The eclipsing brown-dwarf binary system 2MASS J05352184-0546085 is a case sui generis .
For the first time , it allows a detailed analysis of the individual properties of young brown dwarfs , in particular , masses , and radii , and the temperature ratio of the system components can be determined accurately .
The system shows a “ temperature reversal ” with the more massive component being the cooler one , and both components are found to be active .
We analyze X-ray images obtained by Chandra and XMM- Newton containing 2MASS J05352184-0546085 in their respective field of view .
The Chandra observatory data show a clear X-ray source at the position of 2MASS J05352184-0546085 , whereas the XMM- Newton data suffer from contamination from other nearby sources , but are consistent with the Chandra detection .
No indications of flaring activity are found in either of the observations ( together \approx 70 ks ) , and we thus attribute the observed flux to quiescent emission .
With an X-ray luminosity of 3 \times 10 ^ { 28 } erg/s we find an L _ { X } / L _ { bol } -ratio close to the saturation limit of 10 ^ { -3 } and an L _ { X } / L _ { H \alpha } -ratio consistent with values obtained from low-mass stars .
The X-ray detection of 2MASS J05352184-0546085 reported here provides additional support for the interpretation of the temperature reversal in terms of magnetically suppressed convection , and suggests that the activity phenomena of young brown dwarfs resemble those of their more massive counterparts .