| Resumen |
We present results from daily monitoring of gamma-rays in the energy range from ∼0.5 to ∼100 TeV with the first
17 months of data from the High Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2
steradians and duty cycle of >95% are unique features compared to other TeV observatories that allow us to
observe every source that transits over HAWC for up to ∼6 hr each sidereal day. This regular sampling yields
unprecedented light curves from unbiased measurements that are independent of seasons or weather conditions.
For the Crab Nebula as a reference source, we find no variability in the TeV band. Our main focus is the study of
the TeV blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a power-law index
G = 2.21 0.14 0.20 stat sys and an exponential cut-off E0 stat sys = 5.4 1.1 1.0 TeV. For Mrk 501, we find
an index G = 1.60 0.30 0.20 stat sys and exponential cut-off E0 stat sys = 5.7 1.6 1.0 TeV. The light curves
for both sources show clear variability and a Bayesian analysis is applied to identify changes between flux states.
The highest per-transit fluxes observed from Mrk 421 exceed the Crab Nebula flux by a factor of approximately
five. For Mrk 501, several transits show fluxes in excess of three times the Crab Nebula flux. In a comparison to
lower energy gamma-ray and X-ray monitoring data with comparable sampling, we cannot identify clear
counterparts for the most significant flaring features observed by HAWC. |
