3-11 July 2007
Merida, Mexico
Mexico/General timezone
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HE 1.4.A

Place

Location: Merida, Mexico
Room: Yucatan II+III+IV (Fiesta Americana)
Date: from 4 Jul 08:30 to 7 Jul 13:30

Timetable | Contribution List

Displaying 26 contributions out of 26
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
Ultra High Energy Cosmic Rays (UHECRs) have an energy many times greater than that of particles accelerated in colliders. The Extended Air Showers (EAS) resulting from their interaction in the atmosphere give us the opportunity to study not only Cosmic Rays but also these extremely energetic cascades. A method to calculate the Average Longitudinal Shower profile has been applied to the Hig ... More
Presented by Mr. Gareth HUGHES on 4/7/2007 at 14:42
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
There are some prerequisites to possible success in searching for small-scale anisotropy of cosmic ray arrival directions at the highest energies. Recent claims of autocorrelations in the data of giant extensive air shower (EAS) arrays and presumable correlations between BL Lacertae and ultra-high energy cosmic rays (UHECRs) incite to sift the Yakutsk array data. Present analysis is based ... More
Presented by Dr. Anatoly IVANOV on 7/7/2007 at 18:05
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
A key step towards the understanding of the origin of ultra-high energy cosmic rays is their mass composition. Primary photons and neutrinos produce markedly different showers from nuclei, while showers of nuclear species are not easy to distinguish. To maximise the discrimination with the Pierre Auger Observatory ideally all mass-sensitive observables should be combined, but the 10% duty cy ... More
on 4/7/2007 at 17:05
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The High Resolution Fly's Eye (HiRes) fluorescence detectors have been collecting extensive air shower (EAS) data for more than 6 years . The obtained statistics allows us to more precisely estimate the mass composition of the ultra high energy cosmic rays (UHECR). In this study we summarize the stereo shower parameters measurements, especially X_{max} measurements. The sensitivity limit ... More
Presented by Yulia FEDOROVA on 4/7/2007 at 13:54
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
Extensive air showers of cosmic rays ultra-high energy without muon component registered by the Yakutsk array have been analysed. Among them we found some clusters and these clusters correlate with pulsars. The problem of origin showers without muons and the chemical composition of cosmic rays are discussed.
Presented by Dr. Alexei MIKHAILOV on 7/7/2007 at 18:17
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
When high-energy cosmic rays impinge on a dense dielectric medium, radio waves are produced through the Askaryan effect. At wavelengths comparable to the typical longitudinal size of showers produced by Ultra-High Energy cosmic rays or neutrinos, radio signals are an extremely efficient way to detect these particles [1]. These can be detected using the Westerbork Synthesis Radio Telescope (WS ... More
Presented by Olaf SCHOLTEN on 7/7/2007 at 17:53
Type: Oral Session: HE 1.4.A
Track: HE.2.3
Data from the High Resolution Fly's Eye detector that measures cosmic rays with the fluorescence technique is used to set limits on the flux of tau neutrinos in the energy range from 10^17 to 10^21 eV. This energy range is particularly interesting as we expect a guaranteed flux of cosmogenic neutrinos from the GZK mechanism.
Presented by Prof. Kai MARTENS on 4/7/2007 at 14:06
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
We present results on the ultra-high energy cosmic ray spectrum as measued by the High Resolution Fly's Eye Experiment. The spectrum is analyzed in two different ways: monocular reconstruction and stereo reconstruction. The monocular spectrum has the highest statistics while the stereo spectrum has the best resolution.The monocular spectrum has a threshold of .1 EeV while the stereo spectrum' ... More
Presented by Prof. Pierre SOKOLSKY on 4/7/2007 at 13:42
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
A key feature of the Pierre Auger Observatory is its hybrid design, in which ultra high energy cosmic rays are detected simultaneously by fluorescence telescopes and a ground array. The two techniques see air showers in complementary ways, providing important crosschecks and measurement redundancy. Much of the hybrid capability stems from the accurate geometrical reconstruction it achieves, w ... More
Presented by Dr. Bruce DAWSON on 4/7/2007 at 15:30
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
At the southern site of the Pierre Auger Observatory, which is close to completion, an exposure that significantly exceeds the largest forerunner experiments has already been accumulated. We report a measurement of the cosmic ray energy spectrum based on the high statistics collected by the surface detector. The methods developed to determine the spectrum from reconstructed observables are des ... More
Presented by Dr. Markus ROTH on 4/7/2007 at 16:06
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
We report on the cosmic ray spectrum obtained using the inclined events detected with the Pierre Auger Observatory. Showers with zenith angles between 60$^\circ$ and 80$^\circ$ recorded in the period between January 1st, 2004 and December 31st, 2006 are analysed. Showers are first reconstructed in arrival direction and then fitted to density maps of the muon numbers obtained from $10^{19}$eV s ... More
Presented by Mrs. Pedro FACAL on 4/7/2007 at 16:18
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
Three years of data collected with the fluorescence detector in coincidence with at least one station of the surface detector array ('hybrid data') are used to measure the flux and energy spectrum of cosmic rays above about 10^{18}eV. The hybrid measurement extends the spectrum measured with the surface detector data alone towards lower energies, and provides a cross-check in the overlap regio ... More
Presented by Dr. Lorenzo PERRONE on 4/7/2007 at 16:30
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The HiRes Experiment has observed the GZK Cutoff. We will present power law fits to the latest HiRes monocular spectra, and use the results of these fits to argue that the GZK Cutoff has been definitively observed in that dataset. We will also present fits to a uniform sorce density model.
Presented by Prof. Douglas BERGMAN on 4/7/2007 at 13:30
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Telescope Array (TA) experiment is an array of surface detectors surrounded by three stations of fluorescence telescopes in Utah, USA, to investigate the origin of the highest energy cosmic rays of energy beyond 10^ {20}eV. We deployed about 500 plastic scintillation counters on a grid with 1.2 km spacing as a surface array by March 2007. Each surface detector is outfitted with double ... More
Presented by Dr. Hiroyuki SAGAWA on 7/7/2007 at 17:17
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The reconstruction of extensive air showers (arrival direction, core position and energy estimation) by the surface detector (SD) of the Pierre Auger Observatory is discussed together with the corresponding accuracy. We determine the angular reconstruction accuracy as a function of the station multiplicity: the resolution obtained by the SD only is in agreement with the one obtained from h ... More
Presented by Dr. Simone MALDERA on 4/7/2007 at 15:54
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
We have searched for intermediate-scale anisotropy in the data of the HiRes experiment, in particular the monocular data from the HiRes-II detector. These data were collected between December, 1999, and August, 2005. We see a deficit of events near the direction of the galactic anticenter, very close to the location of the deficit seen by AGASA. Because of low exposure in summer months we ... More
Presented by Prof. Gordon THOMSON on 4/7/2007 at 14:30
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
Several analyses of the data collected by other experiments have found an excess of cosmic rays in correlation with subclasses of BL Lacs. We test these analyses with the data from the Pierre Auger Observatory, and report on the results of our searches.
Presented by Dr. Diego HARARI on 4/7/2007 at 18:05
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
Data taken at the Pierre Auger Observatory are used to search for air showers initiated by ultra-high energy (UHE) photons. The results of searches for UHE photons are reported from hybrid observations (fluorescence and array detectors). Additionally, using the larger data set from the array detectors alone, a more stringent test of predicted large photon fluxes is presented.
Presented by Matthew HEALY on 4/7/2007 at 17:15
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Telescope Array (TA) is a hybrid experiment of an air shower array and fluorescence telescopes installed in Utah, USA. It aims at drawing a conclusion on the (non-)existence of the GZK cutoff reported controversially by the AGASA and HiRes experiments. An anisotropy of the UHECR arrival directions will be studied in the northern hemisphere where the galactic disturbances are small. The u ... More
Presented by Masaki FUKUSHIMA on 7/7/2007 at 17:05
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The clustering properties of the arrival directions of ultra high energy cosmic rays encode important information to determine their origin, composition, and to constrain galactic and extragalactic magnetic fields. We present here the results of a variety of analyses of data from the Pierre Auger Observatory as a function of the angular scale and the energy threshold. We compare our resu ... More
Presented by Dr. Silvia MOLLERACH on 4/7/2007 at 18:15
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Pierre Auger Observatory has been collecting data in a stable manner since January 2004. We present here a study of the cosmic ray composition using events recorded in hybrid mode during the first three years of data taking. These are air showers observed by the fluorescence detector as well as the surface detector, so the depth of shower maximum (Xmax) is measured directly. T ... More
Presented by Dr. Michael UNGER on 4/7/2007 at 17:25
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Pierre Auger Observatory employs a wide range of atmospheric monitoring instruments: two laser facilities; elastic lidar stations; aerosol phase function monitors; a horizontal attenuation monitor; star monitors; weather stations; and balloon soundings. Using all available analyzed atmospheric data we tested the impact on the shower reconstruction, namely on the shower energy and the posi ... More
Presented by Michael PROUZA on 4/7/2007 at 15:42
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
We have developed detector simulators for the TA fluorescence telescopes (FD) and the surface particle detector array. In this paper we describe a new method to evaluate the TA-FD aperture with a Monte-Carlo technique. Since the field of view and the effective area for the FDs are quite large, a considerable CPU cost is required for air shower simulations in the full observable region. In ... More
Presented by Dr. Yoshiki TSUNESADA on 7/7/2007 at 17:41
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Pierre Auger Observatory allows the measurement of both longitudinal profiles and lateral particle distributions of high energy showers. The former trace the overall shower development, mainly of the electromagnetic component close to the core, and the latter reflect the particle densities in the tail of the shower far away from the core, and are sensitive to both the muonic and electrom ... More
Presented by Dr. Ralph ENGEL on 4/7/2007 at 17:35
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The fluorescence measurement is the key in observations of ultra high energy cosmic rays and in determinations of their primary energies in the TA experiment. All the fluorescence detectors of TA will be in operation from June 2007. In this talk, we will present the characteristics of the telescopes and the status of the associated systems including for the atmospheric monitoring and the PMT c ... More
Presented by Dr. Shoichi OGIO on 7/7/2007 at 17:29
Type: Oral Session: HE 1.4.A
Track: HE.1.4.A
The Southern part of the Pierre Auger Observatory, which is nearing completion, has been in stable operation since January 2004 whilst it has grown in size. The large sample of data collected so far has led to a significant improvement to the energy spectrum of UHE cosmic rays over that previously reported by the Pierre Auger Observatory, both in with regard to statistics and systematic uncert ... More
Presented by Dr. Yamamoto TOKANATSU on 4/7/2007 at 16:42
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