A shrinking Compact Symmetric Object: J11584+2450?

TL;DR

This paper reports multi-epoch VLBA observations of J11584+2450, revealing it as a compact symmetric object with hot spots retreating towards the core, challenging existing models of CSO evolution.

Contribution

It provides the first evidence of hot spot retreat in a CSO, suggesting possible physical contraction and implications for CSO evolution models.

Findings

Hot spots are retreating at ~0.3c.

J11584+2450 is confirmed as a CSO.

Potential physical contraction observed.

Abstract

We present multi-frequency multi-epoch 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 9 years shows the edge brightened hot spots retreating towards 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.