This question was posed to me by the citizen scientist, Richard Nowell, who played a major role in the discovery of Green Peas in the Galaxy Zoo. I do not wish to intrude upon any research that might be happening to the GPs, but I am wondering about what the role, if any, is of … More Green Peas and Dark Matter. Q & A with Richard Nowell, Green Pea enthusiast
In previous posts I explained why the Green Peas are really unique in the local universe, and why they are great analogs for galaxies in an early universe. I also explained that Lyman α (or Lyα), a spectral line seen at 1216 Å, contains a lot of information about the gas in galaxies. It is especially … More The Lyman α Emission from Green Peas
The UV spectra of galaxies also contain features in emission. The strongest is the Lyα line, which turns out to be quite tricky. I’ve spent a lot of time on it, so I guess I’m attracted to complicated problems! Let’s go over the basics: Lyman α (Lyα for short) is a recombination line of hydrogen, … More What do we learn from UV spectroscopy of galaxies? (Part 2, Lyman α )
Because galaxies at z>2 have their rest-frame ultraviolet wavelengths shifted into readily observable optical wavelengths, there has been a lot of work in this area for distant galaxies. And it turns out the spectra contain a wealth of information about the gas in galaxies! The UV spectra are not like the SDSS spectra that probe … More What do we learn from UV spectroscopy of galaxies? (Part 1, Gas in Absorption)
When the original Green Pea study was published back in 2009, it was pretty obvious to a lot of people that they might be good analogs for typical galaxies that existed when the Universe was much younger. If true, that turns out to be pretty exciting, because the Green Peas are much, much closer. Therefore, … More It turns out, the Green Peas are really good high-z analogs!
A few years ago, a citizen science project called the Galaxy Zoo found some really neat galaxies. While the group of volunteers were busy classifying the morphological (shape) properties of galaxies in the Sloan Digital Sky Survey (SDSS), they discovered these round, green blobs, that look like this: The Galaxy Zoo named these objects Green … More The Green Peas: An Introduction