M. Prouza

The Galactic magnetic field and propagation of ultra-high energy cosmic rays

The puzzle of ultra-high energy cosmic rays (UHECRs) still remains unresolved. With the progress in preparation of next generation experiments (AUGER, EUSO, OWL) grows also the importance of directional analysis of existing and fut ure events. The Galactic magnetic field (GMF) plays the key role i n source identification even in this energy range. We first ana lyze current status of our experimental and theoretical knowledge about GMF and introduce complex up-to-date model of GMF. Then we present two examples of simple applications of influe nce of GMF on UHECR propagation. Both examples are based on Lorentz equation solution. The first one is basic directio nal analysis of the incident directions of UHECRs and the second one is a simulation of a change of chemical composition of CRs in the energy range 10 13 ÷10 19 eV. The results of these simple analyses are surprisingly rich — e.g. the rates of particle e scape from the Galaxy or the amplifications of particle flux in specific directions.

Study of pixel area variations in fully depleted thick CCD

Future wide field astronomical surveys, like Large Synoptic Survey Telescope (LSST), require photometric precision on the percent level. The accuracy of sensor calibration procedures should match these requirements. Pixel size variations found in CCDs from different manufacturers are the source of systematic errors in the flat field calibration procedure. To achieve the calibration accuracy required to meet the most demanding science goals this effect should be taken into account. The study of pixel area variations was performed for fully depleted, thick CCDs produced in a technology study for LSST. These are n-channel, 100μm thick devices. We find pixel size variations in both row and column directions. The size variation magnitude is smaller in the row direction. In addition, diffusion is found to smooth out electron density variations. It is shown that the characteristic diffusion width can be extracted from the flat field data. Results on pixel area variations and diffusion, data features, analysis technique and modeling technique are presented and discussed.

FRAM—The Robotic Telescope for the Monitoring of the Wavelength Dependence of the Extinction: Description of Hardware, Data Analysis, and Results

FRAM—F/(Ph)otometric Robotic Atmospheric Monitor is one of the atmospheric monitoring instruments at the Pierre Auger Observatory in Argentina. FRAM is an optical telescope equipped with CCD cameras and photometer, and it automatically observes a set of selected standard stars. Primarily, FRAM observations are used to obtain the wavelength dependence of the light extinction. FRAM telescope is also able to observe secondary astronomical targets, and namely the detection of optical counterparts of gamma-ray bursts has already proven to be successful. Finally, a wide-field CCD camera of FRAM can be used for rapid monitoring of atmospheric conditions along the track of particularly interesting cosmic ray showers. The hardware setup of the telescope, its software system, data taking procedures, and results of analysis are described in this paper.

Turning a remotely controllable observatory into a fully autonomous system

We describe a complex process needed to turn an existing, old, operational observatory - The Steward Observatory’s 61” Kuiper Telescope - into a fully autonomous system, which observers without an observer. For this purpose, we employed RTS2,1 an open sourced, Linux based observatory control system, together with other open sourced programs and tools (GNU compilers, Python language for scripting, JQuery UI for Web user interface). This presentation provides a guide with time estimates needed for a newcomers to the field to handle such challenging tasks, as fully autonomous observatory operations.

Use of RTS2 for LSST multiple channel CCD characterisation

RTS2, or Remote Telescope System 2nd Version, is a modular observatory control system. Development of RTS2 began in 2003 and since then it has been used at more than 20 observatories world-wide. Its main users are small, fully autonomous observatories, performing target of opportunity observations. Since June 2007 RTS2 has been used at Brookhaven National Laboratory (BNL) to control the acquisition of images for the Large Synoptic Survey Telescope (LSST) CCD characterisation. The CCD test laboratory includes multiple devices which need to be controlled in order to perform the electro-optical testing of the CCD. The configuration of the devices must be recorded in order for that information to be used later during data analysis. The main factors leading to use of RTS2 were its availability, open - source code, and modular design which allows its fast customisation to fit changing needs of a R&D project. This article focuses on the description of changes to the system which allow for the integration of LSSTs multiple output CCD imagers. The text provides details of the multiple channel implementation, which parts of the system were affected, and how these changes influenced overall system design. It also describes how easy and fast it was to run the multiple channel instrument on night and twilight sky during prototype CCD testing, and demonstrates how the complex routines, such as twilight skyflats acquisitions, worked out of the box.

Sun/Moon photometer for Cherenkov Telescope Array – first results

Determination 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.

Software for automated testing and characterization of CCDs for Large Synoptic Survey Telescope (LSST)

We present the latest modifications of the open source observatory control software package RTS2. New features were developed specifically for the automated testing of CCD chips for the mosaic camera of the Large Synoptic Survey Telescope. Currently, the system is in operation at Brookhaven National Laboratory in Upton, USA and at Laboratoire de Physique Nucl´eaire et des Hautes ´Energies in Paris, France. RTS2 software is currently used to characterize the sensors from various vendors and will be used first for selection and then for testing of production CCD sensors. With our system we are able to automatically obtain a series of images for analysis. Data is used to study many aspects of sensor characteristics, including wavelength dependence of quantum efficiency, the dark current, and the linearity of the CCD response as a function of back-bias voltage and temperature. We also can measure a point spread function over the whole surface of the CCD sensors.

Design of modular C++ observatory control system: from observatories to laboratories and back

For almost a decade we have been developing an open source control system for autonomous observatories called Remote Telescope System, 2nd version - RTS2. The system is currently used to operate about dozen observatories. It was designed from the beginning as the ultimate tool for autonomously performing any possible observing plan on any hardware. Its modular design allows exactly this and enables even more. Currently it is used to control not only observatories but also CCD testing laboratories. We present the internal design of this open source observatory and laboratory control package, and discuss its overall structure. We emphasise new developments and our experiences building a community of users and developers of the package. Design of the system modularity is explained in detail, and various approaches to software reuse are discussed, with a demonstration of how the best solution emerged. We describe problems that were encountered as mirror sizes and associated operational complexity grew. We also describe how the system is being used at a CCD testing laboratory, and detail the quick transition from previously unsupported hardware to fully automated operation. We discuss how the systems evolution has affected code design, and present unexpected benefits it is brought. Our experience with use of open source code and libraries are discussed.

GRB 060117 : Reverse + forward shock solution

We present a discovery and observation of an extraordinarily bright prompt optical emission of the GRB 060117 obtained by a wide-field camera atop the robotic telescope FRAM of the Pierre Auger Observatory from 2 to 10 minutes after the GRB. We found rapid average temporal flux decay of alpha = -1.7 +/- 0.1 and a peak brightness R = 10.1 mag. We interpret the shape of the lightcurve as a transition between reverse and forward shock emission.