出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present European VLBI Network (EVN) observations at 5 GHz of the candidate binary blackhole system SDSS J1536+0441. Both components, J1536+0441A and J1536+0441B, observed by the VLA at 8.5 GHz and separated by 0.97 arcsec are detected with high S/N, proving the presence of two compactAGNs with radio luminosity LR ∼1040 erg s−1. From a comparisonwith published 8.5 & 22.5 GHz flux densities, we derive an estimate of the radio spectral index of the two radio sources. Both sources have flat or inverted radio spectrum. In particular, J1536+0441A has a rising spectrum up to ≃ 30 GHz, rest frame. Given the moderate brightness temperature derived from the flux and fitted size of J1536+0441A, we suggest that thermal free-free emission from an X-ray-heated disc may be powering the radio emission in J1536+0441A.
