  A common feature of the X-ray bubbles observed in Chandra images of some
"cooling flow" clusters is that they appear to be surrounded by bright, cool
shells. Temperature maps of a few nearby luminous clusters reveal that the
shells consist of the coolest gas in the clusters -- much cooler than the
surrounding medium. Using simple models, we study the effects of this cool
emission on the inferred cooling flow properties of clusters. We find that the
introduction of bubbles into model clusters that do NOT have cooling flows
results in temperature and surface brightness profiles that resemble those seen
in nearby "cooling flow" clusters. They also approximately reproduce the recent
XMM-Newton and Chandra observations of a high minimum temperature of 1-3 keV.
Hence, bubbles, if present, must be taken into account when inferring the
physical properties of the ICM. In the case of some clusters, bubbles may
account entirely for these observed features, calling into question their
designation as clusters with cooling flows. However, since not all nearby
"cooling flow" clusters show bubble-like features, we suggest that there may be
a diverse range of physical phenomena that give rise to the same observed
features.
