reduced using a near-standard pipeline with the Herschel Interactive Processing Environment [HIPE Version 7.0, @2010ASPC..434..139O]. We decrease the noise slightly by including some data taken as the telescope is accelerating and decelerating at the start and end of each scan leg.

The high level of redundancy provided by PACS scan maps means that the pixel size used to generate maps can be smaller than the natural scale of 3.2”/pix at 70 and 100$\mu$m and 6.4”/pix at 160$\mu$m via an implementation of the “drizzle” method [@2002PASP..114..144F]. Our maps are generated at 1”/pix at 70 and 100$\mu$m and 2”/pix at 160$\mu$m. The benefit of better image sampling comes at the cost of correlated noise [@2002PASP..114..144F], which we discuss below.

In addition to correlated noise, two characteristics of the PACS instrument combine to make interpretation of the data challenging. The PACS beam has significant power at large angular scales; about 10% of the energy lies beyond 1 arcminute and the beam extends to about 17 arcminutes (1000 arcsec). While this extent is not a problem in itself, it becomes problematic because PACS data are subject to fairly strong $1/f$ (low frequency) noise and must be high-pass filtered. The result is that a source 