7/18/2019 Newly Found Pulsar Helps Astronomers Explore Milky Way
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Newly Found Pulsar Helps Astronomers Explore Milky Way'sMysterious CorePosted by Guy Pirro on 12/22/2013 3:33 PM
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Astronomers have made an important measurement of the magnetic field emanating from a swirling diskof material surrounding the black hole at the center of our Milky Way Galay. !he measurement" madeby observing a recently discovered pulsar" is providing them with a powerful new tool for studying themysterious region at the core of our home galay.
#ike most galaies" the Milky Way harbors a supermassive black hole at its center" some $%"000 lightyears from &arth. !he Milky Way's central black hole is some four million times more massive than the
(un. )lack holes" concentrations of mass so dense that not even light can escape them" can pull inmaterial from their surroundings. !hat material usually forms a swirling disk around the black hole" withmaterial falling from the outer portion of the disk inward until it is sucked into the black hole itself.
In this artist's conception, the magnetic fied from a rotating dis! surrounding the supermassi"e bac! hoe
at the center of the Mi!y #ay e$tends out%ard to encompass the cosest pusar yet found to the Gaa$y's
core& he pusar has a strong magnetic fied, and emits ighthouse(i!e beams of radio %a"es out%ard from
the poes of its o%n magnetic fied& hose beams are detected and anay)ed by radio teescopes on *arth&+Image redit: -i .a$ton, /I/.45
7/18/2019 Newly Found Pulsar Helps Astronomers Explore Milky Way
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(uch disks concentrate not only the matter pulled into them but also the magnetic fields associated withthat matter" forming a giant" twisting magnetic field that is thought to propel some of the matter backoutward along its poles in superfast *+ets.*
!he region near the black hole is obscured from visible,light observations by gas and dust" and is aneotic" etreme environment still little,understood by astronomers. !he magnetic field in the centralportion of the region is an important component that affects other phenomena.
!he first link to measuring the magnetic field near the black hole came last April when -A(A's (wiftsatellite detected a flare of ,rays from near the Milky Way's center. /bservers soon determined that the,rays were coming in regular pulses. ollow,on observations with radio telescopes" including ones inGermany" rance" and the -ational (cience oundation's 1arl G. 2ansky 3ery #arge Array 43#A5" showedradio pulses identically spaced. !he astronomers concluded the ob+ect" called 6(7 289:;,$<00" is amagnetar" a highly,magneti=ed pulsar" or spinning neutron star.
!he pulsar is the closest yet found to the black hole" possibly within less than half a light,year. Analysisof the radio waves coming from the pulsar showed that they are undergoing a dramatic twist as theytravel from the pulsar to &arth. (uch a twist" called araday rotation" comes when the waves travelthrough charged gas that is within a magnetic field.
!he charged gas" the astronomers said" is somewhere roughly 8;0 light,years from the black hole"directly between the pulsar and &arth. Measuring the twist in the waves caused by their passage throughthis gas allowed the scientists to calculate the strength of the magnetic field. !he magnetic field is acrucial part of the black hole's environment" affecting the structure of the flow of material into the blackhole" and even regulating that flow.
*!he lucky alignment of this gas with a pulsar so close to the black hole has given us a valuable tool forunderstanding this difficult,to,observe environment"* said 6aul >emorest" of the -ational 7adioAstronomy /bservatory.
!he measured strength of the magnetic field at the presumed distance of the gas cloud from the blackhole is about what astronomers epected" based on the intensity of ,rays and radio waves coming fromthe area closest to the black hole. !he measurements also indicate that the field is relatively well,ordered" instead of turbulent" the scientists said.
*!he closer you get to the black hole and the disk surrounding it" the stronger the magnetic field shouldbecome"* >emorest said. */ur measurement shows the field strength we would epect at the distance webelieve that gas cloud is from the black hole"* he added.
!he scientists plan to continue watching 6(7 289:;,$<00" because they epect to detect changes as itmoves in its orbital motion around the black hole. !his will provide additional measurements of themagnetic,field strength in different gas clouds. Also" they epect ,, and hope ,, to find more pulsars thatwill allow them to use the same techni?ue to make a detailed map of the magnetic field near the blackhole.
or more information@
[email protected]$08Bmagfieldcaption
