Discovery of an X-Ray Photoionized Optical Nebula and a Radio Nebula Associated with the ULX NGC 4861 X-1

Autor: Hang Gong, Ryan Urquhart, Alexandr Vinokurov, Yu Bai, Antonio Cabrera-Lavers, Sergei Fabrika, Liang Wang, Jifeng Liu
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: The Astrophysical Journal, Vol 958, Iss 1, p 24 (2023)
Druh dokumentu: article
ISSN: 1538-4357
DOI: 10.3847/1538-4357/acf8c3
Popis: We have conducted long-slit spectroscopic observations and analyzed archival radio data for the ultraluminous X-ray source (ULX) NGC 4861 X-1. Our spectral line analysis unveils NGC 4861 X-1 as the fourth ULX situated within an X-ray photoionized nebula, following three previous findings made approximately two decades ago. Remarkably, we discover NGC 4861 X-1 also possesses a radio nebula emitting optically thin synchrotron radiation, which contradicts its X-ray photoionization and raises doubts about the four ULXs being a mere coincidence. Instead of gradually accumulating from different bands bit by bit, our multiband discovery is made all at once. Moreover, we tentatively perceive a faint continuum spectrum of the optical nebula. Further observations are needed to ascertain its radio structures and verify the optical continuum.
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