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Effective area calibration of the Nuclear Spectroscopic Telescope Array

Madsen, Kristin K. and Forster, Karl and Grefenstette, Brian W. and Harrison, Fiona A. and Miyasaka, Hiromasa (2022) Effective area calibration of the Nuclear Spectroscopic Telescope Array. Journal of Astronomical Telescopes, Instruments, and Systems, 8 (3). Art. No. 034003. ISSN 2329-4124. doi:10.1117/1.jatis.8.3.034003.

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We present here the updated calibration of the Nuclear Spectroscopic Telescope Array, which was performed using data on the Crab accumulated over the last nine years in orbit. The basis for this new calibration contains over 250 ks of focused Crab observations (imaged through the optics) and over 500 ks of stray-light (SL) Crab observations (not imaged through optics). We measured an epoch averaged spectrum of the SL Crab data and define a canonical Crab spectrum of Γ = 2.103 ± 0.001 and N = 9.69 ± 0.02 keV⁻¹ cm⁻² s⁻¹ at 1 keV, which we use as our calibration standard. This calibration released in the Calibration Data Base update 20211020 provides significant updates to: (1) the detector absorption component, (2) the detector response function, and (3) the effective area vignetting function. The calibration improves agreement between FPMA and FPMB across detectors with a standard deviation of 1.7% for repeat observations between off-axis angles of 1' to 4'. As a consequence of the measured SL observations, the absolute flux of the instrument has increased by 5% to 15%, with 5% below 1' off-axis angle, 10% between 1 and 2', and 15% above 4'.

Item Type:Article
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URLURL TypeDescription ItemConference Paper
Madsen, Kristin K.0000-0003-1252-4891
Forster, Karl0000-0001-5800-5531
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Miyasaka, Hiromasa0000-0002-8074-4186
Additional Information: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. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Space Science Data Center (SSDC, Italy) and the California Institute of Technology (USA). This material is based upon work supported by NASA (award number 80GSFC21M0002). We thank Murray Brightman, Renee Ludlam, Guglielmo Mastroserio, and Riley Connors for performing the case study re-analyses in Sec. 7.2.
Group:Astronomy Department, Space Radiation Laboratory, NuSTAR
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Issue or Number:3
Record Number:CaltechAUTHORS:20221024-125854800.17
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117548
Deposited By: Research Services Depository
Deposited On:01 Nov 2022 20:42
Last Modified:01 Nov 2022 20:42

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