An active state of the BL Lacertae object Markarian 421 detected by INTEGRAL in April 2013

PIAN, E., TUERLER, M., FIOCCHI, M., BOISSAY, R., BAZZANO, A., FOSCHINI, L., TAVECCHIO, F., BIANCHIN, V., CASTIGNANI, G., FERRIGNO, C., RAITERI, C.M., VILLATA, M., BECKMANN, V., D'AMMANDO, F., HUDEC, René, MALAGUTI, G., MARASCHI, L., PURSIMO, T., ROMANO, P., SOLDI, S., STAMERRA, A., TREVES, A., UBERTINI, P., VERCELLONE, S., WALTER, R. An active state of the BL Lacertae object Markarian 421 detected by INTEGRAL in April 2013. Astronomy & Astrophysics. 2014, 570(October), A77/1-A77/9. ISSN 0004-6361. E-ISSN 1432-0746. Available: doi: 10.1051/0004-6361/201322191