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RESEARCH PRODUCT

A Preliminary BeppoSAX Study of the (Bright) Atoll Source GX 9+1

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We report the preliminary results of a 350 ks BeppoSAX observation of the bright atoll source GX 9+1. In the field of view of the MECS instrument we discovered a X-ray pulsar, designated SAX J1802.7 - 2017, at an angular distance from GX 9+1 of ∼ 22 ′ . Since the X-ray emission of SAX J1802.7 - 2017 contaminates the energy spectrum above 10 keV we studied the energy spectrum of GX 9+1 in the energy band 0.1 - 10keV. We selected four regions in the color-color diagram and extracted one spectrum from each region. A bump below 1keV is present in the spectra using a model composed by a Comptonized component absorbed by neutral matter having an equivalent hydrogen column of 1.5 x 10 22 cm -2 . The bump disappears adding an overabundance of iron and nickel of 7 and 70 with respect to the solar iron abundance and to the solar nickel abundance, moreover the equivalent hydrogen column becames 0.5 x 10 22 cm -2 suggesting a possible distance to the source of 4.5 kpc, implying a luminosity of 4 x 10 37 ergs -1 and that the bright atoll source GX 9+1 is not bright but it is a typical atoll source.