We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548 , selected as candidates for high-redshift blazars from unassociated sources in the Fermi Large Area Telescope Second Source Catalog .
We utilize the Suzaku satellite and the VLBI Exploration of Radio Astrometry ( VERA ) telescopes for X-ray and radio observations , respectively .
For 2FGL J0923.5+1508 , a possible radio counterpart NVSS J092357+150518 is found at 1.4 GHz from an existing catalog , but we do not detect any X-ray emission from it and derive a flux upper limit F _ { 2 - 8 keV } < 1.37 \times 10 ^ { -14 } erg cm ^ { -2 } s ^ { -1 } .
Radio observations at 6.7 GHz also result in an upper limit of S _ { 6.7 GHz } < 19 mJy , implying a steep radio spectrum that is not expected for a blazar .
On the other hand , we detect X-rays from NVSS J150229+555204 , the potential 1.4 GHz radio counterpart of 2FGL J1502.1+5548 .
The X-ray spectrum can be fitted with an absorbed power-law model with a photon index \gamma = 1.8 ^ { +0.3 } _ { -0.2 } and the unabsorbed flux is F _ { 2 - 8 keV } = 4.3 ^ { +1.1 } _ { -1.0 } \times 10 ^ { -14 } erg cm ^ { -2 } s ^ { -1 } .
Moreover , we detect unresolved radio emission at 6.7 GHz with flux S _ { 6.7 GHz } = 30.1 mJy , indicating a compact , flat-spectrum radio source .
If NVSS J150229+555204 is indeed associated with 2FGL J1502.1+5548 , we find that its multiwavelength spectrum is consistent with a blazar at redshift z \sim 3 - 4 .