Spectral Properties of Fermi Blazars and their Unification Schemes

Iyida, E. U.; Odo, F. C.; Chukwude, A. E.; Ubachukwu, A. A.

doi:10.1515/astro-2020-0015

Cited by 7 publications

(7 citation statements)

References 60 publications

(128 reference statements)

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“…We observed the existence of a selection of high frequency-peaking FSRQs (about 14 %) that have the same value of parameter in SS-CS and IC-SS planes. These few FSRQs are occupying the parameter space in a way that agrees with the unification scheme for radio galaxies, BL Lacs and FSRQs, (Iyida et al 2020;Odo & Aroh 2020). Actually, the sequence from Seyfert galaxy at low SS-CS plane to FSRQs at high SS-CS plane is in agreement with the evolution based unification scheme for Seyfert galaxy-BL Lacs-FSRQs unification such that at low synchrotron and inverse Compton energies, jetted AGNs are Seyfert galaxies though can metamorphose through BL Lac subclasses to FSRQs.…”

Section: Discussionsupporting

confidence: 54%

“…Thus, the continuous emission of blazars is observed to vary over many orders of magnitude in spectrum. Some authors modeled some parameters that depend on the broadband properties to study blazar unification scheme (Nalewajko & Gupta 2017;Iyida et al 2020). Of these proxy parameters often used is the composite spectral indices (a ij ), defined mainly between two wavebands (Iyida et al 2020) as:…”

Section: Methodology and Basic Assumptionsmentioning

confidence: 99%

“…Even though, the pattern of synchrotron as well as inverse Compton scattering by the leptonic model in ultra-relativistic jets that points close to an observer's line of sight has been used in modeling the SEDs of blazars, many fundamental issues remain, including the properties of these sources in the low and high energy components. Conversely, there seems to be a general agreement that appears to support a unification scheme with interesting results, indicating orientation links between blazar subclasses and radio galaxies (Fan et al 2011;Pei et al 2019;Iyida et al 2020). Precisely, latest studies using the Fermi large area telescope (Fermi-LAT) sample suggest that blazar unification can be extended to radio galaxies by simply invoking an orientation sequence (Pei et al 2020a;Iyida et al 2021a).…”

Section: Introductionmentioning

confidence: 92%

“…This is called the unification model via blazar sequence. This type of connection among the blazar subclasses has been topical in blazar astronomy for over two decades and a number of results has been recorded (Cellone et al 2007;Gaur et al 2010;Ackermann et al 2011;Urry 2011;Fan et al 2016;Iyida et al 2019;Pei et al 2019Pei et al , 2020a. Nevertheless, the phenomenon of blazar astronomy is sometimes explained in the context of relativistic beaming effect (Kollgaard 1996;Wu et al 2014) due to the fact that the radiations from the jets are assumed to always be directed close to an observer's line of sight.…”

Section: Introductionmentioning

confidence: 97%

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On the unified view of extragalactic sources based on their broadband emission properties

2021

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Our understanding of the unification of jetted active galactic nuclei (AGNs) has advanced greatly as the size of extragalactic sources increased. In this paper, based on the large sample of radio sources, we compiled 680 blazars (279 flat spectrum radio quasars (FSRQs) and 401 BL Lacertae (BL Lacs)) from the 3FGL sample and 64 Seyfert galaxies (3 Narrow-line, 34 and 27 regular Seyfert 1 and Seyfert 2 respectively) from the INTEGRAL/IBIS survey to statistically test the relationship between Seyfert galaxies and the blazar samples of FSRQs and BL Lacs. We compute the synchrotron (SS), Compton (CS) and inverse Compton (IC) continuous spectra from the low energy components of radio to X-ray, radio to c-ray and the high energy component of X-ray to c-ray bands, respectively. Results show from the distributions of the continuous spectra that Seyfert galaxies form the tail of the distributions, suggestive of similar underlying history and evolution. A two-sample Kolmogorov-Smirnov (K-S) test of the continuous spectra showed that Seyfert galaxies differ from BL Lacs and FSRQs in the low energy components of the spectra, while there is no clear difference between them in the high energy component, which implies that high energy emissions in Seyfert galaxies, BL Lacs and FSRQs may be as a result of the same emission mechanism. There is a regular sequence of the distributions on SS-CS and IC-CS planes in each individual subsample. Linear regression analyses of our sample yield significant positive correlations (r C 0.60) between SS-CS and IC-CS data. This upturns into an anti-correlation (r [ -0.60) in IC-SS data. These results are not only consistent with unified scheme for blazars but also show that Seyfert galaxies can be unified with the classical radio-loud AGNs counterparts.

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Section: Discussionsupporting

confidence: 54%

Section: Methodology and Basic Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

On the unified view of extragalactic sources based on their broadband emission properties

2021

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“…Urry and Padovani 1995;Ghisellini et al 2009;Sbarrato et al 2014), relativistic beaming and orientation effects between blazars and RGs are attracting the attention of researchers, producing new results (e.g. Fan et al 2011;Pei et al 2010;Iyida et al 2020;Ye and Fan, 2020). Specifically, current studies using the Fermi-LAT data suggest that HBLs -LBLs -IBLs -FSRQs sequence can be extended to RGs (e.g.…”

Section: Introductionmentioning

confidence: 99%

Orientation and Beaming Effects in active galactic nuclei: Implication for radio galaxy - Blazar Evolution

Iyida

Onah²,

Eya

et al. 2023

Preprint

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The orientation and evolution based on unified scheme for jetted extragalactic radio sources posits that BL Lacertae objects (BLs), flat-spectrum radio quasars (FSRQs) and normal radio galaxies (RGs) represent increasingly misaligned populations of active galactic nuclei (AGNs). Using compiled radio, X-ray and γ-ray data of 397 blazars and 110 RGs from the Fermi Large Area Telescope (Fermi-LAT) catalogue, we computed the viewing angles, γ-ray core-dominance parameter and γ-ray emission components in order to study the consequences of orientation and relativistic beaming effects on γ-ray properties of RGs, BLs and FSRQs. Our results show continuous distributions of core-dominance parameters (X-ray, RX and γ-ray, Rγ) from RGs at low values, largest viewing angles to FSRQs at high values and BLs subsets with the least values. The difference on the plane is significantly larger for FSRQs and BLs than for RGs, indicating an evolutionary link between them. A two-sample Wilcoxon rank-sum and Kolmogorov-Smirnov tests carried out on our data suggest that the probabilities of the distribution of RX and Rγ of RGs and blazar types to come from the same parent distribution are pWRS ∼ 0 and pK−S < 10-5, suggestive of stronger beaming effects in blazars than in RGs. There is a significant correlation (r > 0.60) between log Rr - log RX for the combined sample types. Furthermore, a significant anti-correlation (r ∼ -0.80) exists in the log Rγ - log Lγ,un plot which is indicative of evolutionary sequence via relativistic beaming model. These results imply that the evolutionary track of jetted AGNs is RGs - BLs FSRQs

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Investigating possible unification of Seyfert galaxies and blazars in Fermi‐Large Area Telescope sample

2021

Self Cite

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Statistical analyses are invaluable methods used to understand intrinsic emission processes and the unification of extragalactic radio sources. In this paper, we collected radio, X-ray, and γ-ray data of blazars from the Fermi Large Area Telescope (Fermi-LAT) and Seyfert galaxies from the INTEGRAL/IBIS survey and investigated the relationship between the emission properties of Seyfert galaxies and blazar subclasses of flat-spectrum radio quasars (FSRQs) and BL Lac objects (BL Lacs). The results show from the average values that these objects follow a sequence that is indicative of probable Seyfert galaxies-BL Lacs-FSRQs unification. We discovered that Seyfert galaxies, BL Lacs, and FSRQs share similar emission characteristics in X-ray luminosity (L X-ray ), suggestive of fundamental connection while the γ-ray (L γ-ray ) and radio (L radio ) luminosities of Seyfert galaxies are the least powerful, signifying an evolving structure. From the two-dimensional Kolmogorov-Smirnov (K − S) test, we found that Seyfert galaxies differ from the blazar subclasses in L radio while there is no significant difference between them in L X-ray and L γ-ray which implies that high-energy emissions in Seyfert galaxies and blazar subclasses may come from the same emission mechanism. Significant positive correlations (with coefficient r > 0.60) exist between the high-energy luminosities (X-ray and γ-ray) and the low-energy components (radio) within the whole sample of blazars and Seyfert galaxies implying a form of connection between them. These results are not only consistent with the prediction of the unified scheme for blazars but also show that Seyfert galaxies have an evolutionary link with blazar subclasses.

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Spectral Properties of Fermi Blazars and their Unification Schemes

Cited by 7 publications

References 60 publications

On the unified view of extragalactic sources based on their broadband emission properties

On the unified view of extragalactic sources based on their broadband emission properties

Orientation and Beaming Effects in active galactic nuclei: Implication for radio galaxy - Blazar Evolution

Investigating possible unification of Seyfert galaxies and blazars in Fermi‐Large Area Telescope sample

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