Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

Details Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

Dec 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007aas...211.4404t&link_type=abstract

American Astronomical Society, AAS Meeting #211, #44.04; Bulletin of the American Astronomical Society, Vol. 39, p.792

Astronomy and Astrophysics

Astronomy

1

Scientific paper

Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars.
We acknowledge work supported by the NSF under grant number 0237291.

Affiliated with

Also associated with

No associations

Rating

Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1476719