Relativistic Doppler Shift vs Relativistic Beaming

#college #science #physics

In the literature, we notice that Relativistic Doppler Shift is often confused with the Relativistic Beaming, or vice versa. As introduced in this paper, Doppler effect explains the frequency shift of the observed photons, whereas the Relativistic Beaming explains the change in the light intensity, due to the motion of the source with respect to the observer. Following the recent release of the very first picture of a supermassive black hole which is at the heart of M87 Galaxy (where we see the light coming from the accretion disc surrounding the black hole), the immense number of people kept referring to Relativistic Doppler Shift while explaining the light intensity deviations on different parts of the accretion disc. But, those who read this paper will learn that the underlying effect is actually called Relativistic Beaming; the parts on the accretion disc moving toward us seem brighter than the parts moving away from us due to the change in the light intensity, not in the photon frequency.

HERE IS THE FULL PAPER for you to download to your computer.