Infrastructure for Detector Research and Development towards the International Linear Collider

The EUDET-project was launched to create an infrastructure for developing and testing new and advanced detector technologies to be used at a future linear collider. The aim was to make possible experimentation and analysis of data for institutes, which otherwise could not be realized due to lack of resources. The infrastructure comprised an analysis and software network, and instrumentation infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture

Transverse and longitudinal correlation functions in the Intergalactic Medium from 32 close pairs of high-redshift quasars

We present the transverse flux correlation function of the Lyman-alpha forest in quasar absorption spectra at z~2.1 from VLT-FORS and VLT-UVES observations of a total of 32 pairs of quasars; 26 pairs with separations in the range 0.6<theta<4 arcmin and 6 pairs with 4<theta<10 arcmin. Correlation is detected at the 3sigma level up to separations of the order of ~4 arcmin (or ~4.4 h^{-1} Mpc comoving at z=2.1 for Omega_{m}=0.3 and Omega_{Lambda}=0.7). We have, furthermore, measured the longitudinal correlation function at a somewhat higher mean redshift (z=2.39) from 20 lines of sight observed with high spectral resolution and high signal-to-noise ratio with VLT-UVES. We compare the observed transverse and longitudinal correlation functions to that obtained from numerical simulations and illustrate the effect of spectral resolution, thermal broadening and peculiar motions. The shape and correlation length of the correlation functions are in good agreement with those expected from absorption by the filamentary and sheet-like structures in the photoionized warm intergalactic medium predicted in CDM-like models for structures formation. Using a sample of 139 C_{iv} systems detected along the lines of sight toward the pairs of quasars we also investigate the transverse correlation of metals on the same scales. The observed transverse correlation function of intervening C_{iv} absorption systems is consistent with that of a randomly distributed population of absorbers. This is likely due to the small number of pairs with separation less than 2 arcmin. We detect, however, a significant overdensity of systems in the sightlines towards the quartet Q0103-294A&B, Q0102-2931 and Q0102-293 which extends over the redshift range 1.5<z<2.2 and an angular scale larger than 10 arcmin.Comment: accepted for publication in MNRAS, Appendix B and C will be published online onl

ANTARES: the first undersea neutrino telescope

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given

The correlation of the Lyman-alpha forest and metals in close pairs of hight-redshift quasars

We derive the transverse flux correlation function in the Lyman-alpha forest at z~2.1 from VLT-FORS observations of a total of 32 pairs of quasars. The shape and correlation length of the transverse correlation function are in good agreement with the paradigm of intergalactic medium predicted in CDM-like models for structures formation. Using a sample of 139 Civ systems detected along the lines of sight toward the pairs of quasars we investigate the transverse correlation of metals on the same scales. We find that the correlation function is consistent with that of a randomly distributed population of Civ systems. However, we detect an important overdensity of systems in front of a quartet

The correlation of the Lyman-alpha forest and metals in close pairs of hight-redshift quasars

We derive the transverse flux correlation function in the Lyman-alpha forest at z~2.1 from VLT-FORS observations of a total of 32 pairs of quasars. The shape and correlation length of the transverse correlation function are in good agreement with the paradigm of intergalactic medium predicted in CDM-like models for structures formation. Using a sample of 139 Civ systems detected along the lines of sight toward the pairs of quasars we investigate the transverse correlation of metals on the same scales. We find that the correlation function is consistent with that of a randomly distributed population of Civ systems. However, we detect an important overdensity of systems in front of a quartet

Transverse and Longitudinal Correlation Functions in the Intergalactic Medium

International audienceThe Intergalactic Medium can be studied using the imprint left in the spectra of background quasars, the so-called Lyman-α forest. The correlations between absorption features observed along the lines of sight to the quasars have been studied to derive information on the clustering properties of the IGM structures. Very few observations have been performed so far of the correlation of the absorption along two different lines of sight separated by a few arc-minutes in the sky. The comparison of the correlation functions along the line of sight (longitudinal direction on a velocity scale) and in the perpendicular direction (on an angular scale) can be used to constrain the geometry of the Universe. We have recently completed a study of the transverse and longitudinal flux correlation functions of the Lyman-α forest in quasar absorption spectra at z ~ 2.1 from VLT-FORS and VLT-UVES observations of a total of 32 pairs of quasars with separations in the range 0.6 < θ < 10 arcmin and found a correlation signal up to 3-5 arcmin

Why do we flush gas in gaseous detectors?

International audienceThe effects and the origin of the gas degradation in a gaseous detector-based tracker are investigated. The study focused on the so-called T2K gas, which turned out to be highly sensitive to pollutants. In particular the H$_2$O and O$_2$ concentrations were monitored online in different conditions to establish their influence on the gain of the detectors. This pollution was first mitigated by a recirculating and accelerating gas system with the use of a turbine and different absorbers. Further measurements revealed that this pollution originates from a continuous permeation process through the different materials of the gas circuit. In particular, polyurethane-based gas pipes or polyester materials largely increase the level of humidity. As a direct consequence of this work, the gas autonomy of the muon telescopes currently deployed inside the Khufu’s pyramid have been dramatically improved

Resurgence of minority and autochthonous grapevine varieties in South America: a review of their oenological potential

In contrast with the general trend of producing wine from the most famous grapevine varieties, associated with the French paradigm, such as Cabernet‐Sauvignon, Merlot, Pinot Noir, Syrah, Sauvignon Blanc, and Chardonnay, there is a tendency to revalorize and preserve minority or autochthonous grapevine varieties worldwide. The South American wine region, where most of the varieties derived from varieties brought after European colonization, is not exempt from this. This has allowed new wines to be provided with distinctive identities that are markedly different from the current homogeneous wine production. Moreover, varietal homogenization increases vineyard genetic vulnerability in relation to the emergence of grapevine diseases, to which the commonly cultivated varieties are not resistant. This review summarizes the oenological potential of minority or autochthonous grapevine varieties cultivated within the South American wine region, focusing on Argentina, Chile, and Bolivia.G. G.‐G. is grateful for the financial support given by CONICYT PFCHA/Doctorado Becas Chile/2016 – 72170532.Peer reviewe

Simulations of BAO reconstruction with a quasar Ly-

Context. The imprint of baryonic acoustic oscillations (BAO) on the matter power spectrum can be constrained using the neutral hydrogen density in the intergalactic medium (IGM) as a tracer of the matter density. One of the goals of the baryon oscillation spectroscopic survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III) is to derive the Hubble expansion rate and the angular scale from the BAO signal in the IGM. To this aim, the Lyman-α forest about 150 000 quasars will be observed in the redshift range 2.2 < z < 3.5 and over  ~10   000 deg2. Aims. We simulated the BOSS QSO survey to estimate the statistical accuracy on the BAO scale determination provided by such a large-scale survey. In particular, we discuss the effect of the poorly constrained estimate of the quasar’s unabsorbed intrinsic spectrum. Methods. The volume of current N-body simulations being too small for such studies, we resorted to Gaussian random field (GRF) simulations. We validated the use of GRFs by comparing the output of GRF simulations with that of the Horizon