QC PLOTS
WAVELENGTH:	CURRENT	HISTORY
wavelength
resolving power
X-position of slitlet #17
FWHM of arc lines
number of detected arc lines
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.

Arc lamp frames are used to create and monitor the SINFONI wavelength solutions and are routinely obtained on a daily basis. Each arc lamp is exposed in pairs made up of lamp-on and lamp-off frames and are made for each of the available gratings (J, H, K, and H+K) and pixel scales (25, 100, and 250 mas). They are processed into a number of product frames

A stacked SINFONI wavelength calibration arc lamp. The 32 slitlets are evident in this image.

The pipeline-derived wavelength solution applied to the above arc lamp frame results in this resampled WAVE image. This product is solely created for quality control and is used to check the quality of the global dispersion solution.

QC1 plots

The QC1 plots for the SINFONI WAVE show the:

• wavelength for the J, H, K, and H+K gratings and the 25, 100, and 250 mas pixel scales (in microns)
• spectral resolution for the J, H, K, and H+K gratings (250 mas pixel scale only)
• X-axis position of the center of the 17th slitlet (in pixels)
• full width half-maximum of the identified arc lines (in pixels)
• number of identified arc lines

QC1 parameters trended

QC Reports for Wavelength Calibration

QC Report 1 (images):
UL: an image of the current resampled arc line frame (RESAMPLED_WAVE).
UC: an image of the reference resampled arc line frame (RESAMPLED_WAVE).
UR: the difference between the reference and the current resampled arc line frames.
LL: an image of the current pipeline-computed wavelength solution (WAVE_MAP).
LC: an image of the reference pipeline-computed wavelength solution (WAVE_MAP).
LR: the difference between the reference and the current pipeline-computed wavelength solution.

QC Report 2 (coefficients):
This report comprises a four panel plot of the coefficients computed for the wavelength solution. The coefficients are defined for each row (y-axis) such that:
lambda = C0 + C1*x + C2*x² + C3*x³ [where: x = y - (Ny-1)/2, and Ny is the number of y-axis pixels (2048)].
The current (shown in blue) and the reference (shown in red) coefficient values are plotted for each of the 32 slitlets.
top: O^th order coefficient C0.
top center: 1^st order coefficient C1.
lower center: 2^nd order coefficient C2.
bottom: 3^rd order coefficient C3.

QC Report 3                                                                                                                                     QC Report 4

QC Report 3 (arc lines):
This report shows plots of the extracted, calibrated, arc line spectra. The current arc spectra are shown in blue and the reference spectra is plotted in red.
top: the full range arc line spectrum extracted along column pixel 1000. Green dots show which arc lines have been detected by the SINFONI pipeline. All emission lines contained in the arc line reference table are marked with a thin black line and have their wavelengths labelled.
LL: zoomed region 1 of the arc line spectrum. The pixel values of the zoom are given in the top left corner of the frame and the zoom region is shown as a horizontal line in the upper full-scale plot.
LC: zoomed region 2 of the arc line spectrum. As above.
LR: zoomed region 3 of the arc line spectrum. As above.

QC Report 4 (spectral resolution and residuals):
top: the spectral resolution as a function of wavelength. The spectral resolution and its error is computed for each arc line detected by the pipeline. The median spectral resolution is shown as a blue dotted line with blue shading indicating the +/- 1 standard deviation range. The nominal spectral resolution (as given by the SINFONI User's Manual, pg. 65), for the given grism and pixel scale, is indicated by a thick green line. Both values are written to the top left of the plot.
center: the arc line residuals are computed from the positional differences between the computed arc line positions and the positions given by the reference arc line table. The residuals are plotted in units of pixels, and the median value is shown as a dotted blue line with blue shading indicating the +/- 1 standard deviation range.
bottom: the non-linear wavelength conversion terms. The non-linear terms are given by:
lambda(NL) = -(C2*x² + C3*x³) [where: x = y - (Ny-1)/2, and Ny is the number of y-axis pixels (2048)]. The blue line indicates the current non-linear terms, while the red line shows the non-linear terms of the reference wavelength solution.

A more technical description of the QC procedures used for the wavelength calibration can be found here.

Trending and Issues

The wavelength dispersion solution derived by the SINFONI pipeline and trended is intended for determining the instrument stability. It is a relatively low-order dispersion solution is based solely on a few detected arc lines. Users processing science data should use higher orders and include sky OH emission lines for higher accuracy dispersion solutions.

History

SINFONI grating wavelengths and resolutions are quite stable. The wavelength rms values are generally better than 2 Angstroem (worst case: 4 Angstroem in H+K) over entire observing semesters. Any slightly larger jumps are only seen following interventions. This can be seen in the full wavelength history and the full resolution history.