NuSTAR Spectral Analysis beyond 79 keV with Stray Light

Mastroserio G, Grefenstette BW, Thalhammer P, Buisson DJK, Brumback MC, Ludlam RM, Connors RMT, Garcia JA, Grinberg V, Madsen KK, Miyasaka H, Tomsick JA, Wilms J (2022)


Publication Type: Journal article

Publication year: 2022

Journal

Book Volume: 941

Journal Issue: 1

DOI: 10.3847/1538-4357/ac8c94

Abstract

Due to the structure of the NuSTAR telescope, photons at a large off axis (>1 degrees) can reach the detectors directly (stray light), without passing through the instrument optics. At these off-axis angles NuSTAR essentially turns into a collimated instrument and the spectrum can extend to energies above the Pt K edge (79 keV) of the multilayers, which limits the effective area bandpass of the optics. We present the first scientific spectral analysis beyond 79 keV using a Cygnus X-1 observation in StrayCats: the catalog of stray light observations. This serendipitous stray light observation occurred simultaneously with an INTEGRAL observation. When the spectra are modeled together in the 30-120 keV energy band, we find that the NuSTAR stray light flux is well calibrated and constrained to be consistent with the INTEGRAL flux at the 90% confidence level. Furthermore, we explain how to treat the background of the stray light spectral analysis, which is especially important at high energies.

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How to cite

APA:

Mastroserio, G., Grefenstette, B.W., Thalhammer, P., Buisson, D.J.K., Brumback, M.C., Ludlam, R.M.,... Wilms, J. (2022). NuSTAR Spectral Analysis beyond 79 keV with Stray Light. Astrophysical Journal, 941(1). https://doi.org/10.3847/1538-4357/ac8c94

MLA:

Mastroserio, G., et al. "NuSTAR Spectral Analysis beyond 79 keV with Stray Light." Astrophysical Journal 941.1 (2022).

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