High-Resolution Far Infrared Images of Centaurus A

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Session 80 -- AGN and Jets

[80.06] High-Resolution Far Infrared Images of Centaurus A

R. LeWinter (Wesleyan U.), M. Rupen (NRAO), Z. Wang (CfA)

We present high-resolution images of Centaurus~A at 12, 25, 60, and $100\mu$m, created using the HiRes algorithm from the IRAS survey data. The resulting resolution varies between $1\times0.5$ ($12\mu$m) and $2\times1.5$arcmin ($100\mu$m). The dust emission clearly follows the optical dust lane and the neutral hydrogen distribution; we detect for the first time at far infrared (FIR) wavelengths the outer warp, and there is some indication of a ``halo'' of cold dust emitting outside the disk. While the $12/25\mu$m colour is virtually constant across the galaxy, the $60/100\mu$m colour temperatures increase from 28K near the edge to 40K at the center of the disk, consistent with other evidence for massive star formation near the nucleus. Comparison with atomic (HI) and molecular (CO) observations shows that the FIR emission tracks the sum of both rather than the individual gaseous components, both in general trends (radial decline, warping) and specific features (asymmetry to the east, possible southern extension near the center). There is no obvious correspondence between the FIR and radio morphologies, which is not surprising given the dominance of the central AGN and large-scale jet at radio wavelengths. If the disk of CenA follows the far infrared/radio correlation observed in spiral galaxies, radio images with dynamic ranges of $>5000$-to-1 will be required to detect its radio emission.

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