Herschel Orion Protostar Survey PACS README

The targets, identified by a unique HOPS number, were observed in various groups using the PACS instrument on Herschel in scan mode; each group's observations are specified in two AORs, one for the scan and one for the cross-scan. Each group was observed using the 70 and 160 micron filter on PACS. Some groups contain a large number of HOPS targets, while others encompass very few.

Delivered maps for each group were reduced with two different mappers: (1) high-pass filter with photProject and (2) scanamorphos. These are the files ending in "HPF_PACS70.fits", "HPF_PACS160.fits", "scanamorphos_PACS70.fits", and "scanamorphos_PACS160.fits". For most groups the source masks used for the high-pass filter were also delivered; these are the files ending in "PACS70_mask.fits" and "PACS160_mask.fits". Thus, each group has 4-6 files associated with it.

Each fits file that contains either "HPF" or "scanamorphos" in its file name has three extensions: the first one is the signal map (in Jy/pixel), the second is the error map (in Jy/pixel), and the third one is the coverage map. The main header of each fits file contains information on the telescope, instrument, target, pointing, observing times, data products, and the OTKP proposal.

Recommended usage: the HPF products for aperture photometry, the scanamorphos products for PSF photometry. HPF filters out low-frequency signals in a way that preserves point sources, but might introduce artifacts in the extended emission. To analyze extended emission in the PACS maps, it is best to use the scanamorphos products.