Moderate-luminosity active galactic nuclei (AGN) are classified spectroscopically as Seyfert 1s or Seyfert 2s based on the detection (or lack thereof) of broad optical emission lines. Optical spectropolarimetry observations reveal that some Seyfert 2s exhibit polarized broad emission lines, implying that these objects contain Seyfert 1 nuclei hidden from direct view by an obscuring torus of dense matter. Thus, Seyfert 1s and Seyfert 2s may be a unified class of objects, differing only by the inclination of the torus with respect to our line of sight (Antonucci1993). However, hidden broad line regions (HBLRs) are detected in less than half of Seyfert 2s in polarimetry surveys, which has prompted arguments against apurely orientation-based AGN unification model. As one example, the Seyfert 2X-ray study by Marinucci et al. (2012) concluded that the presence of an HBLR is driven by the black hole accretion rate. However, this study utilized spectropolarimetry results from the literature and X-ray data in the 2-10 keV band, where the spectra of absorbed AGNs are especially complex. Thus, selection effects and uncertainties in the derived X-ray luminosities (and, therefore, accretion rates) of the objects may have been factors. To reexamine the role of accretion rate in AGN unification, we have analyzedNuSTAR3-79 keV data for a large, distance-limited sample of Seyfert 2s with sensitive spectropolarimetry observations.
"},{"label":"Degree","value":["Bachelor of Arts with Departmental Honors"]},{"label":"Author-supplied Keywords","value":["Extragalactic astronomy","Active galactic nuclei","X-ray astronomy"]},{"label":"Administrative Note","value":"Drupal Node ID: 24034