1. Main
  2. Learn
  3. Industry
  4. Science, Technologies

New dwarf galaxy discovered around Milky Way

© Shutterstock © Shutterstock

Astronomers have identified a new ultra-faint dwarf satellite companion of our Milky Way Galaxy, sci-news.com reports.

Roughly 50 known galaxies orbit the Milky Way. About 40 of them are faint and diffuse, and belong to the category of dwarf spheroidal galaxies.

Many of the recently discovered dwarf galaxies, especially those seen in large surveys such as the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey (DES), are extremely faint. These are so-called ‘ultra-faint dwarf galaxies.’

The faintest dwarf satellites identified so far are Segue 1, discovered by the SDSS, and Cetus II, detected as part of the DES survey. The latter is yet to be confirmed, as it’s too compact to be a galaxy.

Left: the position of Virgo I in the constellation of Virgo. Right: a density map of Virgo I’s member stars in a 0.1 deg x 0.1 deg area. Image credit: Tohoku University / NAOJ.

It lies at a distance of 284,000 light-years away from us in the constellation of Virgo, and is beyond the reach of SDSS, which has previously surveyed the same area.

“We have identified a new ultra-faint dwarf satellite of the Milky Way, Virgo I, in the constellation of Virgo,” the astronomers said.

“The satellite is located at a heliocentric distance of 284,000 light-years and its absolute magnitude in the V band is estimated as -0.8 mag, which is comparable to or fainter than that of the faintest dwarf satellite, Segue 1.”

“The half-light radius of Virgo I is estimated to be 124 light-years, significantly larger than globular clusters with the same luminosity, suggesting that it is a dwarf galaxy.”

he discovery was made as part of the ongoing Hyper Suprime-Cam Subaru Strategic Program.

“We have carefully examined the early data of the Subaru Strategic Survey with Hyper Suprime Cam (a gigantic wide-field camera on NAOJ’s Subaru Telescope on Mauna Kea, Hawaii) and found an apparent over-density of stars in Virgo with very high statistical significance, showing a characteristic pattern of an ancient stellar system in the color-magnitude diagram,” said team member Daisuke Homma, a graduate student at Tohoku University in Japan.

“This discovery implies hundreds of faint dwarf satellites waiting to be discovered in the halo of the Milky Way,” said team member Dr. Masashi Chiba, also from Tohoku University.

“How many satellites are indeed there and what properties they have, will give us an important clue of understanding how the Milky Way formed and how dark matter contributed to it.”

sci-news.com

Nobel prizewinner proposes a new city in KZ
New abnormal snowfalls expected in Kazakhstan
Huge glacier retreat triggered in 1940s
Hyperloop construction begins in Las Vegas
"Moonlight" to top Spirit Awards nominations
Oil prices fall due to investors uncertainty
New dwarf galaxy discovered around Milky Way
Kanat Islam becomes a top ten WBO boxer
World oil prices continue to rise
Kazakhstan expects warming - Kazhydromet
Merkel to seek fourth term as chancellor
Sale of Tintin drawings set to break records
US, EU stocks fall as markets focus on dollar
Pacific leaders urged to defend free trade
EU warns eight nations on budget deficit
Universiade-2017: Athletic Village is ready
Bob Dylan can't make Nobel ceremony
Messi will never leave Barca - club president
Google, Facebook take aim at 'fake' news
Aerosmith announces Europe 'farewell' tour
Putin, Trump to normalise US-Russia ties
At least 10 hurt in southern Turkey blast
6.2 quake hits western Japan
OPEC agrees shock oil output cut
Israeli ex-president and Nobel laureate Peres dies
Germany blocks WhatsApp data transfers to Facebook
32,000 arrested in Turkey coup probe
Youth to the fore as Milan fashion week opens
Xenophobia threatening peace in eastern Germany
Four-in-10 Japanese are virgins: poll
Sweden re-militarises Baltic island of Gotland
China to launch second space laboratory: Xinhua
More than a billion stars mapped in Milky Way: ESA
Boxing: Golovkin eyes Saunders after stopping Brook
Kazakhstan shifts PM to security chief
Oil prices gain despite rising OPEC supply forecast
US to give Philippines military planes
Singapore wages war on Zika-bearing mosquitoes
Italy quake death toll nears 250
Viral photos add fuel to French burkini debate
18 dead as Italy struck by powerful quake
Japan's first lady visits Pearl Harbor
Pokemon's a no-go on Bangkok's roads
July was Earth's hottest month in modern times
Pakistan rock climbers scale new heights