We report the discovery of 44.7 ms pulsations from the X-ray source CXOU J181335.1 - 174957 using data obtained with the XMM-Newton Observatory .
PSR J1813 - 1749 lies near the center of the young radio supernova remnant G12.82 - 0.02 , which overlaps the compact TeV source HESS J1813 - 178 .
This rotation-powered pulsar is the second most energetic in the Galaxy , with a spin-down luminosity of \dot { E } = ( 6.8 \pm 2.7 ) \times 10 ^ { 37 } erg s ^ { -1 } .
In the rotating dipole model , the surface dipole magnetic field strength is B _ { s } = ( 2.7 \pm 0.6 ) \times 10 ^ { 12 } G and the spin-down age \tau _ { c } \equiv P / 2 \dot { P } = 3.3 - 7.5 kyr , consistent with the location in the small , shell-type radio remnant .
At an assumed distance of 4.7 kpc by association with an adjacent young stellar cluster , the efficiency of PSR J1813 - 1749 in converting spin-down luminosity to radiation is \approx 0.03 \% for its 2 - 10 keV flux , \approx 0.1 \% for its 20 - 100 keV INTEGRAL flux , and \approx 0.07 \% for the > 200 GeV emission of HESS J1813 - 178 , making it a likely power source for the latter .
The nearby young stellar cluster is possibly the birthplace of the pulsar progenitor , as well as an additional source of seed photons for inverse Compton scattering to TeV energies .