We report the discovery of an unusual source of extended X-ray emission CXOU J184846.3–013040 ( ‘ The Stem ’ ) located on the outskirts of the globular cluster GLIMPSE-C01 .
No point-like source falls within the extended emission which has an X-ray luminosity L _ { X } ( 0.3–8 keV ) \sim 10 ^ { 32 } ergs s ^ { -1 } and a physical size of \sim 0.1 pc at the inferred distance to the cluster .
These X-ray properties are consistent with the pulsar wind nebula ( PWN ) of an unseen pulsar located within the 95-percent confidence error contour of unidentified Fermi \gamma -ray source 0FGL J1848.6–0138 .
However , we can not exclude an alternative interpretation that postulates X-ray emission associated with a bow shock produced from the interaction of the globular cluster and interstellar gas in the Galactic plane .
Analysis of the X-ray data reveals that ‘ The Stem ’ is most significant in the 2–5 keV band , which suggests that the emission may be dominated by non-thermal bremsstrahlung from suprathermal electrons at the bow shock .
If the bow shock interpretation is correct , these observations would provide compelling evidence that GLIMPSE-C01 is shedding its intracluster gas during a galactic passage .
Such a direct detection of gas stripping would help clarify a crucial step in the evolutionary history of globular clusters .
Intriguingly , the data may also accommodate a new type of X-ray source .