Global Oscillations at Low Frequencies - Data Analysis Resources

The GOLF team is anxious to encourage any scientists wishing to get involved in the analysis of GOLF data. GOLF data is now in the public domain. As the words imply, GOLF exercises no control on the use of, or publications involving, these data. However, we are always ready, if requested, to give advice on valid ways in which they can be interpreted. Users are requested to include an appropriate acknowledgement in publications involving these data.
Two levels of data are available, either through the SoHO archive or through the following direct links:

Level 1

These are time series of observed intensities in one wing of the sodium lines used by GOLF (see Operation chronology).
In the SOHO archive, they are stored in daily files (FITS format).
These daily FITS files can be read using an IDL routine. These files contains other informations including technical data (temperature of the detectors, etc...) corresponding to different file extension values (see IDL routine and the file headers), not normally required by scientific user.
These intensities can be used instead of velocities in a harmonic analysis. However, since the calibration intensity to velocity varies with time, this will lead to an elevated noise level at low frequencies. Level 1 data can be used for serious research for 5 minute modes.

Level 2

These data are made of calibrated velocities. The calibration technique cannot be perfect and is the result of research efforts by individual GOLF Team scientists. Six sets are available representing 3 different calibration methods and the 2 parallel detectors PM1 and PM2. We have reason to suspect a slightly enhanced noise contribution from PM1. The user can choose to avoid this by using only PM2, or to reduce counting noise by summing the two. The first 4 time series (calibration L2A and L2B) cover 11/4/1996 to 15/9/2004 (with a sampling of 20s). The last 2 series (calibration L2C) cover 11/4/1996 to 8/7/2008. All series can be obtained (in FITS format) by clicks on the following links:

• Calibration L2A by Luca Bertello, described in Ulrich et al.: data from PM1 and PM2
• Calibration L2B by Gerard Grec, described in Gelly et al.: data from PM1 and PM2
• Calibration L2C by Rafael Garcia, described in Garcia et al.: data from PM1 and PM2

Below, links to online information resources relevant to the analysis of the data are provided.

• Instrument/hardware description

  • Solar Physics paper describing the instrument (PS format)
  • First results: Gabriel et al. 1997
  • Operations since the launch
  
  

• Reference library

  • GOLF related publications

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