Hi My Friends: A VUELO DE UN QUINDE EL BLOG., This galaxy cluster has been dubbed the "Phoenix Cluster" because it is
located in the constellation of the Phoenix, and because of its
remarkable properties, as explained here and in our press release. Stars
are forming in the Phoenix Cluster at the highest rate ever observed
for the middle of a galaxy cluster. The object is also the most powerful
producer of X-rays of any known cluster, and among the most massive of
clusters. The data also suggest that the rate of hot gas cooling in the
central regions of the cluster is the largest ever observed.
The Remarkable Phoenix Cluster
The image on the left shows the newly discovered Phoenix Cluster,
located about 5.7 billion light years from Earth. This composite
includes an X-ray image from NASA's Chandra X-ray Observatory in purple,
an optical image from the 4m Blanco telescope in red, green and blue,
and an ultraviolet (UV) image from NASA's Galaxy Evolution Explorer
(GALEX) in blue. The Chandra data reveal hot gas in the cluster and the
optical and UV images show galaxies in the cluster and in nearby parts
of the sky.
This galaxy
cluster has been dubbed the "Phoenix Cluster" because it is located in
the constellation of the Phoenix, and because of its remarkable
properties, as explained here and in our press release. Stars are
forming in the Phoenix Cluster at the highest rate ever observed for the
middle of a galaxy cluster. The object is also the most powerful
producer of X-rays of any known cluster, and among the most massive of
clusters. The data also suggest that the rate of hot gas cooling in the
central regions of the cluster is the largest ever observed.
Like other galaxy clusters, Phoenix contains a vast reservoir of hot gas
-- containing more normal matter than all of the galaxies in the
cluster combined -- that can only be detected with X-ray telescopes like
Chandra. This hot gas is giving off copious amounts of X-rays and
cooling quickly over time, especially near the center of the cluster,
causing gas to flow inwards and form huge numbers of stars.
These features of the central galaxy are shown in the artist's
illustration, with hot gas in red, cooler gas as blue, the gas flows
shown by the ribbon-like features and the newly formed stars in blue. An
animation [link to animation] shows the process of cooling and star
formation in action. A close-up of the middle of the optical and UV
image [link to optical/UV close-up] shows that the central galaxy has
much bluer colors than the nearby galaxies in the cluster, showing the
presence of large numbers of hot, massive stars forming.
These results are striking because most galaxy clusters have formed very
few stars over the last few billion years. Astronomers think that the
supermassive black hole in the central galaxy of clusters pumps energy
into the system. The famous Perseus Cluster is an example of a black
hole bellowing out energy and preventing the gas from cooling to form
stars at a high rate. Repeated outbursts from the black hole in the
center of Perseus, in the form of powerful jets, created giant cavities
and produced sound waves with an incredibly deep B-flat note 57 octaves
below middle C. Shock waves, akin to sonic booms in Earth's atmosphere,
and the very deep sound waves release energy into the gas in Perseus,
preventing most of it from cooling.
In the case of Phoenix, jets from the giant black hole in its central
galaxy are not powerful enough to prevent the cluster gas from cooling.
Correspondingly, any deep notes produced by the jets must be much weaker
than needed to prevent cooling and star formation.
Based on the Chandra data and also observations at other wavelengths,
the supermassive black hole in the central galaxy of Phoenix is growing
very quickly, at a rate of about 60 times the mass of the Sun every
year. This rate is unsustainable, because the black hole is already very
massive, with a mass of about 20 billion times the mass of the Sun.
Therefore, its growth spurt cannot last much longer than about a hundred
million years or it would become much bigger than its counterparts in
the nearby Universe. A similar argument applies to the growth of the
central galaxy. Eventually powerful jets should be produced by the black
hole in repeated outbursts, forming the deep notes seen in objects like
Perseus and stopping the starburst.
The Phoenix Cluster was originally detected by the South Pole Telescope,
using the Sunyaev-Zeldovich effect, as explained in more detail in a
blog interview [link to blog article] with the first author of the
paper, Michael McDonald. In a separate article we give more details
about the Sunyaev-Zeldovich effect, including a historical perspective,
in an interview [link to Chronicles article] with one of its
co-discoverers, Rashid Sunyaev.
The full author list of the Nature paper by Michael McDonald is: M.
McDonald, M. Bayliss, B. A. Benson, R. J. Foley, J. Ruel, P. Sullivan,
S. Veilleux, K. A. Aird, M. L. N. Ashby, M. Bautz, G. Bazin, L. E.
Bleem, M. Brodwin, J. E. Carlstrom, C. L. Chang, H. M. Cho, A.
Clocchiatti, T. M. Crawford, A. T. Crites, T. de Haan, S. Desai, M. A.
Dobbs, J. P. Dudley, E. Egami, W. R. Forman, G. P. Garmire, E. M.
George, M. D. Gladders, A. H. Gonzalez, N. W. Halverson, N. L.
Harrington, F. W. High, G. P. Holder, W. L. Holzapfel, S. Hoover, J. D.
Hrubes, C. Jones, M. Joy, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch,
J. Liu, M. Lueker, D. Luong-Van, A. Mantz, D. P. Marrone, J. J. McMahon,
J. Mehl, S. S. Meyer, E. D. Miller, L. Mocanu, J. J. Mohr, T. E.
Montroy, S. S. Murray, T. Natoli, S. Padin, T. Plagge, C. Pryke, T. D.
Rawle, C. L. Reichardt, A. Rest, M. Rex, J. E. Ruhl, B. R. Saliwanchik,
A. Saro, J. T. Sayre, K. K. Schaffer, L. Shaw, E. Shirokoff, R. Simcoe,
J. Song, H. G. Spieler, B. Stalder, Z. Staniszewski, A. A. Stark, K.
Story, C.W. Stubbs, R. Suhada, A. van Engelen, K. Vanderlinde, J. D.
Vieira, A. Vikhlinin, R.Williamson, O. Zahn, and A. Zenteno.
Credits: X-ray: NASA/CXC/MIT/M.McDonald; UV:
NASA/JPL-Caltech/M.McDonald; Optical: AURA/NOAO/CTIO/MIT/M.McDonald;
Illustration: NASA/CXC/M.Weiss
› Read more/access all images
› Chandra's Flickr photoset
Phoenix Cluster Sets Record Pace at Forming Stars
WASHINGTON
-- Astronomers have found an extraordinary galaxy cluster, one of the
largest objects in the universe, that is breaking several important
cosmic records. Observations of the Phoenix cluster with NASA's Chandra
X-ray Observatory, the National Science Foundation's South Pole
Telescope, and eight other world-class observatories may force
astronomers to rethink how these colossal structures and the galaxies
that inhabit them evolve.
Stars are forming in the Phoenix
cluster at the highest rate ever observed for the middle of a galaxy
cluster. The object also is the most powerful producer of X-rays of any
known cluster and among the most massive. The data also suggest the rate
of hot gas cooling in the central regions of the cluster is the largest
ever observed.
The Phoenix cluster is located about 5.7
billion light years from Earth. It is named not only for the
constellation in which it is located, but also for its remarkable
properties.
"While galaxies at the center of most clusters
may have been dormant for billions of years, the central galaxy in this
cluster seems to have come back to life with a new burst of star
formation," said Michael McDonald, a Hubble Fellow at the Massachusetts
Institute of Technology and the lead author of a paper appearing in the
Aug. 16 issue of the journal Nature. "The mythology of the Phoenix, a
bird rising from the dead, is a great way to describe this revived
object."
Like other galaxy clusters, Phoenix contains a vast
reservoir of hot gas, which itself holds more normal matter -- not dark
matter -- than all of the galaxies in the cluster combined. This
reservoir can be detected only with X-ray telescopes such as Chandra.
The prevailing wisdom once had been that this hot gas should cool over
time and sink to the galaxy at the center of the cluster, forming huge
numbers of stars. However, most galaxy clusters have formed very few
stars during the last few billion years. Astronomers think the
supermassive black hole in the central galaxy of a cluster pumps energy
into the system, preventing cooling of gas from causing a burst of star
formation.
The famous Perseus cluster is an example of a
black hole bellowing out energy and preventing the gas from cooling to
form stars at a high rate. Repeated outbursts in the form of powerful
jets from the black hole in the center of Perseus created giant cavities
and produced sound waves with an incredibly deep B-flat note 57 octaves
below middle C, which, in turn, keeps the gas hot.
"We
thought that these very deep sounds might be found in galaxy clusters
everywhere," said co-author Ryan Foley, a Clay Fellow at the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "The
Phoenix cluster is showing us this is not the case -- or at least there
are times the music essentially stops. Jets from the giant black hole at
the center of a cluster are apparently not powerful enough to prevent
the cluster gas from cooling."
With its black hole not
producing powerful enough jets, the center of the Phoenix cluster is
buzzing with stars that are forming about 20 times faster than in the
Perseus cluster. This rate is the highest seen in the center of a galaxy
cluster but not the highest seen anywhere in the universe. However,
other areas with the highest star formation rates, located outside
clusters, have rates only about twice as high.
The frenetic
pace of star birth and cooling of gas in the Phoenix cluster are causing
the galaxy and the black hole to add mass very quickly -- an important
phase the researchers predict will be relatively short-lived.
"The galaxy and its black hole are undergoing unsustainable growth,"
said co-author Bradford Benson, of the University of Chicago. "This
growth spurt can't last longer than about a hundred million years.
Otherwise, the galaxy and black hole would become much bigger than their
counterparts in the nearby universe."
Remarkably, the
Phoenix cluster and its central galaxy and supermassive black hole are
already among the most massive known objects of their type. Because of
their tremendous size, galaxy clusters are crucial objects for studying
cosmology and galaxy evolution, so finding one with such extreme
properties like the Phoenix cluster is important.
"This
spectacular star burst is a very significant discovery because it
suggests we have to rethink how the massive galaxies in the centers of
clusters grow," said Martin Rees of Cambridge University, a
world-renowned expert on cosmology who was not involved with the study.
"The cooling of hot gas might be a much more important source of stars
than previously thought."
The Phoenix cluster originally was
detected by the National Science Foundation's South Pole Telescope, and
later was observed in optical light by the Gemini Observatory, the
Blanco 4-meter telescope and Magellan telescope, all in Chile. The hot
gas and its rate of cooling were estimated from Chandra data. To measure
the star formation rate in the Phoenix cluster, several space-based
telescopes were used, including NASA's Wide-field Infrared Survey
Explorer and Galaxy Evolution Explorer and ESA's Herschel.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the
Chandra Program for NASA's Science Mission Directorate in Washington.
The Smithsonian Astrophysical Observatory controls Chandra's science and
flight operations from Cambridge, Mass.
For Chandra images, multimedia and related materials, visit:
For an additional interactive image, podcast, and video on the finding, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!
