Measuring a Truncated Disk in Aquila X-1

Journal
Date Issued
2016
Author(s)
King, Ashley L.
•
Tomsick, John A.
•
Miller, Jon M.
•
Chenevez, Jérôme
•
Barret, Didier
•
Boggs, Steven E.
•
Chakrabarty, Deepto
•
Christensen, Finn E.
•
Craig, William W.
•
Fürst, Felix
•
Hailey, Charles J.
•
Harrison, Fiona A.
•
Parker, Michael L.
•
Stern, Daniel
•
•
Walton, Dominic J.
•
Zhang, William W.
DOI
Abstract
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+/- 3{R}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\lt 5+/- 2× {10}8 G. 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.
Volume
819
Issue
2
Start page
L29
Uri
Url
Issn Identifier
2041-8205
Ads BibCode
2016ApJ...819L..29K
Rights
open.access
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