Black Hole Jets Pack One, Two Punch in Radio, Gamma Rays
Written by Anne Minard
Compact, ultrabright jets at supermassive black holes in active galaxies were already known to pack an impressive punch in radio waves. And now, an international team of scientists says they're kicking out high-energy gamma rays too.
Distant galaxies host the super massive black holes, which are billions of times heavier than our Sun but are confined to a region no larger than our solar system. The rapidly rotating black holes attract stars, gas and dust, creating huge magnetic fields. The magnetic forces can trap some of the infalling gas and focus it into narrow jets that flow away from the core of the galaxy at velocities approaching the speed of light.
Theoreticians and observers alike have been puzzling for decades about the nature and composition of these energetic radio-emitting jets, and if they also radiate in other parts of the electromagnetic spectrum.
Some hints were provided by the EGRET instrument on the Compton Gamma Ray Observatory telescope in the late 1990s and more recent discoveries of X-ray emission made by the Chandra Observatory.
Now, astronomers from Germany, the United States and Spain have paired observations of the bright gamma-ray sky by NASA’s orbiting Fermi Gamma-ray Space Telescope with those from the ground-based Very Long Baseline Array radio telescope in the United States to observe the material expelled with enormous speeds away from the black holes in the heart of very remote galaxies. These ejections take the form of narrow jets in radio telescope images, and appear to be producing the gamma-rays detected by Fermi.
“These objects are amazing: finally we know for sure that the fastest, most compact, and brightest jets that we see with radio telescopes are the ones which are able to kick the light up to the highest energies," said Yuri Kovalev, Humboldt Fellow and scientist at the Max Planck Institute for Radio Astronomy.
The gamma-ray bright sources are now shown to be brighter, more compact and faster at light year scales than the gamma-ray quiet sources.
Fermi, formerly known as GLAST, has been operational since the summer of 2008. The telescope records an image of the whole sky every few hours to explore the most extreme environments in the universe, including pulsars and gamma-ray bursts, as well as black holes in galactic nuclei. Gamma-ray observations alone are not enough to discern the exact location of the radiation, however. The VLBA serves as a magnifying glass for zeroing in on the most energetic processes in the distant universe. Many objects found by Fermi to be extreme in gamma-rays are emitting strong bursts of radio emission at the same time.
The Very Long Baseline Array is a continent-wide system of ten radio telescope antennas, ranging from Hawaii in the west to the U.S. Virgin Islands in the east. Dedicated in 1993, the VLBA is operated by the U.S. National Radio Astronomy Observatory and is designed to monitor the brightest objects in the Universe at the highest available resolution in astronomy.
The work for astronomers does not stop here: the team has concluded that the region of the jet closest to the black hole is undoubtedly the place where the gamma-ray and the radio bursts of light originate in about the same time. However, some parts of the puzzle have yet to be resolved, they say: some bright gamma-ray sources in the sky appear to have no radio or optical counterpart — their nature is still completely unknown.
Source: Max-Planck Institute. The findings are being reported in two publications in the May 1, 2009 issue of Astrophysical Journal Letters (here and here).
Links:
Very Long Baseline Array
VLBA Monitoring of AGN Jets: The MOJAVE Project
Fermi Gamma-ray Space Telescope LAT Group
Filed under: Astronomy, Black Holes, Gamma Ray Bursts
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April 22nd, 2009 at 1:27 pm
Per a paper published in Nature:
"Scientists…managed to observe a super-sized supernova explosion from start to finish, including the black hole ending, the star has now become a black hole."
– Avishay Gal-Yam, Head of the Experimental Astrophysic Group Weizmann Institute of Science, Israel — one of the top ranking reseach institutions s in the world. And Gal-Yam is a frequent peer-reviewer.
In response to the above statement Stephen Crothers, a mathemetician, challenged Mr. Gal-Yam, thus:
"As an observational astronomer you of course know that nobody has ever found a black hole. To invalidate the concept of a black hole it is sufficient to show that the infinitely dense point-mass singularity of the alledged black hole violates the Theory of Relativity. Infinite densities are forebidden by Special Relativity. Since General Relativity can not violate Special Relativity too, ipso facto, forbids infinite densities.
Mr. Gal-Yam answered Crothers challenge, thus:
"We agree that our work does not provide direct evidence for the formation of a black hole."
While disparaging and somewhat humorous this video records challenges and responses regarding so-called "black holes".
See, this YouTube.
April 22nd, 2009 at 2:33 pm
@ Anaconda, thanks for the link to the video. I got a few chuckles out of it. I'm familiar with Steven Crothers and have already checked out his website. Unquestionably a smart guy, I've seen his posts at PhysOrg.com & some quite detailed refutations ( he was also forced out of his doctorate studies at an Australian college for his wrongheaded assumptions. Boy does he have an axe to grind.) Anyway, thanks for the video, I'm gonna see if they'll post it over at Cosmic Variance. They'll get a kick out of it!
April 22nd, 2009 at 4:01 pm
@ Jon Hanford:
Are his positions wrongheaded or just inconvient for those determined to foist the idea of so-called "black holes" onto the general public.
Taking your word for it, why was he forced out of his doctorate studies at an Australian college? Because he actually studied and understood the original documents, papers, and went to his professors and openly challenged the "black hole" hypothesis?
Besides, your response fails to refute the merits of Crothers' claims. And, the responses from the various individuals challenged by Crothers speaks for themselves.
They essentially all made retractions of their prior statements when confronted by Crother's understanding of Special and General Relativity.
Perhaps that is why Einstein, himself, never subscribed to the "black hole" hypothesis.
But there is something much more basic about the problem with the so-called "black hole" hypothesis: Mathematics can't predict whether the ultra-high density of a "black hole" is possible.
Let me state that again:
Mathematics can't predict whether the ultra-high density of a "black hole" is possible.
Mathematics is formalized language that quantifies observation & measurement by way of postscript analysis of those observations & measurements.
So-called "neutron" stars are claimed to be 100 million tons per cubic centimeter, about the size of your average pinkey finger.
There is NO observation & measurement that suggests this kind of density is possible, let alone the "infinite" density of a "black hole". How much more dense does a "black hole" need to be than a "neutron" star?
There is no answer because "infinity" can't be quantified.
It's a fudge factor that goes along with the "black box".
The paper from the Max-Planck Institute outlined in the, above, post is a prime example of the fanciful imaginings that are being foisted as scientific fact.
All the observed & measured phenomenon cited by the paper are better explained by electromagnetic processes.
April 22nd, 2009 at 4:56 pm
@anaconda
Bravo.
Look at all the press releases for papers that have come out in the past few weeks that question the Einsteinian relativity/gravity-centric universe. Most of them are directly related to EM/plasma properties/phenomena.
To paraphrase something I read the other day:
It's like relaxing on the bank of a river, after drinking your fill, and watching somebody standing neck deep in the middle, dying of thirst.
Waddayadoo?
Sort of like leading a horse to water…they'll figure it out once they get thirsty enough.
April 22nd, 2009 at 5:09 pm
How much they pay you guys to post on this site? You guys spend more time blathering on about EU here than I spend my time at work.
April 22nd, 2009 at 5:21 pm
I read Crother's paper in detail a couple of weeks ago. His analysis suffers from some problems. His use of the Theorema, which argues that the "R" can't be considered a radius, would work in two dimensions. Since this is in four dimensions there are extrinsic curvatures in addition to this 2-d surface which make his argument inappropriate.
I read the Schwarzschild paper. His metric term
g_{tt} = 1 – A/(r^3 + A^3)^{1/3}
assumes a bulk material objects, and this is how K. S. saw this as modelled. The frequently used version removes this assumption.
The remainder of Crother's paper is frankly a sort of polemic that repeats itself. In fact it really amounts to saying that general relativity is wrong. I frankly found the second half of the paper rather painful to read, as it was a bit like reading the second half of an Ayn Rand novel — a rant that won't end
.
That is about all that Crother's paper really deserves, and frankly it was a waste of a Saturday reading it, when I could have been doing other work or trout fishing.
Lawrence B. Crowell
April 22nd, 2009 at 5:28 pm
Oh and Yeah. Crother's argument that
Ricc = 0
means there is not matter in the black hole is specious. Ricc = 0 is equivalent to looking at a gaussian surface that does not enclose the charge. This does not mean the charge does not exist. Ricc = 0 simply indicate the region of integration, or how the solution is derived. it does not mean that the black hole has no mass.
Lawrence B. Crowell
April 22nd, 2009 at 5:37 pm
OK, back on topic. =) My favorite image of a black hole jet is that which is located in M87. You do NOT want be in the path of THAT thing.
"Hey why did everything emit a blue flash… ERK!"
April 22nd, 2009 at 6:23 pm
@ Lawrence B. Crowell:
I'll be the first one to admit I'm not skilled at mathematics. So, I'll have to leave that up to duelling mathematicians.
Challenge and response, and rebuttal and surrebuttal are all part of scientific dialogue.
Although, as Nikola Tesla, the great electrical inventor, stated: "To say that in the presence of large bodies space becomes curved is equivalent to stating something can act upon nothing, I, for one, refuse to subscribe to such a view."
Crowell states: "Since this is in four dimensions…"
No. Time is not a physical dimension.
@ sorey:
I'm interested in your report that press releases are rolling off the internet challenging General Relativity and the space-time curvature.
I'm even more intriqued, solrey, by your statement:
"Most of them are directly related to EM/plasma properties/phenomena."
To me, it seems about time. Gravity as a function of geometry based on 'thought experiments' does not carry alot of weight as opposed to gravity intrinsic to matter.
Also, it brings up the fact that General Relativity and Quantum Mechanics are non-compatible — one or the other is in error.
But Crowell, you skipped right by the statement:
Mathematics can’t predict whether the ultra-high density of a “black hole” is possible.
Again, silence speaks louder than words.
April 22nd, 2009 at 6:28 pm
In no way do I say that gravity is the only force at work in astrophysics. Yet I am certain that it is not all electromagnetism. Gravity is real, we land robots in craters marked as "targets" using it.
As for wacko, I suppose other terms might suffice as well: crackpot, crank and so forth. There is no scientific revolution awaiting EU and PU in the future. All this amounts to is lots of confusion and smokescreen that can reduce the signal to noise ratio out there. As such you and thousands of other cranks are really doing a disservice.
Lawrence B. Crowell
April 22nd, 2009 at 7:50 pm
Mathematics can’t predict whether the ultra-high density of a “black hole” is possible.
I'm not sure what you mean by predict? It already has, do you mean math alone cannot prove the existence of a black hole?
Overall, a lot of these EU questions about black holes strike me as disingenuous. Most people here already know that nobody has been able to reconcile GR with the zero dimensional particles of the standard model. I'm not really sure how somebody would define the density of a single 0 dimensional particle anyway.
No. Time is not a physical dimension.
As I read it, Cromwell's problem was that Crother's work was primarily in 2-d. I know you guys don't subscribe to the curved space-time of GR but that still leaves one spatial dimension unaccounted for.
April 22nd, 2009 at 8:29 pm
The incompatibility of general relativity and quantum mechanics is not an error. It is a question, similar to the early 20th century incompatibility between classical mechanics and electrodynamics with regards to the atom or the blackbody radiation problem.
Lawrence B. Crowell
April 22nd, 2009 at 8:35 pm
Crother's argument was that the R^2 in the line element in two dimensions is the curvature C ~1/R^2, which in pure 2-d has no radial meaning. Yet this is embedded in a larger space, and the Theorema Egregium of Gauss applies to 2-d. So the argument is inapplicable.
As for time being a physical dimension, we might ponder whether any spatial dimension is "physical."
The singularity in a black hole is a classical interpretation, which quantum mechanically is likely changed. We need not get hung up on the interior singularity to interpret astrophysical data as corresponding to what a black hole would effect, where nothing else appears to match that effect.
Lawrence B. Crowell
April 22nd, 2009 at 10:06 pm
@ Lawrence B. Crowell:
Those that get swallowed by a revolution rarely see it coming until it has already happened.
In situ observation & measurement of near-space keep detecting electromagnetism in significant roles.
Are all those scientists reporting electromagnetic phenomenon in near-space "crackpots"?
Crowell, you might be painting yourself into a corner.
I suspect that when Man sends a probe out to and beyond the heliopause, it will be found to be similar to the Earth's magnetopause — an electromagnetic double layer.
I suspect that Science will also find that the heliopause is like a window with dirt on it. It will be that much clearer how much electromagnetism is an significant participant in the Universe once Man gets his probes beyond the heliopause.
And rest assured, Man will get probes beyond the heliopause.
Science (empiricism) based astronomy will wrest control from the pure mathematicians who now control "modern" astronomy.
April 23rd, 2009 at 9:59 am
Lawrence B. Crowell Says:
"As for wacko, I suppose other terms might suffice as well: crackpot, crank and so forth. There is no scientific revolution awaiting EU and PU in the future"
Of course there is! When the planet X in 2012 comes around with their charged plasma drive so they can ride the cosmic plasma waves of electric hydroplasma, they will prove to the infidels that we are all wrong and that EU was right! LOL
Of course THE Scientists are all in complot!
April 23rd, 2009 at 10:07 am
Anaconda Says:
"Mathematics can’t predict whether the ultra-high density of a “black hole” is possible."
If I read these type of sencences that I immediately think about creationsts that clame something similar like "No transitional fossiles have even been found" while they are staring at a transitional fossile!
Anaconda, how would you know that mathematics can't do that? How would you know that mathematics can't do that in the future? Maybe some day Mathematicians will find a new mathematical way of formulation it percisely with high accuracy!
Look at all the mathematical techniques developed during the quantum times that did not exist before that time?
April 23rd, 2009 at 10:13 am
Anaconda Says:
"Science (empiricism) based astronomy will wrest control from the pure mathematicians who now control “modern” astronomy."
Anaconda, what empiricism based science does prove that that big yellow ball on a sunny day is a big gasous ball of plasma called the sun? Have you emerical evidence that it is inded plasma and no some proected image from an alien spieces that is trying to foo us into believeing that this is a sun?
Have you real physical evidence that it is really the sun and it is really plasma? Do you have plasma from that sun in some jar at your shelf that proves that this is plasma?
Do you also have real vacuum plasma in one of your jars? Since you clame that space is filled with plasma can you empherically prover this to be true?
The only empherical evidence you have is yous plasma in your laboratory experiments,n but you have no real empherical evidence that that there is plasma out there!
April 23rd, 2009 at 10:53 am
@ olaf:
It's rather simple really, mathematics is a postcript analysis & interpretation of observation & measurement.
NO, I repeat no observation & measurement has even begun to observe & measure ultra-high densities.
It is improper to claim mathematics can predict ultra-high density. Of course, that hasn't stopped pure mathematicians from doing just that.
Olaf states: "If I read these type of sencences that I immediately think about creationsts that claim something similar like “No transitional fossiles have even been found” while they are staring at a transitional fossile!"
Ironic that you, olaf, a confirmed "big banger" should mention disparagingly "creationists", since "big bangers" subscribe to:
"Something out of nothing."
Olar, I don't care how you put it, the "big bang" is creationist, the only difference is when the "creation" happened, either 6,000 years ago, or 13.7 billion years ago.
Olaf, didn't I read that you subscribe to the idea that the Universe started off smaller than an atom?
Olaf, did you know the person who first came up with the idea for the "big bang" was a Roman Catholic priest?
I want observation & measurement — in other words…show me.
You, Olaf, on the other hand subscribe to a miracle: Smaller than an atom expanding to the known Universe.
Yeah, right.
Olaf, you are the CREATIONIST by your own words.
I am an empiricist. Show me, don't tell me some mathamatical equation says it's possible.
Observation & measurement talks.
Theoretical equations walk…
April 23rd, 2009 at 11:13 am
@ Olaf:
Olaf states: "Anaconda, how would you know that mathematics can’t do that? How would you know that mathematics can’t do that in the future? Maybe some day Mathematicians will find a new mathematical way of formulation it percisely with high accuracy!"
How do I know that?
Because mathematics is a description of what has been observed & measured. It quantifies physical relationships that have been already observed & measured.
Since nothing even approaching the ultra-high densities required of "neutron" stars (100 million tons per cubic centimeter) has ever been observed, let alone the "infinite" density required for a "black hole", whatever that is, since "infinity" can't be quantfied, mathematics has no insight on if ultra-high density exists in nature.
Let me repeat:
Mathematics has no insight or ability to state that ultra-high density is possible in nature.
Mathematics is exclusively a postscript langauge of description of known physical relationships.
Ultra-high density is unknown to Man.
Olaf states: "Have you emerical evidence that it is inded plasma and no some proected image from an alien spieces that is trying to foo us into believeing that this is a sun? "
Yes, Olaf, there is empirical evidence the Sun is, indeed, plasma.
Sometimes, Olaf, you come across as an idol worshipping, superstitious person.
Frankly, Olaf, my take on you is that you want to be squarely in the middle of the herd, even if that herd is running off a cliff.
April 23rd, 2009 at 4:39 pm
Anaconda Says:
I suspect that when Man sends a probe out to and beyond the heliopause, it will be found to be similar to the Earth’s magnetopause — an electromagnetic double layer.
—————————-
If I were of a mind, I might take that as a personal insult. I worked in the early 90's on celestial dynamics and spacecraft navigation. I can testify with no qualifications that neither I nor anyone else made such a category error. To presume so, and that your plasma double layer nonsense managed to reproduce exactly the same results that gravity does. is laughably absurd.
Look gravity works great on Earth. Thing here are generally electrically neutral, and my body has no current running through it. Yet curiously the chair that keeps my butt from falling further. This normal force of the chair and ultimately the ground counters geodesic motion which would cause me to proceed to the Earth's center.
These are elementary considerations. I can only advise looking at Hawking & Ellis "Large scale Structure of Spacetime" with respect to black holes.
Lawrence B. Crowell