תוכן
תמונות
הוסף תמונה שלך
DSS Images Other Images
מאמרים קשורים
FLASH redshift survey - I. Observations and catalogue
The FLAIR Shapley-Hydra (FLASH) redshift survey catalogue consists of4613 galaxies brighter than bJ= 16.7 (corrected for Galacticextinction) over a 700-deg2 region of sky in the generaldirection of the Local Group motion. The survey region is a70°× 10° strip spanning the sky from the ShapleySupercluster to the Hydra cluster, and contains 3141 galaxies withmeasured redshifts. Designed to explore the effect of the galaxyconcentrations in this direction (in particular the Supergalactic planeand the Shapley Supercluster) upon the Local Group motion, the 68 percent completeness allows us to sample the large-scale structure betterthan similar sparsely-sampled surveys. The survey region does notoverlap with the areas covered by ongoing wide-angle (Sloan or 2dF)complete redshift surveys. In this paper, the first in a series, wedescribe the observation and data reduction procedures, the analysis forthe redshift errors and survey completeness, and present the surveydata.
| Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
In this paper we describe the Nearby Optical Galaxy (NOG) sample, whichis a complete, distance-limited (cz<=6000 km s-1) andmagnitude-limited (B<=14) sample of ~7000 optical galaxies. Thesample covers 2/3 (8.27 sr) of the sky (|b|>20deg) andappears to have a good completeness in redshift (97%). We select thesample on the basis of homogenized corrected total blue magnitudes inorder to minimize systematic effects in galaxy sampling. We identify thegroups in this sample by means of both the hierarchical and thepercolation ``friends-of-friends'' methods. The resulting catalogs ofloose groups appear to be similar and are among the largest catalogs ofgroups currently available. Most of the NOG galaxies (~60%) are found tobe members of galaxy pairs (~580 pairs for a total of ~15% of objects)or groups with at least three members (~500 groups for a total of ~45%of objects). About 40% of galaxies are left ungrouped (field galaxies).We illustrate the main features of the NOG galaxy distribution. Comparedto previous optical and IRAS galaxy samples, the NOG provides a densersampling of the galaxy distribution in the nearby universe. Given itslarge sky coverage, the identification of groups, and its high-densitysampling, the NOG is suited to the analysis of the galaxy density fieldof the nearby universe, especially on small scales.
| Hα objective prism survey of Abell 1060
As part of a continuing study of the effect of cluster environment onthe star formation properties of galaxies, we have undertaken anHα objective prism survey of the nearby cluster, Abell 1060. Wedetect 33 galaxies in emission, 24 of which are cluster members. Wepresent new radial velocity measurements and Hα + [N Ii]equivalent widths and fluxes for a number of these galaxies. Wedistinguish between galaxies with diffuse and compact emission, thelatter having been associated in previous work with a disturbedmorphology of the galaxy and most likely resulting from tidally-inducedstar formation from galaxy-galaxy or cluster-galaxy interactions. Thefraction of cluster spirals in Abell 1060 detected with compact emissionagrees with the expected fraction for a cluster of its richness, asderived from results of a previous survey of 8 clusters. Some of thedetected cluster early-type spirals exhibit anomalously high globalHα equivalent widths, as compared to galaxies of similar type inthe field.
| Total magnitude, radius, colour indices, colour gradients and photometric type of galaxies
We present a catalogue of aperture photometry of galaxies, in UBVRI,assembled from three different origins: (i) an update of the catalogueof Buta et al. (1995) (ii) published photometric profiles and (iii)aperture photometry performed on CCD images. We explored different setsof growth curves to fit these data: (i) The Sersic law, (ii) The net ofgrowth curves used for the preparation of the RC3 and (iii) A linearinterpolation between the de Vaucouleurs (r(1/4) ) and exponential laws.Finally we adopted the latter solution. Fitting these growth curves, wederive (1) the total magnitude, (2) the effective radius, (3) the colourindices and (4) gradients and (5) the photometric type of 5169 galaxies.The photometric type is defined to statistically match the revisedmorphologic type and parametrizes the shape of the growth curve. It iscoded from -9, for very concentrated galaxies, to +10, for diffusegalaxies. Based in part on observations collected at the Haute-ProvenceObservatory.
| Parameters of 2447 Southern Spiral Galaxies for Use in the Tully-Fisher Relation
I-band luminosities, rotational velocities, and redshifts of 1092 spiralgalaxies have been measured by CCD photometry and Hα spectroscopyusing the 1 m and 2.3 m telescopes at Siding Spring Observatory,respectively. The results are tabulated. Luminosity profiles andHα rotation curves are given for the galaxies. When these resultsare combined with similar data for 1355 spiral galaxies publishedpreviously (Mathewson, Ford, & Buchhorn, hereafter Paper I), itprovides a large, uniform, and unique data set with which to measure,via the Tully-Fisher relation, the peculiar velocities of galaxies inthe local universe to a distance of 11,000 km s^-1^ (Mathewson &Ford). Taking advantage of the opportunity for publishing this data inmachine-readable form, in the CD-ROM, we have also included similar datafor the 1355 galaxies in Paper I.
| Surface photometry of the Hydra I cluster of galaxies. I - Photometric data
Surface photometry was made for 137 galaxies on a UK Schmidt plate whosecenter is located at the center of the Hydra I (A1060 ) cluster ofgalaxies. For 133 of the 137 galaxies, such photometric parameters astotal magnitude, equivalent radius, concentration indices, and meansurface brightness were obtained. The total magnitudes were comparedwith those in the literature to check the accuracy of the present data.The estimated accuracy in the total magnitudes is about 0.1 mag at mostfor majority of the galaxies.
| Infrared and optical photometry of galaxies in four clusters and of a sample of early-type galaxies
JHKL' multi-aperture infrared photoelectric photometry is presented herefor a sample of galaxies belonging to the Virgo and ABCG 539 clusters.Optical and infrared photometry are also given for members of the Hydracluster and of the southern extension of the Perseus supercluster. Wealso give optical photoelectric photometry of 19 early-type (ellipticaland S0) field galaxies.
| General study of group membership. II - Determination of nearby groups
We present a whole sky catalog of nearby groups of galaxies taken fromthe Lyon-Meudon Extragalactic Database. From the 78,000 objects in thedatabase, we extracted a sample of 6392 galaxies, complete up to thelimiting apparent magnitude B0 = 14.0. Moreover, in order to considersolely the galaxies of the local universe, all the selected galaxieshave a known recession velocity smaller than 5500 km/s. Two methods wereused in group construction: a Huchra-Geller (1982) derived percolationmethod and a Tully (1980) derived hierarchical method. Each method gaveus one catalog. These were then compared and synthesized to obtain asingle catalog containing the most reliable groups. There are 485 groupsof a least three members in the final catalog.
| The Hydra I cluster of galaxies. V - A catalogue of galaxies in the cluster area
The available information for 581 galaxies in the area of the Hydra I (= Abell 1060) cluster is compiled into a catalog. Positions, magnitudes,diameters, position angles, radial velocities, and morphological typesare given. A first determination of the luminosity function of Hydra Iis attempted. An assessment of the photometric errors in the isophotalmagnitudes is included.
| Southern Galaxy Catalogue.
Not Available
| The Hydra I cluster of galaxies. II - First results from H I observations
The number of known redshifts in the area of the Hydra I cluster hasbeen raised to 96, through the detection of 17 galaxies in the course ofH I 21-cm line observations of 42 galaxies in this field. Evidence isalso found for an increase of the H I deficiency factor radially inwardsto the center of the cluster. The cluster's distance modulus, relativeto the Virgo cluster from the blue magnitude Tully-Fisher relation is inagreement with other determinations and with the value that is based onthe ratio of cluster redshifts; a constraint to the infall velocity ofthe Local Group toward the Virgo cluster is therefore given to values ofless than 350 km/sec.
|
הכנס מאמר חדש
לינקים קשורים
הכנס לינק חדש
משמש של הקבוצה הבאה
|
תצפית ומידע אסטרומטרי
קטלוגים וכינוים:
|
