Galaxy formation and evolution

Abstract:

We use three samples (3CRR, 6CE and 6C*) to investigate the radio luminosity function (RLF) for the 'most powerful' low-frequency selected radio sources. We find that the data are well fitted by a model with a constant ca-moving space density at high redshift as well as by one with a declining co-moving space density above some particular redshift. This behaviour is very similar to that inferred for steep-spectrum radio quasars by Willott et al (1998) in Line with the expectations of Unified Schemes. We conclude that there is as yet no evidence for a 'redshift cutoff' in the co-moving space densities of powerful classical double radio sources, and rule out a art-off at z less than or similar to 2.5.

Abstract:

Near infrared instrumentation at 4 and 8 meter class telescopes has grown rapidly in the past few years with the advent of 1024(2) and 2048(2) detector arrays. We present a brief review of high resolution spectroscopic capabilities available worldwide, with an eye on new developments, e.g. spatially resolved spectroscopy offered by integral field instruments.Observing at near-infrared wavelengths has its own quirks. We discuss observing strategies to get past the limits of high background (including both thermal background and background due to OH sky emission lines), Variations in atmospheric transmission, and detector constraints. Special attention is given to the subject of OH suppression/avoidance, which can significantly increase the sensitivity in the J, EI and short K windows. This is especially important for (fainter) high redshift targets, where the rest frame visible diagnostic lines are shifted into the near infrared.