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Results for "I. Soszyński"

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Search for binary central stars of the SMC PNeDec 20 2013The Optical Gravitational Lensing Experiment (OGLE), originally designed to search for microlensing events, provides a rich and uniform data set suitable for studying the variability of certain types of objects. We used the OGLE data to study the photometry ... More
On the long cycle variability of the Algol OGLE-LMC-DPV-065 and its stellar, orbital and disk parametersMay 10 2019OGLE-LMC-DPV-065 is an interacting binary whose double-hump long photometric cycle remains hitherto unexplained. We analyze photometric time series available in archive datasets spanning 124 years and present the analysis of new high-resolution spectra. ... More
Accurate stellar parameters and distance to two evolved eclipsing binary systems, OGLE-BLG-ECL-123903 and OGLE-BLG-ECL-296596, towards the Galactic bulgeApr 09 2019Aim: Our aim is to obtain high-accuracy measurements of the physical and orbital parameters of two evolved eclipsing binary systems, and to use these measurements to study their evolutionary status. We also aim to derive distances to the systems by using ... More
Type II Cepheids Pulsating in the First Overtone from the OGLE SurveyFeb 06 2019We report the discovery of the first type II Cepheids (BL Herculis stars) pulsating solely in the first overtone. We found two such objects among tens of millions of stars regularly observed by the OGLE survey in the Large Magellanic Cloud. Our classification ... More
OGLE-ing the Magellanic System: Cepheids in the BridgeApr 17 2019We present a detailed analysis of Magellanic Bridge Cepheid sample constructed using the OGLE Collection of Variable Stars. Our updated Bridge sample contains 10 classical and 13 anomalous Cepheids. We calculate their individual distances using optical ... More
A Venus-Mass Planet Orbiting a Brown Dwarf: Missing Link between Planets and MoonsJul 09 2015Jul 13 2015The co-planarity of solar-system planets led Kant to suggest that they formed from an accretion disk, and the discovery of hundreds of such disks around young stars as well as hundreds of co-planar planetary systems by the Kepler satellite demonstrate ... More
The Araucaria Project. Binary Classical Cepheids in the LMCJul 07 2014The status of our work on binary classical cepheid systems in the Large Magellanic Cloud is presented. We report on results from our follow up of two eclipsing binary cepheids OGLE-LMC-CEP-0227 and OGLE-LMC-CEP-1812. Here we presented for the first time ... More
Photometry of two unusual A supergiant systems in the Small Magellanic CloudApr 15 2010We present multiwavelength broadband photometry and V, I time resolved photometry for two variable bright stars in the SMC, OGLE004336.91-732637.7 (SMC-SC3) and OGLE004633.76-731204.3 (SMC-SC4). The light curves span 12 years and show long-term periodicities ... More
Long Secondary Periods in Variable Red GiantsJul 17 2009We present a study of a sample of LMC red giants exhibiting Long Secondary Periods (LSPs). We use radial velocities obtained from VLT spectral observations and MACHO and OGLE light curves to examine properties of the stars and to evaluate models for the ... More
The SMC B-type supergiant AzV322: a g-mode pulsator with a circumstellar discOct 06 2017We present a photometric and spectroscopic study of AzV322, an emission line object located in the Small Magellanic Cloud previously classified between O9 and B0. We analyze 17.5 years of $I$ and $V$ band OGLE-II, III and IV light curves and find four ... More
A Wide Orbit Exoplanet OGLE-2012-BLG-0838LbJan 16 2019We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star projected separation is found to be twice larger than ... More
A Super-Jupiter Microlens Planet Characterized by High-Cadence KMTNet Microlensing Survey Observations of OGLE-2015-BLG-0954Feb 29 2016Jun 23 2016We report the characterization of a massive (m_p=3.9 +- 1.4 M_jup) microlensing planet (OGLE-2015-BLG-0954Lb) orbiting an M dwarf host (M=0.33 +- 0.12 M_sun) at a distance toward the Galactic bulge of 0.6 (+0.4,-0.2) kpc, which is extremely nearby by ... More
The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. XII. Eclipsing Binary Stars in the Large Magellanic CloudAug 01 2011We present catalog of 26 121 visually inspected eclipsing binary stars identified in the Large Magellanic Cloud during the third phase of the Optical Gravitational Lensing Experiment. The sample is limited to the out-of-eclipse brightness I < 20 mag. ... More
The Optical Gravitational Lensing Experiment. OGLE-III Photometric Maps of the Galactic Bulge FieldsJul 20 2011We present OGLE-III Photometric Maps of the Galactic bulge fields observed during the third phase of the OGLE project. This paper describes the last, concluding set of maps based on OGLE-III data. The maps contain precise, calibrated VI photometry of ... More
The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. X. Enigmatic Class of Double Periodic Variables in the Large Magellanic CloudSep 27 2010Oct 26 2010The tenth part of the OGLE-III Catalog of Variable Stars contains 125 Double Periodic Variables (DPVs) from the Large Magellanic Cloud. DPVs are semi-detached binaries which show additional variability with a period around 33 times longer than the orbital ... More
The Tarantula Massive Binary Monitoring: I. Observational campaign and OB-type spectroscopic binariesOct 11 2016Mar 13 2017Massive binaries (MBs) play a crucial role in the Universe. Knowing the distributions of their orbital parameters (OPs) is important for a wide range of topics, from stellar feedback to binary evolution channels, from the distribution of supernova types ... More
The Optical Gravitational Lensing Experiment. OGLE-III Photometric Maps of the Galactic Disk FieldsJan 10 2011We present OGLE-III Photometric Maps of the Galactic disk fields observed during the OGLE-III campaigns for low luminosity transiting objects that led to the discovery of the first transiting exoplanets. The maps contain precise, calibrated VI photometry ... More
The Optical Gravitational Lensing Experiment. The Catalog of Stellar Proper Motions toward the Magellanic CloudsMar 12 2012Apr 25 2012We present a catalog of over 6.2 million stars with measured proper motions. All these stars are observed in the direction of the Magellanic Clouds within the brightness range 12 < I < 19 mag. Based on these proper motions about 440 000 Galactic foreground ... More
The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. VI. Delta Scuti Stars in the Large Magellanic CloudApr 06 2010The sixth part of the OGLE-III catalog of Variable Stars presents \delta Sct pulsators in the Large Magellanic Cloud. Altogether 2786 variable stars were found and amongst them 92 are multi-mode objects, including 67 stars pulsating in the fundamental ... More
The Araucaria Project: The First-Overtone Classical Cepheid in the Eclipsing System OGLE-LMC-CEP-2532Apr 17 2015We present here the first spectroscopic and photometric analysis of the double-lined eclipsing binary containing the classical, first-overtone Cepheid OGLE-LMC-CEP-2532 (MACHO 81.8997.87). The system has an orbital period of 800 days and the Cepheid is ... More
OGLE-2016-BLG-0613LABb: A Microlensing Planet in a Binary SystemOct 02 2017We present the analysis of OGLE-2016-BLG-0613, for which the lensing light curve appears to be that of a typical binary-lens event with two caustic spikes but with a discontinuous feature on the trough between the spikes. We find that the discontinuous ... More
The VLT-FLAMES Tarantula Survey V. The peculiar B[e]-like supergiant, VFTS698, in 30 DoradusJan 30 2012Apr 20 2012We present an analysis of a peculiar supergiant B-type star (VFTS698/Melnick 2/Parker 1797) in the 30 Doradus region of the Large Magellanic Cloud which exhibits characteristics similar to the broad class of B[e] stars. We analyse optical spectra from ... More
The Optical Gravitational Lensing Experiment. Dwarf Novae in the OGLE Data. I. Three New Dwarf Novae: One in the Period Gap and Two Longer Period ObjectsJul 12 2011We report serendipitous discovery of three new dwarf novae which eruptions in 2010 were observed by the ongoing microlensing survey OGLE-IV. All three objects are located in the Galactic bulge fields observed with the highest cadence of 20 minutes. In ... More
OGLE-2014-BLG-0257L: A Microlensing Brown Dwarf Orbiting a Low-mass M DwarfMar 15 2016In this paper, we report the discovery of a binary composed of a brown dwarf and a low-mass M dwarf from the observation of the microlensing event OGLE-2014-BLG-0257. Resolution of the very short-lasting caustic crossing combined with the detection of ... More
The panchromatic view of the Magellanic Clouds from Classical Cepheids. I. Distance, Reddening and Geometry of the Large Magellanic Cloud diskSep 12 2016Sep 13 2016We present a detailed investigation of the Large Magellanic Cloud (LMC) disk using classical Cepheids. Our analysis is based on optical (I,V; OGLE-IV), near-infrared (NIR: J,H,Ks) and mid-infrared (MIR: w1; WISE) mean magnitudes. By adopting new templates ... More
New R Coronae Borealis stars discovered in OGLE-III Galactic Bulge fields from their mid- and near- infrared propertiesJul 06 2010Mar 16 2011An R Coronae Borealis (RCB) star is a rare type of supergiant star that is increasingly thought to be the evolved merger product of two white dwarfs. Recently, many of them have been found distributed in a thin disk structure embedded inside the Galactic ... More
Mass and p-factor of the type II Cepheid OGLE-LMC-T2CEP-098 in a binary systemApr 25 2017We present the results of a study of the type II Cepheid ($P_{puls} = 4.974 d$) in the eclipsing binary system OGLE-LMC-T2CEP-098 ($P_{orb} = 397.2 d$). The Cepheid belongs to the peculiar W Vir group, for which the evolutionary status is virtually unknown. ... More
Blazhko-type modulation in the double-mode RR Lyrae stars of the OGLE Galactic bulge collectionNov 10 2014Dec 16 2014We present the analysis of Blazhko-type modulation in double-mode RR Lyrae (RRd) stars found in the OGLE photometry of the Galactic bulge. Modulation is detected in 15 stars. Most of them have non-typical period ratio of the radial modes. In the Petersen ... More
V1309 Scorpii: merger of a contact binaryDec 01 2010Feb 10 2011Stellar mergers are expected to take place in numerous circumstences in the evolution of stellar systems. In particular, they are considered as a plausible origin of stellar eruptions of the V838 Mon type. V1309 Sco is the most recent eruption of this ... More
OGLE-2013-BLG-0578L: Microlensing Binary Composed of A Brown Dwarf And An M DwarfMar 11 2015Determining physical parameters of binary microlenses is hampered by the lack of information about the angular Einstein radius due to the difficulty of resolving caustic crossings. In this paper, we present the analysis of the binary microlensing event ... More
Eclipsing Binaries with Classical Cepheid Component in the Magellanic SystemJan 07 2016We present a census of eclipsing binary systems with classical Cepheid as a component. All such systems known were found in the OGLE collection of classical Cepheids in the Magellanic System. We extend the list of potential candidates adding four new ... More
The Dusty Aftermath of the V1309 Sco Binary MergerJan 08 2013Jan 10 2013We present mid-IR photometry and spectra of the merged binary V1309 Sco taken between 18 and 23 months after outburst. Strong mid-IR emission and a solid state absorption feature indicate the presence of a significant amount of dust in the circumstellar ... More
OGLE Collection of Galactic CepheidsOct 22 2018We present here a new major part of the OGLE Collection of Variable Stars - OGLE Collection of Galactic Cepheids. The new dataset was extracted from the Galaxy Variability Survey images - a dedicated large-scale survey of the Galactic disk and outer bulge ... More
Three-Dimensional Distributions of Type II Cepheids and Anomalous Cepheids in the Magellanic Clouds. Do these Stars Belong to the Old, Young or Intermediate-Age Population?Sep 05 2018Oct 24 2018The nature of type II Cepheids and anomalous Cepheids is still not well known and their evolutionary channels leave many unanswered questions. We use complete collection of classical pulsating stars in the Magellanic Clouds discovered by the OGLE project, ... More
Gaia and Variable StarsNov 24 2016We present a comparison of the Gaia DR1 samples of pulsating variable stars - Cepheids and RR Lyrae type - with the OGLE Collection of Variable Stars aiming at the characterization of the Gaia mission performance in the stellar variability domain. Out ... More
OGLE-ing the Magellanic System: Photometric Metallicity from Fundamental Mode RR Lyrae StarsJul 29 2016Nov 08 2016In an era of extensive photometric observations, the catalogs of RR Lyr type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to investigate ... More
OGLE-ing the Magellanic System: Photometric Metallicity from Fundamental Mode RR Lyrae StarsJul 29 2016In an era of extensive photometric observations, the catalogs of RR Lyrae type variable stars number tens of thousands of objects. The relation between the iron abundance [Fe/H] and the Fourier parameters of the stars light curve allows us to investigate ... More
Analysis of photometric uncertainties in the OGLE-IV Galactic Bulge microlensing survey dataApr 07 2016We present a statistical assessment of both, observed and reported, photometric uncertainties in the OGLE-IV Galactic bulge microlensing survey data. This dataset is widely used for the detection of variable stars, transient objects, discovery of microlensing ... More
The OGLE Collection of Variable Stars. Over 45 000 RR Lyrae Stars in the Magellanic SystemJun 08 2016Jul 14 2016We present the largest collection of RR Lyrae stars in the Magellanic System and in its foreground. The sample consists of 45 451 RR Lyr stars, of which 39 082 were detected toward the Large Magellanic Cloud and 6369 toward the Small Magellanic Cloud. ... More
The Variable Stars from the OGLE-III Shallow Survey in the Large Magellanic CloudJun 20 2013We describe variable stars found in the data collected during the OGLE-III Shallow Survey covering the I-band magnitude range from 9.7 mag to 14.5 mag. The main result is the extension of period--luminosity relations for Cepheids up to 134 days. We also ... More
A New 3-D Picture of the Milky Way with Classical CepheidsJun 27 2018Aug 16 2018The global view of the Milky Way as a barred spiral galaxy was inferred from various tracers, e.g., star counts or radio maps of Galactic gas, as well as from our extrapolation of structures seen in other galaxies. However, distances to these tracers ... More
Extracting Microlensing Signals from K2 Campaign 9Apr 27 2017Aug 20 2017The reduction of the \emph{K2}'s Campaign 9 (K2C9) microlensing data is challenging mostly because of the very crowded field and the unstable pointing of the spacecraft. In this work, we present the first method that can extract microlensing signals from ... More
OGLE-2012-BLG-0563Lb: a Saturn-mass Planet around an M Dwarf with the Mass Constrained by Subaru AO imagingJun 29 2015Jan 26 2016We report the discovery of a microlensing exoplanet OGLE-2012-BLG-0563Lb with the planet-star mass ratio ~1 x 10^{-3}. Intensive photometric observations of a high-magnification microlensing event allow us to detect a clear signal of the planet. Although ... More
A Terrestrial Planet in a ~1 AU Orbit Around One Member of a ~15 AU BinaryJul 04 2014We detect a cold, terrestrial planet in a binary-star system using gravitational microlensing. The planet has low mass (2 Earth masses) and lies projected at $a_{\perp,ph}$ ~ 0.8 astronomical units (AU) from its host star, similar to the Earth-Sun distance. ... More
Physical parameters and the projection factor of the classical Cepheid in the binary system OGLE-LMC-CEP-0227Aug 23 2013A novel method of analysis of double-lined eclipsing binaries containing a radially pulsating star is presented. The combined pulsating-eclipsing light curve is built up from a purely eclipsing light curve grid created using an existing modeling tool. ... More
The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in the Large Magellanic Cloud. Point source classification ISep 29 2010We present the classification of 197 point sources observed with the Infrared Spectrograph in the SAGE-Spec Legacy program on the Spitzer Space Telescope. We introduce a decision-tree method of object classification based on infrared spectral features, ... More
OGLE Collection of Star Clusters. New Objects in the Outskirts of the Large Magellanic CloudSep 26 2016The Magellanic System (MS), consisting of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Magellanic Bridge (MBR), contains diverse sample of star clusters. Their spatial distribution, ages and chemical abundances may provide ... More
Spitzer as Microlens Parallax Satellite: Mass Measurement for the OGLE-2014-BLG-0124L Planet and its Host StarOct 15 2014We combine Spitzer and ground-based observations to measure the microlens parallax vector ${\mathbf \pi}_{\rm E}$, and so the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. ... More
Anomalous Double-Mode RR Lyrae Stars in the Magellanic CloudsAug 01 2016We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars have been extracted from the latest edition of the OGLE collection of RR Lyrae variables in the Magellanic ... More
OGLE-BLG182.1.162852: An Eclipsing Binary with a Circumstellar DiskOct 09 2014We present the discovery of a plausible disk-eclipse system OGLE-BLG182.1.162852. The OGLE light curve for OGLE-BLG182.1.162852 shows three episodes of dimming by $I \simeq 2 - 3$ magnitudes, separated by 1277 days. The shape of the light curve during ... More
Intriguing triple-mode RR Lyrae star with period doublingNov 11 2014Dec 22 2014We report the discovery of an intriguing triple-mode RR Lyrae star found in the OGLE Galactic bulge collection, OGLE-BLG-RRLYR-24137. In the OGLE catalog the star was identified as RRd star - double-mode pulsator, pulsating simultaneously in the fundamental ... More
OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using RR Lyrae StarsNov 08 2016We present a three-dimensional analysis of a sample of 22 859 type $ab$ RR Lyrae stars in the Magellanic System from the OGLE-IV Collection of RR Lyrae stars. The distance to each object was calculated based on its photometric metallicity and a theoretical ... More
A Gravitationally Lensed Quasar Discovered in OGLEJan 25 2018We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the $\sim$670 sq. deg area encompassing the Magellanic Clouds. The source was selected as one of $\sim$60 ... More
$Spitzer$ Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-Rotating Low-Mass Brown DwarfMay 22 2018Jan 18 2019The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all ... More
OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using RR Lyrae StarsNov 08 2016Jul 10 2017We present a three-dimensional analysis of a sample of 22 859 type $ab$ RR Lyrae stars in the Magellanic System from the OGLE-IV Collection of RR Lyrae stars. The distance to each object was calculated based on its photometric metallicity and a theoretical ... More
First Space-based Microlens Parallax Measurement of an Isolated Star: Spitzer Observations of OGLE-2014-BLG-0939Oct 20 2014Nov 23 2014We present the first space-based microlens parallax measurement of an isolated star. From the striking differences in the lightcurve as seen from Earth and from Spitzer (~1 AU to the West), we infer a projected velocity v_helio,projected ~ 250 km/s, which ... More
$12\;660$ spotted stars toward the OGLE Galactic bulge fieldsMar 13 2019We present the discovery and statistical analysis of $12\;660$ spotted variable stars toward and inside the Galactic bulge from over two-decade-long Optical Gravitational Lensing Experiment (OGLE) data. We devise a new method of dereddening of individual ... More
OGLE Collection of Star Clusters. New Objects in the Magellanic Bridge and the Outskirts of the Small Magellanic CloudJan 17 2018The Magellanic System (MS) encompasses the nearest neighbors of the Milky Way, the Large (LMC) and Small (SMC) Magellanic Clouds, and the Magellanic Bridge (MBR). This system contains a diverse sample of star clusters. Their parameters, such as the spatial ... More
OGLE-ing the Magellanic System: Stellar populations in the Magellanic BridgeMay 28 2014Sep 30 2014We report the discovery of a young stellar bridge, that forms a continuous connection between the Magellanic Clouds. This finding is based on number density maps for stellar populations found in data gathered by OGLE-IV, that fully cover over 270 deg^2 ... More
OGLE-ing the Magellanic System: RR Lyrae Stars in the BridgeApr 16 2019We use the extended and updated OGLE Collection of Variable Stars to thoroughly analyze distribution of RR Lyrae stars in the Magellanic Bridge. We use photometric metallicities to derive absolute Wesenheit magnitude and then individual distance of each ... More
OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using Classical CepheidsFeb 29 2016Jul 12 2016We analyzed a sample of 9418 fundamental-mode and first-overtone Classical Cepheids from the OGLE-IV Collection of Classical Cepheids. The distance to each Cepheid was calculated using the period-luminosity relation for the Wesenheit magnitude, fitted ... More
MOA-2013-BLG-220Lb: Massive Planetary Companion to Galactic-Disk HostMar 10 2014May 30 2014We report the discovery of MOA-2013-BLG-220Lb, which has a super-Jupiter mass ratio $q=3.01\pm 0.02\times 10^{-3}$ relative to its host. The proper motion, $\mu=12.5\pm 1\, {\rm mas}\,{\rm yr}^{-1}$, is one of the highest for microlensing planets yet ... More
Reanalyses of Anomalous Gravitational Microlensing Events in the OGLE-III Early Warning System Database with Combined DataFeb 24 2015Mar 02 2015We 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, ... More
An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per centMar 08 2013In the era of precision cosmology it is essential to determine the Hubble Constant with an accuracy of 3% or better. Currently, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC) which as the second nearest ... More
Space-based Microlens Parallax Observation As a Way to Resolve the Severe Degeneracy between Microlens-parallax and Lens-orbital EffectJun 04 2016In this paper, we demonstrate the severity of the degeneracy between the microlens-parallax and lens-orbital effects by presenting the analysis of the gravitational binary-lens event OGLE-2015-BLG-0768. Despite the obvious deviation from the model based ... More
New R Coronae Borealis and DY Persei Star Candidates and Other Related Objects Found in Photometric SurveysJun 25 2014We have carried out a search for new R Coronae Borealis (RCB) variables using the publicly accessible data from various photometric sky surveys and-whenever available-AAVSO visual data. Candidates were selected from Tisserand`s "Catalogue enriched with ... More
OGLE16aaa - a Signature of a Hungry Super Massive Black HoleJun 09 2016Oct 12 2016We present the discovery and first three months of follow-up observations of a currently on-going unusual transient detected by the OGLE-IV survey, located in the centre of a galaxy at redshift z=0.1655. The long rise to absolute magnitude of -20.5 mag, ... More
OGLE16aaa - a Signature of a Hungry Super Massive Black HoleJun 09 2016We present the discovery and first three months of follow-up observations of a currently on-going unusual transient detected by the OGLE-IV survey, located in the centre of a galaxy at redshift z=0.1655. The long rise to absolute magnitude of -20.5 mag, ... More
Discovery of the massive overcontact binary VFTS 352: Evidence for enhanced internal mixingSep 29 2015The contact phase expected to precede the coalescence of two massive stars is poorly characterized due to the paucity of observational constraints. Here we report on the discovery of VFTS 352, an O-type binary in the 30 Doradus region, as the most massive ... More
Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky WayNov 12 2015The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been ... More
OGLE-2015-BLG-0051/KMT-2015-BLG-0048Lb: a Giant Planet Orbiting a Low-mass Bulge Star Discovered by High-cadence Microlensing SurveysJun 30 2016We 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 ... More
An X-Shooter view of the symbiotic star [JD2002] 11Aug 01 2015We aimed to verify the nature and derive the basic parameters of the symbiotic star candidate [JD2002] 11. For this purpose, we obtained and analysed an X-Shooter spectrum of [JD2002] 11. We also used optical and infrared photometry available for the ... More
A Super-Jupiter orbiting a late-type star: A refined analysis of microlensing event OGLE-2012-BLG-0406Oct 09 2013Dec 05 2013We 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 ... More
Microlensing Discovery of a Population of Very Tight, Very Low-mass Binary Brown DwarfsFeb 18 2013Mar 20 2013Although 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 ... More
Characterizing Low-Mass Binaries From Observation of Long Time-scale Caustic-crossing Gravitational Microlensing EventsApr 13 2012Jun 13 2012Despite 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 ... More
Discovery of two quasars at $z=5$ from the OGLE SurveyOct 19 2018We have used deep Optical Gravitational Lensing Experiment (OGLE-IV) images ($V \lesssim 23$ mag, $I \lesssim 23$ mag at $3\sigma$) of the Magellanic System, encompassing an area of $\sim$670 deg$^2$, to perform a search for high-$z$ quasar candidates. ... More
Spitzer IRAC Photometry for Time Series in Crowded FieldsAug 31 2015Oct 13 2015We develop a new photometry algorithm that is optimized for $Spitzer$ time series in crowded fields and that is particularly adapted to faint and/or heavily blended targets. We apply this to the 170 targets from the 2015 $Spitzer$ microlensing campaign ... More
OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensingApr 16 2019We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 $Spitzer$ microlensing campaign. This event is remarkable because its source is photometrically variable. We perform an asteroseismic analysis of the source star and find that it is ... More
OGLE-2014-BLG-1112LB: A Microlensing Brown Dwarf Detected Through the Channel of a Gravitational Binary-Lens EventMay 30 2017Due to the nature depending on only the gravitational field, microlensing, in principle, provides an important tool to detect faint and even dark brown dwarfs. However, the number of identified brown dwarfs is limited due to the difficulty of the lens ... More
Spitzer Microlensing parallax reveals two isolated stars in the Galactic bulgeApr 25 2019We report the mass and distance measurements of two single-lens events from the 2017 Spitzer microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis ... More
OGLE-2015-BLG-0196: Ground-based Gravitational Microlens Parallax Confirmed By Space-Based ObservationNov 08 2016In 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 ... More
The OGLE-III planet detection efficiency from six years of microlensing observations (2003 to 2008)Feb 08 2016We 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 ... More
The VLT-FLAMES Tarantula survey XX. The nature of the X-ray bright emission line star VFTS 399Mar 03 2015The stellar population of the 30 Doradus star-forming region in the Large Magellanic Cloud contains a subset of apparently single, rapidly rotating O-type stars. The physical processes leading to the formation of this cohort are currently uncertain. One ... More
OGLE-2017-BLG-0537: Microlensing Event with a Resolvable Lens in $\lesssim 5$ years from High-resolution Follow-up ObservationsJun 21 2018We present the analysis of the binary-lens microlensing event OGLE-2017-BLG-0537. The light curve of the event exhibits two strong caustic-crossing spikes among which the second caustic crossing was resolved by high-cadence surveys. It is found that the ... More
OGLE-2016-BLG-0596Lb: High-Mass Planet From High-Magnification Pure-Survey Microlensing EventJul 17 2016We 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 ... More
OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing DegeneracyFeb 27 2018Apr 05 2018We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor ... More
OGLE-2008-BLG-355Lb: A Massive Planet around A Late type StarMar 27 2014We report the discovery of a massive planet OGLE-2008-BLG-355Lb. The light curve analysis indicates a planet:host mass ratio of q = 0.0118 +/- 0.0006 at a separation of 0.877 +/- 0.010 Einstein radii. We do not measure a significant microlensing parallax ... More
OGLE-2016-BLG-0596Lb: High-Mass Planet From High-Magnification Pure-Survey Microlensing EventJul 17 2016Feb 20 2017We 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 ... More
OGLE-2017-BLG-1522: A giant planet around a brown dwarf located in the Galactic bulgeMar 14 2018We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively short event timescale of $t_{\rm E} \sim 7.5$ days. The ... More
MOA-2008-BLG-379Lb: A Massive Planet from a High Magnification Event with a Faint SourceNov 14 2013Dec 17 2013We 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 ... More
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky WayFeb 09 2017Jul 10 2017We present a detailed elemental abundance study of 90 F and G dwarf, turn-off and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11 elements (Na, ... More
MOA 2011-BLG-028Lb: a Neptune-mass Microlensing Planet in the Galactic BulgeDec 10 2015We 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 ... More
Bridge between Hadrodynamics \& HEP: Regional CP Violation in Beauty \& Charm DecaysAug 23 2016There is a long way from `accuracy' to `precision' about {\bf CP} asymmetries in the decays of beauty \& charm hadrons. (a) We have to apply consistent parametrization of the CKM matrix. (b) Probing many-body final states (FS) is {\em not} a back-up for ... More
Memorial Contribution about Kolya Uraltsev's Talk at 2012 Workshop $B\to D**$Jul 02 2013Jul 14 2013Uraltev has given us a deeper understanding of the forces underlying the data from beauty and charm hadrons for the last 35 years and neutron EDM in the future -- in particular about non-perturbative QCD. At the Workshop in the November 2012 before his ... More
The Sybils' Advice on Charm (and $τ$ Leptons)Apr 05 2006The importance of future studies of charm and $\tau$ decays is emphasized as probes of New Physics: the most powerful tools are \cp asymmetries in charm and $\tau$ decays both in partial widths and final state distributions. While these searches for \cp ... More
The Battle of Albuera, the FC Liverpool and the Standard ModelMar 12 2006The Standard Model despite its well-known short comings is unlikely to yield without offering stubborn resistance. There are compelling arguments that New Physics lurks around the TeV scale. Continuing comprehensive studies of beauty, $\tau$ and charm ... More
Quo Vadis, Fascinum?Aug 14 1995The recent progress in our understanding of heavy-flavour decays allows us to define more reliably which future measurements on charm decays are needed to further advance our understanding of QCD and to get our theoretical tools ready for treating beauty ... More
Beauty Physics in the Next 15 Years -- an Itinerary for a Long Journey towards an Essential GoalJul 06 1994After re-stating why beauty physics is so special and sketching its present status I attempt to map out an itinerary for the next fifteen years. The basic elements are listed for a research program that allows to define and probe the KM unitarity triangle ... More
Weak Decays Of Charm Hadrons: The Next Lesson On QCD -- And Possibly More!Nov 01 1993Second-generation theoretical technologies -- heavy quark expansions, QCD sum rules and QCD simulations on the lattice -- are arriving on the scene, allowing a treatment of charm decays that is genuinely based on QCD. The availability of those theoretical ... More
On the Brink of Major Discoveries in Weak Charm Decays -- a Bismarckian Chance to Make HistoryOct 15 2007The recently obtained strong evidence for $D^0 - \bar D^0$ oscillations from the $B$ factories provides an important benchmark in our search for New Physics in charm transitions. While the theoretical verdict on the observed values of $x_D$ and $y_D$ ... More