Extended narrow-line emission in the bright Seyfert 1.5 galaxy HE
  2211-3903
  Extended narrow-line regions (ENLRs) and extended emission-line regions
(EELRs) have been the focus of integral field spectroscopy aiming at the inner
kiloparsecs of nearby Seyfert galaxies as well as the larger environment of
high redshift QSOs. Based on observations with the Wide Field Spectrograph
WiFeS at the 2.3 m telescope of the Australian National University, we present
spatially resolved emission-line diagnostics of the bright Seyfert 1.5 galaxy
HE 2211-3903 which is drawn from a sample of the brightest Seyfert galaxies at
z<0.06 with luminosities around the classical Seyfert/QSO demarcation. In
addition to the previously known spiral arms of HE 2211-3903, the emission-line
maps reveal a large scale ring with a radius of about 6 kpc which is connected
to the active galactic nucleus (AGN) through a bar-like structure. The overall
gas kinematics indicates a disk rotation pattern. The emission-line ratios show
Seyfert-type, HII region-type, and composite classifications, while there is no
strong evidence of LINER-type ratios. Shock ionization is likely to be
negligible throughout the galaxy. The composite line ratios are explained via a
mixing line between AGN and HII region photoionization. Composite line ratios
are predominantly found in between the HII regions in the circum-nuclear
region, the bar-like structure to the east of the nucleus, and the eastern half
of the ring, suggesting AGN photoionization of the low-density interstellar
medium in an ENLR on galaxy scales. The line ratios in the nucleus indicate
N-enrichment, which is discussed in terms of chemical enrichment by Wolf-Rayet
and Asymptotic Giant Branch stars during past and ongoing nuclear starburst
activity.
