, but not limited to, water... charged any fee by the sponsor of such permitted event unless the District Engineer has approved...

  20. Research on Event Handling Models of Java

    Institute of Scientific and Technical Information of China (English)

    WU Yue; WU Jing; ZHOU Ming-tian

    2004-01-01

    A new event-handling paradigm and its application model are proposed. The working mechanism and principle of event listener model is given in detail. Finally, the launching event mechanisms,the choosing event handling models and the dispatching mechanism are illustrated.

  1. Attracting New Audiences through Special Events.

    Science.gov (United States)

    Christyson, M. Jane

    1996-01-01

    Explores reasons to create special events, change existing events, or discontinue events, in the pursuit of new audiences. Describes surveys of usership at Cleveland Metroparks to identify new audiences. Effective event design and implementation requires effective advertising, which is expensive, so a discussion of fund development, branding, and…

  2. Rare events: a state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Uppuluri, V.R.R.

    1980-12-01

    The study of rare events has become increasingly important in the context of nuclear safety. Some philosophical considerations, such as the framework for the definition of a rare event, rare events and science, rare events and trans-science, and rare events and public perception, are discussed. The technical work of the Task Force on problems of Rare Events in the Reliability Analysis of Nuclear Plants (1976-1978), sponsored by OECD, is reviewed. Some recent technical considerations are discussed, and conclusions are drawn. The appendix contains an essay written by Anne E. Beachey, under the title: A Study of Rare Events - Problems and Promises.

  3. The ATLAS Event Service: A new approach to event processing

    Science.gov (United States)

    Calafiura, P.; De, K.; Guan, W.; Maeno, T.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Tsulaia, V.; Van Gemmeren, P.; Wenaus, T.

    2015-12-01

    The ATLAS Event Service (ES) implements a new fine grained approach to HEP event processing, designed to be agile and efficient in exploiting transient, short-lived resources such as HPC hole-filling, spot market commercial clouds, and volunteer computing. Input and output control and data flows, bookkeeping, monitoring, and data storage are all managed at the event level in an implementation capable of supporting ATLAS-scale distributed processing throughputs (about 4M CPU-hours/day). Input data flows utilize remote data repositories with no data locality or pre-staging requirements, minimizing the use of costly storage in favor of strongly leveraging powerful networks. Object stores provide a highly scalable means of remotely storing the quasi-continuous, fine grained outputs that give ES based applications a very light data footprint on a processing resource, and ensure negligible losses should the resource suddenly vanish. We will describe the motivations for the ES system, its unique features and capabilities, its architecture and the highly scalable tools and technologies employed in its implementation, and its applications in ATLAS processing on HPCs, commercial cloud resources, volunteer computing, and grid resources. Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  4. Accounting the Events after the Balance Date

    OpenAIRE

    Ilincuţă Lucian-Dorel; Mareş Marius-Daniel; Mareş Valerica

    2014-01-01

    The events after the balance date are those events, favorable and unfavorable, that occur between the balance date (the end of the reporting period) and the date at which the annual financial statements are authorized for issue by the executive management of the entity (e.g. Board of Directors). We identify two types of events: events after the balance date, which lead to financial statements adjusting and events after the balance date, which do not lead to financ...

  5. 78 FR 53383 - National Cemeteries, Demonstration, Special Event

    Science.gov (United States)

    2013-08-29

    ... event, pageant, celebration, historical reenactment, entertainment, exhibition, parade, fair, festival.... * * * * * Special event means a sports event, pageant, celebration, historical reenactment,...

  6. Colour reconnection in WW events

    CERN Document Server

    D'Hondt, J

    2003-01-01

    Preliminary results are presented for a measurement of the kappa parameter used in the JETSET SK-I model of colour reconnection in W /sup +/W/sup -/ to qq'qq' events at LEP2. An update on the investigation of colour reconnection effects in hadronic decays of W pairs, using the particle flow in DELPHI is presented. A second method is based on the observation that two different m/sub W/ estimators have different sensitivity to the parametrised colour reconnection effect. Hence the difference between them is an observable with information content about kappa. (6 refs).

  7. Hadron rich and Centauro events

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, S.L.C. [Centro Brasileiro de Pesquisas Fisicas, 22290-180 Rio de Janeiro, RJ (Brazil); Beggio, P.C. [Laboratorio de Ciencias Matematicas, UENF, Campos de Goytacazes, RJ (Brazil); Carvalho, A.O. de; Chinellato, J.A.; Mariano, A.; Oliveira, R. de; Shibuya, E.H. [Instituto de Fisica ' Gleb Wataghin' /UNICAMP, 13083-970 Campinas, SP (Brazil)

    2008-01-15

    An exploratory statistical analysis of the event C16S086I037 was possible to do using two simulations. A {gamma} and hadron induced showers recognition done on this event through a best fitting procedure shows identification of 25 and 37 for {gamma} and hadron induced showers, respectively. Assuming that the most energetic shower is the surviving particle of an interaction and the tertiary produced particles are from normal multiple pion production, the characteristics of the interaction are: Energy of primary particle E{sub 0}=1,061 TeV, Inelasticity of collision K=0.81, Mean inelasticity of {gamma}-ray =0.27, Hadron induced showers energy/Total energy Q{sub h}{sup '}=0.90{approx}Q{sub h}, Rapidity density N{sub h}/{delta}Y=(8.56-9.89), Mean energy of secondary hadrons =(21.5{+-}4) TeV, Mean transverse momentum =(1.2{+-}0.2) GeV/c, Upper bound of partial cross section {sigma}{<=}(15-39){mu}barn and life time {tau}{<=}10{sup -16} s. Without the surviving particle assumption, the values are: E{sub 0}=873 TeV, K=1.0, =1/3, Q{sub h}{sup '}=0.90, N{sub h}/{delta}Y=(8.32-9.34), =(21{+-}3.5) TeV, =(1.0{+-}0.16) GeV/c. Using another simulation for energy determination with {chi}{sup 2}>3.16 for best fitting results 22 and 40 for {gamma} and hadron induced showers, respectively. Under the surviving particle assumption, the figures are: Energy of primary particle E{sub 0}=1,047 TeV, Inelasticity of collision K=0.80, Mean inelasticity of {gamma}-ray =0.27, Hadronic induced showers energy/Total energy Q{sub h}{sup '}=0.89{approx}Q{sub h}, Rapidity density N{sub h}/{delta}Y=(10.25-13.19), Mean energy of secondary hadrons =(19{+-}3) TeV, Mean transverse momentum =(1.0{+-}0.2) GeV/c. That is, we get almost similar figures independently of simulation and a mean transverse momentum for this hadron-rich event similar to the Centauro events.

  8. Programming Idioms for Transactional Events

    Directory of Open Access Journals (Sweden)

    Matthew Kehrt

    2010-02-01

    Full Text Available Transactional events (TE are an extension of Concurrent ML (CML, a programming model for synchronous message-passing. Prior work has focused on TE's formal semantics and its implementation. This paper considers programming idioms, particularly those that vary unexpectedly from the corresponding CML idioms. First, we solve a subtle problem with client-server protocols in TE. Second, we argue that CML's wrap and guard primitives do not translate well to TE, and we suggest useful workarounds. Finally, we discuss how to rewrite CML protocols that use abort actions.

  9. The LCLS Timing Event System

    Energy Technology Data Exchange (ETDEWEB)

    Dusatko, John; Allison, S.; Browne, M.; Krejcik, P.; /SLAC

    2012-07-23

    The Linac Coherent Light Source requires precision timing trigger signals for various accelerator diagnostics and controls at SLAC-NAL. A new timing system has been developed that meets these requirements. This system is based on COTS hardware with a mixture of custom-designed units. An added challenge has been the requirement that the LCLS Timing System must co-exist and 'know' about the existing SLC Timing System. This paper describes the architecture, construction and performance of the LCLS timing event system.

  10. PC 2 Phone Event Announcer

    CERN Document Server

    Parhizkar, Behrang; Ali, Mohammad Nabil Sadegh; Ramachandran, Anand; Navaratnam, Sujata

    2010-01-01

    Nowadays, mobile phones are indispensable devices; it has become a trend now that college and university students are owners of such devices and this particular factor plays a very important role behind the coming up with the proposed system. "PC 2 Phone event Announcer", is the name of the new proposed system suggested to solve the existing communication problem between the College staff and students. As the name suggests, it can be deduced that the system will involve computers and phones, more specifically mobile phones.

  11. Video fingerprinting for live events

    Science.gov (United States)

    Celik, Mehmet; Haitsma, Jaap; Barvinko, Pavlo; Langelaar, Gerhard; Maas, Martijn

    2009-02-01

    Multimedia fingerprinting (robust hashing) as a content identification technology is emerging as an effective tool for preventing unauthorized distribution of commercial content through user generated content (UGC) sites. Research in the field has mainly considered content types with slow distribution cycles, e.g. feature films, for which reference fingerprint ingestion and database indexing can be performed offline. As a result, research focus has been on improving the robustness and search speed. Live events, such as live sports broadcasts, impose new challenges on a fingerprinting system. For instance, highlights from a soccer match are often available-and viewed-on UGC sites well before the end of the match. In this scenario, the fingerprinting system should be able to ingest and index live content online and offer continuous search capability, where new material is identifiable within minutes of broadcast. In this paper, we concentrate on algorithmic and architectural challenges we faced when developing a video fingerprinting solution for live events. In particular, we discuss how to effectively utilize fast sorting algorithms and a master-slave architecture for fast and continuous ingestion of live broadcasts.

  12. Measurable events indexed by trees

    CERN Document Server

    Dodos, Pandelis; Tyros, Konstantinos

    2011-01-01

    A tree $T$ is said to be homogeneous if it is uniquely rooted and there exists an integer $b\\geq 2$, called the branching number of $T$, such that every $t\\in T$ has exactly $b$ immediate successors. We study the behavior of measurable events in probability spaces indexed by homogeneous trees. Precisely, we show that for every integer $b\\geq 2$ and every integer $n\\geq 1$ there exists an integer $q(b,n)$ with the following property. If $T$ is a homogeneous tree with branching number $b$ and $\\{A_t:t\\in T\\}$ is a family of measurable events in a probability space $(\\Omega,\\Sigma,\\mu)$ satisfying $\\mu(A_t)\\geq\\epsilon>0$ for every $t\\in T$, then for every $0<\\theta<\\epsilon$ there exists a strong subtree $S$ of $T$ of infinite height such that for every non-empty finite subset $F$ of $S$ of cardinality $n$ we have \\[ \\mu\\Big(\\bigcap_{t\\in F} A_t\\Big) \\meg \\theta^{q(b,n)}. \\] In fact, we can take $q(b,n)= \\big((2^b-1)^{2n-1}-1\\big)\\cdot(2^b-2)^{-1}$. A finite version of this result is also obtained.

  13. First ATLAS Events Recorded Underground

    CERN Multimedia

    Teuscher, R

    As reported in the CERN Bulletin, Issue No.30-31, 25 July 2005 The ATLAS barrel Tile calorimeter has recorded its first events underground using a cosmic ray trigger, as part of the detector commissioning programme. This is not a simulation! A cosmic ray muon recorded by the barrel Tile calorimeter of ATLAS on 21 June 2005 at 18:30. The calorimeter has three layers and a pointing geometry. The light trapezoids represent the energy deposited in the tiles of the calorimeter depicted as a thick disk. On the evening of June 21, the ATLAS detector, now being installed in the underground experimental hall UX15, reached an important psychological milestone: the barrel Tile calorimeter recorded the first cosmic ray events in the underground cavern. An estimated million cosmic muons enter the ATLAS cavern every 3 minutes, and the ATLAS team decided to make good use of some of them for the commissioning of the detector. Although only 8 of the 128 calorimeter slices ('superdrawers') were included in the trigg...

  14. Rare Events and Conditional Events on Random Strings

    Directory of Open Access Journals (Sweden)

    Mireille Régnier

    2004-12-01

    Full Text Available Some strings -the texts- are assumed to be randomly generated, according to a probability model that is either a Bernoulli model or a Markov model. A rare event is the over or under-representation of a word or a set of words. The aim of this paper is twofold. First, a single word is given. One studies the tail distribution of the number of its occurrences. Sharp large deviation estimates are derived. Second, one assumes that a given word is overrepresented. The distribution of a second word is studied; formulae for the expectation and the variance are derived. In both cases, the formulae are accurate and actually computable. These results have applications in computational biology, where a genome is viewed as a text.

  15. Event planning the ultimate guide to successful meetings, corporate events, fundraising galas, conferences, conventions, incentives and other special events

    CERN Document Server

    Allen, Judy

    2009-01-01

    This bestselling all–in–one guide to the event planning business is back and better than ever, fully updated and revised to reflect the very latest trends and best practices in the industry. This handy, comprehensive guide includes forms, checklists, and tips for managing events, as well as examples and case studies of both successful and unsuccessful events. Judy Allen (Toronto, ON, Canada) is founder and President of Judy Allen Productions, a full–service event planning production company.

  16. Extreme events monitoring from space

    Science.gov (United States)

    Kerr, Yann; Bitar, Ahmad Al; Mahmoodi, Ali; Richaume, Philippe; Al-Yaari, Amen; Wigneron, Jean-Pierre

    2016-04-01

    The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to provide soil moisture over continental surface (with an accuracy goal of 0.04 m3/m3), vegetation water content over land, and ocean salinity. These geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge at a global scale is of interest for climatic and weather researches, and in particular in improving model forecasts. The Soil Moisture and Ocean Salinity mission has now been collecting data for 6 years. The whole data set has just been reprocessed (Version 620 for levels 1 and 2 and version 3 for level 3 CATDS). After 6 years it seems important to start using data for having a look at anomalies and see how they can relate to large scale events The purpose of this communication is to present the mission results after more than six years in orbit in a climatic trend perspective, as through such a period anomalies can be detected. Thereby we benefit from consistent datasets provided through the latest reprocessing using most recent algorithm enhancements. Using the above mentioned products it is possible to follow large events such as the evolution of the droughts in North America, or water fraction evolution over the Amazonian basin. In this occasion we will focus on the analysis of SMOS and ancillary products anomalies to reveal two climatic trends, the temporal evolution of water storage over the Indian continent in relation to rainfall anomalies, and the global impact of El Nino types of events on the general water storage distribution. This presentation shows in detail the use of long term data sets of L-band microwave radiometry in two specific cases, namely droughts and water budget over a large basin. Several other analyses are under way currently. Obviously, vegetation water content, but also dielectric constant, are carrying a wealth

  17. CDC Wonder Vaccine Adverse Event Reporting System

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Vaccine Adverse Event Reporting System (VAERS) online database on CDC WONDER provides counts and percentages of adverse event case reports after vaccination,...

  18. Energy spectra in relativistic electron precipitation events.

    Science.gov (United States)

    Rosenberg, T. J.; Lanzerotti, L. J.; Bailey, D. K.; Pierson, J. D.

    1972-01-01

    Two events in August 1967, categorized as relativistic electron precipitation (REP) events by their effect on VHF transmissions propagated via the forward-scatter mode, have been examined with regard to the energy spectra of trapped and precipitated electrons. These two substorm-associated events August 11 and August 25 differ with respect to the relativistic, trapped electron population at synchronous altitude; in the August 25 event there was a nonadiabatic enhancement of relativistic (greater than 400 keV) electrons, while in the August 11 event no relativistic electrons were produced. In both events electron spectra deduced from bremsstrahlung measurements (made on a field line close to that of the satellite) had approximately the same e-folding energies as the trapped electron enhancements. However, the spectrum of electrons in the August 25 event was significantly harder than the spectrum in the event of August 11.

  19. Electron optics of microlenses with inclined beams

    NARCIS (Netherlands)

    Zhang, Y.; Barth, J.E.; Kruit, P.

    2008-01-01

    For multielectron beam systems with a single electron source, the outside beams need to be collimated before entering the individual microcolumns. As an alternative of the traditional multibeam source design where the broad beam from the source is collimated by a single lens, the broad beam can be f

  20. Uncovering stellar atmospheres with gravitational microlensing telescopes

    CERN Document Server

    Dominik, M

    2003-01-01

    A strong differential magnification over the face of the source star passing the caustic created by a binary lens star allows to measure its radial intensity profile with an angular resolution of 20-60 nas from broad-band photometric observations for ~15 stars per year and to study its chemical composition from time-resolved high-resolution spectroscopy for ~2 stars per year.