Gamma-ray blazars in the sky

Gamma-ray blazars in the sky
An artist's conception of the Fermi Gamma-Ray Astronomy spacecraft in orbit. Astronomers using infrared observations to help identify Fermi blazar sources amongst the many candidates in a Fermi field-of-view have published two new catalogs of gamma-ray blazars. Credit: NASA/Fermi

When the supermassive black holes at the center of galaxies accrete material, they can eject powerful jets of charged particles at speeds approaching that of light. These particles in turn emit radiation across the electromagnetic spectrum, from radio to gamma-rays. When the jets happen to be aligned toward the Earth, these objects are called blazars, and in a flare they can emit as much radiation as a million billion suns.

NASA's Fermi Gamma Ray Astronomy satellite, launched in 2008, has detected many bright gamma-ray sources, but determining what they are and if any are blazars is difficult because Fermi's resolution on the sky is only about the size of a quarter full moon, and that large area of sky typically contains many sources that could be emitting in the gamma-rays. Moreover, blazars are notoriously variable at and their irregular flickering can make them difficult to pinpoint exactly. Extensive observations of possible candidates with optical or other facilities can be successful but are very time consuming.

A team of astronomers including CfA astronomers Raffaele D'Abrusco and Howard Smith found that the infrared colors of blazars are generally unique because the emission, rather than from hot dust as is typical, is instead coming from processes associated with the jets. They used color data from the Wide-field Infrared Survey Explorer (WISE) in conjunction with catalogs of radio source to identify the most promising gamma-ray candidate objects in the Fermi survey and for the past several years have followed them up, with a success rate confirming blazars of about 90 percent.

The same team of astronomers has now extended their original 2014 work using all the most recent data collected by Fermi and a for analyzing the WISE data, and have produced two new catalogs of WISE blazar candidates with a total of 15,120 candidate sources. The new work will enable many more detailed followup analyses of gamma-ray blazars, as well as other kinds of blazars. The gamma-ray sky is known to reflect, in its dramatic appearance, many other kinds of extreme physical processes, for example possible dark matter annihilation activity in some scenarios, and the new catalogs will enable a much more complete investigation of the dominant contributor to the universe: blazars.


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Radio weak blazars

More information: Raffaele D'Abrusco et al. Two new catalogs of blazar candidates in the WISE infrared sky. arXiv:1903.11124 [astro-ph.HE]. arxiv.org/abs/1903.11124
Citation: Gamma-ray blazars in the sky (2019, April 5) retrieved 22 May 2019 from https://phys.org/news/2019-04-gamma-ray-blazars-sky.html
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Apr 05, 2019
"When the jets happen to be aligned toward the Earth, these objects are called blazars, and in a flare they can emit as much radiation as a million billion suns."
Hyperbole alert. I can't prove it, but I suspect they are basing this power-estimate on an inverse-square-law of intensity, as with Type 1a supernovae, which emit light in all directions. The jets are highly beamed, however, like a laser, and their intensity may decrease only very slowly with distance. They may "only" emit as much radiation as a billion suns.

Apr 05, 2019
Blazers and Quasars

Any typical radio galaxy
becomes a blazer
when
its spin jet axis
is pointing directly at earth
but
exactly the same problem remains
as
Actual proof still remains in artists simulations
https://news.wisc...ault.jpg

Apr 05, 2019
^^^^Go away Granville. Your posts are pointless and add nothing to the discussion. Due to you having not a scooby about the subject matter.

Apr 05, 2019
@Castrogiovanni.

From the above article:
... jets of charged particles at speeds approaching that of light. These particles in turn emit radiation across the electromagnetic spectrum, from radio to gamma-rays.
Again, mainstream is acknowledging the fact that RADIO wavelengths (including MICROWAVElengths) are ubiquitously produced by these/other processes ONGOING all over the universe all the time.

Hence why I have long been pointing out that the CMB (cosmic MICROWAVE background) is NOT dependent on alleged Big Bang 'provenance' at all.

So, @Castro, will you be the first to acknowledge that what I have been pointing out re CMB (ie, it NOT being 'supporting evidence' for alleged Big Bang) was correct all along?

Or will you pretend to ignore in the hope that your wilful bias/denial will make the 'inconvenient' reality 'go away'? Your response now will define the caliber of your character and objectivity 'credentials' in future science discourse here. Good luck. :)

Apr 05, 2019
You have to admit, jonesy
^^^^Go away Granville. Your posts are pointless and add nothing to the discussion. Due to you having not a scooby about the subject matter.

Theirs consistency
In these Artists simulations
https://news.wisc...ault.jpg

Apr 05, 2019
In search of black holes and dark matter astrophysicists are relying on indirect observations. It would seem that the measurement of the event horizon of a black hole directly would be a direct evidence. However, by the nature of a horizon, any real measurement of the event horizon will be indirect. The Event Horizon Telescope will get picture of the silhouette of the Sgr A* which is due to optical effects of spacetime outside of the event horizon. The result will be determined by the simple quality of the resulting image that does not depend on the properties of the spacetime within the image. So, it will be also indirect and an existence of BH is a hypothesis.
https://www.acade...ilky_Way

Apr 05, 2019
Well RC that would be a neato idea you are espousing.
Now if only you could educate us all
showing us your math
confirming your theory
clarifying how a present day MW event is beating the Speed of Light
to travel back in Time 13+billion years?

While simultaneously dissipating to the present day measurements of the MW energy level of the original BB blast of MW background radiation.
Presently being observed across tens of billions of Light Years?

Unless of course you want to claim that what we think we are observing is just an illusionist trick?
By the Trickster Coyote Goddess?
Cause I can get down with that as a perfectly sensible explanation.
Perfect for our monkey brains!

Apr 06, 2019
@rrwillsj.
RC that would be a neato idea you are espousing.
Merely 'connecting the dots' of acknowledged 'mainstream data', to arrive at the tenable logical/scientific conclusion. No biggie....IF one is objective, logical and attentive to the facts as opposed being distracted by BB biased assumptions/interpretations re same data. :)
clarifying how a present day MW event is beating the Speed of Light to travel back in Time 13+billion years?
Who said it needed to, mate?...not me! You just made up that strawman nonsense without thinking it through before putting in a silly question that has no logic to it at all. :)
While simultaneously dissipating to the present day measurements of the MW energy level of the original BB blast of MW background radiation.
For one thing, it is YOUR Big Bang biased ASSUMPTION that the CMB we see now is from BB. In fact, CMB is from the ONGOING processes I/MAINSTREAM just pointed out SMEAR the WHOLE MW spectrum into RADIO LENGTHS. :)

Apr 06, 2019
they can eject powerful jets of charged particles at speeds approaching that of light. These particles in turn emit radiation across the electromagnetic spectrum, from radio to gamma-rays.

That is what electric currents do, it is no wonder this radiation is visible in every direction we look.

Apr 06, 2019
they can eject powerful jets of charged particles at speeds approaching that of light. These particles in turn emit radiation across the electromagnetic spectrum, from radio to gamma-rays.

That is what electric currents do, it is no wonder this radiation is visible in every direction we look.


More pseudoscientific crap.

Apr 06, 2019
We have already established these jets are electric currents, yet your willful ignorance continues to blind you.

Apr 06, 2019
ahh cant, you dogmatically confuse the words "claim" & "proof"
Whatever nonsense you "claim" to receive from you ouiija board technology?
Is not "[roof" until real scientific research proves it to be true. Including confirmation by peer review.

For instance, if I should "claim" that you are Homo Sapiens?
& you continue to "prove" me wrong?

Obviously. I am the one who needs to reconsider my opinion of you.
To match the opinions of your peers.

Apr 06, 2019
We have already established these jets are electric currents, yet your willful ignorance continues to blind you.


No we haven't. Some of them may be confined by magnetic fields, and a current will be present. Some may not.
And none of this has anything to do with falsified EU/PC woo. These are jets from BHs. And those loons don't believe in such things. Others are from supernovae, and the EU idiots don't believe in them. Others come from nascent stars forming in accretion disks, and EU idiots don't believe stars form like that.

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