The unified model of Seyfert 1 and Seyfert 2 galaxies proposes that they are a single population whose nuclei are viewed at different orientations. However, differences have been found between the properties of type 1 and 2 Seyferts that are inconsistent with simple unification. In some Seyfert 2 galaxies the broad-line region seen in Seyfert 1s may thus have disappeared, which simulations show will happen at very low accretion rates onto the central black hole. Such low accretion rates may be accompanied by declining star formation rates in the host galaxy. We propose to investigate this possibility through a multiwavelength study of the global star formation rates and kiloparsec-scale structure of 42 bright, nearby Seyfert galaxies selected from the Palomar spectral survey. High-quality 2 - 10 keV X-ray spectra of this sample have recently been obtained by XMM-Newton, with associated constraints on the nuclear accretion rates. The deep (~ 10 kilosec) and wide (24 arcmin) near-UV images of the objects obtained concurrently by the XMM-Optical Monitor telescope offer an unprecedented opportunity to measure the strength and distribution of their star formation, and will be the foundation of our study. We will combine these data with GALEX, Spitzer, HST, Chandra, optical, 2MASS, and radio observations to clarify the links between the emission at the respective wavelengths. We will specifically measure and compare the global star formation rates from the near-UV and Spitzer 24 micron images using current calibrations, and quantify the galaxies' structure in each band using a variety of methods including 2-D decomposition and the CAS and Gini parameters. We will then perform correlation tests between the measured parameters, including the nuclear accretion rates and global star formation rates, and test for differences between the Seyfert 1 and Seyfert 2 subsamples. The distribution of star formation revealed in the UV and Spitzer images will also provide a probe of feedback processes from nuclear outflows when combined with Chandra X-ray and radio images. In addition to the proposed analysis, we will produce a web-based public atlas of the images and relevant measured quantities to facilitate their future use. This project addresses the NASA ADP goals of understanding the origin and evolution of galaxies and phenomena associated with black holes.
|Effective start/end date||1/1/10 → 12/31/12|
- NASA: Goddard Space Flight Center: $328,277.00