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VIMOS Quality Control:
IFU calibration

CAL | HC | refs | QC
Trending & QC1
   IFU calib
Data Package
Data Management
QC links:
wavelength calibration | stability
dispersion rms
QC1 database (advanced users): browse | plot
central fibre
lost fibres
fibre trace slope
QC1 database (advanced users): browse | plot
   Click on CURRENT to see the current trending (Health Check).
   Click on HISTORY to see the historical evolution of the trending.

IFU calibrations come, for each quadrant, as a series of flat-field exposures (through the fibre system) plus one arc lamp exposure.

top Wavelength calibration

QC1 parameters

parameter QC1 database: table, name procedure
resolution vimos_ifu_wave, resol1
vimos_ifu_wave, resol2
vimos_ifu_wave, resol3
R = lambda/delta lambda. The spectral resolution is computed for each grism using three selected arc lamp lines with wavelengths close to the center, close to the red, and close to the blue end of the spectrum. The resolution is given by the average on all slits of the ratio between the selected arc lamp line wavelength and its FWHM (Gauss fit)
dispersion rms vimos_ifu_wave, ids_rms rms of the inverse dispersion solution residuals in pixels. The residuals are the differences between the expected line positions and the actual line positions after applying the dispersion solution


date event
2010-07 tilt of focal plane vs. detector plane, upper part of quadrant 4 is out of focus
2011-05 tilt of focal plane is fixed


top IFU stability

All IFU stability parameters are measured for each quadrant and for each pseudo slit separately. For LR grisms, all four pseudo slits are used. For MR and HR grisms, only the central pseudo slit (number 2) is used.

QC1 parameters

parameter QC1 database: table, name procedure
central fibre vimos_ifu_trace, trace1_central
vimos_ifu_trace, trace2_central
vimos_ifu_trace, trace3_central
vimos_ifu_trace, trace4_central
This is the sequence number of the active fibre closest to the central CCD X pixel (1024) at the reference CCD Y pixel. The reference Y pixels are selected depending on grism and quadrant.
number of lost fibres vimos_ifu_trace, num_lost1
vimos_ifu_trace, num_lost2
vimos_ifu_trace, num_lost3
vimos_ifu_trace, num_lost4
The number of fibres that could not be successfully traced on the IFU flats.
fibre slope vimos_ifu_trace, trace1_slope
This is the slope of a reference fibre trace on the detector along a 400 pixel long Y interval. The original pipeline parameter has been multiplied with 4096. This gives the difference between the X positions of the fibre trace at the bottom and the top of the detector.