123641202
Seismic Attenuation System (SAS) in the Kamioka Mine
120833712
Subterranean ground motion studies for the Einstein Telescope
Seismic motion limits the low-frequency sensitivity of ground-based gravitational wave detectors. A conceptual design study into the feasibility of a future-generation gravitational wave observatory, coined the Einstein Telescope, has been completed. As part of this design phase, we performed a ground motion study to determine the seismic noise characteristics at various sites across the globe. This investigation focused on underground sites and encompassed a variety of geologies, including clay, salt, and hard rock, at 15 locations in nine European countries, the USA, and Japan. In addition, we analyzed data from the Virtual European Broadband Seismograph Network to characterize European seismic motion. We show that, in the region of interest for future-generation gravitational wave detectors (1–10 Hz), seismic motion is dominated by activity from anthropogenic sources. A number of sites were found that exhibited a reduction in seismic power of several orders of magnitude with respect to current detector sites, thus making it possible to set requirements for the Einstein Telescope seismic noise environment.
7488810
A study of the H2O maser emission from R Cas
We describe the monitoring program we have been carrying out during the past 10 years on a sample of late-type stars, with the Medicina 32-m and Effelsberg 100-m antennas. We discuss the observations on the Mira-variable R Cas in some detail.
119247622
High CO depletion in southern infrared dark clouds
Infrared dark high-mass clumps are among the most promising objects to study the initial conditions of the formation process of high-mass stars and rich stellar clusters. In this work, we have observed the (3–2) rotational transition of C18O with the Atacama Pathfinder EXperiment telescope and the (1,1) and (2,2) inversion transitions of NH3 with the Australia Telescope Compact Array in 21 infrared dark clouds already mapped in the 1.2-mm continuum, with the aim of measuring basic chemical and physical parameters such as the CO depletion factor (fD), the gas kinetic temperature and the gas mass. In particular, the C18O (3–2) line allows us to derive fD in gas at densities higher (and hence potentially more depleted) than that traced by the (1–0) and (2–1) lines, typically used in previous works. We have detected NH3 and C18O in all targets. The clumps have a median mass of ∼244 M⊙, are gravitationally bound, have an average kinetic temperature of 17 K and possess mass, H2 column and surface densities consistent with being potentially the birthplace of high-mass stars. We have measured fD in between 5 and 78, with a mean value of 32 and a median of 29. These values are, to our knowledge, larger than the typical CO depletion factors measured towards infrared dark clouds and high-mass dense cores, and are comparable to or larger than the values measured in low-mass pre-stellar cores close to the onset of the gravitational collapse. This result suggests that the earliest phases of the high-mass star and stellar cluster formation process are characterized by fD larger than in low-mass pre-stellar cores. On the other hand, fD does not seem to be correlated to any other physical parameter, except for a faint anticorrelation with the gas kinetic temperature. 13 out of 21 clumps are undetected in the 24-m Spitzer images, and have slightly lower kinetic temperatures, masses and H2 column densities with respect to the eight Spitzer-bright sources. This could indicate that the Spitzer-dark clumps are either less evolved or are going to form less massive objects.