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9. The Hubble Law and Standard Candles. An elliptical galaxy called A lies at a distance of 20 Mpc (megaparsecs). What would the velocity inferred from the redshift of its spectral lines be for galaxy A? Assume a Hubble constant of 73 km/s/Mpc. An identical elliptical galaxy called B with exactly the same luminosity as A is found to have a redshift exactly three times that of A. How does the measured brightness of B compare to that of A? (In other words, what is the ratio BB/BA?) c. Suppose a Type I (white dwarf) supernova explodes in galaxy B and has a maximum luminosity of 5 x 10^45 W. If the brightness of the supernova is measured to be 1 x 10^-4 W/m^2, determine the distance to Galaxy B in pc and explain whether its distance is what you expect assuming a 10% error in the observations.

          9. The Hubble Law and Standard Candles. An elliptical galaxy called A lies at a distance of 20 Mpc (megaparsecs). What would the velocity inferred from the redshift of its spectral lines be for galaxy A? Assume a Hubble constant of 73 km/s/Mpc.
An identical elliptical galaxy called B with exactly the same luminosity as A is found to have a redshift exactly three times that of A. How does the measured brightness of B compare to that of A? (In other words, what is the ratio BB/BA?)
c. Suppose a Type I (white dwarf) supernova explodes in galaxy B and has a maximum luminosity of 5 x 10^45 W. If the brightness of the supernova is measured to be 1 x 10^-4 W/m^2, determine the distance to Galaxy B in pc and explain whether its distance is what you expect assuming a 10% error in the observations.

Added by Pablo S.

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