Geomagnetic field and altitude effects on the performance of future IACT arrays

The performance of IACT's arrays is sensitive to the altitude and geomagnetic field (GF) of the observatory site. Both effects play important role in the region of the sub-TeV gamma-ray measurements. We investigate the influence of GF on detection rates and the energy thresholds for five possible locations of the future CTA observatory using the Monte Carlo simulations. We conclude that the detection rates of gamma rays and the energy thresholds of the arrays can be fitted with linear functions of the altitude and the component of the GF perpendicular to the shower axis core. These results can be directly extrapolated for any possible localization of the CTA. In this paper we also show the influence of both geophysical effects on the images of shower and gamma/hadron separation.Comment: 4 pages, 6 figures, two-column. Contribution to ICRC 2013 proceeding

Spectral and temporal properties of Compton scattering by mildly relativistic thermal electrons

We have obtained new solutions and methods for the process of thermal. Comptonization, We modify the solution to the kinetic equation of Sunyaev and Titarchuk to allow its application up to mildly relativistic electron temperatures and optical depths = 1, The solution can be used for spectral fitting of X-ray spectra from astrophysical sources, We also have developed an accurate Monte Carlo method for calculating spectra and timing properties of thermal Comptonization sources, The accuracy of our kinetic equation solution is verified by comparison with the Monte Carlo results, We also compare our results with those of other publicly available methods. Furthermore, based on our Monte Carlo code, we present distributions of the photon emission times and the evolution of the average photon energy for both up and down scattering

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA

Performance of the Cherenkov Telescope Array in the presence of clouds

The Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed energies and spectra. This study presents the impact of various atmospheric conditions on CTA performance. The atmospheric transmission in a cloudy atmosphere in the wavelength range from 203 nm to 1000 nm was simulated for different cloud bases and different optical depths using the MODerate resolution atmospheric TRANsmission (MODTRAN) code. MODTRAN output files were used as inputs for generic Monte Carlo simulations. The analysis was performed using the MAGIC Analysis and Reconstruction Software (MARS) adapted for CTA. As expected, the effects of clouds are most evident at low energies, near the energy threshold. Even in the presence of dense clouds, high-energy gamma rays may still trigger the telescopes if the first interaction occurs lower in the atmosphere, below the cloud base. A method to analyze very high-energy data obtained in the presence of clouds is presented. The systematic uncertainties of the method are evaluated. These studies help to gain more precise knowledge about the CTA response to cloudy conditions and give insights on how to proceed with data obtained in such conditions. This may prove crucial for alert-based observations and time-critical studies of transient phenomena

Quantum vacuum and accelerated expansion

A new approach to extraction of quantum vacuum energy, in the context of the accelerated expansion, is proposed, and it is shown that experimentally realistic orders of values can be derived. The idea has been implemented in the framework of the Friedmann–Lemaître–Robertson–Walker geometry in the language of the effective action in the relativistic formalism of Schwinger's proper time and Seeley–DeWitt's heat kernel expansion

Niezwykły objaw raka jasnokomórkowego – opis przypadku

The metabolism of neoplastic cells is perceived as the cause of atherothrombotic incidents in cancers since the 19th century. Those incidents occur in 1–11% cancer cases. In clear cell carcinoma, accounting for 5% of ovarian cancers, atherothrombotic incidents tend to occur 2.5 times more frequently. Clear cell carcinoma is diagnosed earlier and at a younger age compared to other ovarian cancers. The cancer is also characterized by drug resistance to standard treatment. A 47-year-old patient was admitted to the Department of Gynaecology and Obstetrics of School of Medicine in Katowice to treat a tumor of the right ovary. The tumor was detected a month before during the diagnostics of an ischemic stroke which occurred despite no risk factors being present. A laparotomy was performed and the tumor, left adnexa and uterus were removed, according to ovarian cancer protocol. Histopathological examination confirmed the diagnosis of adenocarcinoma clarocellulare (clear cell carcinoma – CCC). The patient was referred for further oncological treatment on 5th day after surgery. Oncological alertness needs to be maintained in cases of unexplained atherothrombotic incidents. An interdisciplinary approach can improve patients’ prognosis by diagnosing the cancer earlier.Choroba nowotworowa już od dawna uznawana jest za przyczynę incydentów zakrzepowo-zatorowych. Incydenty te występują w 1–11% przypadków raków. W raku jasnokomórkowym, który stanowi około 5% nowotworów złośliwych jajnika, incydenty zakrzepowo-zatorowe występują 2,5 razy częściej niż w innych typach histologicznych. Rak jasnokomórkowy jest rozpoznawany u młodszych kobiet i we wcześniejszym stadium. Nowotwór cechuje też chemiooporność na standardowe leczenie. Kobieta 47-letnia została przyjęta do Kliniki Ginekologii i Położnictwa Wydziału Lekarskiego w Katowicach w celu leczenia guza (raka) przydatków prawych, którego wykryto miesiąc wcześniej w trakcie diagnostyki udaru niedokrwiennego. Udar wystąpił mimo braku czynników obciążających. Wykonano laparotomię według protokołu raka jajnika. Badanie histopatologiczne potwierdziło rozpoznanie: rak jasnokomórkowy (clear cell carcinoma – CCC). Pacjentkę w 5 dobie po operacji wypisano ze szpitala i skierowano do dalszego leczenia onkologicznego. Interdyscyplinarne podejście zespołu lekarskiego może poprawić rokowanie pacjentek przez wcześniejsze wykrycie nowotworu. Należy zachować czujność onkologiczną w przypadku niewyjaśnionego incydentu zakrzepowo-zatorowego

Performance of the Cherenkov Telescope Array in the presence of clouds

The Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed energies and spectra. This study presents the impact of various atmospheric conditions on CTA performance. The atmospheric transmission in a cloudy atmosphere in the wavelength range from 203 nm to 1000 nm was simulated for different cloud bases and different optical depths using the MODerate resolution atmospheric TRANsmission (MODTRAN) code. MODTRAN output files were used as inputs for generic Monte Carlo simulations. The analysis was performed using the MAGIC Analysis and Reconstruction Software (MARS) adapted for CTA. As expected, the effects of clouds are most evident at low energies, near the energy threshold. Even in the presence of dense clouds, high-energy gamma rays may still trigger the telescopes if the first interaction occurs lower in the atmosphere, below the cloud base. A method to analyze very high-energy data obtained in the presence of clouds is presented. The systematic uncertainties of the method are evaluated. These studies help to gain more precise knowledge about the CTA response to cloudy conditions and give insights on how to proceed with data obtained in such conditions. This may prove crucial for alert-based observations and time-critical studies of transient phenomena. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0