CaltechAUTHORS
Published March 10, 2016 | Version Published + Submitted
Journal Article Open

Measuring A Truncated Disk in Aquila X-1

Creators

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 ± 3R_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 ± 2 x 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.

Additional Information

© 2016 American Astronomical Society. Received 2015 October 19; accepted 2016 February 22; published 2016 March 7. The authors thank the referee for their invaluable comments. A.L.K. would like to thank the support for this work, which was provided by NASA through Einstein Postdoctoral Fellowship grant number PF4-150125 awarded by the Chandra X-ray Center, operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. P.R. acknowledges financial contribution from contract ASI-INAF I/004/11/0 and ASI-INAF I/037/12/0. J.C. is grateful for financial support from ESA/PRODEX No. 90057. This work made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA).

Attached Files

Published - kingaL-L29.pdf

Submitted - 1602.07664v1.pdf

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1602.07664v1.pdf

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Additional details

Identifiers

Eprint ID
65468
Resolver ID
CaltechAUTHORS:20160318-071512595

Related works

Describes
http://arxiv.org/abs/1602.07664 (URL)

Funding

NASA Einstein Fellowship
PF4-150125
NASA
NAS8-03060
Agenzia Spaziale Italiana (ASI)
I/004/ 11/0
Agenzia Spaziale Italiana (ASI)
I/037/12/0
ESA/PRODEX
90057
Istituto Nazionale di Astrofisica (INAF)
NASA/JPL/Caltech

Dates

Created
2016-03-18
Created from EPrint's datestamp field
Updated
2021-11-10
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
NuSTAR, Space Radiation Laboratory
Other Numbering System Name
Space Radiation Laboratory
Other Numbering System Identifier
2016-62