Possible ~1 hour quasi-periodic oscillation in narrow-line Seyfert 1 galaxy MCG–06–30–15 Alok C. Gupta, Ashutosh Tripathi, Paul J. Wiita, Minfeng Gu, Cosimo Bambi and Luis C. Ho A&A, 616 (2018) L6 Published online: 15 August 2018 DOI: 10.1051/0004-6361/201833629