On the multi-wavelength variability of Mrk 110: Two components acting at different timescales

TL;DR

This study uses intensive multi-wavelength monitoring to analyze the variability of Mrk 110, revealing two distinct timescale-dependent behaviors in its continuum reverberation, indicating complex emission processes.

Contribution

First detailed multi-wavelength reverberation mapping of Mrk 110, identifying two different variability components at short and long timescales.

Findings

Short timescale lags increase with wavelength, consistent with disc reverberation.

Long timescale lags suggest interplay between disc emission and broad line region radiation.

Mrk 110 shows significant variability across all observed wavebands.

Abstract

We present the first intensive continuum reverberation mapping study of the high accretion rate Seyfert galaxy Mrk 110. The source was monitored almost daily for more than 200 days with the Swift X-ray and UV/optical telescopes, supported by ground-based observations from Las Cumbres Observatory, the Liverpool Telescope, and the Zowada Observatory, thus extending the wavelength coverage to 9100 \r{A}. Mrk 110 was found to be significantly variable at all wavebands. Analysis of the intraband lags reveals two different behaviours, depending on the timescale. On timescales shorter than 10 days the lags, relative to the shortest UV waveband ($\sim1928$ \r{A}), increase with increasing wavelength up to a maximum of $\sim2$days lag for the longest waveband ($\sim9100$ \r{A}), consistent with the expectation from disc reverberation. On longer timescales, however, the g-band lags the Swift BAT hard X-rays by $\sim10$ days, with the z-band lagging the g-band by a similar amount, which cannot be explained in terms of simple reprocessing from the accretion disc. We interpret this result as an interplay between the emission from the accretion disc and diffuse continuum radiation from the broad line region.