Knowledgebase: Spitzer: IRS

Spitzer Documentation

All the Spitzer documentation can be found linked from here.

IRS Short-Low (Both) Mapping has non-0 bit-flags in PBCD tune.tbl

This is a note about "tune.tbl" files for Spitzer IRS SL1+SL2 (Both) 5.2-14.5 micron spectral mapping, i.e. when the centering was between the SL1 and SL2 active areas to record the spectra of both ranges simultaneosly (rather than centering SL1 on a source, then SL2). The keyword for this mode is FOVNAME = 'IRS_Short-Lo_Module_Center'. In the Spitzer Heritage Archive Post-BCD tune.tbl files, points can be "overmasked" in the bit-flags for this mode. For example, many points in SPITZER_S0_14587392_0346_8_E7446070_tune.tbl have bit-flag = 12416 = bits 7,12,13, which would normally be fatal. If the data points look otherwise normal, they are usually okay, except for bad end wavelengths and any points with NaNs in flux or error. The safe wavelength ranges are 5.21-7.56 (SL2) and 7.57-14.28 (SL1).

For full confidence, it would be best to run the images through SPICE to make your own final spectrum (bad pixels may be visible on the images).