Question

The 2.3GHz feed at Arecibo illuminates an elliptical aperture 225m by 200m in size, and the aperture efficiency nA over this ellipse is nA about 0.70. What is the sensitivity of this system in K/Jy?

Answer 1

Answer on Question 55056, Physics / Astronomy | Astrophysics

Question:

The 2.3GHz feed at Arecibo illuminates an elliptical aperture 225m by 200m in size, and the aperture efficiency nA over this ellipse is nA about 0.70. What is the sensitivity of this system in K/Jy?

Solution:

The geometric area of the ellipse illuminated is $A_{\text{geom}} = \pi \text{AB}$, where A and B are the semi-major and semi-minor axes (i.e. 225/2m and 200/2 m, respectively). Therefore:

$$A_{\text{geom}} = 3.53 \times 10^{8} \ \text{cm}^{-2}$$

Since the aperture efficiency is:

$$\eta_{A} = \frac{\max(A_{e})}{A_{\text{geom}}},$$ $$A_{e} \leq 2.47 \times 10^{8} \ \text{cm}^{-2}$$

Following part (a), the sensitivity in K/Jy will be:

$$\frac{A_{e}}{2k} = 8.9\,K/\text{Jy}$$

Answer: 8.9 K/Jy

https://www.AssignmentExpert.com