The accompanying tables and images are part of a pictorial atlas of UV ( 2300 Ang) images, obtained with the Faint Object Camera of the Hubble Space Telescope, of the central 22''x 22'' of 110 galaxies. The observed galaxies are an unbiased selection constituting about one half of a complete sample of all large (D>6 arcmin) and nearby (V< 2000 km/s ) galaxies. This is the first extensive UV imaging survey of normal galaxies. The data are useful for studying star formation, low-level nuclear activity, and UV emission by evolved stellar populations in galaxies. At the FOC resolution (~ 0.05''), the images display an assortment of morphologies and UV brightnesses. These include bright nuclear point sources, compact young star clusters scattered in the field or arranged in circumnuclear rings, centrally-peaked diffuse light distributions, and galaxies with weak or undetected UV emission. We measure the integrated ~2300 Ang flux in each image, and classify the UV morphology. The UV and optical parameters are given in the tables.
The jpeg images below are grey-scale representations of the FOC images after standard pipeline reduction. Each image has a scale of 22''X 22'' and has been rotated so that north is up and east is left. Archival exposures are marked with an "a" next to the galaxy NGC number, and in some cases have a different field of view and sensitivity. For details see the notes accompanying individual objects. The grey scale of each image is chosen to bring out the most interesting details. However, these snapshots cannot convey all of the useful information in many of the images. We advise the user to refer to the notes or to retrieve the actual FITS data if complete details are required. This is true both for bright sources, where a single grey scale cannot show details of different contrast, and for weak sources ("W-type" morphology) for which the faint emission is lost in the reproduction.
The parameters of the 110 observed galaxies are listed in
Table 1 (southern galaxies) and Table 2 (northern galaxies).
Following is a column-by-column description of the
table entries, and how they are derived.
(1) NGC designation of the galaxy.
An ``a'' next to the number denotes archival images, generally obtained
with a different FOC format, filter, or exposure time than those of the program galaxies.
See Section 3.3 for details.
(2) UGC designation of the galaxy (northern galaxies only).
(3) 1950 coordinates, to one-minute accuracy, as listed in the UGC and ESO catalogs. This datum can be useful for unambiguously identifying the galaxies in these and other catalogs, since listed coordinates for such large galaxies may vary by arcminutes from catalog to catalog. Also, some galaxies in the ESO catalog are designated solely by means of these coordinates.
(4)(5) J2000 coordinates of the nucleus, as measured in the STScI GASP system
(see Section 2). These coordinates are generally accurate to ~ 1''-2''.
(6) V_h -- Heliocentric velocity, as listed in the UGC or ESO catalogs, in km/s.
The selection criterion for inclusion in the sample was V_h < 2000 km/s.
(7)(8) D_a, D_b -- Major and minor axis diameters, in tenths of arcminutes, from the UGC and ESO catalogs. The selection criterion for inclusion in the sample was D_a > 60.
(9) B_mag -- Integrated B magnitude, from the UGC and ESO catalogs.
(10) T -- Hubble type, using de Vaucouleurs' T-type classification from the
RC3 catalog (de Vaucouleurs et al. 1991). The correspondence is approximately as follows;
E: -6 to -4; S0: -3 to 0 ; Sa: 1; Sb: 3; Sc: 5; Sd: 7; Irr: 10.
(11) Classif. -- Hubble type and luminosity class using the classification, when available, from the Revised Shapley-Ames Catalog of Bright Galaxies (Sandage & Tammann 1987).
(12) Sp. -- (northern galaxies only) -- Spectral classification of the nucleus,
from Ho et al. (1995, 1996a). The designation is as follows.
(13) HST UT observation date.
(14) Image rootname in the HST archive, useful for retrieving the actual data.
L -- LINER (low-ionization nuclear emission-line region);
H -- H II nucleus; T -- ``transition'' source, between LINER and H II;
S -- Seyfert nucleus; A -- ``absorption-line'' nucleus with no detected emission lines. A colon
denotes an uncertain classification. The Ho et al. classification is based on the Filippenko & Sargent (1985, 1986) optical spectroscopic survey of the nuclei of a flux-limited (B < 12.5 mag) sample of 486 northern galaxies. All but three of the northern galaxies in the HST survey (which is diameter- and redshift-limited) are included in the Filippenko & Sargent (1985) sample. The effective aperture of the optical observations is 2''x 4''. The Ho et al. (1996a) classification is assigned after careful subtraction of absorption-line template spectra, leaving behind only the emission-line residual; see Ho et al. (1996a) for further details.