Trying to understand the importance of radio pulsars


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Larry
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Message 111224 - Posted 21 Mar 2011 4:55:42 UTC

    Im new to einstine@home and trying to understand the correlation between radio pulsars and gravity waves. Ive been doing seti@home for a long time. From the graphics shown there appears to be a band of pulsars. I dont understand that, why a band and rather tight band at that but massive. Im trying to understand the program goals and their importance. I find it fasinating.

    Profile Mike Hewson
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    Message 111226 - Posted 21 Mar 2011 5:32:13 UTC - in response to Message 111224.

      Last modified: 21 Mar 2011 5:33:32 UTC

      Im new to einstine@home and trying to understand the correlation between radio pulsars and gravity waves. Ive been doing seti@home for a long time. From the graphics shown there appears to be a band of pulsars. I dont understand that, why a band and rather tight band at that but massive. Im trying to understand the program goals and their importance. I find it fasinating.

      Welcome to E@H Larry! Yup it's a fascinating area of investigation for sure. The project is looking at/for some of the most extreme objects in the universe, no less. :-)

      The same group of objects, neutron stars and variants, are responsible for both signal types. Neutron stars are very dense - many sun's worth of mass would fit within the confines of New York City - and have intense electromagnetic properties, thus emitting radio waves. The band in our sky view reflects our relations to the galaxy that we are in. It's pizza shaped, and if you are in the plane or substance of the pizza ( about two thirds of the way out from the pizza centre ) and then look all around you : what you'll see is a lot of pizza toward the centre and less toward the pizza edge. If you look out of the pizza, above and below the platter, not much is evident. So the screensaver graphic shows a dense lot of ( purple? ) dots in the general direction of galactic centre and quite a sparse sprinkling 180 degrees away ( you could think of the neutron stars as your favorite pizza topping, I don't know, err - say anchovies ). You can even see the plane of the galaxy which looks tilted on the graphic on account of Earth's axis of rotation not coinciding with the galaxy's axis of rotation ( or Earth's axis is not perpendicular to the plane of the pizza ).

      Cheers, Mike.
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      "I have made this letter longer than usual, because I lack the time to make it short." - Blaise Pascal

      Larry
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      Message 111242 - Posted 21 Mar 2011 16:58:01 UTC - in response to Message 111226.

        Thank you for your response I do apprecate it. I thank you for your time and patience and helping me understand a little clearer. When these binary systems converge does the white dwarf engulf its neighbor or does it seek equlibrium and a stable orbit that just feeds gases and plama and create the radio pulsing.
        Seems the pulsars are everwhere towards the galactic center. So much we dont understand.

        Profile Mike Hewson
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        Message 111244 - Posted 22 Mar 2011 1:59:25 UTC - in response to Message 111242.

          Thank you for your response I do apprecate it. I thank you for your time and patience and helping me understand a little clearer. When these binary systems converge does the white dwarf engulf its neighbor or does it seek equlibrium and a stable orbit that just feeds gases and plama and create the radio pulsing.
          Seems the pulsars are everwhere towards the galactic center. So much we dont understand.

          The white dwarf is not the one producing the pulses. Think of a neutron star as nearly a black hole, where matter is squeezed so tight together that atoms per se don't exist - any protons and electrons have formed into neutrons, and the normal atomic widths ( most of an atom is empty ) don't apply. It's a gigantic nucleus, but if not alot more mass is added to it then you get the pinching off of spacetime that a black hole surface represents. A white dwarf still has atoms as separate entities and the repulsion between electrons holds atoms apart.

          Now many of these neutron stars are in company, as are most stars really ( our Sun as a solo operator is in the minority ). Frequently the company is indeed a larger beast which as you say can transfer mass to the smaller companion. Many variants exist here on how these systems evolve. Binary pulsars are one type of end game - two pulsars orbiting each other - and these are of great interest here at E@H. We don't actually know the precise mechanisms of why a beam of radiation is produced. We know why the pulsing occurs - the beam sweeps past our direction like a lighthouse - but the mechanism of beam generation is rather a mystery, apart from general ideas like a dynamo.

          Cheers, Mike.
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          Profile Matt Giwer
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          Message 111283 - Posted 23 Mar 2011 23:12:33 UTC - in response to Message 111224.

            Im new to einstine@home and trying to understand the correlation between radio pulsars and gravity waves. Ive been doing seti@home for a long time. From the graphics shown there appears to be a band of pulsars. I dont understand that, why a band and rather tight band at that but massive. Im trying to understand the program goals and their importance. I find it fasinating.


            I'm not sure what graphs you are talking about but there is a magic size around 1.4 solar masses that automatically results in a neutron star. Bigger you get a black hole, smaller a white dwarf. Because of black holes larger things disappear while there is a smooth range of white dwarves so a large population of neutron stars is an artefact of the distribution.

            I give a reference to Gravity from the Ground Up post in this forum which has a nicely wordy discussion of the subject with simplified math.

            If that is what you mean by what you see in the graphics that might address your question.

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            Message boards : Science : Trying to understand the importance of radio pulsars


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            This material is based upon work supported by the National Science Foundation (NSF) under Grants PHY-1104902, PHY-1104617 and PHY-1105572 and by the Max Planck Gesellschaft (MPG). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the investigators and do not necessarily reflect the views of the NSF or the MPG.

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