Study on temporal and spectral behaviour of 3C 279 during 2018 January flare

Shah, Zahir; Jithesh, V.; Sahayanathan, S.; Misra, Ranjeev; Iqbal, Naseer

doi:10.1093/mnras/stz151

Cited by 27 publications

(27 citation statements)

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“…Here, θ j is the jet opening angle, and it is related to jet Lorentz factor through the relation θ j Γ j ~ 0.2 as suggested 38 . Thus, we conclude that the gamma-ray flare region lies outside of the BLR in 3C 279 in agreement with other recent studies 26 , 32 , 39 – 41 . Figure 2 b shows a schematic diagram of the envisaged scenario: The minute-scale-flares superimposed on the more slowly varying envelope emission result from the magnetic reconnection of multiple twisted flux ropes in a turbulent, filamentary region where the magnetically dominated jet becomes unstable to the kink instability.…”

Section: Discussionsupporting

confidence: 93%

Gamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279

Shukla

Mannheim

2020

Nat Commun

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Spinning black holes in the centres of galaxies can release powerful magnetised jets. When the jets are observed at angles of less than a few degrees to the line-of-sight, they are called blazars, showing variable non-thermal emission across the electromagnetic spectrum from radio waves to gamma rays. It is commonly believed that shock waves are responsible for this dissipation of jet energy. Here we show that gamma-ray observations of the blazar 3C 279 with the space-borne telescope Fermi-LAT reveal a characteristic peak-in-peak variability pattern on time scales of minutes expected if the particle acceleration is instead due to relativistic magnetic reconnection. The absence of gamma-ray pair attenuation shows that particle acceleration takes place at a distance of ten thousand gravitational radii from the black hole where the fluid dynamical kink instability drives plasma turbulence.

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Section: Discussionsupporting

confidence: 93%

Gamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279

Shukla

Mannheim

2020

Nat Commun

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“…The model parameter space obtained in the present study is broadly consistent with the previous values in the literature (Sahayanathan et al 2018;Hayashida et al 2015;Sahayanathan & Godambe 2012). Recently, Shah et al (2019) have studied the flaring episode of 3C 279 observed in January 2018 and report that the increase in the value of Γ causes flux enhancement during the outburst.…”

Section: Spectral Energy Distribution Modellingsupporting

confidence: 90%

Understanding the giant gamma-ray outburst on June 16, 2015 from the blazar 3C 279

Singh

Meintjes

Ramamonjisoa

2020

Astrophys Space Sci

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A very bright and fast varying gamma-ray flare has been detected from the blazar 3C 279 on June 16, 2015. We have studied the broadband spectral energy distribution of the source during the flaring episode and in the low activity state using a simple one zone leptonic model. We find that an electron energy distribution described by a broken power law can be used to reproduce the broadband emissions during the high and low activity states. The flux measurements at radio, infrared and optical frequencies are reproduced by the synchrotron emission resulting from the relativistic electrons in a jet magnetic field strength of 0.37 G. The gamma-ray emission from the blazar 3C 279 is attributed to the Comptonization of the IR seed photons from the dusty torus with a temperature of 870 K. The outburst from the source observed on June 16, 2015 can be ascribed to an efficient acceleration process associated with a sudden enhancement in the electron energy density in the emitting region with respect to the low activity state. The fast gamma-ray variability at a minute timescale implies that the emission during the flare originates from a more compact region and the size of the emission zone in the low activity state is found to be four times larger than that during the flare. We have also used the model parameters derived from the broadband spectral energy distribution modelling to investigate a few physical properties of the jet during the outburst.

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“…The best fit results suggest that there is no significant variation in the bulk Lorentz factor Γ during different flux states. However, it can be noted that the obtained Γ values are lesser compared to the typical value as observed in other FSRQs (Shah et al 2017(Shah et al , 2019. Since the source parameters obtained through the spectral fit depend on the equipartition condition and other frozen quantities, relaxing these assumptions can result in larger Γ.…”

Section: Summary and Discussionmentioning

confidence: 73%

“…The Spearman's rank correlation coefficient (r) and the correlation probability (P) have been found as -0.07 and 0.66 for the correlation between F0.1−300GeV and α, -0.33 and 0.33 between F0.1−300GeV and β during F1 state; while for F2 state, the r and P values are 0.10 and 0.39 for correlation between F0.1−300GeV and α, and -0.24 and 0.04 between F0.1−300GeV and β, respectively. The obtained results suggest that there is no correlation between these parameters or no 'harder when brighter' trend is observed for the source, which is witnessed in most of the blazars (Shah et al 2019;Khatoon et al 2020;Prince 2020). However, recently Prince et al 2021 found that the FSRQ OQ 334 has also not shown spectral hardening behavior with 12 hr binned gamma-ray flux.…”

Section: Spectral Variationmentioning

confidence: 82%

Temporal and spectral study of PKS 0208-512 during 2019-20 flare

Khatoon,

Prince,

Shah

et al. 2021

Preprint

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We present the temporal and spectral study of blazar PKS 0208-512, using recent flaring activity from November 2019 to March 2020, as detected by Fermi-LAT, Swift-XRT/UVOT observatories. The source was in a low γ-ray flux state for a decade and started flaring in November 2019, which continues until March 2020. During the activity state, 2-days binned γ-ray lightcurve shows multiple-peaks indicating sub-flares. To understand the possible physical mechanisms behind flux enhancement, a detailed temporal and spectral study has been carried out by dividing the activity into several flux-states. Timing analysis of lightcurves suggests that peaks of sub-flares have rise and decay time in days-order with flux-doubling time ∼ 2-days. The 2-days binned γ-ray lightcurve shows double-lognormal flux distribution. The broadband spectral energy distribution for three selected flux states can be well fitted under synchrotron, synchrotron-self-Compton (SSC) and external-Compton (EC) emission mechanisms. We obtained the physical parameters of the source and their confidence intervals through χ 2 -statistics. Our spectral study suggests that during quiescent-state, gamma-ray spectrum can be well explained by considering the EC-scattering of IR-photons from the dusty-torus. However, gamma-ray spectra corresponding to flares demand additional target photons from broad-line-region (BLR) along with the IR. These suggest that during flares, the emission-region is close to the edge of BLR, while for quiescent-state the emission-region is away from the BLR. The best-fit results suggest that, marginal increase in the magnetic-field can result in the flux enhancement. This is possibly associated with the efficiency of particle acceleration during flaring-states as compared to quiescent-state.

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Study on temporal and spectral behaviour of 3C 279 during 2018 January flare

Cited by 27 publications

References 50 publications

Gamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279

Gamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279

Understanding the giant gamma-ray outburst on June 16, 2015 from the blazar 3C 279

Temporal and spectral study of PKS 0208-512 during 2019-20 flare

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