Gallo, Luigi C.; Grupe, D.; Schartel, N.; Komossa, S.; Miniutti, G.; Fabian, A. C.; Santos-Lleo, M. (Oxford University Press, 2011-03)
In 2009 March the well-studied quasar, PG 0844+349, was discovered with Swift to be in an X-ray weak state. A follow-up XMM–Newton observation several weeks later generated a good-quality spectrum of the source, showing ...