We present 70 and 160 m observations from the Spitzer extragalactic First Look Survey (xFLS). The data reduction techniques and the methods for producing co-added mosaics and source catalogs are discussed. Currently, 26% of the 70 m sample and 49% of the 160 m-selected sources have redshifts. The majority of sources with redshifts are star-forming galaxies at z < 0:5, while about 5% have infrared colors consistent with active galactic nuclei. The observed infrared colors agree with the spectral energy distributions (SEDs) of local galaxies previously determined from IRAS and Infrared Space Observatory data. The average 160 m/70 m color temperature for the dust is T d ' 30 AE 5 K, and the average 70 m/24 m spectral index is ' 2:4 AE 0:4. The observed infrared-to-radio correlation varies with redshift as expected out to z $ 1 based on the SEDs of local galaxies. The xFLS number counts at 70 and 160 m are consistent within uncertainties with the models of galaxy evolution, but there are indications that the current models may require slight modifications. Deeper 70 m observations are needed to constrain the models, and redshifts for the faint sources are required to measure the evolution of the infrared luminosity function.

We present 12 CO(J=1-0) observations in the direction of the Soft Gamma Repeater SGR 1806-20 with the SEST telescope. We detected several molecular clouds, and we discuss in this paper the implications of these observations for the distance to the X-ray counterpart AX 1805.7-2025, the supernova remnant G10.0-0.3 and the very luminous O9-B2 star detected in the line of sight. The distance of SGR 1806-20 is estimated to be 14.5 ± 1.4 kpc and this Soft Gamma Repeater is very likely associated with one of the brightest HII regions in the Galaxy, W31. The large size of G10.0-0.3 (25 × 38 pc) for a young supernova remnant possibly powered by a central pulsar (AX 1805.7-2025) indicates that G10.0-0.3 could be expanding in the very low density region produced by the wind of the blue star.

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The multiwavelength spectra of PKS 0528+134 during six years of observations by EGRET have been analyzed using synchrotron self-Compton (SSC) and external radiation Compton (ERC) models. We find that a two-component model, in which the target photons are produced externally to the gamma-ray emitting region, but also including an SSC component, is required to suitably reproduce the spectral energy distributions of the source. Our analysis indicates that there is a trend in the observed properties of PKS 0528+134, as the source goes from a gamma-ray low state to a flaring state. We observe that during the higher gamma-ray states, the bulk Lorentz factor of the jet increases and the ERC component dominates the high-energy emission. Our model calculations indicate the trend that the energies of the electrons giving rise to the synchrotron peak decreases, and the power-ratio of the gamma-ray and low energy spectral components increases, as the source goes from a low to a high gamma-ray state.

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