SHIPsPhot

Purpose of this page:

• Provide photometry references for Herschel specific photometry

Aperture Photometry Parameters

Recommended Values for NGC 281

Filter	Aperture Radius (")	Inner Sky Radius (")	Outer Sky Radius (")	Aperture Correction	Pixels
70 microns	9.6	9.6	19.2	0.7331
100 microns	9.6	9.6	19.2	0.6944
160 microns	12.8	12.8	25.6	0.6602

Herschel/PACS optical properties

• PACS quick summary guide (BEWARE: arc-seconds vs pixels). SHIPs data is taken at 20"/sec scan speed. Take an average between the long and the short side of the PSF.

APT parameters

Values to use for APT photometry

Parameter/Setting	SHIPs value	Comments
Aperture Values	As in above table recomputed to pixels.
Select source algorithm	Model 0
Select sky algorithm	Model B
Use centroid in photometry calculation?	Yes. Box is checked.
Automatically snap aperture to centroid?	Yes. Box is checked.

Photometry Assignment

5 APT Practice Sources

The Big Picture

• Gather relevant and previously available photometry on NGC 281 (DONE, except Spitzer)
• Gather images from previous surveys (DONE)
• Herschel Images (DONE, but may be reprocessed)
• Aperture Photometry
• PSF photometry (Preliminary version, calibration missing).
• Check Aperture photometry for bad sources, missed sources.
• Create flags for all sources.
• Check Aperture vs. PSF photometry. Select one or the other for each protostar.
• Finalize Herschel photometry
• Merge all photometry.