Efthalia Traianou
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View article: Spatially resolved polarization swings in the supermassive binary black hole candidate OJ 287 with first Event Horizon Telescope observations
Spatially resolved polarization swings in the supermassive binary black hole candidate OJ 287 with first Event Horizon Telescope observations Open
We present the first Event Horizon Telescope 1.3 mm observations of the supermassive binary black hole candidate OJ 287. The observations achieved an unprecedented angular resolution of 18 μas and reveal significant structural and polariza…
Polarization as a Probe of Neutrino Emission from Blazars Open
The source of extragalactic neutrinos in the TeV–PeV range is a matter of very active research, with blazar jets having been postulated to be the origin of at least some of the detections. The blazar PKS 0735+178 is a prominent example; du…
View article: Unveiling blazar synchrotron emission: a multiwavelength polarimetric study of HSP and LSP populations
Unveiling blazar synchrotron emission: a multiwavelength polarimetric study of HSP and LSP populations Open
Polarimetric properties of blazars allow us to put constraints on the acceleration mechanisms that fuel their powerful jets. By studying the multiwavelength polarimetric behaviour of high synchrotron peaked (HSP) and low synchrotron peaked…
Polarisation as a probe of neutrino emission from blazars Open
The source of extragalactic neutrinos in the TeV-PeV range is a matter of very active research, with blazar jets having been postulated to be the origin of at least some of the detections. The blazar PKS 0735+178 is a prominent example; du…
View article: Revealing a ribbon-like jet in OJ 287 with RadioAstron
Revealing a ribbon-like jet in OJ 287 with RadioAstron Open
We present space-based very long baseline interferometry observations of the BL Lac type object OJ 287 taken with RadioAstron at 22 GHz on April 25, 2016, in conjunction with a ground array comprising 27 radio telescopes. We detect ground-…
View article: High Optical-to-X-Ray Polarization Ratio Reveals Compton Scattering in BL Lacertae’s Jet
High Optical-to-X-Ray Polarization Ratio Reveals Compton Scattering in BL Lacertae’s Jet Open
Blazars, supermassive black hole systems with highly relativistic jets aligned with the line of sight, are the most powerful long-lived emitters of electromagnetic emission in the Universe. We report here on a radio-to-gamma-ray multiwavel…
View article: Gamma-ray flares from the jet of the blazar CTA 102 in 2016–2018
Gamma-ray flares from the jet of the blazar CTA 102 in 2016–2018 Open
CTA 102 is a γ -ray bright blazar that exhibited multiple flares in observations by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope during the period of 2016–2018. We present results from the analysis of multi-wavelen…
Investigating launching of black hole jets with the combined power of the EVN and the EHT Open
AGN-launched jets are a crucial element in the study of supermassive black holes (SMBH) and their closest surroundings. The formation of such jets, whether they are launched by magnetic field lines anchored to the accretion disc or directl…
View article: Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018
Gamma-ray flares from the jet of the blazar CTA 102 in 2016-2018 Open
CTA 102 is a $γ$-ray bright blazar that exhibited multiple flares in observations by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope during the period of 2016-2018. We present results from the analysis of multi-wavele…
View article: A multifrequency study of sub-parsec jets with the Event Horizon Telescope
A multifrequency study of sub-parsec jets with the Event Horizon Telescope Open
Context. The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and r…
View article: A multi-frequency study of sub-parsec jets with the Event Horizon Telescope
A multi-frequency study of sub-parsec jets with the Event Horizon Telescope Open
The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and relativist…
View article: Helical magnetic field structure in 3C 273. A Faraday rotation analysis using multi-frequency polarimetric VLBA data
Helical magnetic field structure in 3C 273. A Faraday rotation analysis using multi-frequency polarimetric VLBA data Open
We present a study on rotation measure (RM) of the quasar 3C 273. This analysis aims to discern the magnetic field structure and its temporal evolution. The quasar 3C 273 is one of the most studied active galactic nuclei due to its high br…
View article: Unveiling the bent-jet structure and polarization of OJ 287 at 1.7 GHz with space VLBI <i>(Corrigendum)</i>
Unveiling the bent-jet structure and polarization of OJ 287 at 1.7 GHz with space VLBI <i>(Corrigendum)</i> Open
Peer reviewed
View article: A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour
A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour Open
Context. Blazars are beamed active galactic nuclei (AGNs) known for their strong multi-wavelength variability on timescales ranging from years down to minutes. Many different models have been proposed to explain this variability. Aims. We …
View article: A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour
A wiggling filamentary jet at the origin of the blazar multi-wavelength behaviour Open
Blazars are beamed active galactic nuclei known for their strong multi-wavelength variability on timescales from years down to minutes. We aim to investigate the suitability of the twisting jet model presented in previous works to explain …
Evidence of a toroidal magnetic field in the core of 3C 84 Open
The spatial scales of relativistic radio jets, probed by relativistic magneto-hydrodynamic (RMHD) jet launching simulations and by most very long baseline interferometry (VLBI) observations differ by an order of magnitude. Bridging the gap…
View article: Ordered magnetic fields around the 3C 84 central black hole
Ordered magnetic fields around the 3C 84 central black hole Open
Context. 3C 84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of very-long-baseline interfero…
Unveiling the bent-jet structure and polarization of OJ 287 at 1.7 GHz with space VLBI Open
We present total intensity and linear polarization images of OJ 287 at 1.68 GHz, obtained through space-based very long baseline interferometry (VLBI) observations with RadioAstron on April 16, 2016. The observations were conducted using a…
View article: Lost in the curve: Investigating the disappearing knots in the blazar 3C 454.3
Lost in the curve: Investigating the disappearing knots in the blazar 3C 454.3 Open
One of the most well-known extragalactic sources in the sky, quasar 3C 454.3, shows a curved parsec-scale jet that has been exhaustively monitored with very-long-baseline interferometry (VLBI) over the recent years. In this work, we presen…
Unveiling the Bent Jet Structure and Polarization of OJ 287 at 1.7 GHz with Space VLBI Open
We present total intensity and linear polarization images of OJ287 at 1.68GHz, obtained through space-based VLBI observations with RadioAstron on April 16, 2016. The observations were conducted using a ground array consisting of the VLBA a…
View article: Lost in the curve: Investigating the disappearing knots in blazar 3C 454.3
Lost in the curve: Investigating the disappearing knots in blazar 3C 454.3 Open
One of the most well-known extragalactic sources in the sky, quasar 3C 454.3 , shows a curved parsec-scale jet that has been exhaustively monitored with very-long-baseline interferometry (VLBI) over the recent years. In this work, we prese…
Repeating flaring activity of the blazar AO 0235+164 Open
Context. Blazar AO 0235+164 , located at a redshift of z = 0.94, has undergone several sharp multi-spectral-range flaring episodes over recent decades. In particular, the episodes that peaked in 2008 and 2015, which were subject to extensi…
The Repeating Flaring Activity of Blazar AO 0235+164 Open
Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive multi-wavel…
View article: A Near Magnetic-to-kinetic Energy Equipartition Flare from the Relativistic Jet in AO 0235+164 during 2013-2019
A Near Magnetic-to-kinetic Energy Equipartition Flare from the Relativistic Jet in AO 0235+164 during 2013-2019 Open
We present the multiwavelength flaring activity of the blazar AO 0235+164 during its recent active period from 2013 to 2019. From a discrete correlation function (DCF) analysis, we find a significant (>95%) correlation between radio and $γ…
View article: A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019
A near magnetic-to-kinetic energy equipartition flare from the relativistic jet in AO 0235 + 164 during 2013–2019 Open
We present the multiwavelength flaring activity of the blazar AO 0235 + 164 during its recent active period from 2013 to 2019. From a discrete correlation function analysis, we find a significant ($\gt 95~{{\ \rm per\ cent}}$) correlation …
View article: Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics
Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics Open
In the past few years, the Event Horizon Telescope (EHT) has provided the first-ever event horizon-scale images of the supermassive black holes (BHs) M87* and Sagittarius A* (Sgr A*). The next-generation EHT project is an extension of the …
View article: The Event Horizon Telescope Image of the Quasar NRAO 530
The Event Horizon Telescope Image of the Quasar NRAO 530 Open
We report on the observations of the quasar NRAO 530 with the Event Horizon Telescope (EHT) on 2017 April 5−7, when NRAO 530 was used as a calibrator for the EHT observations of Sagittarius A*. At z = 0.902, this is the most distant object…
Multi-Wavelength and Multi-Messenger Studies Using the Next-Generation Event Horizon Telescope Open
The next-generation Event Horizon Telescope (ngEHT) will provide us with the best opportunity to investigate supermassive black holes (SMBHs) at the highest possible resolution and sensitivity. With respect to the existing Event Horizon Te…
Multi-Wavelength and Multi-Messenger Studies with the next-generation Event Horizon Telescope Open
The next-generation Event Horizon Telescope (ngEHT) will provide us with the best opportunity to investigate supermassive black holes (SMBHs) at the highest possible resolution and sensitivity. With respect to the existing Event Horizon Te…