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Quasars' Awesome Power Found to Extend to Outer Limits of Galaxies




Quasars are among the brightest, oldest, most distant, and most powerful objects in the universe. Powered by massive black holes at the center of most known galaxies, quasars can emit enormous amounts of energy, up to a thousand times the total output of the hundreds of billions of stars in our entire Milky Way. Dartmouth astrophysicists Ryan Hickox and Kevin Hainline and colleagues have a paper scheduled for publication in The Astrophysical Journal, detailing discoveries based upon observations of 10 quasars in which they document the immense power of quasar radiation, which reaches out for many thousands of light years to the limits of the quasar's galaxy.

"For the first time, we are able to see the actual extent to which these quasars and their black holes can affect their galaxies, and we see that it is limited only by the amount of gas in the galaxy," says Hainline, a Dartmouth postdoctoral research associate. "The radiation excites gas all the way to the margins of the galaxy and stops only when it runs out of gas."

The radiation released by a quasar covers the entire electromagnetic spectrum, from radio waves and microwaves at the low-frequency end through infrared, ultraviolet, and X-rays, to high-frequency gamma rays. A central black hole, also called an active galactic nucleus, may grow by swallowing material from the surrounding interstellar gas, releasing energy in the process. This leads to the creation of a quasar, emitting radiation that illuminates the gas present throughout the galaxy. 

The image below shows galaxy NGC 7319 The small object indicated by the arrow is a quasar. 


            NGC7319quasarLabeled (1)

"If you take this powerful, bright radiation source in the center of the galaxy and blast the gas with its radiation, it will get excited in just the same way the neon gets excited in neon lamps, producing light," says Hickox, an assistant professor in the Department of Physics and Astronomy at Dartmouth. "The gas will produce very specific frequencies of light that only a quasar can produce. This light functioned as a tracer that we were able to use to follow the gas excited by the black hole out to large distances."

Quasars are small compared to a galaxy, like a grain of sand on a beach, but the power of their radiation can extend to the galactic boundaries and beyond.

The illumination of gas can have a profound effect, since gas that is lit up and heated by the quasar is less able to collapse under its own gravity and form new stars. Thus, the tiny central black hole and its quasar can slow down star formation in the entire galaxy and influence how the galaxy grows and changes over time.

"This is exciting because we know from a number of different independent arguments that these quasars have a profound effect on the galaxies in which they live," Hickox says. "There is a lot of controversy about how they actually influence the galaxy, but now we have one aspect of the interaction that can extend on the scale of the entire galaxy. Nobody had seen this before."

Hickox, Hainline, and their co-authors based their conclusions on observations made with the Southern African Large Telescope (SALT), the largest optical telescope in the southern hemisphere. Dartmouth is a partner in SALT, giving faculty and students access to the instrument. The observations were performed using spectroscopy, in which light is broken down into its component wavelengths. "For this particular kind of experiment, it is among the best telescopes in the world," says Hickox.

They also used data from NASA's Wide-field Infrared Survey Explorer (WISE) -- a space telescope that imaged the whole sky in the infrared. The scientists used observations in infrared light because they give a particularly reliable measure of the total energy output by the quasar.

The Daily Galaxy via Dartmouth College and Joseph Blumberg

Image credits: and


Does the outward galactic radiation pressure from quasars suggest there might be an extremely large quasar that is accelerating our observable universe but is ‘hidden’ by interstellar dust? Is this hidden body the source of dark energy?

I didn't understand this because the link of black holes to quasars was new to me so I wiki'd it for a bit more info and found this: ULAS J1120+0641, with a redshift of 7.085, which corresponds to a proper distance of approximately 29 billion light-years from Earth (see more discussion of how cosmological distances can be greater than the light-travel time at Metric Expansion of Space).

Now I'm thoroughly confused because I don't understand how if the Universe is estimated to be 13 billion years old can something be 29 billion light years from earth.

@resonaz No, this is not possible. The radiation feedback could possibly regulate the evolution of a galaxy. @Simon Redshift of 7 is appr. 13 billion light years, shortly after the universe was created and redshift accounts for universe expansion as well.

Thank you d. I think this is all just beyond me and the sizes, distances and time just to great to comprehend.

Something can be 29 billion light years from earth because we are moving away from each other in opposite(ish) directions at a relative speed nearing the speed of light.

The error is in measurement techniques. Nothing ise further away than the partial diameter of the universe from Earth, measured in light years from the beginning "big bang" or whatchamacallit. I say "partial" for we are not on the extreme horizon of the universe observing the other extreme horizon in the opposite "direction", we're somewhere inside it (no one is quite sure where exactly we are for the universe hasn't been mapped yet.) There are confliting writings on just how old the universe is in terms of Earth years.

Off subject....universe expansion

Also, since the universe is expanding supposedly at the speed of light then anything that is on the horizon is just under the speed of light reference the 'center' of the universe and anything equalling C at the exact horizon either turns into pure energy of some sort (or an all inclusive spectrum of photons) and therefore doesn't exist as matter (supposedly agreeing with Einstein) OR it is possible for matter to exceed the speed of light BEYOND the universe horizon...which in itself is contradictory since ALL matter is the universe, inside or outside the horizon...which is also contradictory for a horizon implies the "edge" of the universe itself and the term "outside" the horizon is impossible. Edge? Well, that's in a way contradictory in that an "edge" implies something beyond or it would not be an "edge". See where this gets hairy?

Now, if everything exceeding C at the very horizon of the universe turns into energy, where is the energy going? It isn't going back to us so we can see it or is it? Do we see it? No. Why? Because it doesn't work like that and we don't know how it works either.

But here's a clue. If mass turns into energy, say photons, going away from us at the speed of light then the doppler effect completely flatens out the wave form of the photons so they are essentially invisable and/or never reach us. If a plane is going 3000 ft/second and shoots a bullet backwards at 3000 ft/second relative to the gun's muzzle, it has 0 velocity from a ground viewer and drops out of the air straight down, I hope you can understand this simple concept. Likewise a mass going speed C emits a photon (bullet) backwards going at speed C, it's null. Therefore we can't see a thing happening on the universe's horizon for there are no photons of any sort reaching us and without photons we're lost in the dark.

At this point mankind has approached his/her limit of undestanding of exactly what the universe is, where it's horizon is and what happens there, what formed it, and mankind had better accept the fact that all matter is just compacted energy packets and that the universe is essentially ALL energy, compact or not. You can call it "dark", "regular" or well done for that matter. Pun intended. If you break down an atom all the way you get packets of energy which are labled by man as "particles" (for want of a better word in English anyway) and these ultimate particles have no mass in themselves. These are the building blocks of quarks. They are "made" of energy. This gets hairy again. When they combine to form quarks and the quarks form sub atomic particles, about then does mass exist (hence then and only then does gravity exist since gravity is a function of mass's effect on time/space.

It gets pretty hairy for a beginning physics student and it's pretty hairy for me, a lifetime study of physics. Then there are the string theorists who claim strings occur of singularity in giant arcs throughout the universe to complicate matters worse. Actually we don't know our arcs from a black hole in the ground and we, as Einstein said, see the universe as a giant illusion, it's not at all what we think we see at all. Even a high school chemistry student knows we are mostly empty space...the actual volume of an atom consists of a huge space between the nucleus and the electron orbitals and an orbital is only open space inhabited with one lone teentsy bitsy sociopath electron which behaves more as a wave form than even a particle. So the atoms we and everything are made from is basically empty space with an almost immeasurably small amount of particles zipping through it. Fish occupy more space in an ocean proportionately than subatomic particles occupy in an atom.

It stands to reason a large star can collapse to something the size of a pin head...actrually not into matter at all but compact energy which represents itself in a gravity foot print on space/time, as if it reminds us of the huge amount of energy needed to form even a tick fece speck of matter. If a tick fece were to be instantly converted to energy, it would incinerate a city block.

off the subject but interesting...and this explains why quasars are so powerful, converting matter into energy constantly and jetisoning it out again in the form of "emissions", i.e. matter jets + energy in constant mini big bang mode.

1 gram of matter = a 100 watt light bulbs burning for 30,000 years. That's what you would get if you had a matter/antimatter energy provider device like in Star Treck...a half gram of matter + a half gram of antimatter = 1 gram total conversion to energy, or 30,000 years of light from a 100 watt bulb or in watts per second, do the math...multiply 30,000 years X 100 watts X 365days/year X 24hrs/day X 60minutes/hr X 60seconds/minute (94.6 trillion watts) released in one second (94.6 trillion watt seconds)from 1 gram of matter using E=mC2, which would fry a lot of realestate and really ruin someone's day. In turn a kiloton bomb yield = 4,184,000,000,000 (4 thousand 184 trillion watt seconds) per calculator on page so a gram of matter is pretty hot stuff if converted into pure energy, say infrared photons, about 2.3% of a kiloton = 22 tons of TNT equivalent...that's a pretty big boom from a gram of matter. Thats about what the Davy Crocket nuclear device yielded... and remember this would also be the yield of 1 gram of matter converted to energy in 1 second.

Strange beasts these quasars,there not moving away from us nor are they coming towards us.its like as though dropped into pre existing holes in the fabric of space.

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