- ID:
- ivo://CDS.VizieR/J/PASJ/58/389
- Title:
- O/Fe abundances of 15 RR Lyrae
- Short Name:
- J/PASJ/58/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to study how the conventional spectroscopic method based on the equivalent widths of the Fe I and Fe II lines effectively applies to determining the atmospheric parameters (Teff, logg, v_t_, [Fe/H]) of RR Lyrae variables and how accurately the abundances can be established from such constructed model atmospheres, we analyzed 15 high-dispersion spectrograms of RR Lyr, DX Del, DH Peg, and VY Ser taken at several different phases by using the HDS spectrograph of the Subaru Telescope, and examined the consistency of the resulting phase-to-phase abundances.
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- ID:
- ivo://CDS.VizieR/J/ApJ/812/136
- Title:
- OGLE-2013-BLG-446 photometry
- Short Name:
- J/ApJ/812/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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_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_{Earth}_) 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/504/5907
- Title:
- OGLE Bulge short-period sample
- Short Name:
- J/MNRAS/504/5907
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third of a series of papers that presents an algorithm to search for close binaries with massive, possibly compact, unseen secondaries. The detection of such a binary is based on identifying a star that displays a large ellipsoidal periodic modulation, induced by tidal interaction with its companion. In the second paper of the series, we presented a simple approach to derive a robust modified minimum mass ratio (mMMR), based on the observed ellipsoidal amplitude, without knowing the primary mass and radius, assuming the primary fills its Roche lobe. The newly defined mMMR is always smaller than the actual mass ratio. Therefore, a binary with an mMMR larger than unity is a good candidate for having a massive secondary, which might be a black hole or a neutron star. This paper considers 10956 OGLE short-period ellipsoidals observed towards the Galactic bulge. We re-analyse their modulation and identify 136 main-sequence systems with mMMR significantly larger than unity as candidates for having compact-object secondaries, assuming their observed periodic modulations reflect indeed the ellipsoidal effect. Obviously, one needs follow-up observations to find out the true nature of these companions.
- ID:
- ivo://CDS.VizieR/J/AcA/51/317
- Title:
- OGLE DIA. Catalog of LMC and SMC images
- Short Name:
- J/AcA/51/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first edition of a catalog of variable stars found in the Magellanic Clouds using OGLE-II data obtained during four years: 1997-2000. The catalog covers about 7 square degrees of the sky - 21 fields in the Large Magellanic Cloud and 11 fields in the Small Magellanic Cloud. All variables were found with the Difference Image Analysis (DIA) software. The catalog is divided into two sections. The DC section contains FITS reference images (obtained by co-adding 20 best frames for each field) and profile photometry (DOPHOT) of all variable stars on those images. The AC section contains flux variations and magnitudes of detected variable stars obtained with DIA as well as with DOPHOT. The errors of magnitude measurements are 0.005mag for the brightest stars (I<16mag) then grow to 0.08mag at 19mag stars and to 0.3mag at 20.5mag. Typically, there are about 400 I-band data points and about 30 V and B-band data points for more than 68 000 variables. The stars with high proper motions were excluded from this catalog and will be presented in a separate paper. A detailed analysis and classification of variable stars will be presented elsewhere. The catalog is available in electronic form via FTP and through WWW interface from the OGLE Internet archive. The FTP catalog contains approximately 2 GB of data.
- ID:
- ivo://CDS.VizieR/J/ApJ/651/197
- Title:
- OGLE fundamental-mode RR Lyrae in Galactic Bulge
- Short Name:
- J/ApJ/651/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 1888 fundamental-mode RR Lyrae stars detected in the Galactic bulge fields of the second phase of the Optical Gravitational Lensing Experiment (OGLE). The catalog includes basic parameters of the light curves, identifications of Blazhko frequencies, V-I colors at minimum light (for most stars), and other information for each star. We detect a high rate of incidence of the Blazhko phenomenon (at least 27.6%), including unprecedentedly many frequency triplets, which we attribute to our sensitive search method. We find that the minimum light V-I color (useful as a reddening indicator) grows slowly redder with increasing period and exhibits a star-to-star scatter of approximately 0.07mag. We use this color to evaluate the zero-point accuracy of the reddening map of the Galactic bulge derived from OGLE data and find that in addition to low-level random errors or resolution effects (responsible for much of the scatter), the map may systematically over-represent E(V-I) by approximately 0.05mag in most fields.
- ID:
- ivo://CDS.VizieR/J/AcA/62/219
- Title:
- OGLE: Gaia South Ecliptic Pole Field
- Short Name:
- J/AcA/62/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of the Gaia South Ecliptic Pole (GSEP) field, 5.3 square degrees area around the South Ecliptic Pole on the outskirts of the LMC, based on the data collected during the fourth phase of the Optical Gravitational Lensing Experiment, OGLE-IV. The GSEP field will be observed during the commissioning phase of the ESA Gaia space mission for testing and calibrating the Gaia instruments. We provide the photometric maps of the GSEP region containing the mean VI photometry of all detected stellar objects and their equatorial coordinates. We show the quality and completeness of the OGLE-IV photometry and color-magnitude diagrams of this region. We conducted an extensive search for variable stars in the GSEP field leading to the discovery of 6789 variable stars. In this sample we found 132 classical Cepheids, 686 RR Lyr type stars, 2819 long-period, and 1377 eclipsing variables. Several objects deserving special attention were also selected, including a new classical Cepheid in a binary eclipsing system.
- ID:
- ivo://CDS.VizieR/II/213
- Title:
- OGLE Galactic Bulge periodic variables
- Short Name:
- II/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Catalog of Periodic Variable Stars in the Galactic Bulge. The Catalog is based on observations collected during the OGLE (Optical Graviational Lensing Experiment) microlensing search: (1) 213 periodic variable stars brighter than Imag=18mag: 31 pulsating, 116 eclipsing and 66 miscellaneous type variables from the Baade's Window BWC field are presented. (2) 800 variable stars found in four Baade's Window fields BW1, BW2, BW3 and BW4 are presented. Among them 71 are classified as pulsating, 465 as eclipsing and 264 as miscellaneous type. (3) 644 variable stars: 64 pulsating, 352 eclipsing and 228 miscellaneous type were detected in four Baade's Window fields BW5, BW6, BW7 and BW8. Analysis of periodic variable stars found in overlapping regions of the Baade's Window fields yields an average completeness of the Catalog equal to about 80% of periodic variables objects registered in the OGLE databases and about 65% of all periodic variable stars in the observed region of the sky. (4) 631 variable stars: 59 pulsating, 348 eclipsing and 224 miscellaneous type were detected in third Baade's Window fields BW9, BW10, and BW11. (5) 574 variables stars: 44 pulsating, 369 eclipsing and 161 miscellaneous type were detected in four fields located symmetrically in the galactic latitude around the Galactic center: MM5-A, MM5-B, MM7-A and MM7-B.
- ID:
- ivo://CDS.VizieR/J/AcA/67/297
- Title:
- OGLE Galactic center Cepheids and RR Lyrae
- Short Name:
- J/AcA/67/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a collection of classical, type II, and anomalous Cepheids detected in the OGLE fields toward the Galactic center. The sample contains 87 classical Cepheids pulsating in one, two or three radial modes, 924 type II Cepheids divided into BL Her, W Vir, peculiar W Vir, and RV Tau stars, and 20 anomalous Cepheids - first such objects found in the Galactic bulge. Additionally, we upgrade the OGLE Collection of RR Lyr stars in the Galactic bulge by adding 828 newly identified variables. For all Cepheids and RR Lyr stars, we publish time-series VI photometry obtained during the OGLE-IV project, from 2010 through 2017. We discuss basic properties of our classical pulsators: their spatial distribution, light curve morphology, period-luminosity relations, and position in the Petersen diagram. We present the most interesting individual objects in our collection: a type II Cepheid with additional eclipsing modulation, W Vir stars with the period doubling effect and the RVb phenomenon, a mode-switching RR Lyr star, and a triple-mode anomalous RRd star.
- ID:
- ivo://CDS.VizieR/J/AcA/68/315
- Title:
- OGLE Galactic Cepheids
- Short Name:
- J/AcA/68/315
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We 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 conducted by the OGLE project since 2013. The OGLE collection contains 2721 Cepheids of all types - classical, type II and anomalous. It more than doubles the number of known Galactic classical Cepheids. Due to the long-term monitoring and large number of epochs the selected sample is very pure, generally free from contaminating stars of other types often mimicking Cepheids. Its completeness is high at 90% level for classical Cepheids - tested using recent samples of Galactic Cepheids: ASAS-SN, ATLAS, Gaia DR2 and Wise catalog of variable stars. Our comparisons indicate that the completeness of the two latter datasets, Gaia DR2 andWise catalog, is very low, at <10% level in the magnitude range of the OGLE GVS survey (10.8<I<19.5mag). Both these samples are severely contaminated by non-Cepheids (the purity is 67% and 56%, respectively). We also present several interesting objects found in the new OGLE Collection - multi-mode pulsators, first Galactic candidates for eclipsing systems containing Cepheid, a binary Cepheid candidate. New OGLE Collection of Galactic Cepheids is available for the astronomical community from the OGLE Internet Archive in similar form as previous parts of the OGLE Collection of Variable Stars.
- ID:
- ivo://CDS.VizieR/J/AcA/51/221
- Title:
- OGLE-II. Cepheids in IC 1613
- Short Name:
- J/AcA/51/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of the search for Cepheids in the galaxy IC 1613 carried out as a sub-project of the OGLE-II microlensing survey. 138 Cepheids were found in the 14.2'x14.2' region in the center of the galaxy. We present light curves, VI photometry and basic data for all these objects, as well as color-magnitude diagram of the observed field.
