| Issue |
A&A
Volume 407, Number 3, September I 2003
|
|
|---|---|---|
| Page(s) | L55 - L58 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361:20031056 | |
| Published online | 17 November 2003 | |
Letter to the Editor
Early SPI/INTEGRAL measurements of 511 keV line emission from the 4th quadrant of the Galaxy*
1
CESR, CNRS/UPS, BP 4346, 31028 Toulouse Cedex 4, France
2
LHEA, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
3
DSM/DAPNIA/SAp, CEA-Saclay, 91191 Gif-sur-Yvette, France
4
IFC, CNR “G. Occhialini”, Via Bassini 15, 20133 Milan, Italy
5
MPI für Extraterrestrische Physik, Postfach 1603, 85740 Garching, Germany
6
CASS, UCSD, La Jolla, CA 92093, USA
7
IAS, CNR, Via del Fosso de Cavaliere, 00133 Roma, Italy
8
ESA-ESTEC, RSSD, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
Corresponding author: Pierre Jean, jean@cesr.fr
Received:
11
June
2003
Accepted:
3
July
2003
We report the first measurements of the 511 keV line
emission from the Galactic Centre (GC) region performed with the
spectrometer SPI on the space observatory INTEGRAL
(International Gamma-Ray Astrophysics Laboratory). Taking into account the
range of spatial distribution models which are consistent with the
data, we derive a flux of 
ph cm-2 s-1 and an intrinsic line width of
keV (FWHM). The results are consistent with
other high-spectroscopy measurements, though the width is found to
be at the upper bound of previously reported values.
Key words: gamma rays: observations / line: profiles / Galaxy: center
© ESO, 2003
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