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Post Info TOPIC: Ly-alpha Blobs
Blobrana


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SSA 22
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Ancestors of  present day galaxies


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Blobrana


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Posts: 131433
Date:
Objects in Early Universe
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Secrets of Objects in Early Universe
The true nature of mysterious objects in the early universe will be revealed during a media teleconference on Wednesday June 24, 1:30 p.m. EDT. The results were made using NASA's Chandra X-ray Observatory and other telescopes. Sir Martin Rees will serve as an independent commentator in the press conference and will discuss the significance of these findings.

The press conference will be broadcast via a live audio stream

-- Edited by Blobrana on Wednesday 24th of June 2009 05:45:59 PM

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Blobrana


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Himiko
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Astronomers on Wednesday announced the discovery of a massive and mysterious gas blob of the type that can be precursors to galaxies, which they dubbed Himiko.
The data used in identifying the megablob came from a suite of telescopes. Scientists said the object, which they named Himiko for the legendary Japanese queen, existed when our universe was only about 800 million years old.

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Blobrana


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Lyman-alpha blobs
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Using some of the biggest telescopes in the world, astronomers have discovered a huge, amorphous cloud of hot hydrogen gas that was glowing when the Universe was just 800 million years old.

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Blobrana


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RE: Ly-alpha Blobs
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Mysterious Space Blob Discovered at Cosmic Dawn



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Blobrana


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Lyman-alpha blob
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A strange giant space "blob" spotted when the universe was relatively young has got astronomers puzzled.
Using space and ground telescopes, astronomers looked back to when the universe was only 800 million years old and found something that was out of proportion and out of time. It was gaseous, big, and emitted a certain type of radiation, said study lead author Masami Ouchi, an astronomer at the Carnegie Observatories in Pasadena, Calif.

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Blobrana


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RE: Ly-alpha Blobs
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It might not look like much, but this image represents one of the most distant objects astronomers have ever seen, 12.9 billion light years away.
It is a "Lyman-alpha blob" and is 55,000 light years across - as large as present-day galaxies.

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Blobrana


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Using some of the biggest telescopes in the world, astronomers have discovered a huge, amorphous cloud of hot hydrogen gas that was glowing when the Universe was just 800 million years old.
The cloud - called a blob - may be collapsing, fuelling the birth of new stars that lie within but are obscured by the cloud. If so, the blob would be a rare glimpse of galaxy formation in action 12.9 billion years ago, in the Universe's infancy. But the blob - which the astronomers named Himiko after a legendary Japanese queen - is no baby. It is at least half the size of the Milky Way - big enough to fly in the face of standard theories of galaxy formation, which propose that galaxies grow slowly over time through the merger of smaller building blocks.

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Blobrana


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Title: The Chandra Deep Protocluster Survey: Ly-alpha Blobs are powered by heating, not cooling
Authors: J. E. Geach (1), D. M. Alexander (1), B. D. Lehmer (1), Ian Smail (1), Y. Matsuda (1), S. C. Chapman (2), C. A. Scharf (3), R. J. Ivison (4), M. Volonteri (5), T. Yamada (6), A. W. Blain (7), R. G. Bower (1), F. E. Bauer (3), A. Basu-Zych (3) ((1) Durham, (2) IoA Cambridge/Victoria, (3) Columbia, (4) SUPA/ATC Edinburgh, (5) Michigan Ann Arbor, (6) NAOJ, (7) Caltech)
(Version v2)

We present the results of a 400ks Chandra survey of 29 extended Ly-alpha emitting nebulae (Ly-alpha Blobs, LABs) in the z=3.09 proto-cluster in the SSA22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction of active galactic nuclei (AGN) in LABs, f_AGN = 17% down to L_2-32keV ~ 10^44 erg/s. All of the AGN appear to be heavily obscured, with spectral indices implying obscuring column densities of N_H > 10^23 cm^-2. The AGN fraction should be considered a lower limit, since several more LABs not detected with Chandra show AGN signatures in their mid-infrared emission. We show that the UV luminosities of the AGN are easily capable of powering the extended Ly-alpha emission via photo-ionisation alone. When combined with the UV flux from a starburst component, and energy deposited by mechanical feedback, we demonstrate that 'heating' by a central source, rather than gravitational cooling is the most likely power source of LABs. We argue that all LABs could be powered in this manner, but that the luminous host galaxies are often just below the sensitivity limits of current instrumentation, or are heavily obscured. No individual LABs show evidence for extended X-ray emission, and a stack equivalent to a >9Ms exposure of an average LAB also yields no statistical detection of a diffuse X-ray component. The resulting diffuse X-ray/Ly-alpha luminosity limit implies there is no hot (T>10^7 K) gas component in these halos, and also rules out inverse Compton scattering of cosmic microwave background photons, or local far-infrared photons, as a viable power source for LABs.

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