The K-z relation and radio structure of the TOOT00 and SXDS radio sources

E. Vardoulaki, S. Rawlings, T. Mauch, G. Hill, C. Simpson

Abstract.
We present a near-infrared (K-band) study of two independent radiosource samples, the S ≥ 100 mJy 151-MHz radio-selected TOOT00 (Vardoulaki et al. 2010) and the S ≥ 2 mJy 1.4-GHz radio-selected SXDS (Vardoulaki et al. 2008) radio sources, and compare them to other samples from the literature. Comparison to the K_W-z relation of Willott et al. (2003) suggests that both the TOOT00 and SXDS radio galaxies are brighter than the K_W-z relation defined by 3CRR/6CE/6C^*/7CRS radio galaxies. The median luminosity at K is L_K-Ke-apcor ~ 5 L_K^* for the TOOT00 and ~ 4 L_K^* for the SXDS objects with very few faint outliers, adding to examples identified before. Nearly all TOOT00 objects are simple analogues of bright galaxies in the local (z_med = 0.08) 6dF sample of Mauch & Sadler, apart from sub-L_K^* objects, but in the SXDS, high-z sources probe enough cosmic volume at deep enough K depths to find a population of objects not seen locally. These sub-L_K^* objects at z ~ 1, L_1.4GHz ~ 10²⁴ W Hz^-1 sr^-1, are found in various high-z radio-source samples, like CENSORS and MRCR-SUMSS, but they are rare and might be young dusty galaxies. Finally, the FRI/FRII divide in radio luminosity seen at z << 0.5 is also obeyed at z ~ 1 for FRII objects in the TOOT00 and SXDS samples. Examples of FRI radio sources that are above the FRI/FRII break in radio luminosity are rare but exist in both samples, and can also be seen in the local 6dF sample.

Challenges in Infrared Extragalactic Astrophysics II
Crete, Greece
setembro 2010

Tipo: Poster