@article{3bff7d05e5c641148a624f00a1e08f73,
title = "A Potential Cyclotron Resonant Scattering Feature in the Ultraluminous X-Ray Source Pulsar NGC 300 ULX1 Seen by NuSTAR and XMM-Newton",
abstract = "Based on phase-resolved broadband spectroscopy using XMM-Newton and NuSTAR, we report on a potential cyclotron resonant scattering feature (CRSF) at E ∼ 13 keV in the pulsed spectrum of the recently discovered ultraluminous X-ray source (ULX) pulsar NGC 300 ULX1. If this interpretation is correct, the implied magnetic field of the central neutron star is B ∼ 1012 G (assuming scattering by electrons), similar to that estimated from the observed spin-up of the star, and also similar to known Galactic X-ray pulsars. We discuss the implications of this result for the connection between NGC 300 ULX1 and the other known ULX pulsars, particularly in light of the recent discovery of a likely proton cyclotron line in another ULX, M51 ULX-8.",
author = "Walton, {D. J.} and M. Bachetti and F. F{\"u}rst and D. Barret and M. Brightman and Fabian, {A. C.} and Grefenstette, {B. W.} and Harrison, {F. A.} and M. Heida and J. Kennea and P. Kosec and Lau, {R. M.} and Madsen, {K. K.} and Middleton, {M. J.} and C. Pinto and Steiner, {J. F.} and N. Webb",
note = "Funding Information: The authors would like to thank the reviewer for timely and positive feedback. D.J.W. and M.J.M. acknowledge support from STFC Ernest Rutherford fellowships. A.C.F. acknowledges ERC Advanced Grant 340442, P.K. acknowledges support from the STFC, and D.B. acknowledges support from the French Space Agency (CNES). This research has made use of data obtained with NuSTAR, a project led by Caltech, funded by NASA and managed by NASA/JPL, and has utilized the NUSTARDASsoftware package, jointly developed by the ASDC (Italy) and Caltech (USA). This work has also made use of data obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States. Facilities: NuSTAR, XMM. Publisher Copyright: {\textcopyright} 2018. The American Astronomical Society. All rights reserved.",
year = "2018",
month = apr,
day = "10",
doi = "10.3847/2041-8213/aabadc",
language = "English (US)",
volume = "857",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",
}