Open AccessThe discovery of a new non‐thermal X‐ray filament near the Galactic Centre
Author(s) -
Sakano M.,
Warwick R. S.,
Decourchelle A.,
Predehl P.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06299.x
Subject(s) - physics , astrophysics , molecular cloud , luminosity , protein filament , galactic center , astronomy , x ray , flux (metallurgy) , synchrotron radiation , synchrotron , galaxy , stars , optics , materials science , biology , metallurgy , genetics
We report the discovery by XMM–Newton and Chandra of a hard extended X‐ray source (XMM J174540−2904.5) associated with a compact non‐thermal radio filament (the Sgr A–E ‘wisp’= 1LC 359.888−0.086 = G359.88−0.07), which is located within ∼4 arcmin of the Galactic Centre. The source position is also coincident with the peak of the molecular cloud M−0.13−0.08 (the ‘ 20 km s −1 ’ cloud). The X‐ray spectrum is non‐thermal with an energy index of 1.0 + 1.1 − 0.9and a column density of 38 + 7 − 11× 10 22 H cm −2 . The observed 2–10 keV flux of 4 × 10 −13 erg s −1 cm −2 converts to an unabsorbed X‐ray luminosity of 1 × 10 34 erg s −1 assuming a distance of 8.0 kpc. The high column density strongly suggests that this source is located in or behind the Galactic Centre region. Taking account of the broad‐band spectrum, as well as the source morphology and the positional coincidence with a molecular cloud, we conclude that both the radio and X‐ray emission are the result of synchrotron radiation. This is the first time that a filamentary structure in the Galactic Centre region has been shown, unequivocally, to have a non‐thermal X‐ray spectrum.