Emerging Supermassive Black Holes Choke Star Formation

Article written: 27 Jan , 2012
Updated: 24 Dec , 2015
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Located on the Chajnantor plateau in the foothills of the Chilean Andes, ESO’s APEX telescope has been busy looking into deep, deep space. Recently a group of astronomers released their findings regarding massive galaxies in connection with extreme times of star formation in the early Universe. What they found was a sharp cut-off point in stellar creation, leaving “massive – but passive – galaxies” filled with mature stars. What could cause such a scenario? Try the materialization of a supermassive black hole…

By integrating data taken with the LABOCA camera on the ESO-operated 12-metre Atacama Pathfinder Experiment (APEX) telescope with measurements made with ESO’s Very Large Telescope, NASA’s Spitzer Space Telescope and other facilities, astronomers were able to observe the relationship of bright, distant galaxies where they form into clusters. They found that the density of the population plays a major role – the tighter the grouping, the more massive the dark matter halo. These findings are the considered the most accurate made so far for this galaxy type.

Located about 10 billion light years away, these submillimetre galaxies were once home to starburst events – a time of intense formation. By obtaining estimations of dark matter halos and combining that information with computer modeling, scientists are able to hypothesize how the halos expanding with time. Eventually these once active galaxies settled down to form giant ellipticals – the most massive type known.

“This is the first time that we’ve been able to show this clear link between the most energetic starbursting galaxies in the early Universe, and the most massive galaxies in the present day,” says team leader Ryan Hickox of Dartmouth College, USA and Durham University, UK.

However, that’s not all the new observations have uncovered. Right now there’s speculation the starburst activity may have only lasted around 100 million years. While this is a very short period of cosmological time, this massive galactic function was once capable of producing double the amount of stars. Why it should end so suddenly is a puzzle that astronomers are eager to understand.

“We know that massive elliptical galaxies stopped producing stars rather suddenly a long time ago, and are now passive. And scientists are wondering what could possibly be powerful enough to shut down an entire galaxy’s starburst,” says team member Julie Wardlow of the University of California at Irvine, USA and Durham University, UK.

Right now the team’s findings are offering up a new solution. Perhaps at one point in cosmic history, starburst galaxies may have clustered together similar to quasars… locating themselves in the same dark matter halos. As one of the most kinetic forces in our Universe, quasars release intense radiation which is reasoned to be fostered by central black holes. This new evidence suggests intense starburst activity also empowers the quasar by supplying copious amounts of material to the black hole. In response, the quasar then releases a surge of energy which could eradicate the galaxy’s leftover gases. Without this elemental fuel, stars can no longer form and the galaxy growth comes to a halt.

“In short, the galaxies’ glory days of intense star formation also doom them by feeding the giant black hole at their centre, which then rapidly blows away or destroys the star-forming clouds,” explains team member David Alexander from Durham University, UK.

Original Story Source: European Southern Observatory News. For Further Reading: Research Paper Link.

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9 Responses

  1. Anonymous says

    It is interesting that SMBH activity would suppress star forming or starbust activity. I had been under the impression just the opposite was the case. The formation of a black hole entails a certain percentage of material being ejected outwards. For an average black hole the supernova explosion ejects half or so of the stellar material outwards. The formation of a SMBH similarly ejects material outwards. It has been be reckoning that such material flying outwards exerted pressure on nebular material in a galaxy and caused star formation. Yet if I understand this it means the formation of large SMBHs is such that gas in a galaxy is ejected outwards, which leads to a paucity of later star formation.

    LC

    • caleb lloyd says

      While your statement is partially correct, I read that some black holes can be formed by a dying star without exploding into a nova, therefore there would be less star-burst activity than around the average black hole.

      • Anonymous says

        That can happen with very massive stars, such as for M = 100M_{sol} or larger. The extreme energy condition in the core begin to generate e-e^+ pairs which increases the number of degrees of freedom. The energy E = CT may increase as the heat capacity C = C(N) increases as the number of degrees of freedom increases. The temperature may then remain constant or maybe decrease. In this case a huge star can implode into a black hole with hardly a whimper. This is though a rather exceptional situation.

        LC

  2. Member
    Steve Nerlich says

    This analysis seems to step around a lot of established galaxy formation theory. An elliptical galaxy is generally considered to be very old – essentially the end point of galaxy evolution (that might start with a bright, starburst spiral galaxy) – so most of the free gas has already been exhausted by eons of star formation.

    And generally in galaxies with free gas a dynamic outburst (like a supernova) is thought to stimulate star formation – but here it ‘eradicates’ any free gas??

    • Torbjörn Larsson says

      I don’t know about stepping around, offering an alternative pathway perhaps. I thought it was pretty established by now that SMBH jets controlled star formation, explaining some of the feedbacks observed. (IIRC, in the form of steady star formation rates at later times.)

      The exciting thing IMHO would be if, yet again, dark matter is needed to predict observations.

      From the paper:

      “This prediction is consistent with previous suggestions based on the dynamical (Swinbank et al. 2006) and stellar masses (e.g. Hainline et al. 2011) of SMGs, and is also consistent with observations of local massive ellipticals, which indicate that they formed the bulk of their stars at z > 2 and have been largely passive since.” [My bold.]

      Just browsing, but the fig 7 shows a nice trajectory for DM halo vs age, with the ellipticals as the mature endpoint.

      Is DM becoming the new magnetic field Swiss army knife? Or is it an indelible part of standard cosmology and especially large structure formation? I think the later.

      • Anonymous says

        The rapid formation of a large SMBH will eject lots of material rapidly on galactic time scales. These shock fronts should induce lots of star burst activity, but may also eject lots of gas and dust from the inner regions of the galaxy or into intergalactic space. This might then reduce future star formation.

        The Milky Way and Andromeda are headed for a “tango” and coalescence starting in 2 to 2-1/2. billion years. This will likely result in massive activity, the two BHs in the galaxies will likely coalesce in the future and there may be some starburst activity over the preceding billion years or so. The Andromway galaxy that results will then probably settle into staid activity. I suppose the long term future for star formation is the red dwarf, which may form more slowly, exist much longer and fade out in cooler nova events.

        It is interesting how time scales keep expanding. The inflationary period occurred about 10^{-32} seconds into the early universe and lasted only 10^{-35}seconds. This lead to the reheating of the universe which broke the GUT symmetry. The electroweak gauge system persisted up to about 3 seconds into the universe, and QCD transitioned from a plasma state to confinement. There was then a QED phase for three minutes, which ended and this lead to a radiation dominate period for 380,000 years, then the matter dominated phase and darkness which saw PopIII stars and galaxy formation in a few hundred million years, then … . The clock is ticking off longer time periods for fundamental events, and this will continue into the future, where protons will all decay away in 10^{40} years and eventually there will be huge trillion M_{sol} SMBHs in the cosmic horizon for 10^{120} years. Beyond that is Hawking-Gibbon radiation and the decay of the de Sitter vacuum over a far larger time period. Time itself seems to be breaking down.

        LC

    • Torbjörn Larsson says

      For fun, I just stumbled on research that may combine DM and magnetic fields. Egad!

      “In galaxy formation models, a gravitational nucleus is formed out of cold dark matter. Ordinary matter in the form of gas collects around the nucleus and, as it collapses, it heats up. The relatively rapid gravitational collapse sends shock waves through the gas, blowing some of it away from the protogalaxy, but driving star formation in the process. (A shock wave is a wave that travels faster than the speed of sound in a material, as with a sonic boom.)

      Because this formation is happening on a large physical scale (since galaxies are on the scale of tens or hundreds of thousands of light-years across), some parts of the protogalaxy will be more dense than others, which means the shock waves will be unevenly distributed. The ionizing effect of the shocks strips atoms of their electrons; the accelerating charged particles then produce magnetic fields. This process is known as the Biermann battery. […]

      Relating the experimental results back to astronomy involves dramatic rescaling. The time-frame goes from a few nanoseconds in the lab to approximately 700 million years for gravitational collapse, and the relatively high magnetic field strength in the lab (from the large number of electrons in a small space) subsequently becomes much smaller. By using standard scaling formulas, the magnetic fields observed correspond to each other—a dramatic confirmation that non-spherical shock waves during galaxy formation are indeed the source of the galactic magnetic fields we’ve observed.”

    • Torbjörn Larsson says

      For fun, I just stumbled on research that may combine DM and magnetic fields. Egad!

      “In galaxy formation models, a gravitational nucleus is formed out of cold dark matter. Ordinary matter in the form of gas collects around the nucleus and, as it collapses, it heats up. The relatively rapid gravitational collapse sends shock waves through the gas, blowing some of it away from the protogalaxy, but driving star formation in the process. (A shock wave is a wave that travels faster than the speed of sound in a material, as with a sonic boom.)

      Because this formation is happening on a large physical scale (since galaxies are on the scale of tens or hundreds of thousands of light-years across), some parts of the protogalaxy will be more dense than others, which means the shock waves will be unevenly distributed. The ionizing effect of the shocks strips atoms of their electrons; the accelerating charged particles then produce magnetic fields. This process is known as the Biermann battery. […]

      Relating the experimental results back to astronomy involves dramatic rescaling. The time-frame goes from a few nanoseconds in the lab to approximately 700 million years for gravitational collapse, and the relatively high magnetic field strength in the lab (from the large number of electrons in a small space) subsequently becomes much smaller. By using standard scaling formulas, the magnetic fields observed correspond to each other—a dramatic confirmation that non-spherical shock waves during galaxy formation are indeed the source of the galactic magnetic fields we’ve observed.”

      • Anonymous says

        This is interesting. I am not sure if the time scales work though. The pulse time in in the nanosecond range, while the size of these carbon elements is in the millimeter range. The time for a photon to cross that is 10^{-11} sec. So the photon shock propagates information across the system more or less at the same spread in time.

        LC

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