0000000000345187
AUTHOR
Maria Concetta Maccarone
showing 12 related works from this author
Ultra-High Energy Neutrinos at the Pierre Auger Observatory
2013
The observation of ultrahigh energy neutrinos (UHE nu s) has become a priority in experimental astroparticle physics. UHE nu s can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going nu) or in the Earth crust (Earth-skimming nu), 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 …
The Lateral Trigger Probability function for the Ultra-High Energy Cosmic Ray Showers detected by the Pierre Auger Observatory
2011
In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 1017 and 1019 eV and zenith angles up to 65. A parametrization combining a step function with an exponenti…
Identifying clouds over the Pierre Auger Observatory using infrared satellite data
2013
We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud. identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km(2) of the Pierre Auger Observatory twice per hour with a spatial resolution of similar to 2.4 km by similar to 5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories. (C) 2013 Elsevier B.V. All rights reserved.
Suitability of a content-based retrieval method in astronomical image databases
1996
Abstract Indexing and retrieval methods based on the image content are required to effectively use information from large repositories of digital images. Usually, the way to search for data and images in astronomical archives is via textual queries expressed in terms of constraints on observation parameters. In this paper we present a method for automatic extraction of images by using shape descriptions based on local symmetry. The proposed indexing methodology has been developed and tested inside JACOB, a prototypal system for content-based video database querying.
A Targeted Search for Point Sources of EeV Neutrons
2014
A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine “target sets”, in addition to the search for a neutron flux from the Galactic Center or from the Galactic Plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. …
The EUSO Data Simulation and Analysis Tree
2004
The "Extreme Universe Space Observatory - EUSO" is the first Space mission devoted to the exploration of the outermost bounds of the Universe through the investigation of the Extremely-High Energy Cosmic Rays, EECR, using the Earth atmosphere as a giant detector. The objective is to obtain a detailed description of the Cosmic Ray spectrum beyond 5×1019 eV together with a map of the arrival directions. EUSO will detect EECR looking at the streak of fluorescence light produced when such a particle interacts with the atmosphere. The signal will be detected after its propagation upward from the dark Earth atmosphere to the EUSO telescope accommodated, as external payload, on the International S…
Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory.
2012
The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna s…
The exposure of the hybrid detector of the Pierre Auger Observatory
2010
The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The ‘‘hybrid” detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data coll…
Fusion of experimental data
1997
Abstract The integration of information from various sensory systems is one of the most difficult challenges in understanding both perception and cognition. For example, the problem of auditory-visual integration is a correspondence problem between perceived auditory and visual scenes. Two main questions arise when designing data analysis systems: what is the useful information to be integrated?, and what are the integration rules? The problem of integrating information becomes relevant whenever: (a) the same kind of data are detected by spatially distributed sensors; (b) heterogeneous data are detected by different sensors; (c) heterogeneous distributed data are involved. General problems …
PDB: A pictorial database oriented to data analysis
1993
The paper describes a new pictorial database oriented to image analysis, implemented inside the MIDAS data analysis system. Pictorial databases need expressive data structures in order to represent a wide class of information from the numerical to the visual. The model of the database is relational; however, a full normalization is not achievable, owing to the complexity of the visual information. The paper reports the general design and notes on the software implementation. Preliminary experiments show the performance of the pictorial database. Copyright © 1993 John Wiley & Sons, Ltd
Description of atmospheric conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)
2012
Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargüe and averaged monthly models, the utility of the GDAS data is shown.
Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory
2013
We derive lower bounds on the density of sources of ultra-high energy cosmic rays from the lack of significant clustering in the arrival directions of the highest energy events detected at the Pierre Auger Observatory. The density of uniformly distributed sources of equal intrinsic intensity was found to be larger than similar to (0.06 – 5) x 10(-4) Mpc(-3) at 95% CL, depending on the magnitude of the magnetic defections. Similar bounds, in the range (0.2 – 7) x 10(-4) Mpc(-3), were obtained for sources following the local matter distribution.