HUBBLE-SPACE-TELESCOPE PLANETARY CAMERA OBSERVATIONS OF ARP-220

Planetary Camera images of peculiar galaxy Arp 220 taken with V, R, an d I band filters reveal a very luminous object near the position of th e western radio continuum source, assumed to be the major nucleus, and seven lesser objects within 2'' of this position. The most luminous o bject is formally coincident with the radio source to within the error s of HST pointing accuracy, but we have found an alternate, more compe lling alignment of maps in which the eastern radio source coincides wi th one of the lesser objects and the OH radio sources reside near the surfaces of other optical objects. The proposed centering places the m ost luminous object 150 pc (0.4'') away from the western radio source. We explore the possibilities that the objects are either holes in the dense dust distribution, dusty clouds reflecting a hidden bright nucl eus, or associations of bright young stars. We favor the interpretatio n that at least the brightest two objects are massive young star assoc iations with luminosities 10(9)-10(11)L., but highly extinguished by i ntervening dust. These massive associations should fall into the nucle us on a time scale of 10(8) yr. About 10% of the enigmatic far-IR flux arises from the observed objects. In addition, if the diffuse starlig ht out to a radius of 8'' is dominated by stars with typical ages of o rder 108 yr (the time since the alleged merger of two galaxies), as is indicated by the blue colors at larger radius, then the lower limit t o the reradiation of diffuse starlight contributes 3 x 10(11)L. to the far-infrared flux, or greater-than-or-equal-to 25% of the total far-I R flux. Three additional bright objects (M(V) almost-equal-to -13) loc ated about 6'' from the core are likely young globular clusters, but a ny of these could be recently exploded supernovae instead. The expecte d supernovae rate, if the dominant energy source is young stars, is ab out one per month for the region where the intense far-infrared flux o riginates. Also, individual giant dust clouds are visible in these ima ges. Their typical size is 300 pc (1'').