View Full Version : Discussion: Quasar Image Revises Theories ...
2005-Jun-01, 05:28 PM
SUMMARY: Researchers using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope found something unusual about the jet of material streaming away from a powerful quasar that may leave theorists scratching their heads. Quasars are thought to be jets blasting away from supermassive black holes at the hearts of distant galaxies. The team was expecting magnetic forces to twist the jet and keep material aligned in the middle, but they found just the opposite; the jet is scattered in the centre and more aligned at its edges.
View full article (http://www.universetoday.com/am/publish/quasar_image_jets.html)
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2005-Jun-01, 05:57 PM
Another possibility is that the twisted magnetic effect is important near the edges of the beam, but is swamped in the core of the beam by other effects yet to be determined. I don't know if the SKA will be able to resolve this jet any better, but it will be able to collect information about it much more quickly. Adding a few dishes in Earth-leading and Earth trailing solar orbits will help that resolution quite a bit. The potential for interesting science here is very big.
2005-Jun-02, 02:18 AM
But what other effects could yield the acceleration of particles to this magnitude? The list should be quite short, I would imagine. If I understood how a magnetic field polarized the particle stream in the first place, then I might understand the findings better.
2005-Jun-02, 10:50 AM
This story really strikes a chord with me - particularly with my approach (and that of many others) to science in general.
Time and again we (mainly alternate thinkers - typically non-scientists) come up with ideas to explain phenomena and post them here or elsewhere.
Then Anton or Nereid or some other boffin comes along and points out that our ideas are based on current speculative data and are not good science. Good science is obtained through analysis of observational results - how right they are !!
I will still continue to look at the current understanding of the cosmos and speculate - it's fun - but as this case so aptly proves observation and patient analysis are better science than what sometimes tantamounts to wild guesses!!
2005-Jun-02, 11:27 AM
I agree with your sentiments, Mild mannered.
The origin of the jets of material streaming away from stars and more exotic objects is, in my opinion, one of the most exciting frontiers of astrophysics.
I.e., this is a puzzle I often ponder because I suspect it contains a record of major energy sources in the universe.
However, this uncommonly interesting study has a rather common finding:
"We did find the evidence we were looking for, but we also found an additional piece of evidence that seems to contradict it," said Robert Zavala, an astronomer at the U.S. Naval Observatory's Flagstaff, Arizona, station.
With kind regards,
2005-Jun-02, 01:14 PM
SMBH, quasars, accretion disks, particle accelerators in the sky that make CERN's LHC a game of marbles in comparison, ... it sure is an exciting time!
Lest we all leap straight from one (good) observation to conclude that all of mainstream astrophysics needs a complete re-write, shall we remind ourselves of a tiny phrase in the PR?
or its effects are washed out by interactions between the jet and the interstellar medium that it is drilling through
IOW, what we may be seeing may not be an SMBH with a nice, clean accretion disk sitting in perfectly empty space ... there may be enough 'smog' around to make the deadliest London 'pea-souper' seem like a perfect night on Paranal.
2005-Jul-06, 05:08 AM
I thaought that a Quasar was a star not the center of a galaxy.
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