Clustering of galaxies around radio quasars at 0.5 < z < 0.8

We have observed the galaxy environments around a sample of 21 radio-loud, steep-spectrum quasars at 0.5<z<0.82, spanning several orders of magnitude in radio luminosity. The observations also include background control fields used to obtain the excess number of galaxies in each quasar field. The galaxy excess was quantified using the spatial galaxy-quasar correlation amplitude, B_gq, and an Abell-type measurement, N_0.5 (Hill & Lilly 1991). A few quasars are found in relatively rich clusters, but on average, they seem to prefer galaxy groups or clusters of approximately Abell class 0. We have combined our sample with literature samples extending down to z=0.2 and covering the same range in radio luminosity. By using Spearman statistic to disentangle redshift and luminosity dependences, we detect a weak, but significant, positive correlation between the richness of the quasar environment and the quasar's radio luminosity. However, we do not find any epoch dependence in B_gq, as has previously been reported for radio quasars and galaxies. We discuss the radio luminosity-cluster richness link and possible explanations for the weak correlation that is seen.Comment: 18 pages, 9 figures, submitted to MNRA

The nature of faint radio sources in low frequency samples

SIGLEAvailable from British Library Document Supply Centre- DSC:D59574 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Harvesting World Record wheat crop

A slide showing two pictures of workers of the Noble Foundation harvesting Noble's record-breaking crop

Harvesting World Record wheat crop

A slide showing two pictures of workers of the Noble Foundation harvesting Noble's record-breaking crop

Mrs. Dupont Thompson biography, MSS.0135

Abstract: This collection contains an unpublished biography of Mrs. Dupont Thompson, a board member of Partlow State School in Tuscaloosa, Alabama.Scope and Content Note: This collection contains an unpublished biography of Mrs. Dupont Thompson, a board member of Partlow State School in Tuscaloosa, Alabama.Biographical/Historical Note: Mrs. Dupont Thompson was a board member of Partlow State School in Tuscaloosa, Alabama from 1923 until 1947

Harvesting World Record wheat crop

A slide showing two pictures of workers of the Noble Foundation harvesting Noble's record-breaking crop

Harvesting World Record wheat crop

A slide showing two pictures of workers of the Noble Foundation harvesting Noble's record-breaking crop