Lifting the curtain: The Seyfert galaxy Mrk 335 emerges from deep low-state in a sequence of rapid flare events

Abstract

Context. The narrow-line Seyfert 1 galaxy Mrk 335 was one of the X-ray brightest active galactic nuclei, but it has systematically faded since 2007. Aims. We report the discovery with Swift of a sequence of bright and rapid X-ray flare events that reveal the emergence of Mrk 335 from its ultra-deep multiyear low state. Methods. Results are based on our dedicated multiyear monitoring of Mrk 335 with Swift. Results. Unlike other bright active galactic nuclei, the optical–UV is generally not correlated with the X-rays in Mrk 335 on a timescale of days to months. This fact either implies the absence of a direct link between the two emission components; or else implies that the observed X-rays are significantly affected by (dust-free) absorption along our line of sight. The UV and optical, however, are closely correlated at the 99.99% confidence level. The UV is leading the optical by Δt = 1.5 ± 1.5 d. The Swift X-ray spectrum shows strong deviations from a single power law in all brightness states of the outbursts, indicating that significant absorption or reprocessing is taking place. Mrk 335 displays a softer-when-brighter variability pattern at intermediate X-ray count rates, which has been seen in our Swift data since 2007 (based on a total of 590 observations). This pattern breaks down at the highest and lowest count rates. Conclusions. We interpret the 2020 brightening of Mrk 335 as a decrease in column density and covering factor of a partial-covering absorber along our line of sight in the form of a clumpy accretion-disk wind that reveals an increasing portion of the intrinsic emission of Mrk 335 from the disk and/or corona region, while the optical emission-line regions receive a less variable spectral energy distribution. This then also explains why Mrk 335 was never seen to change its optical Seyfert type (not “changing look”) despite its factor ∼50 X-ray variability with Swift.

What controls the UV-to-X-ray continuum shape in quasars?

“…The consistency of this result with those in the literature further 12 We highlight the low-luminosity PG quasar Mrk 335 in Figures 2-4 because it has displayed extreme X-ray variability on short timescales (e.g. Komossa et al 2020), and thus the measurement of 𝛼 ox , He EW, and 𝐿 2500 might be highly variable. This one quasar, however, does not affect greatly the fitted relationships.…”

“…sample was constructed using quasars from multiple different samples that often had large temporal gaps between the observations. Despite the differences in the epoch of observation (generally > 1 year), only the low-luminosity quasar Mrk 335 was identified to have extreme X-ray variability (Komossa et al 2020). The extreme X-ray variability of Mrk 335 causes this object to be an extreme outlier with respect to the rest of the data, particularly in Figures 3 and 4.…”

Detection of a Parsec-Scale Jet in a Radio-Quiet Narrow-Line Seyfert 1 Galaxy with Highly Accreting Supermassive Black Hole

“…Gallo et al 2018;Tripathi et al 2020). However, since the coronal optical emission lines, which are supposed to be driven by EUV and soft X-rays, do not vary much in Mrk 335 (Grupe et al 2008), it was suggested that such huge X-ray variability is due to the variable column density and covering factor of the X-ray absorbers near the SMBH (Komossa et al 2020). Therefore, even considering the above uncertainties of 𝐿 bol , the Eddington ratio of Mrk 335 is still high.…”

“…doublepeaked emission lines, systematic line shifts, periodic behaviour or dual bright compact radio cores, for the existence of binary black hole system in Mrk 335. Another possible mechanism causing the S-shaped jet would be the warped disk near the jet launching site, arising from non-axisymmetric radiation (Pringle 1996) or accretion events, the latter of which would be interesting given that Mrk 335 is accreting at such high Eddington ratio and has been detected for several flares in optical and X-rays during the past decades (Komossa et al 2020). However, the current data set is not adequate to confirm the validity of they S-shaped jet structure in Mrk 335.…”

“…Peterson et al 2004;Grier et al 2012;Du et al 2014) and X-rays (e.g. Grupe et al 2008;Gallo et al 2018Gallo et al , 2019Tripathi et al 2020;Komossa et al 2020). Based on its optical luminosity and hard X-ray spectrum, Mrk 335 was suggested to host a candidate of super-Eddington accreting massive black hole (Wang et al 2013(Wang et al , 2014.…”