scholarly journals Modeling the spectral energy distribution of 3C 454.3 in a “flat” broad-line region scenario

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
Maichang Lei ◽  
Jiancheng Wang
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Broad Line ◽  
Broad Line Region ◽  
Line Region

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 The Infrared, Optical and Ultraviolet Properties of Active Nuclei

1984 ◽  
Vol 110 ◽  
pp. 73-83
Author(s):  
Marie-Helene Ulrich
Keyword(s):  
Energy Distribution ◽  
Temporal Variations ◽  
Optical Polarization ◽  
Broad Line ◽  
Continuum Spectrum ◽  
Broad Line Region ◽  
Line Region ◽  
The Continuum

We review the important properties of active nuclei, in particular (i) the optical polarization and its relation to the jets found by VLBI (ii) the energy distribution and the temporal variations of the continuum spectrum and (iii) the distribution of the matter in the broad line region.

scholarly journals Investigation of the γ-ray spectrum of CTA 102 during the exceptional flaring state in 2016–2017

2020 ◽  
Vol 635 ◽  
pp. A25 ◽  
Author(s):  
N. Sahakyan
Keyword(s):  
Energy Distribution ◽  
Power Law ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
Extended Period ◽  
Spectral Energy ◽  
Large Area ◽  
Inverse Compton Scattering ◽  
Line Region ◽  
Photon Index

The flat spectrum radio quasar CTA 102 entered an extended period of activity from 2016 to 2017 during which several strong γ-ray flares were observed. By using Fermi large area telescope data, a detailed investigation of γ-ray spectra of CTA 102 during the flaring period was performed. In several periods, the γ-ray spectrum is not consistent with a simple power-law, having a hard photon index with an index of ∼(1.8−2.0) that shows a spectral cut-off around an observed photon energy of ∼(9−16) GeV. The internal γ-ray absorption via photon-photon pair production on the broad-line-region-reflected photons cannot account for the observed cut-off and break even if the emitting region is very close to the central source. This cut-off and break are likely due to a similar intrinsic break in the energy distribution of emitting particles. The origin of the spectral break is investigated through the multiwavelength modeling of the spectral energy distribution in considering a different location for the emitting region. The observed X-ray and γ-ray data is modeled as inverse Compton scattering of synchrotron and/or external photons on the electron population that produces the radio-to-optical emission, which allowed to constrain the power-law index and cut-off energy in the electron energy distribution. The obtained results are discussed in the context of a diffusive acceleration of electrons in the CTA 102 jet.

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 A new model for the infrared emission of IRAS F10214+4724

2011 ◽  
Vol 7 (S284) ◽  
pp. 205-209
Author(s):  
Andreas Efstathiou ◽  
Natalie Christopher ◽  
Aprajita Verma ◽  
Ralf Siebenmorgen
Keyword(s):  
Energy Distribution ◽  
Gravitational Lensing ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Infrared Emission ◽  
Spectral Energy ◽  
New Model ◽  
Average Spectrum ◽  
Line Region ◽  
The Galaxy

AbstractWe present a new model for the infrared emission of the high redshift hyperluminous infrared galaxy IRAS F10214+4724 which takes into account recent photometric data from Spitzer and Herschel that sample the peak of its spectral energy distribution. We first demonstrate that the combination of the AGN tapered disc and starburst models of Efstathiou and coworkers, while able to give an excellent fit to the average spectrum of type 2 AGN measured by Spitzer, fails to match the spectral energy distribution of IRAS F10214+4724. This is mainly due to the fact that the ν Sν distribution of the galaxy falls very steeply with increasing frequency (a characteristic of heavy absorption by dust) but shows a silicate feature in emission. We propose a model that assumes two components of emission: clouds that are associated with the narrow-line region and a highly obscured starburst. The emission from the clouds must suffer significantly stronger gravitational lensing compared to the emission from the torus to explain the observed spectral energy distribution.

scholarly journals Influence of Microlensing on Spectral Anomalies of the Lensed Objects

2011 ◽  
Vol 20 (3) ◽  
Author(s):  
S. Simić ◽  
L. Č. Popović ◽  
P. Jovanović
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Angular Size ◽  
Black Body ◽  
Spectral Energy

AbstractHere we consider the influence of microlensing on the spectrum of a lensed object with the angular size 5 μas accepting that the composite emission of this object originates from three different regions arranged around its center. We assume that the lensed object has three concentric regions with a black-body emission; the temperatures of these regions are 10 000 K, 7500 K and 5000 K. We investigate how the integral spectral energy distribution (SED) of such stratified source changes due to microlensing by a group of solarmass stars. We find that the SED and flux ratios in the photometric B, V and R passbands show considerable changes during a microlens event. This indicates that the flux anomaly observed in some lensed quasars may be caused by microlensing of a stratified object.

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