Distribution of Quasars in the Galaxy
We shall adopt here as a working hypothesis the assumption that planetary
nuclei and quasars are related objects and that their distribution in the
galaxy are not very different. In other words we expect a concentration
of quasars in the galactic plane and a gradual decrease with absolute z
(the distance from the galactic plane). The rate of decrease dlogN/dz is
known to be different for different types of stellar objects, and it is
entirely possible that dlogN/dz for quasars may be much different from that
for planetary nebulae. At present, about 1500 quasars have been identified
(Hewitt and Burbidge, 1980).
All of them, except a few (about 11) have galactic latitudes greater
than 10 deg. We have discussed the reasons for this apparent lack of
quasars in the zone within 10 deg from the galactic plane in a previous paper.
(Varshni, 1977).
As the saying goes, 'Absence of evidence is not evidence of absence'.
No one has carried out any detailed investigation to look for quasars in
the zone near the galactic plane. We may note here that there is no shortage
of faint stellar objects in this zone
(Allen, 1973;
Trumpler et al., 1953).
But no systematic study of their spectra has ever been carried out.
Next Section: The space density of quasars