For around forty years, astrophysicists have observed the annihilation of positrons in the Galaxy at a prodigious rate. ... The fact the Galactic bulge far outshines the disk in annihilating positrons which are injected into the ISM at low energies makes the source of the positrons difficult to identify, as the main source of such positrons are prima facie located in the Galactic disk. ...

... Printed in U.S.A. THE STELLAR DISK THICKNESS OF LOW SURFACE BRIGHTNESS GALAXIES D. Bizyaev 1,2,3 and S. Kajsin 4 Received 2003 October 23; accepted 2004 June 9 ABSTRACT We present surface photometry results for a sample of 11 edge-on galaxies observed with the 6 m telescope at the Special Astrophysical Observatory, Russia. ... We find from a comparison of photometric scales that the stellar disks of LSB galaxies are thinner than those of high surface brightness ( HSB) galaxies. ... UGC 11301 .. ...