AAS 197, January 2001
Session 42. Dust and Theory of ISM
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

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[42.04] Infrared Emission from Interstellar Dust in the Diffuse ISM

B.T. Draine, Aigen Li (Princeton University Observatory)

We have extended the ``graphite-silicate'' grain model to explicitly include a PAH component as the small-size end of the carbonaceous grain population. With an appropriate abundance and size distribution for the PAH population, and size distributions of the larger graphite and silicate grains adjusted to reproduce the interstellar extinction curve (Weingartner & Draine 2001), the infrared emission spectrum -- including PAH features -- calculated for this grain model is in excellent quantitative agreement with observations of infrared emission from the diffuse interstellar medium (Li & Draine 2001). We compare the calculated infrared emission spectrum with COBE/DIRBE observations of infrared emission from the ISM at |b| > 20, and with observations by IRTS and COBE/DIRBE of emission from the galactic plane near l = 44, b = 0.

We calculate infrared emission spectra -- including PAH features -- for dust heated by a range of radiation fields, and have convolved these emission spectra with the SIRTF/IRAC and SIRTF/MIPS filter responses.

This research was supported by NASA grant NAG5-7030 and NSF grants AST-9619429 and AST-9988126.


Li, A., & Draine, B.T. 2001, ApJ, to be submitted.\\ Weingartner, J.C., & Draine, B.T. 2001, ApJ, 548, 000. (astro-ph/0008146)

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