SDSS J154751.94+025550 with double-peaked broad H ? but single-peaked broad H ?: a candidate for central binary black hole system?

In this manuscript, an interesting blue Active Galactic Nuclei (AGN) SDSS J154751.94+025550 (=SDSS J1547) is reported with very different line profiles of broad Balmer emission lines: double-peaked H$\beta$ but single-peaked H$\alpha$. J1547 the first AGN detailed discussions on lines, besides simply mentioned lines in candidate for a binary black hole (BBH) system J0159+0105. The can be well explained by physical conditions to two central BLRs BBH J1547. Furthermore, long-term light curve from CSS described sinusoidal function periodicity about 2159days, providing further evidence support expected Therefore, it treat as intrinsic indicators systems AGN. Under assumptions systems, 0.125\% have lines. Future study more could provide clues indicator systems.