star formation tagged posts

On a clear evening in April of 1789, the renowned astronomer William Herschel continued his unrelenting survey of the night sky, hunting for new cosmic objects — and found cause to celebrate! He spotted this bright spiral galaxy, named NGC 4707, lurking in the constellation of Canes Venatici or The Hunting Dog. NGC 4707 lies roughly 22 million light-years from Earth. Credit: ESA/Hubble & NASA

On a clear evening in April of 1789, the renowned astronomer William Herschel continued his unrelenting survey of the night sky, hunting for new cosmic objects – and found cause to celebrate! He spotted this bright spiral galaxy, named NGC 4707, lurking in the constellation of Canes Venatici or The Hunting Dog. NGC 4707 lies roughly 22 million light-years from Earth.

NGC stands for “New General Catalo...

A new model explains the exceptions to the galaxy main model sequence

The more massive, or full of stars, a galaxy is, the faster the stars in it are formed. This seems to be the general rule, which is contradicted, however, by some abnormal cases, for example thin (not massive) galaxies that are hyperactive in their star formation. Until now the phenomenon had been explained by catastrophic external events like galaxies colliding and merging, but a new theory offers an alternative explanation, related to an in situ (internal) process of galaxy evolution. The new theory correctly reproduces the behaviour of both normal and abnormal (or outlier) galaxies, and may be further tested by new observations.

If we put the galaxies for which we have the relevant data into a graph relating the mass ...

A deep photographic image of M83 taken using the UK Schmidt Telescope by Malin & Hadley (1997, figure reproduced with permission) where the white scale bar corresponds to 30 arcmin. The northern stream appears not to be associated with dw1335-29, circled in red. Credit: Carrillo et al., 2016.

M83, Southern Pinwheel Galaxy has a newly found dwarf satellite 85,000 light years from its host. This satellite galaxy was designated dw1335-29 and could be an irregular or a transition dwarf. Messier 83 is one of the closest and brightest barred spiral galaxies. It is located about 15 million light years away in the constellation Hydra. Finding new satellites of galaxies beyond the Local Group such as Messier 83 could provide essential insights on galaxy formation in a cosmological context.

In 2015,...