by Ann » Mon Mar 11, 2019 6:08 am
APOD Robot wrote:
Featured here, HAWC+ observations of the M82, the Cigar galaxy, show that the central magnetic field is perpendicular to the disk and parallel to the strong supergalactic wind. This observation bolsters the hypothesis that M82's central magnetic field helps its wind transport the mass of millions of stars out from the central star-burst region.
The central magnetic field of the Cigar galaxy.
NASA, SOFIA, E. Lopez-Rodriguez; NASA, Spitzer, J. Moustakas et al
Inner disk and jet of M87.
Holland Ford, Space Telescope Science Institute/Johns Hopkins University; Richard Harms,
Applied Research Corp.; Zlatan Tsvetanov, Arthur Davidsen, and Gerard Kriss
at Johns Hopkins; Ralph Bohlin and George Hartig at Space Telescope
Science Institute; Linda Dressel and Ajay K.Kochhar at Applied Research Corp.
in Landover, Md.; and Bruce Margon fromthe University of Washington in Seattle NASA/ESA
Interesting. Isn't that how jets from supermassive black holes get going?
Ars Technica wrote:
At the centers of some massive galaxies, supermassive black holes power incredibly bright objects called quasars. Black holes gobble up matter so quickly that the infalling matter heats up from friction and emits light. While this disk of accreting matter is incredibly bright on its own, the black hole has another source of light: jets erupt from the poles of the black hole, shooting particles at speeds approaching that of light. These jets are incredibly bright—possibly brighter than the accretion disk.
It’s not known for sure what causes the jets. It’s thought that the black hole’s spin and mass interact with the magnetic field near the black hole to accelerate the particles. While some evidence supports this model, it's been difficult to test, mainly because scientists lacked a full knowledge of how bright the accretion disks is. But a new study of a sample of blazars (quasars with jets that point toward Earth) shows a clear correlation between the jets' power and the accretion disk’s brightness. This suggests that the magnetic field is a factor in producing the jets.
But in the case of M82, it seems to be the wind from the extreme starburst at the center of the galaxy that powers both the magnetism and the outflow of gas. That may be why the outflow from M82 is relatively "broad", and not long and narrow, as seems to be the case of black hole-powered jets.
Ann
[quote]APOD Robot wrote:
Featured here, HAWC+ observations of the M82, the Cigar galaxy, show that the central magnetic field is perpendicular to the disk and parallel to the strong supergalactic wind. This observation bolsters the hypothesis that M82's central magnetic field helps its wind transport the mass of millions of stars out from the central star-burst region.[/quote]
[float=left][img2]https://imagecache.jpl.nasa.gov/images/640x350/PIA23010-16-640x350.jpg[/img2][c][size=75]The central magnetic field of the Cigar galaxy.
NASA, SOFIA, E. Lopez-Rodriguez; NASA, Spitzer, J. Moustakas et al[/size][/c][/float] [float=right][img2]http://www.physics.usyd.edu.au/sifa/rcfta/anrep96/anrep96/m87.gif[/img2][c][size=85]Inner disk and jet of M87.
[size=85]Holland Ford, Space Telescope Science Institute/Johns Hopkins University; Richard Harms,
Applied Research Corp.; Zlatan Tsvetanov, Arthur Davidsen, and Gerard Kriss
at Johns Hopkins; Ralph Bohlin and George Hartig at Space Telescope
Science Institute; Linda Dressel and Ajay K.Kochhar at Applied Research Corp.
in Landover, Md.; and Bruce Margon fromthe University of Washington in Seattle NASA/ESA[/size][/c][/size][/float]
Interesting. Isn't that how jets from supermassive black holes get going?
[quote][url=https://arstechnica.com/science/2014/11/black-hole-jets-how-do-they-work-magnets/]Ars Technica[/url] wrote:
At the centers of some massive galaxies, supermassive black holes power incredibly bright objects called quasars. Black holes gobble up matter so quickly that the infalling matter heats up from friction and emits light. While this disk of accreting matter is incredibly bright on its own, the black hole has another source of light: jets erupt from the poles of the black hole, shooting particles at speeds approaching that of light. These jets are incredibly bright—possibly brighter than the accretion disk.
It’s not known for sure what causes the jets. It’s thought that the black hole’s spin and mass interact with the magnetic field near the black hole to accelerate the particles. While some evidence supports this model, it's been difficult to test, mainly because scientists lacked a full knowledge of how bright the accretion disks is. But a new study of a sample of blazars (quasars with jets that point toward Earth) shows a clear correlation between the jets' power and the accretion disk’s brightness. This suggests that the magnetic field is a factor in producing the jets.[/quote]
But in the case of M82, it seems to be the wind from the extreme starburst at the center of the galaxy that powers both the magnetism and the outflow of gas. That may be why the outflow from M82 is relatively "broad", and not long and narrow, as seems to be the case of black hole-powered jets.
Ann