* Astronomy

Blobrana · L

RE: SMM J1237+6203

Blobrana · L

'Catastrophic event' halted development of galaxy

Scientists have found evidence of a catastrophic event they believe was responsible for halting the birth of stars in a galaxy in the early Universe.
The researchers, led by Durham Universitys Department of Physics, observed the massive galaxy as it would have appeared just three billion years after the Big Bang when the Universe was a quarter of its present age.
According to their findings the galaxy exploded in a series of blasts trillions of times more powerful than any caused by an atomic bomb. The blasts happened every second for millions of years, the scientists said.
The explosions scattered the gas needed to form new stars by helping it escape the gravitational pull of the galaxy called SMM J1237+6203, effectively regulating its growth, the scientists added.
They believe the huge surge of energy was caused by either the outflow of debris from the galaxy's black hole or from powerful winds generated by dying stars called supernovae.
The research, funded by the Royal Society and the Royal Astronomical
Society, is published in the Monthly Notices of the Royal Astronomical Society.
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Title: Revealing an Energetic Galaxy-Wide Outflow in a z~2 Ultraluminous Infrared Galaxy
Authors: D.M. Alexander (Durham), A.M. Swinbank, I. Smail, R. McDermid, N.P.H. Nesvadba

Leading models of galaxy formation require large-scale energetic outflows to regulate the growth of distant galaxies and their central black holes. However, current observational support for this hypothesis at high redshift is mostly limited to rare z>2 radio galaxies. Here we present Gemini-North NIFS Intregral Field Unit (IFU) observations of the [O III]5007 emission from a z~2 ultraluminous infrared galaxy (ULIRG; L_IR>10^12 L_sol) with an optically identified Active Galactic Nucleus (AGN). The spatial extent (~4-8 kpc) of the high velocity and broad [O III] emission are consistent with that found in z>2 radio galaxies, indicating the presence of a large-scale energetic outflow in a galaxy population potentially orders of magnitude more common than distant radio galaxies. The low radio luminosity of this system indicates that radio-bright jets are unlikely to be responsible for driving the outflow. However, the estimated energy input required to produce the large-scale outflow signatures (of order ~10^59 ergs over ~30 Myrs) could be delivered by a wind radiatively driven by the AGN and/or supernovae winds from intense star formation. The energy injection required to drive the outflow is comparable to the estimated binding energy of the galaxy spheroid, suggesting that it can have a significant impact on the evolution of the galaxy. We argue that the outflow observed in this system is likely to be comparatively typical of the high-redshift ULIRG population and discuss the implications of these observations for galaxy formation models.

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Black Hole May Fuel Galactic Mass Exodus

Consequences of galaxy-scale outflows are profound in the early universe, and an international team led by David Alexander at Durham University (UK) provides insight into the process using new observations with the Gemini Near-Infrared Integral Field Spectrometer (NIFS) on Gemini North.
The material between galaxies is observed to be enriched in metals (elements more complex than helium) compared with primordial abundances, which requires early generations of star formation to produce the metals. The galactic outflows thought to be responsible for this enrichment must be extremely energetic for the material to escape a galaxys strong gravitational pull.
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