J/ApJ/405/498 J/ApJ/405/498 Counts and spectral indices at 8.44GHz R A Windhorst E B Fomalont R B Partridge J D Lowenthal Astrophys. J. 405 498 1993 1993ApJ...405..498W cosmic microwave background galaxies: evolution galaxies: starburst radio continuum: galaxies surveys We used the VLA to make deep images of two 7x7' fields at 8.44 GHz with 10" resolution. With an rms noise of 3.2 and 5.1 {micro}Jy, respectively, in the two fields, we compiled a catalog of 82 sources. The normalized differential 8.44 GHz counts are similar to those at 1.41 and 4.86 GHz. All show a similarly steep submillijansky slope, which is only somewhat flatter than that expected for a nonevolving Euclidean population ({gamma}=2.5). Microjansky radio sources at 4.86 GHz have been identified with faint blue galaxies (18<~V<~28 mag). We argue that their expected median redshift is about 0.5-0.75. Hence, cosmological evolution may be needed to explain the steep slope of the microjansky counts. The 8.44 GHz counts must converge with slope {gamma}<2.0 below S(8.44)~300 nJy, or they would exceed the available field galaxy counts down to V~28 mag, and they must permanently converge below S(8.44)~20 nJy, or their integrated sky brightness would distort the observed thermal cosmic background radiation spectrum at centimeter wavelengths. The estimated 31.5 GHz sky brightness from nanojansky to jansky levels is <36 {micro}K (3{sigma}). Even if weak radio sources cluster on scales of degrees as faint galaxies do, their anisotropic contribution to the COBE DMR experiment (with 7deg FWHM-beam) would not exceed ~1.2{micro}K.

Name Source name --- n_Name Source with an asterisk is not in the complete sample --- RAh Right ascension (1950) h RAm Right ascension (1950) min RAs Right ascension (1950) s e_RAs One sigma error on right ascension s DEd Declination (1950) deg DEm Declination (1950) arcmin DEs Declination (1950) arcsec e_DEs One sigma error on declination arcsec S8.44 Integrated sky flux density at 8.44GHz uJy e_S8.44 One sigma error on integrated sky flux density uJy l_SizeM When '<' the source is an unresolved source and it's given the 1.5{sigma} upper limit on the Gaussian major axis --- SizeM Deconvolved Gaussian source size (FWHM): major axis arcsec e_SizeM Error on major axis arcsec Sizem Deconvolved Gaussian source size (FWHM): minor axis arcsec e_Sizem Error on minor axis arcsec PA Position angle of major axis deg e_PA Error on position angle deg Weight Source weight in the 8.44 GHz counts --- S(p) Measured peak flux density on the 10arcsec resolution image uJy e_S(p) One sigma error on measured peak flux density uJy S(int) Resulting integrated flux density on the 10 arcsec image uJy e_S(int) One sigma error on resulting integrated flux density uJy James Marcout, Simona Mei CDS 1995May11 UNKNOWN UNKNOWN * March 1993: Number A075 in H. Andernach's list, transformed from original LaTeX provided by the author * Completed at CDS J_ApJ_405_498.xml