Optical Variability of the Radio Source J 1128+5925 -- II. Confirmation of its Optical Quietness

TL;DR

This study confirms that the radio source J 1128+5925 remains optically quiet over multiple timescales, supporting the idea that its radio variability is caused by interstellar scintillation rather than intrinsic changes.

Contribution

The paper provides new optical monitoring data from 2008 that confirms the source's optical quietness and distinguishes its radio variability origin from optical behavior.

Findings

No optical variability detected over hours to months

Optical quietness persists over one year

Radio variability likely caused by interstellar scintillation

Abstract

The source J 1128+5925 was found recently to show strong intraday variability at radio wavelengths and its radio variability may come from interstellar scintillation. In optical, the object was quiet in our 2007 monitoring session. Here we report the results of our new optical monitoring of this source in 2008. In addition to confirm our 2007 results, that the object did not display any clear variation on timescales from hour--day to month, we provide evidence that the object does not vary on timescale of one year, and it is probably intrinsically quiet in optical domain. Its very different behaviors in optical and radio regimes can be naturally explained if its strong radio variability comes from interstellar scintillation.