QSO J1422 is a distant active quasar. NGC 1275 is a massive giant elliptical galaxy in the Perseus cluster. The table below shows some optical and distance data for these two astronomical objects.
| Absolute magnitude | Apparent magnitude | Distance / Mpc\text{Mpc}Mpc | |
|---|---|---|---|
| quasar QSO J1422 | YYY | 13.6 | 1200 |
| galaxy NGC 1275 | -21.8 | 12.6 | 75.0 |
Quasars were initially identified through observations in a specific region of the electromagnetic spectrum. State the property or emission characteristic of early quasars that led to their discovery.
Show that the absolute magnitude Y Y\,Y of quasar QSO J1422 is approximately -27.
Assume that the quasar and the galaxy are both viewed from the same distance. Explain which would be the brighter object, and calculate the ratio:
brightness of brighter objectbrightness of dimmer object \frac{\text{brightness of brighter object}}{\text{brightness of dimmer object}} brightness of dimmer objectbrightness of brighter objectThe supermassive black hole at the centre of NGC 1275 has a mass of 2.4×109 MS2.4 \times 10^9\ M_S2.4×109 MS, where MS=1.99×1030 kgM_S = 1.99 \times 10^{30}\text{ kg}MS=1.99×1030 kg is the mass of the Sun. Calculate the average density within the event horizon of this black hole. (Take G=6.67×10−11 m3 kg−1 s−2G = 6.67 \times 10^{-11}\text{ m}^3\text{ kg}^{-1}\text{ s}^{-2}G=6.67×10−11 m3 kg−1 s−2 and c=3.00×108 m s−1c = 3.00 \times 10^8\text{ m s}^{-1}c=3.00×108 m s−1)
