1,721,005 research outputs found
Searching for PeVatrons in the CTA Galactic Plane Survey
No full textThe Cherenkov Telescope Array (CTA) will perform a survey of the whole Galactic disk with unprecedented sensitivity at energies up to 300 TeV. One of the key science projects of the CTA consortium is the discovery of Galactic PeVatrons (cosmic ray accelerators to PeV energies). The determination of efficient criteria to identify PeVatron candidates during the Galactic plane survey observations is essential in order to trigger deeper observations. This contribution presents a method which relies on the broadband spectrum of the source to investigate high energy spectral features. The application of this method to specific sources will also be presented
Eine Studie zur Untergrundunterdr\"{u}ckung bei stereoskopischen Cherenkov-Systemen durch Ausnutzung von Pixel-Timing-Information.
No full textA Compact High Energy Camera (CHEC) for the Gamma-ray Cherenkov Telescope of the Cherenkov Telescope Array
No full textThe Gamma-ray Cherenkov Telescope (GCT) is one of the Small Size Telescopes (SSTs) proposed for the Cherenkov Telescope Array (CTA) aimed at the 1 TeV to 300 TeV energy range. GCT will be equipped with a Compact High-Energy Camera (CHEC) containing 2048 pixels of physical size about 66~mm, leading to a field of view of over 8 degrees. Electronics based on custom TARGET ASICs and FPGAs sample incoming signals at a gigasample per second and provide a flexible triggering scheme. Waveforms for every pixel in every event are read out are on demand without loss at over 600 events per second. A GCT prototype in Meudon, Paris saw first Cherenkov light from air showers in late 2015, using the first CHEC prototype, CHEC-M. This contribution presents results from lab and field tests with CHEC-M and the progress made to a robust camera design for deployment within CTA
Contributions from the Cherenkov Telescope Array (CTA) Consortium to the ICRC 2011
Get PDFThe Cherenkov Telescope Array (CTA) is a project for the construction of a next generation VHE gamma ray observatory with full sky coverage. Its aim is improving by about one order of magnitude the sensitivity of the existing installations, covering about 5 decades in energy (from few tens of GeV to above a hundred TeV) and having enhanced angular and energy resolutions. During 2010 the project became a truly global endeavour carried out by a consortium of about 750 collaborators from Europe, Asia, Africa and the North and South Americas. Also during 2010 the CTA project completed its Design Study phase and started a Preparatory Phase that is expected to extend for three years and should lead to the starting of the construction of CTA. An overview of the CTA Consortium activities project will be given
Stellar Intensity Interferometric Capabilities of IACT Arrays
No full textSub-milliarcsecond imaging of nearby main sequence stars and binary systems can provide critical information on stellar phenomena such as rotational deformation, accretion effects, and the universality of starspot (sunspot) cycles. Achieving this level of resolution in optical wavelength bands (U/V) requires use of a sparse array of interferometric telescopes with kilometer scale baseline separations. Current ground based VHE gamma-ray observatories, such as VERITAS, HESS, and MAGIC, employ arrays of > 10 m diameter optical Imaging Atmospheric Cherenkov Telescopes (IACTs) with >80 m telescope separations, and are therefore well suited for sub-milliarcsecond astronomical imaging in the U/V bands using Hanbury Brown and Twiss (HBT) interferometry [1,2]. We describe the development of instrumentation for the augmentation of IACT arrays to perform Stellar Intensity Interferometric (SII) imaging. Laboratory tests are performed using pseudo-random and thermal (blackbody) light to demonstrate the ability of high speed (250 MHz) digitizing electronics to continuously record photon intensity over long periods (minutes to hours) and validate the use of offline software correlation to calculate the squared degree of coherence . We then use as the interferometric observable to populate the Fourier reciporical image plane, and apply standard inversion techniques to recover the original 2-D source image. The commercial availability of inexpensive fiber-optic based sub-nanosecond multi-crate (White Rabbit[3]) synchronization timing enables the extension of SII to baselines greater than 10 km, theoretically allowing U/V band imaging with resolution <100 arc-seconds. This article provides a description of typical designs of practical SII instrumentation for the VERITAS IACT observatory array (Amado, Arizona) and the future CTA IACT Observatory (Canary Islands, Spain and Paranal, Chile)
A Monte Carlo simulation study for cosmic-ray chemical composition measurement with Cherenkov Telescope Array
No full textOur Galaxy is filled with cosmic-ray particles and more than 98% of them are atomic nuclei. In order to clarify their origin and acceleration mechanism, chemical composition measurements of these cosmic rays with wide energy coverage play an important role. Imaging Atmospheric Cherenkov Telescope (IACT) arrays are designed to detect cosmic gamma-rays in the very-high-energy regime (TeV). Recently these systems proved to be capable of measuring cosmic-ray chemical composition in the sub-PeV region by capturing direct Cherenkov photons emitted by charged primary particles. Extensive air shower profiles measured by IACTs also contain information about the primary particle type since the cross section of inelastic scattering in the air depends on the primary mass number. The Cherenkov Telescope Array (CTA) is the next generation IACT system, which will consist of multiple types of telescopes and have a km-scale footprint and extended energy coverage (20 GeV to 300 TeV). In order to estimate CTA potential for cosmic ray composition measurement, a full Monte Carlo simulation including a description of extensive air shower and detector response is needed. We generated a number of cosmic-ray nuclei events (8 types selected from H to Fe) for a specific CTA layout candidate in the southern-hemisphere site. We applied Direct Cherenkov event selection and shower profile analysis to these data and preliminary results on charge number resolution and expected event count rate for these cosmic-ray nuclei are presented
End-to-end data acquisition pipeline for the Cherenkov Telescope Array
No full textThe Cherenkov Telescope Array (CTA) will operate several types of telescopes and cameras. The individual camera trigger rates will vary much - from 0.6 to 15 kHz - while the content of the raw data will be heterogeneous. Raw data streams of up to 43 Gbps per telescope must be handled efficiently, from the camera front-ends down to the on-site repository and real-time analysis. In addition, the system must transcode all raw data to a common, pre-calibrated format. We will present the pipeline that we propose to implement this data acquisition pipeline. It will format the raw data to a common structure, provide facilities to run camera-specific algorithms and compress and write data to the on-site repository. We will also present the Python interface that allows the analysis pipeline to access the data. Eventually, the two strategies foreseen to interface the camera servers will be detailed and the current status of the developments for CTA will be given, with the last performance figures measured
Sun/Moon photometer for the Cherenkov Telescope Array - first results
No full textDetermination of the energy and flux of the gamma photons by Imaging Atmospheric Cherenkov Technique is strongly dependent on optical properties of the atmosphere. Therefore, atmospheric monitoring during the future observations of the Cherenkov Telescope Array (CTA) as well as anticipated long-term monitoring in order to characterize overal properties and annual variation of atmospheric conditions are very important. Several instruments are already installed at the CTA sites in order to monitor atmospheric conditions on long-term. One of them is a Sun/Moon photometer CE318-T, installed at the Southern CTA site. Since the photometer is installed at a place with very stable atmospheric conditions, it can be also used for characterization of its performance and testing of new methods of aerosol optical depth (AOD) retrieval, cloud-screening and calibration. In this work, we describe our calibration method for nocturnal measurements and the modification of cloud-screening for purposes of nocturnal AOD retrieval. We applied these methods on two months of observations and present the distribution of AODs in four photometric passbands together with their uncertainties
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