ner_tags: O O O O O O B-Person I-Person B-Person I-Person O B-Person I-Person O O O O O O O O O O B-Person I-Person O O O O O O O B-Organization I-Organization I-Organization I-Organization O O B-Fellowship I-Fellowship I-Fellowship I-Fellowship O O O O O O O O B-Organization B-Grant I-Grant I-Grant O O O B-Grant O B-Person O O B-Organization O O O B-Grant O B-Person
tokens: The authors would like to thank Bence Bécsy, Gergely Dálya, and Ákos Szölgyén for useful discussions and for valuable comments on the manuscript. Péter Raffai is grateful for the support of the Hungarian Academy of Sciences through the ‘Bolyai János’ Research Scholarship programme. We also acknowledge financial support from the NASA Astrophysics Theory Program under grant no. NNX11AE05G (to ZH) and from OTKA under grant no. 101666 (to ZF).