Short-term emission line and continuum variations in Mrk 110

Kollatschny, W.; Bischoff, K.; Robinson, E. L.; Welsh, William F.; Hill, Gary J.

doi:10.1051/0004-6361:20011323

Cited by 54 publications

(88 citation statements)

References 23 publications

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“…Spectral observations on a daily basis are needed to solve this question that the He ii λ4686 line originates in the innermost region while the Hα line originates in more exterior regions than Hβ as has been found e.g. in Mrk 110 (Kollatschny et al 2001) We compare our observed velocity-delay pattern with model calculations of Welsh & Horne (1991), Perez et al (1992), O'Brien et al (1994), Horne et al (2004), and with results of Mrk 110 (Kollatschny 2003).…”

Section: D Velocity Mapmentioning

confidence: 76%

“…It is known from other galaxies (e.g. Mrk 110, Kollatschny et al 2001) that the He ii λ4686 line exhibits shorter delays with respect to the ionizing continuum than the Hβ line. The apparent negative delay of two light-days with respect to the continuum light curve at 5180 Å might be caused by a general systematic error or by an alternative possibility that the continuum flux at 5180 Å does not correspond to the ionizing continuum flux.…”

Section: -D Ccf Of the Hα And Hβ Line Profilesmentioning

confidence: 95%

“…The line widths of Mrk 926 amount to 10 000 km s −1 (FWHM) compared to line widths of 2000 km s −1 only in Mrk 110 (Kollatschny et al 2001). It has been demonstrated that the narrow Balmer and helium emission lines in Mrk 110 originate in an accretion disk seen nearly face on (Kollatschny 2002(Kollatschny , 2003.…”

Section: D Velocity Mapmentioning

confidence: 97%

“…Therefore, at least some of the different line segment limits in Hα and Hβ Fig. 10), as seen in Mrk 110 (Kollatschny et al 2001). However, this is less likely to be true for Mrk 926: the He ii λ4686 line is centered on -10 800 km s −1 but the observed outer blue wing is centered on -9500 km s −1 (Fig.…”

Section: Rms Line Profilesmentioning

confidence: 98%

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Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

Kollatschny

Zetzl

2010

A&A

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Aims. We present results of an intensive spectroscopic variability campaign of the very broad-line Seyfert 1 galaxy Mrk 926. Our aim is to investigate the broad-line region (BLR) by studying the intensity and line profile variations of this galaxy on short timescales. Methods. High signal-to-noise ratio (S/N) spectra were taken with the 9.2 m Hobby-Eberly Telescope (HET) in identical conditions during two observing campaigns in 2004 and 2005. After the spectral reduction and internal calibration we achieved a relative flux accuracy of better than 1%. Results. The rms profiles of the very broad Balmer lines have shapes that differ from their mean line profiles, consisting of two inner (v ±6000 km s −1 ) and two outer (v ±6000 km s −1 ) line components in addition to a central component (v ±600 km s −1 ). These outer and inner line segments varied with different amplitudes during our campaign. The radius of the BLR is very small with an upper limit of 2 light-days for the Hβ BLR size. We derived an upper limit to the central black hole mass of M = 11.2 × 10 7 M . The 2-D cross-correlation functions CCF(τ, v) of Hβ and Hα are flat within the error limits. The response of the Balmer line segments with respect to continuum variations is different in the outer and inner wings of Hα and Hβ. This double structure in the response curves -of two separate inner and outer components -has also been seen in the rms line profiles. We conclude that the outer and inner line segments originate in different regions and/or under different physical conditions.

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Section: D Velocity Mapmentioning

confidence: 76%

Section: -D Ccf Of the Hα And Hβ Line Profilesmentioning

confidence: 95%

Section: D Velocity Mapmentioning

confidence: 97%

Section: Rms Line Profilesmentioning

confidence: 98%

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Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

Kollatschny

Zetzl

2010

A&A

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“…In his sample of ∼ 20 AGN he found firm evidence that both the [Fe VII] λ6087 and [Fe X] λ6375 emission lines varied (during a period of a few years) for only one source, namely, NGC 5548, which is the subject of this paper, and tentative evidence for another seven sources (including NGC 4151). Then, within a general optical variability campaign on the source Mrk 110 lasting for half a year, Kollatschny et al (2001) reported strong [Fe X] variations. More recently, follow-up optical spectroscopy of a handful of objects with unusually prominent coronal lines selected from the SDSS showed that in half of them the coronal lines strongly faded (by factors of ∼ 2 − 10), making these sources candidates for stellar tidal disruption events (Komossa et al 2009;Yang et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Strong variability of the coronal line region in NGC 5548

Landt¹,

Ward²,

Steenbrugge³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe VII] and X-ray O VII emission lines we estimate that the coronal line gas has a relatively low density of n e ∼ 10 3 cm −3 and a relatively high ionisation parameter of log U ∼ 1. The resultant distance of the coronal line gas from the ionising source of about eight light years places this region well beyond the hot inner face of the dusty torus. These results imply that the coronal line region is an independent entity. We find again support for the X-ray heated wind scenario of Pier & Voit; the increased ionising radiation that heats the dusty torus also increases the cooling efficiency of the coronal line gas, most likely due to a stronger adiabatic expansion. The much stronger coronal line variability of NGC 5548 relative to that of NGC 4151 can also be explained within this picture. NGC 5548 has much stronger coronal lines relative to the low ionisation lines than NGC 4151 indicating a stronger wind, in which case a stronger adiabatic expansion of the gas and so fading of the line emission is expected.

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AGN Reverberation Mapping

Bentz

2016

Astronomy at High Angular Resolution

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Reverberation mapping is now a well-established technique for investigating spatially-unresolved structures in the nuclei of distant galaxies with activelyaccreting supermassive black holes. Structural parameters for the broad emissionline region, with angular sizes of microarcseconds, can be constrained through the substitution of time resolution for spatial resolution. Many reverberation experiments over the last 30 years have led to a practical understanding of the requirements necessary for a successful program. With reverberation measurements now in hand for 60 active galaxies, and more on the horizon, we are able to directly constrain black hole masses, derive scaling relationships that allow large numbers of black hole mass estimates throughout the observable Universe, and begin investigating the detailed geometry and kinematics of the broad line region. Reverberation mapping is therefore one of the few techniques available that will allow a deeper understanding of the physical mechanisms involved in AGN feeding and feedback at very small scales, as well as constraints on the growth and evolution of black holes across cosmic time. In this contribution, I will briefly review the background, implementation, and major results derived from this high angular resolution technique.

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Short-term emission line and continuum variations in Mrk 110

Cited by 54 publications

References 23 publications

Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

Line profile and continuum variability in the very broad-line Seyfert galaxy Mrk 926

Strong variability of the coronal line region in NGC 5548

AGN Reverberation Mapping

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