Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies

Details Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies

1999-08-09

arxiv.org/abs/astro-ph/9908100v1

Astronomy and Astrophysics

Astrophysics

19 pages, 6 figures, uses AAS LaTeX; to appear in the November Astronomical Journal

Scientific paper

10.1086/301110

We report a mid-infrared color and surface brightness analysis of IC 10, NGC 1313, and NGC 6946, three of the nearby galaxies studied under the Infrared Space Observatory Key Project on Normal Galaxies. Images with < 9 arcsecond (170 pc) resolution of these nearly face-on, late-type galaxies were obtained using the LW2 (6.75 mu) and LW3 (15 mu) ISOCAM filters. Though their global I_nu(6.75 mu)/I_nu(15 mu) flux ratios are similar and typical of normal galaxies, they show distinct trends of this color ratio with mid-infrared surface brightness. We find that I_nu(6.75 mu)/I_nu(15 mu) ~< 1 only occurs for regions of intense heating activity where the continuum rises at 15 micron and where PAH destruction can play an important role. The shape of the color-surface brightness trend also appears to depend, to the second-order, on the hardness of the ionizing radiation. We discuss these findings in the context of a two-component model for the phases of the interstellar medium and suggest that star formation intensity is largely responsible for the mid-infrared surface brightness and colors within normal galaxies, whereas differences in dust column density are the primary drivers of variations in the mid-infrared surface brightness between the disks of normal galaxies.

Affiliated with

Also associated with

No associations

Rating

Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies 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 Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Towards an Understanding of the Mid-Infrared Surface Brightness of Normal Galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-201843