Anisotropy of the space orientation of radio sources. I: The catalog

A catalog of the extended extragalactic radio sources consisting of 10461 objects is compiled based on the list of radio sources of the FIRST survey. A total of 1801 objects are identified with galaxies and quasars of the SDSS survey and the Veron-Veron catalog. The distribution of the position angles of the axes of radio sources from the catalog is determined, and the probability that this distribution is equiprobable is shown to be less then 10^(-7). This result implies that at Z equal to or smaller then 0.5, spatial orientation of the axes of radio sources is anisotropic at a statistically significant level.Comment: 8 pages, 7 figure

First Measurements with the ATLAS Level-1 Calorimeter Trigger PreProcessor System

The ATLAS level-1 calorimeter trigger is a hardware-based system with the goal of identifying high-pT objects within an overall latency of 2.5 μs. It is composed of a PreProcessor system which digitises 7200 analogue channels, determines the bunchcrossing of the interaction and provides a fine timing and energy calibration; and two subsequent digital processors. The PreProcessor plays a central role during integration of the system as it provides digitisation and readout of calorimeter signals and serves as a digital signal source for the subsequent processors. In this presentation the system architecture, the board production testing, and cable installation are described. Results on commissioning efforts and signal integrity tests are presented

Production Test Rig for the ATLAS Level-1 Calorimeter Trigger Digital Processors

The Level-1 Calorimeter Trigger is a digital pipelined system, reducing the 40 MHz bunch-crossing rate down to 75 kHz. It consists of a Preprocessor, a Cluster Processor (CP), and a Jet/Energy-sum Processor (JEP). The CP and JEP receive digitised trigger-tower data from the Preprocessor and produce electron/photon, tau, and jet trigger multiplicities, total and missing transverse energies, and Region-of-Interest (RoI) information. Data are read out to the data acquisition (DAQ) system to monitor the trigger by using readout driver modules (ROD). A dedicated backplane has been designed to cope with the demanding requirements of the CP and JEP sub-systems. A number of pre-production boards were manufactured in order to fully populate a crate and test the robustness of the design on a large scale. Dedicated test modules to emulate digitised calorimeter signals have been used. All modules, cables and backplanes on test are final versions for use at the LHC. This test rig represents up to one third of the Level-1 digital processor system. Real-time data between modules were processed and time-slice readout data was transferred to the ROD at a trigger rate up to 100 kHz. Intensive testing consisted of checking the readout data by comparing to hardware simulations of the trigger. Domains of validity of the boards were also measured and dedicated stressful data patterns were used to check the reliability of the system. Tests results have been successful and the Level-1 calorimeter trigger system is proceeding to full production

Commissioning of the Jet/Energy-sum and Cluster Processors for the ATLAS Level-1 Calorimeter Trigger System

The ATLAS first-level calorimeter trigger is a hardwarebased system designed to identify high-pT jets, electron/photon and tau candidates, and to measure total and missing ET. The trigger consists of a Preprocessor system which digitises 7200 analogue inputs, and two digital multicrate processor systems which find jets, measure energy sums, and identify localised energy deposits (electron/photon and tau candidates). In order to provide a trigger quickly enough, the hardware is parallel and pipelined. Experience so far of the Jet/Energy-sum and Cluster Processor system production, commissioning, and integration into ATLAS will be described

On the Hadronic Beam Model for Gamma-ray Production in Blazars

We consider, herein, a model for gamma-ray production in blazars in which a relativistic, highly-collimated electron-proton beam interacts with a dense, compact cloud as the jet propagates through the broad and perhaps narrow line regions (BLR and NLR) of active galactic nuclei (AGN). During the propagation of the beam through the cloud, the process of excitation of plasma waves becomes an important energy loss mechanism, especially for mildly relativistic proton beams. We compute the expected spectra of gamma-rays from the decay of neutral pions produced in hadronic collisions of the beam with the cloud, taking into account collisionless losses of the electron-proton beam. This model may explain the X-ray and TeV gamma-ray (both low and high emission states) of Mrk 421 as a result of synchrotron emission of secondary pairs from the decay of charged pions and gamma-ray emission from the decay of neutral pions for the plausible cloud parameters. However clouds can not be too hot and too dense. Otherwise the TeV gamma-rays can be attenuated by the bremsstrahlung radiation in the cloud and the secondary pairs are not able to efficiently produce synchrotron flares because of the dominant role of inverse Compton scattering. The non-variable $\gamma$-ray emission observed from Mrk 421 in the EGRET energy range cannot be described by the $\gamma$-rays from decay of neutral pions provided that the spectrum of protons in the beam is well described by a simple power law. These $\gamma$-rays might only be produced by secondary pairs scattering the soft non-variable X-rays which might originate in the inner part of the accretion disk.Comment: 14 pages,3 figures, latex, submitted to Ap