A VLA-20 AND 90 CENTIMETER RADIO-SURVEY-OF-DISTANT-ABELL CLUSTERS WITH CENTRAL CD GALAXIES

BAGCHI J KAPAHI VK

J. Bagchi et Vk. Kapahi, A VLA-20 AND 90 CENTIMETER RADIO-SURVEY-OF-DISTANT-ABELL CLUSTERS WITH CENTRAL CD GALAXIES, Journal of astrophysics and astronomy, 15(3), 1994, pp. 275-308

61

INGLESE

Article

Astronomy & Astrophysics

Journal of astrophysics and astronomy → ACNP

0250-6335

15

3

1994

275 - 308

ISI

0250-6335(1994)15:3<275:AVA9CR>2.0.ZU;2-V

A radio survey, using the Very Large Array at 20 and 90 cm lambda has been carried out in the direction of 46 distant Abell clusters (0.1 le ss-than-or-similar-to z less-than-or-similar-to 0.3) dominated by a cD galaxy (clusters classified to be Bautz-Morgan I type). A radio sourc e coincident with the cD galaxy was detected in 16 clusters. We find t hat the radio luminosity function of the cD galaxies at 20 cm lambda, and below the luminosity P1.4GHz less-than-or-similar-to 10(24.5) W Hz -1, is similar to that of brightest ellipticals in less clustered envi ronments. Above this luminosity, the cDs seem to have a higher probabi lity of becoming radio sources. The effect of optical brightness on ra dio emission is shown to be the same for the two classes. No significa ntly large population of very-steep-spectrum sources with spectral ind ex alpha > 1.2 (flux density infinity frequency (-alpha)) was found to be associated with cD galaxies. A significant negative correlation is found between the radio luminosity of the cD galaxy and the cooling-t ime of the intra cluster medium near the galaxy. We also present evide nce that the probability of radio emission from first-ranked galaxies is dependent upon their location relative to the geometrical centres o f clusters and thus related to the morphological class and the evoluti onary state of the clusters. We argue that both these effects are prim arily caused by the dynamical evolution of these distant clusters of g alaxies.