J/ApJ/405/498 Counts and spectral indices at 8.44GHz (Windhorst+, 1993)
Microjansky source counts and spectral indices at 8.44 GHz
WINDHORST R.A., FOMALONT E.B., PARTRIDGE R.B., LOWENTHAL J.D.
<Astrophys. J. 405, 498 (1993)>
=1993ApJ...405..498W 1993ApJ...405..498W (SIMBAD/NED Reference)
ADC_Keywords: Regional catalog; Radio sources
Keywords: cosmic microwave background - galaxies: evolution -
galaxies: starburst - radio continuum: galaxies - surveys
Description:
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 (γ=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 γ<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 (3σ). 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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1a 111 47 Catalog of 8.44 GHz Radio Sources in
the Linx.2 Field
table1b 111 36 Catalog of 8.44 GHz Radio Sources in
the Cepheus Field
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Byte-by-byte Description of file: table1a table1b
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Source name
7 A1 --- n_Name [*] Source with an asterisk is not
in the complete sample
10 I1 h RAh Right ascension (1950)
12- 13 I2 min RAm Right ascension (1950)
15- 19 F5.2 s RAs Right ascension (1950)
21- 24 F4.2 s e_RAs One sigma error on right ascension
26- 27 I2 deg DEd Declination (1950)
29- 30 I2 arcmin DEm Declination (1950)
32- 35 F4.1 arcsec DEs Declination (1950)
38- 40 F3.1 arcsec e_DEs One sigma error on declination
42- 48 F7.1 uJy S8.44 Integrated sky flux density at 8.44GHz
49- 55 F7.1 uJy e_S8.44 One sigma error on integrated sky flux
density
57 A1 --- l_SizeM [<] When '<' the source is an unresolved
source and it's given the 1.5σ upper
limit on the Gaussian major axis
58- 61 F4.1 arcsec SizeM Deconvolved Gaussian source size (FWHM):
major axis
63- 65 F3.1 arcsec e_SizeM []? Error on major axis
67- 70 F4.1 arcsec Sizem []? Deconvolved Gaussian source size
(FWHM): minor axis
72- 74 F3.1 arcsec e_Sizem []? Error on minor axis
76- 78 I3 deg PA []? Position angle of major axis
80- 81 I2 deg e_PA []? Error on position angle
83- 86 F4.2 --- Weight Source weight in the 8.44 GHz counts
88- 93 F6.2 uJy S(p) Measured peak flux density on the
10arcsec resolution image
95- 98 F4.2 uJy e_S(p) One sigma error on measured peak
flux density
100-105 F6.2 uJy S(int) Resulting integrated flux density
on the 10 arcsec image
107-111 F5.2 uJy e_S(int) One sigma error on resulting integrated
flux density
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Historical Notes:
* March 1993: Number A075 in H. Andernach's list, transformed
from original LaTeX provided by the author
* Completed at CDS
(End) James Marcout, Simona Mei [CDS] 11-May-1995