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Induced star formation and morphological evolution in very high redshift radio galaxies

Wil van Breugel·A. Stanford·A. Dey·G. Miley·D. Stern·H. Spinrad·J. Graham·P. McCarthy
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Abstract

Near-infrared, sub-arcsecond seeing images obtained with the W. M. Keck I Telescope of show strong evolution at rest--frame optical} wavelengths in the morphologies of high redshift radio galaxies (HzRGs) with 1.9 3, to much more compact and symmetrical shapes at z<3. The linear sizes (~10 kpc) and luminosities (M_B~-20 to -22) of the individual components in the z>3 HzRGs are similar to the total sizes and luminosities of normal, radio--quiet, star forming galaxies seen at z=3--4. `R'-band, 0.1 arcsec resolution images with the Hubble Space Telescope of one of these HzRGs, 4C41.17 at z=3.800, show that at rest--frame UV wavelengths the galaxy morphology breaks up in even smaller, ~1 kpc--sized components embedded in a large halo of low surface brightness emission. The brightest UV emission is from a radio--aligned, edge-brightened feature (4C41.17-North) downstream from a bright radio knot. A narrow--band Lyman-alpha image, also obtained with HST, shows an arc--shaped Lyman-alpha feature at this same location, suggestive of a strong jet/cloud collision. Deep spectropolarimetric observations with the W. M. Keck II Telescope of 4C41.17 show that the radio--aligned UV continuum is unpolarized. (abridged)

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Wil van Breugel, A. Stanford, A. Dey, G. Miley, D. Stern, H. Spinrad, J. Graham, P. McCarthy. 1998-09-15. Induced star formation and morphological evolution in very high redshift radio galaxies. https://arxiv.org/abs/astro-ph/9809186

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