Astronomy Science ~ Using data from the Dark Energy Survey (DES), astronomers have discovered nine new ultra-faint satellite galaxies of ou...
Astronomy Science ~ Using data from the Dark Energy Survey (DES), astronomers have discovered nine new ultra-faint satellite galaxies of our Milky Way. Based on morphological characteristics, three new satellites are dwarf galaxies, one of which is located at the very edge of the Milky Way. The remaining six are objects that have the size and luminosity comparable to a very dim dwarf galaxy, called Segue 1, and it can be a dwarf galaxies or globular clusters.
"The discovery of so many small satellite galaxies in the sky totally unexpected. I could not believe my eyes," said Dr. Sergey Koposov of the Institute of Astronomy at Cambridge University, UK, who is the first author of the report submitted and published in the Astrophysical Journal .
The new satellite is found in the southern hemisphere near the Small and Large Magellanic Cloud, a dwarf galaxy the largest and most famous in orbit the Milky Way.
These objects are named Reticulum 2, Eridanus 2, Horologium 1, Pictoris 1, Phoenix 2, Indus 1, Grus 1, Eridanus 3, and Tucana 2 - one billion times fainter than the Milky Way and its mass is less massive one million times more.
Closest satellite galaxies are Reticulum 2, is about 97,000 light-years away, while the most distant, Eridanus 2, is more than a million light years. Eridanus 2 is a dwarf galaxy that is located on the edge of the halo of the Milky Way, which is about 1.24 million light-years away. This dwarf galaxies show signs of the formation of new stars and may even have a faint globular clusters.
With its location on the outskirts of our galaxy, high luminosity and a diameter of about 1,120 light-years away, Eridanus 2 seems to be the twin of the dwarf galaxy Leo T. This object is clearly visible in the color image DES as a faint blue star clusters are embedded in the blue cloud that has a low brightness.
Tucana 2 is located at a distance of about 225,000 light-years away from us. It can be classified as ultra-faint dwarf galaxies as luminosity and diameter of about 1,300 light-years away. With a size of about 455 light-years away, dwarf galaxies Grus 1 is the third largest object in the sample. This object is about 390,000 light years.
Reticulum 2 is a very long object in the constellation Reticulum. Length of about 200 light-years, with the axis ratio of about 0.6. Because the tidal forces of our galaxy, galaxies Reticulum 2 in the process of being torn apart.
Meanwhile, ultra-faint galaxies Horologium 1 has a diameter of about 195 light years and lies at a distance of 325,000 light years. Eridanus 3, ultra-faint objects is 290,000 light-years away and has the smallest size in the sample, only 117 light-years away.
Phoenix 2 is located at a distance of about 270,000 light-years away and has a diameter of about 175 light-years away. Pictoris 1 is about 370,000 light-years away and has a diameter of about 200 light-years. Similar to most of the samples, the Indus 1 located at a distance of 325,000 light-years away and has a diameter of about 250 light-years away.
"These results are very confusing," said co-author Dr. Wyn Evans, also of the University of Cambridge Institute of Astronomy. "Maybe they are the Magellanic Clouds orbiting satellites and wasted by the interaction of Large and Small Magellanic Clouds.
He added: "Maybe they've become part of a giant galaxy clusters together with the Magellanic Clouds and fall into our Milky Way galaxy." Dr. Vasily Belokurov of Cambridge University's Institute of Astronomy, co-author of the study, said: "dwarf satellite is the deadline to test our theory of dark matter."
"The discovery of so many small satellite galaxies in the sky totally unexpected. I could not believe my eyes," said Dr. Sergey Koposov of the Institute of Astronomy at Cambridge University, UK, who is the first author of the report submitted and published in the Astrophysical Journal .
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| An infrared map of our Milky Way galaxy, showing 9 new objects - dwarf galaxies and / or globular clusters - marked in red. |
These objects are named Reticulum 2, Eridanus 2, Horologium 1, Pictoris 1, Phoenix 2, Indus 1, Grus 1, Eridanus 3, and Tucana 2 - one billion times fainter than the Milky Way and its mass is less massive one million times more.
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| Eridanus 1, one of the three most recent satellite galaxies orbiting our Milky Way. |
Closest satellite galaxies are Reticulum 2, is about 97,000 light-years away, while the most distant, Eridanus 2, is more than a million light years. Eridanus 2 is a dwarf galaxy that is located on the edge of the halo of the Milky Way, which is about 1.24 million light-years away. This dwarf galaxies show signs of the formation of new stars and may even have a faint globular clusters.
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| The new satellite galaxy Horologium-1. |
With its location on the outskirts of our galaxy, high luminosity and a diameter of about 1,120 light-years away, Eridanus 2 seems to be the twin of the dwarf galaxy Leo T. This object is clearly visible in the color image DES as a faint blue star clusters are embedded in the blue cloud that has a low brightness.
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| The new satellite galaxy of the Milky Way Pictoris 1. |
Tucana 2 is located at a distance of about 225,000 light-years away from us. It can be classified as ultra-faint dwarf galaxies as luminosity and diameter of about 1,300 light-years away. With a size of about 455 light-years away, dwarf galaxies Grus 1 is the third largest object in the sample. This object is about 390,000 light years.
Reticulum 2 is a very long object in the constellation Reticulum. Length of about 200 light-years, with the axis ratio of about 0.6. Because the tidal forces of our galaxy, galaxies Reticulum 2 in the process of being torn apart.
Meanwhile, ultra-faint galaxies Horologium 1 has a diameter of about 195 light years and lies at a distance of 325,000 light years. Eridanus 3, ultra-faint objects is 290,000 light-years away and has the smallest size in the sample, only 117 light-years away.
Phoenix 2 is located at a distance of about 270,000 light-years away and has a diameter of about 175 light-years away. Pictoris 1 is about 370,000 light-years away and has a diameter of about 200 light-years. Similar to most of the samples, the Indus 1 located at a distance of 325,000 light-years away and has a diameter of about 250 light-years away.
"These results are very confusing," said co-author Dr. Wyn Evans, also of the University of Cambridge Institute of Astronomy. "Maybe they are the Magellanic Clouds orbiting satellites and wasted by the interaction of Large and Small Magellanic Clouds.
He added: "Maybe they've become part of a giant galaxy clusters together with the Magellanic Clouds and fall into our Milky Way galaxy." Dr. Vasily Belokurov of Cambridge University's Institute of Astronomy, co-author of the study, said: "dwarf satellite is the deadline to test our theory of dark matter."
