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Observation frequency

  1. Oct 9, 2015 #1
    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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  3. Oct 10, 2015 #2


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    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.
  4. Oct 10, 2015 #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?
  5. Oct 10, 2015 #4


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    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


  6. Oct 10, 2015 #5
    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 recieved frequency to us, then what does distinguish it as a "radio" galaxy?
  7. Oct 11, 2015 #6


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    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'.
  8. Oct 11, 2015 #7


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