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Description
The authors used the 1.4-GHz NRAO VLA Sky Survey (NVSS) to study radio sources in two color-selected QSO samples: a volume-limited sample of 1,313 QSOs defined by M<sub>i</sub> < -23 in the redshift range 0.2 < z < 0.45 and a magnitude-limited sample of 2,471 QSOs with m<sub>r</sub> <= 18.5 and 1.8 < z < 2.5. About 10% were detected above the 2.4-mJy NVSS catalog limit and are powered primarily by active galactic nuclei (AGNs). The space density, rho, of the low-redshift QSOs evolves as rho ~ (1 + z)<sup>6</sup>. In both redshift ranges, the flux-density distributions and luminosity functions of QSOs stronger than 2.4 mJy are power laws, with no features to suggest more than one kind of radio source. Extrapolating the power laws to lower luminosities predicts the remaining QSOs should be extremely radio quiet, but they are not. Most were detected statistically on the NVSS images with median peak flux densities S<sub>p</sub> of ~ 0.3 mJy/beam and ~ 0.05 mJy/beam in the low- and high-redshift samples, corresponding to spectral luminosities log L<sub>1.4GHz</sub> ~ 22.7 and ~ 24.1 W/Hz, respectively. The authors suggest that the faint radio sources are powered by star formation at rates dM/dt of ~ 20 M_{sun}_/yr in the moderate luminosity (median M<sub>i</sub> of ~ -23.4) low-redshift QSOs and dM/dt ~ 500M<sub>sun</sub>/yr in the very luminous (median M<sub>i</sub> ~ -27.5) high-redshift QSOs. Such luminous starbursts (<log(L<sub>IR</sub>/L<sub>sun</sub>)> ~ 11.2 and ~ 12.6, respectively) are consistent with "quasar mode" accretion in which cold gas flows fuel both AGN and starburst. The SDSS DR7 QSO catalog (Schneider et al. 2010, AJ, 139, 2360) is complete to i = 19.1 mag over a solid angle of 2.66 sr around the North Galactic Pole. It contains the small sample of 179 color-selected QSOs defined by M<sub>i</sub> < -23 in the narrow redshift range 0.2 < z < 0.3 studied by Kimball et al. (2011, ApJ, 739, L29) and the larger sample of 1,313 QSOs in the wider redshift range 0.2 < z < 0.45 discussed here. Note that these magnitudes were calculated for an H<sub>0</sub>= 71 km/s/Mpc and Omega<sub>M</sub> = 0.27 modern flat LambdaCDM cosmology. The entire SDSS DR7 area is covered by the NVSS, whose source catalog is complete for statistical purposes above a peak flux density S<sub>p</sub> ~ 2.4 mJy/beam at 1.4 GHz. In the redshift range 0.2 < z < 0.45 the 45" FWHM (full width between half-maximum points) beam of the NVSS spans 150 - 250 kpc. There are 163 (12%) NVSS detections of the 1,313 QSOs in the redshift range 0.2 < z < 0.45 which are listed in Table 1 of the reference paper. The authors also chose a magnitude-limited sample of all 2,471 color-selected DR7 QSOs brighter than m<sub>r</sub> = 18.5 in the redshift range 1.8 < z < 2.5. The NVSS detected radio emission stronger than S = 2.4 mJy from only 191 (8%) of them: these are listed in Table 3 of the reference paper. This HEASARC table contains the contents of both samples described above. It thus has 163 + 191 = 354 entries, the sum of Tables 1 and 3 from the reference paper. To select only the entries from Table 1, the user should select entries with redshifts from 0.2 to 0.45. To select only the entries from Table 3, the user should select entries with redshifts > 1.8. This table was created by the HEASARC in January 2015 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/768/37">CDS Catalog J/ApJ/768/37</a> files table1.dat and table3.dat. This is a service provided by NASA HEASARC .
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