A BeppoSAX observation of the z=2.34 quasar PKS2149 - 306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV , 150 keV in the quasar frame .
The Beppo-SAX spectrum spans almost 3 decades ( 0.3 - 150 keV , quasar frame ) and shows an extremely hard ( \alpha =0.4 \pm 0.05 ) X-ray spectrum above 3 keV ( comparable to XJB the X-ray background slope ) , and either a softer ( \alpha =1.0 ^ { +0.6 } _ { -0.3 } ) low energy component , or an ionized absorber at zero redshift .
No evidence is seen of an Fe-K emission line ( EW < 167 eV at 6.5 keV quasar frame ) , a Compton hump ( R < 0.3 ) .
A bremsstrahlung fit gives kT ( rest ) =46 ^ { +32 } _ { -16 } keV , similar to the X-ray background value , and a high energy cut-off power law requires E _ { cut } > 120 keV ( quasar frame ) .

The SED of PKS 2149 - 306 shows two peaks at \sim 10 ^ { 12 \pm 0.5 } Hz and \sim 10 ^ { 21 \pm 1.0 } Hz ( \sim 0.3 mm and \sim 4 MeV ) , strongly resembling a low energy cutoff BL Lac object ( LBL ) .
The ratio of the two peaks shows an extreme Compton dominance ( C _ { D } = 1.4 \pm 0.4 ) , as in flat spectrum radio quasars ( FSRQs ) .
The presence of an additional ‘ optical/UV big bump ’ component may provide photons that cool the jet , suppressing the radio emission .