M. Dyrda

Novel analysis of a sudden ionospheric disturbance using Schumann resonance measurements

A spherical cavity between Earth and the lower ionosphere forms a global resonator for Extremely Low Frequency electromagnetic waves. Constant thunderstorm activity leads to the formation of a resonance field in the cavity, known as the Schumann resonance. Solar flare generated Sudden Ionospheric Disturbances (SID) modify the ionosphere affecting the ground-based radio communication systems. They are also expected to modify radiowave propagation in the cavity. In this paper, the Schumann Resonance spectral decomposition method is used for the first time to study the cavity resonance frequencies during the SID accompanying a strong X2.1 solar flare. We analyzed rapid changes in the frequencies and Q factors of the first five resonance modes using a 5 min timescale. The observed frequency shifts were compared to the ionizing solar flare fluxes in the UV, X-ray, and high-energy γ rays.

Status of the technologies for the production of the Cherenkov telescope array (CTA) mirrors

The Cherenkov Telescope Array (CTA) is the next generation very high-energy gamma-ray observatory, with at least 10 times higher sensitivity than current instruments. CTA will comprise several tens of Imaging Atmospheric Cherenkov Telescopes (IACTs) operated in array-mode and divided into three size classes: large, medium and small telescopes. The total reflective surface could be up to 10,000 m2 requiring unprecedented technological efforts. The properties of the reflector directly influence the telescope performance and thus constitute a fundamental ingredient to improve and maintain the sensitivity. The R&D status of lightweight, reliable and cost-effective mirror facets for the CTA telescope reflectors for the different classes of telescopes is reviewed in this paper.

Prototype of the SST-1M Telescope Structure for the Cherenkov Telescope Array

A single-mirror small-size (SST-1M) Davies-Cotton telescope with a dish diameter of 4 m has been built by a consortium of Polish and Swiss institutions as a prototype for one of the proposed small-size telescopes for the southern observatory of the Cherenkov Telescope Array (CTA). The design represents a very simple, reliable, and cheap solution. The mechanical structure prototype with its drive system is now being tested at the Institute of Nuclear Physics PAS in Krakow. Here we present the design of the prototype and results of the performance tests of the structure and the drive and control system.

Discovery of VHE gamma-rays from the radio galaxy PKS 0625-354 with H.E.S.S

Michal Dyrda∗a, Alicja Wierzcholskab,a†, Olivier Hervetc, Rafal Moderskid, Mateusz Janiakd, Michal Ostrowskie and Łukasz Stawarze for the H.E.S.S. Collaboration a Institute of Nuclear Physics, PAS, ul. Radzikowskiego 152, 31-342 Krakow, Poland b Landessternwarte, Universitat Heidelberg, Konigstuhl 12, D 69117 Heidelberg, Germany c LUTH, Observatoire de Paris, CNRS, Universit Paris Diderot, 5 Place Jules Janssen, 92190

Application of the Schumann resonance spectral decomposition in characterizing the main African thunderstorm center

In this paper we present a new method for quantifying the main tropical thunderstorm regions based on extremely low frequency (ELF) electromagnetic wave measurements from a single station—the Hylaty ELF station in Central Europe. Our approach is based on Schumann resonance (SR) measurements, which we apply as an example to thunderstorms in Africa. By solving the inverse problem, using the SR power spectrum templates derived analytically, we calculate distances to the most powerful thunderstorm centers and present simplified 1-D thunderstorm lightning activity “maps” in absolute units C2m2/s. We briefly describe our method of SR power spectrum analysis and present how this method is used with real observational data. We obtained the monthly lightning activity maps of the African storm centers with a spatial resolution of 1° and temporal resolution of 10 min for January and August 2011. This allowed us to study the varying location and intensities of the African storm centers in different seasons of the year. A cross check of the obtained lightning activity maps with Tropical Rainfall Measuring Mission satellite data recorded by the Lightning Imaging Sensor and the derived correlation coefficients between SR and optical data were used to validate the proposed method. We note that modeling a maximum possible number of resonance modes in the SR power spectra (in our case, seven resonances) is essential in application of the proposed approach.

Using muon rings for the optical throughput calibration of the SST-1M prototype for the Cherenkov Telescope Array

S. Toscano∗ a,n, E. Prandinia E-mail: simona.toscano@vub.ac.be W. Bilnikk, J. Blockic, L. .Bogaczm, T .Bulikd , F. Cadouxb, A. Christovb, M. Curyloc, D. della Volpeb, M. Dyrdac, Y. Favreb, A. Frankowskig, Ł. Grudnikic, M. Grudzinskad , M. Hellerb, B. Idźkowskie, M. Jamrozye, M. Janiakg, J. Kasperekk, K. Lalikk, E. Lyarda, E. Machc, D. Mandatl , A. Marszalekc,e, J. Michalowskic, R. Moderskig, T. Montarulib, A. Neronova, J. Niemiecc, M. Ostrowskie, P. Paśko f , M. Pechl , A. Porcellib, P. Rajdak, M. Rameezb, E. Jr. Schioppab, P. Schovanekl , K. Seweryn f , K. Skowronc, V. Sliusar j, M. Sowinskic, Ł. Stawarze, M. Stodulskae, M. Stodulskic, I. Troyano Pujadasb, R. Waltera, M. Wiȩcekk, A. Zagdanskie, K. Ziȩtarae, P. Żychowskic for the CTA Consortium† a. ISDC, Observatoire de Geneve, Universite de Geneve, 1290 Versoix, Switzerland. b. Department de physique nucleaire et corpusculaire, Universite de Geneve, CH-1205 Switzerland. c. Instytut Fizyki Jadrowej im. H. Niewodniczanskiego Polskiej Akademii Nauk, 31-342 Krakow, Poland. d. Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw, Poland e. Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244, Krakow, Poland. f. Centrum Badan Kosmicznych Polskiej Akademii Nauk, 18a Bartycka str., 00-716 Warsaw, Poland. g. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw, Poland. j. Astronomical Observatory, Taras Shevchenko Nat. University of Kyiv, Observatorna str., 3, Kyiv, Ukraine. k. AGH University of Science and Technology, al.Mickiewicza 30, Krakow, Poland, l. Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic. m. Department of Information Technologies, Jagiellonian University, 30-348 Krakow, Poland. n. Vrije Universiteit Brussels, Pleinlaan 2 1050 Brussels, Belgium.

Development of an optical system for the SST-1M telescope of the Cherenkov Telescope Array observatory

The prototype of a Davies-Cotton small size telescope (SST-1M) has been designed and developed by a consortium of Polish and Swiss institutions and proposed for the Cherenkov Telescope Array (CTA) observatory. The main purpose of the optical system is to focus the Cherenkov light emitted by extensive air showers in the atmosphere onto the focal plane detectors. The main component of the system is a dish consisting of 18 hexagonal mirrors with a total effective collection area of 6.47 m 2 (including the shadowing and estimated mirror reflectivity). Such a solution was chosen taking into account the analysis of the Cherenkov light propagation and based on optical simulations. The proper curvature and stability of the dish is ensured by the mirror alignment system and the isostatic interface to the telescope structure. Here we present the design of the optical subsystem together with the performance measurements of its components.

Performance of the small size telescope sub-array of the Cherenkov Telescope Array observatory

The southern part of the Cherenkov Telescope Array (CTA) observatory will consist of at least three types of telescopes: large size, medium size and small size telescopes. Massive Monte Carlo simulations have been performed using the European Grid Infrastructure to analyze the performance of this array. We present the results of these simulations for a sub-array of small size telescopes of the Davies-Cotton type. Such a telescope, called SST-1M, is currently being proposed for the CTA observatory by a group of Polish and Swiss institutions. SST-1M will have a mirror of 4m diameter and it will be equipped with a fully digital camera based on silicon photodetectors. We present the analysis of the sub-array sensitivity, angular resolution, and energy resolution to demonstrate the fulfillment of the requirements of the CTA Consortium. To verify the results obtained in numerical simulations a construction of a mini array of five SST-1M telescopes is planned. We also present the performance of such a mini array and discuss the prospects of its scientific program.

DigiCam: fully digital compact camera for SST-1M telescope

The single mirror Small Size Telescopes (SST-1M), being built by a sub-consortium of Polish and Swiss Institutions of the CTA Consortium, will be equipped with a fully digital camera with a compact photodetector plane based on silicon photomultipliers. The internal trigger signal transmission overhead will be kept at low level by introducing a high level of integration. It will be achieved by massively deploying state-of-the-art multi-gigabit transceivers, beginning from the ADC flash converters, through the internal data and trigger signals transmission over backplanes and cables, to the camera’s server 10Gb/s Ethernet links. Such approach will allow fitting the size and weight of the camera exactly to the SST-1M needs, still retaining the flexibility of a fully digital design. Such solution has low power consumption, high reliability and long lifetime. The concept of the camera will be described, along with some construction details and performance results.

Performance of the SST-1M telescope of the Cherenkov Telescope Array observatory

R. Moderskic,W. Bilnikk, J. Blockig, L. Bogacze, T. Bulikd , F. Cadouxa, A. Christova, M. Chruślinskad , M. Curylog, D. della Volpea, M. Dyrdag, Y. Favrea, A. Frankowskic, Ł. Grudnikg, M. Grudzinskad , M. Hellera, B. Idźkowskib, M. Jamrozyb, M. Janiakc, J. Kasperekk, K. Lalikk, E. Lyard f , E. Machg, D. Mandatm, A. Marszalekh,b, J. Michalowskig, T. Montarulia, A. Neronov f , J. Niemiecg, M. Ostrowskib, P. Paśkoh, M. Pechm, A. Porcelli∗a, E. Prandini f , E. Puescheln, P. Rajdak, M. Rameeza, P. Rozwadowskid , E. jr Schioppaa, P. Schovanekm, K. Sewerynh, K. Skowrong, V. Sliusari, M. Sowinskig, Ł. Stawarzb, M. Stodulskab, M. Stodulskig, S. Toscano f ,l, I. Troyano Pujadasa, R. Walter f , M. Wiȩcekk, A. Zagdanskib, K. Ziȩtarab, P. Żychowskig for the CTA Consortium† aDPNC – Universite de Geneve, Geneve, Switzerland bAstronomical Observatory, Jagiellonian University, Krakow, Poland cNicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Warsaw, Poland dAstronomical Observatory, University of Warsaw, Warsaw,Poland eDepartment of Information Technologies, Jagiellonian University, Krakow, Poland f ISDC, Observatoire de Geneve, Universite de Geneve, Versoix, Switzerland gInstytut Fizyki Jadrowej im. H. Niewodniczanskiego Polskiej Akademii Nauk, Krakow, Poland hCentrum Badan Kosmicznych Polskiej Akademii Nauk, Warsaw, Poland iAstronomical Observatory, Taras Shevchenko National University of Kyiv, Kyiv, Ukraine kAGH University of Science and Technology, Krakow, Poland lVrije Universiteit Brussels, Brussels, Belgium mInstitute of Physics of the Czech Academy of Sciences, Prague, Czech Republic nUniversity College Dublin, Ireland