A recently reported 'bump' in the cosmic microwave background - When could it have originated?

A preliminary discussion of possible mechanisms which could be the cause of the large-scale signal (about 6 deg) in the cosmic microwave background (CMB) recently reported by the Tenerife group is presented. The angular scale of this signal is of particular interest. In fact, the required large-scale coherence greatly restricts the range of possible explanations. Possible scenarios for a primordial origin, as well as that involving a nearby, localized extragalactic source are examined. In the latter case, theoretical signals have been processed to show the dependence of the final received signal on smoothing from the experimental beam, on double subtraction, and on scan trajectory. 52 refs