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RHESSI Updates�12 July 2022

Brian Dennis

Kim Tolbert

Albert Shih

Andrew Inglis

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RHESSI Mission Archive

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New Flare Catalog

  • Uses new roll database - online.
  • Better flare positions
  • Lower count rate threshold
    • more long-duration flares and small flares
  • Improved detection and location of flares after 2016
  • Quicklook plots in Browser updated.
  • Flare ID numbers consistent with old catalog

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Data-quality Plots

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Flare Image Archive� - Completed first pass� - Waiting for final flare catalog

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Energy Spectra� Waiting for final calibration

  • Standard energy resolution – first version through 2015
  • High energy resolution for >50 keV flares
  • Gamma-ray events (<20)
  • Flare peak spectra for Browser

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Visibility Archive� Completed First Pass� Waiting for final flare catalog

  • All flare times
  • Same Time/energy bins as in image archive
  • Finer resolution time/energy bins

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Solar Aspect System Calibrated Archive� Provided by Martin Fivian� Complete and online

  • SAS limb data orbital FITS files
  • SAS image data daily FITS files
  • Full RHESSI mission

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Roll Angle System Calibrated Database

Complete and online

  • Verified roll angle database
  • Corrected most original roll-angle errors
  • Full RHESSI mission

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Other Databases

  • Gamma-ray Bursts
    • Text file available
  • Terrestrial Gamma-ray Flashes (TGFs)
    • List of published surveys using RHESSI data

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Future of RHESSI Archive

  • You will still use https://hesperia.gsfc.nasa.gov/rhessi
  • All data will be copied to the Solar Data Analysis Center (SDAC)
    • SDAC will be used as a deep archive
  • HESPERIA will still be the primary data server
  • RHESSI web site will still be on HESPERIA
  • RHESSI Browser will be moved from Berkeley to HESPERIA
  • RHESSI Nuggets Wiki will be hosted at another site (TBD)

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Energy Calibration Status

  • Albert Shih & Andrew Inglis

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Recalibration for spectroscopy (“Pass 2”)

  • We are recalibrating RHESSI’s energies (“gain”) and spectral resolution for the entire mission (2002–2018)
  • This work is being done for the following reasons:
    • To ensure a consistent calibration methodology across the entire mission
    • To ensure that the methodology is well-documented and reproducible
    • To make improvements to the gain and resolution where needed
    • To record known and suspected difficulties with the calibration
  • For the most part, the changes to the calibration are minor, and minor changes are negligible for imaging
  • No attempt is made to correct for time-dependent sensitivity

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Calibration methodology

  • Fit three background lines
    • 10.37 keV (front segments)
    • 93.3 keV
    • 511 keV
  • Gain function is linear (two unknowns)
  • Resolution function is quadratic with one fixed coefficient (two unknowns)

Solid lines are line centers

Dashed lines are FWHM

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Recalibration example: relative energy

  • The slope of the linear gain function is the channel width (nominally, ∼⅓ keV)
  • Plot shows from 2006 to the first anneal, in 2007
    • Recalibration in black
    • Existing database in red
  • Most changes are ≲1%

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Recalibration example: absolute energy

  • We want the calibration of the 10.37 keV line to be as accurate as possible
  • Plot shows from launch, in 2002, to the end of 2005
    • Recalibration in black
    • Existing database in red
  • Changes are typically ≲¼ times the width of a channel 🡪 ≲0.1 keV