The Changing-look Blazar B2 1420+32

Mishra, Hora D.; Dai, Xinyu; Chen, Ping; Cheng, Ji-Gui; Jayasinghe, T.; Tucker, M. A.; Vallely, P.; Bersier, D.; Bose, S.; Do, A.; Dong, Subo; Holoien, T. W. S.; Huber, M. E.; Kochanek, C. S.; Liang, En‐Wei; Payne, A. V.; Prieto, J. L.; Shappee, B. J.; Stanek, K. Z.; Bhatiani, Saloni; Cox, J. A.; DeFrancesco, Cora; Shen, Zhi-Qiang; Thompson, Todd A.; Wang, Junfeng

doi:10.3847/1538-4357/abf63d

Cited by 20 publications

(23 citation statements)

References 75 publications

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“…However, these standard unification pictures for the difference between these classes meet challenges after the discovery of 'Changing-look' AGNs or blazars. The shifting between Type I AGNs and Type II AGNs was observed and reported (Matt et al 2003;Bianchi et al 2005;Marchese et al 2012;Shappee et al 2014), and the shifting was also reported between FSRQs and BL Lacs (Isler et al 2013(Isler et al , 2015Mishra et al 2021).…”

Section: Comparing With 'Changing-look' Blazars In Previous Workmentioning

confidence: 54%

“…The classification types, which based on the optical spectrum of AGNs and that of blazars were harmonious until the discovery of 'Changing-look' AGNs (Matt et al 2003;Bianchi et al 2005). The shifting between Type I AGNs and Type II AGNs, or the shifting between FSRQs and BL Lacs has brought great challenges to the AGN unification model (Marchese et al 2012;Shappee et al 2014;Isler et al 2013;Mishra et al 2021;Peña-Herazo et al 2021). There are explanations for the shifting, among them the sudden change of accretion ratio arising the shift seems promising.…”

Section: Introductionmentioning

confidence: 99%

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An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect

Xiao¹,

Jiang²,

Ouyang³

et al. 2022

Preprint

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It is known that the blazar jet emissions are dominated by non-thermal radiation while the accretion disk jets are normally dominated by thermal emission. In this work, our aim is to study the connection between the two types of emission by investigating the correlation between the blazar emission line intensity property, which embodies the nature of accretion disk, and the γ-ray flux property, which is the representative of jet emission. We compiled a sample of 656 blazars with available emission line equivalent widths (EW ), the GeV γ-ray flux, and the SED information from the literature. In this work, we found 55 previous BCUs are now identified as FSRQs, and found 52 'Changing-look' blazars based on their EW and 45 of them are newly confirmed. These 'Changing-look' blazars have a larger accretion ratio ( Ṁ / ṀEdd ) than BL Lac objects. In addition, we suggest that the lower synchrotron peak blazars (LSPs) could be the source of 'Changing-look' blazars because 90.7% of the 'Changinglook' blazars in this work are confirmed as LSPs. An anti-correlation between EW and continuum intensity, the so-called global 'Baldwin effect' (BEff) has been confirmed. We suggest the steeper global BEff observed for blazar than for radio-quiet active galactic nuclei (RQ-AGNs) is caused by the inverse Compton scattering of broad-emission-line photons. This interpretation is further supported by the positive correlation between the emission line EW and intrinsic inverse Compton luminosity.

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Section: Comparing With 'Changing-look' Blazars In Previous Workmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect

Xiao¹,

Jiang²,

Ouyang³

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…How much extend FeII emission region is under debate, but it is likely comparable to the dust sublimation radius (e.g., He et al 2021;Mishra et al 2021;Gaskell et al 2022). The typical sublimation radius is ∼ 100 light days (Namekata & Umemura 2016), but the typical difference in observation epoch in Analysis 3 is ∼ 1, 000 days.…”

Section: Distribution On the Ev1 Planementioning

confidence: 99%

The relation between quasars' optical spectra and variability

Nagoshi¹,

Iwamuro²

2022

Preprint

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Brightness variation is an essential feature of quasars, but its mechanism and relationship to other physical quantities are not understood well. We aimed to find the relationship between the optical variability and spectral features to reveal the regularity behind the random variation. It is known that quasar's FeII/Hβ flux ratio and equivalent width of [OIII]5007 are negatively correlated, called Eigenvector 1. In this work, we visualized the relationship between the position on this Eigenvector 1 (EV1) plane and how they had changed their brightness after ∼ 10 years. We conducted three analyses using different quasar sample each. The first analysis showed the relation between their distributions on the EV1 plane and how much they had changed brightness, using 13,438 Sloan Digital Sky Survey quasars. This result shows how brightness changes later are clearly related to the position on the EV1 plane. In the second analysis, we plotted the sources reported as Changing-Look Quasars (or Changing-State Quasars) on the EV1 plane. This result shows that the position on the EV1 plane corresponds activity level of each source, the bright or dim state of them are distributed on the opposite sides divided by the typical quasar distribution. In the third analysis, we examined the transition vectors on the EV1 plane using sources with multiple-epoch spectra. This result shows that the brightening and dimming sources move on the similar path and they turn into the position corresponding to the opposite activity level. We also found this trend is opposite to the empirical rule that R FeII positively correlated with the Eddington ratio, which has been proposed based on the trends of a large number of quasars. From all these analyses, it is indicated that quasars tend to oscillate between both sides of the distribution ridge on the EV1 plane, each of them corresponds to a dim state and a bright state. This trend in optical variation suggests that significant brightness changes, such as Changing-Look quasars, are expected to repeat.

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“…With the term changing-look AGN (CLAGN), we refer to those sources that can change their classification (e.g., from BLLAC to FSRQ or vice versa) after some dramatic event, such as a change in the accretion or in the jet activity [28][29][30][31][32][33]. Sometimes the jet activity can determine changes in the observational appearance but not a change in classification: for example, the decrease/increase of equivalent width of the emission lines when the continuum increases/decreases because of the jet activity [34][35][36][37] or a shift of the synchrotron peak [38,39].…”

Section: Classificationmentioning

confidence: 99%

A New Sample of Gamma-Ray Emitting Jetted Active Galactic Nuclei—Preliminary Results

et al. 2021

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We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and classifications to be used to calibrate jet power. We searched in the available literature for all the published optical spectra and multiwavelength studies useful to characterize the sources. We found new, missed, or even forgotten information leading to a substantial change in the redshift values and classification of many sources. We present here the preliminary results of this analysis and some statistics based on the gamma-ray sources with right ascension within the interval 0h--12h (J2000). Although flat-spectrum radio quasars and BL Lac objects are still the dominant populations, there is a significant increase in the number of other objects, such as misaligned AGN, narrow-line Seyfert 1 galaxies, and Seyfert galaxies. We also introduced two new classes of objects: changing-look AGN and ambiguous sources. About one third of the sources remain unclassified.

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The Changing-look Blazar B2 1420+32

Cited by 20 publications

References 75 publications

An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect

An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect

The relation between quasars' optical spectra and variability

A New Sample of Gamma-Ray Emitting Jetted Active Galactic Nuclei—Preliminary Results

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