A different galaxy cluster has galaxies within it whose dispersion in redshift (about their mean redshift) is found from spectroscopic observations to be z. The mean redshift of all the galaxies is z . Observing the locations of the galaxies in this cluster, we find that the half-light radius (the radius that encloses half of all the light from the galaxies in the cluster) subtends an angle of h. What is the estimated mass of this galaxy cluster? Give your response in solar masses, in scientific notation to one decimal place. (You can assume the peculiar velocity of the cluster as a whole is negligible, i.e. the cluster's mean redshift is obtained with the Hubble flow). Hints: As in our video, you can take the geometric factor to be = 0.45. Also, don't miss the factor of 3 between the line-of-sight velocity dispersion and the total velocity dispersion (do you understand where this factor of 3 comes from?). Values: z = 0.1 z = 0.004 h = 13 arcminutes