- ID:
- ivo://CDS.VizieR/I/206
- Title:
- Bright Stars Supplement to PPM
- Short Name:
- I/206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A number of bright stars is missing from the PPM Star Catalogue, both on the northern <I/146> and on the southern <I/193> hemisphere. The Bright Stars Supplement described here makes PPM complete down to V=7.5 mag. For this purpose it lists all missing stars brighter than V=7.6 mag that we could find in published star lists. Their total number is 275. Only 2 of them are brighter than V=3.5. This replaces the December 1992 edition (catalogue I/194) of the Bright Stars Supplement which inadvertently contained 46 duplicates of stars already contained in the main parts of PPM.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/I/99
- Title:
- Brorfelde Meridian Catalogues 1964-1976
- Short Name:
- I/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains positions and magnitudes for 1577 stars with visual magnitudes brighter than 11.0. The observations were made with the 7-inch transit circle at the Copenhagen University Observatory from July 1981 to May 1982. The positions are reduced to the FK4 system for each night and over the whole meridian. The mean errors of the catalog entries are: in right ascension 0.006 seconds/cos(declination); in declination, 0.10"; and in magnitude, 0.06mag. The catalog contains 425 FK4 stars used for the adjustment to the FK4; 167 stars from the AGK3 zones +88deg. and +89deg.; 115 stars from the zone around the North Galactic Pole; stars from several PZT zones; some faint GC stars; reference stars for radio fields; and a few stars from earlier Brorfelde programs. The internal errors of a single observation are for right ascension, 0.0138 seconds/cos(delta), for declination, 0.216", and for the magnitude, 0.132 mag.
- ID:
- ivo://CDS.VizieR/I/31
- Title:
- Bucharest KSZ Faint Stars, -11 to +11, 1950.0
- Short Name:
- I/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the results of the differential observations of 3939 stars made with the Transit Circle of the Bucharest Observatory, from 1955 July 1 to 1962 June 16. The positions were observed simultaneously with the Catalog of the Southern Reference Star program. 105 stars were selected to be near extragalactic nebulae; the remaining 3852 stars were from the KSZ list. The positions are on the FK3R system for the equinox, 1950.0. Mean errors are 0.029s and 0.49" in right ascension and declination, respectively. The catalog contains for each star, in addition to the positions: the BD number, magnitude, spectral type, individual mean errors, epoch of the observations, number of observations in each coordinate, number of the star in the list of areas near extragalactic nebulae, and notes.
- ID:
- ivo://CDS.VizieR/J/AJ/107/230
- Title:
- BVRI CCD photometry of NGC 1904
- Short Name:
- J/AJ/107/230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI photometry of three overlapping fields in the globular cluster NGC 1904 (M79), observed with a CCD camera and the 2.2m Max-Planck-Institute telescope at ESO/La Silla. We critically compare our photometry using the INVENTORY data reduction code with results derived by other investigators using different codes. These comparisons convince us that all modern codes give results reliable to at least +/-0.3mag at all levels, as long as the fields are not overly crowded. Specifically, our results for NGC 1904 (M79) are as follows: V(TO)=19.60+/-0.10 (estimated external error), with turnoff colors at B-V=0.40, V-R=0.27, V-I=0.57, and B-I=0.97, all with estimated external errors of +/-0.06. By fitting the four resulting ridge lines to the theoretical isochrones of VandenBerg & Bell [ApJS, 58, 561 (1985)] interpolated to [Fe/H]=-1.60, Y=0.20, and [O/Fe]=0.00, we derive an average value for the age of 16Gyr, where we have adopted E(B-V)=0.01.
- ID:
- ivo://CDS.VizieR/J/A+A/416/1037
- Title:
- BVRIK Photometry for the field of 4U 0142+61
- Short Name:
- J/A+A/416/1037
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new optical and infrared observations of the counterpart to the Anomalous X-ray Pulsar (AXP) 4U 0142+61 taken with the Keck I telescope. The counterpart is found to be variable in the infrared. This contrasts with our optical observations, which do not show any evidence for variability. Apart from the variability the AXP shows a remarkable spectral energy distribution. In particular, we find a sudden drop in flux going from V to B, presumably due to a spectral feature. We compare our results to those obtained for the two other securely identified AXP counterparts, to 1E 2259+586 and 1E 1048.1-5937. 4U 0142+61 is very similar to the former source in its X-ray timing and spectral properties, and we find that this similarity extends to the quiescent infrared to X-ray flux ratio. For 1E 1048.1-5937, which has different X-ray properties, the situation is less clear: in one observation, the infrared to X-ray flux ratio was much larger, but another observation gave an upper limit which is consistent with that observed for 4U 0142+61. Assuming the quiescent ratios are all similar, we estimate the optical and infrared brightnesses for the three AXPs that remain to be identified as well as for the four Soft Gamma-ray Repeaters. We also discuss briefly how the observed optical and infrared emission might arise, in particular in the context of the magnetar model.
- ID:
- ivo://CDS.VizieR/J/AJ/110/212
- Title:
- BVR photometry of stars in NGC 2366
- Short Name:
- J/AJ/110/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar content of the Im galaxy NGC 2366 is discussed on the basis of CCD BVR photometry. The three brightest blue and red stars have been used to estimate its distance, obtaining a value of 2.9pc. The spatial distribution of the young stellar population is discussed in the light of the integrated color indices and the color-magnitude diagrams of different zones of the galaxy. A generalized star formation burst seems to have taken place about 50Myr ago. The youngest stars are preferentially formed in the South-West part of the bar, where the giant H II complex NGC 2363 is located, being younger and bluer. The bar seems to play a role favoring star formation in one of its extremes. Self-propagation however, does not seem to be triggering star formation at large scale. A small region, populated by very young stars has also been found at the East of the galaxy.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/269
- Title:
- Calern Observatory absolute declinations
- Short Name:
- J/A+AS/137/269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A regular observational programme with a photoelectric astrolabe have been performed at ``Observatoire du Calern" (Observatoire de la Cote d'Azur, OCA, {phi}=+43{deg}44'55.011"; {lambda}=-0^h^27^m^42.44^s^, Calern, Caussols, France) for the last twenty years. It has been almost fully automatized between 1984 and 1987. Since 1988 the photoelectric astrolabe was used without any modification. In addition to determining the daily orientation of the local vertical, the yearly analysis of the residuals permits to derive corrections to the used star catalogue Vigouroux et al. (1992A&AS...96..477V). A global reduction method was applied for the ASPHO observations. The new form of the equations Martin & Leister (1997A&AS..126..169M) give us the possibility of using the entire set of the observing program using data taken at two zenith distances (30{deg} and 45{deg}). The program contains about 41648 stars' transits of 269 different stars taken at ``Observatoire du Calern" (OCA). The reduction was based on the HIPPARCOS system. We discuss the possibility of computing absolute declinations through stars belonging simultaneously to the 30{deg} and 45{deg} zenith distances programmes. The absolute declination corrections were determined for 185 stars with precision of 0.027" and the value of the determined equator correction is -0.018"+/-0.005". The instrumental effects were also determined. The mean epoch is 1995.29.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A177
- Title:
- Candidate Cluster Members with Deep learning
- Short Name:
- J/A+A/643/A177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The next generation of extensive and data-intensive surveys are bound to produce a vast amount of data, which can be efficiently dealt with using machine-learning and deep-learning methods to explore possible correlations within the multi-dimensional parameter space. We explore the classification capabilities of convolution neural networks (CNNs) to identify galaxy cluster members (CLMs) by using Hubble Space Telescope (HST) images of fifteen galaxy clusters at redshift 0.19<~z<~0.60, observed as part of the CLASH and Hubble Frontier Field programmes. We used extensive spectroscopic information, based on the CLASH-VLT VIMOS programme combined with MUSE observations, to define the knowledge base. We performed various tests to quantify how well CNNs can identify cluster members on ht basis of imaging information only. Furthermore, we investigated the CNN capability to predict source memberships outside the training coverage, in particular, by identifying CLMs at the faint end of the magnitude distributions. We find that the CNNs achieve a purity-completeness rate >~90%, demonstrating stable behaviour across the luminosity and colour of cluster galaxies, along with a remarkable generalisation capability with respect to cluster redshifts. We concluded that if extensive spectroscopic information is available as a training base, the proposed approach is a valid alternative to catalogue-based methods because it has the advantage of avoiding photometric measurements, which are particularly challenging and time-consuming in crowded cluster cores. As a byproduct, we identified 372 photometric cluster members, with mag(F814)<25, to complete the sample of 812 spectroscopic members in four galaxy clusters RX J2248-4431, MACS J0416-2403, MACS J1206-0847 and MACS J1149+2223. When this technique is applied to the data that are expected to become available from forthcoming surveys, it will be an efficient tool for a variety of studies requiring CLM selection, such as galaxy number densities, luminosity functions, and lensing mass reconstruction.
- ID:
- ivo://CDS.VizieR/J/ApJS/67/461
- Title:
- Candidate field horizontal-branch stars catalog
- Short Name:
- J/ApJS/67/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Coordinates and brightness estimates are presented for 4408 candidate field horizontal-branch stars selected using an objective-prism, interference-filter survey technique. The candidates lie primarily in the southern Galactic hemisphere, and are distributed in color over the range B-V from -0.2 to 0.40. Previous spectroscopic observation of a subset of these candidates indicates that roughly 85 percent of the catalog objects are bona fide members of the field blue horizontal branch. The remaining candidates include, in order of frequency, stars with main-sequence gravity which are likely to be a mix of metal-deficient turnoff stars and field blue stragglers, metallic line (Am) stars, A stars of near-solar metallicity, and high-luminosity or binary stars.
- ID:
- ivo://CDS.VizieR/J/other/Sci/292.698
- Title:
- Candidate halo dark matter
- Short Name:
- J/other/Sci/292.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Milky Way galaxy contains a large, spherical component which is believed to harbor a substantial amount of unseen matter. Recent observations indirectly suggest that as much as half of this "dark matter" may be in the form of old, very cool white dwarfs, the remnants of an ancient population of stars as old as the galaxy itself. We conducted a survey to find faint, cool white dwarfs with large space velocities, indicative of their membership in the galaxy's spherical halo component. The survey reveals a substantial, directly observed population of old white dwarfs, too faint to be seen in previous surveys. This newly discovered population accounts for at least 2 percent of the halo dark matter. It provides a natural explanation for the indirect observations, and represents a direct detection of galactic halo dark matter.
