110897779
The E835 scintillating fiber tracking detector
This paper describes the scintillating fiber tracking detector designed and built for the Fermilab experiment E835. This detector uses Visible Light Photon Counters (VLPC) readout system and is in use at the p ¯ accumulator ring at Fermilab. A description of the components of the detector and preliminary results of its performances are given.
108986863
Performance measurements of histe-V VLPC photon detectors for E835 at FNAL
A set of 144 VLPC chips has been used by experiment E835 at FNAL for the readout of its scintillating fiber detector. During the data taking, the fibers have been exposed to rates up to 2.5×104 mips/sec, corresponding to 3.5×106 photons/sec on each VLPC pixel surface. This paper reports about a study on rate dependence of gain and quantum efficiency throughout the run, as well as VLPC failure statistics during operation. No significant aging effects are observed. A review about the overall system performance is given.
123064237
The charged trigger of the experiment E835 at Fermilab
Abstract Fermilab experiment E835 studies the charmonium states primarily through their electromagnetic decays. A kinematical charged trigger has been designed to select the electromagnetic final states e + e − and e + e − X and the hadronic decay c c → φφ →4 K ± . A detailed description of the charged trigger is presented here. The design, its implementation and the performances are given.
125331327
The Fermilab anti-p accumulator ring for the charmonium experiment
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.
119936495
Hadronic Physics with Antiprotons at FAIR
The physics program of the future FAIR facility covers a wide range of topics that address central issues of strong interactions and QCD. The antiproton beam of unprecedented quality in the momentum range from 1 GeV/c to 15 GeV/c will allow to make high precision, high statistics measurements, from charmonium spectroscopy to the search for exotic hadrons and the study of nucleon structure, from the study of in-medium modifications of hadron masses to the physics of hypernuclei. These topics form the scientific program of the PANDA experiment. In addition to that the possibility to polarize antiprotons will provide the possibility to perform new, unique measurements of single- and double-spin observables, which are part of the experimental program of PAX.
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.
10342067
THE VISIBLE ENVIRONMENT OF POLAR RING GALAXIES
A statistical study of the environment around Polar Ring Galaxies is presented. Two kinds of search are performed: 1) a study of the concentration and diameters of all the objects surrounding the Polar Rings, within a search eld 5 times the ring diameter. New magnitudes for polar ring galaxies are pre- sented. 2) a search, in a wider eld, for galaxies of similar size that may have encountered the polar ring host galaxy in a time of the order of 1 Gyr. Differently from the results of similar searches in the elds of active galaxies, the environment of the Polar Ring Galaxies seems to be similar to that of normal galax- ies. This result may give support to the models suggesting long timesforformationandevolutionoftherings.Iftheringsareold (and stable or in equilibrium), no traces of the past interaction are expected in their surroundings. In addition, the formation of massive polar rings, too big to derive from the ingestion of a present-day dwarf galaxy, may be easily placed in epochs with a higher number of gas-rich galaxies.
17610175
Are truncated stellar disks linked to the molecular gas density
We know that the slope of the radial, stellar light distribution in galaxies is well described by an exponential decline and this distribution is often truncated at a break radius ($R_{br}$). We don't have a clear understanding for the origin of these outer truncations and several hypotheses have been proposed to explain them. We want to test the various theories with direct observations of the cold molecular gas for a few truncated galaxies in comparison with the non-truncated ones. The answer to the existence of a possible link between truncated stellar disks and the molecular gas density cannot be obtained from CO maps in the literature, because so far there are no galaxies with a clear truncation observed in CO at high resolution.
119290984
ON THE CONNECTION BETWEEN SHAPE AND STELLAR POPULATION IN EARLY-TYPE GALAXIES
We report on the discovery of a relation between the stellar mass M* of early-type galaxies (hereafter ETGs), their shape, as parameterized by the Sersic index n, and their stellar mass-to-light ratio M*/L. In a three-dimensional log space defined by these variables, the ETGs populate a plane surface with small scatter. This relation tells us that galaxy shape and stellar population are not independent physical variables, a result that must be accounted for by theories of galaxy formation and evolution.
55802943
The shapes of BCGs and normal ellipticals in nearby clusters
We compare the apparent axial ratio distributions of the brightest cluster galaxies (BCGs) and normal ellipticals (Es) in our sample of 75 galaxy clusters from the WIde-field Nearby Galaxy-cluster Survey (WINGS). Most BCGs in our clusters (69 per cent) are classified as cD galaxies. The sample of cDs has been completed by 14 additional cDs (non-BCGs) we found in our clusters. We deproject the apparent axial ratio distributions of Es, BCGs and cDs using a bivariate version of the Lucy rectification algorithm, whose results are supported by an independent Monte Carlo technique. Finally, we compare the intrinsic shape distribution of BCGs to the corresponding shape distribution of the central part of cluster-sized dark matter haloes extracted from the GIF2 Lambda cold dark matter (ΛCDM) N-body simulations (Gao et al.). 
 
 
 
We find that (i) Es have triaxial shape, the triaxiality sharing almost evenly the intrinsic axial ratio parameter space, with a weak preference for prolateness and (ii) the BCGs have triaxial shape as well. However, their tendency towards prolateness is much stronger than in the case of Es. Such a strong prolateness appears entirely due to the sizeable (dominant) component of cDs inside the WINGS sample of BCGs. In fact, while the ‘normal’ (non-cD) BCGs do not differ from Es, as far as the shape distribution is concerned, the axial ratio distribution of BCG_cD galaxies is found to support quite prolate shapes; (iii) our result turns out to be strongly at variance with the only similar previous analysis by Ryden, Lauer & Postman (RLP93), where BCGs and Es were found to share the same axial ratio distribution; (iv) our data suggest that the above discrepancy is mainly caused by the different criteria that RLP93 and ourselves use to select the cluster samples, coupled with a preference of cDs to reside in powerful X-ray-emitting clusters; (v) the GIF2 N-body results suggest that the prolateness of the BCGs (in particular the cDs) could reflect the shape of the associated dark matter haloes.