Showing papers by "M. Kubiak published in 2003"
TL;DR: The OGLE-2003-BLG-262 microlensing event as mentioned in this paper was generated by a point-mass lens transiting the face of a K giant source in the Galactic bulge, and the resulting finite-source effects were used to measure the angular Einstein radius, theta_E=195+-17muas, and so constrain the lens mass to the fullwidth half-maximum interval 0.08 < M/M_sun < 0.54.
Abstract: We analyze OGLE-2003-BLG-262, a relatively short, t_E=12.5+-0.1day, microlensing event generated by a point-mass lens transiting the face of a K giant source in the Galactic bulge. We use the resulting finite-source effects to measure the angular Einstein radius, theta_E=195+-17muas, and so constrain the lens mass to the full-width half-maximum interval 0.08 < M/M_sun < 0.54. The lens-source relative proper motion is mu_rel = 27+-2 km/s/kpc. Both values are typical of what is expected for lenses detected toward the bulge. Despite the short duration of the event, we detect marginal evidence for a "parallax asymmetry", but argue that this is more likely to be induced by acceleration of the source, a binary lens, or possibly by statistical fluctuations. Although OGLE-2003-BLG-262 is only the second published event to date in which the lens transits the source, such events will become more common with the new OGLE-III survey in place. We therefore give a detailed account of the analysis of this event to facilitate the study of future events of this type.
370 citations
TL;DR: In this article, the authors present a proper motion (\mu) catalogue of 5,080,236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11 deg.
Abstract: We present a proper motion (\mu) catalogue of 5,080,236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11 deg.
68 citations
01 Dec 2003
TL;DR: In this paper, a proper-motion (μ) catalogue of 5 080 236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11° < l < 11° and -6° < b < 3°, the total area close to 11 deg 2.
Abstract: We present a proper-motion (μ) catalogue of 5 080 236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11° < l < 11° and -6° < b < 3°, the total area close to 11 deg 2 . The proper-motion measurements are based on 138-555 I-band images taken during four observing seasons: 1997-2000. The catalogue stars are in the magnitude range 11 < I < 18 mag. In particular, the catalogue includes red clump giants and red giants in the GB, and main-sequence stars in the Galactic disc. The proper motions up to μ = 500 mas yr -1 were measured with a mean accuracy of 0.8-3.5 mas yr -1 , depending on the brightness of a star. This catalogue may be useful for studying the kinematics of stars in the GB and the Galactic disc.
53 citations
TL;DR: In this article, the authors present 3 years of photometry of the Double Hamburger lensed quasar, HE 1104-1805 AB, obtained on 102 separate nights using the Optical Gravitational Lensing Experiment 1.3 m telescope.
Abstract: We present 3 years of photometry of the Double Hamburger lensed quasar, HE 1104-1805 AB, obtained on 102 separate nights using the Optical Gravitational Lensing Experiment 1.3 m telescope. Both the A and B images show variations, but with substantial differences in the light curves at all time delays. At the 310 day delay reported by Wisotzki and collaborators, the difference light curve has an rms amplitude of 0.060 mag. The structure functions for the A and B images are quite different, with image A more than twice as variable as image B (a factor of 4 in structure function) on timescales of less than a month. Adopting microlensing as a working hypothesis for the uncorrelated variability, the short timescale argues for the relativistic motion of one or more components of the source. We argue that the small amplitude of the fluctuations is due to the finite size of the source with respect to the microlenses.
51 citations
Journal Article•
11 citations
Journal Article•
TL;DR: The photometric data collected by OGLE-III during the 2001 and 2002 observational campaigns aiming at detection of planetary or low-luminosity object transits were corrected for small scale systematic effects using the data pipeline by Kruszewski and Semeniuk and searched again for low amplitude transits as mentioned in this paper.
Abstract: The photometric data collected by OGLE-III during the 2001 and 2002 observational campaigns aiming at detection of planetary or low-luminosity object transits were corrected for small scale systematic effects using the data pipeline by Kruszewski and Semeniuk and searched again for low amplitude transits. Sixteen new objects with small transiting companions, additional to previously found samples, were discovered. Most of them are small amplitude cases which remained undetected in the original data.
Several new objects seem to be very promising candidates for systems containing substellar objects: extrasolar planets or brown dwarfs. Those include OGLE-TR-122, OGLE-TR-125, OGLE-TR-130, OGLE-TR-131 and a few others. Those objects are particularly worth spectroscopic follow-up observations for radial velocity measurements and mass determination. With well known photometric orbit only a few RV measurements should allow to confirm their actual status.
All photometric data of presented objects are available to the astronomical community from the OGLE Internet archive.
10 citations
Posted Content•
TL;DR: The photometric data collected by OGLE-III during the 2001 and 2002 observational campaigns aiming at detection of planetary or low-luminosity object transits were corrected for small scale systematic effects using the data pipeline by Kruszewski and Semeniuk and searched again for low amplitude transits Sixteen new objects with small transiting companions, additional to previously found samples, were discovered Most of them are small amplitude cases which remained undetected in the original data.
Abstract: The photometric data collected by OGLE-III during the 2001 and 2002 observational campaigns aiming at detection of planetary or low-luminosity object transits were corrected for small scale systematic effects using the data pipeline by Kruszewski and Semeniuk and searched again for low amplitude transits Sixteen new objects with small transiting companions, additional to previously found samples, were discovered Most of them are small amplitude cases which remained undetected in the original data
Several new objects seem to be very promising candidates for systems containing substellar objects: extrasolar planets or brown dwarfs Those include OGLE-TR-122, OGLE-TR-125, OGLE-TR-130, OGLE-TR-131 and a few others Those objects are particularly worth spectroscopic follow-up observations for radial velocity measurements and mass determination With well known photometric orbit only a few RV measurements should allow to confirm their actual status
All photometric data of presented objects are available to the astronomical community from the OGLE Internet archive
9 citations
Journal Article•
TL;DR: In this paper, the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud was presented, which were selected with the automatic search algorithm based on an artificial neural network.
Abstract: We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.
6 citations
Posted Content•
TL;DR: In this article, the long term monitoring of the gravitationally lensed quasar HE1104-1805 has been studied and the time delay in the light curves of images A and B was determined to be 157+/-21 days with the variability in the image B light curve leading variability of the image A. The result is in excellent agreement with the earlier determination by Ofek and Maoz.
Abstract: We present results of the long term monitoring of the gravitationally lensed quasar HE1104-1805. The photometric data were collected between August 1997 and January 2002 as a subproject of the OGLE survey.
We determine the time delay in the light curves of images A and B of HE1104-1805 to be equal to 157+/-21 days with the variability in the image B light curve leading variability of the image A. The result is in excellent agreement with the earlier determination by Ofek and Maoz.
OGLE photometry of HE1104-1805 is available to the astronomical community from the OGLE Internet archive.
4 citations
Posted Content•
TL;DR: In this paper, the catalog of RR Lyrae stars from 2.4 square degrees of central parts of the Small Magellanic Cloud (SMC) was presented and the photometric data were collected during four years of the OGLE-II microlensing survey.
Abstract: We present the catalog of RR Lyrae stars from 2.4 square degrees of central parts of the Small Magellanic Cloud (SMC). The photometric data were collected during four years of the OGLE-II microlensing survey. Photometry of each star was obtained using the Difference Image Analysis (DIA) method. The catalog contains 571 objects, including 458 RRab, 56 RRc variables, and 57 double mode RR Lyr stars (RRd). Additionally we attach a list of variables with periods between 0.18-0.26 days, which are probably delta Sct stars. Period, BVI photometry, astrometry, amplitude, and parameters of the Fourier decomposition of the I-band light curve are provided for each object. We also present the Petersen diagram for double mode pulsators.
We found that the SMC RR Lyr stars are fairly uniformly distributed over the studied area, with no clear correlation to any location. The most preferred periods for RRab and RRc stars are 0.589 and 0.357 days, respectively. We noticed significant excess of stars with periods of about 0.29 days, which might be second-overtone RR Lyr stars (RRe). The mean extinction free magnitudes derived for RRab stars are 18.97, 19.45 and 19.73 mag for the I, V and B-band, respectively.
All presented data, including individual BVI observations, are available from the OGLE Internet archive.
3 citations
Posted Content•
TL;DR: In this paper, the OGLE-II photometry supplemented by the MACHO photometry was used to find 64 Beta Cephei stars in the LMC and their periods are generally much longer than observed in stars of this type in the Galaxy.
Abstract: This is a progress report of the study of pulsating main-sequence stars in the LMC. Using the OGLE-II photometry supplemented by the MACHO photometry, we find 64 Beta Cephei stars in the LMC. Their periods are generally much longer than observed in stars of this type in the Galaxy (the median value is 0.27 d compared with 0.17 d in the Galaxy). In 20 stars with short periods attributable to the Beta Cephei-type instability, we also find modes with periods longer than 0.4 d. They are likely low-order g modes, which means that in these stars both kinds of variability, Beta Cephei and SPB, are observed. We also show examples of the multiperiodic SPB stars in the LMC, the first beyond our Galaxy.
Posted Content•
TL;DR: In this paper, the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud was presented, which were selected with the automatic search algorithm based on an artificial neural network.
Abstract: We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.
Journal Article•
TL;DR: In this article, the long term monitoring of the gravitationally lensed quasar HE1104-1805 has been studied and the time delay in the light curves of images A and B was determined to be 157+/-21 days with the variability in the image B light curve leading variability of the image A. The result is in excellent agreement with the earlier determination by Ofek and Maoz.
Abstract: We present results of the long term monitoring of the gravitationally lensed quasar HE1104-1805. The photometric data were collected between August 1997 and January 2002 as a subproject of the OGLE survey.
We determine the time delay in the light curves of images A and B of HE1104-1805 to be equal to 157+/-21 days with the variability in the image B light curve leading variability of the image A. The result is in excellent agreement with the earlier determination by Ofek and Maoz.
OGLE photometry of HE1104-1805 is available to the astronomical community from the OGLE Internet archive.
Journal Article•
TL;DR: In this paper, the location of the newly identified Population II Cepheids in the color-magnitude diagram was analyzed and the position of these objects confirmed recent discovery that the interstellar extinction toward the Galactic bulge might be anomalous.
Abstract: We present I-band light curves of 54 Population II Cepheids identified in the OGLE-II catalog of variable objects in the Galactic bulge fields. Their periods range from a fraction of a day to several days. Their light curves show very close similarity to the light curves of classical Cepheids with periods a few times longer.
We analyze location of the newly identified Population II Cepheids in the color--magnitude diagram. The position of these objects confirms recent discovery that the interstellar extinction toward the Galactic bulge might be anomalous. The slope of the reddening line obtained from our sample is in very good agreement with the earlier one derived with red clump stars and the one derived with RR~Lyr stars in the Galactic bulge.
Our Population II Cepheids follow the same period--luminosity (P--L) relation indicating similar status of these objects. We compare the P--L relation of these stars with the relation of Population II Cepheid detected by the OGLE-II survey in the LMC. Deviations from the P--L relation of the Galactic bulge Cepheids seem to indicate that these objects are located in the Galactic bar similarly to red clump stars.
Posted Content•
TL;DR: The OGLE-III survey as discussed by the authors was conducted in 2002 to detect low-luminosity transits of stars with photometry better than 15 mmag and revealed 62 objects with shallow depth (0.08 mag) flat-bottomed transits.
Abstract: We present results of the second planetary and low-luminosity object transit campaign conducted by the OGLE-III survey. Three fields (35'x35' each) located in the Carina regions of the Galactic disk (l~290) were monitored continuously in February-May 2002. About 1150 epochs were collected for each field. The search for low depth transits was conducted on about 103000 stars with photometry better than 15 mmag. In total, we discovered 62 objects with shallow depth (<0.08 mag) flat-bottomed transits. For each of these objects several individual transits were detected and photometric elements were determined. Also lower limits on radii of the primary and companion were calculated. The 2002 OGLE sample of stars with transiting companions contains considerably more objects that may be Jupiter-sized (R<1.6 R_Jup) compared to our 2001 sample. There is a group of planetary candidates with the orbital periods close to or shorter than one day. If confirmed as planets, they would be the shortest period extrasolar planetary systems. In general, the transiting objects may be extrasolar planets, brown dwarfs, or M-type dwarfs. One should be, however, aware that in some cases unresolved blends of regular eclipsing stars can mimic transits. Future spectral analysis and eventual determination of the amplitude of radial velocity should allow final classification. High resolution spectroscopic follow-up observations are, therefore, strongly encouraged. All photometric data are available from the OGLE Internet archive.
Note added for astro-ph version: One of the best planetary candidates from the OGLE 2001 campaign, OGLE-TR-56, has recently been confirmed as a planetary system by Konacki, Torres, Jha and Sasselov [astro-ph/0301052].