Smart Optimal Extraction ("Adopt" package)

Smart includes an extraction algorithm based on the use of point spread functions (PSFs) to find the flux of point-like sources. This method is effectively an optimal extraction and significantly increases the signal-to-noise ratio of the spectrum. It is available for the low-resolution modules SL and LL and it is best suited for faint targets.

Details on the algorithm can be found in Lebouteiller, Bernard-Salas, Sloan & Barry, arxiv0910.1846: "Advanced Optimal Extraction for Spitzer/IRS"

Associated calibration files are provided for pipeline versions s17.2 and s18.7. Data from s15.3 will be extracted with s17.2 calibration files. Earlier pipeline versions are not supported by Smart-Adopt.

The most important new possibilities enabled by the Smart Adopt package are:

• Optimal extraction of faint sources with significantly better S/N as compared to the regular Smart Tapered extraction
• Removal of complex backgrounds on-the-fly
• Optimal extraction of multiple sources in the slit, even blended
• Optimal extraction and reliable flux calibration of sources offset in the dispersion direction
• Finding sources with an accuracy of less than a fiftieth of pixel
• Estimating the spatial extent of sources
• Possibility to use the 2 nod information to better sample the spectrum
• Plot the aperture on the sky along with extracted sources, SIMBAD and NED objects, DSS and 2MASS images

Possible applications are:

• Disentangle blended sources in crowded environments
• Disentangle a point-like source within an extended source
• Accurate line measurements / line deblending using the improved sampling enabled by the special "optimal 2 nods extraction"

The following links explain how to use the Adopt package within Smart:

• Optimal extraction options
• How to call the optimal extraction interface from Smart
• Description of the GUI
• Optimal extraction cookbook
• How to script optimal extraction
• Main differences between optimal extraction in SMART and SPICE