Mathematics – Logic
Scientific paper
Jun 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006phdt.........5d&link_type=abstract
Proquest Dissertations And Theses 2006. Section 0167, Part 0606 250 pages; [Ph.D. dissertation].United States -- Ohio: Ohio Uni
Mathematics
Logic
1
Interstellar Medium, Elliptical Galaxies, Active Galactic Nuclei
Scientific paper
I present a complete morphological and spectral X-ray analysis of the hot interstellar medium in 54 normal elliptical galaxies in the Chandra archive. I isolate their hot gas component from the contaminating point source emission, and adaptively bin the gas maps with a new adaptive binning technique using weighted Voronoi tesselations. A comparison with optical images and photometry shows that the gas morphology has little in common with the starlight. In particular, I observe no correlation between optical and X-ray ellipticity, contrary to expectations for hydrostatic equilibrium.
Instead, I find that the gas in general appears to be very disturbed, and I statistically quantify the amount of asymmetry. I see no correlations with environment, but a strong dependence of asymmetry on radio and X-ray AGN luminosities, such that galaxies with more active AGN are more disturbed. Surprisingly, this AGN-morphology connection persists all the way down to the weakest AGN, providing strong morphological evidence for AGN feedback in normal elliptical galaxies. I conclude that the hot gas in elliptical galaxies is generally not in hydrostatic equilibrium; instead, it is continually disturbed by intermittent outbursts of the central AGN.
I extract radial temperature profiles, revealing surprisingly complex structures with positive and negative gradients, or even combinations of both. I find that the outer temperature gradient is determined by galaxy environment, while the inner temperature profiles shows a strong correlation with radio luminosity and a weaker with stellar mass. While our data are consistent with compressive heating in cooling flow models or supernova heating, AGN feedback is a more likely explanation. I suggest that the change of sign for the temperature gradient indicates either how localized different AGN heat, or where AGN heating becomes unimportant.
Despite the disturbed gas morphology, I also report on the discovery of a tight correlation, the X-ray gas fundamental plane (XGFP), linking temperature, half- light radius, and average surface brightness as T X 0( [Special characters omitted.] , reducing the large scatter in the closely related luminosity- temperature relation. The XGFP has a small intrinsic width of only 0.07 dex, and represents a new constraint on the hydrodynamic history of the gas.
No associations
LandOfFree
The hot interstellar medium in normal elliptical 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 The hot interstellar medium in normal elliptical galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The hot interstellar medium in normal elliptical galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1476594