[87.04] The Central Concentration of PAH emission and Stellar Light Profiles: The Smoking Gun for Secular Evolution

AAS 207th Meeting, 8-12 January 2006
Session 87 Galaxy Structure and Evolution
Oral, Tuesday, 10:00-11:30am, January 10, 2006, Delaware B

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[87.04] The Central Concentration of PAH emission and Stellar Light Profiles: The Smoking Gun for Secular Evolution

M. W. Regan (STScI), M. D. Thornley (Bucknell), S. N. Vogel (Univ. of MD), K. Sheth (SSC), B. T. Draine (Princeton), M. Meyer (STScI), D. J. Hollenbach (NASA ARC), SINGS Team

Secular evolution of spiral galaxies requires the inflow of gas to small radii. If the inflow rate is faster than the rate of star formation, a central concentration of gas will form. The stars that form out of this gas will create a pseudobulge. Until now both the central concentrations of ISM and stellar pseudobulges have been observed but not in the same galaxy. In this talk I will compare the distribution of 8 micron PAH emission and the stellar light profiles of a sample of galaxies from SINGS. I will show that galaxies with large central concentrations of 8 micron PAH emission also show a pseudobulge type central light profile. In addition, galaxies that do not have a central concentration of 8 micron. emission have a more classical bulge light profile. These results show the first direct connection between the ISM and pseudo-bulges expected for secular evolution.

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