The Faintest Galaxies: What Are They?

We live in a time when searching for and finding the faintest galaxies in the universe is possible. So, where are they?

2767 Views | Published on 6th Mar, 2018

We live in a time when searching for and finding the faintest galaxies in the universe is possible. So, where are they?

The universe contains galaxies at many scales, from diffuse objects to the massive galaxies containing supermassive black holes, often contained in large clusters of galaxies of diverse types. It is interesting to understand how faint galaxies get - do they include even what might be called a mere "collections of stars", larger than star clusters, but not containing organized shapes like spiral galaxies do? How are such illusive objects found? Do computational models predict that such objects exist, and what do they contain? In the nearby universe surveys are used to discover them, but those can only uncover a limited sample of such objects.

Tony Darnell and Carol Christian held this Astronomy Coffee Hangout live on March 8, 2018 at 3PM Eastern Time with Shany Danieli, Pieter van Dokkum and Dr. Marla Geha (Yale University) and discussed the prospects for finding these “integrated light” images of dwarfs, and what telescopes would be optimum for conducting the searches.

Dark matter galaxies (those galaxies there most of the mass is unseen and not in the form or stars or gas) are increasingly being discovered. Astronomers aren't really sure how they form but because of improved observing techniques employed by some of the largest observatories in the world and in space, they are increasingly being seen.

It also isn't very clear when these distant, faint galaxies transition from just a collection of stars into becoming a galaxy. A big question regarding galaxy evolution is when this happens. Right now, having a dark matter halo is considered an important characteristic.

Shaney Daniels has employed an algorithm that helps find these very distant and faint galaxies using data from a variety of datasets, including the Sloan Digital Sky Survey, and the Frontier Fields Campaign by the Hubble Space Telescope.

Even though the hangout is over, we still want to hear from you. Please join the discussion and leave a comment below.

galaxies faint galaxies early universe astronomy live astronomy astro coffee space astronomy first galaxies in the universe

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