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E+A Galaxies in the Near-Infrared: Broadband Photometry
This paper presents near-IR photometry of a selected sample of southernhemisphere E+A galaxies. The sample includes 50 galaxies from nearby(z~0.05) and distant (z~0.3) clusters, as well as E+A galaxies from thefield (z~0.1). Observations include 13 normal early-type galaxies fromthe field and from clusters to be compared with the E+A sample. Thephotometry includes J, H, and Ks apparent magnitudes andcolors. Observed colors are obtained from the apparent total magnitudesand compared with those of the GISSEL96 spectrophotometric models ofgalaxy evolution. There is an overall agreement between integratedcolors of models and observed ones, for both the E+A galaxies located inclusters and those in the field, at z<~0.1. However, largedifferences between colors predicted from models and those observed inE+A galaxies located in clusters at z~0.3 are found. We also computerest-frame colors for all the galaxies using two different sets ofK-corrections and obtain average colors for all the samples. This workinvestigates systematic properties of the E+A sample as a function ofits environment. Results seem to indicate that cluster E+A galaxies (atlow redshift) are bluer than field E+A galaxies at z~0.1. Even thisconclusion does not depend on whether we use comoving or rest-framecolors or on the models used to obtain rest-frame colors; the differenceis not significant enough, considering color dispersions between thesamples. If the differences are real, they could imply a differentstellar content for the E+A galaxies located in the field compared withthose located in the cluster E+A galaxies.
| Galaxy coordinates. II. Accurate equatorial coordinates for 17298 galaxies
Using images of the Digitized Sky Survey we measured coodinates for17298 galaxies having poorly defined coordinates. As a control, wemeasured with the same method 1522 galaxies having accurate coordinates.The comparison with our own measurements shows that the accuracy of themethod is about 6 arcsec on each axis (RA and DEC).
| The Southern Sky Redshift Survey
We report redshifts, magnitudes, and morphological classifications for5369 galaxies with m_B <= 15.5 and for 57 galaxies fainter than thislimit, in two regions covering a total of 1.70 sr in the southerncelestial hemisphere. The galaxy catalog is drawn primarily from thelist of nonstellar objects identified in the Hubble Space TelescopeGuide Star Catalog (GSC). The galaxies have positions accurate to ~1"and magnitudes with an rms scatter of ~0.3 mag. We compute magnitudes(m_SSRS2) from the relation between instrumental GSC magnitudes and thephotometry by Lauberts & Valentijn. From a comparison with CCDphotometry, we find that our system is homogeneous across the sky andcorresponds to magnitudes measured at the isophotal level ~26 magarcsec^-2. The precision of the radial velocities is ~40 km s^-1, andthe redshift survey is more than 99% complete to the m_SSRS2 = 15.5 maglimit. This sample is in the direction opposite that of the CfA2; incombination the two surveys provide an important database for studies ofthe properties of galaxies and their large-scale distribution in thenearby universe. Based on observations obtained at Cerro TololoInter-American Observatory, National Optical Astronomy Observatories,operated by the Association of Universities for Research in Astronomy,Inc., under cooperative agreement with the National Science Foundation;Complejo Astronomico El Leoncito, operated under agreement between theConsejo Nacional de Investigaciones Científicas de laRepública Argentina and the National Universities of La Plata,Córdoba, and San Juan; the European Southern Observatory, LaSilla, Chile, partially under the bilateral ESO-ObservatórioNacional agreement; Fred Lawrence Whipple Observatory;Laboratório Nacional de Astrofísica, Brazil; and the SouthAfrican Astronomical Observatory.
| 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.
| A comparative study of morphological classifications of APM galaxies
We investigate the consistency of visual morphological classificationsof galaxies by comparing classifications for 831 galaxies from sixindependent observers. The galaxies were classified on laser print copyimages or on computer screen using scans made with the Automated PlateMeasuring (APM) machine. Classifications are compared using the RevisedHubble numerical type index T. We find that individual observers agreewith one another with rms combined dispersions of between 1.3 and 2.3type units, typically about 1.8 units. The dispersions tend to decreaseslightly with increasing angular diameter and, in some cases, withincreasing axial ratio (b/a). The agreement between independentobservers is reasonably good but the scatter is non-negligible. In spiteof the scatter, the Revised Hubble T system can be used to train anautomated galaxy classifier, e.g. an artificial neural network, tohandle the large number of galaxy images that are being compiled in theAPM and other surveys.
| Redshift observations in the Hydra-Centaurus region
The paper reports 406 redshifts for galaxies in the northern galactichemisphere, south of delta = 0 deg. A substantial fraction of theobserved galaxies are located in the equatorial zone between deltavalues of -17.5 and 0 deg. By combining these new data with thoseavailable in the literature, it is possible to extend the original CfAredshift survey of galaxies brighter than m(B(0)) = 14.5 to b = 30 deg,south of delta = 0. New data taken at lower galactic latitudes alsocontribute to the existing surveys of the Hydra-Centaurus complex.
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