Extended Gamma-Ray Emission from the G25.0+0.0 Region: A Star-forming Region Powered by the Newly Found OB Association?
Katsuta J, Uchiyama Y, Funk S (2017)
Publication Type: Journal article
Publication year: 2017
Journal
Book Volume: 839
Journal Issue: 2
Abstract
We report a study of extended gamma-ray emission with the Large Area Telescope (LAT) on board the Fermi Gammaray Space Telescope, which is likely to be the second case of gamma-ray detection from a star-forming region (SFR) in our Galaxy. The LAT source is located in the G25 region, 1 degrees.7. x. 2 degrees.1 around (l, b) = (25 degrees.0, 0 degrees.0). The gamma-ray emission is found to be composed of two extended sources and one pointlike source. The extended sources have similar sizes of about 1 degrees.4. x. 0 degrees.1. An similar to 0 degrees.4 diameter subregion of one has a photon index of Gamma = 1.53 +/- 0.15, and is spatially coincident with HESS J1837-069, likely a pulsar wind nebula. The other parts of the extended sources have a photon index of Gamma = 2.1 +/- 0.2 without significant spectral curvature. Given their spatial and spectral properties, they have no clear associations with sources at other wavelengths. Their gamma-ray properties are similar to those of the Cygnus cocoon SFR, the only firmly established gamma-ray detection of an SFR in the Galaxy. Indeed, we find bubble-like structures of atomic and molecular gas in G25, which may be created by a putative OB association/cluster. The gamma-ray emitting regions appear confined in the bubble-like structure; similar properties are also found in the Cygnus cocoon. In addition, using observations with the XMM-Newton, we find a candidate young massive OB association/cluster G25.18+0.26 in the G25 region. We propose that the extended gamma-ray emission in G25 is associated with an SFR driven by G25.18+0.26. Based on this scenario, we discuss possible acceleration processes in the SFR and compare them with the Cygnus cocoon.
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APA:
Katsuta, J., Uchiyama, Y., & Funk, S. (2017). Extended Gamma-Ray Emission from the G25.0+0.0 Region: A Star-forming Region Powered by the Newly Found OB Association? Astrophysical Journal, 839(2). https://doi.org/10.3847/1538-4357/aa6aa3
MLA:
Katsuta, J., Y. Uchiyama, and Stefan Funk. "Extended Gamma-Ray Emission from the G25.0+0.0 Region: A Star-forming Region Powered by the Newly Found OB Association?" Astrophysical Journal 839.2 (2017).
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