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Hard X-Ray Emission from Sh 2-104: A NuSTAR Search for Gamma-Ray Counterparts

Gotthelf, E. V. and Mori, K. and Aliu, E. and Paredes, J. M. and Tomsick, J. A. and Boggs, S. E. and Christensen, F. E. and Craig, W. W. and Hailey, C. J. and Harrison, F. A. and Hong, J. S. and Rahoui, F. and Stern, D. and Zhang, W. W. (2016) Hard X-Ray Emission from Sh 2-104: A NuSTAR Search for Gamma-Ray Counterparts. Astrophysical Journal, 826 (1). Art. No. 25. ISSN 0004-637X. doi:10.3847/0004-637X/826/1/25.

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We present NuSTAR hard X-ray observations of Sh 2–104, a compact H II region containing several young massive stellar clusters (YMSCs). We have detected distinct hard X-ray sources coincident with localized VERITAS TeV emission recently resolved from the giant gamma-ray complex MGRO J2019+37 in the Cygnus region. Fainter, diffuse X-rays coincident with the eastern YMSC in Sh2-104 likely result from the colliding winds of a component star. Just outside the radio shell of Sh 2–104 lies 3XMM J201744.7+365045 and a nearby nebula, NuSTAR J201744.3+364812, whose properties are most consistent with extragalactic objects. The combined XMM-Newton and NuSTAR spectrum of 3XMM J201744.7+365045 is well-fit to an absorbed power-law model with N_H = (3.1 ± 1.0) x 10^(22) cm^(−2) and a photon index Γ = 2.1 ± 0.1. Based on possible long-term flux variation and the lack of detected pulsations (≤43% modulation), this object is likely a background active galactic nucleus rather than a Galactic pulsar. The spectrum of the NuSTAR nebula shows evidence of an emission line at E = 5.6 keV, suggesting an optically obscured galaxy cluster at z = 0.19 ± 0.02 (d = 800 Mpc) and L X = 1.2 × 10^(44) erg s^(−1). Follow-up Chandra observations of Sh 2–104 will help identify the nature of the X-ray sources and their relation to MGRO J2019+37. We also show that the putative VERITAS excess south of Sh 2–104, is most likely associated with the newly discovered Fermi pulsar PSR J2017+3625 and not the H II region.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gotthelf, E. V.0000-0003-3847-3957
Mori, K.0000-0002-9709-5389
Tomsick, J. A.0000-0001-5506-9855
Boggs, S. E.0000-0001-9567-4224
Christensen, F. E.0000-0001-5679-1946
Harrison, F. A.0000-0003-2992-8024
Rahoui, F.0000-0001-7655-4120
Stern, D.0000-0003-2686-9241
Zhang, W. W.0000-0002-1426-9698
Additional Information:© 2016 The American Astronomical Society. Received 2016 February 2; revised 2016 April 21; accepted 2016 May 8; published 2016 July 18. 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). E.V.G. acknowledges partial support by the National Aeronautics and Space Administration through XMM-Newton Award Number NNX15AG28G and Chandra Award Number G05-16061X, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. J.M.P. acknowledges support by the Spanish MINECO under grants AYA2013-47447-C3-1-P, MDM-2014-0369 of ICCUB (Unidad de Excelencia “María de Maeztu”), and the Catalan DEC grant 2014 SGR 86 and ICREA Academia.
Funding AgencyGrant Number
Ministerio de Economía y Competitividad (MINECO)AYA2013-47447-C3-1-P
Unidad de Excelencia “María de Maeztu”MDM-2014-0369
Catalan DEC2014 SGR 86
Subject Keywords:ISM: individual objects (Sh 2-104, MGRO J2019+37, 3XMM J201744.7+365045, VER J2019+368) – pulsars: individual (NuSTAR J201744.3+364812) – stars: neutron
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-42
Issue or Number:1
Record Number:CaltechAUTHORS:20160801-142718338
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:69362
Deposited By: Tony Diaz
Deposited On:01 Aug 2016 22:02
Last Modified:11 Nov 2021 04:13

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