Rubin Observatory test images reveal Aquarius IV, an ultra-faint Milky Way satellite galaxy
Astronomers found Aquarius IV, a dwarf galaxy of a few hundred thousand stars about 350,000 light-years away, in test images from the Vera Rubin Observatory.
Astronomers analyzing test images from the Vera Rubin Observatory have discovered the dwarf galaxy Aquarius IV, one of the most compact and faintest satellite galaxies of the Milky Way. The discovery is reported by Kursor, citing Live Science. The system lies about 350,000 light-years from us, and the observatory has not yet officially begun full operation cursorinfo.co.il
Курсорcursorinfo.co.ilOpen source ↗.
What is known about Aquarius IV
It is a classic ultra-faint dwarf galaxy with only a few hundred thousand stars. For comparison, the Milky Way has more than 100 billion. The galaxy lies in the direction of the constellation Aquarius, about 350,000–359,000 light-years from the center of the Milky Way. Our spiral galaxy is about 100,000 light-years across, so Aquarius IV is among the most distant known satellites.
The mass of the system is estimated at 1500 solar masses, roughly a million times less than the mass of the Milky Way. Its absolute magnitude is -1.9, which makes it about 14 million times fainter than our galaxy.
Dark matter and the search for satellites
According to the scientists' calculations, such systems consist of about 99% dark matter, so they emit very little light and escape standard observation methods cursorinfo.co.il
Курсорcursorinfo.co.ilOpen source ↗. Theoretical calculations indicate that hundreds of such satellites should orbit our galaxy, yet only about 60 have been reliably detected. Because of their compactness and faintness, searching for them involves considerable technical difficulties.
The largest known satellites of the Milky Way remain the Large and Small Magellanic Clouds. According to the report, they are gradually approaching our galaxy and will become part of it in the future.
