Examples of multiwavelength images of NGC 3521 used for aperture photometry and SED construction: (a) GALEX NUV; (b) SDSS g band; (c) Herschel/PACS 160 μm; and (d) VLA L-band radio continuum. All panels show the same field of view (570″ × 570″) centered on the galaxy; the axes are angular offsets from the center in arcseconds. The color-scales are shown in commonly used map units, as labeled on each color-bar. For GALEX NUV, we converted the count-rate map to a band-integrated flux per pixel in erg cm⁻² s⁻¹ pix⁻¹ using the standard GALEX photometric calibration and the effective band pass width; for the SDSS g-band, we display flux density per pixel (nanomaggies/pix); for PACS 160 μm, the map is shown in Jy/pix, and for the VLA L-band in Jy/beam. The pixel scale (and, for the VLA map, the beam size BMAJ × BMIN) is indicated in each image. To preserve faint emission while avoiding saturation in bright regions, all images are displayed with an inverse-hyperbolic-sine (asinh) stretch. The red ellipse marks the adopted isophotal aperture used for integrated flux measurements.