Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-07-23
Astron.J.134:2086-2097,2007
Astronomy and Astrophysics
Astrophysics
20 pages, 11 figures; AJ, accepted; full resolution version available at http://spider.ipac.caltech.edu/staff/jhhowell/astro/h
Scientific paper
10.1086/521821
We present a study of the nearby Seyfert galaxy NGC 1068 using mid- and far- infrared data acquired with the IRAC, IRS, and MIPS instruments aboard the Spitzer Space Telescope. The images show extensive 8 um and 24 um emission coinciding with star formation in the inner spiral approximately 15" (1 kpc) from the nucleus, and a bright complex of star formation 47" (3 kpc) SW of the nucleus. The brightest 8 um PAH emission regions coincide remarkably well with knots observed in an Halpha image. Strong PAH features at 6.2, 7.7, 8.6, and 11.3 um are detected in IRS spectra measured at numerous locations inside, within, and outside the inner spiral. The IRAC colors and IRS spectra of these regions rule out dust heated by the AGN as the primary emission source; the SEDs are dominated by starlight and PAH emission. The equivalent widths and flux ratios of the PAH features in the inner spiral are generally consistent with conditions in a typical spiral galaxy ISM. Interior to the inner spiral, the influence of the AGN on the ISM is evident via PAH flux ratios indicative of a higher ionization parameter and a significantly smaller mean equivalent width than observed in the inner spiral. The brightest 8 and 24 um emission peaks in the disk of the galaxy, even at distances beyond the inner spiral, are located within the ionization cones traced by [O III]/Hbeta, and they are also remarkably well aligned with the axis of the radio jets. Although it is possible that radiation from the AGN may directly enhance PAH excitation or trigger the formation of OB stars that subsequently excite PAH emission at these locations in the inner spiral, the orientation of collimated radiation from the AGN and star formation knots in the inner spiral could be coincidental. (abridged)
Appleton Phil N.
Armus Lee
Bothun Greg
Chan Ben H. P.
Evans Aaron S.
No associations
LandOfFree
Tracing PAHs and Warm Dust Emission in the Seyfert Galaxy NGC 1068 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 Tracing PAHs and Warm Dust Emission in the Seyfert Galaxy NGC 1068, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tracing PAHs and Warm Dust Emission in the Seyfert Galaxy NGC 1068 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-110139