ner_tags: 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 B-Organization O O O O O O B-Telescope O O O B-Location I-Location I-Location I-Location O O B-Organization I-Organization I-Organization O O B-Location B-Observatory I-Observatory I-Observatory I-Observatory I-Observatory I-Observatory O O B-Organization I-Organization I-Organization I-Organization I-Organization O O O O O O O O O O B-Database I-Database I-Database O O O O O O O O O
tokens: Based on observations obtained with XMM–Newton , an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Based on observations made with the WHT operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. We acknowledge with thanks the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this research.