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Morphological Evolution in High‐Redshift Radio Galaxies and the Formation of Giant Elliptical Galaxies
Morphological Evolution in High‐Redshift Radio Galaxies and the Formation of Giant Elliptical Galaxies
- Source :
- The Astrophysical Journal. 502:614-629
- Publication Year :
- 1998
- Publisher :
- American Astronomical Society, 1998.
-
Abstract
- We present deep near-IR images of high redshift radio galaxies obtained with NIRC on the Keck I telescope. In most cases, the near-IR data sample rest wavelengths at ~4000 Angstroms, free of strong emission lines. At z > 3, the rest frame optical morphologies generally have faint, large-scale emission surrounding multiple components of ~10 kpc size. The brightest of the small knots are often aligned with the radio structures. At z < 3, the morphologies change dramatically, showing single, compact structures without radio-aligned features. The sizes and luminosities of the individual components in the z > 3 radio galaxies are similar to those of the radio-quiet star-forming galaxies discovered at z ~ 3 by the Lyman dropout technique. The rest frame optical colors of the z > 3 radio galaxies are consistent with models in which recent star formation dominates the observed IR light, and in one case (4C 41.17) we have direct spectroscopic evidence for massive star formation (Dey et al. 1997a). Our results suggest that the z > 3 radio galaxies evolve into very massive elliptical galaxies at 2 < z < 3, in qualitative agreement with the hierarchical model of galaxy formation. We also discuss the Hubble diagram of radio galaxies, the possibility of a radio power dependence in the K-z relation, and the implications for radio galaxy formation.<br />Accepted for publication in The Astrophysical Journal; 34 pages including 8 postscript figures; plates 1-4 may be obtained from ftp://bigz.berkeley.edu/pub/nirc/
- Subjects :
- Physics
Radio galaxy
Star formation
Astrophysics::High Energy Astrophysical Phenomena
Astrophysics (astro-ph)
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Galaxy
Redshift
law.invention
Telescope
Space and Planetary Science
law
Galaxy formation and evolution
Elliptical galaxy
Astrophysics::Solar and Stellar Astrophysics
Emission spectrum
Astrophysics::Galaxy Astrophysics
Subjects
Details
- ISSN :
- 15384357 and 0004637X
- Volume :
- 502
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....c4b2dffee4c7107dbb9fcb27ff2cc741
- Full Text :
- https://doi.org/10.1086/305925