On the Origin of Blue Lobes in Central Cooling Flow Galaxies

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Session 55 -- Early Universe
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[55.05] On the Origin of Blue Lobes in Central Cooling Flow Galaxies

D. S. De Young (KPNO/NOAO)

Recent observations of the central galaxy in two rich clusters, A1795 and A2597, each with probable cooling flows, have revealed double lobed distributions of excess blue light. In each case this blue excess is coincident with the emission from a central double radio source. Moreover, in the one case so far observed, the blue continuum appears to be unpolarized and thus unlikely to be due to scattering. Calculations presented here explore the possibility that this blue luminosity is due to young stars produced via jet induced star formation associated with the radio source. Numerical simulation of the jet propagation through the ambient cooling flow ISM, followed by shock induced star formation and subsequent tracking of the stellar orbits in the galaxy and cluster potential allows a study of the development of the blue continuum as a function of space and time. It is found that neither high power nor very low power jets can reproduce the observations. Agreement is obtained best from intermediate power jets which have very short lifetimes of less than 10 million years. These jets match the constraints imposed by blue light morphology, stellar aging, orbital diffusion, and radio luminosity and morphology.

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