Non-thermal Sunyaev-Zeldovich signal from radio galaxy cocoons
(2020)cite arxiv:2009.03440Comment: Comments welcome.Аннотация
Energetic electrons in the cocoons of radio galaxies make them potential
sources for not only radio and X-rays but also Sunyaev-Zeldovich (SZ)
distortions in the cosmic microwave background (CMB) radiation. Previous works
have discussed the energetics of radio galaxy cocoons, but assuming thermal SZ
effect, coming from the non-thermal electron population. We use an improved
evolutionary model for radio galaxy cocoons to estimate the observed parameters
such as the radio luminosities and intensity of SZ-distortions at the redshifts
of observation. We, further, quantify the the effects of various relevant
physical parameters of the radio galaxies, such as the jet power, the time
scale over which the jet is active, the evolutionary time scale for the cocoon,
etc on the observed parameters. For current SZ observations towards galaxy
clusters, we find that the non-thermal SZ distortions from radio cocoons
embedded in galaxy clusters can be non-negligible compared to the amount of
thermal SZ distortion from the intra-cluster medium and, hence, can not be
neglected. We show that small and young (and preferably residing in a cluster
environment) radio galaxies offer better prospects for the detection of the
non-thermal SZ signal from these sources. We further discuss the limits on
different physical parameters for some sources for which SZ effect has been
either detected or upper limits are available. The evolutionary models enable
us to obtain limits, previously unavailable, on the low energy cut-off of
electron spectrum ($p_min 1--2$) in order to explain the recent
non-thermal SZ detection MDCMSNW2017. Finally, we discuss how future
CMB experiments, which would cover higher frequency bands ($>$400 GHz), may
provide clear signatures for non-thermal SZ effect.
Описание
Non-thermal Sunyaev-Zeldovich signal from radio galaxy cocoons