We report the detection of a new TeV gamma-ray source , VER J0521+211 ( catalog VER~J0521+211 ) , based on observations made with the VERITAS imaging atmospheric Cherenkov telescope array .
These observations were motivated by the discovery of a cluster of > 30 \mathrm { GeV } photons in the first year of Fermi -LAT observations .
VER J0521+211 is relatively bright at TeV energies , with a mean photon flux of ( 1.93 \pm 0.13 _ { \mathrm { stat } } \pm 0.78 _ { \mathrm { sys } } ) \times 10 ^ { -11 } \mathrm { % cm ^ { -2 } } \mathrm { s ^ { -1 } } above 0.2 \mathrm { TeV } during the period of the VERITAS observations .
The source is strongly variable on a daily timescale across all wavebands , from optical to TeV , with a peak flux corresponding to \sim 0.3 times the steady Crab Nebula flux at TeV energies .
Follow-up observations in the optical and X-ray bands classify the newly-discovered TeV source as a BL Lac-type blazar with uncertain redshift , although recent measurements suggest z = 0.108 .
VER J0521+211 exhibits all the defining properties of blazars in radio , optical , X-ray , and gamma-ray wavelengths .