Is the X-ray bright <i>z</i> = 5.5 quasar SRGE J170245.3+130104 a blazar?

Jets may have contributed to promoting the growth of seed black holes in early Universe, and thus observations radio-loud high-redshift quasars are crucial understanding evolution supermassive holes. Here we report radio properties an X-ray bright $z=5.5$ quasar, SRGE J170245.3+130104 (J1702+1301). Our high-resolution images reveal counterpart at optical position J1702+1301, while another component is also detected $\sim$23.5\arcsec\ southwest. analysis suggests that this southwest associated with a foreground galaxy $z\approx 0.677$, which mixed J1702+1301 low-frequency low-resolution images. After removing contamination from source, recalculated loudness be $R>$1100, consistent those blazars. exhibits flat spectrum ($\alpha = -0.17 \pm 0.05$, $S \propto \nu^\alpha$) between 0.15 5 GHz; above GHz, it shows rising shape, spectral index $\alpha^{8.2}_{4.7}$ appears correlated variation flux density: burst states, becomes larger. displays distinct variability on timescales weeks years source's rest frame. These properties, including high loudness, spectrum, rapid variability, tend support as blazar.