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

We present results from daily monitoring of gamma rays in the energy range$\sim0.5$ to $\sim100$ TeV with the first 17 months of data from the HighAltitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2steradians and duty cycle of $>95$% are unique features compared to other TeVobservatories that allow us to observe every source that transits over HAWC forup to $\sim6$ hours each sidereal day. This regular sampling yieldsunprecedented light curves from unbiased measurements that are independent ofseasons or weather conditions. For the Crab Nebula as a reference source wefind no variability in the TeV band. Our main focus is the study of the TeVblazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields apower law index $\Gamma=2.21 \pm0.14_{\mathrm{stat}}\pm0.20_{\mathrm{sys}}$ andan exponential cut-off $E_0=5.4 \pm 1.1_{\mathrm{stat}}\pm 1.0_{\mathrm{sys}}$TeV. For Mrk 501, we find an index $\Gamma=1.60\pm 0.30_{\mathrm{stat}} \pm0.20_{\mathrm{sys}}$ and exponential cut-off $E_0=5.7\pm 1.6_{\mathrm{stat}}\pm 1.0_{\mathrm{sys}}$ TeV. The light curves for both sources show clearvariability and a Bayesian analysis is applied to identify changes between fluxstates. The highest per-transit fluxes observed from Mrk 421 exceed the CrabNebula flux by a factor of approximately five. For Mrk 501, several transitsshow fluxes in excess of three times the Crab Nebula flux. In a comparison tolower energy gamma-ray and X-ray monitoring data with comparable sampling wecannot identify clear counterparts for the most significant flaring featuresobserved by HAWC.

Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC