Is BZB J1450+5201 the most distant gamma-ray BL Lacertae object?

Neng-Hui Liao, Jin-Ming Bai, Jian-Guo Wang, Hong-Tao Liu, Jiu-Jia Zhang, Ning Jiang, Zun-Li Yuan, Liang Chen
2015 Research in Astronomy and Astrophysics  
BL Lacertae (BL Lac) objects at high redshifts ($z\geq 2$) are rarely detected. Through careful analysis of the SDSS spectrum, BZB J1450+5201 is confirmed to be a high-$z$ BL Lac object with $z\geq$ 2.471 by identifying the Ly$\alpha$ 1216 and CIV 1548/1550 absorption lines. This indicates that BZB J1450+5201 is the most distant BL Lac object discovered to date. Careful analysis of the five-year \fermi data of 2FGL J1451.0+5159 shows that its $\gamma$-ray emission is robust with confidence
more » ... ith confidence level of 6.2$\sigma$ at 1-3 GeV and 6.7$\sigma$ at 3-10 GeV, and that the confusion of bright neighbor is negligible, which can not be fixed in the analysis of the two-year data. Meanwhile, 2FGL J1451.0+5159 is confirmed to be associated with BZB J1450+5201 using the five-year data. The analysis of multiwavelength data, from radio to $\gamma$-ray energies, indicates BZB J1450+5201 is an intermediate synchrotron peaked (ISP) source and consistent with distributions of other ISP sources at lower redshifts in the second LAT AGN catalog. The pure SSC model seems to be disfavoured, while scattering of weak external emission plus SSC process can provide a satisfactory description of the broadband emission.
doi:10.1088/1674-4527/15/3/002 fatcat:lbocxit6lraeln2pelflsdve5a