- ID:
- ivo://CDS.VizieR/J/MNRAS/502/6080
- Title:
- New members of Cygnus OB2 from Gaia DR2
- Short Name:
- J/MNRAS/502/6080
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Due to the high quality of Gaia DR2 stellar parallaxes and proper motions, we can study the Cygnus OB2 region up to G=17.5mag in circular region centred at (l,b)=(79.8{deg},+0.8{deg}) of radius 1{deg}. We detect four over-densities in the Vector Point Diagram. We apply a parametric model of the proper motion distribution and determine their mean proper motions, identify their members and estimate their distances by analyzing the parallaxes of the most probable members. We confirm that one of these regions is Cygnus OB2, whose mean proper motion is (pmRA*cosDE,pmDE)=(-2.71+/-0.02,-4.24+/-0.02)mas/yr. We identify 2767 astrometric members at an estimated distance of 1683 {+/-} 5 pc. A detailed comparison of these members with 333 photometric and spectroscopic Cygnus OB2 members shows that 33 stars of the last group are not members, 16 of them are O-B stars. 300 members in common lead to estimate a distance to the association of 1669+/-6pc. One of the remaining over-densities is the open cluster UCB585 for which we find eight more members, located at ~1460pc. The other two groups count 179 and 188 proper motion members which are distributed throughout the region and situated at a distance of ~1280 pc. The estimated distances of these four groups suggest the existence of different substructures in the Cygnus OB2 region along the line of sight.
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- ID:
- ivo://CDS.VizieR/J/AcA/63/135
- Title:
- New OGLEIII dwarf novae in Galactic disk
- Short Name:
- J/AcA/63/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of forty erupting cataclysmic variable stars in the OGLE-III Galactic disk fields: seventeen objects of U Gem type, four of Z Cam type, and nineteen stars showing outbursts and superoutbursts typical for SU UMa type dwarf novae. In the case of five stars we were able to estimate their supercycle lengths. The obtained lengths are in the range of 20-90 d, generally between the typical SU UMa type variables and a few objects classified as the ER UMa type variables. Since there is no significant difference between the two types but a higher mass-transfer rate resulting in more frequent outbursts and superoutbursts in the ER UMa type stars, we propose to discard this type as a separate class of variables. We note that in one of the SU UMa type stars, OGLE-GD-DN-039, we found a negative supercycle period change, in contrast to other active systems of this type. Two of the new OGLE objects showed long-duration WZ Sge-like superoutbursts followed by a sequence of echo outbursts. All stars reported in this paper are part of the OGLE-III Catalog of Variable Stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/331/45
- Title:
- New periodic variables
- Short Name:
- J/MNRAS/331/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two selection statistics are used to extract new candidate periodic variables from the epoch photometry of the Hipparcos catalogue. The primary selection criterion is a signal-to-noise ratio. The dependence of this statistic on the number of observations is calibrated using about 30000 randomly permuted Hipparcos data sets. A significance level of 0.1 per cent is used to extract a first batch of candidate variables. The second criterion requires that the optimal frequency be unaffected if the data are de-trended by low-order polynomials. We find 2675 new candidate periodic variables, of which the majority (2082) are from the Hipparcos unsolved variables. Potential problems with the interpretation of the data (e.g. aliasing) are discussed.
- ID:
- ivo://CDS.VizieR/J/A+AS/135/29
- Title:
- New periods of variable stars in Cygnus
- Short Name:
- J/A+AS/135/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Table2 summarizes the photographic magnitudes obtained over 24 years at the Skalnate Pleso (1979-1993) and Asiago (1969-1988) observatories for 17 variable stars of different types: Miras (7), Semi-regular (4), Cepheids (3), RR Lyr (2), Eclipsing binary (1). The cross-reference between star No., designation according to Margoni and Stagni (1984A&AS...56...87M) and catalogue one (provided it has already been adopted for a given star) according to the GCVS (See Cat. <II/214>) and IBVS (Kholopov al., 1987, See Cat. <II/195>) is given in Table3 as well as the equatorial coordinates for the epoch 1950.0 for each star, which is compatible with the GCVS. In this table are shown the basic characteristics of the observational material for each star: the number of data points and interval of magnitudes obtained at the Asiago Observatory (A) and Skalnate Pleso Observatory (SP) respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/353/958
- Title:
- New proper motions in 0<RA<7h, -63<DE<-32{deg}
- Short Name:
- J/A+A/353/958
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of about 100 new high-proper motion stars in the region between 0^h^ and 7^h^ in right ascension and -63{deg} and -32{deg} in declination, with proper motions between 0.3 and 1.0arcsec/yr. In addition we have obtained improved coordinates and photographic photometry for another about 100 already known high-proper motion stars in the same region. In this study we have made use of APM measurements of UKST survey plates in 40 survey fields. Using all available information (position, proper motion, photographic R magnitude and B_J_-R colour index), we draw some preliminary conclusions on the nature of the new high-proper motion stars, particularly of extreme cases.
- ID:
- ivo://CDS.VizieR/J/ApJ/670/92
- Title:
- New sample of low-mass black holes in AGN
- Short Name:
- J/ApJ/670/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan Digital Sky Survey all broad-line active galaxies with masses <2x10^6^M_{sun}_ BHs in this mass regime provide unique tests of the relationship between BHs and galaxies, since their late-type galaxy hosts do not necessarily contain classical bulges. Furthermore, they provide observational analogs of primordial seed BHs and are expected, when merging, to provide strong gravitational signals for future detectors such as LISA. From our preliminary sample of 19, we have increased the total sample by an order of magnitude to 174, as well as an additional 55 (less secure) candidates.
- ID:
- ivo://CDS.VizieR/J/PAZh/34/21
- Title:
- New spectral types for Tycho2 stars
- Short Name:
- J/PAZh/34/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the spectroscopic and trigonometric parallaxes of common stars from the Tycho-2 Spectral Type and Hipparcos Catalogues. This comparison has revealed that the distance estimations for the overwhelming majority of stars by both methods yield very similar results. However, there is a small fraction of stars for which the distance estimates differences.
- ID:
- ivo://CDS.VizieR/J/A+A/444/831
- Title:
- New star clusters in M33
- Short Name:
- J/A+A/444/831
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we present the detection of 33 star clusters and 51 candidates in one field of the near by galaxy M 33. This study is based on WFC/ACS images available from the HST archive. Thanks to the high resolving power, we were able to confirm that two candidates previously indicated by Christian & Schommer (1982ApJS...49..405C) are indeed star clusters. We list the main properties for the star clusters (and candidates), along with some peculiar objects, such as background galaxies and possible HII regions.
- ID:
- ivo://CDS.VizieR/J/A+A/373/899
- Title:
- New variables in M22 globular cluster
- Short Name:
- J/A+A/373/899
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1 contains equatorial coordinates for 36 newly identified variables from the central field of the globular cluster M22. File table2 contains basic photometric data for SX Phe stars reported in the paper. File table3 contains magnitudes and colors for selected sample of new variables. Files table4-39 contain V-band time-series photometry for 36 newly identified variables from the central field of the globular cluster M22. Individual finding charts for new variables are in fig directory; each chart is 33arcsec on a side with north up and east to the left.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/507
- Title:
- New variables in Sagittarius
- Short Name:
- J/A+AS/123/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the coordinates and identification charts of the variables discovered in the other parts of the surveyed region, see references in the publication. A compilation of all the (~4000) variables discovered in the entire 100 square-degree surveyed region in the course of this programme, is in preparation and will be available at CDS in electronic form.
