As a first step toward constraining the efficiency of the star formation episodes that lead to elliptical (E) and lenticular (S0) K+A galaxies, a survey for HI within a sample of E and S0 K+A galaxies and their likely progenitors (i.e., actively star forming E and S0 galaxies) has been conducted with the NRAO Green Bank Telescope (GBT). The sample was taken from a larger parent sample drawn from the Sloan Digital Sky Survey (SDSS). Here, the GBT data and initial results are discussed. Over half (19 out of 30) of all observed galaxies have detectable 21-cm emission. It was found that both the K+A and star forming early-type (SFE) galaxies were on average more gas poor than disk galaxies at the same luminosity while being more gas rich than more typical E and S0 galaxies with detected 21-cm emission. The gas richness of K+A galaxies appears to be similar to that of SFE galaxies. The star formation rates and estimated star formation time scales of the SFE galaxies imply that they are capable of only marginally changing their atomic hydrogen content. Follow-up observations are required to explore these same issues in terms of molecular gas, which is more likely to actively participate in the star formation process. Kinematic data for the HI gas, the warm ionised gas, and the stars within the galaxies combined with the SDSS $g$ and $i$ band surface brightness profiles imply that the atomic hydrogen is most likely spatially coincident with the star forming regions within ~1 kpc of the galaxies' centres.
We present a summary of high-spatial resolution follow-up observations of the elliptical (E) and lenticular (S0) galaxies in the SAURON survey using the OASIS integral field spectrograph. The OASIS observations explore the central 8x10" regions of these galaxies using a spatial sampling four times higher than SAURON, often revealing previously undiscovered features. Around 75% (31/48) of the SAURON E/S0s with central velocity dispersion >= 120 km/s were observed with OASIS, covering well the original SAURON representative sample. We present here an overview of this follow-up survey, and some p…
We present the stellar kinematics of 48 representative elliptical and lenticular galaxies obtained with our custom-built integral-field spectrograph SAURON operating on the William Herschel Telescope. The data were homogeneously processed through a dedicated reduction and analysis pipeline. All resulting SAURON datacubes were spatially binned to a constant minimum signal-to-noise. We have measured the stellar kinematics with an optimized (penalized pixel-fitting) routine which fits the spectra in pixel space, via the use of optimal templates, and prevents the presence of emission lines to affe…
We examine resolved spectroscopic data obtained with the Keck II telescope for 44 spheroidal galaxies in the fields of two rich clusters, Cl0024+16 (z=0.40) and MS0451-03 (z=0.54), and contrast this with similar data for 23 galaxies within the redshift interval 0.3<z<0.65 in the GOODS northern field. For each galaxy we examine the case for systemic rotation, derive central stellar velocity dispersions sigma and photometric ellipticities, epsilon. Using morphological classifications obtained via Hubble Space Telescope imaging as the basis, we explore the utility of our kinematic quantities in d…
We have measured central line strengths for a complete sample of early type galaxies in the Fornax cluster, comprising 11 elliptical and 11 lenticular galaxies, more luminous than M_B=-17. In contrast to the elliptical galaxies in the sample studied by Gonzalez (and recently revisited by Trager) we find that the Fornax ellipticals follow the locus of galaxies of fixed age in Worthey's models and have metallicities varying from roughly solar to three times solar. The lenticular galaxies however exhibit a substantial spread to younger luminosity weighted ages indicating a more extended star form…
We present in this paper multicolor surface and aperture photometry in the B, V, R and K' bands for a sample of 34 lenticular galaxies from the UGC catalogue. From surface photometric analysis, we obtain radial profiles of surface brightness, colors, ellipticity, position angle and the Fourier coefficients which describe the departure of isophotal shapes from purely elliptical form and find the presence of dust lanes, patches and ring like structure in several galaxies in the sample. We obtain total integrated magnitudes and colors and find that these are in good agreement with the values from…
We present preliminary results from a survey of CO emission from members of a volume-limited sample of non-cluster elliptical galaxies. Our intent is to compare the gas properties of these ellipticals to a sample of lenticulars selected using similar criteria. The data, although still sparse, suggest that the cool gas in ellipticals shows the same puzzling upper mass cutoff found in the lenticular galaxies. We find, however, significantly lower detection rates and possibly much lower H2/HI mass ratios in the ellipticals. The detection rate is higher among the lower-mass galaxies, as has been f…
We present absorption line strength maps of 48 representative elliptical and lenticular galaxies obtained as part of the SAURON survey of nearby galaxies. Using high-quality spectra, spatially binned to a constant signal-to-noise, we measure four key age, metallicity and abundance ratio sensitive indices from the Lick/IDS system over a two-dimensional field extending up to approximately one effective radius. We modify the classical Fe5270 index to define a new index, Fe5270S, which maximizes the usable spatial coverage of SAURON. Maps of Hbeta, Fe5015, Mgb and Fe5270S are presented for each ga…
We present high spatial resolution integral-field spectroscopy of 28 elliptical (E) and lenticular (S0) galaxies from the SAURON representative survey obtained with the OASIS spectrograph during its operation at the CFHT. These seeing-limited observations explore the central 8"x10" (typically one kiloparsec diameter) regions of these galaxies using a spatial sampling four times higher than SAURON (0.27" vs. 0.94" spatial elements), resulting in almost a factor of two improvement in the median PSF. These data allow accurate study of the central regions to complement the large-scale view provide…
We present the emission-line fluxes and kinematics of 48 representative elliptical and lenticular galaxies obtained with our custom-built integral-field spectrograph SAURON. Hb, [OIII], and [NI] emission lines were measured using a new procedure that simultaneously fits both the stellar spectrum and the emission lines. Using this technique we can detect emission lines down to an equivalent width of 0.1A set by the current limitations in describing galaxy spectra with synthetic and real stellar templates, rather than by the quality of our spectra. Emission is detected in 75% of our sample galax…
(Abridged) We present deep WSRT observations of neutral hydrogen in 12 nearby elliptical and lenticular galaxies. The selected objects come from a representative sample of nearby galaxies earlier studied at optical wavelengths with the integral-field spectrograph Sauron. We detect HI - both in regular discs as well as in clouds and tails off-set from the host galaxy - in 70% of the galaxies. This detection rate is much higher than in previous, shallower single-dish surveys, and is similar to that for the ionised gas. The results suggest that at faint detection levels the presence of HI is a re…
We study a sample of 112 galaxies of various Hubble types imaged in the Two Micron All Sky Survey (2MASS) in the Near-Infra Red (NIR; 1-2 $μ$m) $J$, $H$, and $K_s$ bands. The sample contains (optically classified) 32 elliptical, 16 lenticulars, and 64 spirals acquired from the 2MASS Extended Source Catalogue. We use a set of non-parametric shape measures constructed from the Minkowski Functionals (MFs) for galaxy shape analysis. We use ellipticity ($ε$) and orientation angle ($Φ$) as shape diagnostics. With these parameters as functions of area within the isophotal contour, we note that the NI…
We present a photometric and structural analysis of 42 E/S0 galaxies in (E/S0 + S) pairs observed in the BVRI color bands. We empirically determine the effects of interactions on their morphology, structure and stellar populations as seen from the light concentration (C), asymmetry (A), and clumpiness (S) parameters. We further compare these values to a control sample of 67 mostly isolated, non-interacting E/S0 galaxies. The paired E/S0 galaxies occupy a more scattered loci in CAS space than non-interacting E/S0's, and the structural effects of interactions on E/S0's are minor, in contrast to …
This review recaps significant results as they apply to non-dwarf galaxies, including the Milky Way, spiral disks and bulges, and elliptical and lenticular galaxies. Conclusions that span the galaxy types treated here are as follows. All galaxies, on average, have heavy element abundances (metallicities) that systematically decrease outward from their galactic centers while their global metallicities increase with galaxy mass. Abundance gradients are steepest in normal spirals and are seen to be progressively flatter going in order from barred spirals, lenticulars, and ellipticals. For spiral …
We investigate with unprecedented accuracy the correlations between the dynamical mass-to-light ratio M/L and other global observables of E and S0 galaxies. We construct two-integral Jeans and three-integral Schwarzschild dynamical models for a sample of 25 E/S0 galaxies with SAURON integral-field stellar kinematics. We find a tight correlation of the form (M/L)=(3.80+/-0.14)*(sigma/200 km/s)^(0.84+/-0.07) between the dynamical M/L (in the I-band) and the luminosity-weighted second moment (sigma) of the line-of-sight velocity-distribution within Re. The observed rms scatter in M/L for our samp…
We analyse the orbital distribution of E and S0 galaxies using SAURON integral-field stellar kinematics. We construct the anisotropy (V/sigma,epsilon) diagram, for the 48 E/S0 galaxies from the SAURON survey. For a subsample of 24 galaxies consistent with axisymmetry, we use three-integral axisymmetric Schwarzschild dynamical models to recover the detailed orbital distribution and we find good agreement with the anisotropy derived from the (V/sigma,epsilon) diagram. In the companion Paper IX we show that the early-type galaxies can be subdivided into two classes of systems with or without a si…
In this Paper we investigate the kinematical properties of early-type dwarfs by significantly enlarging the scarce observational sample so far available. We present rotation curves and mean velocity dispersions for four bright dwarf ellipticals and two dwarf lenticular galaxies in the Virgo cluster. Most of these galaxies exhibit conspicuous rotation curves. In particular, five out of the six new galaxies are found to be close to the predictions for oblate spheroids flattened by rotation. Therefore, and contrary to the previous observational hints, the present data suggest that an important fr…
(Abridged) We present morphological, photometric, kinematic and line-strength data of 48 early-type members of the rich cluster Abell 2218 at z=0.18. This sample is both larger and spans a wider galaxy luminosity range, down to M*_B+1, than previous studies. We compare A2218 with similar samples drawn from local clusters to identify evolutionary changes between the samples which have occured over the last 3Gyrs. The overall picture is one of little or no evolution in nearly all galaxy parameters. Zeropoint offsets in the Faber--Jackson, Mg_b-sigma and Fundamental Plane relations are all consis…
We have measured central line strengths for a magnitude-limited sample of early-type galaxies in the Fornax cluster, comprising 11 elliptical (E) and 11 lenticular (S0) galaxies, more luminous than MB=-17. When compared with single-burst stellar population models we find that the centres of Fornax ellipticals follow a locus of fixed age and have metallicities varying roughly from half solar to two times solar. The centres of (lower luminosity) lenticular galaxies, however, exhibit a substantial spread to younger luminosity-weighted ages indicating a more extended star formation history. Galaxi…
We report the discovery of a compact object (R_e = 32 pc, M_B = -12.34 mag) at a projected distance of 9 kpc from Messier 59, a giant elliptical in the Virgo cluster. Using HST imaging and SDSS spectroscopy, both available in the Virtual Observatory, we find that this object has a blue core containing one-quarter of the light, and a redder n=1 Sersic envelope, as well as luminosity-weighted age of 9.3 +/- 1.4 Gyr, a metallicity of -0.03 +/- 0.04 dex and a velocity dispersion of 48 +/- 5 km/s. While ultra-compact dwarfs (UCDs) in the face-on view of the Fundamental Plane are found to form a seq…
A kinematical analysis applied to a sample of galaxy clusters indicates that the differences between the velocity distribution of elliptical and spiral galaxies are associated with the shape of their orbit families. The orbital anisotropies present on each morphological population could be measured with the use of a parameter which is the ratio of the radial and tangential velocity dispersions, and can be recovered through the observed line-of-sight velocity distribution. When a Gaussian velocity distribution is assumed, having different dispersions along the radial and tangential directions, …
Many early-type galaxies have been detected at wavelengths of 24 to 160 micron, but the emission is usually dominated by heating from an AGN or from the evolved stellar population. Here we present Spitzer MIPS observations of a sample of elliptical and lenticular galaxies that are rich in cold molecular gas, and we investigate whether the MIR to FIR emission could be associated with star formation activity. The 24 micron images show a rich variety of structures, including nuclear point sources, rings, disks, and smooth extended emission. Comparisons to matched-resolution CO and radio continuum…
Near-IR spectra for a sample of 31 elliptical galaxies in the Coma cluster are obtained. The galaxies are selected to be ellipticals (no lenticulars), with a large spatial distribution, covering both the core and outskirt of the cluster (ie. corresponding to regions with large density contrasts). Spectroscopic CO (2.3 micron) absorption indices, measuring contribution from intermediate-age red giant and supergiant stars to the near-IR light of the ellipticals, are then estimated. It is found that the strength of spectroscopic CO features in elliptical galaxies increases from the core (r < 0.2 …
We compare [alpha/Fe], metallicity, and age distributions of globular clusters in elliptical, lenticular, and spiral galaxies, which we derive from Lick line index measurements. We find a large number of globular clusters in elliptical galaxies that reach significantly higher [alpha/Fe] values (>0.5) than any clusters in lenticular and spiral galaxies. Most of these extremely alpha-enriched globular clusters are old (t > 8 Gyr) and cover the metallicity range -1 <~ [Z/H] <~ 0. A comparison with supernova yield models suggests that the progenitor gas clouds of these globular clusters must have …
We present kinematics and stellar population properties of 17 dwarf early-type galaxies in the luminosity range -14> M_B> -19. Our sample fills the gap between the intensively studied giant elliptical and Local Group dwarf spheroidal galaxies. The dwarf ellipticals of the present sample have constant velocity dispersion profiles within their effective radii and do not show significant rotation, hence are clearly anisotropic. The dwarf lenticulars, instead, rotate faster and are, at least partially, supported by rotation. From optical Lick absorption indices, we derive metallicities and element…
We have performed TreeSPH simulations of galaxy formation in a standard LCDM cosmology, including effects of star formation, energetic stellar feedback processes and a meta-galactic UV field, and obtain a mix of disk, lenticular and elliptical galaxies. The disk galaxies are deficient in angular momentum by only about a factor of two compared to observed disk galaxies. The stellar disks have approximately exponential surface density profiles, and those of the bulges range from exponential to r^{1/4}, as observed. The bulge-to-disk ratios of the disk galaxies are consistent with observations an…
We present a spectroscopic sample of 48 early-type galaxies in the rich cluster Abell 2218 and 50 galaxies in Abell 2390. Since both samples are very similar, we combine them and investigate a total number of 98 early-type galaxies at z~0.2. A subsample of 34 galaxies with HST structural properties is used to construct the Fundamental Plane. Elliptical and S0 galaxies show a zeropoint offset of m_r~0.43 mag with respect to the local Coma FP. Both sub-samples, ellipticals and lenticulars, exhibit a similar, mild evolution and small scatter. The moderate amount of luminosity evolution is consist…
M32 is the prototype for the relatively rare class of galaxies referred to as `compact ellipticals'. It has been suggested that M32 may be a tidally disturbed r^(1/4) elliptical galaxy, or the remnant bulge of a disk-stripped early-type spiral galaxy. This paper reveals that the surface brightness profile, the velocity dispersion measurements, and the estimated supermassive black hole mass in M32 are inconsistent with the galaxy having, and probably ever having had, an r^(1/4) light profile. Instead, the radial surface brightness distribution of M32 resembles an almost perfect (bulge + exponen…
We investigate a spectroscopic sample of 48 early-type (E+S0) galaxies in the rich cluster Abell 2390 (z=0.23) and 48 E+S0 galaxies from a previously published survey of Abell 2218 (z=0.18). The A2390 spectra are based on Multi Object Spectroscopy with MOSCA at the Calar Alto 3.5-m, complemented by ground-based and HST F555W and F814W observations. Our investigation spans a broad range in luminosity (-20.5>M_r>-23.0) and a wide FOV of 1.5x1.5 Mpc^2. Since the A2218 and A2390 samples are very similar, we can combine them and analyse a total of 96 E+S0 galaxies at z~0.2. We construct the Faber-J…
We present near-infrared K-band spectroscopy of 21 elliptical or cD Brightest Cluster Galaxies (BCGs), for which we have measured the strength of the 2.293 micron CO stellar absorption feature. We find that the strength of this feature is remarkably uniform among these galaxies, with a smaller scatter in equivalent width than for the normal elliptical population in the field or clusters. The scatter for BCGs is 0.156 nm, compared with 0.240 nm for Coma cluster ellipticals, 0.337 nm for ellipticals from a variety of other clusters, and 0.422 nm for field ellipticals. We interpret this homogenei…
Early-type galaxies, considered as large bulges, have been found to have had a much-more-than-boring star formation history in recent years by the UV satellite GALEX. The most massive bulges, brightest cluster galaxies, appear to be relatively free of young stars. But smaller bulges, normal ellipticals and lenticulars, often show unambiguous sign of recent star formation in their UV flux. The fraction of such UV-bright bulges in the volume-limited sample climbs up to the staggering 30%. The bulges of spirals follow similar trends but a larger fraction showing signs of current and recent star f…
We study the UV properties of a volume limited sample of early-type galaxies in the Virgo cluster combining new GALEX far- (1530 A) and near-ultraviolet (2310 A) data with spectro-photometric data available at other wavelengths. The sample includes 264 ellipticals, lenticulars and dwarfs spanning a large range in luminosity (M(B)<-15). While the NUV to optical or near-IR color magnitude relations (CMR) are similar to those observed at optical wavelengths, with a monotonic reddening of the color index with increasing luminosity, the (FUV-V) and (FUV-H) CMRs show a discontinuity between massive …
Because of its proximity and richness on late-type galaxies, the Virgo cluster has been the subject of numerous studies exploring the effect of the intracluster environment on galaxy evolution. First discovered nearly three decades ago by Davies & Lewis (1973), the neutral hydrogen (HI) deficiency of the Virgo galaxies is now a well-established observational phenomenon also observed on many other rich clusters. A number of studies on the neutral hydrogen 21-cm line of Virgo cluster galaxies --from the lenticular and largest spiral types through the faintest dwarf irregulars-- show that a signi…
We examine the origin of photometrical properties of N-body merger remnants from the perpective of their orbital content. We show that disc mergers alone are unlikely to form a boxy-discy dichotomy in isophotal shape, because of the survival of disc-like orbits even in violent mergers. The shape of the different orbit families can vary strongly, depending on how violent the merger was. Minor axis tubes can become boxy and box orbits can be round. However, for edge-on projections isophotal shape, orbital content and line-of-sight velocity are well connected.
A variety of host galaxy (bulge) parameters are examined in order to determine their predictive power in ascertaining the masses of the supermassive black holes (SMBH) at the centers of the galaxies. Based on a sample of 23 nearby galaxies, comprised of both elliptical galaxies and spiral/lenticular bulges, we identify a strong correlation between the bulge gravitational binding energy ($E_g$), as traced by the stellar light profile, and the SMBH mass ($M_{\bullet}$), such that $M_{\bullet} \propto E_g^{0.6}$. The scatter about the relationship indicates that this is as strong a predictor of $…
We support, with new fitting instruments and the analysis of more recent experimental data, the proposal of a relationship between the mass of a Supermassive Black Hole (SMBH) and the kinetic energy of random motions in the host elliptical galaxy. The first results obtained in a previous paper with 13 elliptical galaxies are now confirmed by the new data and an enlarged sample. We find $M_{BH} \propto (M_{G} σ^{2}/c^2)^β$ with $0.8 \leq β\leq 1$ depending on the different fitting methods and samples used. The meaningful case $β= 1$ is carefully analyzed. Furthermore, we test the robustness of …
We present spectral analysis of ASCA data of 17 elliptical and 3 lenticular galaxies most of which have high L_x/L_B. Single-temperature models (MEKAL and Raymond-Smith) give unacceptable fits (chi^2_red > 1.5) in most cases and, in agreement with previous studies, give very sub-solar abundances, <Z> = 0.19 +/- 0.12 Z_sun (MEKAL). The spectra for approximately half the sample are better fit with a cooling-flow model which in three cases gives a substantially better fit. The abundances derived from the cooling-flow model are also significantly larger, <Z> = 0.6 +/- 0.5 Z_sun. We empirically tes…
Under the merger hypothesis, elliptical galaxies are built through mergers of gas-rich spirals. However, the relative paucity of HI in most normal ellipticals demands significant processing of atomic gas into other forms if this process is to be viable. Here I present a few qualitative remarks on how the properties of merger-spawned ellipticals might depend on the (evolving) gas content of the progenitor disks, then turn to a more quantitative study of the constraints provided by the nuclear properties of ellipticals and merger remnants.
We revisit the shapes of isophotes for elliptical (E) and lenticular (S0) galaxies by studying 847 nearby early-type galaxies selected from the Sloan Digital Sky Survey Data Release 4 with velocity dispersions above 200 km/s. The IRAF task {\tt ellipse} was used to derive the deviations of the isophotes from pure ellipses (Fourier coefficients a_3/a and a_4/a), position angles and ellipticities as a function of radius. We show the statistical distributions of the a_3/a and a_4/a parameters as a function of velocity dispersion, magnitude, and colour. The a_4/a parameter is correlated with the e…
Images taken with the IRAC instrument on the Spitzer Space Telescope show that the spatial distribution of warm dust emission in lenticular galaxies is often organized into dynamically-stable structures strongly resembling spiral arms. These galaxies have bulge-to-disk-ratios and colors for their stellar content appropriate for their morphological classification. Two of the three galaxies with warm dust detected at 8.0 um also show far-IR emission expected from that dust. More importantly, the [5.8]-[8.0] color of the dust emission matches the colors found for late-type, star-forming galaxies,…
We apply detailed observations of the Color-Magnitude Relation (CMR) with the ACS/HST to study galaxy evolution in eight clusters at z~1. The early-type red sequence is well defined and elliptical and lenticular galaxies lie on similar CMRs. We analyze CMR parameters as a function of redshift, galaxy properties and cluster mass. For bright galaxies (M_B < -21mag), the CMR scatter of the elliptical population in cluster cores is smaller than that of the S0 population, although the two become similar at faint magnitudes. While the bright S0 population consistently shows larger scatter than the e…
We present B-band imaging of 18 low redshift (z<0.3) BL Lac objects for which their host galaxies were previously resolved in the R-band and the near-infrared H-band. For a subset of the objects, also U- and V-band imaging is presented. These data are used to investigate the blue-red-near-infrared colours and the colour gradients of the host galaxies of BL Lacs in comparison with other elliptical galaxies with and without nuclear activity. In all cases galaxies are well represented by an elliptical model, with average absolute magnitude M_B=-21.6+-0.7 and average scale length R_e=7.6+-3.2 kpc.…
We present results from two mid-infrared imaging programs of ultraluminous infrared galaxies (ULIRGs) and fine-structure elliptical galaxies. The former are known to nearly all be recent mergers between two gas-rich spiral galaxies, while the latter are also believed to be even more aged merger remnants. An examination of these two classes of objects, which may represent different stages of the same putative merger sequence, should reveal similarities in the distribution of their stellar populations and dust content consistent with that expected for time-evolution of the merger. The data revea…
We use HST/ACS imaging of 100 early-type galaxies in the ACS Virgo Cluster Survey to investigate the nature of diffuse star clusters (DSCs). Compared to globular clusters (GCs), these star clusters have moderately low luminosities (M_V > -8) and a broad distribution of sizes (3 < r_h < 30 pc), but they are principally characterized by their low mean surface brightnesses which can be more than three magnitudes fainter than a typical GC (mu_g > 20 mag arcsec^-2). The median colors of diffuse star cluster systems are red, 1.1 < g-z < 1.6, which is redder than metal-rich GCs and often as red as th…
Elliptical galaxies outside dense clusters are observed to contain small amounts (relative to spiral galaxies) of cold interstellar gas. This review discusses the atomic gas, the molecular gas, and the dust in elliptical galaxies. Field elliptical galaxies contain about 0.01 to 0.1 of the cold interstellar matter content of spiral galaxies of similar luminosity, and support a low level of star formation. The surface densities of cold gas clouds in the centers of some elliptical galaxies are comparable to those in the densest regions of the Galactic disk. These observations suggest that ellipti…
We present a detailed investigation of the relation between the orbital content of merger remnants and observable properties of elliptical and S0 galaxies. Our analysis is based on the statistical sample of collisionless mergers of disk galaxies with different mass ratios and orbital parameters, published by Naab & Burkert. We use the spectral method by Carpintero & Aguilar to determine the orbital content of every remnant and correlate it with its intrinsic shape, and its projected kinematic and photometric properties. We discuss the influence of the bulge component and varying pericenter dis…
In models of galaxy formation in a hierarchical Universe, elliptical galaxies form through the merging of smaller disk systems. These models yield a number of testable predictions if reliable techniques for determining the relative ages and compositions of the stellar populations of different galaxies can be found: 1) ellipticals in low-density environments form later than ellipticals in clusters, 2) more massive ellipticals form later, 3) more massive ellipticals form in dissipationless mergers from disk galaxies with low gas content. While colours and the Balmer line strengths of galaxies ca…
There are strong indications from recent papers (e.g. Worthey et al. 1992) that the abundance ratio of Mg/Fe, and consequently also O/Fe in giant elliptical galaxies is not solar. The line strengths of two Fe lines at 5270 and 5335 A are weaker than one expects from the strength of the Mg b line if [Mg/Fe] = 0. We have synthesized absorption line indices to derive the Mg and Fe abundances of these galaxies. For these models we have calculated new evolutionary tracks of high metallicity stars with a range of Mg/Fe abundances. This is the first time that such tracks have been generated. Integrat…
We present photometric analysis of a local sample of 14 isolated pairs of galaxies. The photometric properties analyzed in the local pairs are: colors, morphology, tidal effects and activity. We verify that close pairs have an excess of early-type galaxies and many elliptical galaxies in this pairs are, in fact, lenticular galaxies. Many late-pairs in our sample show strong tidal damage and blue star formation regions. We conclude that pairs of different morphologies may have passed through different evolution processes which violently transformed their morphology. Pairs with at least one earl…
In this paper we explore several structural and dynamical effects on the projected velocity dispersion as possible causes of the fundamental plane (FP) tilt of elliptical galaxies. Specifically, we determine the size of the systematic trend along the FP in the orbital radial anisotropy, in the dark matter (DM) content and distribution relative to the bright matter, and in the shape of the light profile that would be needed to produce the tilt, under the assumption of a constant stellar mass to light ratio. Spherical, non rotating, two--components models are constructed, where the light profile…
The detection of resonance absorption lines against known objects such as individual galaxies and clusters of galaxies is a powerful approach for studying the gas content of these systems. We describe an efficient method of identifying background quasars suitable for absorption line studies. In this finding technique, we identify serendipitous X-ray sources, about 1/8 of which are suitably bright quasars at moderate redshift. We identify 16 new quasars and galaxies with active galactic nuclei (AGNs), and confirm 5 known quasars and AGNs, superimposed behind elliptical galaxies and clusters of …
The formation of elliptical galaxies as a result of the merging of spiral galaxies is discussed. We analyse a large set of numerical N-Body merger simulations which show that major mergers can in principle explain the observed isophotal fine structure of ellipticals and its correlation with kinematical properties. Equal-mass mergers lead to boxy, slowly rotating systems, unequal-mass mergers produce fast rotating and disky ellipticals. However, several problems remain. Anisotropic equal mass mergers appear disky under certain projections which is not observed. The intrinsic ellipticities of re…
Evolutionary models of elliptical galaxies are constructed by using a new population synthesis code. Model parameters are calibrated to reproduce the observed colour-magnitude (CM) relation of Coma ellipticals in $V-K$ vs. $M_{V}$ diagram. The SEDs are degenerated in stellar age and metallicity. An attempt is performed to break this degeneracy, by simulating evolution of the CM relation of elliptical galaxies, based on the two alternative interpretations; i.e., the CM relation reflects different mean stellar age or various stellar metallicity. A confrontation with the CM diagrams of E/S0 galax…
We present HI 21cm line observations, obtained with the Australia Telescope Compact Array, of two dwarf elliptical galaxies (dEs) in the Fornax cluster: FCC032 and FCC336. The optical positions and velocities of these galaxies place them well within the Fornax cluster. FCC032 was detected at the 3sigma significance level with a total HI flux density of 0.66+-0.22 Jy km s^-1 or an HI mass of 5.0+-1.7 10^7 h_75^-2 M_sun. Based on our deep Halpha+[NII] narrow-band images, obtained with FORS2 mounted on the VLT, this dE was already known to contain 600-1800 h_75^-2 M_sun of ionised Hydrogen (depen…
Many early-type galaxies are detected at 24 to 160 micron but the emission is usually dominated by an AGN or heating from the evolved stellar population. Here we present MIPS observations of a sample of elliptical and lenticular galaxies which are rich in cold molecular gas, and we investigate how much of the MIR to FIR emission could be due to star formation activity. The 24 micron images show a rich variety of structures, including nuclear point sources, rings, disks, and smooth extended emission, and comparisons to matched-resolution CO and radio continuum images suggest that the bulk of th…
Essentially all Ultra-Luminous IR Galaxies (ULIRGs) are in disturbed, interacting or merging systems. It is known that interactions tend to induce galactic starbursts. Thus, elliptical galaxies which are formed in mergers will tend to have high metallicity, low dust and molecular gas content, and faint structural distortions, as observed for the bone fide elliptical galaxy population. The old stellar population in the merged galaxies will probe the new gravitational potential, relaxing rapidly to give a de Vaucouleurs surface-brightness profile if the remnant is elliptical-like. We examine the…
Substantial numbers of morphologically regular early-type (elliptical and lenticular) galaxies contain molecular gas, and the quantities of gas are probably sufficient to explain recent estimates of the current level of star formation activity. This gas can also be used as a tracer of the processes that drive the evolution of early-type galaxies. For example, in most cases the gas is forming dynamically cold stellar disks with sizes in the range of hundreds of pc to more than one kpc, although there is typically only 1% of the total stellar mass currently available to form young stars. The num…
Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. It is argued that cluster metallicity ($\sim 1/3$ solar) should be taken as representative of the low-$z$ universe as a whole. There is now compelling evidence that the bulk of stars not only in cluster ellipticals but also in field ellipticals and bulges formed at high redshifts ($z\gsim 3$). Since such stars account for at least $\sim 30%$ of the baryons now locked into stars, it is argued that at least 30% of stars and metals formed before $z\simeq 3$, and correspondingly …
A detailed model of galactic evolution is proposed to explain both the iron content of the Intra-Cluster Medium (ICM) and of the ellipticals pertaining to the cluster. SNII are responsible for the production of Fe in the galaxies and of its partial ejection in the surrounding medium. A high formation rate of massive stars only ($m>3~{\rm M_{\sun}}$) at the very early stage of evolution of ellipticals, reminiscent of starburst galaxies, is advocated. The high rate of SNII explosions induces a powerful galactic wind, followed by a more quiescent evolution where stars are formed, with a normal In…
We present estimates of the GALEX NUV and FUV luminosity functions (LFs) of the Coma cluster, over a total area of ~9 deg^2 (~25 Mpc^2), i.e. from the cluster center to the virial radius. Our analysis represents the widest and deepest UV investigation of a nearby cluster of galaxies made to date. The Coma UV LFs show a faint-end slope steeper than the one observed in the local field. This difference, more evident in NUV, is entirely due to the contribution of massive quiescent systems (e.g. ellipticals, lenticulars and passive spirals), more frequent in high density environments. On the contra…
We present analysis of a Chandra observation of the elliptical galaxy NGC 4555. The galaxy lies in a very low density environment, either isolated from all galaxies of similar mass or on the outskirts of a group. Despite this, NGC 4555 has a large gaseous halo, extending to ~60 kpc. We find the mean gas temperature to be ~0.95 keV and the Iron abundance to be ~0.5 solar. We model the surface brightness, temperature and abundance distribution of the halo and use these results to estimate parameters such as the entropy and cooling time of the gas, and the total gravitational mass of the galaxy. …
