Initial Results from NuSTAR Observations of the Norma Arm
Results are presented for an initial survey of the Norma Arm gathered with the focusing hard X-Ray Telescope NuSTAR. The survey covers 0.2 deg^2 of sky area in the 3-79 keV range with a minimum and maximum raw depth of 15 ks and 135 ks, respectively. Besides a bright black-hole X-ray binary in outburst (4U 1630–47) and a new X-ray transient (NuSTAR J163433–473841), NuSTAR locates three sources from the Chandra survey of this region whose spectra are extended above 10 keV for the first time: CXOU J163329.5–473332, CXOU J163350.9–474638, and CXOU J163355.1–473804. Imaging, timing, and spectral data from a broad X-ray range (0.3-79 keV) are analyzed and interpreted with the aim of classifying these objects. CXOU J163329.5–473332 is either a cataclysmic variable or a faint low-mass X-ray binary. CXOU J163350.9–474638 varies in intensity on year-long timescales, and with no multi-wavelength counterpart, it could be a distant X-ray binary or possibly a magnetar. CXOU J163355.1–473804 features a helium-like iron line at 6.7 keV and is classified as a nearby cataclysmic variable. Additional surveys are planned for the Norma Arm and Galactic Center, and those NuSTAR observations will benefit from the lessons learned during this pilot study.
Additional Information© 2014 American Astronomical Society. Received 2014 February 12; accepted 2014 June 30; published 2014 July 28. 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 theASI Science Data Center (ASDC, Italy) and the California Institute of Technology. This research has made use of: data obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC) provided by NASA's Goddard Space Flight Center; NASA's Astrophysics Data System Bibliographic Services; and the SIMBAD database operated at CDS, Strasbourg, France. F.M.F. acknowledges support from the National Science Foundation Graduate Research Fellowship. F.E.B. acknowledges support from Basal-CATA PFB-06/2007, CONICYT-Chile (FONDECYT 1141218 and "EMBIGGEN" Anillo ACT1101), and Project IC120009 "Millennium Institute of Astrophysics (MAS)" of Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo.
Published - Bodaghee_2014p68.pdf
Submitted - 1407.0023v1.pdf