Tartalom
Képek
Kép feltöltése
DSS Images Other Images
Kapcsolódó cikkek
The UZC-SSRS2 Group Catalog
We apply a friends-of-friends algorithm to the combined Updated ZwickyCatalog and Southern Sky Redshift Survey to construct a catalog of 1168groups of galaxies; 411 of these groups have five or more members withinthe redshift survey. The group catalog covers 4.69 sr, and all groupsexceed the number density contrast threshold, δρ/ρ=80. Wedemonstrate that the groups catalog is homogeneous across the twounderlying redshift surveys; the catalog of groups and their membersthus provides a basis for other statistical studies of the large-scaledistribution of groups and their physical properties. The medianphysical properties of the groups are similar to those for groupsderived from independent surveys, including the ESO Key Programme andthe Las Campanas Redshift Survey. We include tables of groups and theirmembers.
| Morphological analysis of open clusters' propertiesI. Properties' estimations
A sample of 160 UBVCCD observations of open star clusters near thegalactic plane has been studied, and a catalogue of their propertiesobtained. The main photometrical properties have been re-estimated selfconsistently and the results have been compared with those of Lynga[Lynga, G., 1987. Catalog of Open Cluster Data, 5th Edition, StellarData Centers, Observatoire de Strasbourg, France].
| Dense Cores of Dark Clouds. XII. 13CO and C18O in Lupus, Corona Australis, Vela, and Scorpius
More than 110 dense condensations of the dark clouds in Lupus, CoronaAustralis, Norma, Vela, and Scorpius were observed in the13CO and C18O (J=1-0) transitions. Thecondensations of dark clouds with high star formation activity like theOphiuchus, Taurus, and Cepheus have average C18O andH2 column densities of 1.8x1015 and1.1x1022 cm-2. If we take the average size of thecondensations to be 0.2 pc, a condensation must have averageH2 volumetric densities >=2x104 cm-3in order to be a good candidate to form stars. The four Lupus filamentshave similar radial velocities and velocity dispersions, suggesting thatthey originated from the same parental cloud. Among these filaments,Lupus 1 is unique in having recent star formation activity, despite thehigh number of T Tauri stars observed toward the others. Lupus 1 alsoshows a complex velocity gradient along its main axis. The distributionof radial velocities of the condensations observed toward Scorpius arein good agreement with the hypothesis that they are in a region withexpansion velocity smaller than or equal to 18 km s-1. TheCorona Australis cloud has velocity gradients ranging from -0.5 kms-1 pc-1 at one extreme to 0.1 km s-1pc-1 at the other.
| Search for Low-Instability Strip Variables in the Young Open Cluster NGC 2516
In this paper we revise and complete the photometric survey of theinstability strip of the southern open cluster NGC 2516 published byAntonello & Mantegazza. No variable stars with amplitudes largerthan 0.02 mag were found. However, by means of an accurate analysisbased on a new statistical method, two groups of small-amplitudevariables have been disentangled: one with periods of less than 0.25days (probably delta Scuti stars) and one with periods of greater than0.025 days. The position in the H-R diagram and the apparent timescalemay suggest that the stars of the second group belong to a recentlydiscovered new class of variables, named gamma Dor variables. Theycertainly deserve further study. We also present a comparison betweenthe results of the photometric survey and the available pointed ROSATobservations of this cluster.
| An image database. II. Catalogue between δ=-30deg and δ=70deg.
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
| The CfA Redshift Survey: Data for the NGP +36 Zone
We have assembled redshifts for a complete sample of 719 galaxies withm_zw_ <= 15.5 in the declination range 32.5^deg^ <= δ <=38.5^deg^ and right ascension range 8^h^ <= α <= 17^h^. Wehave determined morphological types for all galaxies in the magnitudelimited sample by direct inspection of the POSS-O plates. 576 of theredshifts are measurements from Mount Hopkins, and 405 are newredshifts. We also include new redshifts for 77 fainter galaxies in thesame strip.
| Velocity measurements in the Coma filament of galaxies
58 new velocity measurements of galaxies located in the Coma filamentcarried out with the 2.5-m Issac Newton telescope at La Palma arepresented. These optical observations complete a sample of 21-cm lineobservations in the same region up to the 15.0th magnitude.
| Cool Carbon Stars in Open Clusters (abstract)
Not Available
|
Új cikk hozzáadása
Kapcsolódó hivatkozások
- - (nincs kapcsolódó hivatkozás) -
Új link hozzáadása
Besorolás csoportokba:
|
Pozíciós és asztrometriai adatok
Katalógusok és elnevezések:
|
