- ID:
- ivo://CDS.VizieR/J/A+AS/138/87
- Title:
- UBVRI photometry of EUV stellar sources
- Short Name:
- J/A+AS/138/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of high-precision UBV(RI)_c_ photometric observations and of spectroscopic radial velocity measurements obtained at the European Southern Observatory for a sample of 51 cool stars detected in the EUV by the ROSAT Wide Field Camera (WFC). Using also recent results from HIPPARCOS, we infer spectral types and investigate the single or binary nature of the sample stars. Optical variability, with periods in the 0.4-13 day range, has been detected for the first time in 15 of these stars.
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- ID:
- ivo://CDS.VizieR/II/277
- Title:
- UBVRI photometry of faint field stars
- Short Name:
- II/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This file, originally prepared for the needs of the Lowell Observatory Near-Earth Object Search (LONEOS), contains a rough working collection of Johnson-Cousins UBVRI photometry assembled mainly from the published literature or from publicly available datasets. The V-R and V-I colors are all on the Cousins system. Most of the stars are fainter than V=10.0; the median magnitude is V=13.9, and significant numbers of stars are listed below 20mag. Besides several large surveys, several hundred small sequences in the regions of variable stars, star clusters, galaxies hosting supernovae, quasars, etc were built by determining coordinates for the sequence stars using the published finder charts. At minimum the data include V magnitudes and at least one ordinary photometric color, most commonly B-V. The data were collected for use in determining approximate photometric zero-points in wide-field imaging, with external accuracy of 0.05 mag or better. Though each dataset was vetted for consistency in magnitude and colors, neither high accuracy nor high precision is guaranteed. Obvious variable stars were omitted, but some unknown variables are inevitably included. In any given field, it is advisable use all the available stars for calibration rather than a single comparison. Several large datasets are included. The Guide Star Photometric Catalogue (GSPC, Lasker et al 1988, Cat. II/143) provides BV sequences near the centers of all the Schmidt sky survey plates. At high latitudes in the southern sky, additional data on the 5-degree Schmidt grid were obtained by Platais et al (1998, Cat. I/277) that extend the GSPC sequences to V=~16. More southern fields were observed by Demers et al (1993A&AS...99..437D and 1993A&AS...99..461D); coordinates for these stars have been determined for the first time. Nearly a thousand high-quality sequences in the northern sky have been observed by Henden, partly published in relation to work on cataclysmic variables (e.g. Cat. J/PASP/107/324) and symbiotic stars (e.g. Cat. J/A+A/143/343). Additional Henden sequences have been adopted from the files cited below at the AAVSO ftp site. These large sequences were trimmed to include only a few stars per magnitude interval, and also to omit crowded stars (no significant companions closer than 15" radius). The star coordinates are mainly from early versions of the GSC or USNO series. As such they are given to 1" precision, and in some cases small systematic errors and (now) proper motion mean their accuracy is in the 1" to 5" range. Thus for automated linkage to CCD frames, some modest search radius should be adopted to match with the catalogue. Because the file was originally intended for private use, bibliographic references were not included except in a very few instances. Usually it is straightforward to recover the source paper by inspection of the SIMBAD bibliography for specific objects. Problematic cases can be directed to the compiler (Brian Skiff).
- ID:
- ivo://CDS.VizieR/J/AJ/119/2571
- Title:
- UBVRI photometry of HDF QSOs and galaxies
- Short Name:
- J/AJ/119/2571
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged a 45'x45' area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to the limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2, respectively. The principal goals of the survey are to identify quasi-stellar objects (QSOs) and to map structure traced by luminous galaxies and QSO absorption line systems in a wide volume containing the HDF. The area surveyed is 400 times as large as that of the HDF, and 40 times as large as that of the HDF Flanking Fields. We have selected QSO candidates from color space and identified four QSOs and two narrow emission line galaxies not yet discovered, bringing the total number of known QSOs in the area to 19.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2971
- Title:
- UBVRI photometry of 131 Herbig Ae/Be
- Short Name:
- J/AJ/126/2971
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias Survey (Gregorio-Hete et al., 1992AJ....103..549G; Torres et al., 1995AJ....109.2146T and 1999, Special Publ. 10, Rio de Janeiro: Obs. Nac.), together with 19 previously known candidates and four objects selected from the IRAS Faint Source Catalog (<II/156>). These 131 stars were observed with low- and/or medium-resolution spectroscopy, and we complement these data with high-resolution spectra of 39 stars.
- ID:
- ivo://CDS.VizieR/J/AJ/144/41
- Title:
- UBVRI photometry of M33 star clusters. I.
- Short Name:
- J/AJ/144/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRI photometry for 392 star clusters and candidates in the field of M33, which are selected from the most recent star cluster catalog. In this catalog, the authors listed star clusters' parameters such as cluster positions, magnitudes, colors in the UBVRIJHK_s_filters, and so on. However, a large fraction of objects in this catalog do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 0.8deg^2^ along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements. Positions (right ascension and declination) for some clusters are corrected here. Combined with previous literature, ours constitute a large sample of M33 star clusters. Based on this cluster sample, we present some statistical results: none of the youngest M33 clusters (~10^7^yr) have masses approaching 10^5^M_{sun}_; roughly half the star clusters are consistent with the 10^4^-10^5^M_{sun}_ mass models; the continuous distribution of star clusters along the model line indicates that M33 star clusters have been formed continuously from the epoch of the first star cluster formation until recent times; and there are ~50 star clusters which are overlapped with the Galactic globular clusters on the color-color diagram, and these clusters are old globular cluster candidates in M33.
- ID:
- ivo://CDS.VizieR/J/AJ/145/88
- Title:
- UBVRI photometry of M33 star clusters. II.
- Short Name:
- J/AJ/145/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper of our series. In this paper, we present UBVRI photometry for 234 star clusters in the field of M33. For most of these star clusters, there is photometry in only two bands in previous studies. The photometry of these star clusters is performed using archival images from the Local Group Galaxies Survey, which covers 0.8deg^2^ along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements, and in particular that our photometry is in good agreement with that of Zloczewski & Kaluzny. Combined with star cluster photometry in previous studies, we present some results: none of the M33 youngest clusters (~10^7^yr) have masses approaching 10^5^M_{sun}_, and comparisons with models of simple stellar populations suggest a large range of ages for M33 star clusters and some as old as the Galactic globular clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/404/927
- Title:
- UBVRI photometry of NGC 2422
- Short Name:
- J/A+A/404/927
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRI photometry of the open cluster NGC 2422 (age~10^8^yr) down to a limiting magnitude V=~19. These data are used to derive the Luminosity and Mass Functions and to study the cluster spatial distribution. By considering the color-magnitude diagram data and adopting a representative cluster main sequence, we obtained a list of candidate cluster members based on a photometric criterion.
- ID:
- ivo://CDS.VizieR/J/A+A/333/471
- Title:
- UBVRI photometry of NGC 1750 and NGC 1758
- Short Name:
- J/A+A/333/471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The existence and relationship of the possible clusters NGC 1746, NGC 1750 and NGC 1758 has been a matter of discussion during the last decades. This star field is close to the galactic anticenter and lies in the direction of the Taurus dark cloud complex. As part of a comprehensive astrometric and photometric analysis of this zone, we present a brief historical introduction together with deep UBVRI-CCD photometry of the area. The presence of at least one cluster can be deduced from these data. This object has a position and apparent size compatible with those previously quoted for NGC 1750 and NGC 1758. It is not possible to distinguish the single or double nature of the cluster on the sole basis of our photometry and the spatial distribution of the stars. No photometric evidence was found for NGC 1746.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/804
- Title:
- UBVRI photometry of NGC559 stars
- Short Name:
- J/MNRAS/437/804
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRI photometry of stars in the field of the intermediate-age open cluster NGC 559. By determining the stellar membership probabilities derived through a photometric and kinematic study of the cluster, we identify the 22 most probable cluster members. These are used to obtain robust cluster parameters. The mean proper motion of the cluster is {mu}_x_=-3.29+/-0.35, {mu}_y_=-1.24+/-0.28mas/yr. The radial distribution of the stellar surface density gives a cluster radius of 4.5+/-0.2arcmin (3.2+/-0.2pc). By fitting solar metallicity stellar isochrones to the colour-colour and colour-magnitude diagrams, we find a uniform cluster reddening of E(B-V)=0.82+/-0.02. The cluster has an age of 224+/-25Myr and is at a distance of 2.43+/-0.23kpc. From the optical and near-infrared two-colour diagrams, we obtain colour excesses in the direction of the cluster E(V-K)=2.14+/-0.02, E(J-K)=0.37+/-0.01 and E(B-V)=0.76+/-0.04. A total-to-selective extinction of R_V_=3.5+/-0.1 is found in the direction of the cluster which is marginally higher than the normal value. We derive the luminosity function and the mass function for the cluster main sequence. The mass function slope is found to be -2.12+/-0.31. We find evidence of mass segregation in this dynamically relaxed cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/98/1693
- Title:
- UBVRI photometry of NLTT stars
- Short Name:
- J/AJ/98/1693
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI photometry is presented for a sample of 1656 southern stars, including 1211, that were previously not measured, drawn from the NLTT (Luyten, 1979; catalogue I/98) proper-motion catalog; the catalog is shown to be a rich source of subdwarfs. The normalized UV excess, d(U-B)0.6, photometric parallax, and interstellar reddening are calculated for each star when possible. Residuals between the photometry and the magnitudes published in the NLTT catalog indicate that the latter have a large scatter (~0.6mag) and therefore the values tabulated in the NLTT catalog must be regarded as approximate only. The erratum (Astron. J. 99, 1336) which deals with position angles of proper motions (pmPA) has been taken into account.