The Quasar CTD 135 is Not a Compact Symmetric Object

Abstract

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 gamma-rays, while the vast majority of known gamma-ray emitting AGN are blazars with jets pointing close to our viewing direction. Since only a handful of CSOs are known as gamma-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

arXiv comment12 pages, 4 figures, accepted for publication in the open-access journal Symmetry (special issue Astronomy and Symmetry)

References in corpus (33)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Unified Schemes for Radio-Loud Active Galactic Nuclei
• Fermi Large Area Telescope Fourth Source Catalog
• Initial Performance of the NEOWISE Reactivation Mission
• The third realization of the International Celestial Reference Frame by very long baseline interferometry
• MOJAVE: XV. VLBA 15 GHz Total Intensity and Polarization Maps of 437 Parsec-Scale AGN Jets From 1996-2017
• Compact steep-spectrum and peaked-spectrum radio sources
• MOJAVE XIII. Parsec-Scale AGN Jet Kinematics Analysis Based on 19 years of VLBA Observations at 15 GHz
• Spectroscopy of Broad Line Blazars from 1LAC
• The Dynamic Evolution of Young Extragalactic Radio Sources
• Identification of the infrared non-thermal emission in Blazars
• On the Evolution of and High-Energy Emission from GHz-Peaked-Spectrum Sources
• MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies
• VLBI-Gaia offsets favor parsec-scale jet direction in Active Galactic Nuclei
• Kinematic Age Estimates for 4 Compact Symmetric Objects from the Pearson-Readhead Survey
• Two new catalogs of blazar candidates in the WISE infrared sky
• Rapid Infrared Variability of Three Radio-loud Narrow-line Seyfert 1 Galaxies: A View from the Wide-field Infrared Survey Explorer
• First detection in gamma-rays of a young radio galaxy: Fermi-LAT observations of the Compact Symmetric Object PKS 1718-649
• Jet Emission in Young Radio Sources: a Fermi-LAT Gamma-ray View
• Radio Follow-up on all Unassociated Gamma-ray Sources from the Third Fermi Large Area Telescope Source Catalog
• MOJAVE XVI: Multi-Epoch Linear Polarization Properties of Parsec-Scale AGN Jet Cores
• NGC 3894: a young radio galaxy seen by Fermi-LAT
• New prediction of extragalactic GeV gamma-ray emission from radio lobes of young AGN jets
• Compact Bright Radio-loud AGNs -- III. A Large VLBA Survey at 43 GHz
• VIMAP: an Interactive Program Providing Radio Spectral Index Maps of Active Galactic Nuclei
• Parsec-scale jet properties of the gamma-ray quasar 3C 286
• Mid-infrared Variability of gamma-ray emitting blazars
• Radio Properties of the $\gamma$-ray Emitting CSO Candidate 2234+282
• Comparison of multifrequency positions of extragalactic sources from global geodetic VLBI monitoring program and Gaia EDR3
• Highly Variable $\gamma$-Ray Emission of CTD 135 and Implications for its Compact Symmetric Structure
• What defines a compact symmetric object? A carefully vetted sample of CSOs
• The Fermi-LAT view of young radio sources
• J1110+4817 -- a compact symmetric object candidate revisited