Extended or point source?

In summary, to determine whether a radio source is a point source or extended source using a single radio telescope, one would need to scan the image over time and observe its size. This method assumes that the source is a constant and is larger than one pixel.
  • #1
mordeth
1
0
If you were using a single radio telescope (not an interferometer) how could you tell whether a radio source was a point source or extended source?

I have searched the internet far and wide for many hours trying to answer this - I know what the difference between a point source and extended source is, but I'm not sure whether the question is asking for a simple or technical explanation. Is it something to do with the radio telescope data or how the radiation from the source is spread out on the dish when its received?
 
Last edited:
Astronomy news on Phys.org
  • #2
I assume you mean the usual in-effect single-pixel radio telescope at a single point in time. Then it is pretty much impossible to tell the difference, I think. The usual method then is to look at different points at different times. i.e. scan out the image over time. You can then detect its size, assuming its pretty much a constant source and really bigger than one pixel.

Jim Graber
 

What is the difference between an extended and point source?

An extended source emits light or other forms of radiation from a relatively large area, while a point source emits from a single location.

How does the size of a source affect its brightness?

Larger sources tend to be brighter than smaller ones because they emit more radiation from a larger area.

Can a point source become an extended source or vice versa?

Yes, this can happen when the distance between the source and the observer changes. A point source can appear as an extended source if it is far enough away, and an extended source can appear as a point source if it is close enough.

What types of sources are considered extended sources?

Extended sources can include galaxies, nebulae, and even stars that are large and bright enough to be resolved by telescopes or other instruments.

How can we determine if a source is extended or point source?

If the source appears as a distinct point of light in the sky, it is most likely a point source. If it appears to have an angular size or shape, it is likely an extended source. Observing the source with different instruments or techniques can also help determine its nature.

Similar threads

  • Astronomy and Astrophysics
2
Replies
56
Views
6K
  • Astronomy and Astrophysics
Replies
6
Views
2K
  • Astronomy and Astrophysics
Replies
15
Views
4K
  • Astronomy and Astrophysics
2
Replies
69
Views
6K
  • Other Physics Topics
Replies
6
Views
2K
  • Astronomy and Astrophysics
Replies
21
Views
1K
  • Astronomy and Astrophysics
Replies
16
Views
6K
Replies
2
Views
2K
  • Astronomy and Astrophysics
Replies
1
Views
1K
Replies
17
Views
5K
Back
Top