- ID:
- ivo://CDS.VizieR/J/A+A/535/A38
- Title:
- Observations of NOAO Bootes field at 153MHz
- Short Name:
- J/A+A/535/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep, high-resolution radio interferometric observations at 153MHz to complement the extensively studied NOAO Bootes field. We provide a description of the observations, data reduction and source catalog construction. From our single pointing GMRT observation of ~12 hours we obtain a high-resolution (26"x22") image of ~11.3 square degrees, fully covering the Bootes field region and beyond.
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- ID:
- ivo://CDS.VizieR/J/ApJ/720/1691
- Title:
- Observations of the distant Kuiper belt
- Short Name:
- J/ApJ/720/1691
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field survey using the 1.2m Samuel Oschin Telescope at Palomar Observatory. This survey was designed to find the most distant members of the Kuiper Belt and beyond. We searched ~12000deg^2^ down to a mean limiting magnitude of 21.3 in R. A total number of 52 Kuiper Belt objects and Centaurs have been detected, 25 of which were discovered in this survey. Except for the redetection of Sedna, no additional Sedna-like bodies with perihelia greater than 45AU were detected despite sensitivity out to distances of 1000AU. We discuss the implications for a distant Sedna-like population beyond the Kuiper Belt, focusing on the constraints we can place on the embedded stellar cluster environment the early Sun may be have been born in, where the location and distribution of Sedna-like orbits sculpted by multiple stellar encounters is indicative of the birth cluster size. We also report our observed latitude distribution and implications for the size of the plutino population.
- ID:
- ivo://CDS.VizieR/J/ApJS/241/32
- Title:
- OB stars from the LAMOST DR5 spectra
- Short Name:
- J/ApJS/241/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 22901 OB spectra of 16032 stars identified from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 5 (LAMOST DR5) data set. A larger sample of OB candidates are first selected from the distributions in the spectral line indices' space. Then, all 22901 OB spectra are identified by manual inspection. Based on a subsample validation, we find that the completeness of the OB spectra reaches about 89+/-22% for the stars with spectral types earlier than B7, while around 57+/-16% B8-B9 stars are identified. The smaller completeness for late B stars will lead to the difficulty in discriminating them from A0-A1-type stars. The subclasses of the OB samples are determined using the software package MKCLASS. With a careful validation using 646 subsamples, we find that MKCLASS can give fairly reliable subtypes and luminosity classes for most of the OB stars. The uncertainty of the spectral subtype is around 1 subtype, and the uncertainty of the luminosity class is around 1 level. However, about 40% of the OB stars fail to be assigned to any class by MKCLASS, and a few spectra are significantly misclassified by MKCLASS. This is likely because the template spectra of MKCLASS are selected from nearby stars in the solar neighborhood, while the OB stars in this work are mostly located in the outer disk and may have lower metallicities. The rotation of the OB stars may also be responsible for the misclassifications. Moreover, we find that the spectral and luminosity classes of the OB stars located in the Galactic latitude larger than 20{deg} are substantially different with those located in the latitude smaller than 20{deg}, which may either be due to the observational selection effect or may hint a different origin of the high Galactic latitude OB stars.
- 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/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/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/MNRAS/348/1439
- Title:
- OGLE II Galactic center proper motions
- Short Name:
- J/MNRAS/348/1439
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a proper-motion catalogue of 5080236 stars in 49 Optical Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields, covering a range of -11{deg}<l<11{deg} and -6{deg}<b<3{deg}, the total area close to 11deg^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<18mag. 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 pm=500mas/yr were measured with a mean accuracy of 0.8-3.5mas/yr, 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.
- ID:
- ivo://CDS.VizieR/II/322
- Title:
- OGLE-III. Magellanic Clouds stellar proper motions
- Short Name:
- II/322
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of over 6.2million stars with measured proper motions. All these stars are observed in the direction of the Magellanic Clouds within the brightness range 12<I<19mag. Based on these proper motions about 440000 Galactic foreground stars can be selected. Because the proper motions are based on a few hundred epochs collected during eight years, their statistical uncertainties are below 0.5mas/yr for stars brighter than I=18.5mag. The parallaxes are derived with uncertainties down to 1.6mas. For above 13000 objects parallaxes are derived with significance above 3{sigma}, which allows selecting about 270 white dwarfs (WDs). The search for common proper motion binaries among stars presented was performed resulting in over 500 candidate systems. The most interesting ones are candidate halo main sequence star-WD and WD-WD systems. The application of the catalog to the empirically bound Cepheid instability strip is also discussed.
- ID:
- ivo://CDS.VizieR/J/AcA/52/217
- Title:
- OGLE II. VI photometry of Galactic Bulge
- Short Name:
- J/AcA/52/217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the VI photometric maps of the Galactic bulge. They contain VI photometry and astrometry of about 30 million stars from 49 fields of 0.225 square degree each in the Galactic center region. The data were collected during the second phase of the OGLE microlensing project. We discuss the accuracy of data and present color-magnitude diagrams of selected fields observed by OGLE in the Galactic bulge. The VI maps of the Galactic bulge are accessible electronically for the astronomical community from the OGLE Internet archive
