The curtain remains open: NGC 2617 continues in a high state

Oknyansky, V. L.; Gaskell, C. M.; Huseynov, N.; Lipunov, V.; Shatsky, N. I.; Tsygankov, Sergey S.; Gorbovskoy, E.; Mikailov, Kh. M.; Татарников, А. М.; Buckley, D.; Metlov, V. G.; Nadzhip, A. E.; Kuznetsov, A.; Balanutza, P.V.; Бурлак, М. А.; Галазутдинов, Г. А.; Артамонов, Б. П.; Salmanov, I. R.; Malanchev, Konstantin; Oknyansky, R S

doi:10.1093/mnras/stx149

Cited by 51 publications

(72 citation statements)

References 30 publications

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“…Many AGN display significant changes in their broad-line shapes, including CL AGN, for example, NGC 5548 (Bon et al 2016) or NGC 2617 (Oknyansky et al 2017). In the case of Mrk 1018, the blue wing asymmetry in the broad-line shape during the global dimming phase (McElroy et al 2016) faded away after 2015, whereas a prominent red wing asymmetry appeared less than four weeks before the brief outburst.…”

Section: Discussion and Summarymentioning

confidence: 99%

The Close AGN Reference Survey (CARS)

Krumpe

Tremblay

Urrutia

et al. 2017

A&A

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After changing optical AGN type from 1.9 to 1 in 1984, the AGN Mrk 1018 recently reverted back to its type 1.9 state. Our ongoing monitoring now reveals that the AGN has halted its dramatic dimming, reaching a minimum around October 2016. The minimum was followed by an outburst rising with ∼0.25 U-band mag/month. The rebrightening lasted at least until February 2017, as confirmed by joint Chandra and Hubble observations. Monitoring was resumed in July 2017 after the source emerged from sunblock, at which point the AGN was found only ∼0.4 mag brighter than its minimum. The intermittent outburst was accompanied by the appearance of a red wing asymmetry in broad-line shape, indicative of an inhomogeneous broad-line region. The current flickering brightness of Mrk 1018 following its rapid fading either suggests that the source has reignited, remains variable at a low level, or may continue dimming over the next few years. Distinguishing between these possibilities requires continuous multiwavelength monitoring.

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Section: Discussion and Summarymentioning

confidence: 99%

The Close AGN Reference Survey (CARS)

Krumpe

Tremblay

Urrutia

et al. 2017

A&A

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“…However, observational evidence strongly favors a compact corona (Mosquera et al 2013;Reis & Miller 2013), which makes some aspects of the reprocessing model very likely, and continuing multi-wavelength monitoring of this and other Seyfert 1s is therefore an important avenue for further investigations. For example, see Giustini et al (2017) for an analysis of the X-ray emission in NGC 2617 during 2013, and Oknyansky et al (2017) for an analysis of the X-ray through IR emission in 2016. Figure 5 shows the lags as a function of wavelength for each object.…”

Section: Challenges To the Disk Reprocessing Modelmentioning

confidence: 99%

Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies

Fausnaugh

Starkey

Horne

et al. 2018

ApJ

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We present optical continuum lags for two Seyfert 1 galaxies, MCG+08-11-011 and NGC 2617, using monitoring data from a reverberation mapping campaign carried out in 2014. Our light curves span the ugriz filters over four months, with median cadences of 1.0 and 0.6 days for MCG+08-11-011 and NGC 2617, respectively, combined with roughly daily X-ray and near-UV data from Swift for NGC 2617. We find lags consistent with geometrically thin accretion-disk models that predict a lag-wavelength relation of τ ∝ λ 4/3. However, the observed lags are larger than predictions based on standard thin-disk theory by factors of 3.3 for MCG+08-11-011 and 2.3 for NGC 2617. These differences can be explained if the mass accretion rates are larger than inferred from the optical luminosity by a factor of 4.3 in MCG+08-11-011 and a factor of 1.3 in NGC 2617, although uncertainty in the SMBH masses determines the significance of this result. While the X-ray variability in NGC 2617 precedes the UV/optical variability, the long (2.6 day) lag is problematic for coronal reprocessing models.

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“…We must stress that, contrary to what is sometimes thought, the CL phenomenon is not rare among the BLS1s and QSOs. A large fraction of strongly-variable AGNs will probably show type changes if observed enough [8]. We note that there are similarities in X-ray variability of CL AGNs and NLS1s.…”

Section: Discussionmentioning

confidence: 63%

“…[20]). As it has been shown [11,8,21] variability of NGC 2617 at all wavelengths is well correlated and the lags relative to X-ray variability increase with wavelength. Typically, the UV lags the X-rays by about 1.5-3 days but optical variations lag the UV by only ≈ 0.5 days.…”

Section: Monitoring Of the Typical CL Object Ngc 2617mentioning

confidence: 62%

“…CL AGNs cases can be explained with either changing obscuration and a change in accretion rates. We have suggested [8] that there can be a combination of these two factors: i.e., that a change in the energy-generation rate leads to a change in absorption of energy by dust. In our proposed hollow bi-conical dust distribution model [9] (see Fig.1), sublimation or recreation of dust in some cloud along our line of sight in the hollow cone can explain the changing look of an AGN.…”

Section: Introductionmentioning

confidence: 99%

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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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The curtain remains open: NGC 2617 continues in a high state

Cited by 51 publications

References 30 publications

The Close AGN Reference Survey (CARS)

The Close AGN Reference Survey (CARS)

Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies

Changing-look Narrow-Line Seyfert 1s?

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