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Lyman Alpha Blobs: Galaxies Coming of Age in Cosmic Blobs
Lyman Alpha Blobs

  • Using Chandra, growing supermassive black holes have been discovered in a sample of blobs, immense reservoirs of hydrogen gas located in the early Universe.

  • These black holes and bursts of star formation are believed to be illuminating and heating the gas in the blobs.

  • This represents a "coming of age" for the galaxies and black holes as they start to switch off their rapid growth.

A deep study of 29 gigantic blobs of hydrogen gas has been carried out with NASA's Chandra X-ray Observatory to identify the source of immense energy required to illuminate these structures. These mysterious blobs - called "Lyman-alpha blobs" by astronomers because of the light they emit - are several hundred thousand light years across and are seen when the Universe is only about two billion years old, or about 15% of its current age.

The composite image on the left shows one of the largest blobs observed in this study. Glowing hydrogen gas in the blob is shown by a Lyman-alpha optical image (colored yellow) from the National Astronomy Observatory of Japan's Subaru telescope. A galaxy located in the blob is visible in a broadband optical image (white) from the Hubble Space Telescope and an infrared image from the Spitzer Space Telescope (red). Finally, the Chandra X-ray Observatory image in blue shows evidence for a growing supermassive black hole in the center of the galaxy. Radiation and outflows from this active black hole are powerful enough to light up and heat the gas in the blob. Radiation and winds from rapid star formation occurring in the galaxy is believed to have similar effects. Clear evidence for four other active black holes in blobs is also seen.

The artist's representation on the right shows what one of the galaxies inside a blob might look like if viewed at a relatively close distance. A two-sided outflow powered by the supermassive black hole buried inside the middle of the galaxy is shown in bright yellow, above and below the spiral arms of the galaxy. This outflow illuminates and heats gas surrounding the galaxy. Radiation from regions close to the black hole will also play a significant role in lighting up and heating the blob. Stars are forming at a rapid rate in this galaxy, and young stars are being destroyed in supernova explosions. The three bright stars above the central bulge of the galaxy are examples of such supernovas (a companion illustration shows the effects of such explosions).

These new results show how blobs fit into the cosmic story of how galaxies and black holes evolve. Galaxies are believed to form when gas flows inwards under the pull of gravity and cools by emitting radiation. This process should stop when the gas is heated by radiation and outflows from galaxies and their black holes. Blobs could be a sign of this first stage, or of the second.

Based on the new data and theoretical arguments, Geach and his colleagues show that heating of gas by growing supermassive black holes and bursts of star formation, rather than cooling of gas, most likely powers the blobs. The implication is that blobs represent a stage when the galaxies and black holes are just starting to switch off their rapid growth because of these heating processes. This is a crucial stage of the evolution of galaxies and black holes -- known as "feedback" -- and one that astronomers have long been trying to understand.

Fast Facts for Lyman Alpha Blobs:
Credit  Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss
Release Date  June 24, 2009
Scale  Left panel is 38 arcsec across
Category  Cosmology/Deep Fields/X-ray Background
Coordinates (J2000)  RA | Dec
Constellation  Aquarius
Observation Date  08/01/2007 - 12/30/2007
Observation Time  4 days 15 hours
Obs. ID  8034-8036, 9717
Instrument  ACIS
References J. Geach et al. 2009, ApJ, in press
Color Code  X-ray (Blue); Optical (White, Yellow); Infrared (Red)
Distance Estimate  About 11.5 billion light years
distance arrow
Visitor Comments (24)

The actual cause of geometrical structure in this is oscillations between two different confocal oblate spheroids.

Posted by Anil Thanvi on Thursday, 06.20.13 @ 20:47pm

I am interested in how these objects are imaged via spectroscopy and telescope. Second in which direction these objects lie? and lastly is there a catalog for these object for the general public to access.

Thanking you in advance.

Posted by graham sing on Monday, 08.20.12 @ 19:33pm

What a fantastic site and for all the illuminating information on galaxy creation and their relationships to black holes. Has Chandra been able to locate galaxies blobs farther than 11.5 billion light years? We're almost witnessing the beginning of the universe anyway at such distances, but how wonderful to see at 13 billion light years.

Posted by Christopher Harper on Tuesday, 10.5.10 @ 19:49pm

I am really enjoying reading your well written articles.

Posted by prozestra on Friday, 07.2.10 @ 04:55am

I am really enjoying reading your well written articles. It looks like you spend a lot of effort and time on your blog.

Posted by prozestra on Friday, 07.2.10 @ 04:55am

Is there a map showing the location of Lyman alpha blobs with respect to the celestial equator?
Marvin Glover

Posted by marvin Glover on Wednesday, 11.18.09 @ 14:17pm

Dear Marvin,
Thanks for your question. Lyman-alpha blobs were first discovered about
ten years ago. This paper gives some references to the early work in the

Use this web-site to search for free copies of the various papers.
-P.Edmonds for CXC

Posted by P. Edmonds on Tuesday, 11.10.09 @ 11:23am

Can you tell me when Lyman-Alpha blobs were first discovered and is there any literature about how they were discovered?

Posted by Marvin Glover on Friday, 11.6.09 @ 17:59pm

I thank you for taking me out of my own, sometimes frustrating, medical research into a new world of wonder and beauty.

Posted by dr. sj robinson on Monday, 10.5.09 @ 08:51am

This paper tells me a lot of things about cosmic.
Thanks very much.

Posted by Hz on Thursday, 08.20.09 @ 23:03pm is the best. Keep it going. Have a nice day.

Posted by Tania on Tuesday, 07.14.09 @ 09:14am


Thanks for your question. Black holes are incredible objects, but the
evidence for a massive black hole in the center of our galaxy is very
strong and based on multiple lines of evidence. There is also very strong
evidence for smaller black holes with masses of about ten times the mass of the Sun. Please explore our field guide for more information about black
-P.Edmonds for CXC

Posted by P. Edmonds on Wednesday, 07.8.09 @ 12:14pm

Garth Barber:

Thanks for your compliments on the artist's impression. The redshift is
3.09. At this high redshift there is very limited information about
metallicity and the authors do not make any estimates in this latest
-P.Edmonds for CXC

Posted by P. Edmonds on Wednesday, 07.8.09 @ 12:10pm

Thank you very much for these marvel photos and to all the staff behind this job.

Posted by Fakhri H Ibrahim on Thursday, 07.2.09 @ 05:42am

What is the red shift of this object? What metallicity is observed? A remarkable artists impression on the right, thank you.

Posted by Garth Barber on Thursday, 07.2.09 @ 03:21am

In the atomic structure of matter there is a nucleus that matter centers around in the earliest stages of galactic formation gas is pulled to the center of what. It is hard for me to imagine matter being pulled to the center of nothing. Is there such a thing as a Black Hole or is the center of the galaxy something else like heavy-matter that creates a hub of a wheel that all ordinary matter spins around through its gravitational vortex? I feel that there is a piece of the puzzle that is missing from the equation like what could be so heavy that it could create enough gravity that would pull all matter to itself and be the creator of galaxies and the universe.

Posted by kristianna on Wednesday, 07.1.09 @ 22:01pm

Thank you for the tour of the universe, a truly magnificent journey it continues to be.

Posted by Craig on Wednesday, 07.1.09 @ 21:15pm

The continued search into our roots generates even more questions. The pictorial journey above by Chandra enlightens while simultaneously dazzling us. We are only 2 billion years of the past light away from our earliest conception. However, now I understand how a black hole can develop so quickly after creation of the Universe. KEEP UP THE GREAT WORK.

Posted by Roger Parkhurst on Tuesday, 06.30.09 @ 23:27pm

Very informative. Fantastic pictures.

Posted by don nott on Saturday, 06.27.09 @ 11:48am

Is really amazing how much we approach to the first steps of the formations of galaxies and black holes, some day the science will be capable of to unveil completely to this secrets and will prove finally the important role that play the black holes in the formations of the galaxies and much of this we will have to thanks to the people of Chandra, for the great job they are doing to contribute to many discovery like that.

Posted by Donis Gárciga on Friday, 06.26.09 @ 11:10am

So good to learn about, thanks a lot.

Posted by Angela on Thursday, 06.25.09 @ 14:34pm

Chandra has done fabulous job, providing clues on galaxy formation.
Bravo, keep going on.
Thanks again for the wonderful job, you people are doing.

Posted by dr ghanz patel on Thursday, 06.25.09 @ 13:45pm

Excelent brilliant. thanks a lot.

Posted by Jose Ovidio on Thursday, 06.25.09 @ 12:32pm

Fantastic, Many thanks.

Posted by Dr S Ranga Sreenivasan on Thursday, 06.25.09 @ 08:45am

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