Browsing by Autor "P. Miranda"

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ALPAQUITA Array in the ALPACA Project
(2017) K. Kawata; T. Asaba; K. Hibino; N. Hotta; M. Kataoka; Y. Katayose; C. Kato; Hironori Kojima; R. Mayta; P. Miranda
We are now proposing a new project which consists of a large air shower array (83,000 m^2) and a muon detector array (5,400 m^2) located at the altitude of 4,740 m near La Paz in Bolivia to observe 100 TeV gamma rays in the southern sky. The ALPAQUITA array is a prototype air shower array which will be constructed at the ALPACA site. This array consists of 45 scintillation counters of 1 m^2 in area each, and its effective area is approximately 8,000 m^2 (1/10 of ALPACA air shower array). In the present paper, we report on the current status and the performance of the ALPAQUITA array
Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya
(NASA Headquarters, 1985) T. Kaneko; K. Hagiwara; H. Yoshii; N. Martinić; L. Siles; P. Miranda; F. Kakimoto; Toru Obara; N. Inoue; K. Suga
Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers.
Effects of the May 10, 2024 Solar Storm on the South Atlantic Anomaly: A Case Study in Bolivia
(2025) C. A. H. Condori; R. Ticona; P. Miranda; C. A. Guerrero; E. Romero‐Hernández; E. Peréz‐Tijerina; R. Raljevic; M. Subieta-Vázquez
<title>Abstract</title> We analyzed the strongest geomagnetic storm of the past two decades, which occurred on May 10, 2024, focusing on plasma data from spacecraft, Earth's magnetic field variations recorded at the Villa Remedios Magnetic Observatory, and neutron data from the 12-NM64 monitor, both located in La Paz, Bolivia. Situated within the South Atlantic Magnetic Anomaly (SAA), this region offers a unique perspective on geomagnetic disturbances, emphasizing the relevance of localized studies. The Villa Remedios Magnetic Observatory recorded a Dst drop of -560 nT, significantly larger than the -412 nT reported by the Kyoto station, underscoring pronounced regional variations likely amplified by SAA's influence. Concurrently, the neutron monitor at Chacaltaya registered a Forbush decrease on May 10, linked to coronal mass ejections (CMEs) and solar flares that occurred on May 8. This decrease was followed by a prolonged 13-day recovery, mirroring patterns observed in the Dst index. The combined data highlight the intricate interplay between solar activity and its terrestrial impacts, revealing significant correlations among CMEs, solar wind velocity, proton and electron fluxes, and geomagnetic disturbances. What did we learn from this geomagnetic storm? The importance of considering the geographical location and magnetic environment when analyzing such phenomena.
Energetic delayed hadrons in large air showers observed at 5200m above sea level
(1985) T. Kaneko; K. Hagiwara; H. Yoshii; N. Martinić; L. Siles; P. Miranda; F. Kakimoto; I. Tsuchimoto; N. Inoue; K. Suga
Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta.
OBSERVACIÓN SIMULTÁNEA DE NEUTRONES SOLARES EN ASOCIACIÓN CON UNA FULGURACIÓN SOLAR DEL 7 DE SEPTIEMBRE DE 2005
(2007) P. Miranda; R. Bustos; O. Burgoa; D. López; Y. Matsubara
El 7 de Septiembre de 2005 a las 17:36:40 (GMT) se produjo una fulguracion solar registrada por el Telescopio de Neutrones Solares (TNS) y el Monitor de Neutrones (12NM-64) a las 17:40 (GMT), que fue verificado por el satelite GOES[1]. Se observa una correlacion del evento entre los datos del experimento de Chacaltaya y los del Observatorio Geomagnetico de Patacamaya, ambos del Instituto de Investigaciones Fisicas de la Universidad Mayor de San Andres (UMSA).
Proton penetration efficiency over a high altitude observatory in Mexico
(SciPost.org, 2023) Shoko Miyake; T. Koi; Y. Muraki; Y. Matsubara; S. Masuda; P. Miranda; T. Naito; E. Ortiz; A. Oshima; T. Sakai
In association with a large solar flare on November 7, 2004, the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt. Sierra Negra (4,600 m) in Mexico recorded very interesting events. In order to explain these events, we have performed a calculation solving the equation of motion of anti-protons inside the magnetosphere. Based on these results, the Mt. Chacaltaya event may be explained by the detection of solar neutrons, while the Mt. Sierra Negra event may be explained by the first detection of very high energy solar neutron decay protons (SNDPs) around 6 GeV.
Proton Penetration Efficiency over Sierra Negra (Mexico) and Oulu (Finland)
(2023) Y. Muraki; Shoko Miyake; T. Koi; Y. Matsubara; S. Masuda; P. Miranda; T. Naito; E. Ortiz; A. Oshima; T. Sako
On November 7, 2004, a large solar flare was observed, which had a notable impact on the solar neutron detectors located at Mt. Chacaltaya (5,250 m) in Bolivia and Mt. Sierra Negra (4,600 m) in Mexico. In addition, the neutron monitor at Oulu, Finland, recorded a 5-sigma enhancement. In order to determine the causes of these enhancements, we performed trajectory simulations ejecting anti-protons from 20 km above each location, and checked whether or not these anti-protons could reach the magnetopause (∼8𝑅E). Then, we understand that the Chacaltaya enhancement was caused by solar neutrons themselves, while the Mt. Sierra Negra event may have been produced by high-energy solar neutron decay protons (SNDPs) with energies ≥ 6 GeV. Based on our anti- proton trajectory analysis, we suggest that the enhancement at Oulu may also have been produced by solar neutron decay protons with energies around ≥ 200 MeV. During this flare, protons were accelerated up to 10 GeV within one minute, leading to the production of SNDPs.
Search for 100 TeV gamma-rays from SN 1987 A
(Springer Nature, 1990) C. Castagnoli; C. Morello; G. Navarra; L. Periale; P. Vallania; J. A. Chinellato; M. de Castro Souza; A. Turtelli; P. Miranda; A. Velarde
Simultaneous observation at sea level and at 5200 m.a.s.l. of high energy particles in the South Atlantic Anomaly
(Elsevier BV, 2010) C. R. A. Augusto; C. E. Navia; K. H. Tsui; H. Shigueoka; P. Miranda; R. Ticona; A. Velarde; O. Saavedra
Simultaneous Observation of Solar Neutrons from the International Space Station and High Mountain Observatories in Association with a Flare on July 8, 2014
(Springer Science+Business Media, 2016) Y. Muraki; D. Lopez; K. Koga; F. Kakimoto; T. Goka; L. X. González; S. Masuda; Y. Matsubara; H. Matsumoto; P. Miranda
Solar Neutron Event in Association with a Large Solar Flare on 2000 November 24
(IOP Publishing, 2003) K. Watanabe; Y. Muraki; Y. Matsubara; Kazuaki Murakami; T. Sako; H. Tsuchiya; S. Masuda; M. Yoshimori; N. Ohmori; P. Miranda
Solar neutrons have been detected using the neutron monitor located at Mt. Chacaltaya, Bolivia, in association with a large solar flare on November 24, 2000. This is the first detection of solar neutrons by the neutron monitor that have been reported so far in solar cycle 23. The statistical significance of the detection is 5.5 sigma. In this flare, the intense emission of hard X-rays and gamma-rays has been observed by the Yohkoh Hard X-ray Telescope (HXT) and Gamma Ray Spectrometer (GRS), respectively. The production time of solar neutrons is better correlated with those of hard X-rays and gamma-rays than with the production time of soft X-rays. The observations of the solar neutrons on the ground have been limited to solar flares with soft X-ray class greater than X8 in former solar cycles. In this cycle, however, neutrons were detected associated with an X2.3 solar flare on November 24, 2000. This is the first report of the detection of solar neutrons on the ground associated with a solar flare with its X-ray class smaller than X8.
Solar neutron events in association with large solar flares in November 2003
(Elsevier BV, 2005) K. Watanabe; Y. Muraki; Y. Matsubara; Kazuaki Murakami; T. Sako; P. Miranda; R. Ticona; A. Velarde; F. Kakimoto; S. Ogio
VARIATIONS OF THE MUON FLUX AT SEA LEVEL ASSOCIATED WITH INTERPLANETARY ICMEs AND COROTATING INTERACTION REGIONS
(IOP Publishing, 2012) C. R. A. Augusto; V. Kopenkin; C. E. Navia; K. H. Tsui; H. Shigueoka; A. C. Fauth; E. Kemp; E. J. Tonelli Manganote; M. A. Leigui de Oliveira; P. Miranda
Americanae nace como un proyecto conjunto que surge dentro de la Red Europea de Información y Documentación sobre América Latina (REDIAL), y que ha afrontado la Biblioteca de la Agencia Española de Cooperación Internacional para el Desarrollo (AECID). Esta nueva biblioteca virtual hace más accesibles los libros digitales de tema americanista a los investigadores y usuarios interesados de cualquier parte del mundo.