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Observational artifacts of Nuclear Spectroscopic Telescope Array: ghost rays and stray light

Madsen, Kristin K. and Christensen, Finn E. and Craig, William W. and Forster, Karl W. and Grefenstette, Brian W. and Harrison, Fiona A. and Miyasaka, Hiromasa and Rana, Vikram (2017) Observational artifacts of Nuclear Spectroscopic Telescope Array: ghost rays and stray light. Journal of Astronomical Telescopes, Instruments, and Systems, 3 (4). Art. No. 044003. ISSN 2329-4124. doi:10.1117/1.JATIS.3.4.044003.

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The Nuclear Spectroscopic Telescope Array (NuSTAR) launched in June 2012, flies two conical approximation Wolter-I mirrors at the end of a 10.15-m mast. The optics are coated with multilayers of Pt/C and W/Si that operate from 3 to 80 keV. Since the optical path is not shrouded, aperture stops are used to limit the field of view (FoV) from background and sources outside the FoV. However, there is still a sliver of sky (∼1.0  deg to 4.0 deg) where photons may bypass the optics altogether and fall directly on the detector array. We term these photons stray light. Additionally, there are also photons that do not undergo the focused double reflections in the optics, and we term these ghost rays. We present detailed analysis and characterization of these two components and discuss how they impact observations. Finally, we discuss how they could have been prevented and should be in future observatories.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Madsen, Kristin K.0000-0003-1252-4891
Christensen, Finn E.0000-0001-5679-1946
Forster, Karl W.0000-0001-5800-5531
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Miyasaka, Hiromasa0000-0002-8074-4186
Rana, Vikram0000-0003-1703-8796
Alternate Title:Observational Artifacts of NuSTAR: Ghost-rays and Stray-light
Additional Information:© 2017 The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Paper 17029P received Jun. 27, 2017; accepted for publication Oct. 3, 2017; published online Oct. 27, 2017. This work was supported under NASA Contract No. NNG08FD60C and 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. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. 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.
Group:NuSTAR, Space Radiation Laboratory, Astronomy Department
Funding AgencyGrant Number
Subject Keywords:Nuclear Spectroscopic Telescope Array; optics; satellite
Issue or Number:4
Record Number:CaltechAUTHORS:20180105-081533561
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Official Citation:Kristin K. Madsen, Finn E. Christensen, William W. Craig, Karl W. Forster, Brian W. Grefenstette, Fiona A. Harrison, Hiromasa Miyasaka, Vikram Rana, "Observational artifacts of Nuclear Spectroscopic Telescope Array: ghost rays and stray light," J. Ast. Inst. Sys. 3(4) 044003 (27 October 2017)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84115
Deposited By: Tony Diaz
Deposited On:05 Jan 2018 18:46
Last Modified:15 Nov 2021 20:17

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