Radio galaxy discovery near Earth spurs more questions

May 23, 2014 by Denise Cahill
A radio galaxy is a galaxy which is associated with jets of emission which show up in radio wavelengths. Astronomers have worked out that these jets come from super massive black holes at the centres of these galaxies. The region around the black hole is also visible in the radio, and this shows up as a bright 'core' in between the wider plumes. Credit: Dr Natasha Hurley-Walker

Western Australia astronomers have discovered a radio galaxy near Earth by accident. The previously unknown radio galaxy is considered quite close to Earth, and was discovered late last year.

ICRAR astronomer Dr Natasha Hurley-Walker spotted the galaxy while in a team meeting last year looking at a captured by the Murchison Widefield Array (MWA).

"I just saw this thing out of the corner of my eye and thought, that doesn't look right and it turns out it is one of these and it is very, very faint and it is very nearby," she says.

But while consider the galaxy quite close, it is redshift 0.0178 from and would take 248 million light years to get there.

Dr Hurley-Walker says the radio galaxy, named NGC1434 after the galaxy it is in, is very large, which may explain why astronomers had not spotted it in the past.

It is not dissimilar to earth in that it has star formation going on, and it has what is called a dust blain, which suggests it has not been agitated by galaxies colliding (mergers).

"The interesting thing about the object I found is that it's being hosted by a , like our own," she says.

"This is a very rare occurrence—this is only the fifth of this type to be discovered, and by far the faintest."

Because it is quite near earth, it means the galaxy is quite old, possibly forming within a billion years after the big bang.

Dr Hurley-Walker says the discovery is also intriguing because at some point in its history the central black hole switched off but the have persisted.

Jets are narrow beams of matter spat out at high speed from near a black hole.

"That is kind of unusual because normally when we see these things, they are usually still on, have been for quite some time and that tells us the jets have persisted for a very long time.

"[This] is kind of interesting because it tells us that the electrons out there must have been very hot originally so there could still be radiation now," she says.

She does not know why the black hole switched off.

But to unlock the reasons and to find out more, she says researchers will need to observe the galaxy's central core with a high-resolution instrument with a very narrow field of view.

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User comments : 14

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Realist99
4.9 / 5 (7) May 23, 2014
Who writes this stuff? How can a galaxy be "not dissimilar to Earth"? Comparing a planet and a galaxy is the ultimate "apples-to-oranges" comparison.
Anda
5 / 5 (4) May 23, 2014
Ok Realist, you were faster. "Galaxy close to earth", "Galaxy not dissimilar to earth"...
In the last months the level of articles has dropped dramatically...
TechnoCreed
4.3 / 5 (6) May 23, 2014
Who writes this stuff? How can a galaxy be "not dissimilar to Earth"? Comparing a planet and a galaxy is the ultimate "apples-to-oranges" comparison.


Ok Realist, you were faster. "Galaxy close to earth", "Galaxy not dissimilar to earth"...
In the last months the level of articles has dropped dramatically...


I agree! It felt as if I was reading something written by a 10 year old... Or Translated by Google.
del2
5 / 5 (4) May 23, 2014
"would take 248 million light years to get there" should presumably read "would take light 248 million years to get there"
MorganW
5 / 5 (6) May 23, 2014
I feel dumber having read that, than I did before. How do they make the leap that because the galaxy is very near earth, that means that it's quite old?
Fisty_McBeefpunch
4.8 / 5 (4) May 23, 2014
I had a hard time translating this and English is my primary language.
katesisco
1 / 5 (7) May 23, 2014
http://phys.org/n...tml#nRlv
These clustered black holes are perhaps more magnetically bound? Or like globular clusters they are held by 'binding energy? Still trying to understand binding energy in relation to magnetism.
Here there may be a lack of magnetism at the black hole site? Maybe what our Fermi bubbles are?
yyz
5 / 5 (9) May 23, 2014
Am having a hard time, as the other posters here, of deciphering this "news". The gist of this concerns the discovery of relic radio jets in a (previously known) lenticular/disk galaxy (NGC 1434 is a S0-type galaxy), which is a rather rare phenomena for this type of galaxy.

However, this point seems lost among some of the confusing and inaccurate statements in this article (which is copypasta from the original PR, BTW).

What is a "dust blain"(dust lane)?.

I'm curious why the given redshift for NGC 1434(z=0.0178) is at odds with the NED and SIMBAD databases(z=0.0336). The NED/SIMBAD value puts this galaxy at a distance of ~450 Mly; not in the Local Group but farther than the Virgo, Coma or Perseus galaxy clusters.

I guess we'll have to wait to see the paper, but according to the press release the it's still being written(!) and is to be published "later this year".
cantdrive85
1.7 / 5 (6) May 23, 2014
I feel dumber having read that, than I did before.

Welcome to the club, it is a regular occurrence when it comes to articles about astrophysics.
Urgelt
5 / 5 (4) May 23, 2014
Totally incoherent. It's close, so it must be old? Unusually large means how large, exactly? Yikes, if a student submitted a paper in this shape, he'd never escape with a passing grade.
Mimath224
4.3 / 5 (3) May 23, 2014
When I read the title I thought while we have been spending a lot of time bombarding meteor defense a giant 'space amoeba' had crept up on us. Phew!
Mr Som-o
4.8 / 5 (4) May 23, 2014
Being a newbie here, and not wanting to my proclaim my ignorance, I'm sure glad more senior and knowledgeable readers voiced what I was thinking about this article.
rogerbcooper
5 / 5 (1) May 25, 2014
There are some fundamental inaccuracies in this article. The object is not near NCG 1434 (3h46m12.8s, -9°40'57"), but NGC 1534 (4h8'46.3", -62°47'52"), a near-by spiral galaxy in Reticulum similar to the Milky Way. See sky-map.org.

The essence of Dr. Hurley-Walker's discovery is a strong low frequency radio source that appears to be a remnant of a jet ejected from NGC 1534. That would suggest that this galaxy was in the past a "radio galaxy" actively ejecting matter from a black hole near its core.
Nik_2213
5 / 5 (2) May 25, 2014
"...have discovered a radio galaxy near Earth"

Ouch. Just who takes an interesting, rational report and generates this fluffy nonsense from it ??

Almost as bad as the 'Atomic Compass' trumpeted in one of our 'heavyweight' papers. Some-how, the reporter had taken news of modest progress towards a three-axis atomic accelerometer and, uh, lost the plot...