Mostrando entradas con la etiqueta The constellation Virgo. Mostrar todas las entradas
Mostrando entradas con la etiqueta The constellation Virgo. Mostrar todas las entradas

jueves, 22 de agosto de 2013

NASA - NASA's Fermi Celebrates Five Years in Space, Enters Extended Mission

During its five-year primary mission, NASA's Fermi Gamma-ray Space Telescope has given astronomers an increasingly detailed portrait of the universe's most extraordinary phenomena, from giant black holes in the hearts of distant galaxies to thunderstorms on Earth.
But its job is not done yet. On Aug. 11, Fermi entered an extended phase of its mission -- a deeper study of the high-energy cosmos. This is a significant step toward the science team's planned goal of a decade of observations, ending in 2018.
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From blazars to thunderstorms, this video showcases highlights from the Fermi Gamma-ray Space Telescope's first five years in space.
Image Credit: NASA’s Goddard Space Flight Center
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"As Fermi opens its second act, both the spacecraft and its instruments remain in top-notch condition and the mission is delivering outstanding science," said Paul Hertz, director of NASA's astrophysics division in Washington.
Fermi has revolutionized our view of the universe in gamma rays, the most energetic form of light. The observatory's findings include new insights into many high-energy processes, from rapidly rotating neutron stars, also known as pulsars, within our own galaxy, to jets powered by supermassive black holes in far-away young galaxies.
The Large Area Telescope (LAT), the mission's main instrument, scans the entire sky every three hours. The state-of-the-art detector has sharper vision, a wider field of view, and covers a broader energy range than any similar instrument previously flown.
"As the LAT builds up an increasingly detailed picture of the gamma-ray sky, it simultaneously reveals how dynamic the universe is at these energies," said Peter Michelson, the instrument's principal investigator and a professor of physics at Stanford University in California.
Fermi's secondary instrument, the Gamma-ray Burst Monitor (GBM), sees all of the sky at any instant, except the portion blocked by Earth. This all-sky coverage lets Fermi detect more gamma-ray bursts, and over a broader energy range, than any other mission. These explosions, the most powerful in the universe, are thought to accompany the birth of new stellar-mass black holes.
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Fermi's portrait of the sky at energies beyond 1 GeV has steadily deepened with more data. This animation compares views of a 20-degree-wide region in the constellation Virgo after the LAT's first and fifth year of operations. Many additional strong sources (yellow, red) appear in the latest image.
Image Credit: NASA/DOE/Fermi LAT Collaboration
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"More than 1,200 gamma-ray bursts, plus 500 flares from our sun and a few hundred flares from highly magnetized neutron stars in our galaxy have been seen by the GBM," said principal investigator Bill Paciesas, a senior scientist at the Universities Space Research Association's Science and Technology Institute in Huntsville, Ala.
The instrument also has detected nearly 800 gamma-ray flashes from thunderstorms. These fleeting outbursts last only a few thousandths of a second, but their emission ranks among the highest-energy light naturally occurring on Earth.
One of Fermi's most striking results so far was the discovery of giant bubbles extending more than 25,000 light-years above and below the plane of our galaxy. Scientists think these structures may have formed as a result of past outbursts from the black hole -- with a mass of 4 million suns -- residing in the heart of our galaxy.
To build on the mission's success, the team is considering a new observing strategy that would task the LAT to make deeper exposures of the central region of the Milky Way, a realm packed with pulsars and other high-energy sources. This area also is expected to be one of the best places to search for gamma-ray signals from dark matter, an elusive substance that neither emits nor absorbs visible light. According to some theories, dark matter consists of exotic particles that produce a flash of gamma rays when they interact.
entire sky at energies greater than 1 GeV based on five years of Fermi data
This view shows the entire sky at energies greater than 1 GeV based on five years of data from the LAT instrument on NASA's Fermi Gamma-ray Space Telescope. Brighter colors indicate brighter gamma-ray sources.
Image Credit: NASA/DOE/Fermi LAT Collaboration
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"Over the next few years, major new astronomical facilities exploring other wavelengths will complement Fermi and give us our best look yet into the most powerful events in the universe," said Julie McEnery, the mission's project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership. Goddard manages the mission. The telescope was developed in collaboration with the U.S. Department of Energy's Office of Science, with contributions from academic institutions and partners in the United States, France, Germany, Italy, Japan, and Sweden.
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Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Md.
NASA
Guillermo Gonzalo Sánchez Achutegui

miércoles, 13 de junio de 2012

Astronomy: Galaxies NGC 4342, NGC 4291

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., New results based on the two objects shown here are challenging the prevailing ideas as to how supermassive black holes grow in the centers of galaxies. NGC 4342 and NGC 4291, the two galaxies in the study, are nearby in cosmic terms at distances of 75 million and 85 million light years respectively. In these composite images, X-rays from NASA's Chandra X-ray Observatory are colored blue, while infrared data from the 2MASS project are seen in red.
 NGC 4342 and NGC 4291:
Black Hole Growth Found to be Out of Synch
 http://chandra.harvard.edu/photo/2012/ngc4342/

  • Two black holes are challenging the prevailing idea of how giant black holes grow in the cores of galaxies.

  • These black holes are found in the centers of two relatively nearby galaxies: NGC 4342 and NGC 4291.

  • New Chandra data suggest that the growth of these black holes is tied to the envelopes of dark matter around the galaxies, not their bulges.

New results based on the two objects shown here are challenging the prevailing ideas as to how supermassive black holes grow in the centers of galaxies. NGC 4342 and NGC 4291, the two galaxies in the study, are nearby in cosmic terms at distances of 75 million and 85 million light years respectively. In these composite images, X-rays from NASA's Chandra X-ray Observatory are colored blue, while infrared data from the 2MASS project are seen in red.
Astronomers had known from previous observations that these galaxies host black holes with unusually large masses compared to the mass contained in the central bulge of stars. To study the dark matter envelopes contained in each galaxy, Chandra was used to examine their hot gas content, which was found to be widespread in both objects.
By analyzing the distribution of the hot gas, researchers were able to test whether the galaxies had "lost weight" through stars being pulled away during a tidal encounter with another galaxy. Estimates of the pressure of the hot gas, which must balance the gravitational pull of all the matter in the galaxy, showed that massive envelopes of dark matter must exist around each galaxy. Since this tidal stripping would have severely depleted the dark matter, which is more loosely tied to the galaxies than the stars, this process is unlikely to have occurred in either galaxy.
The new results using NGC 4342 and NGC 4291 challenge the long-held idea that black holes at the centers of galaxies always grow in tandem with the bulges of stars that surround them. Rather this study suggests that the two supermassive black holes and their evolution are tied more closely to the amount and distribution of dark matter in each galaxy. In this picture the weights of the black hole and the dark matter envelope in these two galaxies are "normal" and the galaxies are underweight because they formed unusually slowly.
Fast Facts for NGC 4342:
Credit  X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF
Scale  6 arcmin across.
Category  Black Holes
Coordinates (J2000)  RA 12h 23m 39.02s | Dec +07° 03' 14.17"
Constellation  Virgo
Observation Dates  11 Feb 2005 and 17 Feb 2011
Observation Time  31 hours 15 min (1 day 7 hours 15 min)
Obs. IDs  4687, 12955
Color Code  X-ray (Blue); Infrared (Red)
Instrument  ACIS
References Bogdan, A et al. 2012, ApJ (accepted); arXiv:1203.1641
Distance Estimate  About 75 million light years
Release Date  June 11, 2012
Fast Facts for NGC 4291:
Credit  X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF
Scale  8.4 arcmin across.
Category  Black Holes
Coordinates (J2000)  RA 12h 20m 17.70s | Dec +75° 22' 15.47"
Constellation  Draco
Observation Dates  11 Dec 2010
Observation Time  8 hours 22 min
Obs. IDs  11778
Color Code  X-ray (Blue); Infrared (Red)
Instrument  ACIS
References Bogdan, A et al. 2012, ApJ (accepted); arXiv:1203.1641
Distance Estimate  About 85 million light years
Release Date  June 11, 2012


Astronomers had known from previous observations that these galaxies host black holes with unusually large masses compared to the mass contained in the central bulge of stars. To study the dark matter envelopes contained in each galaxy, Chandra was used to examine their hot gas content, which was found to be widespread in both objects.

By analyzing the distribution of the hot gas, researchers were able to test whether the galaxies had "lost weight" through stars being pulled away during a tidal encounter with another galaxy. Estimates of the pressure of the hot gas, which must balance the gravitational pull of all the matter in the galaxy, showed that massive envelopes of dark matter must exist around each galaxy. Since this tidal stripping would have severely depleted the dark matter, which is more loosely tied to the galaxies than the stars, this process is unlikely to have occurred in either galaxy.

The new results using NGC 4342 and NGC 4291 challenge the long-held idea that black holes at the centers of galaxies always grow in tandem with the bulges of stars that surround them. Rather this study suggests that the two supermassive black holes and their evolution are tied more closely to the amount and distribution of dark matter in each galaxy. In this picture the weights of the black hole and the dark matter envelope in these two galaxies are "normal" and the galaxies are underweight because they formed unusually slowly.

Credits: X-ray: NASA/CXC/SAO/A.Bogdan et al; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF

› Read more/access all images
› Chandra's Flickr photoset
 NASA
 Guillermo GOnzalo Sánchez Achutegui
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domingo, 25 de septiembre de 2011

ASTRONOMY: Hubble Captures Image of the Arp 274 Group of Galaxies

Hi My Friends: A VUELO DE UN QUINDE EL BLOG.,On April 1-2, the Hubble Space Telescope photographed the winning target in the Space Telescope Science Institute's "You Decide" competition in celebration of the International Year of Astronomy (IYA).

The winner is a group of galaxies called Arp 274. The striking object received 67,021 votes out of the nearly 140,000 votes cast for the six candidate targets.

Arp 274, also known as NGC 5679, is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy (to the far left) is more compact, but shows evidence of star formation.

Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left.

The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo.

Hubble's Wide Field Planetary Camera 2 was used to image Arp 274. Blue, visible, and infrared filters were combined with a filter that isolates hydrogen emission. The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. A pair of foreground stars inside our own Milky Way are at far right.

The International Year of Astronomy is the celebration of the 400th anniversary of Galileo's first observations with a telescope. People around the world are coming together to participate in the IYA's 100 Hours of Astronomy, April 2 to 5. This global astronomy event is geared toward encouraging as many people as possible to experience the night sky.


A Tale of Three Galaxies
Arp 274, also known as NGC 5679, is a system of three galaxies that appear to be partially overlapping in the image, although they may be at somewhat different distances. The spiral shapes of two of these galaxies appear mostly intact. The third galaxy (to the far left) is more compact, but shows evidence of star formation.

Two of the three galaxies are forming new stars at a high rate. This is evident in the bright blue knots of star formation that are strung along the arms of the galaxy on the right and along the small galaxy on the left.

The largest component is located in the middle of the three. It appears as a spiral galaxy, which may be barred. The entire system resides at about 400 million light-years away from Earth in the constellation Virgo.

Hubble’s Wide Field Planetary Camera 2 was used to image Arp 274 in April 2009. Blue, visible and infrared filters were combined with a filter that isolates hydrogen emission. The colors in this image reflect the intrinsic color of the different stellar populations that make up the galaxies. Yellowish older stars can be seen in the central bulge of each galaxy. A bright central cluster of stars pinpoint each nucleus. Younger blue stars trace the spiral arms, along with pinkish nebulae that are illuminated by new star formation. Interstellar dust is silhouetted against the starry population. A pair of foreground stars inside our own Milky Way are at far right.

Credit: NASA, ESA, and M. Livio and the Hubble Heritage Team (STScI/AURA)
Guillermo Gonzalo Sanchez Achutegui
ayabaca@gmail.com
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