Comparing Radio and X-Ray Galaxies: Redshift vs. Emission Mechanism

In summary, radio galaxies emit significantly more radiation in the radio frequency band compared to other galaxies. They are typically observed to have a redshift that is a factor of 10 greater than "nearby" galaxies. The difference between radio and x-ray galaxies is much larger, with radio galaxies emitting approximately 100000000000 times more radiation in the radio band. Observations of these galaxies are corrected for redshift. The term "radio galaxy" refers to the intense emission of radiation in the RF, visible, and x-ray bands, with Centaurus A being a classic example. Other bands may also show synchrotron activity, but the RF band is the most common for observing this phenomenon.
  • #1
shirin
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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 ?
 
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  • #2
shirin said:
Are all the radio galaxies in the (approximarely) same distance from us?
No, but the difference between "nearby" and "extremely far away" is just a factor of 10 in redshift. The difference between radio and xrays is something like a factor of 100000000000. Also, the observations get corrected for redshift for obvious reasons.
 
  • #3
When we say a galaxy is a radio-galaxy, does it mean that its reciving frequency is in radio band?
Is it correct that all of observibg synchrotron activities are in radio band? Or we can observe this activity in other bands too?
 
  • #4
shirin said:
When we say a galaxy is a radio-galaxy, does it mean that its receiving frequency is in radio band?

no, the opposite ... its an intense emitter of RF, visible and X-rays
Centaurus A radio galaxy is a classic object

here's a set of images showing the galaxy at different wavelengths

Cen_A_multiwavelength_7.jpg
Dave
 
  • #5
davenn said:
no, the opposite ... its an intense emitter of RF, visible and X-rays
Centaurus A radio galaxy is a classic object

here's a set of images showing the galaxy at different wavelengths

View attachment 89998Dave

So I don't understand what categorizes a galaxy as a "radio galaxy". If it has radiation in other bands too and it is not its received frequency to us, then what does distinguish it as a "radio" galaxy?
 
  • #6
shirin said:
So I don't understand what categorizes a galaxy as a "radio galaxy". If it has radiation in other bands too and it is not its received frequency to us, then what does distinguish it as a "radio" galaxy?

Radio galaxies emit large amounts of radiation in the RF band of the EM spectrum. Much more than the usual galaxy does. I think davenn misunderstood what you mean by 'receiving frequency'.
 
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  • #7
Drakkith said:
I think davenn misunderstood what you mean by 'receiving frequency'.

hahaha uh huh
for the first part of my answer yes I did mis-read ... put it down to being exhausted
 

Related to Comparing Radio and X-Ray Galaxies: Redshift vs. Emission Mechanism

1. What is the main difference between radio and X-ray galaxies?

The main difference between radio and X-ray galaxies is the type of electromagnetic radiation they emit. Radio galaxies primarily emit long-wavelength radio waves, while X-ray galaxies emit short-wavelength X-rays.

2. How are redshift measurements used in comparing radio and X-ray galaxies?

Redshift measurements are used to determine the distance of a galaxy from Earth. By comparing the redshift of a radio galaxy to that of an X-ray galaxy, scientists can determine the relative distances between the two and study their properties.

3. What is the primary emission mechanism in radio galaxies?

The primary emission mechanism in radio galaxies is synchrotron radiation. This occurs when high-speed electrons spiral around magnetic field lines, producing radio waves as they decelerate.

4. How do X-ray galaxies differ from active galactic nuclei (AGN)?

X-ray galaxies differ from AGN in that they do not have a supermassive black hole at their center. AGN are powered by the accretion of matter onto a black hole, while X-ray galaxies are powered by other mechanisms such as hot gas emission.

5. What can the comparison between radio and X-ray galaxies tell us about galaxy evolution?

The comparison between radio and X-ray galaxies can provide insight into the evolution of galaxies. For example, the presence or absence of AGN in X-ray galaxies can indicate the stage of a galaxy's evolution, and the presence of extended radio emission can indicate recent interactions or mergers.

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