15 research outputs found
LATTES: a novel detector concept for a gamma-ray experiment in the Southern hemisphere
The Large Array Telescope for Tracking Energetic Sources (LATTES), is a novel concept for an array of hybrid EAS array detectors, composed of a Resistive Plate Counter array coupled to a Water Cherenkov Detector, planned to cover gamma rays from less than 100 GeV up to 100 TeVs. This experiment, to be installed at high altitude in South America, could cover the existing gap in sensitivity between satellite and ground arrays. The low energy threshold, large duty cycle and wide field of view of LATTES makes it a powerful tool to detect transient phenomena and perform long term observations of variable sources. Moreover, given its characteristics, it would be fully complementary to the planned Cherenkov Telescope Array (CTA) as it would be able to issue alerts. In this talk, a description of its main features and capabilities, as well as results on its expected performance, and sensitivity, will be presented
The sub-TeV transient Gamma-Ray sky: challenges and opportunities
The detection of gravitational waves and neutrinos from astrophysical sources
with gamma-ray counterparts officially started the era of Multi-Messenger
Astronomy. Their transient and extreme nature implies that monitoring the VHE
sky is fundamental to investigate the non-electromagnetic signals. However, the
limited effective area of space-borne instruments prevents observations above a
few hundred GeV, while the small field of view and low duty cycle of IACTs make
them unsuited for extensive monitoring activities and prompt response to
transients. Extensive Air Shower arrays (EAS) can provide a large field of
view, a wide effective area and a very high duty cycle. Their main difficulty
is the distinction between gamma-ray and cosmic-ray initiated air showers,
especially below the TeV range. Here we present some case studies stressing the
importance that a new EAS array in the Southern Hemisphere will be able to
survey the sky from below 100 GeV up to several TeV. In the energy domain
between 100 and 400 GeV we expect the strongest electromagnetic signatures of
the acceleration of ultra-relativistic particles in sources like SNRs, blazar
jets and gamma-ray bursts, as recently proved by IACT observations. This
spectral window is also crucial to understand the Universe opacity to high
energy radiation, thus providing constraints on the cosmological parameters. We
will discuss the implications of VHE radiation on the mechanisms at work and we
will focus on the advantages resulting from the ability to monitor the energy
window lying between the domain of space-borne detectors and ground-based
facilities
Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory
The surface detector array of the Pierre Auger Observatory consists of 1600
water-Cherenkov detectors, for the study of extensive air showers (EAS)
generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy,
from the identification of candidate showers at the level of a single detector,
amongst a large background (mainly random single cosmic ray muons), up to the
selection of real events and the rejection of random coincidences. Such trigger
makes the surface detector array fully efficient for the detection of EAS with
energy above eV, for all zenith angles between 0 and
60, independently of the position of the impact point and of the mass
of the primary particle. In these range of energies and angles, the exposure of
the surface array can be determined purely on the basis of the geometrical
acceptance.Comment: 29 pages, 12 figure
Ultrahigh energy neutrinos at the Pierre Auger observatory
The observation of ultrahigh energy neutrinos (UHEνs) has become a priority in experimental astroparticle physics. UHEνs can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going ν) or in the Earth crust (Earth-skimming ν), producing air showers that can be observed with arrays of detectors at the ground. With the surface detector array of the Pierre Auger Observatory we can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). In this work we review the procedure and criteria established to search for UHEνs in the data collected with the ground array of the Pierre Auger Observatory. This includes Earth-skimming as well as downward-going neutrinos. No neutrino candidates have been found, which allows us to place competitive limits to the diffuse flux of UHEνs in the EeV range and above.P. Abreu ... K. B. Barber ... J. A. Bellido ... R. W. Clay ... M. J. Cooper ... B. R. Dawson ... T. A. Harrison ... A. E. Herve ... V. C. Holmes ... J. Sorokin ... P. Wahrlich ... B. J. Whelan ... et al
Relative growth and sexual maturity of the freshwater shrimp Palaemon pandaliformis (Crustacea, Palaemonidae) in northeastern of Brazil (Canavieiras, Bahia)
This study comprises the description of relative growth and sexual maturity of a population of Palaemon pandaliformis Stimpson, 1871 in Salsa River (Northeastern Brazil). Samples were collected monthly between September 2009 and August 2010. Females were larger, heavier, and showed a greater allometric coefficient (b) than male specimens. Only carapace length vs. pleura length in females presented a significant difference in the relative growth pattern, indicating a puberty moult. This relationship is strictly correlated to reproduction and its success rate in female shrimps. Estimated carapace length in 50% of mature females (CL50) was 4.53 mm. It was not possible to compare obtained CL50 results due to a lack of studies on this species. Comparison was based on the size of the smallest captured ovigerous female (3.81 CL mm), which is within the scope of recorded size for estuaries located in higher latitudes. This study reveals the lack of research on this genre in freshwater environments on a national and global scale
Chironomidae (Insecta: Diptera) no Estado do Rio de Janeiro, Brasil: situa\ue7\ue3o atual, lista de esp\ue9cies e novos registros
Volume: 67Start Page: 337End Page: 34
Die volkswirtschaftlichen Kosten des Naturschutzes in Berlin: oekonom. Begleitstudie zu d. Grundlagen fuer d. Artenschutzprogramm in Berlin
Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel A 164343 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman