J. B. Hutchings

VLA observations of 91 quasars at Z greater than 0.35 and less than 1

We present NRAO-VLA 4 snapshot observations of 91 radio quasars with 0.35 < z < 1 chosen to sample the redshift-luminosity plane as widely as possible, to enable the study of the radio evolution of quasars. Their evolution has been discussed by Hutchings, Price, & Gower and Neff & Hutchings. The observations were made at 6 and 20 cm in the A-array and have ∼ 0.″4 and 1.″2 resolution, respectively. The primary purpose of this paper is to present the radio images and image parameters of a morphologically unbiased and uniformly reduced sample of quasars. We include only a brief discussion of the sample selection, observations, and data reductions. This is the second sample in a series of papers presenting tbe VLA observations of quasars

Radio evolution of quasars at z less than 1

A sample of 128 quasars with redshifts less than 1.0 observed at 6 cm and 20 cm with the A array of the VLA are presented and discussed. It is found that the source size envelope varies with both redshift and core luminosity, being smaller for high values of both. More luminous sources have greater core dominance, and the largest sources tend to have low-luminosity cores. Core variability tends to increase with luminosity and with redshift. The distribution of the ratio of core-lobe distances is consistent with a simple model of initial alternating ejection at nonrelativistic velocities. The ratios of lobe luminosities also show no evidence of relativistic beaming. The evidence suggests a general evolution of individual sources in which the source is initially a luminous core only, whose luminosity falls with time. The lobes develop initially as a one-sided structure, but eventually form large triple sources with a fading core. 21 references.

21 cm emission in QSOs and active galaxies

Observations of H I emission from galaxies containing QSOs and active nuclei, obtained with the Arecibo telescope, are reported, including new data on 17 objects, new detections in four of them, improved profiles in five more, and possible detections in several others. These results are discussed together with published observations of five other objects by the same telescope. This sample lies at higher luminosity and redshift than surveys of Seyfert galaxies. The line profiles are generally broad and asymmetric, probably due to contamination by associated or interacting galaxies. There is a close agreement with optical NLR redshifts, but a mismatch of some 50 km/s is suggested. Overall, the H I masses are lower than for normal galaxies, but they appear to correlate with the nuclear luminosity. This may connect fueling events and ionization by the nuclear radiation. 16 references.

CORRELATED OPTICAL AND RADIO STRUCTURE IN THE QSO 1302-102

We present new optical imaging in two broad-band colors ofthe z=0.29 bright QSO 1302-102, obtained with the Wide Field Camera of the Hubble Space Telescope. We have performed deconvolution on the HST data, previously published CFHT HRCam data, and the combined data. The structure and brightness are measured of an extended knot 2.3 arcsec from the QSO, and also of brighter structure in the inner 1 arcsec of the QSO. We compare the optical structure with new and existing maps of the radio structure from the VLA. The 5 arcsec radio structures lie along the directions of some of the optical components. We discuss the implications.

Evolution of radio quasars for z of less than 2

A sample of 72 radio quasars is used to study the cosmic and individual evolution of quasars in the 1-2 redshift range. It is shown that the most luminous sources at all redshifts are unresolved, and that one-sided and two-sided structures correspond to progressively lower core (and total) luminosities. The sizes and fractional population of triple sources are found to fall steadily with increasing redshift to z of about 1.7. A correlation over many orders of magnitude is noted between the optical and maximum radio-core luminosity. 15 refs.

Radio-continuum emission from quasar host galaxies

Seven low-redshift quasars that are likely to be in spiral galaxies have been observed in a search for radio-continuum emission from the host galaxies of quasars. The properties of the individual quasars are listed, and 1.49 GHz contour maps of the seven quasar fields are presented. Map parameters and radio source parameters are given along with optical images of three of the objects. The results indicate that these quasars probably do reside in spiral galaxies. The radio luminosities, sizes, orientations, and u values all indicate that relativistic beaming alone cannot be used to explain the differences between the present sources and the far stronger radio sources seen in blazars or larger optically selected quasar samples. However, an apparent correlation between the radio luminosity and the ratio of the optical nuclear to host-galaxy luminosity is consistent with some beaming of nuclear radiation. 26 references.

4C 18.68: A QSO with Precessing Radio Jets?

The radio source 4C 18.68, identified with the 16.5 m QSO 2305+187 (z = 0.313), was observed at 20 cm and 6 cm with the VLA in its highest-resolution configuration (A) on April 25, 1981, as part of a programme to map the radio structure of quasars for which optical structure has been mapped using the Canada-France-Hawaii telescope. The radio structure is remarkable, showing complex, curved structure at 6 cm resolution embedded in a halo ~ 60 kpc across (H0 = 100 km/sec/Mpc, q0 = 0) seen most clearly in the 20 cm map.