Recent observations on cosmic electrons and their consequences on different cosmic ray models and related astrophysical quantities

Abstract

An experiment has been carried out to study the electron component of the primary cosmic radiation at energies >12 GeV using a hypersensitised nuclear emulsion stack, flown oriented in the east-west plane over Hyderabad, India. The results of this experiment, on the basis of 28 identified electrons of energy above 12 GeV are: (i) the integral flux of electrons above an effective energy of 16 GeV is 0·51±·10 per m.² sec. sr.; (ii) the differential energy spectrum between 12 and 300 GeV can be represented as N(E)dE=12·7 E^-2.1±·2 dE m.^-2 sec.^-1 sr.^-1; and (iii) the fraction of positrons among the total electrons in the energy region 12 to 30 GeV has been discussed. A critical study has been made on the applicability of different cosmic ray models by making use of the observed differential energy spectrum of electrons and the relevant astrophysical parameters associated with the confinement regions. The confinement regions considered are: (i) the universe as a whole, (ii) the super cluster to which our galaxy belongs, (iii) the galactic halo and (iv) the galactic disc. The consequences of the recently postulated universal black body radiation at 3° K. on the cosmic ray models have also been considered. Some of the crucial experiments needed to set more stringent constrains on the models which would then permit meaningful interpretation, are enumerated.