• Media type: E-Article
  • Title: Regrowth of stellar disks in mature galaxies: The two component nature of NGC 7217 revisited with VIRUS-W
  • Contributor: Fabricius, Maximilian H.; Coccato, Lodovico; Bender, Ralf; Drory, Niv; Gössl, Claus; Landriau, Martin; Saglia, Roberto P.; Thomas, Jens; Williams, Michael J.
  • imprint: Cambridge University Press (CUP), 2014
  • Published in: Proceedings of the International Astronomical Union
  • Language: English
  • DOI: 10.1017/s1743921314009363
  • ISSN: 1743-9213; 1743-9221
  • Keywords: Astronomy and Astrophysics ; Space and Planetary Science
  • Origination:
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  • Description: <jats:title>Abstract</jats:title><jats:p>We have obtained high spectral resolution (<jats:italic>R</jats:italic> ≈ 9000), integral field observations of the three spiral galaxies NGC 3521, NGC 7217 and NGC 7331 using the new fiber-based Integral Field Unit instrument VIRUS-W at the 2.7 m telescope of the McDonald Observatory in Texas. Our data allow us to revisit previous claims of counter rotation in these objects. A detailed kinematic decomposition of NGC 7217 shows that no counter rotating stellar component is present. We find that NGC 7217 hosts a low dispersion, rotating disk that is embedded in a high velocity dispersion stellar halo or bulge that is co-rotating with the disk. Due to the very different velocity dispersions (≈ 20 km s<jats:sup>−1</jats:sup> vs. 150 km s<jats:sup>−1</jats:sup>) , we are further able to perform a Lick index analysis on both components separately which indicates that the two stellar populations are clearly separated in (Mg<jats:italic>b</jats:italic>,〈Fe〉) space. The velocities and dispersions of the faster component are very similar to those of the interstellar gas as measured from the [O <jats:sc>iii</jats:sc>] emission. Morphological evidence of active star formation in this component further suggests that NGC 7217 may be in the process of (re)growing a disk inside a more massive and higher dispersion stellar halo.</jats:p>