A Deep, High-Resolution Survey at 74 MHz

Abstract

We present a 74 MHz survey of a 165 square degree region located near the north galactic pole. This survey has an unprecedented combination of both resolution (25'' FWHM) and sensitivity (RMS noise as low as 24 mJy/beam). We detect 949 sources at the 5-sigma level in this region, enough to begin exploring the nature of the 74 MHz source population. We present differential source counts, spectral index measurements and the size distribution as determined from counterparts in the high resolution FIRST 1.4 GHz survey. We find a trend of steeper spectral indices for the brighter sources. Further, there is a clear correlation between spectral index and median source size, with the flat spectrum sources being much smaller on average. Ultra-steep spectrum objects (alpha < -1.2) are identified, and we present high resolution VLA follow-up observations of these sources which, identified at such a low frequency, are excellent candidates for high redshift radio galaxies.

31 pages, 11 figures, accepted for publication in ApJS

References in corpus (19)

• The Demography of Massive Dark Objects in Galaxy Centres
• Lyman Break Galaxies at z>4 and the Evolution of the UV Luminosity Density at High Redshift
• Spectroscopic Confirmation of a Population of Normal Star-Forming Galaxies at Redshifts z>3
• Quasars, their host galaxies, and their central black holes
• The Nature and Evolution of Classical Double Radio Sources from Complete Samples
• A Redshift z = 6.56 Galaxy Behind the Cluster Abell 370
• Near-infrared imaging and the K-z relation for radio galaxies in the 7C Redshift Survey
• A submillimetre survey of the star-formation history of radio galaxies
• A Sample of 669 Ultra Steep Spectrum Radio Sources to Find High Redshift Radio Galaxies
• The Discovery of Two Lyman$\alpha$ Emitters Beyond Redshift 6 in the Subaru Deep Field
• Radio Continuum Imaging of High Redshift Radio Galaxies
• A Radio Galaxy at z=5.19
• Optical and Near-IR Imaging of Ultra Steep Spectrum Radio Sources - The K-z diagram of radio and optically selected galaxies
• A sample of 6C radio sources designed to find objects at redshift > 4: III --- imaging and the radio galaxy K-z relation
• The black hole mass of low redshift radiogalaxies
• A sample of 6C radio sources designed to find objects at redshift > 4: the radio data
• The Radio Luminosity Function of Cluster Radio Halos
• Discovery of a z = 6.17 galaxy from CFHT and VLT observations
• SCUBA Observations of High Redshift Radio Galaxies

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