First hard x-ray detection of the non-thermal emission around the arches cluster: Morphology and spectral studies with NuSTAR

Journal Article · Sat Feb 01 00:00:00 EST 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/781/2/107· OSTI ID:22348091

Krivonos, Roman A.; Tomsick, John A.; Barriere, Nicolas M.; Bodaghee, Arash; Boggs, Steven E.; Craig, William W. ^[1]; Bauer, Franz E. ^[2]; Baganoff, Frederick K. ^[3]; Christensen, Finn E. ^[4]; Grefenstette, Brian W.; Harrison, Fiona A.; Madsen, Kristin K. ^[5]; Hailey, Charles J.; Mori, Kaya; Nynka, Melania ^[6]; Hong, JaeSub ^[7]; Stern, Daniel ^[8]

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1. Space Science Lab, University of California, Berkeley, CA 94720 (United States)
2. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Catlica de Chile, Casilla 306, Santiago 22 (Chile)
3. MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA 02139 (United States)
4. DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
5. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
6. Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
7. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
8. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

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 scenarioþ.

• OSTI ID: 22348091
• Journal Information: Astrophysical Journal, Vol. 781, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COSMIC RADIATION
DETECTION
EMISSION
EXCITATION
GALAXIES
HARD X RADIATION
KEV RANGE
LIMITING VALUES
LUMINOSITY
PHOTOIONIZATION
PROTONS
REFLECTION
SPATIAL DISTRIBUTION
SPECTRA
STAR CLUSTERS
STARS