| Issue |
A&A
Volume 411, Number 1, November III 2003
Special letters issue on: first science with integral
|
|
|---|---|---|
| Page(s) | L457 - L460 | |
| Section | Letters | |
| DOI | https://doi.org/10.1051/0004-6361:20031437 | |
| Published online | 17 November 2003 | |
Letter to the Editor
Early SPI/INTEGRAL constraints on the morphology of the 511 keV line emission in the 4th galactic quadrant*
1
Centre d'Étude Spatiale des Rayonnements, CNRS/UPS, BP 4346, 31028 Toulouse Cedex 4, France
2
Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
3
IASF, via Bassini 15, 20133 Milano, Italy
4
DSM/DAPNIA/SAp, CEA-Saclay, 91191 Gif-sur-Yvette, France
5
Max-Planck-Institut für Extraterrestrische Physic, Postfach 1603, 85740 Garching, Germany
Corresponding author: J. Knödlseder, knodlseder@cesr.fr
Received:
21
July
2003
Accepted:
16
September
2003
We provide first constraints on the morphology of the 511 keV line
emission from the galactic centre region on basis of data taken with
the spectrometer SPI on the INTEGRAL gamma-ray observatory.
The data suggest an azimuthally symmetric galactic bulge component with
FWHM of ~
with a 
uncertainty range covering
.
The 511 keV line flux in the bulge component amounts to
ph cm-2 s-1.
No evidence for a galactic disk component has been found so far;
upper flux limits in the range 
ph cm-2 s-1 have been obtained that depend on the assumed disk morphology.
These limits correspond to lower limits on the bulge-to-disk ratio
of 
.
Key words: gamma rays: observations
© ESO, 2003
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