A Sample of Ultra Steep Spectrum Sources Selected from the Westerbork In the Southern Hemisphere (WISH) survey
نویسندگان
چکیده
The 352 MHz Westerbork In the Southern Hemisphere (WISH) survey is the southern extension of the WENSS, covering 1.60 sr between −9 < δ < −26 to a limiting flux density of ∼18 mJy (5σ). Due to the very low elevation of the observations, the survey has a much lower resolution in declination than in right ascension (54 × 54cosecδ). A correlation with the 1.4 GHz NVSS shows that the positional accuracy is less constrained in declination than in right ascension, but there is no significant systematic error. We present a source list containing 73570 sources. We correlate this WISH catalogue with the NVSS to construct a sample of faint Ultra Steep Spectrum (USS) sources, which is accessible for follow-up studies with large optical telescopes in the southern hemisphere. This sample is aimed at increasing the number of known high redshift radio galaxies to allow detailed follow-up studies of these massive galaxies and their environments in the early Universe.
منابع مشابه
A new search for distant radio galaxies in the southern hemisphere – I. Sample definition and radio properties
This paper introduces a new program to find high-redshift radio galaxies in the southern hemisphere through ultra-steep spectrum (USS) selection. We define a sample of 234 USS radio sources with spectral indices α 408 ≤ −1.0 (Sν ∝ ν α) and flux densities S408 ≥ 200 mJy in a region of 0.35 sr, chosen by cross-correlating the revised 408 MHz Molonglo Reference Catalogue, the 843 MHz Sydney Univer...
متن کاملA new search for distant radio galaxies in the Southern hemisphere – III . Optical spectroscopy and analysis of the MRCR – SUMSS sample ⋆
We have compiled a sample of 234 ultra-steep-spectrum(USS)-selected radio sources in order to find high-redshift radio galaxies (HzRGs). The sample is in the southern sky at −40 < δ < −30 which is the overlap region of the 408-MHz Revised Molonglo Reference Catalogue, 843-MHz Sydney University Molonglo Sky Survey (the MRCR–SUMSS sample) and the 1400-MHz NRAO VLA Sky Survey. This is the third in...
متن کاملA sample of southern Compact Steep Spectrum radio sources : The VLBI observations ⋆
A small sample of 7 southern Compact Steep Spectrum (CSS) radio sources has been selected as part of the study of a larger flux-limited complete sample of radio sources. High resolution images, using the VLBI network in the southern hemisphere and the high resolution MERLIN array, are presented for all sources in the CSS sample. The overall morphology of each source consists of well-defined dou...
متن کاملNear-infrared K−band imaging of a sample of Ultra-Steep-Spectrum radio sources selected at 74 MHz
In this paper we present near-infrared K−band imaging of a sample of ultra-steep spectrum (USS) radio sources selected at 74 MHz. The dual selection criteria of low frequency and USS means that we should be sensitive to the highest redshift (z > 5) radio galaxies. We have obtained K−band magnitudes for all of the objects in our sample of 26 and discuss the properties of each. There is a pronoun...
متن کاملA Sample of 669 Ultra Steep Spectrum Radio Sources to Find High Redshift Radio Galaxies ⋆
Since radio sources with Ultra Steep Spectra (USS; α ∼ < −1.30;S ∝ ν) are efficient tracers of high redshift radio galaxies (HzRGs), we have defined three samples of such USS sources using the recently completed WENSS, TEXAS, MRC, NVSS and PMN radiosurveys. Our combined sample contains 669 sources with S1400 > 10 mJy and covers virtually the entire sky outside the Galactic plane (|b| > 15). For...
متن کامل