Star formation near supermassive black holes

June 22, 2015, Harvard-Smithsonian Center for Astrophysics
The bright radio galaxy 3C219. The blue object at the center is its active nucleus powered by a supermassive black hole; red shows the extent of the radio emission. Infrared observations of a complete set of similar galaxies dating from about seven billion years ago find that although star formation is active in these objects, the nuclear activity dominates the luminosity. Credit: NRAO and Parijskij et al.

Most if not all galaxies are thought to host a supermassive black hole in their nuclei, a finding that is both one the most important and amazing in modern astronomy. A supermassive black hole grows by accreting mass, and while growing its feeding frenzy is not hidden from our view—it generates large amounts of energy. During the evolutionary phase in which it is most active, the object is known as an active galactic nucleus (AGN). Although there is a difference of a factor of about one billion in physical size scales between the black hole's accreting environment and its host galaxy, the two sizes are found to be closely correlated, suggesting that there is some kind of feedback between the growth of the black hole and that of its host galaxy. Understanding what the feedback mechanisms are, and how they affect the growth of the galaxy (in particular its star formation), are of paramount importance for our understanding galaxy formation and evolution. Both processes are thought to peak in activity when the universe was only a few billion years old. Neither is particularly well understood.

CfA astronomers Belinda Wilkes, Joanna Kuraszkiewicz, Steve Willner, Matt Ashby, and Giovanni Fazio, along with their colleagues, used the Herschel Space Telescope to study the infrared emission from sixty-four bright, radio and X-ray emitting galaxies with AGN nuclei, and which contain more than one hundred billion solar-masses of stars. Their set is a complete sample of objects of a well-defined class dating from about seven billion years ago, and includes some of the most powerful quasars known. All the objects have large bipolar jets that were driven into intergalactic space by the AGN. The scientists set out to determine how much of the luminosity in these powerful galaxies was due to the AGN and how much was due to activity. The infrared is emitted by dust heated by these two processes, and details of the emission (its typical temperature for example) can help sort out the relative contributions of the two processes.

The astronomers conclude that the star formation rates in these monsters run into the hundreds of solar-masses per year, and therefore reject suggestions that the AGN outflows will quench the star formation in such galaxies. Whatever the details of the growth feedback mechanism, therefore, they do not suppress the star formation. Nevertheless, despite the active star formation underway, the majority of the luminosity is due to the AGN, even during periods when the star formation is most active. Their paper is also significant because it can explain the principal observational differences between the galaxies in this set simply by the orientation of their disk to our line-of-sight, with the large, double-lobed jet sources being seen edge on and the quasars being seen more face-on.

Explore further: Accreting supermassive black holes in the early universe

More information: "Star Formation in z > 1 3CR Host Galaxies as Seen by Herschel," A&A, 575, 80, 2015. adsabs.harvard.edu.ezp-prod1.h … 015A%26A...575A..80P

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Tuxford
1 / 5 (6) Jun 22, 2015
reject suggestions that the AGN outflows will quench the star formation in such galaxies. Whatever the details of the growth feedback mechanism


Well it is a start that astronomers even understand the word feedback. As a controls systems engineer, this word is fundamental.

And the concept is also fundamental to the nature of the universe, starting with the sub-atomic particle. Starting there leads to the prediction that matter forms most rapidly deep within the cores of these monster core stars, with finite core densities, rather than infinite densities. And it leads to understanding that the universe did not start with a bang, and is not converging and diverging at the same time, and that new stars largely from material produced in the cores, and that the size of the core star is proportional to the size of the galaxy, naturally, and many other conclusions in line with recent observations.

It all starts with feedback.
Tuxford
1.3 / 5 (6) Jun 22, 2015
Collision models now suspect?

They also find that visible tidal features can be a misleading measure of an interaction - some AGN pairs may be interacting yet show no tidal features, perhaps because of the galaxy composition or details of the collision.


http://phys.org/n...tml#nRlv

And windy environment, with lots of new material ejected therefrom:

When the lines are seen, however, they reveal the presence of very fast motions in the wind, up to 2000 kilometers per second; there are as much as 200 million solar masses of material in these winds.


http://phys.org/n...tml#nRlv

And AGN more common than thought?

searches for other extreme AGN that neglect star-formation signatures are likely to miss a significant population of the most heavily obscured AGN


http://phys.org/n...tml#nRlv
cantdrive85
2.1 / 5 (7) Jun 22, 2015
"Tested" only against inference and assumption, as we know these things cannot be recreated in any kind of lab environ. Infinite densities and such only exist on paper and in the minds of fanciful mathematicians, regardless of how many "primary sources" one might like to link. Black holes, unicorns, and leprechauns are one in the same, fictional creations!
cantdrive85
1 / 5 (5) Jun 22, 2015
Yep, just as we cannot recreate a star, say, or a galaxy in the lab

We will see... Although your comment could not be any truer when referring to Eddington's/ST model of the Sol. Another unfalsifiable model (one of many) of the ST.

Yep, nothing to do with astropysics (sic)

Yep, nothing to do with anything whatsoever.

let's not forget to include stars powered by giant galactic Birkeland currents,

Birkeland currents have been directly measured. BH's? Not even close.

huge neutrino fluxes from fusion in/on the photosphere,

The neutrino problem is one of the ST, solved ad hoc and a posterior.
solid (silicate-based) rocks with densities less than that of water

Only in a universe in which gravity is the only significant phenomenon, such as the one you idolize and worship. In an Electric Universe the density of the rock is constant, gravity not so much depending upon the charge of the object.

Captain Stumpy
5 / 5 (3) Jun 22, 2015
Birkeland currents have been directly measured
@cd
by all means, please show the direct measurement of the Giant galactic Birkeland currents which are proven to power stars... because that is the context of the quote by Jean and you stated "Birkeland currents have been directly measured" in reply

that indicates that you have empirical evidence - and i've yet to see any legitimate papers supporting this conjecture gravity is the only significant phenomenon so you are saying you are not well versed in physics OR astrophysics (we already know you don't know anything about astrophysics because of prior comments about Astro's not knowing plasma physics despite it being in the curriculum for ALL astro's)
In an Electric Universe the density of the rock is constant
so that means iron ore is the same density as lead, or graphite or slate or corundum or diamond or carbon?

can you be more specific on that and give evidence supporting your conclusions?
Captain Stumpy
5 / 5 (3) Jun 23, 2015
@cd cont'd
In an Electric Universe blah blah blah charge of the object
let me get this straight... you are pulling a reg mundy? where is the evidence?

are you saying we can't see density well enough to differentiate it from a charge, or we can't measure either accurately enough on earth?

you claim that the issue of attraction in objects is due to the charge and NOT gravity... but this is easily measured, so this should be easily proven!
Where is the proof?

given your statement, we should be able to affect the path of even the moon with objects like our own CERN... but lets not go there for right now... where is the proof that charge differences affect any other object which we can readily measure and track- like the ISS or Roseta ? These things are heavily monitored, so there should be a readily available abundance of papers for you to link (not from eu and thunderbutts, but everywhere)

i can't wait to read all about it...

(sarc/hyperbole)
Captain Stumpy
5 / 5 (3) Jun 23, 2015
@cd
one last thing about your comment above
In an Electric Universe ...charge of the object
ok, how does it explain the following experiment shown by Brian Cox in a large vacuum?

https://www.youtu...-CfukEgs

this is particularly important because there is a large difference between the charges and capabilities of charge between the feathers and the bowling ball... the feather cannot hold or conduct near as much of a charge as the bowling ball can... and that is measurable and known...

you should perhaps publish a study on that, eh? Maybe you can get the vacuum chamber to add electrodes at each end to simulate charges in order to affect the experiment - that should show a huge difference if you are correct

(hyperbole/satire/sarc.)

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