A shrinking compact symmetric object: J11584+2450?

Abstract

We present multifrequency, multiepoch, Very Long Baseline Array (VLBA) observations of J11584+2450. These observations clearly show this source, previously classified as a core jet, to be a compact symmetric object (CSO). Comparisons between these new data and data taken over the last 11 years shows the edge-brightened hot spots retreating toward the core (and slightly to the west) at approximately 0.3c. Whether this motion is strictly apparent or actually physical in nature is discussed, as well as possible explanations, and what implications a physical contraction of J11584+2450 would have for current CSO models.