SIMBAD references

2002AJ....123..637D - Astron. J., 123, 637-677 (2002/February-0)

Optical and near-infrared imaging of ultra-steep-spectrum radio sources: the K-z diagram of radio-selected and optically selected galaxies.


Abstract (from CDS):

We present optical and/or near-IR images of 128 ultra-steep-spectrum radio sources. Roughly half of the objects are identified in the optical images (R≲24), while in the near-IR images, more than 94% are detected at K≲22. The mean K magnitude is K{d1}=19.26 within a 2" diameter aperture. The distribution of R-K colors indicates that at least one-third of the objects observed have very red colors (R-K>5). The major axes of the identifications in the K band are preferentially oriented along the radio axes, with half of them having compact morphologies. The 22 sources with spectroscopic redshifts and K-band magnitudes follow the K-z relation found from previous radio samples, but with a larger scatter. We argue that this may be due to a dependence of K magnitude on the radio power, with the most luminous radio sources inhabiting the most massive host galaxies. We present a composite K-z diagram of radio-loud and radio-quiet galaxies, selected from the Hubble Deep Field (North) and the Hawaii surveys. Out to z≲1, the radio-loud galaxies trace the bright envelope of the radio quiet galaxies, while at z≳1, the radio-loud galaxies are ≳2 mag brighter. We argue that this is not due to a contribution from the active galactic nucleus or emission lines. This difference strongly suggests that radio galaxies pinpoint the most massive systems out to the highest known redshifts, probably as a result of the mutual correlation of the mass of the galaxy and the radio power on the mass of the central black hole.

Abstract Copyright:

Journal keyword(s): Galaxies: Active - Galaxies: Formation - Galaxies: Photometry - Galaxies: Structure - Stars: Pulsars: General - Radio Continuum - Surveys

VizieR on-line data: <Available at CDS (J/AJ/123/637): table5.dat table6.dat table7.dat>

Nomenclature: Table 6, Fig.12: [DVS2002] WN JHHMM+DDMM A(IR), [DVS2002] WN JHHMM+DDMM A(opt), [DVS2002] TN JHHMM+DDMM A(IR), [DVS2002] TN JHHMM+DDMM A(opt), [DVS2002] MP JHHMM+DDMM A(IR), N=129.

CDS comments: In table 5, WN J0837-1053 is a misprint for TN J0837-1053; in table 6, TN J0859-1510 is a misprint for TN J0856-1510.

Simbad objects: 266

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