17177272
The core fundamental plane of B2 radio galaxies
Context. The photometric, structural and kinematical properties of the centers of elliptical galaxies harbour important information on the formation history of galaxies. In the case of non-active elliptical galaxies, these properties are linked in a way that surface brightness, break radius and velocity dispersion of the core lie on a fundamental plane similar to that found for their global properties. Aims. We construct the core fundamental plane (CFP) for a sizeable sample of low redshift radio galaxies and compare it with that of non-radio ellipticals. Methods. We combine data obtained from high resolution HST images with medium resolution optical spectroscopy to derive the photometric and kinematic properties of ∼40 low redshift radio galaxies. Results. We found that the CFP of radio galaxies is indistinguishable from that defined by non-radio elliptical galaxies of similar luminosity. The characteristics of the CFP of radio galaxies are also consistent (same slope) with those of the fundamental plane (FP) derived from the global properties of radio (and non-radio) elliptical galaxies. The similarity of CFP and FP for radio and non-radio ellipticals suggests that the active phase of these galaxies has minimal effects on the structure of the galaxies.
16975153
The bright galaxy population of five medium redshift clusters II. Quantitative galaxy morphology
Aims. Following the study presented in our previous paper, based on the Nordic Optical Telescope (NOT) sample, which consists of five clusters of galaxies within the redshift range 0.18 ≤ z ≤ 0.25 imaged in the central 0.5–2 Mpc in very good seeing conditions, we have studied the quantitative morphology of their bright galaxy population Methods. We analyzed the surface brightness profiles of the galaxy population in those clusters, after performing simulations in order to check the reliability of the fits. We also derived a quantitative morphological classification. Results. The structural parameters derived from these analyses are presented. We obtained that the structural parameters of E/S0 galaxies are similar to those shown by galaxies in low redshift clusters. However, the disc scales are different. In particular, the scales of the discs of galaxies in medium redshift clusters are statistically different than those located in similar galaxies in the Coma cluster. However, the scales of the discs of galaxies in medium redshift clusters are similar to nearby field galaxies. Conclusions. Our results suggest that the evolution of the disc component of galaxies in clusters is faster than in field ones. Mechanisms like galaxy harassment showing timescales of ∼1 Gyr could be responsible for this disc scale evolution. This indicates that spiral galaxies in clusters have undergone a strong evolution in the last 2.5 Gyr or that Coma is in some way anomalous.
14891588
The visible environment of galaxies with counterrotation
In this paper we present a statistical study of the environments of 49 galaxies in which there is gas- or stellar-counterrotation. The number of possible companions in the field (to apparent magnitude 22), their size and concentration were considered. All the statistical parameters were analysed by means of Kolgomorov-Smirnov tests, using a control sample of 43 galaxies without counterrotation. From our data, no significant differences between the counter-rotating and control samples appear. This is different to Seyfert or radio-loud galaxies which lie in environments with a higher density of companions. On the contrary, if a weak tendency exists, for galaxies with gas counterrotation only, it is discovered in regions of space where the large scale density of galaxies is smaller. Our results tend to disprove the hypothesis that counterrotation and polar rings derive from a recent interaction with a small satellite or a galaxy of similar size. To a first approximation, they seem to follow the idea that all galaxies are born through a merger process of smaller objects occurring very early in their life, or that they derive from a continuous, non-traumatic infall of gas that formed stars later. Whatever the special machinery is which produces counterrotation or polar rings instead of a co-planar, co-rotating distribution of gas and stars, it seems not to be connected to the present galaxy density of their environments.
18425047
The peculiar galaxy IC 1182: An ongoing merger?
Broad and narrow band images and long slit spectroscopy of IC1182 are presented. The broad band images reveal a distorted morphology with a large, heavily obscured disk-like structure and several knots in the central region. Galactic material, some of it in the form of two tails, is detected well beyond the main body of the galaxy. The second, fainter tail and several knots are reported here for the first time. The narrow band images show that the galaxy is a powerful emitter. The emission in the main lines extends all over the galaxy, with plumes and arc-like structures seen in H$\alpha$ at large distances from the center. The uncorrected H$\alpha$ flux corresponds to 3.51$\times10^{41}$ erg s$^{-1}$, 3 times that of Arp 220. The internal extinction deduced from the Balmer decrement is high all along the slit, with E$_{B-V}\approx$ 1. There are no clear signs of nuclear activity and the observed line ratios can be explained in terms of stellar photoionization. The metallicity of the gas in the two brightest central knots is low, 0.1 Z$_{\odot}$ and 0.06 Z$_{\odot}$ respectively. In the main body of the galaxy, besides the reported knots, the distribution of the ionized gas resembles that of an inclined disk about 12 kpc in size. The rotation pattern is complex and corresponds to two identifiable disk galaxies with observed rotation amplitudes of 200 \kms and 100 \kms respectively. The data presented here indicate that IC 1182 is a high luminosity starburst system, involving two systems in the process of merging, with two tidal tails emerging from the central region of the galaxy.
119325667
The scaling relations of early{type galaxies in clusters ? I. Surface photometry in seven nearby clusters
This is the first paper of a series investigating the scaling relations of early–type galaxies in clusters. Here we illustrate the multi–band imagery and the image reduction and calibration procedures relative to the whole sample of 22 clusters at $0.05 \mathrel{\raise0.35ex\hbox{$\scriptstyle <$}\kern-0.6em \lower0.40ex\hbox{{$\scriptstyle \sim$}}}z \mathrel{\raise0.35ex\hbox{$\scriptstyle <$}\kern-0.6em \lower0.40ex\hbox{{$\scriptstyle \sim$}}}0.25$. We also present detailed surface photometry of 312 early–type galaxies in 7 clusters in the first redshift bin, $z \approx0.025$–0.075. We give for each galaxy the complete set of luminosity and geometrical profiles, and a number of global, photometric and morphological parameters. They have been evaluated taking into account the effects of seeing. Internal consistency checks and comparisons with data in the literature confirm the quality of our analysis. These data, together with the spectroscopic ones presented in the second paper of the series, will provide the local calibration of the scaling relations.
1840
Cluster formation in the LMC
In this work we present preliminary results concerning the properties of about 50 clusters and associations located in a densely populated region at the Southern edge of the supershell LMC~4. The ages of the clusters and associations are derived. The cluster formation rate peaks at about 10-20 Myr ago corresponding to the age of the formation of LMC~4. Objects younger than 10 Myr are located close to CO clouds, indicating a possible trigger of the recent star formation by the interaction of the supershell with the interstellar medium. 
Isophotal analysis has been done for 50% of the clusters. A large number of objects present isophotal distortions commonly interpreted as sign of interaction. Cluster multiplets are coeval within 20 Myr, suggesting a common origin. This indicates that clusters possibly form in large groups. Our findings are in agreement with the unified view of multi-scale star formation, where a size-duration correlation is expected.
116816504
Evidence for F meson photoproduction
121146499
Prototype tests of two controlled geometry drift chambers
Abstract This report presents results on the performance of two new drift chamber geometries, which were optimized for space resolution and two-track separation. The best performance requires isochronous drift collection, low electron diffusion, and careful signal shaping. The role of the mobility of electrons and positive ions is emphasized. We tested two geometries, and at a gas pressure of 1 atm we found σ ⋍ 60–70 μ m for the single-track resolution and Δ ⋍ 600 μ m for the two-track separation.
44393741
PEP-N detector layout
We describe a possible experimental apparatus for a proposed new experiment to be carried out at an asymmetrical collider, consisting of the PEP-II Low Energy Ring (LER) and a new electron storage ring (Very Low Energy Ring, VLER) of energy 100 MeV < Ee < 800 MeV . The accessible center of mass (CM) energy will then be 1.2 GeV < √ s < 3.15 GeV . While there are many important physics measurements that are feasible at this collider, a lot of emphasis will be on R, the ratio of the hadron and muon pair cross sections, and on the determination of nucleon form factors. This paper is organized as follows: the main physics motivations will be outlined in section 2. The measurement method of R and the experimental requirements will be the subject of section 3, while the detector requirements will be discussed in section 4. Section 5 will be devoted to rates and running time. The detector layout will then be presented in section 6. The individual detector components will be briefly described in section 7 (a full description can be found in the dedicated papers in these proceedings). Finally in section 8 we will present our conclusions.
119627299
HIGH-RESOLUTION SILICON DETECTORS FOR COLLIDING BEAM PHYSICS
Abstract Resolution and linearity of the position measurement of Pisa multi-electrode silicon detectors are presented. The detectors are operated in slightly underdepleted mode and take advantage of their intrinsic resistivity for resistive charge partition between adjacent strips. 22 μm resolution is achieved with readout lines spaced 300 μm. Possible applications in colliding beam experiments for the detection of secondary vertices are discussed.
122241433
A Measurement of the Space - Like Pion Electromagnetic Form-Factor
Abstract The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/ c ) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r 2 π 〉 = 0.438±0.008 fm 2 .