SPI/INTEGRAL observation of 1809 keV gamma-ray line emission from the Cygnus X region

Abstract

We present first results on the observation of 1809 keV gamma-ray line emission from the Cygnus X region with the SPI imaging spectrometer. Our analysis is based on data from the performance verification phase of the INTEGRAL instruments and comprises 1.3 Ms of exposure time. We observe a 1809 keV line flux of (7.3 +/- 0.9) x 10-5 ph cm-2 s-1 from a region delimited by galactic longitudes 73-93 deg and |b| < 7 deg at a significance level of 8 sigma. The 1809 keV line appears moderately broadened, with an intrinsic FWHM of 3.3 +/- 1.3 keV. Although this broadening is only marginal (at the 2 sigma level our data are compatible with an unbroadened line), it could reflect the 26Al ejecta kinematics.