Galaxy Zoo at Galaxy Wars

A research conference on interacting and merging galaxies just concluded today, hosted by East Tennessee State University under the title “Galaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies”. This is a favorite topic of many in the Zoo, and, as you might expect, Galaxy Zoo was represented both in presentations and in the discussion.

Daniel Darg had a poster presentation on the Zoo sample of merging galaxies and their statistical properties. (He also managed to sneak away before I could get his picture next to it). Several speakers on the program compared their results to the Zoo statistics, finding reassuring agreement from various ways of estimating (for example) the fraction of galaxies that we see undergoing mergers. This is a key starting point in working out how important mergers are in the lives of galaxies – how many galaxies result from past mergers? (The better way to phrase that might be “how many mergers have resulted in a typical galaxy”?) Red spirals and blue ellipticals came up in the discussion as well, and more than one speaker tossed in a phrase “Galaxy-Zoo style” for any potential public-participation project. That attests to the Zoo’s impact.

John Wallin (from George Mason University) gave a talk (and an additional poster presentation, seen here) on the developing Zoo offshoot to work out what kinds of galaxy collision produce the distortions and tails (or star streams) that we see in individual galaxy pairs. He demonstrated the beta version of the Java applet to quickly generate an approximate simulation of an encounter and let the user view it at different times or from different angles. The goal here is to narrow down which of a wide possible kinds of collisions (starting from different directions with different spin directions and different galaxy masses) come close enough to the observed structure in galaxies to warrant more detailed (and time-consuming) calculations to match them in detail. Here again, so far people have proven to be much better at this kind of approximate pattern-matching than computers.

I was flattered to have been asked to give an opening historical overvew of the subject. I couldn’t resist ending my talk with a little conferece gift from the Zoo (started by forum regular Pat, with some later cut-and-pasting as I added some galaxies). It even fit with the history format – one astronomer at a meeting first proposing the importance of mergers famously asked whether galaxies could write his name across the sky. Here it is, a card from the Zoo:

A final note that many will find interesting. Linda Smith from the Space Telescope Science Institute took a few minutes of her talk to update us on the commissioning status of Hubble’s new and repaired instruments. Some of the images for the initial public release (September 9) were taken last week. She declined to name the object, but did say that many of the people in this room would be especially interested. I think that also means that many of the people reading this will also be especially interested… They should be unveiled in 49 days – but who’s counting?