389 research outputs found
Collection of Minima of Eclipsing Binaries, part III.
We present CCD times of minima for selected eclipsing binaries,
mainly parts of the multiple systems
The first study of 54 new eccentric eclipsing binaries in our Galaxy
We present an analysis of the apsidal motion and light curve parameters of 54 galactic Algol-type binaries never before studied. This is the first analysis of such a large sample of eccentric eclipsing binaries in our Galaxy, and has enabled us to identify several systems that are worthy of further study. Bringing together data from various databases and surveys, supplemented with new observations, we have been able to trace the long-term evolution of the eccentric orbit over durations extending back up to several decades. Our present study explores a rather different sample of stars to those presented in the previously published catalogue of eccentric eclipsing binaries by Bulut & Demircan (2007), sampling to fainter magnitudes, covering later spectral types, sensitive to different orbital periods with more than 50% of our systems having periods longer than 6 days. The typical apsidal motion in the sample is rather slow (mostly of order of centuries long), although in some cases this is less than 50 years. All of the systems, except one, have eccentricities less than 0.5, with an average value of 0.23. Several of the stars also show evidence for additional period variability. In particular we can identify three systems in the sample, HD 44093, V611 Pup, and HD 313631, which likely represent relativistic apsidal rotators
The SST-1M project for the Cherenkov Telescope Array
The SST-1M project, run by a Consortium of institutes from Czech Republic, Poland and Switzerland, has been proposed as a solution for implementing the small-size telescope array of the southern site of the Cherenkov Telescope Array. The technology is a pathfinder for efficient production of cost-effective imaging air Cherenkov telescopes. We report on the main system features and recent upgrades, the performances validation and the operation campaign carried out in 2018
Design, upgrade and characterization of the silicon photomultiplier front-end for the AMIGA detector at the Pierre Auger Observatory
AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the
Pierre Auger Observatory to complement the study of ultra-high-energy cosmic
rays (UHECR) by measuring the muon content of extensive air showers (EAS). It
consists of an array of 61 water Cherenkov detectors on a denser spacing in
combination with underground scintillation detectors used for muon density
measurement. Each detector is composed of three scintillation modules, with 10
m detection area per module, buried at 2.3 m depth, resulting in a total
detection area of 30 m. Silicon photomultiplier sensors (SiPM) measure the
amount of scintillation light generated by charged particles traversing the
modules. In this paper, the design of the front-end electronics to process the
signals of those SiPMs and test results from the laboratory and from the Pierre
Auger Observatory are described. Compared to our previous prototype, the new
electronics shows a higher performance, higher efficiency and lower power
consumption, and it has a new acquisition system with increased dynamic range
that allows measurements closer to the shower core. The new acquisition system
is based on the measurement of the total charge signal that the muonic
component of the cosmic ray shower generates in the detector.Comment: 40 pages, 33 figure
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