Question

8. What are the two absorption lines that are distinct in galaxy spectrums and what element causes both? 9. The main objective is to obtain the distance and velocity of several galaxies and plot this data, estimating the age of the universe from Hubble's Law. You will measure the wavelength of a well known spectral line $\lambda_{H_{measured}}$ and subtract the laboratory value $\lambda_{H}$ to see how the line has been shifted by the Doppler effect: $\Delta\lambda_{H} = \lambda_{H_{measured}} - \lambda_{H}$ You can then determine the recessional velocity $v_{H}$ and the distance $d$ in parsecs of the galaxy with: $v_{H} = c \frac{\Delta\lambda_{H}}{\lambda_{H}}$ $d = 10 \cdot 10^{\frac{m-M}{5}}$ a. If $\lambda_{H_{measured}} = 3995.56$ A and the well-known lab value is $\lambda_{H} = 3968.47$ A, what is the recessional velocity $v_{H}$ of the galaxy? Use $c = 3 \times 10^{5}$ km/s for the value of the speed of light. b. If a spectrograph measures an apparent magnitude of $m = 12.0$ and the absolute magnitude of most galaxies is $M = -21$ (note the minus sign), what is the distance d to the galaxy?

          8. What are the two absorption lines that are distinct in galaxy spectrums and what
element causes both?
9. The main objective is to obtain the distance and velocity of several galaxies and plot
this data, estimating the age of the universe from Hubble's Law. You will measure
the wavelength of a well known spectral line $\lambda_{H_{measured}}$ and subtract the laboratory
value $\lambda_{H}$ to see how the line has been shifted by the Doppler effect:
$\Delta\lambda_{H} = \lambda_{H_{measured}} - \lambda_{H}$
You can then determine the recessional velocity $v_{H}$ and the distance $d$ in parsecs of
the galaxy with:
$v_{H} = c \frac{\Delta\lambda_{H}}{\lambda_{H}}$
$d = 10 \cdot 10^{\frac{m-M}{5}}$
a. If $\lambda_{H_{measured}} = 3995.56$ A and the well-known lab value is $\lambda_{H} = 3968.47$ A, what
is the recessional velocity $v_{H}$ of the galaxy? Use $c = 3 \times 10^{5}$ km/s for the value of
the speed of light.
b. If a spectrograph measures an apparent magnitude of $m = 12.0$ and the absolute
magnitude of most galaxies is $M = -21$ (note the minus sign), what is the distance
d to the galaxy?

8. What are the two absorption lines that are distinct in galaxy spectrums and what
element causes both?
9. The main objective is to obtain the distance and velocity of several galaxies and plot
this data, estimating the age of the universe from Hubble's Law. You will measure
the wavelength of a well known spectral line λHmeasured and subtract the laboratory
value λH to see how the line has been shifted by the Doppler effect:
ΔλH = λHmeasured - λH
You can then determine the recessional velocity vH and the distance d in parsecs of
the galaxy with:
vH = c (ΔλH)/(λH)
d = 10 · 10^(m-M)/(5)
a. If λHmeasured = 3995.56 A and the well-known lab value is λH = 3968.47 A, what
is the recessional velocity vH of the galaxy? Use c = 3 × 10^5 km/s for the value of
the speed of light.
b. If a spectrograph measures an apparent magnitude of m = 12.0 and the absolute
magnitude of most galaxies is M = -21 (note the minus sign), what is the distance
d to the galaxy?

Added by Brandon M.

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