Notes on ComaLS data in Astro-WISE

Below are some notes on formats and content of the ComaLS data present in the Astro-WISE system. Any data in the Astro-WISE can be viewed with the Databaseviewer. For the ComLS data convenient shortcuts are given here. The notes below discuss mostly these shortcuts. If you have any further questions please contact Gijs Verdoes or John Mcfarland (see NOVA-OmegaCEN Persons page). If you want to become more familiar with the Astro-WISE system: the Manual and HOW-TOs are a good starting point.

ReducedScienceFrames: Astro-WISE vs HST format

The ComaLS ACS Multi-Drizzled images coming out of the COMA LS dedicated calibration pipeline are stored in the Astro-WISE research environment. The drizzled frames are constructing using effective exposure time weighting. (For COMA-LS team members: they are the '*W_drz_cl.fits' files.) In Astro-WISE speak they are in the form of CoaddedRegriddedFrames, but are ingested at the ReducedScienceFrame level. This is because the regridding done by the Multi-Drizzle software was not done to the same grid as used by Astro-WISE. The ReducedScienceFrames of the ingested data can be regridded to this grid to allow coadding with other data in Astro-WISE. The format of ReducedScienceFrame is close to the format of the original *drz*fits files. The pixel values in the ReducedScienceFrame are identical to the [SCI] fits extension of the Multi-Drizzled images. The [WHT] fits extension, i.e., the weight frame, is stored as a separate WeightFrame and is linked to its RedudcedScienceFrame. The pixel values in this WeightFrame are divided by the exposure time as given by the header keyword EXPTIME in the *drz.fits file. By storing the data in these common Astro-WISE formats, one can make use of the Astro-WISE system capabilities for the ACS ComaLS data. One example Astro-WISE capability is that all analysis results (e.g., GALFIT and GALPHOT fits) are linked to the pixel data from which they were derived. This way one can easily inspect the goodness of fit of different runs of GALFIT and GALPHOT and how that depends on the settings of the fitting algorithm.

NOTE: ACS data ingestion currently only supports the Multi-Drizzled images. Raw data should be supported also, but its ingestion has not been tested. When requesting data from MAST, choose calibrated data to get only the Multi-Drizzle data.


SourceLists are made by SExtractor. Sextractor is run inside the Astro-WISE system. Information on how the sourcelist was derived (e.g., the SExtractor configuration used) can be viewed by clicking on the objectview link in the last column on the query page. You can store a sourcelist locally by selecting one (done by clicking on its number in the SLID column on the query form) and then using the "export-options" at the bottom end of the webpage. Make sure you set the "max number of rows" in the query form to "rownum" if you want to store all rows, i.e., all sources, in the sourcelist.