Far-IR grayscale image in both a) and b) is observed with the Photodetector Array Camera and Spectrometer (PACS; Poglitsch et al. 2010) instrument at 70 μm obtained with Herschel as part of the HOBYS guaranteed time key program (PI: KPGT_fmotte_1, Motte et al. 2012). It is overlaid with the contours (red) of the 2 cm free-free continuum emission observed by Sewilo et al. (2004). For the λ = 2 cm continuum image the contour levels are at –3, 3, 5, 10, 20, 30, 40, 80, 120, 180, 250, 350, 450, 600, 800, and 850 times the noise level of 0.3 mJy beam^-1. The pixel scale of the Herschel-PACS image is 3.2″. The beam size of 5.2″ × 5.6″ for the 70 μm image and 0.48″ × 0.41″ for the 2 cm contour emission are illustrated in the lower left corner. The green, magenta and cyan circles illustrate the 36″, 17″ and 12″Herschel half power beam width, at the respective frequencies 572 GHz, 1214 GHz and 1764 GHz. The circles in dashed black and yellow illustrate the model radii R_max and R_ph, respectively.