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- ID:
- ivo://CDS.VizieR/J/AJ/159/262
- Title:
- OGLE/KMTnet VI bands photomerty of OGLE-2019-BLG-0551
- Short Name:
- J/AJ/159/262
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- High-cadence observations of the Galactic bulge by the microlensing surveys led to the discovery of a handful of extremely short-timescale microlensing events that can be attributed to free-floating or wide-orbit planets. Here, we report the discovery of another strong free-floating planet candidate, which was found from the analysis of the gravitational microlensing event OGLE-2019-BLG-0551. The light curve of the event is characterized by a very short duration (<~3days) and a very small amplitude (<~0.1mag). From modeling of the light curve, we find that the Einstein timescale, t_E_=0.381{+/-}0.017day, is much shorter, and the angular Einstein radius, {theta}_E_=4.35{+/-}0.34{mu}mas, is much smaller than those of typical lensing events produced by stellar-mass lenses (t_E_~20days, {theta}_E_~0.3mas), indicating that the lens is very likely to be a planetary-mass object. We conduct an extensive search for possible signatures of a companion star in the light curve of the event, finding no significant evidence for the putative host star. For the first time, we also demonstrate that the angular Einstein radius of the lens does not depend on blending in the low-magnification events with strong finite source effects.
2493. OGLE LMC BVI photometry
- ID:
- ivo://CDS.VizieR/J/AcA/50/307
- Title:
- OGLE LMC BVI photometry
- Short Name:
- J/AcA/50/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the BVI photometric maps of the Large Magellanic Cloud. They contain BVI photometry and astrometry of more than 7 million stars from the central parts of the LMC. The data were collected during the second phase of the OGLE microlensing project. We discuss the accuracy of the data and present color-magnitude diagrams of all 26 fields observed by OGLE in the LMC. The BVI maps of the LMC are accessible electronically for the astronomical community from the OGLE Internet archive.
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/953
- Title:
- OGLE-LMC-CEP-0227 RV and VI[3.6] curves
- Short Name:
- J/MNRAS/436/953
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 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 modelling tool. For every pulsation phase, the instantaneous radius and surface brightness are taken into account, being calculated from the disentangled radial velocity curve of the pulsating star and from its out-of-eclipse pulsational light curve and the light ratio of the components, respectively. The best model is found using the Markov chain Monte Carlo method. The method is applied to the eclipsing binary Cepheid OGLE-LMC-CEP-0227 (P_puls_=3.80d, P_orb_=309d). We analyse a set of new spectroscopic and photometric observations for this binary, simultaneously fitting OGLE V-band, I-band and Spitzer 3.6{mu}m photometry. We derive a set of fundamental parameters of the system significantly improving the precision comparing to the previous results obtained by our group. The Cepheid mass and radius are M_1_=4.165+/-0.032M_{sun}_ and R_1_=34.92+/-0.34R{sun}, respectively. For the first time a direct, geometrical and distance-independent determination of the Cepheid projection factor is presented. The value p=1.21+/-0.03(stat.)+/-0.04(syst.) is consistent with theoretical expectations for a short-period Cepheid and interferometric measurements for {delta} Cep. We also find a very high value of the optical limb darkening coefficients for the Cepheid component, in strong disagreement with theoretical predictions for static atmospheres at a given surface temperature and gravity.
- ID:
- ivo://CDS.VizieR/J/ApJ/868/30
- Title:
- OGLE LMC-T2CEP-211 eclipsing binary LCs and RVs
- Short Name:
- J/ApJ/868/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of a peculiar W Virginis (pWVir) type II Cepheid, OGLE-LMC-T2CEP-211 (P_puls_=9.393d), in a double-lined binary system (P_orb_=242d), which shed light on virtually unknown evolutionary status and structure of pWVir stars. The dynamical mass of the Cepheid (first ever for a type II Cepheid) is 0.64+/-0.02M_{sun}_, and the radius R=25.1+/-0.3R_{sun}_. The companion is a massive (5.67M_{sun}_) main-sequence star obscured by a disk. Such a configuration suggests a mass transfer in the system history. We found that originally the system (P_orb_^init^=12d) was composed of 3.5 and 2.8M_{sun}_ stars, with the current Cepheid being more massive. The system age is now ~200Myr, and the Cepheid is almost completely stripped of hydrogen, with helium mass of ~92% of the total mass. It finished transferring the mass 2.5Myr ago and is evolving toward lower temperatures passing through the instability strip. Comparison with observations indicates a reasonable 2.7x10^-8^M_{sun}_/yr mass loss from the Cepheid. The companion is most probably a Be main-sequence star with T=22000K and R=2.5R_{sun}_. Our results yield a good agreement with a pulsation theory model for a hydrogen-deficient pulsator, confirming the described evolutionary scenario. We detected a two-ring disk (R_disk_~116R_{sun}_) and a shell (R_shell_~9R_{sun}_) around the companion, which is probably a combination of the matter from the past mass transfer, the mass being lost by the Cepheid owing to wind and pulsations, and a decretion disk around a rapidly rotating secondary. Our study, together with observational properties of pWVir stars, suggests that the majority of them are products of a similar binary evolution interaction.
- ID:
- ivo://CDS.VizieR/J/AJ/161/270
- Title:
- OGLE, MOA & KMTNet RI light curve of KMT-2019-BLG-1715
- Short Name:
- J/AJ/161/270
- Date:
- 16 Mar 2022 00:06:48
- Publisher:
- CDS
- Description:
- We investigate the gravitational microlensing event KMT-2019-BLG-1715, the light curve of which shows two short-term anomalies from a caustic-crossing binary-lensing light curve: one with a large deviation and the other with a small deviation. We identify five pairs of solutions, in which the anomalies are explained by adding an extra lens or source component in addition to the base binary-lens model. We resolve the degeneracies by applying a method in which the measured flux ratio between the first and second source stars is compared with the flux ratio deduced from the ratio of the source radii. Applying this method leaves a single pair of viable solutions, in both of which the major anomaly is generated by a planetary-mass third body of the lens, and the minor anomaly is generated by a faint second source. A Bayesian analysis indicates that the lens comprises three masses: a planet-mass object with ~2.6M_J_ and binary stars of K and M dwarfs lying in the galactic disk. We point out the possibility that the lens is the blend, and this can be verified by conducting high-resolution follow-up imaging for the resolution of the lens from the source.
2497. OGLE RR Lyrae in LMC
- ID:
- ivo://CDS.VizieR/J/AcA/53/93
- Title:
- OGLE RR Lyrae in LMC
- Short Name:
- J/AcA/53/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive at ftp://sirius.astrouw.edu.pl/ogle/ogle2/var_stars/lmc/rrlyr
- ID:
- ivo://CDS.VizieR/J/AcA/48/113
- Title:
- OGLE RR Lyrae VI photometry
- Short Name:
- J/AcA/48/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the mean luminosity of three samples of field RRab Lyr stars observed in the course of the OGLE microlensing experiment: 73 stars from the Galactic bulge and 110 and 128 stars from selected fields in the LMC and SMC, respectively. The fields are the same as in the recent distance determination to the Magellanic Clouds with the red clump stars method by Udalski et al. (1998AcA....48....1U). We determine the relative distance scale Galactic Bulge: 0.194+/-0.010; LMC: 1.00 ; SMC: 1.30+/-0.08. We calibrate our RR Lyr distance scale with the recent calibration of Gould and Popowski (1998ApJ...508..844G) based on statistical parallaxes. We obtain the following distance moduli to the Galactic bulge, LMC and SMC: m-M=14.5+/-0.15, m-M=18.09+/-0.16 and m-M=18.66+/-0.16mag.
2499. OGLE SMC BVI photometry
- ID:
- ivo://CDS.VizieR/J/AcA/48/147
- Title:
- OGLE SMC BVI photometry
- Short Name:
- J/AcA/48/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present three color, BVI maps of the Small Magellanic Cloud. The maps contain precise photometric and astrometric data for about 2.2million stars from the central regions of the SMC bar covering ~2.4 square degrees on the sky. Mean brightness of stars is derived from observations collected in the course of the OGLE-II microlensing search from about 130, 30 and 15 measurements in the I, V and B-bands, respectively. Accuracy of the zero points of photometry is about 0.01mag, and astrometry 0.15arcsec (with possible systematic error up to 0.7arcsec). Color magnitude diagrams of observed fields are also presented. The maps of the SMC are the first from the series of similar maps covering other OGLE fields: LMC, Galactic bulge and Galactic disk. The data are very well suited for many projects, particularly for the SMC which has been neglected photometrically for years.
2500. OGLE SMC clusters
- ID:
- ivo://CDS.VizieR/J/AcA/48/175
- Title:
- OGLE SMC clusters
- Short Name:
- J/AcA/48/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalog of clusters found in the area of ~2.4 square degrees in the central region of the Small Magellanic Cloud. The catalog contains data for 238 clusters, 72 of them are new objects. For each cluster equatorial coordinates, radii, approximate number of members, cross-identification, finding chart and color magnitude diagrams: V-(B-V) and V-(V-I) are provided.