1. INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy
2. INAF – Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano, Italy
3. INAF/IASF Milano, Via Alfonso Corti 12, I-20133 Milano, Italy
4. XMM–Newton Science Operations Centre, ESAC/ESA, PO Box 78, E-28691 Villanueva de la Canãda, Madrid, Spain
5. Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Quantum, Vesilinnantie 5, FIN-20014 Turku, Finland
6. Aalto University Metsähovi Radio Observatory, Metsähovintie 114, FIN-02540 Kylmälä, Finland
7. INAF – Istituto di Radioastronomia, Via Gobetti 101, I-40129 Bologna, Italy
8. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802, USA