Multiwavelength Variability Analysis of 3C 279

Patiño-Álvarez, V.; Fernandes, Sunil; Chavushyan, V.; López-Rodríguez, E.; Schlegel, Eric M.; Carrasco, L.; Valdés, J. R.; Carramiñana, A.

doi:10.3389/fspas.2017.00047

Cited by 5 publications

(6 citation statements)

References 8 publications

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“…This change of spectral index is expected in the scenario of a shift in the energy distribution of the electron population, to lower energies, due to an increase in the cooling via synchrotron emission. This further supports the hypothesis by Patiño-Álvarez et al (2017), andPatiño-Álvarez et al (2018), that an increase in the Lorentz factor of the jet, causes an increase in the synchrotron emission, while at the same time increasing the gammaray opacity due to electron-positron pair production. This scenario also explains the timing of the spectral index change in the radio emission.…”

Section: Discussionsupporting

confidence: 89%

Is there a non-stationary γ-ray emission zone 42 pc from the 3C 279 core?

Patiño-Álvarez

Dzib

Lobanov

et al. 2019

A&A

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We investigate the relationship between the variable gamma-ray emission and jet properties in the blazar 3C 279, by combining the Fermi/LAT data spanning a period of eight years with concurrent radio measurements made at multiple epochs with VLBA at 15 and 43 GHz within the MOJAVE and VLBA-BU monitoring programs. The aim of this paper is to compare the flux variability of the different components found in the VLBA observations, to the variability in the gamma-rays. This analysis helps to investigate whether any of the jet components can be associated with the gamma-ray variability. Through Spearman rank correlation we found that the gamma-ray variability is correlated with a particular region (feature B, in the MOJAVE images) downstream from the observed base (core) of the jet. This jet component is therefore a likely location at which an important fraction of the variable gamma-ray emission is produced. We also calculated the average proper motion of the component with respect to the VLBA core and found that it moves at an apparent superluminal velocity of (3.70 ± 0.35)c, implying that one of the gamma-ray emission zones is not stationary. This jet component is also found between 6.86 mas and 8.68 mas, which translates to a distance from the radio core of at least 42 pc.

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Section: Discussionsupporting

confidence: 89%

Is there a non-stationary γ-ray emission zone 42 pc from the 3C 279 core?

Patiño-Álvarez

Dzib

Lobanov

et al. 2019

A&A

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“…Both the flux and spectral shape of blazars are variable with different timescales ranging from minutes to days (Gu et al 2006;Aharonian et al 2007;Gu & Ai 2011;Isler et al 2013;León-Tavares et al 2013;Hayashida et al 2015;Paliya et al 2017b;Patiño-Álvarez et al 2017;Gupta 2018;Nalewajko et al 2019;Sarkar et al 2019;Chavushyan et al 2020). Furthermore, blazars also feature flat radio spectra at GHz frequencies (Healey et al 2007;Massaro et al 2013;Petrov et al 2013;Nori et al 2014;Schinzel et al 2015Schinzel et al , 2017Giroletti et al 2016), coupled with polarized emission detected up to optical wavelengths (Poutanen 1994;Park et al 2018;Mandarakas et al 2019), and with peculiar mid-IR colors (Massaro et al 2011(Massaro et al , 2012bD'Abrusco et al 2012D'Abrusco et al , 2013) not ascribable to dust emission.…”

Section: Introductionmentioning

confidence: 99%

An Optical Overview of Blazars with LAMOST. II. Gamma-Ray Blazar Candidates and Updated Classifications

Peña-Herazo

Massaro

et al. 2021

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Blazars represent the dominant class of associated γ-ray sources detected by the Fermi Large Area Telescope (LAT). However, in the more recent release of the Fourth Fermi-LAT Point Source Catalog (4FGL), ∼25% of the sources associated with lower-energy counterparts show a multifrequency behavior similar to that of blazars, but lacks an optical spectroscopic confirmation of their nature and are therefore classified as Blazar Candidates of Uncertain Type (BCUs). A particularly challenging task in blazar studies is to classify these BCUs and, when possible to estimate their redshifts, in particular for BL Lac objects, characterized by almost featureless optical spectra with only weak emission lines. Continuing our study of blazars with Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) optical spectral data, we perform an extensive search for optical spectra available in the LAMOST Data Release 6 archive. Our aim is confirming the blazar nature of BCUs and to test if new data can allow us to get a redshift estimate for BL Lac objects that lack measurement, as well as to search for and discover changing-look blazars. We selected sources out of the 4FGL catalog, the list of targets from our follow-up spectroscopic campaign of unidentified and/or unassociated γ-ray sources, and the Roma-BZCAT multifrequency catalog of blazars, finding a total of 42 sources with available LAMOST DR6 spectra. We confirmed the blazar-like nature of four blazar candidates . For the remaining 37 sources we confirm their previous classification.

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“…Moreover, as an application of radio astronomy, studying the behavior of the radio luminosity function (e.g., Willott (2001 ); Dunlop & Peacock (1990 )) plays a significant role in understanding the formation and evolution of radio galaxies and the cosmological evolution of radio sources, which in turn help to uncover the physics of the early universe. Quasars, an extremely luminous compact region thought to reside at the center of galaxies, are distant astronomical objects that belong to a subclass of AGNs (e.g., Padovani et al (2017 ); Patiño-Álvarez et al (2017 ) ;Fernandes et al (2017 ); Courvoisier (1987 )). Flat spectrum radio quasars (hereinafter FSRQs), which include both highand low-polarization quasars (hereinafter HPQs and LPQs, respectively), along with BL Lac objects, form a subset of AGNs known as blazars.…”

Section: Introductionmentioning

confidence: 99%

“…Quasars, an extremely luminous compact region thought to reside at the center of galaxies, are distant astronomical objects that belong to a subclass of AGNs (e.g., Padovani et al (2017 ); Patiño-Álvarez et al (2017 ); Fernandes et al (2017 ); Courvoisier (1987 )). Flat spectrum radio quasars (hereinafter FSRQs), which include both highand low-polarization quasars (hereinafter HPQs and LPQs, respectively), along with BL Lac objects, form a subset of AGNs known as blazars.…”

Section: Introductionmentioning

confidence: 99%

“…Radio-loud quasars/blazars show some of the most violent high-energy phenomena observed in AGNs to date. They emit radiation across the electromagnetic spectrum, from the radio to X-rays and/or gamma rays (e.g., Padovani et al (2017 ); Patiño-Álvarez et al (2017 ); Fernandes et al (2017 ); Villata et al (2009 ); Courvoisier (1987 )) and have the characteristics of very high luminosity, nonthermal radiation, strong radio emission, and large flux fluctuations and have been known as highly variable energetic sources across the electromagnetic spectrum though most (if not all) of them are strongly variable in a very short time scale at higher frequencies (Lawson 1999;Courvoisier 1988 ;Wehrle 1998 ;Ulrich 1997 ;Netzer et al 1996 ;Dondi & Ghisellini 1995 ;Cotton 1979); moreover, high and variable polarization and superluminal motion are characteristics of blazars. The low-energy blazar emission is thought to be the result of electron synchrotron radiation, with the peak frequency reflecting the maximum energy at which electrons can be accelerated ( Petropoulou & Dimitrakoudis 2015 ).…”

Section: Introductionmentioning

confidence: 99%

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Cosmological Evolution of Quasar Radio Emission in the View of Multifractality

Belete

Femmam

Tornikosk

et al. 2019

ApJ

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Variations in scaling behavior in the flux and emissions of distant astronomical sources with respect to their cosmic time are important l phenomena that can provide valuable information about the dynamics within the sources and their cosmological evolution with time. Different studies have been applying linear analysis to understand and model quasars' light curves. Here, we study the multifractal behavior of selected quasars' radio emissions in their observed frame (at 22 and 37 GHz bands) and and their rest frame. To this end, we apply the wavelet transform-based multifractal analysis formalism called wavelet transform modulus maxima. In addition, we verify whether the autoregressive integrated moving average (ARIMA) models fit our data or not. In our work, we observe strong multifractal behavior for all the sources. Additionally, we find that the degree of multifractality is strongly similar for each source and significantly different between sources at 22 and 37 GHz. This similarity implies that the two frequencies have the same radiation region and mechanism, whereas the difference indicates that the sources have intrinsically different dynamics. Furthermore, we show that the degree of multifractality is the same in the observed and rest frames of the quasars, i.e., multifractality is an intrinsic property of radio quasars. Finally, we show that the ARIMA models fit the 3C 345 quasar at 22 GHz and partially fit most of the time series with the exception of the 3C 273 and 3C 279 quasars at 37 GHz, for which the models are found to be inadequate.

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Multiwavelength Variability Analysis of 3C 279

Cited by 5 publications

References 8 publications

Is there a non-stationary γ-ray emission zone 42 pc from the 3C 279 core?

Is there a non-stationary γ-ray emission zone 42 pc from the 3C 279 core?

An Optical Overview of Blazars with LAMOST. II. Gamma-Ray Blazar Candidates and Updated Classifications

Cosmological Evolution of Quasar Radio Emission in the View of Multifractality

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