Unveil the mystery of gamma ray

NASA reports that the bursts come from the destruction of a star that is too close to a massive black hole

 

Among scientists study is the director of the Institute of Astronomy, UNAM, William Lee (Foto: Especial )

 

Thursday June 16, 2011 Notimex | El Universal22:00

Less than two months, on 28 March, NASA's Swift satellite pinpointed a burst of gamma rays coming from the destruction of a star that got too close to a massive black hole in the center of a distant galaxy, he to meet an international group of astronomers.
The scientists, among which is the director of the Institute of Astronomy, UNAM, William Lee, released by the journal Science, indicated that the Swift satellite has spent nearly seven years of observing the sky hunting, among other things, flashes of gamma rays.

These flashes represent the light of higher energy there to try to unravel the mystery of its origin.
Although uncertainties remain, experts believe that most of the rays are generated when high mass stars collapse at the end of his life and form a black hole.
This is followed by the emission of radiation as a narrow jet that lasts only minutes, but due to its high intensity can be detected even occur in very distant galaxies.
These flares can release very soon so much energy as the Sun has issued since it was formed, made ​​five billion years.

Interestingly, the burst that Swift satellite detected (called SW 1644 +57), although it seemed routine lasted longer than usual.
Located in the center of a galaxy in the constellation Draco, at almost four billion light years from Earth, shone unusually SW 1644 +57 in the satellite monitors for days, a record for this type of phenomena.

After the flare detected, astronomers-institutional U.S., Europe and Mexico decided to track and studied with the Hubble Space Telescope and the Chandra X-ray telescope, both orbited and operated by NASA.
They also sought information on how it looked before exploding the galaxy. Everything indicates that like many others, has at its heart a very massive black hole, in this case a level equivalent to a million suns, medium compared with larger, which can weigh up to one billion stars.
Most times they are calm and remain invisible, but if a star passes by, can be destroyed by the violent pull of the black hole and be swallowed by it, UNAM said in a statement.
All studies conducted by astronomers suggest that this seems to have been the case with SW 1644 +57. Probably a star the size of our sun would have reached a dangerous area near the black hole and it would have disturbed strongly undoing; swallowed much of his material.

Black holes common in early universe

Astronomers note that the holes grew more aggressively, the pair of galaxies that host them

 

FORMATION OF THE UNIVERSE. According to this new study very young black holes grew more aggressively, the pair of galaxies that host them (Foto: NASA / Chandra )

Wednesday June 15, 2011 Notimex | El Universal22:00

A team of astronomers from the University of Michigan (UM) found the first direct evidence that giant black holes were common in the early universe.
The experts turned to Chandra X-ray of the National Aeronautics and Space Administration (NASA), which detects very faint objects at great distances, and led the team to a selected portion of the sky for six weeks.
According to research published this week in the journal Nature, very young black holes grew more aggressively, the pair of galaxies that host them.
By combining optical and infrared images obtained by the Hubble Space Telescope from NASA, the new Chandra data enabled the astronomers find black holes in 200 distant galaxies when the universe was between 800 million and 900 million years old.
"We had reason to expect that black holes exist in many of the earliest galaxies which until now had eluded our searches," said Marta Volonteri, UM astronomer and co-author of the study.
"By comparing the Chandra data with theoretical models, the match was amazing," said the astronomer.

Because black holes are almost all wrapped in thick clouds of gas and dust, often do not detect optical telescopes, but x-rays allows the study.
The large growth means that black holes are related to quasars, bright objects and rare materials strengthened with falling into supermassive black holes giants.
The investigation determined that between 30 and 100% of distant galaxies contain supermassive black holes grow giant.

Volonteri explained that 'the extrapolation of these results from the small field of sky observed the entire sky' to estimate that there are at least 30 million super-giant black holes in the universe.
"This is a factor 10 000 times the estimated number of quasars in the early universe," he said.
"We seem to have found a whole new children's population of black holes," noted study co-author Kevin Schawinski of Yale University.
Scientists had expected to have a population of black holes babies in the early universe, but so far not been observed.
Detailed calculations show that the total growth of black holes observed by the team is about a hundred times greater than most recent estimates.
"Until now we had no idea what made ​​black holes in these early galaxies, or even exist. Now we know they are there and are growing momentum," said Ezequiel Treister of the University of Hawaii and author of the study.
While there is evidence of parallel growth of black holes and galaxies at closer distances, the new Chandra results show that the connection starts earlier than previously thought, perhaps since the origin of both.
"It is thought that in the present universe, black holes and galaxies grow in a symbiotic manner, and we have shown that this co-dependent relationship has existed since the early days," said Priya Natarajan, coauthor of Yale University.

Found second black hole in center of galaxy

 Scientists have detected a black hole in Markarian first 739 or NGC 3758 is located 425 million light years from Earth in the constellation Leo

 

For decades scientists have known of the black hole located east of the galaxy, is the second system with two holes found (Foto: Especial NASA SDSS )

June 10, 2011 Renata Sánchez | El Universal22:20
Other supermassive black hole was found in the center of a galaxy close to Earth that was already identified another hole, scientists reported in an article in The Astrophysical Journal Letters.
The galaxy known as NGC 3758 Markarian 739 or is located 425 million light years from Earth in the constellation Leo. The astronomers found that the two nuclei of the galaxy are separated by 11 thousand light years and each contains a black hole that consumes the gas falling into it.

Friday

The scientists used data from the Swift satellite and Chandra X-ray Observatory to find the second supermassive black hole, according to the U.S. space agency (NASA) on its website.
Markarian 739 was observed with visible light but was not detected anything until Chandra and Swift provided data that showed another nucleus.

"In the vast majority of the hearts of galaxies, including our own Milky Way, are supermassive black holes weighing millions of times the mass of their soles. Some of them also radiate billion times the energy of their stars, "said Michael Koss, leader of the team that published the article and a researcher at Goddard Space Flight Center of NASA and researcher at the University of Maryland at College Park.
The centers of the galaxies that are so intense emissions are known as active galactic nuclei (AGN), these are the areas that are generally black holes, but only 1% are considered so powerful AGN.
The binary system of AGN has Markarian 739 is the second to the scientists found. Many scientists believe that major disasters such as galaxy collisions can form the AGN, the disclosure of information which would help clarify to understand the origin of the universe.
Since 2004, the telescope Swift BAT ship has been creating a map of the sources of high energy X-rays across the sky. This probe is sensitive to AGN that are more than 650 million light years away from Earth.