Another standard candle can be RR lyraes. A standard candle can be described as the astronomical object that has a calculated and absolute magnitude. The standard candles are important because they act as reference to the other objects for which the astronomers need to measure the distance. The absolute magnitude of standard candles is determined by the variability period.
Doppler effect involves movement of waves and how we perceive them. In our daily life, there are several instances that are an example of doppler effect due to travelling of the sound waves, for instance, when we hear an ambulance waiting on the stoplight, we hear it differently when it is speeding towards the car, and when it has sped away or ahead of the car. Its pitch changes and the wave distance changes as well. This is a classical example of Doppler effect.
To calculate the red shift of galaxy, we have:
- Z = ?
- V = speed of galaxy = 3% of the speed of light = 8993773.74 m/s
- C = speed of light = 299 792 458 m/s
Now we have:
Z = v/c = 0.03
The redshift will be 0.03.
- For calculating redshift, we have:
Z = 589-552 / 552
Z = 0.067 (redshift)
Madau, P., Ferguson, H. C., Dickinson, M. E., Giavalisco, M., Steidel, C. C., & Fruchter, A. (1996). High-redshift galaxies in the Hubble Deep Field: colour selection and star formation history to z∼ 4. Monthly Notices of the Royal Astronomical Society, 283(4), 1388-1404.
Cohen, J. G., Hogg, D. W., Blandford, R., Cowie, L. L., Hu, E., Songaila, A., … & Richberg, K. (2000). Caltech faint galaxy redshift survey. X. A redshift survey in the region of the Hubble deep field north. The Astrophysical Journal, 538(1), 29.
Arnouts, S., Cristiani, S., Moscardini, L., Matarrese, S., Lucchin, F., Fontana, A., & Giallongo, E. (1999). Measuring and modelling the redshift evolution of clustering: the Hubble Deep Field North. Monthly Notices of the Royal Astronomical Society, 310(2), 540-556.