English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The well studied blazar 3C 279 underwent a giant $\gamma$-ray outburst in2014 March-April. The measured $\gamma$-ray flux (1.21 $\pm$ 0.10 $\times$10$^{-5}$ ph cm$^{-2}$ s$^{-1}$ in 0.1-300 GeV energy range) is the highestdetected from 3C 279 by Fermi Large Area Telescope. Hour scale $\gamma$-rayflux variability are observed, with a flux doubling time as short as 1.19 $\pm$0.36 hours detected during one flare. The $\gamma$-ray spectrum is found to becurved at peak of the flare suggesting low probability of detecting very highenergy (VHE; E $>$ 100 GeV) emission, which is further confirmed by the VeryEnergetic Radiation Imaging Telescope Array System observations. The$\gamma$-ray flux increased by more than an order in comparison to low activitystate and the flare consists of multiple sub-structures having fast rise andslow decay profile. The flux enhancement is seen in all the wavebands though ata lesser extent compared to $\gamma$-rays. During the flare, a considerableamount of the kinetic jet power gets converted to $\gamma$-rays and the jetbecomes radiatively efficient. A one zone leptonic emission model is used toreproduce the flare and we find increase in the bulk Lorentz factor as a majorcause of the outburst. From the observed fast variability, lack of VHEdetection, and the curved $\gamma$-ray spectrum, we conclude that the locationof the emission region cannot be far out from the broad line region (BLR) andcontributions from both BLR and torus photons are required to explain theobserved $\gamma$-ray spectrum.

Multi-wavelength observations of 3C 279 during the extremely bright gamma-ray flare in 2014 March-April