CASCADe and HST dataΒΆ
The CASCADe package comes with the functionality to download data from the
HST data archive (MAST), and simultaneously generate the correct .ini
files
and pipeline scripts. files. To make use of this functionality, the user can make
use of the build_local_hst_archive.py
python script. This script makes use of the
WFC_files.pickle
database file which can be found in the archive_databases
sub-directory of the main CASCADe storage directory as defined by the
CASCADE_STORAGE_PATH
environment variable. This data base file contains most
spectroscopic transit observations made with the HST WFC3 instrument. In this file,
for each visit, the data files belonging to that visit are defined, together with
the main instrument settings. To get an overview of the main functionality one can
execute of the command line the following command:
build_local_hst_archive.py --help
which will print all options available with this python script. To list all planets for which an HST data set is defined in the database file, one can use the following command:
build_local_hst_archive.py -lap
which will print a list of all available planets. One can then pick a planet and download all data from the MAST archive. As an example, for the data of WASP-117b, as published in Carone et al 2021 one can execute the folowing command:
build_local_hst_archive.py -avp WASP-117b
which will download all the spectroscopic data for this planet. In this case the
ima data product is downloaded as it is a spatial scanning observation,
together with several target acquisition images, for which we use the flt data
product. In addition to downloading the data, also the required initialization
files are generated, which will be written to the directory specified by the
CASCADE_INITIALIZATION_FILE_PATH
environment variable. for generating the
initialization files, CASCADe makes use of the processing_exceptions.ini
file which can be found in the archive_databases
sub directory where also the
database file is located. This file contains several predefined values for most
observations in the database which we found to be optimal, or where derived in
published studies. The user has the possibility to overwrite these values by
creating a user_processing_exceptions.ini
file and define any initialization
parameter value in there in a similar manner as is done in the
processing_exceptions.ini
file. If an observation has no entry in one of
these files, standard values are used from one of the exoplanet archives and from
the fits headers of the data files.
Finally, also an command line pipeline execution script is generated and stored
in the directory defined by the CASCADE_SCRIPTS_PATH
environment variable.
Executing that script will run the entire CASCADe pipline, extracting the
spectral time series from the spectral images or cubes and fit the transit signal
to derive the planetary spectrum.