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

Kollatschny, W.; Zetzl, M.

doi:10.1051/0004-6361/200913463

Cited by 13 publications

(24 citation statements)

References 45 publications

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“…Intriguingly, there is further evidence for a possible weak absorption line at ∼ 7.3 keV in X-rays, indicating a mildly relativistic outflow with v= -11 000 km s −1 . A blue absorption component in the Balmer lines at v∼ -11 000 km s −1 like this has also been detected in another very broad-line AGN (Mrk 926) (Kollatschny 2010), indicating a high-velocity outflow component.…”

Section: Optical Spectrum: Extremely Broad and Double-peakedsupporting

confidence: 67%

Optical and X-ray discovery of the changing-look AGN IRAS 23226-3843 showing extremely broad and double-peaked Balmer profiles

Kollatschny

Grupe

Parker

et al. 2020

A&A

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Aims. We detected a very strong X-ray decline in the galaxy IRAS 23226-3843 within the XMM-Newton slew survey in 2017. Subsequently, we carried out multi-band follow-up studies to investigate this fading galaxy in more detail. Methods. We took deep follow-up Swift, XMM-Newton, and NuSTAR observations in combination with optical SALT spectra of IRAS 23226-3843 in 2017. In addition, we reinspected optical, UV, and X-ray data that were taken in the past. Results. IRAS 23226-3843 decreased in X-rays by a factor of more than 30 with respect to ROSAT and Swift data taken 10 to 27 years before. The broadband XMM-Newton/NuSTAR spectrum is power-law dominated, with a contribution from photoionized emission from cold gas, likely the outer accretion disk or torus. The optical continuum decreased by 60% and the Balmer line intensities decreased by 50% between 1999 and 2017. The optical Seyfert spectral type changed simultaneously with the X-ray flux from a clear broad-line Seyfert 1 type in 1999 to a Seyfert 1.9 type in 2017. The Balmer line profiles in IRAS 23226-3843 are extremely broad. The profiles during the minimum state indicate that they originate in an accretion disk. The unusual flat Balmer decrement Hα/ Hβ with a value of 2 indicates a very high hydrogen density of n H > 10 11 cm −3 at the center of the accretion disk. IRAS 23226-3843 shows unusually strong FeII blends with respect to the broad line widths, in contrast to what is known from Eigenvector 1 studies.

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Section: Optical Spectrum: Extremely Broad and Double-peakedsupporting

confidence: 67%

Optical and X-ray discovery of the changing-look AGN IRAS 23226-3843 showing extremely broad and double-peaked Balmer profiles

Kollatschny

Grupe

Parker

et al. 2020

A&A

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“…Great care was taken to ensure high-quality intensity and wavelength calibrations to keep the intrinsic measurement errors very low (Kollatschny et al, 2001(Kollatschny et al, , 2003(Kollatschny et al, , 2010. Our galaxy spectra as well as our calibration star spectra were not always taken under photometric conditions.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…In this section we investigate in more detail the profile variations of the Balmer and helium lines in 3C 120. We proceed in the same way as for the line profile variations in Mrk 110 (Kollatschny & Bischoff 2002;Kollatschny 2003) and Mrk 926 (Kollatschny & Zetzl 2010). We sliced the velocity profiles of the Balmer and helium lines into velocity segments of widths ∆v = 400 km s −1 .…”

Section: D Ccf Of the Balmer (Hα Hβ Hγ) And Helium I Ii Line Profmentioning

confidence: 99%

Broad-line region structure and kinematics in the radio galaxy 3C 120

Kollatschny

Ulbrich

Zetzl

et al. 2014

A&A

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Context. Broad emission lines originate in the surroundings of supermassive black holes in the centers of active galactic nuclei (AGN). These broad-line emitting regions are spatially unresolved even for the nearest AGN. The origin and geometry of broad-line region (BLR) gas and their connection with geometrically thin or thick accretion disks is of fundamental importance for the understanding of AGN activity. Aims. One method to investigate the extent, structure, and kinematics of the BLR is to study the continuum and line profile variability in AGN. We selected the radio-loud Seyfert 1 galaxy 3C 120 as a target for this study. Methods. We took spectra with a high signal-to-noise ratio of 3C 120 with the 9.2 m Hobby-Eberly Telescope between Sept. 2008 and March 2009. In parallel, we photometrically monitored the continuum flux at the Wise observatory. We analyzed the continuum and line profile variations in detail (1D and 2D reverberation mapping) and modeled the geometry of the line-emitting regions based on the line profiles. Results. We show that the BLR in 3C 120 is stratified with respect to the distance of the line-emitting regions from the center with respect to the line widths (FWHM) of the rms profiles and with respect to the variability amplitude of the emission lines. The emission line wings of Hα and Hβ respond much faster than their central region. This is explained by accretion disk models. In addition, these lines show a stronger response in the red wings. However, the velocity-delay maps of the helium lines show a stronger response in the blue wing. Furthermore, the He ii λ4686 line responds faster in the blue wing in contradiction to observations made one and a half years later when the galaxy was in a lower state. The faster response in the blue wing is an indication for central outflow motions when this galaxy was in a bright state during our observations. The vertical BLR structure in 3C 120 coincides with that of other AGN. We confirm the general trend: the emission lines of narrow line AGN originate at larger distances from the midplane than AGN with broader emission lines.

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“…Note here that quasars very often show variability in the broad line spectra, an amplification in the line intensity as the response to outburst in the continuum source emission (Gaskell & Sparke, 1986;Peterson & Gaskell, 1986;Peterson et al, 2004). But some AGNs, additionally to the line flux variation, show a very high variability in the line shape, as e.g., Mrk 926 (Kollatschny & Zetzl, 2010) where blue wing shows higher variation than red one. Another example is, well known AGN, NGC 4151 that shows very huge changes in the line profile during an 11-year monitoring period (see Shapovalova et al, 2010b).…”

Section: Variability Of the Broad Line Profiles And Smbsmentioning

confidence: 99%

Super-massive binary black holes and emission lines in active galactic nuclei

Popović

2012

New Astronomy Reviews

117

130

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It is now agreed that mergers play an essential role in the evolution of galaxies and therefore that mergers of supermassive black holes (SMBHs) must have been common. We see the consequences of past supermassive binary black holes (SMBs) in the light profiles of so-called 'core ellipticals' and a small number of SMBs have been detected. However, the evolution of SMBs is poorly understood. Theory predicts that SMBs should spend a substantial amount of time orbiting at velocities of a few thousand kilometers per second. If the SMBs are surrounded by gas observational effects might be expected from accretion onto one or both of the SMBHs. This could result in a binary Active Galactic Nucleus (AGN) system. Like a single AGN, such a system would emit a broad band electromagnetic spectrum and broad and narrow emission lines.The broad emission spectral lines emitted from AGNs are our main probe of the geometry and physics of the broad line region (BLR) close to the SMBH. There is a group of AGNs that emit very broad and complex line profiles, showing two displaced peaks, one blueshifted and one redshifted from the systemic velocity defined by the narrow lines, or a single such peak. It has been proposed that such line shapes could indicate an SMB system. We discuss here how the presence of an SMB will affect the BLRs of AGNs and what the observational consequences might be.We review previous claims of SMBs based on broad line profiles and find that they may have non-SMB explanations as a consequence of a complex BLR structure. Because of these effects it is very hard to put limits on the number of SMBs from broad line profiles. It is still possible, however, that unusual broad line profiles in combination with other observational effects (line ratios, quasi-periodical oscillations, spectropolarimetry, etc.) could be used for SMBs detection.Some narrow lines (e.g., [O III]) in some AGNs show a double-peaked profile. Such profiles can be caused by streams in the Narrow Line Region (NLR), but may also indicate the presence of a kilo-parsec scale mergers. A few objects indicated as doublepeaked narrow line emitters are confirmed as kpc-scale margers, but double-peaked narrow line profiles are mostly caused by the complex NLR geometry.We briefly discuss the expected line profile of broad Fe Kα that probably originated in the accretion disk(s) around SMBs. This line may also be very complex and indicate the complex disk geometry or/and an SMB presence.Finally we consider rare configurations where a SMB system might be gravitationally lensed by a foreground galaxy, and discuss the expected line profiles in these systems.

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

Cited by 13 publications

References 45 publications

Optical and X-ray discovery of the changing-look AGN IRAS 23226-3843 showing extremely broad and double-peaked Balmer profiles

Optical and X-ray discovery of the changing-look AGN IRAS 23226-3843 showing extremely broad and double-peaked Balmer profiles

Broad-line region structure and kinematics in the radio galaxy 3C 120

Super-massive binary black holes and emission lines in active galactic nuclei

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