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By observing 300 million light-years away in a monstrous galaxy city, astronomers have used NASA's Hubble Space Telescope to perform a complete census of some of its tiniest members: an impressive number of 22,426 globular clusters found to date.
The study, published in the 1945 Astrophysical Journal will allow astronomers to use the field of the globular cluster to map the distribution of matter and dark matter in the cluster of the Coma galaxy, which contains more than 1,000 galaxies packed together.
Since globular clusters are much smaller than whole galaxies – and much more abundant – they trace much better how the tissue of space is deformed by the gravity of the Coma cluster. In fact, Coma's group is one of the first places where the gravitational anomalies observed were considered to reveal an invisible mbad in the universe, later called "dark matter".
Among the earliest homesteaders in the world The globular star clusters are snow globe shaped islands of several hundred thousand ancient stars. They are an integral part of the birth and growth of a galaxy. About 150 globular clusters surround our galaxy of the Milky Way and, as they contain the oldest known stars of the universe, were present in the early years of formation of our galaxy.
Some globular clusters of the Milky Way are visible naked. eye as "stars" blurred. But at a distance from Coma's group, his globules appear as points of light, even for Hubble's clear vision. The investigation revealed globular clusters dispersed in the space between galaxies. They are orphaned from their original galaxy because of near-collisions inside the traffic-jammed cluster. Hubble revealed that some globular clusters align along bridge-shaped patterns. This is the revealing proof of the interactions between galaxies, where they shoot each other gravelly as if to shoot the pull.
Astronomer Juan Madrid of the Australian Telescope National Facility in Sydney, Australia, first thought about the distribution of the globular clusters at Coma when he was examining Hubble. images that show the globular groups extending up to the edge of a given photograph of galaxies in the Coma group.
He was eager to have more data from one of Hubble's old surveys, designed to obtain data from the entire Coma group, called the Coma Cluster Treasury Survey. However, at halfway through the program, in 2006 Hubble's powerful Hubble Camera (ACS) had an electronic failure. (The ACS was later repaired by astronauts during a Hubble interview mission in 2009.)
To fill the gaps in the investigation, Madrid and his team have painstakingly drawn numerous images of the galaxy clusters taken by different Hubble programs. These are stored in the Mikulski Archive for Space Telescopes of the Space Telescope Science Institute in Baltimore, Maryland. He badembled a mosaic of the Central Area of the cluster, in collaboration with students from the National Science Foundation's Undergraduate Research Experience program. "This program offers students enrolled in little or no astronomical universities to gain experience in the field," Madrid said.
The team developed algorithms to screen images of the Coma mosaic containing at least 100,000 potential sources. The program used the color of globular clusters (dominated by the glow of aging red stars) and the spherical shape to eliminate superfluous objects – mainly background galaxies not badociated with the Coma cluster.
Although Hubble has superb detectors with unparalleled sensitivity and resolution, the main disadvantage is that they have tiny fields of view. "One of the interesting aspects of our research is that It presents the amazing science that will be possible with NASA's future wide-field infrared surveyor telescope (WFIRST), which will have a much wider field of view than Hubble, "Madrid said. "We will be able to image clusters of whole galaxies at a time."
The Hubble Space Telescope is an international cooperation project between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, operates the telescope. The Institute of Space Telescope Sciences (STScI) in Baltimore, Maryland, conducts Hubble's scientific activities. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Washington, DC
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