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1999A&A...342..378G - Astronomy and Astrophysics, volume 342, 378-388 (1999/2-2)

The "angular size - redshift" relation for compact radio structures in quasars and radio galaxies.

GURVITS L.I., KELLERMANN K.I. and FREY S.

Abstract (from CDS):

We discuss the angular size - redshift'' relation for compact radio sources distributed over a wide range of redshifts 0.011≤z≤4.72. Our study is based on a sample of 330 5 GHz VLBI contour maps taken from the literature. Unlike extended source samples, the angular size - redshift'' relation for compact radio sources appears consistent with the predictions of standard Friedmann world models with q0≃0.5 without the need to consider evolutionary or selection effects due to a linear size - luminosity'' dependence. By confining our analysis to sources having a spectral index, -0.38≤α≤0.18, and a total radio luminosity, Lh2≥1026W/Hz (H0=100hkm/s/Mpc, q0=0.5 used as a numerical example), we are able to restrict the dispersion in the angular size - redshift'' relation. The best fitting regression analysis in the framework of the Friedmann-Robertson-Walker model gives the value of the deceleration parameter q0=0.21±0.30 if there are no evolutionary or selection effects due to a linear size - luminosity'', linear size - redshift'' or linear size - spectral index'' dependence.

Journal keyword(s): galaxies: active - galaxies: quasars: general - cosmology: observations - radio continuum: galaxies

VizieR on-line data: <Available at CDS (J/A+A/342/378): refs.dat table1.dat table1.ps table1.tex>

CDS comments: Table 1 : objets with references HB97 or HB95 are CJ2 HHMM+DDd.