Gallo, Luigi C.; Bachev, R.; Grupe, D.; Boeva, S.; Ovcharov, E.; Valcheva, A.; Semkov, E.; Georgiev, Ts. (Oxford University Press, 2009-10)
We present the results from a monitoring campaign of the Narrow-Line Seyfert 1 galaxy PG 1211+143. The object was monitored with ground-based facilities (UBVRI photometry; from 2007 February to July) and with Swift [X-ray ...