119437358
Construction and performance of two multicell Cherenkov counters used in FRAMM-NA1 spectrometer
Abstract Two small dimension multicell Cherenkov counters have been built for FRAMM-NA1 multiparticle spectrometer to identify pions and kaons in the momentum range between 5 and 22 GeV/c. The performances achieved and the construction details are reported.
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
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.
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.
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.
73623447
WINGS-SPE Spectroscopy in the WIde-field Nearby Galaxy-cluster Survey
Aims. We present the results from a comprehensive spectroscopic survey of the WINGS (Wide-field Nearby Galaxy-cluster Survey) clusters, a program called WINGS-SPE. The WINGS-SPE sample consists of 48 clusters, 22 of which are in the southern sky and 26 in the north. The main goals of this spectroscopic survey are: (1) to study the dynamics and kinematics of the WINGS clusters and their constituent galaxies, (2) to explore the link between the spectral properties and the morphological evolution in different density environments and across a wide range of cluster X-ray luminosities and optical properties. Methods. Using multi-object fiber-fed spectrographs, we observed our sample of WINGS cluster galaxies at an intermediate resolution of 6-9 A and, using a cross-correlation technique, we measured redshifts with a mean accuracy of ∼45 km s -1 . Results. We present redshift measurements for 6137 galaxies and their first analyses. Details of the spectroscopic observations are reported. The WINGS-SPE has ∼30% overlap with previously published data sets, allowing us both to perform a complete comparison with the literature and to extend the catalogs. Conclusions. Using our redshifts, we calculate the velocity dispersion for all the clusters in the WINGS-SPE sample. We almost triple the number of member galaxies known in each cluster with respect to previous works. We also investigate the X-ray luminosity vs. velocity dispersion relation for our WINGS-SPE clusters, and find it to be consistent with the form L x ∝ σ 4 v .
116954302
Molecular Gas and Star Formation in M81
We present IRAM 30m observations of the central 1.6 kpc of the spiral M81 galaxy. The molecular gas appears weak and with an unusual excitation physics. We discuss a possible link between low CO emission and weak FUV surface brightness.
118665124
The innermost region of the NGC 1023 Group: Insight into its evolution
The NGC 1023 group is one of the most studied nearby groups. We want to give an insight into the evolution of its innermost region by means of ultraviolet observations and proper models. We used the FUV and NUV GALEX archival data as well as a large set of SPH simulations with chemo-photometric implementation. From the UV observations we found that several, already known, dwarf galaxies very close to NGC 1023 are also detected in UV and two more objects (with no optical counterpart) can be added to the group. Using these data we construct exhaustive models to account for their formation. We find that the whole SED of NGC 1023 and its global properties are well matched by a simulation which provides a minor merger with a companion system 5 times less massive. The strong interaction phase started 7.7Gyr ago and the final merger 1.8Gyr ago.
118368961
Non-minimally coupled dark matter: effective pressure and structure formation
We propose a phenomenological model in which a non-minimal coupling between gravity and dark matter is present in order to address some of the apparent small scales issues of ΛCDM model. When described in a frame in which gravity dynamics is given by the standard Einstein-Hilbert action, the non-minimal coupling translates into an effective pressure for the dark matter component. We consider some phenomenological examples and describe both background and linear perturbations. We show that the presence of an effective pressure may lead these scenarios to differ from ΛCDM at the scales where the non-minimal coupling (and therefore the pressure) is active. In particular two effects are present: a pressure term for the dark matter component that is able to reduce the growth of structures at galactic scales, possibly reconciling simulations and observations; an effective interaction term between dark matter and baryons that could explain observed correlations between the two components of the cosmic fluid within Tully-Fisher analysis.
51826499
The red-sequence of 72 WINGS local galaxy clusters
The Niels Bohr Institute, Juliane Maries Vej 30, 2100 Copenhagen, DenmarkSeptember 20, 2011ABSTRACTWe study the color-magnitude red sequence and blue fractionof 72 X-ray selected galaxy clusters atz = 0.04−0.07 from the WINGSsurvey, searching for correlations between the characteristics of the red sequence and the environment. We consider the slope andscatter of the red sequence, the number ratio of red luminous-to-faint galaxies, the blue fraction and the fractions of ellipticals, S0sand spirals that compose the red sequence. None of these quantities correlate with the cluster velocity dispersion, X-ray luminosity,number of cluster substructures, BCG prevalence over next brightest galaxies and spatial concentration of ellipticals. Instead, theproperties of the red sequence depend strongly on local galaxy density. Higher density regions have a lower RS scatter, a higherluminous-to-faint ratio, a lower blue fraction, and a lowerspiral fraction on the RS. Our results highlight the prominent eﬀect of thelocal density in setting the epoch when galaxies become passive and join the red sequence, as opposed to the mass of the galaxy hoststructure.Key words. Surveys – Galaxies : Clusters : General – Galaxies: evolutio n – Galaxies: star formation – Galaxies: structure