Pea Galaxies

Date of the discovery: 15 October 2009

Short Description: Pea Galaxies or also known as Grean Peas (GPs) were discovered by multiple volunteers in a discussion started by Hanny Van Arkel called “Give peas a chance”. They have a green appearance and are unresolved in the Sloan Digital Sky Survey. The green colour comes from doubly ionized oxygen [OIII], showing a high star-forming rate of about 10 solar masses per year. They were a new type of small compact galaxy that does not appear in the present-day universe. They are similar to the galaxies in the early universe that caused our universe to re-ionize (e.g. Lyman-break galaxies and Lyα emitters). This makes them a ideal sample to study this phenomenon.

Volunteer(s): “Pea Corps” Elisabeth Baeten, Gemma Coughlin, Dan Goldstein, Brian Legg, Mark McCallum, Christian Manteuffel, Richard Nowell, Richard Proctor, Alice Sheppard, Hanny van Arkel

Researchers in the discovery paper: Carolin Cardamone, Kevin Schawinski, Marc Sarzi, Steven P. Bamford, Nicola Bennert, C. M. Urry, Chris Lintott, William C. Keel, John Parejko, Robert C. Nichol, Daniel Thomas, Dan Andreescu, Phil Murray, M. Jordan Raddick, Anže Slosar, Alex Szalay, Jan Vandenberg

Link to paper in ADS:

SIMBAD page:

Telescopes involved: Apache Point Observatory (SDSS 2.5m telescope), Hubble Space Telescope, GALEX

Figure 1 of the paper showing a gri composite colour image of SDSS data. Three grean peas and one elliptical galaxy to the right to compare with the grean peas
Other pages:


Press Release:

Project website: galaxy zoo

Credit for the header image: Cardamone et al. 2009; HST ACS & WFPC2

Go back to the timeline↵