MEASURING A TRUNCATED DISK IN AQUILA X-1

• Main Authors: King, Ashley L. (Author), Tomsick, John A. (Author), Miller, Jon M. (Author), Chenevez, Jérôme (Author), Barret, Didier (Author), Boggs, Steven E. (Author), Chakrabarty, Deepto (Contributor), Christensen, Finn E. (Author), Craig, William W. (Author), Fürst, Felix (Author), Hailey, Charles J. (Author), Harrison, Fiona A. (Author), Parker, Michael L. (Author), Stern, Daniel (Author), Romano, Patrizia (Author), Walton, Dominic J. (Author), Zhang, William W. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2017-04-21T18:59:22Z.
• Subjects: Article
• Online Access: Get fulltext

We present NuSTAR and Swift observations of the neutron star Aquila X-1 during the peak of its 2014 July outburst. The spectrum is soft with strong evidence for a broad Fe Kα line. Modeled with a relativistically broadened reflection model, we find that the inner disk is truncated with an inner radius of 15 ± 3R[subscript G]. The disk is likely truncated by either the boundary layer and/or a magnetic field. Associating the truncated inner disk with pressure from a magnetic field gives an upper limit of B < 5 ± x 2 x 10[superscript 8]. Although the radius is truncated far from the stellar surface, material is still reaching the neutron star surface as evidenced by the X-ray burst present in the NuSTAR observation.