The Extremes of AGN Variability

Komossa, S.; Grupe, D.; Schartel, N.; Gallo, Luigi; Gómez, José L.; Kollatschny, W.; Kriss, Gerard A.; Leighly, Karen M.; Longinotti, A. L.; Parker, M. L.; Santos-Lleo, M.; Wilkins, D. R.; Zetzl, M.

doi:10.1017/s1743921317001648

Cited by 26 publications

(32 citation statements)

References 16 publications

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“…Then the X-ray flux of Mrk 335 dropped dramatically in 2007 (Grupe et al 2007(Grupe et al , 2008. Multiple epochs of exceptional flaring and dipping on its way to and beyond this low state motivated several deeper spectroscopic observations with XMM-Newton, Suzaku, NuSTAR, and the HST (Grupe et al 2012;Gallo et al 2013Gallo et al , 2015Gallo et al , 2018Gallo et al , 2019Kara et al 2013;Longinotti et al 2013Longinotti et al , 2019Parker et al 2014;Komossa et al 2017;Choudhury et al 2019;Parker et al 2019). These observations have shown that Mrk 335 is well fit with varying contributions of blurred reflection and (ionized) absorption.…”

Section: Introductionmentioning

confidence: 99%

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

Komossa

Grupe

Gallo

et al. 2020

A&A

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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.

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Section: Introductionmentioning

confidence: 99%

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

Komossa

Grupe

Gallo

et al. 2020

A&A

Self Cite

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“…The main problem with invoking a TDE or supernova near SMBH in some AGN is that they are extremely rare. Repeat tidal stars stripping [17,18] has higher probability [19], but this possibility is not investigated enough yet.…”

Section: Discussionmentioning

confidence: 99%

“…An important way of distinguishing between different possible interpretations of CL NLS1 is trying to determine if these cases are just one-off events. As the case of NGC 2617 discussed above illustrates, recurrent brightening and fading is observed in CL BLS1s [13,19]. It is therefore important to have longterm follow-up monitoring of objects like these CL NLS1 to see if outbursts repeat.…”

Section: Changing-look Nls1s?mentioning

confidence: 99%

Changing-look Narrow-Line Seyfert 1s?

Malanchev¹,

Gaskell²

2018

Proceedings of Revisiting Narrow-Line Seyfert 1 Galaxies and Their Place in the Universe — PoS(NLS1-2018)

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Two major challenges to unification schemes for active galactic nuclei (AGN) are the existence of Narrow-Line Seyfert 1s (NLS1s) and the existence of changing-look (CL) AGNs. AGNs can drastically change their spectral appearance in the optical (changing their Seyfert type) and/or in the X-ray region. We illustrate the CL phenomenon with our multi-wavelength monitoring of NGC 2617 and discuss its properties compared with NLS1s. There are few examples of CL NLS1s and the changes are mostly only in the X-ray region. It has been proposed that some of these could be cases of a tidal-disruption events (TDE) or supernova events. If BLRs have a flat geometry and NLS1s are seen face-on then we have to see CL cases only if the orientation of the BLR changes as a result of a TDE or a close encounter of a star without a TDE. If NLS1s include both high Eddington accretion rate and low-inclination AGNs then a significant fraction of NLS1s could be obscured and would not be identified as NLS1s. CL cases might happen more in such objects if dust sublimation occurs following a strong increase in the optical luminosity.Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe -NLS1 Padova

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“…[3], [25], [43]); (iii) display more extreme spectral variability (e.g. [41], [61], [54]); and (iv) show larger amplitude and more rapid flux variations (e.g. [4], [10], [23], [54]) ( Fig.…”

Section: The X-ray History Of Nls1smentioning

confidence: 99%

X-ray perspective of Narrow-line Seyfert 1 galaxies

Gallo¹

2018

Proceedings of Revisiting Narrow-Line Seyfert 1 Galaxies and Their Place in the Universe — PoS(NLS1-2018)

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It is arguably in the X-ray regime that Narrow-line Seyfert 1 galaxies (NLS1s) exhibit the most extreme behaviour. Spectral complexity, rapid and large amplitude flux variations, and exceptional spectral variability are well known characteristics. However, NLS1s are not eccentric, but form a continuous sequence with typical Seyfert 1 galaxies. Understanding the extreme behaviour displayed by NLS1s will provide insight to the general AGN phenomenon. In this review, I will examine some of the important NLS1 X-ray discoveries over the past twenty years. I will then explore recent work that looks at the nature of the primary X-ray source (i.e. the corona) in NLS1s, demonstrating how the corona can be compact, dynamic, and in some cases consistent with collimated outflow. X-ray observations of NLS1s will be key in determining the nature of the corona, resolving the disc-jet connection, and determining the origin of the radio loud/quiet dichotomy in AGN.

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The Extremes of AGN Variability

Cited by 26 publications

References 16 publications

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

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

Changing-look Narrow-Line Seyfert 1s?

X-ray perspective of Narrow-line Seyfert 1 galaxies

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