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High-energy X-Ray Detection of G359.89–0.08 (Sgr A–E): Magnetic Flux Tube Emission Powered by Cosmic Rays?

Zhang, Shou and Hailey, Charles J. and Baganoff, Frederick K. and Bauer, Franz E. and Boggs, Steven E. and Craig, William W. and Christensen, Finn E. and Gotthelf, Eric V. and Harrison, Fiona A. and Mori, Kaya and Nynka, Melania and Stern, Daniel and Tomsick, John A. and Zhang, William W. (2014) High-energy X-Ray Detection of G359.89–0.08 (Sgr A–E): Magnetic Flux Tube Emission Powered by Cosmic Rays? Astrophysical Journal, 784 (1). Art. No. 6. ISSN 0004-637X. doi:10.1088/0004-637X/784/1/6.

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We report the first detection of high-energy X-ray (E > 10 keV) emission from the Galactic center non-thermal filament G359.89–0.08 (Sgr A–E) using data acquired with the Nuclear Spectroscopic Telescope Array (NuSTAR). The bright filament was detected up to ~50 keV during a NuSTAR Galactic center monitoring campaign. The featureless power-law spectrum with a photon index Γ ≈ 2.3 confirms a non-thermal emission mechanism. The observed flux in the 3-79 keV band is F_X = (2.0 ± 0.1) × 10^(–12) erg cm^(–2) s^(–1), corresponding to an unabsorbed X-ray luminosity L_X = (2.6 ± 0.8) × 10^(34) erg s^(–1) assuming a distance of 8.0 kpc. Based on theoretical predictions and observations, we conclude that Sgr A–E is unlikely to be a pulsar wind nebula (PWN) or supernova remnant-molecular cloud (SNR-MC) interaction, as previously hypothesized. Instead, the emission could be due to a magnetic flux tube which traps TeV electrons. We propose two possible TeV electron sources: old PWNe (up to ~100 kyr) with low surface brightness and radii up to ~30 pc or MCs illuminated by cosmic rays (CRs) from CR accelerators such as SNRs or Sgr A^*.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Bauer, Franz E.0000-0002-8686-8737
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Gotthelf, Eric V.0000-0003-3847-3957
Harrison, Fiona A.0000-0003-2992-8024
Mori, Kaya0000-0002-9709-5389
Nynka, Melania0000-0002-3310-1946
Stern, Daniel0000-0003-2686-9241
Tomsick, John A.0000-0001-5506-9855
Zhang, William W.0000-0002-1426-9698
Additional Information:© 2014 American Astronomical Society. Received 2013 November 19; accepted 2014 January 25; published 2014 February 25. 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 (USA). S.Z. is partially supported by NASA Headquarters under the NASA Earth and Space Science Fellowship Program— Grant “NNX13AM31.” The authors wish to thank Mark Morris for allowing them to view the recently acquired JVLA 6 cm continuum radio map of Sgr A−E.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:Galaxy: center; X-rays: individual (Sgr A–E, G359.89–0.08, XMM J17450–2904); X-rays: ISM
Issue or Number:1
Record Number:CaltechAUTHORS:20140605-111540676
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Official Citation:High-energy X-Ray Detection of G359.89–0.08 (Sgr A–E): Magnetic Flux Tube Emission Powered by Cosmic Rays? Shuo Zhang et al. 2014 ApJ 784 6
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46098
Deposited By: Ruth Sustaita
Deposited On:05 Jun 2014 18:42
Last Modified:10 Nov 2021 17:20

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