On the Galactic Halos Rotation by Planck Data

Abstract

As galactic halos are not directly visible, there are many ambiguities regarding their composition and rotational velocity. Though most of the dark matter is non-baryonic, some fraction is, and it can be used to trace the halo rotation. Asymmetries in the CMB towards M31 had been seen in the Planck data and ascribed to the rotational Doppler shift of the M31 halo. Subsequently, the same methods were used in the direction of five other galaxies belonging to the Local Group, namely M33, M81, M82, NGC 5128, and NGC 4594. It had been proved that there could be stable clouds of gas and dust in thermal equilibrium with the CMB at 2.7 K, which had been called “virial clouds”. In this paper, adopting this scenerio, an attempt is made to constrain the fraction of dust grains and gas molecules in the clouds.

Physics news on the Internet (based on electronic preprints)

“…The observation of several galaxies by the WMAP and Planck telescopes actually revealed shifts in the spectra, corresponding to halo rotation. In a new study by N Tahir et al [17], different versions of composition, structure, and distribution of cold baryon clouds in the halo were considered for several galaxies. The results were compared with the data of the Planck space telescope.…”