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Spectroscopic study of blue compact galaxies. I. The spectra
Blue compact galaxies are compact objects that are dominated by intensestar formation. Most of them have dramatically different propertiescompared to the Milky Way and many other nearby galaxies. Using theIRAS, H I data, and optical spectra, we wanted to measure the currentstar formation rates, stellar components, metallicities, and starformation histories and evolution of a large blue compact galaxy sample.We anticipate that our study will be useful as a benchmark for studiesof emission line galaxies at high redshift. In the first paper of thisseries, we describe the selection, spectroscopic observation, datareduction and calibration, and spectrophotometric accuracy of a sampleof 97 luminous blue compact galaxies. We present a spectrophotometricatlas of rest-frame spectra, as well as tables of the recessionvelocities and the signal-to-noise ratios. The recession velocities ofthese galaxies are measured with an accuracy of delta V< 67 kms-1. The average signal-to-noise ratio of sample spectra is ~51. The spectral line strengths, equivalent widths and continuum fluxesare also measured for the same galaxies and will be analyzed in the nextpaper of this series. The atlas and tables of measurements will be madeavailable electronically. Table 3 and Fig. 4 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/389/845
| 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.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| Groups of galaxies. III. Some empirical characteristics.
Not Available
| 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.
| 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.
| Cosmology from a galaxy group catalog. I - Binaries
A new, completely objective group-finding algorithm is described andapplied to the CfA redshift catalog. The binary galaxies are isolatedfor analysis. The assumptions underlying the analysis are (1) that lighttraces mass, (2) that our binary galaxy subsets are representative lighttracers, and (3) that the binary orbits are circular. The primary resultof the work is that the resulting bias-free binary catalogs are afunction of the assumed cosmological model. For virtually any inputvalue of Omega(0) in the range 0.01-5.00, there is a reasonablyconsistent interpretation of the CfA survey such that the specifiedvalue of Omega(0) can be derived from the binary sample obtained underthat interpretation. A secondary result is that the higher the inputvalue of Omega(0), the broader the intrinsic distribution in M/L, andhence the less valid the assumption that light traces mass.
| Photometry of Zwicky compact galaxies
The class of Zwicky compact galaxies (ZCGs) with sharp emission lines isshown by the present aperture UBVRI photometry for 80 ZCGs to have thesame color indices as the Markarian galaxies, as well as the bluecompact dwarf and irregular galaxies in the Virgo cluster; it isaccordingly suggested that they define a family, with differences amongindividuals being primarily due to their different star formationactivity status. The ZCGs without emission lines and with U-V greaterthan 0.4 have color indices similar to those of normal ellipticalgalaxies and, consequently, similar stellar contents.
| A prominent string of galaxies in Bootes - Evidence for a Lagrangian singularity?
An outstanding string of galaxies and of small groups in Bootes has beenfound during a study of bridges between the Coma and the Localsuperclusters. It lies on the boundary of a large void between theHercules and the Local superclusters, has a length of 50 Mpc, is only afew megaparsecs wide, and consists of nonelliptical galaxies. A possibleexplanation by a specific Lagrangian singularity at the formation, theimprint of which has survived in the present galaxy distribution, isproposed.
| A survey of galaxy redshifts. IV - The data
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
| H I observations of blue compact galaxies
Neutral hydrogen observations, in the 21-cm line, of 99 compact galaxiesfrom the lists of Zwicky, Haro, and Markarian were made using the 91-and 305-m telescopes. Most were blue or very blue systems, and 72 weredetected. The overall global properties of these systems are found to bein approximately the same range as normal late-type galaxies. At oneextreme, however, they may extend to types later than Ir I systems.These systems are typically rich in H I gas, and there are indicationsthat they have large H I halos. It is suggested that H I gas infallingfrom such halos may provide the fuel for intermittent bursts of rapidstar formation and may explain the low metallicity found in some bluecompacts.
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