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First Hard X-Ray Detection of the Non-thermal Emission around the Arches Cluster: Morphology and Spectral Studies with NuSTAR

Krivonos, Roman A. and Tomsick, John A. and Bauer, Franz E. and Baganoff, Frederick K. and Barriere, Nicolas M. and Bodaghee, Arash and Boggs, Steven E. and Christensen, Finn E. and Craig, William W. and Grefenstette, Brian W. and Hailey, Charles J. and Harrison, Fiona A. and Hong, JaeSub and Madsen, Kristin K. and Mori, Kaya and Nynka, Melania and Stern, Daniel and Zhang, William W. (2014) First Hard X-Ray Detection of the Non-thermal Emission around the Arches Cluster: Morphology and Spectral Studies with NuSTAR. Astrophysical Journal, 781 (2). Art. No. 107. ISSN 0004-637X. doi:10.1088/0004-637X/781/2/107.

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The Arches cluster is a young, densely packed massive star cluster in our Galaxy that shows a high level of star formation activity. The nature of the extended non-thermal X-ray emission around the cluster remains unclear. The observed bright Fe Kα line emission at 6.4 keV from material that is neutral or in a low ionization state can be produced either by X-ray photoionization or by cosmic-ray particle bombardment or both. In this paper, we report on the first detection of the extended emission around the Arches cluster above 10 keV with the NuSTAR mission, and present results on its morphology and spectrum. The spatial distribution of the hard X-ray emission is found to be consistent with the broad region around the cluster where the 6.4 keV line is observed. The interpretation of the hard X-ray emission within the context of the X-ray reflection model puts a strong constraint on the luminosity of the possible illuminating hard X-ray source. The properties of the observed emission are also in broad agreement with the low-energy cosmic-ray proton excitation scenario.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Krivonos, Roman A.0000-0003-2737-5673
Tomsick, John A.0000-0001-5506-9855
Bauer, Franz E.0000-0002-8686-8737
Bodaghee, Arash0000-0002-7315-3732
Boggs, Steven E.0000-0001-9567-4224
Christensen, Finn E.0000-0001-5679-1946
Grefenstette, Brian W.0000-0002-1984-2932
Harrison, Fiona A.0000-0003-2992-8024
Madsen, Kristin K.0000-0003-1252-4891
Mori, Kaya0000-0002-9709-5389
Nynka, Melania0000-0002-3310-1946
Stern, Daniel0000-0003-2686-9241
Zhang, William W.0000-0002-1426-9698
Additional Information:© 2014 American Astronomical Society. Received 2013 September 30; accepted 2013 December 7; published 2014 January 15. 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). F.E.B. acknowledges support from Basal-CATA (PFB-06/2007) and CONICYT-Chile (FONDECYT 1101024 and Anillo ACT1101). R.K. thanks Eugene Churazov for fruitful discussions and valuable suggestions to the paper. Facility: NuSTAR
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1101024
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)Anillo ACT1101
Subject Keywords:cosmic rays; Galaxy: center; ISM: general; X-rays: individual (Arches cluster)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2014-70
Issue or Number:2
Record Number:CaltechAUTHORS:20140321-092114962
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Official Citation:First Hard X-Ray Detection of the Non-thermal Emission around the Arches Cluster: Morphology and Spectral Studies with NuSTAR Roman A. Krivonos et al. 2014 ApJ 781 107
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44441
Deposited By: Ruth Sustaita
Deposited On:21 Mar 2014 16:46
Last Modified:10 Nov 2021 16:52

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