tokens: Acknowledgements This study is based on observations with XMMNewton , an ESA Science Mission with instruments and contributions directly funded by ESA Member states and the USA (NASA), and with Swift , a NASA mission with international participation. We would like to thank the anonymous referee for the useful comments and suggestions that helped improve the manuscript. The XMMNewton project is supported by the Bundesministerium fr Wirtschaft und Technologie/Deutsches Zentrum fr Luft- und Raumfahrt (BMWi/DLR, FKZ 50 OX 0001) and the Max-Planck Society. The OGLE project has received funding from the European Research Council under the European Communitys Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 246678 to AU. We thank the Swift team for accepting and carefully scheduling the target of opportunity observations, and we acknowledge the use of public data from the Swift data archive. GV acknowledges support from the BMWi/DLR grant FKZ 50 OR 1208. PM acknowledges support by the Centre National dtudes Spatiales (CNES). Last but not least, we wish to thank Dr. M. Petropoulou and Dr. F. Koliopanos for their useful comments.
ner_tags: O O O O O O O O B-Telescope O O B-Organization O O O O O O O O O B-Organization O O O O B-Location B-Organization O O B-Observatory O O B-Organization O O O O O O O O O O O O O O O O O O O O O O O O B-Telescope O O O O O B-Organization I-Organization I-Organization I-Organization I-Organization B-Organization I-Organization I-Organization I-Organization I-Organization B-Organization B-Grant I-Grant I-Grant I-Grant O O B-Organization I-Organization O B-Survey O O O O O O B-Organization I-Organization I-Organization O O B-Organization I-Organization B-Grant I-Grant I-Grant B-Grant B-Grant I-Grant I-Grant I-Grant O B-Person O O O B-Observatory O O O O O O O O O O O O O O O O O O O O O B-Archive I-Archive I-Archive B-Person O O O O B-Organization B-Grant I-Grant I-Grant I-Grant I-Grant B-Person O O O O B-Organization I-Organization I-Organization I-Organization B-Organization O O O O O O O O B-Person I-Person I-Person O B-Person I-Person I-Person O O O O