An outburst of SS 433 observed on milliarcsecond scale
Proceedings of Science 125 (2010)
Abstract:
SS 433 is a high-mass X-ray binary system (XRB) and one of the most persistent sources of relativistic jets in the Milky Way. The object has been intensively studied in radio at arcsecond scales, however the high-resolution observations (i.e. VLBI) are relatively scarce. In 2008 November the system was in outburst. Using the e-VLBI capabilities of the European VLBI Network (EVN) we observed SS 433 for three epochs during the active phase. The data offered a detailed view of the system’s behaviour in outburst at milliarcsecond scales. We used the “kinematic model� (which predicts the position along the jet of any knot ejected at some particular time in the past) to investigate the dynamic parameters of SS 433 and we examined the polarization properties of the ejected material. We report here the preliminary results.CMS data processing workflows during an extended cosmic ray run
Journal of Instrumentation 5:3 (2010)
Abstract:
The CMS Collaboration conducted a month-long data taking exercise, the Cosmic Run At Four Tesla, during October-November 2008, with the goal of commissioning the experiment for extended operation. With all installed detector systems participating, CMS recorded 270 million cosmic ray events with the solenoid at a magnetic field strength of 3.8 T. This paper describes the data flow from the detector through the various online and offline computing systems, as well as the workflows used for recording the data, for aligning and calibrating the detector, and for analysis of the data. © 2010 IOP Publishing Ltd and SISSA.Calibration of the CMS drift tube chambers and measurement of the drift velocity with cosmic rays
Journal of Instrumentation 5:3 (2010)
Abstract:
This paper describes the calibration procedure for the drift tubes of the CMS barrel muon system and reports the main results obtained with data collected during a high statistics cosmic ray data-taking period. The main goal of the calibration is to determine, for each drift cell, the minimum time delay for signals relative to the trigger, accounting for the drift velocity within the cell. The accuracy of the calibration procedure is influenced by the random arrival time of the cosmic muons relative to the LHC clock cycle. A more refined analysis of the drift velocity was performed during the offline reconstruction phase, which takes into account this feature of cosmic ray events. © 2010 IOP Publishing Ltd and SISSA.Commissioning and performance of the CMS silicon strip tracker with cosmic ray muons
Journal of Instrumentation 5:3 (2010)
Abstract:
During autumn 2008, the Silicon Strip Tracker was operated with the full CMS experiment in a comprehensive test, in the presence of the 3.8 T magnetic field produced by the CMS superconducting solenoid. Cosmic ray muons were detected in the muon chambers and used to trigger the readout of all CMS sub-detectors. About 15 million events with a muon in the tracker were collected. The efficiency of hit and track reconstruction were measured to be higher than 99% and consistent with expectations from Monte Carlo simulation. This article details the commissioning and performance of the Silicon Strip Tracker with cosmic ray muons. © 2010 IOP Publishing Ltd and SISSA.Commissioning of the CMS experiment and the cosmic run at four tesla
Journal of Instrumentation 5:3 (2010)