K. D. Gordon

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Context. Constraints on the origin and propagation of cosmic rays can be achieved by studying the variation in the spectral index of the synchrotron emission across external galaxies. Aims. To determine the variation in the nonthermal radio spectral index in the nearby spiral galaxy M33 at a linear resolution of 360 pc. Methods. We separate the thermal and(More)
The Multiband Imaging Photometer for Spitzer (MIPS) provides long-wavelength capability for the mission in imaging bands at 24, 70, and 160 m and measurements of spectral energy distributions between 52 and 100 m at a spectral resolution of about 7%. By using true detector arrays in each band, it provides both critical sampling of the Spitzer point-spread(More)
Physical dust models are presented for 65 galaxies in the SINGS survey that are strongly detected in the four IRAC bands and three MIPS bands. For each galaxy we estimate (1) the total dust mass, (2) the fraction of the dust mass contributed by PAHs, and (3) the intensity of the starlight heating the dust grains. We find that spiral galaxies have dust(More)
The absolute calibration and characterization of the Multiband Imaging Photometer for Spitzer (MIPS) 70 μm coarseand fine-scale imaging modes are presented based on over 2.5 years of observations. Accurate photometry (especially for faint sources) requires two simple processing steps beyond the standard data reduction to remove long-term detector(More)
We present Spitzer Space Telescope early release observations of Fomalhaut, a nearby A-type star with dusty circumstellar debris. The disk is spatially resolved at 24, 70, and 160 m using the Multiband Imaging Photometer for Spitzer (MIPS). While the disk orientation and outer radius are comparable to values measured in the submillimeter, the disk inner(More)
Pitting or bubbling on the surface of epoxy resin replicas is a frequently encountered artefact associated with the use of silicone rubber impression materials. Several variants of this type of artefact are illustrated. It is suggested that bubbles or pits form at the mould:epoxy interface during curing of the epoxy, and that they are caused by gas escaping(More)
Galaxy source counts in the infrared provide strong constraints on the evolution of the bolometric energy output from distant galaxy populations. We present the results from deep 24 m imaging from Spitzer surveys, which include 5 ;10 sources to an 80% completeness of ’60 Jy. The 24 m counts rapidly rise at near-Euclidean rates down to 5 mJy, increase with a(More)
We present an exhaustive, quantitative comparison of all of the known extinction curves in the Small and Large Magellanic Clouds (LMC and SMC) with our understanding of the general behavior of Milky Way extinction curves. The RV dependent CCM relationship and the sample of extinction curves used to derive this relationship is used to describe the general(More)
We report the discovery of a debris system associated with the ∼ 30 Myr old G3/5V star HD 12039 using Spitzer Space Telescope observations from 3.6 – 160μm. An observed infrared excess (LIR/L∗ = 1 × 10 ) above the expected photosphere for λ & 14μm is fit by thermally emitting material with a color temperature of T∼ 110 K, warmer than the majority of debris(More)
We have obtained Spitzer Space Telescope MIPS observations of 40 Fand G-type common proper motion members of the Scorpius-Centaurus OB Association with ages between 5 and 20 Myr at 24 μm and 70 μm. We report the detection of fourteen objects which possess 24 μm fluxes ≥30% larger than their predicted photospheres, tentatively corresponding to a disk(More)