Credit: ESA/Hubble & NASA
Acknowledgement: Alessandra Aloisi (STScI) and Nick Rose
The bright streak of glowing gas and stars in this NASA/ESA Hubble
Space Telescope image is known as PGC 51017, or SBSG 1415+437. It is
type of galaxy known as a blue compact dwarf.
This particular dwarf is well studied and has an interesting star formation history. Astronomers initially thought that SBS 1415+437 was a very young galaxy currently undergoing its very first burst of star formation, but more recent studies have suggested that the galaxy is in fact a little older, containing stars over 1.3 billion years old.
Starbursts are an area of ongoing research for astronomers —
short-lived and intense periods of star formation, during which huge
amounts of gas within a galaxy are hungrily used up to form newborn
stars.
They have been seen in gas-rich disc galaxies, and in some
lower-mass dwarfs. However, it is still unclear whether all dwarf
galaxies experience starbursts as part of their evolution. It is
possible that dwarf galaxies undergo a star formation cycle, with bursts
occurring repeatedly over time.
SBS 1415+437 is an interesting target for another reason.
Dwarf galaxies like this are thought to have formed early in the
Universe, producing some of the very first stars before merging together
to create more massive galaxies. Dwarf galaxies which contain very few
of the heavier elements formed from having several generations of stars,
like SBS 1415+437, remain some of the best places to study star-forming
processes similar to those thought to occur in the early Universe.
However, it seems that our nearby patch of the Universe may not contain
any galaxies that are currently undergoing their first burst of star
formation.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Nick Rose.
