Skip to main content

Research Repository

Advanced Search

The NuSTAR Hard X-Ray Survey of the Norma Arm Region

Fornasini, Francesca M.; Tomsick, John A.; Hong, JaeSub; Gotthelf, Eric V.; Bauer, Franz; Rahoui, Farid; Stern, Daniel; Bodaghee, Arash; Chiu, Jeng-Lun; Clavel, Maïca; Corral-Santana, Jesús; Hailey, Charles J.; Krivonos, Roman A.; Mori, Kaya; Alexander, David M.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Forster, Karl; Giommi, Paolo; Grefenstette, Brian W.; Harrison, Fiona A.; Hornstrup, Allan; Kitaguchi, Takao; Koglin, J.E.; Madsen, Kristin K.; Mao, Peter H.; Miyasaka, Hiromasa; Perri, Matteo; Pivovaroff, Michael J.; Puccetti, Simonetta; Rana, Vikram; Westergaard, Niels J.; Zhang, William W.

The NuSTAR Hard X-Ray Survey of the Norma Arm Region Thumbnail


Francesca M. Fornasini

John A. Tomsick

JaeSub Hong

Eric V. Gotthelf

Franz Bauer

Farid Rahoui

Daniel Stern

Arash Bodaghee

Jeng-Lun Chiu

Maïca Clavel

Jesús Corral-Santana

Charles J. Hailey

Roman A. Krivonos

Kaya Mori

Didier Barret

Steven E. Boggs

Finn E. Christensen

William W. Craig

Karl Forster

Paolo Giommi

Brian W. Grefenstette

Fiona A. Harrison

Allan Hornstrup

Takao Kitaguchi

J.E. Koglin

Kristin K. Madsen

Peter H. Mao

Hiromasa Miyasaka

Matteo Perri

Michael J. Pivovaroff

Simonetta Puccetti

Vikram Rana

Niels J. Westergaard

William W. Zhang


We present a catalog of hard X-ray sources in a square-degree region surveyed by the Nuclear Spectroscopic Telescope Array (NuSTAR) in the direction of the Norma spiral arm. This survey has a total exposure time of 1.7 Ms, and the typical and maximum exposure depths are 50 ks and 1 Ms, respectively. In the area of deepest coverage, sensitivity limits of 5 × 10−14 and 4 × 10−14 erg s−1 cm−2 in the 3–10 and 10–20 keV bands, respectively, are reached. Twenty-eight sources are firmly detected, and 10 are detected with low significance; 8 of the 38 sources are expected to be active galactic nuclei. The three brightest sources were previously identified as a low-mass X-ray binary, high-mass X-ray binary, and pulsar wind nebula. Based on their X-ray properties and multiwavelength counterparts, we identify the likely nature of the other sources as two colliding wind binaries, three pulsar wind nebulae, a black hole binary, and a plurality of cataclysmic variables (CVs). The CV candidates in the Norma region have plasma temperatures of ≈10–20 keV, consistent with the Galactic ridge X-ray emission spectrum but lower than the temperatures of CVs near the Galactic center. This temperature difference may indicate that the Norma region has a lower fraction of intermediate polars relative to other types of CVs compared to the Galactic center. The NuSTAR logN–logS distribution in the 10–20 keV band is consistent with the distribution measured by Chandra at 2–10 keV if the average source spectrum is assumed to be a thermal model with kT ≈ 15 keV, as observed for the CV candidates.


Fornasini, F. M., Tomsick, J. A., Hong, J., Gotthelf, E. V., Bauer, F., Rahoui, F., …Zhang, W. W. (2017). The NuSTAR Hard X-Ray Survey of the Norma Arm Region. Astrophysical Journal Supplement, 229(2), Article 33.

Journal Article Type Article
Acceptance Date Feb 19, 2017
Online Publication Date Apr 6, 2017
Publication Date Apr 6, 2017
Deposit Date Jun 21, 2017
Publicly Available Date Jul 3, 2017
Journal Astrophysical Journal Supplement
Print ISSN 0067-0049
Electronic ISSN 1538-4365
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 229
Issue 2
Article Number 33
Public URL


Published Journal Article (2.9 Mb)

Copyright Statement
© 2017. The American Astronomical Society. All rights reserved.

You might also like

Downloadable Citations