CASSISjuice [atlas]

Mid-infrared spectroscopy provides many important diagnostics on gas and dust features in a wide variety of astrophysical objects. In the JWST era, it is important to maintain a durable database of observations with previous facilities, for preparing new observations or completing existing ones. The Spitzer Infrared Spectrograph observed more than 20000 targets with wavelengths as low as 5.2um and as long as 38.0um, thereby complementing JWST/MIRI data for the long wavelength diagnostics and providing overall invaluable diagnostics together with JWST or in view of future IR facilities.

In order to maximize the science output of Spitzer/IRS, the CASSIS atlas has provided reduced IRS spectra since 2011, selecting the best spectrum from various methods. We present CASSISjuice, an offline version of the pipeline (https://zenodo.org/record/8339954) and atlas (https://zenodo.org/record/8339965), adding several hundred sources that had never cleared the pipeline in order to make it complete for the first time.

We updated the low- and high-resolution pipelines in order to be able to process every IRS staring mode observation (i.e., all observations but maps), and we also upgraded the high-resolution pipeline to version 2. The new pipeline also associates the pointings within ``cluster'' observations resulting in a single spectrum (possibly low- and high-resolution) per position and therefore overall a single CASSISjuice ID per targeted position. Independent observations at the same position are still not combined.

The repositories, available at Zenodo and https://gitlab.com/cassisjuice, provide the open-source pipeline code and the atlas itself with specific attention to producing the smallest dataset possible. Python notebooks are included to illustrate the offline manipulation of the full atlas. The offline CASSISjuice atlas is meant to facilitate the analysis of large samples and the identification of potentially interesting or relevant spectra.