Can A 'Distant' Quasar Lie Within A Nearby Galaxy?

University of California, San Diego ^ | 10 January 2005 | Kim McDonald

[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.

[PatrickHenry]

All the underlining and bold font is added by me, your humble poster.

Either this is an observational anomaly that will eventually be cleared up, or ... it's a very big issue indeed.

[PatrickHenry]

Science Ping!

This is an elite subset of the Evolution ping list.

See the list's description in my freeper homepage. Then FReepmail me to be added or dropped.

[Yo-Yo]

I am not an astronomer, but I never did accept the stipulation that all stars of a certain type are of a certain brightness, so the 'red shift' could be used to determine if it is moving towards or away from us.

If I used that same color theory with car headlights on the highway, I'd have run into someone with HID lights by now.

[Alamo-Girl]

Fascinating. Thanks for the ping!

[Slings and Arrows]

WOW ping!

[taxcontrol]

Hmmm, I see this as having the potential to redefine cosmology. If the red-shift must be redefined, the universe could be a much different place than once thought.

[PoorMuttly]

Can A 'Distant' Quasar Lie Within A Nearby Galaxy?

Oh yes, they lie all the time.

Just can't trust 'em.

(hey, y'know this science stuff ain't so hard..)

[Conservative Canuck]

Maybe they're viewing it through a worm-hole? That would be REALLY cool, to find a worm-hole that was stable!

[numberonepal]

How could a galaxy 300 million light years away contain a stellar object several billion light years away?

That stellar object could be traveling faster than c maybe?

... does not appear to be shrouded in any way by interstellar gas make it highly unlikely that the quasar lies far behind the galaxy

My first thought was it could just be behind it. But this suggests not. However, it's light could also be "lensed" by the interstallar matter.

[PatrickHenry]

... I never did accept the stipulation that all stars of a certain type are of a certain brightness, so the 'red shift' could be used to determine if it is moving towards or away from us.

That's not quite the way it works. The original method was to assume that all variable stars (of a very specific type), such as the one in the constellation Cepheus, are the same, because of their similar pattern of growing bright and then dim. We knew (from the parallax method) the distance of the Cepheid variable, so the distance of the others was a simple matter of measuring their brightness. Twice as far meant 1/4 the brightness, 3 times as far meant 1/9 the brightness, etc. The inverse square law.

By spotting Cepheid variables in distant star clusters, an estimate of the distance of the entire cluster could be made. Then, Edwin Hubble noticed that the redshifts of these stars and clusters showed a specific pattern -- the farther away they were, the greater the redshift. In due course, redshift alone came to be used as the measuring rod, and it's been working. Until this quasar business ...

[FormerACLUmember]

Science asking a major WTF!!!!

[Red Badger]

If the universe is expanding, presumably in a globular or spherical manner, out from the point of it's conception, then, like Columbus seeking a quicker route to India, if something is receding from you at a high rate of speed, would it not also be coming at you from behind?

[Edgerunner]

Might the red shift be caused by the extremely steep gravity well the light must climb out of? Quasars have recently been thought of as massive black holes, if I'm not mistaken. Black holes have been found at the center of all galaxies surveyed to date. Light's frequency can be red-shifted by gravity...Just a thought. This is very exciting stuff if what they say is true!(if you go for the cosmological aspects of things...)

[OSHA]

Looks like the universe just got a lot smaller just as I coming to grips with the hugeness of it. Excuse me, I feel a bout of claustrophobia coming on.

[BenLurkin]

“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,”

OR ROCKETS?

[Tamberlane]

If I am not mistaken, discoveries like this one are calling the entire Big Bang hypothesis in question.

[eno_]

Could be the "speed of light is not the same all over, and all the time" issue. It would be interesting if these observations confirmed that.

[PatrickHenry]

Might the red shift be caused by the extremely steep gravity well the light must climb out of?

Gravity can cause a redshift, but I'm informed that the effect of gravity is very slight compared to that of the presumed Doppler Effect. Personally, I don't know this, but my source is very reliable. Pinging a couple of experts in case I've got it wrong.

[Ichneumon]

I am not an astronomer, but I never did accept the stipulation that all stars of a certain type are of a certain brightness, so the 'red shift' could be used to determine if it is moving towards or away from us.

Redshift is not measured by presuming anything about star type or absolute brightness. Instead, they use a spectrograph (basically, a high-tech prism) to separate the light from the star into different light frequencies. Every element, when heated to incandescence (regardless of temperature, as long as it's hot enough to "glow") produces a characteristic pattern of specific narrow-band light frequencies. Hydrogen, for example, emits a pattern like this:

By doing a spectrograph of a star's light, then locating the patterns within it which match hydrogen, helium, and other common elements in stars, scientists can measure where those patterns appear, frequency-wise, relative to where they "ought" to appear -- the difference is the amount of redshift (if the bands show up at lower frequencies than standard), or blueshift (if the bands show up at higher frequencies).

Usually, a redshift indicates that the light source is moving away from us (by a speed determinable by the amount of redshift), but light "climbing" out of an extremely strong gravity field (like from near a black hole or neutron star) can also be redshifted by the effects of gravity.

This latest observation seems to hint that there may be other ways that light can be redshifted too, perhaps concerning something about the physics of quasars. Or maybe quasars are just another type of ultra-gravity phenomenon, in the manner of a black hole.

[Edgerunner]

keep me informed of their opinions. Please...