Here we say that F is the flux (also known as the observed or apparent brightness), measured in watts/m 2 ; L is the luminosity (also called the intrinsic brightness), measured in watts; and \...Here we say that F is the flux (also known as the observed or apparent brightness), measured in watts/m 2 ; L is the luminosity (also called the intrinsic brightness), measured in watts; and d is the distance to the object, measured in meters. If a galaxy is rotating, the gas in the part of the galaxy rotating toward us will show a blueshift, while the gas in the part of the galaxy rotating away from us will show a redshift.
