KECK Spectropolarimetry of High Redshift Radio Galaxies

  • A. Cimatti
  • A. Dey
  • W. van Breugel
  • R. Antonucci
  • H. Spinrad
Conference paper
Part of the International Astronomical Union book series (IAUS, volume 175)

Abstract

High redshift radio galaxies (HzRGs) are observable up to cosmological distances competitive with the most distant quasars. However, before using them as probes of galaxy evolution, it is crucial to separate the stellar and non-stellar components. One of the most striking properties of HzRGs is the alignment of the UV continuum with the axis of the radio source (alignment effect; McCarthy et al. 1987). However, the relative importance of the stellar and non-stellar radiation to the alignment effect is still unknown, although a significant fraction is recognized to come from scattering of anisotropic radiation emitted by the obscured nucleus, as expected in the unified model of powerful radio sources (di Serego Alighieri, Cimatti & Fosbury 1994). Spectropolarimetry is the most powerful technique to observe at the same time different radiation components, but the 4m class telescopes can reach a sufficient S/N ratio only on the few brightest objects. Therefore, in order to investigate the origin of the alignment effect and to test the validity of the unified model of powerful radio-loud AGN, we have started a program of optical spectropolarimetry of HzRGs with the W.M. Keck 10m telescope equipped with the Low Resolution Imaging Spectrometer (LRIS) in polarimetric mode.

Keywords

Radio Source Bright Object Galaxy Evolution Alignment Effect Extragalactic Radio Source 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© International Astronomical Union 1996

Authors and Affiliations

  • A. Cimatti
    • 1
    • 4
  • A. Dey
    • 1
  • W. van Breugel
    • 1
  • R. Antonucci
    • 2
  • H. Spinrad
    • 3
  1. 1.Institute of Geophysics and Planetary PhysicsLivermoreUSA
  2. 2.Physics DeptUniversity of California at Santa BarbaraUSA
  3. 3.Astronomy Dept.University of California at BerkeleyBerkeleyUSA
  4. 4.Osservatorio Astrofiscio di ArcetriItaly

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