These are a few additional details of their study and why they think this is a reasonable hypothesis:

“A globular cluster might be the first place in which intelligent life is identified in our galaxy,” lead study author Rosanne Di Stefano, of the Harvard-Smithsonian Center for Astrophysics, said in a statement. Di Stefano presented the new research today (Jan. 6) here at the 227th meeting of the American Astronomical Society.  Globular clusters are massive groupings of millions of stars in a region only 100 light-years across. The clusters date back to the early life of the Milky Way — nearly 10 billion years ago. (For comparison, the universe is approximately 13.7 billion years old.) Although these clusters’ age raises some questions, it also provides ample time for civilizations that emerged to evolve and become complex.

This potentially deserves further discussion.

And this video examines a very peculiar cluster:

Immense star clusters in the nearby Fornax Dwarf spheroidal galaxy should have formed much in the same way as our Milky Way. But older stars – which are present in ‘our’ globular clusters – are not visible in the Fornax.

thanks to space.com for the great info

thanks to NASA for the pic