|CANDELS astronomers listening to talks. Image credit: Janine Pforr|
With the plenary sessions of Tuesday and Wednesday behind us, Thursday was a busy day of working group splinter sessions. Several of the different working groups got together in smaller numbers to discuss specific topics. This morning started off with the Structure and Morphology Working Group Session that I organized. To kick off the session I gave an overview talk about the status of the group, the papers we have been working on, and the catalogs we have produced. After this, we had a fun series of quick talks (ten minutes total for each, including discussion!). The purpose of these talks was to give the entire group a flavor of what everyone else is working on and the status of various projects. They also allowed us a chance to ask questions and discuss some interesting scientific topics. There were 17 of these talks in total, spanning a wide range of topics.
Our group will meet again this morning, this time to discuss future research topics. In particular, we want to decide upon the most important scientific questions that we should be answering in the next year with our rich set of data. The science that can be done is unlimited, so a discussion like this really helps us to focus on what would be the most interesting and the most useful to the scientific community.
During the afternoon, there were three concurrent sessions. It was tough to decide which one to go to! I chose to go to the session on Education and Public Outreach, lead by Janine Pforr. During this session, we mapped out strategies for how to proceed with this blog in the future. We brainstormed about possible post topics that would be interesting to our readers as well as ways to increase our readership. We also discussed some other project ideas and started to get organized about what information is needed and who could be appointed to coordinate. We think we came up with a lot of great ideas and you'll be hearing more about them in the future!
While we were discussing EPO, the star formation rate indicators group was also meeting. Unfortunately, I had to miss it but I got to hear a lot about it from my collaborators and it seems that they had some very interesting discussions on how to best measure the rates at which galaxies form stars. The stars that influence star formation rates the most are massive stars. Massive stars are very bright in ultraviolet light. You might guess that if we could measure the total ultraviolet light from a galaxy, then we would be able to measure the total star formation rate. This is only half true. It turns out that galaxies are not that simple. A lot of them also have dust, and that dust hides the ultraviolet light from galaxies -- just like a hazy day when light from the Sun is blocked. So if we only use ultraviolet light, we will underestimate the star formation rate. Fortunately, the hidden ultraviolet light isn't lost. It goes toward heating the dust and then that dust emits light in the infrared. Because of this, astronomers try to gather both ultraviolet and infrared light from galaxies to recover the true star formation rate of galaxies. This method is just an example. There are many other ways that have been proposed to measure star formation rates. Yesterday's discussion certainly helped us to get one step closer to obtaining the real number of newly born stars in distant galaxies. New data sets in the CANDELS fields, including far-infrared imaging from the Herschel Space Observatory and near-infrared spectroscopy from the WFC3 grism, will be immensely useful for addressing this question.
The third group that met was the theory working group. The group discussed some of their own data products, including catalogs based on simulations. These simulations are very useful for observers, so one of the main goals of this session was to discuss the best way to combine theoretical models with observations from CANDELS.
Today, the last day of our meeting, several other groups will be meeting (AGN, UV, high redshift galaxies) to have similar discussions about their science results so far and their plans for the future. It's hard to believe that the meeting is almost over!