Documentation scienceplus.abes.fr version Bêta

À propos de : Instrumental oscillations in RHESSI count rates during solar flares        

AttributsValeurs
type
Is Part Of
Subject
Title
  • Instrumental oscillations in RHESSI count rates during solar flares
Date
has manifestation of work
related by
Author
Abstract
  • Aims. We seek to illustrate the analysis problems posed by RHESSI spacecraft motion by studying persistent instrumental oscillations found in the lightcurves measured by RHESSI’s X-ray detectors in the 6-12 keV and 12-25 keV energy range during the decay phase of the flares of 2004 November 4 and 6. Methods. The various motions of the RHESSI spacecraft which may contribute to the manifestation of oscillations are studied. The response of each detector in turn is also investigated. Results. We find that on 2004 November 6 the observed oscillations correspond to the nutation period of the RHESSI instrument. These oscillations are of greatest amplitude for detector 5, while in the lightcurves of many other detectors the oscillations are small or undetectable. We also find that the variation in detector pointing is much larger during this flare than the counterexample of 2004 November 4. Conclusions. Sufficiently large nutation motions of the RHESSI spacecraft lead to clearly observable oscillations in count rates, posing a significant hazard for data analysis. This issue is particularly problematic for detector 5 due to its design characteristics. Dynamic correction of the RHESSI counts, accounting for the livetime, data gaps, and the transmission of the bi-grid collimator of each detector, is required to overcome this issue. These corrections should be applied to all future oscillation studies.
article type
publisher identifier
  • aa16322-10
Date Copyrighted
Rights
  • © ESO, 2011
Rights Holder
  • ESO
is part of this journal
is primary topic of



Alternative Linked Data Documents: ODE     Content Formats:       RDF       ODATA       Microdata