Vis Analysis Results Product

$SetSchemaPath vis/euc-vis-AnalysisResults.xsd

Data product name

$PrintDataProductName

Data product custodian

$PrintDataProductCustodian

Name of the Schema file

$PrintSchemaFilename

Last Edited for DPDD Version

1.1

Processing Element(s) creating/using the data product

VIS_science_xml_out

Processing function using the data product

VIS

Proposed for inclusion in EAS/SAS

Yes

Data product elements

$PrintDataProductElements

Detailed description of the data product

The analysis results is a .json file combining all the data quality control created during the processing of the image. This is very useful for determining which data is really usable for science and which not.

Description of some quality control

FPA.zero_point: VIS zero point calculated by comparison with Gaia data.

FPA.zp_rms: Standard deviation of the VIS zero point.

Check guiding

FPA.spreadmodel_peak: It is the peak of the spread model corresponding to the star in the flux_auto vs spread_model for \(1.5 <\) log10( FLUX_AUTO/FLUXERR_AUTO) \(< 2.5\). It is a good indicator of the quality of the guidance. We have estimated that spread model peak above 0.002 correspond to data with guiding errors.

The FPA.spreadmodel_sigma is standard deviation of the gaussian fit of the histogram of SExtractor spread model values.

Check X-Rays

For check if the data is contaminated by X-rays, we compute the ratio of cosmic rays detection by LA Cosmicx.

For the moment, we have determine that data with a number of cosmic rays above 2.1% for a nominal exposition is data that cannot be used. For normalise to the exposure time, we also need to add the readout time (70 s) for taking account that cosmics rays can arrive also during this time. In the fact, this type of data can be used with caution due to the fact that the X-rays affect only some quadrant and not all the FPA. Above this threshold, a lot of cosmic rays can be missed by LA Cosmicx.

We save the ratio of pixel with the flag COSMIC per detector in ccd.cosmic_pixel_ratio.

We calculate the maximum and the mean of this ratio per detector and stored it in this 2 indicatore :

FPA.max_cosmic_ratio: These correspond to the maximum ratio of pixels with the COSMIC flag in the FPA. If this indicator is high it may indicate an X-Rays pattern.

FPA.cosmic_pixel_ratio: These correspond to the mean ratio of pixels with the COSMIC flag in the FPA. This may indicate a proton shower.

Check straylight

For check if the data are affected by the straylight, you can compute the standard deviation of the mean background in the FPA. This is a good proxy but notice that a high standard deviation can be caused by a large object in the data.

Data is rejected if the standard deviation of the background in second is above 0.004.

The mean background in ADU of each CCD is reported in ccd.avg_bkg.