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Surface photometry of binary galaxies. I. A multicolour study of morphologies due to the interaction

We present the multicolour (B, V, R) surface photometry of 53 double galaxies. All the pairs belong to the catalogue of Reduzzi & Rampazzo (1995) containing objects selected according to the Karachentsev (1972) criteria. We comment on the morphological, structural and photometric characteristics of pairs and their members. Different classes of interaction induced phenomena, both...

NGC 3934: a shell galaxy in a compact galaxy environment

Context. Mergers/accretions are considered the main drivers of the evolution of galaxies in groups. We investigate the NGC 3933 poor galaxy association that contains NGC 3934, which is classified as a polar-ring galaxy.Aims. The multi-band photometric analysis of NGC 3934 allows us to investigate the nature of this galaxy and to re-define the NGC 3933 group members with the aim...

NGC 3934: a shell galaxy in a compact galaxy environment

Context. Mergers/accretions are considered the main drivers of the evolution of galaxies in groups. We investigate the NGC 3933 poor galaxy association that contains NGC 3934, which is classified as a polar-ring galaxy.Aims. The multi-band photometric analysis of NGC 3934 allows us to investigate the nature of this galaxy and to re-define the NGC 3933 group members with the aim...

Mid-infrared colour gradients and the colour–magnitude relation in Virgo early-type galaxies

We make use of Spitzer imaging between 4 and 16 μm and near-infrared data at 2.2 μm to investigate the nature and distribution of the mid-infrared emission in a sample of early-type galaxies (ETGs) in the Virgo cluster. These data allow us to conclude, with some confidence, that the emission at 16 μm in passive ETGs is stellar in origin, consistent with previous work concluding...

Galaxy evolution in nearby loose groups – II. Photometric and kinematic characterization of USGC U268 and USGC U376 group members in the Leo cloud★

This paper is the second of a series of papers in which we are exploring the coevolution of galaxies and groups in the local Universe, by adopting a multiwavelength approach. Here, we present the photometric and kinematic characterization of two groups, USGC U268 and USGC U376 (U268 and U376 hereafter), which are located in different regions of the Leo cloud. We revisit the group...

Nearby early-type galaxies with ionized gas - IV. Origin and powering mechanism of the ionized gas

Aims. A significant fraction of early-type galaxies (ETGs) exhibit emission lines in their optical spectra. We attempt to identify the producing the emission mechanism and the ionized gas in ETGs, and its connection with the host galaxy evolution.Methods. We analyzed intermediate-resolution optical spectra of 65 ETGs, mostly located in low density environments and exhibiting...

Nearby early-type galaxies with ionized gas: the UV emission from GALEX observations*

, 91191 Gif sur Yvette Cedex, France 1 INAF Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy 2 Based on GALEX observations: GI3-0087 PI R. Rampazzo 3 Department of

The mid-infrared colour–magnitude relation of early-type galaxies in the Coma cluster as measured by Spitzer-IRS*

We use 16 μm, Spitzer-Infrared Spectrograph, blue peak-up photometry of 50 early-type galaxies in the Coma cluster to define the mid-infrared colour–magnitude relation. We compare with recent simple stellar population models that include the mid-infrared emission from the extended, dusty envelopes of evolved stars. The Ks-[16] colour in these models is very sensitive to the...

Surface photometry of binary galaxies. I. A multicolour study of morphologies due to the interaction

We present the multicolour (B, V, R) surface photometry of 53 double galaxies. All the pairs belong to the catalogue of Reduzzi & Rampazzo (1995) containing objects selected according to the Karachentsev (1972) criteria. We comment on the morphological, structural and photometric characteristics of pairs and their members. Different classes of interaction induced phenomena, both...

Surface photometry of binary galaxies. I. A multicolour study of morphologies due to the interaction

We present the multicolour (B, V, R) surface photometry of 53 double galaxies. All the pairs belong to the catalogue of Reduzzi & Rampazzo (1995) containing objects selected according to the Karachentsev (1972) criteria. We comment on the morphological, structural and photometric characteristics of pairs and their members. Different classes of interaction induced phenomena, both...

The star formation history of early-type galaxies as a function of mass and environment

Using the third data release of the Sloan Digital Sky Survey (SDSS), we have rigorously defined a volume-limited sample of early-type galaxies in the redshift range 0.005 < z≤ 0.1. We have defined the density of the local environment for each galaxy using a method which takes account of the redshift bias introduced by survey boundaries if traditional methods are used. At...

The Galaxy Evolution Explorer UV emission in shell galaxies: tracing galaxy ‘rejuvenation’ episodes

We present the Galaxy Evolution Explorer (GALEX) far-ultraviolet (FUV) and near-ultraviolet (NUV) imaging of three nearby shell galaxies, namely NGC 2865, NGC 5018 and NGC 7135 located in low-density environments. The system of shells and fine structures visible in the optical is detected in the NUV image of NGC 2865 and in both NUV and FUV images of NGC 7135. The NUV image of...

Optical properties of the NGC 5328 group of galaxies⋆

We present the results of a photometric and spectroscopic study of seven members of the NGC 5328 group of galaxies, a chain of galaxies spanning over 200 kpc (H0= 70 km s−1 Mpc−1). We analyse the galaxy structure and study the emission-line properties of the group members looking for signatures of star formation and active galactic nucleus activity. We finally attempt to infer...

Two-dimensional warm gas kinematics in interacting galaxy systems

Gas reservoirs, internal or acquired, play an important role in the secular evolution of interacting galaxies, since they are able to enhance/trigger star formation episodes and, probably, feed the activity of active galactic nuclei. Using Fabry–Perot observations, we have mapped, in the Hα line, the warm (T≈ 104) gas distribution and the velocity fields of the galaxy members of...

The hot, warm and cold gas in Arp 227 – an evolving poor group

Arp 227 represents a prototypical example of an interacting mixed pair of galaxies located in a low-density environment. We investigate the gas properties of the pair in the X-ray, Hα, H i and CO bands. We also detect two additional members of the group in H i which indicates that the pair constitutes the dominant members of a loose group. The H i distribution shows a tail of gas...

Comparative study of fine structure in samples of isolated and paired early-type galaxies

L. Reduzzi 0 M. Longhettf 0 R. Rampazzo 0 0 lIstituto di Fisica Generale Applicata , Via Brera 28, 20121 Milano , Italy 2Universita degli Studi di Milano , Via Celoria 16,20133 Milano , Italy ... properties of shells, such as their geometrical (e.g. types and their relative frequency, radial R 49 150 L. Reduzzi, M. Longhetti and R. Rampazzo 1 . 2. distribution), photometrical (e.g. colours, surface

Warm gas kinematics in shell galaxies

Shells are interpreted as debris from interaction/acquisition episodes that occur in a galaxy. We present a study of the warm (T≈ 104 K) gas component in a sample of five shell galaxies belonging to the Malin & Carter compilation. Hα observations have been obtained at the ESO 3.6-m telescope equipped with a CIGALE scanning Fabry–Perot interferometer coupled with a new IPCS camera...

Star formation history of early-type galaxies in low density environments - I. Nuclear line–strength indices

This paper is the first of a series (Longhetti et al. 1997a,b) dedicated to the study of the star formation history in early-type galaxies which show fine structures and/or signatures of interaction. It presents nuclear line–strength indices for a sample composed of 21 shell galaxies, from the the Malin & Carter (1983) southern survey, and 30 members of isolated interacting pairs...

Star formation history of early-type galaxies in low density environments - II. Kinematics

a sample of shell galaxies and pair members, whose spectro{photometric data have been presented in Longhetti et al. (1997 a, Paper I). Send o print requests to: R. Rampazzo ? Based on observations

Star formation history of early-type galaxies in low density environments - II. Kinematics

a sample of shell galaxies and pair members, whose spectro{photometric data have been presented in Longhetti et al. (1997 a, Paper I). Send o print requests to: R. Rampazzo ? Based on observations