Context : Rapidly oscillating Ap ( roAp ) stars represent a subclass of magnetic , chemically peculiar stars .
The explanation for their pulsations includes suppressed convection due to the strong magnetic field .
These stars rotate slowly such that a solar-like dynamo and ensuing magnetic activity is unlikely to be present .
On the other hand , magnetic activity could provide the particle acceleration suspected to be responsible for the presence of short-lived radionuclides on some roAp stars .

Aims : The detection of X-ray emission from Ap stars can be an indicator for the presence of magnetic activity and dynamo action , provided different origins for the emission , such as wind shocks and close late-type companions , can be excluded .
Here we report on results for \gamma Equ , the only roAp star for which an X-ray detection is reported in ROSAT catalogs .

Methods : We use high resolution imaging in X-rays with Chandra and in the near-infrared with NACO/VLT that allow us to spatially resolve companions down to \leq 1 ^ { \prime \prime } and \sim 0.06 ^ { \prime \prime } separations , respectively .

Results : The bulk of the X-ray emission is associated with a companion of \gamma Equ identified in our NACO image .
Assuming coevality with the primary roAp star ( \sim 900 Myr ) , the available photometry for the companion points at a K-type star with \sim 0.6 M _ { \odot } .
Its X-ray properties are in agreement with the predictions for its age and mass .
An excess of photons with respect to the expected background and contribution from the nearby companion is observed near the optical position of \gamma Equ .
We estimate an X-ray luminosity of \log { L _ { x } } { [ erg / s ] } = 26.6 and \log { ( L _ { x } / L _ { bol } ) } = -7.9 for this emission .
A small offset between the optical and the X-ray image leaves some doubt on its association with the roAp star .

Conclusions : The faint X-ray emission that we tentatively ascribe to the roAp star is difficult to explain as a solar-like stellar corona due to its very low L _ { x } / L _ { bol } level and the very long rotation period of \gamma Equ .
It could be produced in magnetically confined wind shocks implying a mass loss rate of \sim 10 ^ { -14 } M _ { \odot } { / yr } or from an additional unknown late-type companion at separation \leq 0.4 ^ { \prime \prime } .
If confirmed by future deeper X-ray observations this emission could point at the origin for the presence of radioactive elements on some roAp stars .