Understanding Observing Frequency and Its Significance in Radio Astronomy

In summary, the conversation discusses the concept of a radio telescope and how it is used to observe objects at specific redshifts in the radio band. The term "radio galaxy" is also mentioned, which refers to a galaxy that emits strong radio waves. It is noted that the receiving frequency and distance of a radio galaxy do not necessarily correlate. The conversation also touches on the difference between a radio and x-ray galaxy and the terminology used in astronomy.
  • #1
shirin
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I believe that when we say that this is radio telescope, it means that reciving frequency of it is in radio band. And also it means an observed object by that is in a particular redshift that its emission has a particular frequency that when receives us, is in radio band. Am I right?
For ex. We say cynus A is a radio galaxy. But it doesn't mean that it emits in radio freq. So it doesn't give us any info about physical activities happening in the galaxy, it just tells us about its distance from us.
Sorry for my confusing question! I'm just wondering observing fre just tells us about distance?
 
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  • #2
It is true that "it doesn't mean that its emission has a particular frequency that when receives us, is in radio band." However, the rest of what you say, in particular "it just tells us about its distance from us" seems to be assuming that what we receive as "radio band" is redshifted visible light. That is not in general true.
 
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  • #3
Are all the radio galaxies in the (approximarely) same distance from us? And is the reciveing frequency from all of them in radio band?
I am wondering whether the difference between a radio and x-ray galaxy is their redshift or their emission mechanism ?
 
  • #4
Can you cite where you have seen these terms "radio galaxy" and "x-ray galaxy" and such? I am not familiar with them as standard terminology, but it could be something I haven't heard until now. Also, I think this thread belongs better in the Astronomy and Astrophysics section.
 
  • #5
Oh, you are right! I'm sorry, I was supposed to post them in astronomy section.
Thanks though!
 
  • #6
Matterwave said:
Can you cite where you have seen these terms "radio galaxy"

That is an extremely standard and common term in astronomy
in another thread earlier today I posted an example ... The Centaurus A radio galaxy

Cen_A_multiwavelength_7.jpg
as can be seen, it pumps out masses of EM right across the spectrum

https://en.wikipedia.org/wiki/Cygnus_A

Cygnus A (3C 405) is a radio galaxy, and one of the strongest radio sources in the sky. It was discovered by Grote Reber in 1939. In 1951, Cygnus A, along with Cassiopeia A, and Puppis A were the first "radio stars" identified with an optical source. Of these, Cygnus A became the first radio galaxy; the other two being nebulae inside the Milky Way.[2] In 1953 Roger Jennison and M K Das Gupta showed it to be a double source.[3] Like all radio galaxies, it contains an active galactic nucleus.

Images of the galaxy in the radio portion of the electromagnetic spectrum show two jets protruding in opposite directions from the galaxy's center. These jets extend many times the width of the portion of the host galaxy which emits radiation at visible wavelengths.[4] At the ends of the jets are two lobes with "hot spots" of more intense radiation at their edges. These hot spots are formed when material from the jets collides with the surrounding intergalactic medium.[5]
cheers
Dave
 
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Related to Understanding Observing Frequency and Its Significance in Radio Astronomy

1. What is observing frequency and why is it important in radio astronomy?

Observing frequency refers to the range of electromagnetic waves that a radio telescope is designed to detect. It is important in radio astronomy because different types of celestial objects emit radio waves at specific frequencies, and by studying these frequencies, we can gain insights into their physical properties and processes.

2. How is observing frequency measured and expressed?

Observing frequency is typically measured in Hertz (Hz) or cycles per second, with radio waves falling within the range of 3Hz to 300GHz. In radio astronomy, frequencies are also commonly expressed in units of wavelength, such as centimeters or meters.

3. How does the observing frequency affect the resolution of a radio telescope?

The observing frequency directly affects the resolution of a radio telescope, with higher frequencies providing better resolution. This is because the resolution of a telescope is determined by the size of its dish or aperture in relation to the wavelength of the incoming radio waves. Higher frequencies have shorter wavelengths, allowing for more precise measurements and higher resolution images.

4. Can we observe all frequencies in the electromagnetic spectrum with a radio telescope?

No, radio telescopes are only designed to detect a specific range of frequencies within the electromagnetic spectrum. They are typically limited to detecting radio waves, which have longer wavelengths than other types of electromagnetic radiation such as visible light or X-rays. However, some radio telescopes are equipped with multiple receivers that can detect a wider range of frequencies.

5. How is observing frequency used in the search for extraterrestrial life?

Observing frequency plays a crucial role in the search for extraterrestrial life through the study of radio waves. Scientists use radio telescopes to scan the skies for potential signals from other civilizations, known as the Search for Extraterrestrial Intelligence (SETI). By observing a wide range of frequencies, researchers hope to detect any anomalous signals that may indicate the presence of intelligent life beyond Earth.

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