Isophote shape and flattening are being used for studying a similarity between elliptical and lenticular galaxies.

Several statistical attempts were already made to discriminate between oblate forms vs. prolate forms (OF/PF) in elliptical galaxies (Marchant & Olson, 1979; Lake, 1979; Olson & de Vaucouleurs, 1981; Capaccioli et al., 1984). They fell in with the fundamental problem that the observed quantities (surface brightness, velocity dispersion, flattening etc.) whose projection should depend on the assumed shapes (OF/PF), could be intrinsically correlated each other. This can mask the simple projection–effect (Richstone, 1979; Merritt, 1982).

A general discussion, based on the ht “Fourier Slice Theorem,” is given for the problem of deprojecting the observed light distribution of galaxies to obtain their intrinsic three dimensional light distribution or “shape.” Several results are obtained: 1) A model-independent deprojection of an axially symmetric galaxy is shown to be possible only if the symmetry axis lies in the plane of the sky. 2) A simple criterion is given to test whether two different galaxies can have the same intrinsic shape, based solely on their observed projections. 3) It is shown that a homogeneous class of galaxies can be deprojected using a sufficiently large number of projections of random perspective.

The apparent rotation curve of cold gas in a triaxial potential often differs from that in an axisymmetric system in characteristic ways. The data argue for triaxial bulges in our Galaxy and several others.

We present a method, partly geometrical and partly dynamical, to determine the intrinsic axial ratios of a triaxial galaxy. The method can be applied to bulges of spiral galaxies and to ellipticals containing sufficiently extended and kinematically regular gas disks. Required observational inputs are multi-colour surface photometry and the gas velocity field.

Prominent gas disks and dust lanes are found in a number of elliptical galaxies. It is widely believed that these disks are the result of the tidal capture of material from a nearby galaxy or the accretion of a gas rich companion into a larger galaxy. While a captured gas disk will ultimately settle into a steady-state orientation (“preferred plane”), the disk will initially be time varying due to precessional and viscous forces. We have developed methods for modeling the evolution of such inclined dissipative galactic gas disks (Steiman-Cameron 1984, Ph.D. dissertation, Indiana U.; Steiman-Cameron and Durisen 1986, Ap.J., in press, hereafter SCD), and we here present some of the results of this work.

A program of CCD imaging of early-type galactic nuclei carried out at the Canada-France-Hawaii Telescope (Kormendy, these proceedings) reveals dust in an unusually large fraction of the galaxies. Often the dust is in a ring or disk whose radius is comparable to the core radius rc; since rc is small, our detection rate benefits from the excellent CFHT seeing (median FWHM = O.“7; scale = O.“22 pixel−1 for an RCA CCD used at the Cassegrain focus). We plan to prepare a photographic atlas of unsharp-masked images, and to study correlations between dust properties and nuclear emission lines, HI and X-ray gas content, radio continuum jets and the overall light distributions of the program galaxies.

We present preliminary results of a detailed photometric study of NGC 6702, from high resolution photographs taken at the Cassegrain focus of the Canada-France-Hawaii (CFH) telescope. The luminosity distribution of the galaxy follows an r1/4 law (re* = 11.6″, μe* = 22.17). The axis ratio is 0.75 (corresponding to the morphological type E3) and the position angle of the major axis is 60 and fairly constant. Fig. 1 is an image in intensity of the galaxy, from a 30mn exposure in B. The galaxy is crossed by a dust lane, reported first by Capaccioli et al. (1984).

The CCD camera of the Landessternwarte Heidelberg was used at the 1.2 m Calar Alto Telescope for a V, R, I - survey of ~70 dusty and non-dusty elliptical galaxies. We report here about morphological studies of ten bright elliptical galacxies in the Virgo cluster. After the usual CCD data reduction the following procedures were carried through:

1. The CCD-frames were filtered and centered to an accuracy of ~ 0. 2 pixels. By division we obtained V-R, V-I, R-I color index images which allow to separate dust absorption and gaseous emission from the stellar distribution. Five of the 1 0 bright Virgo ellipticals evidently show dust/gas, two other objects have weak features. The dust lanes in NGC k26 (cf. Fig. l), NGC 4365 and NGC 4552 were detected for the first time. A dust lane must be visible in all three color index frames in order to avoid fake identifications.

2. The isophotes in all three colors were fitted by least square ellipses. From these fits we obtained in dependence from the radius: color profiles, color index profiles, ellipticity profiles, isophote twists (cf. Fig. 2). The deviations of the isophotes from ideal ellipses were studied by a Fourier series analysis. The fourth coefficient is the main indicator for such deviations. Six of ten galaxies show box-shaped isophotes of an amount between 0. 3 % and 1. 5 % of the semi major axis (cf. Fig. 3) 5 two galaxies show disc components (0. 8 1.5 %), only one galaxy is a perfect elliptical up to an error of ±0.2 %. The deviations are equal in all three colors and therefore are not produced by dust.

Photometic and kinematic observations are presented for the box-shaped “elliptical” galaxy IC 3370, that show that this galaxy has characteristics more akin to an S0 galaxy than an elliptical and should be classified Sopec.

Photometric and spectroscopic observations show that the inner component of AM2020—5050 is an elliptical galaxy, unlike other polar-ring galaxies which have an SO disk at the center. A comparison of the central velocity dispersion with the rotational velocity in the ring suggests the presence of a nearly spherical gravitational potential. The inner component has a rapidly rotating core with rotational velocities at 3″ substantially higher than at 8″. Although the optical ring is quite narrow, Hα emission is observed all the way through the center of the galaxy, indicating the presence of an extended gaseous disk.

By use ot the TAURUS imaging Fabry–Perot interferometer (Taylor & Atherton 1980) we have obtained seeing limited two–dimensional velocity, line width and line flux maps of the ionised gas in two polar ring systems.

The TAURUS Imaging Fabry-Perot System (Taylor & Atherton 1980) has been used with the IPCS at the AAT to observe the ionized gas within NGC 5128 (Cen A) at [NII]λ6548 and Hα. Seven independent (x, y,λ) data cubes were obtained along the dust lane at high spectral resolution (30 km/s FWHM) and at a spatial resolution limited by the seeing (~1″). From these data, maps of the kinematics and intensities of the ionized gas were derived over a 420″ by 300″ region. The maps are the most complete to date for this object comprising 17500 and 5300 fitted spectra in Ha and [NII]λ6548 respectively. The dust lane system is found to be well understood in terms of a differentially rotating disc of gas and dust which is warped both along and perpendicular to the line-of-sight.

We present Fabry–Perot spectrophotometry of the well-known peculiar galaxy Cen A (NGC 5128). The observations were carried out using the Rutgers Fabry–Perot system and a CCD as a detector. We scanned the Hα and [NII] (λ6583) emission lines. From these data we were able to construct maps of the continuum, line emission, velocity and velocity dispersion. The velocity maps in both Hα and [NII] have smooth gradients and twists in the line of nodes. The deprojected emission maps strongly resemble emission maps of face-on spirals. We speculate that Cen A is a merger between an elliptical and a spiral.

Statistics on HI absorption in radio galaxies suggest that accretion of gas into the center might be a general phenomenon. Images of the HI emission from these galaxies show that the gas must have an external origin. The rotation curves derived from the HI data are flat.

I have detected 21 cm line emission from neutral hydrogen in the giant elliptical galaxy NGC 807 at Arecibo Observatory, and I have mapped this emission with the VLA. Unlike the active and dwarf ellipticals that have been mapped thus far, NGC 807 has a fairly regular disk of gas rotating about the apparent optical minor axis. Combined with observations of active ellipticals, this observation suggests that two classes of HI-rich ellipticals may exist: ellipticals which have accreted gas and become active recently, and quiescent ellipticals which have either produced gas internally or accreted it so long ago that it has reached dynamical equilibrium.

CCD data are used to compare the isophotes, colour and dust-content of radio (1021<P5GHz<1024WHz-1, HO = 75kms-1Mpc-1) and radio-quiet ellipticals. Radio ellipticals are round but not spheroidal, reddened and occasionally have disturbed dust lanes. X-ray emission correlates with both radio emission and shape. Detailed investigations of dust in NGC 1316 reveal a possible nuclear gas disc orthogonal to the radio jet.

Near infrared polarimetry of Centaurus A and IC5063 has revealed the existence of a steep spectrum highly polarized source in the nuclei of both galaxies. The position angle of polarization is perpendicular to the radio position angle. We interpret this polarized emission as synchrotron radiation. This, together with a luminosity of 5 × 1041erg s-1, suggests the galaxies are low luminosity blazars and that such nuclei may be common in elliptical galaxies.

Stellar kinematical and dynamical results are presented for 34 radio ellipticals. The radio galaxies we observed were brighter than m(B)=16. The results show that these radio ellipticals are not generally more rapidly rotating than their non-radio counterparts. Evidence for some rotation about the major axis is seen in two cases. These radio ellipticals do not appear to obey the luminosity, velocity dispersion trend seen for normal ellipticals.

We have studied a sample of 81 E and SO galaxies (taken mostly from the literature) that were observed with the Einstein Observatory. Fifty–five galaxies are detected in X–rays, most of which come from a hot interstellar medium. It is possible that discrete sources make a significant contribution to the X–ray emission for 21 of the detected galaxies with the lowest X–ray luminosity, LX, for a given optical luminosity, LB. We examine the LX vs. LB distribution (see Figure 1), and derive approximate values of the central electron density, central cooling time and total mass in gas for the sample. Typical values are ~ 0.1cm−3, ~ 5 × 106 yr and 5 × 109M⊙, respectively. The short cooling times suggest the presence of cooling flows, and we consider heating by supernovae and by gravitational processes. Supernovae at the accepted rate would overproduce the observed X–ray luminosity: either the true rate is many times lower or the supernova energy is not well coupled to the hot gas. There are also difficulties in explaining the suppression of a strong galactic wind if supernova heating dominates, unless an external pressure confines the gas. Gravitational heating gives LX ∝ LBσ2, where σ is the line–of–sight velocity dispersion in the galaxy, and we find that this is roughly the case. Gravitational heating exceeds the mean observed Lx by a factor of ~ 3 — 4 if one uses the accepted rate of stellar mass loss and assumes that the gas falls all the way to the center of the galaxy. This could be reconciled if the mass injection rate were lower or if matter drops out of the flow at all radii. The sample properties provide no additional information about the presence or absence of heavy halos in early type galaxies.