We present analysis of Spitzer Space Telescope observations of the three low surface brightness (LSB) optical giant galaxies Malin 1, UGC 6614 and UGC 9024. Mid- and far-infrared morphology, spectral energy distributions, and integrated colors are used to derive the dust mass, dust-to-gas mass ratio, total infrared luminosity, and star formation rate (SFR). We also investigate UGC 6879, which is intermediate between high surface brightness (HSB) and LSB galaxies. The 8 µm images indicate that polycyclic aromatic hydrocarbon (PAH) molecules are present in the central regions of all three metal-poor LSB galaxies. The diffuse optical disks of Malin 1 and UGC 9024 remain undetected at mid- and far-infrared wavelengths. The dustiest of the three LSB galaxies, UGC 6614, has infrared morphology that varies significantly with wavelength; 160 µm (cool) dust emission is concentrated in two clumps on the NE and NW sides of a distinct ring seen in the 24 and 8 µm images (and a broken ring at 70 µm) at a radius of ∼40 ′ ′ (18 kpc) from the galaxy center. The 8 and 24 µm emission is co-spatial with Hα emission previously observed in the outer ring of UGC 6614. The estimated dust-to-gas ratios, from less than 10 −3 to 10 −2, support previous indications that the LSB galaxies are relatively dust poor compared to the HSB galaxies. The total infrared luminosities are approximately 1/3 to 1/2 the blue band luminosities, suggesting that old stellar populations are the primary source of dust heating in these LSB objects. The SFR estimated from the infrared data ranges ∼0.01 − 0.88 M ⊙ yr −1, consistent with results from optical studies
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