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Date and Time of the Query: 2019-08-20 T21:59:54 PDT
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For refcode 2007ApJ...660.1215T:
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Copyright by American Astronomical Society. Reproduced by permission
2007ApJ...660.1215T Far-Infrared Spitzer Observations of Elliptical Galaxies: Evidence for Extended Diffuse Dust Pasquale Temi, Fabrizio Brighenti, and William G. Mathews Abstract. Far-infrared Spitzer observations of elliptical galaxies are inconsistent with simple steady state models of dust creation in red giant stars and destruction by grain sputtering in the hot interstellar gas at T~10^7^ K. The flux at 24 micron correlates with optical fluxes, suggesting that this relatively hot dust is largely circumstellar. But fluxes at 70 and 160 micron do not correlate with optical fluxes. Elliptical galaxies with similar L_B_ have luminosities at 70 and 160 micron (L_70_ and L_160_) that vary over a factor of ~100, implying an additional source of dust unrelated to that produced by ongoing local stellar mass loss. Neither L_70_/L_B_ nor L_160_/L_B_ correlate with the stellar age or metallicity. Optical line fluxes from warm gas at T~10^4^ K correlate weakly with L_70_ and L_160_, suggesting that the dust may be responsible for cooling this gas. Many normal elliptical galaxies have emission at 70 micron that is extended to 5 -- 10 kpc. Extended far-infrared emission with sputtering lifetimes of ~10^8^ yr is difficult to maintain by mergers with gas-rich galaxies. Instead, we propose that this cold dust is buoyantly transported from reservoirs of dust in the galactic cores, which are supplied by mass loss from stars in the core. Intermittent energy outbursts from AGNs can drive the buoyant outflow. Key words: Galaxies: Elliptical and Lenticular, cD, Galaxies: ISM, Infrared: Galaxies, Infrared: ISM
Retrieve 46 NED objects in this reference.
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