Two Flares with One Shock: The Interesting Case of 3C 454.3

Liodakis, Ioannis; Blinov, D.; Jorstad, Svetlana G.; Архаров, А. А.; Paola, Andrea; Ефимова, Н. В.; Grishina, T. S.; Kiehlmann, S.; Kopatskaya, E. N.; Larionov, V. M.; Ларионова, Л. В.; Ларионова, Е. Г.; Marscher, A. P.; Morozova, D. A.; Nikiforova, A. A.; Pavlidou, V.; Traianou, Efthalia; Troitskaya, Yu. V.; Troitsky, I. S.; Uemura, Makoto; Weaver, Z. R.

doi:10.3847/1538-4357/abb1b8

Cited by 32 publications

(21 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the peak of the optical flare abrupt rotation of ∼ 206 degrees was observed that happened in about three days . Similar rotation of the PA was also reported by Liodakis et al (2020). In epoch C, an abrupt change of 138 degrees within a day was also observed in the PA.…”

Section: C 4543supporting

confidence: 87%

Correlation between optical flux and polarization variations in Flat Spectrum Radio Quasars on diverse timescales

Pandey,

Rajput,

Stalin

2021

Preprint

View full text Add to dashboard Cite

Study of the polarization behaviour in blazars is a powerful tool to discern the role of magnetic field in the variable emission process in their relativistic jets. We present here results of our systematic investigation on the correlation between optical flux and polarization variations for eight flat spectrum radio quasars on various timescales using data from the Steward Observatory that covers a period of ∼10 years. On long time scales (∼several months), from a total of 79 observing cycles, in 34 observing cycles, we found a significant positive correlation between optical flux and optical polarization degree (PD), negative correlation in 3 cycles and no correlation in 42 cycles. On short time scales (∼few days), in 47 out of a total of 55 epochs, we found a positive correlation between optical flux and PD, while, on the remaining 8 epochs, an anti-correlation was detected between the two quantities. Moreover, we noticed a significant positive correlation between optical and 𝛾−ray fluxes on 14 epochs and a negative correlation between the two on one epoch. While the observed optical flux changes well fit in the shock-in-jet model, the observed changes in PD are not explainable by changes in the power-law spectral index of the relativistic electrons in the jet. Instead, the observed varied correlations between optical flux and PD could be due to multi-zone emission regions or the enhanced flux coinciding with the emergence of a new emission knot with its magnetic field either aligned or misaligned with the large scale magnetic field.

show abstract

Section: C 4543supporting

confidence: 87%

Correlation between optical flux and polarization variations in Flat Spectrum Radio Quasars on diverse timescales

Pandey,

Rajput,

Stalin

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…We note that the variability of the polarization fraction and electric vector polarization angle (EVPA) is more pronounced than that of the optical flux. This may be due the effect of turbulence (Marscher, 2014;Liodakis et al, 2020). More data are needed to draw detailed inference about the polarization variability.…”

Section: Discussionmentioning

confidence: 99%

Short-Timescale Variability of the Blazar Mrk 421 from AstroSat and Simultaneous Multi-Wavelength Observations

Chatterjee

Das

Khasnovis

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

We study the multi-wavelength variability of the blazar Mrk 421 at minutes to days timescales using simultaneous data at γ-rays from Fermi, 0.7−20 keV energies from AstroSat, and optical and near infrared (NIR) wavelengths from ground based observatories. We compute the shortest variability timescales at all of the above wave bands and find its value to be ∼1.1 ks at the hard X-ray energies and increasingly longer at soft X-rays, optical and NIR wavelengths as well as at the GeV energies. We estimate the value of the magnetic field to be 0.5 Gauss and the maximum Lorentz factor of the emitting electrons ∼1.6 × 10 5 assuming that synchrotron radiation cooling drives the shortest variability timescale. Blazars vary at a large range of timescales often from minutes to years. These results, as obtained here from the very short end of the range of variability timescales of blazars, are a confirmation of the leptonic scenario and in particular the synchrotron origin of the X-ray emission from Mrk 421 by relativistic electrons of Lorentz factor as high as 10 5 . This particular mode of confirmation has been possible using minutes to days timescale variability data obtained from AstroSat and simultaneous multiwavelength observations.

show abstract

“…Section 3 shows that even daily observations -as in the case of RoboPol season 4 -are not sufficient to avoid the 180 • ambiguity in the fastest varying sources. Liodakis et al (2020) recently reported an EVPA rotation of 230 • in 2 days in 3C 454.3. If the measured rotation correctly represents the intrinsic EVPA progression, the rotation rate exceeds the rate of the fastest rotation detected in the RoboPol data by a factor of 2.…”

Section: Discussionmentioning

confidence: 99%

“…If the measured rotation correctly represents the intrinsic EVPA progression, the rotation rate exceeds the rate of the fastest rotation detected in the RoboPol data by a factor of 2. The data used by Liodakis et al (2020) included RoboPol and other instruments. Multiple instruments gave a cadence faster than 1 day, as is clearly required to measure such fast variability.…”

Section: Discussionmentioning

confidence: 99%

The time-dependent distribution of optical polarization angle changes in blazars

Kiehlmann

Blinov

Liodakis

et al. 2021

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

At optical wavelengths, blazar Electric Vector Position Angle (EVPA) rotations linked with gamma-ray activity have been the subject of intense interest and systematic investigation for over a decade. One difficulty in the interpretation of EVPA rotations is the inherent 180○ ambiguity in the measurements. It is therefore essential, when studying EVPA rotations, to ensure that the typical time-interval between successive observations – i.e. the cadence – is short enough to ensure that the correct modulo 180○ value is selected. This optimal cadence depends on the maximum intrinsic EVPA rotation speed in blazars, which is currently not known. In this paper we address the following questions for the RoboPol sample: What range of rotation speeds for rotations greater than 90○ can we expect? What observation cadence is required to detect such rotations? Have rapid rotations been missed in EVPA rotation studies thus far? What fraction of data is affected by the ambiguity? And how likely are detected rotations affected by the ambiguity? We answer these questions with three seasons of optical polarimetric observations of a statistical sample of blazars sampled weekly with the RoboPol instrument and an additional season with daily observations. We model the distribution of EVPA changes on time scales from 1–30 days and estimate the fraction of changes exceeding 90○. We show that at least daily observations are necessary to measure $>96\%$ of optical EVPA variability in the RoboPol sample of blazars correctly and that intra-day observations are needed to measure the fastest rotations that have been seen thus far.

show abstract

Two Flares with One Shock: The Interesting Case of 3C 454.3

Abstract: OpenBU http://open.bu.edu Astronomy BU Open Access Articles Two flares with one shock: the interesting case of 3C 454.3

Cited by 32 publications

References 79 publications

Correlation between optical flux and polarization variations in Flat Spectrum Radio Quasars on diverse timescales

Correlation between optical flux and polarization variations in Flat Spectrum Radio Quasars on diverse timescales

Short-Timescale Variability of the Blazar Mrk 421 from AstroSat and Simultaneous Multi-Wavelength Observations

The time-dependent distribution of optical polarization angle changes in blazars

Contact Info

Product

Resources

About