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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present the results of a broadband radio-to-GeV observing campaignorganized to get a better understanding of the radiation processes responsiblefor the $\gamma$-ray flares observed in 3C 279. The total intensity andpolarization observations of the source were carried out between December 28,2013 and January 03, 2014 using the Fermi-LAT, Swift-XRT, Swift-UVOT, and KVNtelescopes. A prominent flare observed in the optical/near-UV passbands wasfound to be correlated with a concurrent $\gamma$-ray flare at a confidencelevel $>$95$\%$, which suggests a co-spatial origin of the two. Moreover, theflaring activity in the two regimes was accompanied by no significant spectralvariations. A peak in the X-ray light curve coincides with the peaks of thefractional polarization curves at 43 and 86 GHz radio bands. No prominentvariation was noticed for the total intensity and the electric vector positionangle (EVPA) observations at radio bands during this period. We noticed apossible hint of steepening of the radio spectrum with an increase inpercentage polarization, which suggests that the radio polarization variationscould be simply due to a spectral change. In a simple scenario, the correlatedoptical/$\gamma$-ray flares could be caused by the same population of emittingparticles. The coincidence of the increase in radio polarization with the X-rayflux supports the picture that X-rays are produced via inverse-Comptonscattering of radio photons. The observed fractional variability for the$\gamma$-ray flare $\sim$0.23 does not exceed that in the optical regime, whichis inconsistent with what we usually observe for 3C 279; it could be due todifferent dependencies of the magnetic field and the external radiation fieldenergy density profiles along the jet.

Probing the gamma-ray variability in 3C279 using broadband observations