ISAAC: reduction of science data

ISAAC pipeline:
science data

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general

ISAAC

SCIENCE DATA: GENERAL

On Paranal, the quick-look pipeline makes an effort to automatically reduce all science data. The reduction is performed using standard calibration solutions from a local calibration database which is refreshed every few months. Generally any pipeline processing on the site is done on a best-effort basis. Its purpose is to offer a quick look to assess data quality etc.

At QC Garching, SCIENCE data taken in Service Mode are pipeline-reduced, using the best available calibration solutions (quality-checked and closest in time, following the calibration cascade). The products of science reduction are also quality-checked. If any irregularity in the reduced data is found, an attempt is made to improve on this. If not possible, information about the problem is made available in the data package. The general policy is to never suppress science data.

TYPES OF RAW SCIENCE DATA

ISAAC science raw data come in the following types:

frame	DPR TYPE	Description	typical number taken per OB and setting
SW-arm Imaging	OBJECT or SKY	The raw frames come as a stack of jittered OBJECT frames. SKY frames are optional	5-40
SW-arm Spectroscopy	OBJECT	The raw frames come as a stack of nodded and optionally jittered OBJECT frames.	2-10
SW-arm Polarimetry	OBJECT	as SW-arm imaging
LW-arm imaging	OBJECT or SKY	Jitter-mode: as LW-arm imaging	5-40
LW-arm imaging	OBJECT	Chopping mode: The raw frames come as a stack of OBJECT frames. The frames are data cubes; composed of two frames; each frame corresponds to a chopping position.	5-40
LW-arm Spectroscopy	OBJECT	Jitter mode: as SW-arm spectroscopy	2-10
LW-arm Spectroscopy	OBJECT	Chopping mode: The raw frames come as a stack of OBJECT frames. The frames are data cubes; composed of two frames; each frame corresponds to a chopping position.	2-10
LW-arm FastJitter	OBJECT	The raw frames are data cubes. The first two dimensions correspond to the detector window and the third dimension coresponds to the time. Several data cubes result form the repeated execution of the one science OB.	1-3
LW-arm Burst	OBJECT	The raw frames are data cubes. The first two dimensions correspond to the detector window and the third dimension corresponds to time. Several data cubes result form the repeated execution of the one science OB.	1-3

SCIENCE PRODUCTS

Overview of science recipe and QC plots

There is one pipeline recipe for science imaging modes isaac_img_jitter and one recipe for all science spectroscopy modes isaac_spc_jitter. The isaac_spc_jitter serves also calibrations spectra like those of telluric standard stars and flux calibration stars, meaning science and calibration star spectra follow essentially the same data reduction scheme.

raw frame(s)	product	description	PRO CATG keys of product FITS header
SW-imaging		Three products are generated: The coadded image stack, a sky background table and a table of the found sources.	COADDED_IMG SKY_TAB STARS_TAB
SW-spectroscopy		The co-added spectrum image and the extracted spectrum table	OBS_COMBINED OBS_EXTRACTED
SW-Polarimetry		not supported by the pipeline
LW-imaging		The coadded image and the source table	COADDED_IMG STARS_TAB
LW-spectroscopy		The co-added spectrum image and the extracted spectrum table	OBS_COMBINED OBS_EXTRACTED
LW-FastJitter		not supported by the pipeline
LW-Burst		not supported by the pipeline