The structure of the broad-line region in the Seyfert galaxy Markarian 590

One of the primary goals of AGN variability studies has been to determine the size of broad-line region (BLR) through the reverberation mapping technique. In a recent international multiwavelength spectroscopic monitoring campaign, NGC 4151 has been observed intensively by ground-based telescopes for a period of over 2 months, with a typical temporal resolution of 1 day. The main result from this optical campaign is that finding the variation in the emission line flux (Hβ or Hα) lagging the continuum by 0-3 days (1993 campaign: Kaspi et al. 1996). This is in contrast to the past results in which a time lag of 9±2 days was found for the same emission line (1988 campaign: Maoz et al. 1991). Such a BLR “size problem” may be caused by a different variability timescale of the ionizing continuum or a real change in BLR gas distribution in the 5.5 yr interval between the two watch campaigns. In order to clarify which of the two possibilities is most likely the real case, we performed further reverberation analysis on both optical datasets.

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Reverberation mapping analysis of the broad-line region in Seyfert galaxy NGC 4151

Chinese Astronomy and Astrophysics ◽

10.1016/s0275-1062(98)00051-4 ◽

1998 ◽

Vol 22 (4) ◽

pp. 395-408

Author(s):

Sui-jian Xue ◽

Fu-zhen Cheng

Keyword(s):

Seyfert Galaxy ◽

Broad Line ◽

Reverberation Mapping ◽

Ngc 4151 ◽

Broad Line Region ◽

Line Region ◽

Mapping Analysis

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Optical Spectrum Variability of Seyfert Galaxy Nuclei

Highlights of Astronomy ◽

10.1017/s1539299600004524 ◽

1980 ◽

Vol 5 ◽

pp. 631-639 ◽

Cited By ~ 6

Author(s):

A. G. de Bruyn

Keyword(s):

Optical Spectrum ◽

Seyfert Galaxy ◽

Optical Emission ◽

Emission Lines ◽

Optical Variability ◽

Broad Line ◽

Broad Line Region ◽

Line Region ◽

Photo Ionization ◽

The Continuum

In this contribution I will present some results of a program aimed at determining the optical variability characteristics of Seyfert galaxy nuclei. It has been known for more than a decade that the continuous, non-stellar light of Seyfert nuclei can vary significantly on a time scale of months to years (see, e.g., Lyutyi, 1973, 1977; Penston et al., 1974; Penfold, 1979). In recent years there also have been various reports of variations in the intensity of the broad optical emission lines (Boksenberg and Netzer, 1977; Tohline and Osterbrock, 1976) following the pioneering work by Souffrin et al. (1973) and Cherepashchuk and Lyutyi (1973). However, very little is known on the details of the continuum variations and how they relate to the line variability. Such information could provide valuable constraints on the fashionable photo-ionization models for the broad line region (BLR) and the structure of the latter.

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LOCATING THE BLAZAR EMISSION SITE WITH FERMI VARIABILITY

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194512004394 ◽

2012 ◽

Vol 08 ◽

pp. 37-42

Author(s):

MARKOS GEORGANOPOULOS ◽

AMANDA DOTSON ◽

DEMOSTHENES KAZANAS ◽

ERIC PERLMAN

Keyword(s):

Energy Dissipation ◽

Broad Line ◽

Jet Formation ◽

Spectral Variability ◽

Ongoing Debate ◽

Broad Line Region ◽

Photon Field ◽

First Case ◽

Line Region

This work presents a method for settling the following ongoing debate: is the GeV emission of powerful blazars produced inside the sub-pc size broad line region (BLR) or further out at scales of ~ 10 pc where the IR photon field of the dusty molecular torus dominates over that the UV field of the BLR? In the first case the GeV emission is most probably external Compton (EC) scattering of the ~ 10 eV BLR photons21, while in the second the seed photons for the EC GeV emission are the ~ 0.1 eV photons of the dust9 in the molecular torus8. The issue of the energy dissipation location is connected to the jet formation and collimation process25 and, as we argue here, can be resolved with Fermi spectral variability observations.

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Hadronuclear interpretation of the possible neutrino emission from PKS B1424-418, GB6 J1040+0617 and PKS 1502+106

Research in Astronomy and Astrophysics ◽

10.1088/1674-4527/21/12/305 ◽

2022 ◽

Vol 21 (12) ◽

pp. 305

Author(s):

Ze-Rui Wang ◽

Rui Xue

Keyword(s):

Detection Rate ◽

Spectral Energy Distribution ◽

Spectral Energy ◽

Broad Line ◽

Central Black Hole ◽

Proton Proton ◽

Broad Line Region ◽

Neutrino Detection ◽

Line Region ◽

Jet Power

Abstract In addition to neutrino event IceCube-170922A which is observed to be associated with a γ-ray flare from blazar TXS 0506+056, there are also several neutrino events that may be associated with blazars. Among them, PKS B1424-418, GB6 J1040+0617 and PKS 1502+106 are low synchrotron peaked sources, which are usually believed to have the broad line region in the vicinity of the central black hole. They are considered as counterparts of IceCube event 35, IceCube-141209A and IceCube-190730A, respectively. By considering the proton-proton (pp) interactions between the dense gas clouds in the broad line region and the relativistic protons in the jet, we show that the pp model that is applied in this work can not only reproduce the multi-waveband spectral energy distribution but also suggest a considerable annual neutrino detection rate. We also discuss the emission from the photopion production and Bethe-Heitler pair production with a sub-Eddington jet power that is suggested in our model and find that it has little effect on the spectrum of total emission for all of three sources.

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