Local burst model of CMB temperature fluctuations: luminescence in lines of primary para- and orthohelium

¹ Special Astrophysical Observatory, St. Petersburg Branch, Russian Academy of Sciences, 196140 St. Petersburg, Russia
² Sobolev Astronomical Institute, St. Petersburg State University, Universitetskii pr. 28, 198504 St. Petersburg, Russia
³ Department of Physics, St. Petersburg State University, Petrodvorets, Ulianovskaya 1, 198504 St. Petersburg, Russia
e-mail: zalialiutdinov@gmail.com

Received: 1 June 2018
Accepted: 2 August 2018

Abstract

We have considered the formation of the luminescent subordinate HeI lines by the absorption of continuum radiation from a source in the lines of the main HeI series in the expanding Universe. It is suggested that at some moment of time, corresponding to the redshift z₀, a burst of superequilibrium blackbody radiation with a temperature T + ΔT occurs. This radiation is partially absorbed at different z <  z₀ in the lines of the main HeI series and then converted into the radiation of subordinate lines. If ν_ij is the laboratory frequency of the transition of some subordinate line originating at some z, then in the present time its frequency will be ν = ν_ij/(1 + z). For different z (and, consequently, for different ν), the quantum yield for the subordinate lines of para- and orthohelium - the number of photons emitted in the subordinate line, per one initial excited atom and line profiles are calculated. Different pumping channels were considered. Spatial and angular distributions of radiation intensity of luminescent lines for the spherically symmetric radiation sources are presented. It is shown that for sufficiently large ΔT/T, the luminescent lines can be very noticeable in the spectrum of blackbody background radiation.