Bibcode
Gawroński, M. P.; Peel, M. W.; Lancaster, K.; Battye, R. A.; Birkinshaw, M.; Browne, I. W. A.; Davies, M. L.; Davis, R. J.; Feiler, R.; Franzen, T. M. O.; Génova-Santos, R.; Kus, A. J.; Lowe, S. R.; Pazderska, B. M.; Pazderski, E.; Pooley, G. G.; Roukema, B. F.; Waldram, E. M.; Wilkinson, P. N.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 406, Issue 3, pp. 1853-1864.
Fecha de publicación:
8
2010
Número de citas
14
Número de citas referidas
14
Descripción
Small angular scale (high l) studies of cosmic microwave background
(CMB) anisotropies require accurate knowledge of the statistical
properties of extragalactic sources at cm-mm wavelengths. We have used a
30 GHz dual-beam receiver (One Centimetre Receiver Array prototype) on
the Toruń 32-m telescope to measure the flux densities of 121
sources in Very Small Array fields selected at 15 GHz with the Ryle
Telescope. We have detected 57 sources above a limiting flux density of
5 mJy, of which 31 sources have a flux density greater than 10 mJy,
which is our effective completeness limit. From these measurements we
derive a surface density of sources above 10 mJy at 30 GHz of 2.2 +/-
0.4 deg-2. This is consistent with the surface density
obtained by Mason et al. who observed a large sample of sources selected
at a much lower frequency (1.4 GHz). We have also investigated the
dependence of the spectral index distribution on flux density by
comparing our results with those for sources above 1 Jy selected from
the Wilkinson Microwave Anisotropy Probe 22 GHz catalogue. We conclude
that the proportion of steep spectrum sources increases with decreasing
flux density, qualitatively consistent with the predictions of de Zotti
et al. We find no evidence for an unexpected population of sources above
our completeness limit of 10 mJy whose spectra rise towards high
frequencies, which would affect our ability to interpret current
high-resolution CMB observations at 30 GHz and above.
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