  We show that the observed pulsed optical emission of the anomalous X-ray
pulsar 4U 0142+61 can be accounted for by both the magnetar outer gap models
and the disk-star dynamo gap models, therefore is not an evidence in favor of
one of these models as its responsible mechanism. Nevertheless, the estimated
high energy gamma-ray spectra from these models have different power-low
indices, and can be tested by future observations of the Gamma-ray Large-Area
Space Telescope (GLAST). Furthermore, we show by analytical estimations that
the expectations of a standard disk model is in agreement with the observed
unpulsed optical and infrared luminosities of the AXP 4U 0142+61.

Astrophysics