Mid-infrared variability of γ-ray emitting blazars

Anjum, Ayesha; Stalin, C. S.; Rakshit, Suvendu; Gudennavar, S. B.; Durgapal, Alok

doi:10.1093/mnras/staa771

Cited by 7 publications

(8 citation statements)

References 77 publications

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“…With one exception (J1413+0257), all sources in our sample have sufficient detections in NEOWISE to allow the construction of a light curve. None of the sources in our sample display the erratic and large-amplitude variability that blazars (or flat-spectrum radio quasars) typically display at mid-IR wavelengths (Anjum et al 2020).…”

Section: Blazar Contaminationmentioning

confidence: 77%

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

Nyland

Dong

Patil

et al. 2020

ApJ

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We have performed a search over 3440 deg 2 of Epoch 1 (2017-2019) of the Very Large Array Sky Survey to identify unobscured quasars in the optical (0.2<z<3.2) and obscured active galactic nuclei (AGNs) in the infrared that have brightened dramatically in the radio over the past one to two decades. These sources would have been previously classified as "radio-quiet" quasars based on upper limits from the Faint Images of the Radio Sky at Twenty cm survey (1993-2011), but they are now consistent with "radio-loud" quasars ( -= -L 10 erg s 3 GHz 40 42 1). A quasi-simultaneous, multiband (∼1-18 GHz) follow-up study of 14 sources with the VLA has revealed compact sources (<0 1 or <1 kpc) with peaked radio spectral shapes. The highamplitude variability over decadal timescales at 1.5 GHz (100% to >2500%) but roughly steady fluxes over a few months at 3 GHz are inconsistent with extrinsic variability due to propagation effects, thus favoring an intrinsic origin. We conclude that our sources are powerful quasars hosting compact/young jets. This challenges the generally accepted idea that "radio-loudness" is a property of the quasar/AGN population that remains fixed on human timescales. Our study suggests that frequent episodes of short-lived AGN jets that do not necessarily grow to large scales may be common at high redshift. We speculate that intermittent but powerful jets on subgalactic scales could interact with the interstellar medium, possibly driving feedback capable of influencing galaxy evolution.

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Section: Blazar Contaminationmentioning

confidence: 77%

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

Nyland

Dong

Patil

et al. 2020

ApJ

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“…With one exception (J1413+0257), all sources in our sample have sufficient detections in NEO-WISE to allow the construction of a light curve. None of the sources in our sample display the erratic and large-amplitude variability that blazars (or flat-spectrum radio quasars) typically display at mid-IR wavelengths (Anjum et al 2020).…”

Section: Blazar Contaminationmentioning

confidence: 77%

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

Nyland,

Dong,

Patil

et al. 2020

Preprint

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We have performed a search over 3440 deg 2 of Epoch 1 (2017-2019) of the Very Large Array Sky Survey to identify unobscured quasars in the optical (0.2 < z < 3.2) and obscured active galactic nuclei (AGN) in the infrared that have brightened dramatically in the radio over the past one to two decades. These sources would have been previously classified as "radio-quiet" quasars based on upper limits from the Faint Images of the Radio Sky at Twenty Centimeters survey (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011), but they are now consistent with "radio-loud" quasars (L 3 GHz = 10 40−42 erg s −1 ). A quasi-simultaneous, multiband (∼ 1 − 18 GHz) follow-up study of 14 sources with the VLA has revealed compact sources (< 0.1 or <1 kpc) with peaked radio spectral shapes. The highamplitude variability over decadal timescales at 1.5 GHz (100% to >2500%), but roughly steady fluxes over a few months at 3 GHz, are inconsistent with extrinsic variability due to propagation effects, thus favoring an intrinsic origin. We conclude that our sources are powerful quasars hosting compact/young jets. This challenges the generally accepted idea that "radio-loudness" is a property of the quasar/AGN population that remains fixed on human timescales. Our study suggests that frequent episodes of short-lived AGN jets that do not necessarily grow to large scales may be common at high redshift. We speculate that intermittent but powerful jets on

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“…A coherent outburst lasting for ∼0.5 d in the observed frame (Figure 4), if corrected for the cosmological time dilation, implies an emission region within 0.5/(1 + z) light days, or ∼0.0002 pc. A statistical study of the short-term infrared variability of Fermi-detected blazars by [37] clearly showed the jet origin of their infrared emission observed in the WISE bands.…”

Section: Infrared Colours and Variabilitymentioning

confidence: 98%

The Quasar CTD 135 Is Not a Compact Symmetric Object

Frey

Gabányi

2022

Symmetry

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The radio-loud quasar CTD 135 (2234+282, J2236+2828) has been proposed as a candidate compact symmetric object (CSO), based on its symmetric radio structure revealed by multi-frequency very long baseline interferometry (VLBI) imaging observations on milliarcsec angular scales. CSOs are known as young jetted active galactic nuclei (AGN) whose relativistic plasma jets are misaligned with respect to the line of sight. The peculiarity of CTD 135 as a CSO candidate was its detection in γ-rays, while the vast majority of known γ-ray emitting AGN are blazars with jets pointing close to our viewing direction. Since only a handful of CSOs are known as γ-ray sources, the unambiguous identification of a single candidate is important for studying this rare class of objects. By collecting and interpreting observational data from the recent literature, we revisit the classification of CTD 135. We present evidence that the object, based on its flat-spectrum radio core with high brightness temperature, variability at multiple wavebands, and infrared colours should be classified as a blazar rather than a CSO.

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Mid-infrared variability of γ-ray emitting blazars

Cited by 7 publications

References 77 publications

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST

The Quasar CTD 135 Is Not a Compact Symmetric Object

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