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

Mrk 421 and Mrk 501 are two close, bright and well-studiedhigh-synchrotron-peaked blazars, which feature bright and persistent GeV andTeV emission. We use the longest and densest dataset of unbiased observationsof these two sources, obtained at TeV and GeV energies during five years withFACT and Fermi-LAT. To characterize the variability and derive constraints onthe emission mechanism, we augment the dataset with contemporaneousmulti-wavelength observations from radio to X-rays. We correlate the lightcurves, identify individual flares in TeV energies and X-rays, and look forinter-band connections, which are expected from the shock propagations withinthe jet. For Mrk 421, we find that the X-rays and TeV energies are wellcorrelated with close to zero lag, supporting the SSC emission scenario. Thetiming between the TeV, X-ray flares in Mrk 421 is consistent with periodsexpected in the case of Lense-Thirring precession of the accretion disc. Thevariability of Mrk 501 on long-term periods is also consistent with SSC, with asub-day lag between X-rays and TeV energies. Fractional variability for bothblazars shows a two bump structure with the highest variability in the X-rayand TeV bands.

Relentless multi-wavelength variability of Mrk 421 and Mrk 501