|
Posted on 01/10/2005 1:30:09 PM PST by PatrickHenry
An international team of astronomers has discovered within the heart of a nearby spiral galaxy a quasar whose light spectrum indicates that it is billions of light years away. The finding poses a cosmic puzzle: How could a galaxy 300 million light years away contain a stellar object several billion light years away?
The team’s findings, which were presented today in San Diego at the January meeting of the American Astronomical Society and which will appear in the February 10 issue of the Astrophysical Journal, raise a fundamental problem for astronomers who had long assumed that the “high redshifts” in the light spectra of quasars meant these objects were among the fastest receding objects in the universe and, therefore, billions of light years away.
“Most people have wanted to argue that quasars are right at the edge of the universe,” said Geoffrey Burbidge, a professor of physics and astronomer at the University of California at San Diego’s Center for Astrophysics and Space Sciences and a member of the team. “But too many of them are being found closely associated with nearby, active galaxies for this to be accidental. If this quasar is physically associated with this galaxy, it must be close by.”
Astronomers generally estimate the distances to stellar objects by the speed with which they are receding from the earth. That recession velocity is calculated by measuring the amount the star’s light spectra is shifted to the lower frequency, or red end, of the light spectrum. This physical phenomenon, known as the Doppler Effect, can be experienced by someone standing near train tracks when the whistle or engine sounds from a moving train becomes lower in pitch, or sound frequency, as the train travels past.
Astronomers have used redshifts and the known brightness of stars as fundamental yardsticks to measure the distances to stars and galaxies. However, Burbidge said they have been unable to account for the growing number of quasi-stellar objects, or quasars—intense concentrations of energy believed to be produced by the swirling gas and dust surrounding massive black holes—with high redshifts that have been closely associated with nearby galaxies.
“If it weren’t for this redshift dilemma, astronomers would have thought quasars originated from these galaxies or were fired out from them like bullets or cannon balls,” he added.
The discovery reported by the team of astronomers, which includes his spouse, E. Margaret Burbidge, another noted astronomer and professor of physics at UCSD, is especially significant because it is the most extreme example of a quasar with a very large redshift in a nearby galaxy.
“No one has found a quasar with such a high redshift, with a redshift of 2.11, so close to the center of an active galaxy,” said Geoffrey Burbidge.
Margaret Burbidge, who reported the team’s finding at the meeting, said the quasar was first detected by the ROSAT X-ray satellite operated by the Max-Planck Institute for Astrophysics in Garching, Germany and found to be closely associated with the nucleus of the spiral galaxy NGC 7319. That galaxy is unusual because it lies in a group of interacting galaxies called Stephan’s Quintet.
Using a three-meter telescope operated by the University of California at Lick Observatory in the mountains above San Jose and the university’s 10-meter Keck I telescope on Mauna Kea in Hawaii, she and her team measured the redshifts of the spiral galaxy and quasar and found that the quasar appears to be interacting with the interstellar gas within the galaxy.
Because quasars and black holes are generally found within the most energetic parts of galaxies, their centers, the astronomers are further persuaded that this particular quasar resides within this spiral galaxy. Geoffrey Burbidge added that the fact that the quasar is so close to the center of this galaxy, only 8 arc seconds from the nucleus, and does not appear to be shrouded in any way by interstellar gas make it highly unlikely that the quasar lies far behind the galaxy, its light shining through the galaxy near its center by “an accident of projection.”
“If this quasar is close by, its redshift cannot be due to the expansion of the universe,” he adds. “If this is the case, this discovery casts doubt on the whole idea that quasars are very far away and can be used to do cosmology.”
Other members of the team, besides Geoffrey and Margaret Burbidge, included Vesa Junkkarinen, a research physicist at UCSD; Pasquale Galianni of the University of Lecce in Italy; and Halton Arp and Stefano Zibetti of the Max-Planck Institute for Astrophysics in Garching, Germany.
Unlikely, since the "Big Bang" theory has been confirmed in many ways already, and as far as I know doesn't depend on what quasars may or may not be anyway.
I don't expect this will have dramatic implications for cosmology. Quasars aren't used as part of the "distance ladder", as we have no idea how intrinsically bright they are. For cosmological distances, Type 1a supernovae are used.
The implications for quasar research, by contrast, are huge.
Not likely. Probably it's just the nature of quasars that's the real issue. The BB is supported by other evidence than just the redshifts.
The Four Pillars of the Standard Cosmology.
I think Yo-yo was referring to the Cepheid variables that are used to calibrate the redshift-distance relation. FWIW, I think that's pretty solid. In fact, that's what the Hubble Space Telescope was designed to measure.
I've wondered for some time if the fundamental assumption for cosmology could be flawed - that some of the redshifts in question could be from gravitational forces.
Gravitational Redshift?
Until the J'em Hadar show up, of course.
I'm delighted you've arrived. My ability to deal with this is very limited indeed.
"That would be REALLY cool, to find a worm-hole that was stable!"
Yeah! But how usable would it be 300 million light years away?
:0)
This dissent from normal, accepted Science should be denigrated and censored. What should we call them...quasarists?
>> If I used that same color theory with car headlights on the highway, I'd have run into someone with HID lights by now.<<
Yes, because HID lights are produced by a different gas.
Each element gives off a different spectrum when burned. It's not just a single color, but an entire array of colors, all in relative proportions to each other.
>> I am not an astronomer, but I never did accept the stipulation that all stars of a certain type are of a certain brightness, <<
It's not brightness, but color. And they can measure color in billions of measures your eyes can't.
One damnable effect of idiot liberals in fields like sociology and psychology and politics is that they weaken the concept of "expert." The physicists are men a thousand times more intelligent than you or I. That doesn't mean they are wise (case in point: Steven Hawkins), but it does mean that you're unlikely to an uneducated critique that is going to get them to slap their heads and say, "why didn't we think of that!"
My opinions aren't worth all that much. All I do is try to follow what the smart guys are discovering.
|
There was a time in the recent past when many astonomers were confused by the fact that some stars appeared to be older than the presumed age of the actual universe, but later realized that it was an observational anomaly, as you put it. I think this may turn out to be a similar instance.
In order for a gravity to cause the quasar redshifts, essentially all of the radiating matter would have to park itself impossibly close to the quasar. It's physically possible, but contrived. You not only have to balance a huge amount of matter right on the edge of the event horizon, you also have to prevent other matter from forming a normal accretion disk with a second, more normal redshift, which would dominate the quasar's spectrum.
That's something different. You may be thinking of Cepheid Variable Stars, which as it turns out have a closely linked period of brightness variation to absolute brightness. I don't think there's many who question the perodicity/brightness connection of Cepheid variable stars.
The article is referring to detecting the Doppler shift of spectra in the light from an object in space, and using that to infer if the object is moving away or towards the observer. It's a theory that is easily observable in many areas of nature. There are two leaps of faith coming into play here. First is when the observer assumes that because an object appears to be moving away from the observer (based on its spectra), that it in FACT moving away from the observer, and second is assuming that because an object is moving away from you now, that it has always been moving away from you. Really cool stuff! As for me, I've never been completely convinced that a high red/blue shift is absolute proof of a high relative velocity, but it appears to have fit well with observations up to this point. This'll be interesting to follow up on.
That's the very thing I had in mind. It was the short-lived "age crisis," but it went away.
Yes, but the relationship between redshift and distance is what's at issue here. We know that certain galaxies are redshifted, but how do we know that they are far away? We know it by looking at the Cepheid variables. At some distance, you lose the ability to distinguish individual Cepheids, but fortunately there's enough overlap between the measurably redshifted galaxies and the distinguishable-Cepheid galaxies to get a measure of the Hubble constant. Once you have that, you can plug in redshift and crank out distances--but not, it seems, for quasars!
To say nothing of co-authorship.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
Halton Arp deserves a Nobel Prize if this holds up. Few people in science have taken as much grief as he has in trying to prove something that nobody wanted to hear.