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

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.

scholarly journals Radiation from the impact of broad-line region clouds onto AGN accretion disks

2020 ◽  
Vol 636 ◽  
pp. A92
Author(s):  
A. L. Müller ◽  
G. E. Romero
Keyword(s):  
Accretion Disk ◽  
Spectral Energy Distribution ◽  
Strong Shock ◽  
Shock Acceleration ◽  
Spectral Energy ◽  
Broad Line ◽  
Broad Line Region ◽  
Line Region ◽  
The Impact ◽  
Relativistic Particles

Context. Active galactic nuclei are supermassive black holes surrounded by an accretion disk, two populations of clouds, bipolar jets, and a dusty torus. The clouds move in Keplerian orbits at high velocities. In particular, the broad-line region (BLR) clouds have velocities ranging from 1000 to 10 000 km s−1. Given the extreme proximity of these clouds to the supermassive black hole, frequent collisions with the accretion disk should occur. Aims. The impact of BLR clouds onto the accretion disk can produce strong shock waves where particles might be accelerated. The goal of this work is to investigate the production of relativistic particles, and the associated non-thermal radiation in these events. In particular, we apply the model we develop to the Seyfert galaxy NGC 1068. Methods. We analyze the efficiency of diffusive shock acceleration in the shock of colliding clouds of the BLR with the accretion disk. We calculate the spectral energy distribution of photons generated by the relativistic particles and estimate the number of simultaneous impacts needed to explain the gamma radiation observed by Fermi in Seyfert galaxies. Results. We find that is possible to understand the measured gamma emission in terms of the interaction of clouds with the disk if the hard X-ray emission of the source is at least obscured between 20% and 40%. The total number of clouds contained in the BLR region might be between 3 × 108 and 6 × 108, which are values in good agreement with the observational evidence. The maximum energy achieved by the protons (∼PeV) in this context allows the production of neutrinos in the observing range of IceCube.

scholarly journals Feii strength in NLS1s – dependence on the viewing angle and FWHM(Hβ)

2019 ◽  
Vol 15 (S356) ◽  
pp. 332-334
Author(s):  
Swayamtrupta Panda ◽  
Paola Marziani ◽  
Bożena Czerny
Keyword(s):  
Main Sequence ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Broad Line ◽  
Viewing Angle ◽  
Black Hole Mass ◽  
Broad Line Region ◽  
Line Region ◽  
Disk Plane ◽  
Cloud Density

AbstractWe address the effect of orientation of the accretion disk plane and the geometry of the broad line region (BLR) in the context of understanding the distribution of quasars along their Main Sequence. We utilize the photoionization code CLOUDY to model the BLR, incorporating the ‘un-constant’ virial factor. We show the preliminary results of the analysis to highlight the co-dependence of the Eigenvector 1 parameter, RFeII on the broad HβFWHM (i.e. the line dispersion) and the inclination angle (θ), assuming fixed values for the Eddington ratio (Lbol/ LEdd), black hole mass (MBH), spectral energy distribution (SED) shape, cloud density (nH) and composition.†

scholarly journals Long-term optical spectroscopic variations in blazar 3C 454.3

2019 ◽  
Vol 631 ◽  
pp. A4 ◽  
Author(s):  
Krzysztof Nalewajko ◽  
Alok C. Gupta ◽  
Mai Liao ◽  
Krzysztof Hryniewicz ◽  
Maitrayee Gupta ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Line Emission ◽  
Spectral Energy ◽  
Broad Line ◽  
Line Flux ◽  
Broad Line Region ◽  
Relativistic Jet ◽  
Line Region ◽  
The Continuum

Aims. Characterisation of the long-term variations in the broad line region in a luminous blazar, where Comptonisation of broad-line emission within a relativistic jet is the standard scenario for production of γ-ray emission that dominates the spectral energy distribution. Methods. We analysed ten years of optical spectroscopic data from the Steward Observatory for the blazar 3C 454.3, as well as γ-ray data from the Fermi Large Area Telescope (LAT). The optical spectra are dominated by a highly variable non-thermal synchrotron continuum with a prominent Mg II broad emission line. The line flux was obtained by spectral decomposition including significant contribution from the Fe II pseudo-continuum. Three methods were used to characterise variations in the line flux: (1) stacking of the continuum-subtracted spectra, (2) subtracting the running mean light curves calculated for different timescales, and (3) evaluating potential time delays via the discrete correlation function (DCF). Results. Despite very large variations in the γ-ray and optical continua, the line flux changes only moderately (<0.1 dex). The data suggest that the line flux responds to a dramatic change in the blazar activity from a very high state in 2010 to a deep low state in 2012. Two interpretations are possible: either the line flux is anti-correlated with the continuum or the increase in the line luminosity is delayed by ∼600 days. If this time delay results from the reverberation of poorly constrained accretion disc emission in both the broad-line region (BLR) and the synchrotron emitting blazar zone within a relativistic jet, we would obtain natural estimates for the BLR radius RBLR, MgII ≳ 0.28 pc and for the supermassive black hole mass MSMBH ∼ 8.5 × 108 M⊙. We did not identify additional examples of short-term “flares” of the line flux, in addition to the previously reported case observed in 2010.

scholarly journals On the origin of GeV spectral break for Fermi blazars: 3C 454.3

2021 ◽  
Vol 502 (4) ◽  
pp. 5875-5881
Author(s):  
Shi-Ju Kang ◽  
Yong-Gang Zheng ◽  
Qingwen Wu ◽  
Liang Chen ◽  
Yue Yin
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Model Fitting ◽  
Spectral Energy ◽  
Power Law Distribution ◽  
Central Black Hole ◽  
Line Region ◽  
Spectral Break ◽  
Γ Ray ◽  
Radiation Area

ABSTRACT The GeV break in spectra of the blazar 3C 454.3 is a special observation feature that has been discovered by the Fermi-LAT. The origin of the GeV break in the spectra is still under debate. In order to explore the possible source of GeV spectral break in 3C 454.3, a one-zone homogeneous leptonic jet model and the McFit technique are utilized for fitting the quasi-simultaneous multiwaveband spectral energy distribution (SED) of 3C 454.3. The outside border of the broad-line region (BLR) and inner dust torus are chosen to contribute radiation in the model as external, seed photons to the external-Compton process, considering the observed γ-ray radiation. The combination of two components, namely the Compton-scattered BLR and dust torus radiation, assuming a broken power-law distribution of emitted particles, provides a proper fitting to the multiwaveband SED of 3C 454.3 detected 2008 August 3–September 2 and explains the GeV spectral break. We propose that the spectral break of 3C 454.3 may originate from an inherent break in the energy distribution of the emitted particles and the Klein–Nishina effect. A comparison is performed between the energy density of the ‘external’ photon field for the whole BLR UBLR achieved via model fitting and that constrained from the BLR data. The distance from the position of the γ-ray radiation area of 3C 454.3 to the central black hole could be constrained at ∼0.78 pc (∼4.00RBLR, the size of the BLR).

scholarly journals Excluding possible sites of high-energy emission in 3C 84

2020 ◽  
Vol 500 (4) ◽  
pp. 4671-4677
Author(s):  
Lena Linhoff ◽  
Alexander Sandrock ◽  
Matthias Kadler ◽  
Dominik Elsässer ◽  
Wolfgang Rhode
Keyword(s):  
Black Hole ◽  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Emission Region ◽  
Broad Line ◽  
Central Black Hole ◽  
Broad Line Region ◽  
Ring Geometry ◽  
Line Region

ABSTRACT The FR-I galaxy 3C 84, that is identified with the misaligned blazar NGC 1275, is well known as one of the very few radio galaxies emitting gamma-rays in the TeV range. Yet, the gamma-ray emission region cannot be pinpointed and the responsible mechanisms are still unclear. We calculate the optical absorption depth of high-energy photons in the broad-line region of 3C 84 depending on their energy and distance to the central black hole. Based on these calculations, a lower limit on the distance of the emission region from the central black hole can be derived. These lower limits are estimated for two broad-line region geometries (shell and ring) and two states of the source, the low state in 2016 October–December and a flare state in 2017 January. For the shell geometry, we can place the emission region outside the Ly α radius. For the ring geometry and the low flux activity, the minimal distance between the black hole, and the gamma-ray emission region is close to the Ly α radius. In the case of the flaring state (ring geometry), the results are not conclusive. Our results exclude the region near the central black hole as the origin of the gamma-rays detected by Fermi–LAT and Major Atmospheric Gamma-Ray Imaging Cherenkov. With these findings, we can constrain the theoretical models of acceleration mechanisms and compare the possible emission region to the source’s morphology resolved by radio images from the Very Long Baseline Array.

Estimating the Number of Broad-Line Region Clouds

1999 ◽  
Vol 194 ◽  
pp. 317-318
Author(s):  
M. Dietrich
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Filling Factor ◽  
Galactic Nuclei ◽  
Broad Line ◽  
Central Black Hole ◽  
Continuum Source ◽  
Broad Line Region ◽  
Line Region ◽  
Emission Line Spectrum

The observed emission-line spectrum of active galactic nuclei is consistent with cold dense gas photoionized by a central continuum source (cf. Ferland & Persson 1989). The estimate of the filling factor of the line-emitting region yields f˜10−6 only (cf. Osterbrock 1993) and motivated the picture of numerous clouds moving around a central black hole. Early estimates of the number of BLR clouds indicated a lower limit of 104 to 105 individual clouds (Capriotti et al. 1981; Atwood et al. 1982). Recently, Arav et al. (1998) estimated the number to be at least of the order of 107 discrete emitters. But the number and the nature of these clouds are still unknown.

scholarly journals The gravitational redshift in the broad line region of the active galactic nucleus Mrk 110

2006 ◽  
Vol 2 (S238) ◽  
pp. 369-370
Author(s):  
N. Gavrilović ◽  
L.Č Popović ◽  
W. Kollatschny
Keyword(s):  
Black Hole ◽  
Gravitational Field ◽  
Active Galactic Nucleus ◽  
Broad Line ◽  
Line Profiles ◽  
Central Black Hole ◽  
Broad Line Region ◽  
Line Region ◽  
Field Influence

AbstractWe used the long term spectroscopic observations of Mrk 110 (Hα and Hβ lines) to investigate the gravitational field influence on spectral line profiles. We found that effects of gravitational field can be measured and that the lines are more intense where the emission is originating close to the central black hole of Mrk 110.

scholarly journals Revealing the Broad Line Region of NGC 1275: The Relationship to Jet Power

2018 ◽  
Vol 869 (2) ◽  
pp. 143 ◽  
Author(s):  
Brian Punsly ◽  
Paola Marziani ◽  
Vardha N. Bennert ◽  
Hiroshi Nagai ◽  
Mark A. Gurwell
Keyword(s):  
Broad Line ◽  
Broad Line Region ◽  
Line Region ◽  
Ngc 1275 ◽  
The Relationship ◽  
Jet Power
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