More about CANDELS at the AAS

As mentioned by Liz McGrath in her recent blog post, the American Astronomical Society held its 223rd meeting  in early January. Altogether there were 37 presentations that had the word CANDELS somewhere in their title, author list, or abstract, and probably several others that used CANDELS under the radar. I thought it worth sharing a few highlights.

The meeting opened with the Kavli lecture by Bob Williams, the former director of the Space Telescope Science institute and president of the International Astronomical Union, who recounted the history of the original Hubble Deep Field and the science legacy that flowed from that first observation. One of the things he emphasized is how the making the data completely non-proprietary helped build the scientific momentum. Instead of observing separate spots in the sky and keeping the data to themselves, astronomers interested in the distant universe were suddenly much more willing to point telescopes to the same spot and share the data. CANDELS carries forward the legacy of this culture change; all of the Hubble data and most of the data from other telescopes are available to everyone.

A figure from Steve Finkelstein's talk, showing the number of galaxies found at redshifts
z=7 and 8 from the ultra-deep survey fields (blue) and CANDELS (red). Absolute magnitude
is a measure of brightness, with smaller numbers (more negative) indicating brighter galaxies.
CANDELS is great for finding brighter (rarer) galaxies, while the ultra-deep fields
excel at finding fainter (but more common) galaxies.

On Monday afternoon, the CANDELS and CLASH projects were featured in a special session. This was an opportunity for astronomers from both projects to give a top-level summary of the results. The CANDELS talks were given by Jeyhan Kartaltepe, Steve Finkelstein, Yu Lu and Steve Rodney. Jeyhan summarized the results on galaxy morphology, with particular attention to the CANDELS visual classifications and the evidence that ultraluminous infrared galaxies are associated with galaxy collisions and mergers, even at high redshift. Steve Finkelstein summarized the state of research on the most distant galaxies. He showed a nice diagram that helps to put into perspective the contributions of the "deep but narrow" fields (the Hubble Ultradeep field and associated parallel observations), and CANDELS. He also talked his discovery of what is currently the record-holder for the most distant spectroscopically confirmed galaxy, at redshift z=7.51. Yu Lu summarized the effort of part of the CANDELS theory group to compare semi-analytical models of galaxy formation. This is the most detailed side-by-side test of such models yet carried out and will be of great utility in helping us understand what we are learning from CANDELS. Finally, Steve Rodney partnered with Or Graur of the CLASH team to give a summary of the supernova program, including the first estimates of the evolution of supernova rates from both surveys.

A figure from Guillermo Barro's talk about the evolution of compact galaxies at high redshift.
The vertical axis shows how active the galaxy is in forming stars. Specifically, it shows
the ratio of each galaxy's star-formation rate, to its total stellar mass. The horizontal axis
shows how densely packed the stars are together. Dense galaxies are to the right,
diffuse galaxies are to the left. Guillermo is finding that galaxies tend to make the
transformation from being diffuse to being compact while they are still forming stars;
the quenching of star formation happens later.

The next day, CANDELS figured prominently in the Hieneman prize lecture given by Rachel Somerville. Rachel has been one of the leaders of the theory effort in CANDELS and recounted the progress in trying use the observations to get at the detailed physics of galaxy formation. One of the more recent results she showed in her talk was the success that she and Lauren Porter have had in matching the trends that Guillermo Barro and Christina Williams see in the evolution of compact galaxies. Both Guillermo and Christina spoke that morning in a session about galaxy surveys that was almost entirely populated by CANDELS talks.

In addition to the talks, there were quite a few posters. Posters are tacked to display boards in a big exhibition hall, and stay up all day. On the plus side, this gives people an opportunity to wander by and discuss the research, which is harder to do in a session packed with 5-minute talks. On the minus side, there are so many posters that it impossible to look at them all. CANDELS was very fortunate to have most of our posters on the first day located right near the entrance to the hall, so there was lots of opportunity for people to see them.

It was also great to see work by other groups using the CANDELS data. One of the press releases from the meeting was from Garth Illingworth, discussing finding some suprisingly bright galaxies in the CANDELS GOODS-N data that might be at redshift z>9. These are not yet spectroscopically confirmed, but if they are really at high redshift, then they indicate that star-formation was already proceeding vigorously when the universe was only 500 million years old.

223rd AAS Meeting in Washington, D. C.

Twice a year, the American Astronomical Society holds professional meetings covering a broad range of research and education topics. This January’s meeting was held in Washington, D. C. at the National Harbor. I wouldn’t be surprised if it broke previous attendance records, with almost 3200 people on the official registration list. 

Rachel Somerville giving the Heineman Prize Lecture.
Photo credit: Joson Images/ AAS

CANDELS scientists had a very strong representation at this meeting. Rachel Somerville won the Heineman Prize and gave a lecture entitled, “The Formation of Galaxies and Supermassive Black Holes: Insights and Puzzles.” Meanwhile, Jennifer Lotz held a press conference on the release of data from a new ultra-deep, wide-field imaging survey that she is leading known as the Hubble Space Telescope Frontier Fields (see the image from their press-release below).  There was also a CANDELS special session which included 4 talks and 10 posters on CANDELS results, as well as 22 other CANDELS-related talks and poster presentations throughout the course of the meeting.

HST Frontier Field Abell 2744.  Image credit: NASA,
ESA, and J. Lotz, M. Mountain, A. Koekemoer, and
the HFF Team (STScI).

People go to the AAS for a variety of reasons. As one of the largest gatherings of astronomers, it is impossible to see every science talk of interest. For this reason, I find AAS meetings are more of a place to have discussions with your colleagues and the larger astronomical community about priorities and goals for the future. Many of these larger, community-oriented discussions take place during “town hall” sessions.  Sometimes difficult decisions need to be made, especially in the current funding climate. At this meeting, astronomers grappled with the likelihood that many of our beloved facilities will either need to find private partners to sustain operations costs, or be shut down in the next couple years. This is because NSF does not have the money to fund them while continuing forward with important projects like the James Webb Space Telescope and the Large Synoptic Survey Telescope. If you know anyone with a few hundred thousand dollars to spare, you can buy yourself some quality time on top-notch facilities!

Other important discussions include networking with more senior astronomers, especially when you’re on the job hunt. Jon Trump wrote about this aspect of AAS in a previous post.  However, the largest growing demographic at these meetings is young student researchers. This is a great place for them to showcase their work and gain experience talking with people about their research. For me, this was my first AAS meeting where I was on the “other side”, serving as faculty advisor to an undergraduate student who is applying to graduate school this year. As my first thesis student, I encouraged her to come present her results, while I tried my best to introduce her to people doing exciting science as well as folks on various graduate admissions committees. The AAS can be a bit daunting to newcomers, so it’s the advisor’s role to help facilitate discussion and provide a role model for students just starting down this career path.

Neil deGrasse Tyson at the AAS.
Photo credit: Joson Images/ AAS

In addition to science talks, there were a number of sessions on astronomy education research, which is another growing aspect of the AAS community. One session I attended on how to improve student outcomes in Astro 101-style courses, was standing room only. It’s great to see so many professional astronomers care so deeply not just about their personal research, but also about how to improve their approach to teaching science to non-science majors. While this is a significant part of many of our jobs, it may surprise readers to learn that most of us were never trained as teachers. Therefore, these sessions are particularly important for learning how to be effective instructors.

Astronomers also like to have a bit of fun in these meetings. At this meeting there was a special talk by Neil deGrasse Tyson, who was surrounded by hundreds of adoring, geeky fans (a.k.a, professional astronomers) as he talked about how to use twitter to engage the public in science. There was also the infamous AAS “after-party”, which was a bar-hopping extravaganza, complete with astro-themed cocktails and a mechanical bull (although I never did see anyone attempt the bull)!

Space Shuttle Discovery at the National Air and Space
Museum.  Photo credit: E. McGrath

Finally, with the meeting being held in Washington D. C., I took advantage of the opportunity to do some astronomy-themed sightseeing. I visited the National Air and Space Museum hangars located near Dulles airport, where I got to behold the impressive Space Shuttle Discovery, as well as a Mars Pathfinder prototype. The shuttle was even more impressive in person than I could have imagined—definitely worth a visit next time you're in D. C.

The Universe Explored by Herschel

The Herschel Space Observatory
Image credit: ESA (Image by AOES Medialab);
Background: HST, NASA/ ESA/ STScI

After nearly four years of operation, on April 29, 2013 the Herschel Space Observatory finished its mission. However, this was not the end of its job. The wealth of data from Herschel is still being analyzed and new results are being discovered. A conference, "The Universe Explored by Herschel," was held in the Netherlands from Oct 15-18 to discuss exciting results that have been made with Herschel.

Herschel is a space telescope that was launched on May 14, 2009. Its mirror is 3.5m which makes it the largest space telescope launched so far. It observed the sky in the infrared. Why do astronomers care about infrared? Infrared allows astronomers to detect dust emission that is caused by objects embedded in the dust, observe low temperature objects like some planets, and study high redshift galaxies. Herschel could observe the wavelength range of 60-670 microns in the infrared. This range covers a part of the infrared bump of dust emission in galaxies and many important infrared spectral lines that play a role in determining gas properties in the interstellar medium. CANDELS also has 85-670 micron deep imaging data taken with Herschel in the GOODS-S, GOODS-N, COSMOS, and UDS fields. With these data sets, we can detect the dust emission in distant galaxies.

During the conference, I mainly attended the sessions related to galaxy formation and evolution. Infrared galaxies were common in the early universe and they dominated the star formation history. We discussed how infrared galaxies were formed and evolved -- how much dust these galaxies have, what is the dust temperature, how many stars they made at a given period (star formation rates), why some of them have intense star formation compared with typical star-forming galaxies, how they stop making stars, what kind of shapes they have, what mechanisms heat the dust, etc. 

View of a canal in Leiden. Image Credit: H. Inami

From the CANDELS team, Jeyhan Kartaltepe displayed a poster (shown below) presenting interesting results on the morphology of galaxies detected with Herschel. In particular, she explored the role that galaxy mergers play in high redshift ultraluminous infrared galaxies. David Rosario discussed the connection between active galactic nuclei and star formation using the Herschel data. I presented infrared luminosity functions built with our own Herschel data, and star formation rate comparisons based on the infrared luminosity and the optical/near-infrared spectral energy distribution fitting, which Janine Pforr has been working on. Without Herschel, it would have been difficult to answer these questions accurately. Although Herschel is not observing anymore and many interesting discoveries have been made, astronomers are still working hard to explore the infrared universe using its data.

Image Credit: J. Kartaltepe

Drinking Bourbon, Talking Astronomy: the CANDELS Lexington Meeting

CANDELS team.  Photo courtesy: D. Kocevski

This year was my first ever CANDELS team meeting, and I didn't know quite what to expect. I knew there would plenty of discussion about galaxies, but after that I was unsure.  

I was nervous to give a talk to my largest audience yet. I was giving a presentation on my research about the structure and shape of galaxies with an active galactic nucleus (for more information on "AGN" check out this post) when these galaxies live either really close to other galaxies or far away from other galaxies. I eventually settled into a nice fluid delivery pretty quickly and realized quickly that 20 minutes really isn't that long.

Astronomers busy listening and working.
Photo courtesy: D. Kocevski

In addition to my talk there were many, many others. On subjects ranging from supernovae to large scale computer simulations of the formation and evolution of galaxies. Some of the most interesting presentations dealt with something called "candelizing" images. This process takes simulated galaxies and blurs them to a point where they resemble real galaxies that would be observed in CANDELS images (hence candelizing). When a galaxy simulation is performed, theoretically all knowledge about it is known.  

These "candelized" images can help with the visual classifications of galaxies, both by professional astronomers (in CANDELS) and amateur astronomers (through Galaxy Zoo). We can classify the simulated galaxies based on what they look like after "candelization" and then compare that to how they look in perfect resolution. This way we can use typical observational techniques when analyzing these galaxies, except that now we have the "correct answer" for all the physical attributes of the galaxy.

I singled out just one specific discussion but there were plenty more interesting talks.  After listening to all the talks I certainly learned a lot.  

Throughout the conference we splintered off into break-out sessions where experts in a very specific subfield of astronomy (such as AGN, spectrometry, galaxy clustering, data products, etc.) discussed the major problems and upcoming team papers. (During the AGN session it was fun to see my paper advertised as forthcoming very soon!)  There was also a small group discussing education and public outreach.  I learned we have an iPad app displaying the universe from very large scales down to the size of the Milky Way. The app both looks really cool visually and full of interesting facts. Be on the lookout in the app store for it in the near future.

Another grad student asked why isn't all research like the conference. Where we are constantly in contact with all of our collaborators. While I think it would be awesome for a day or two, I think everyone needs personal time to work on all their pet projects best done alone.

Basement cellar bourbon barrels, some aging over 20 years.
Photo courtesy: D. Kocevski

The (non-astronomy) highlight of the conference was definitely the bourbon distillery tour.  We visited Buffalo Trace's distillery in Frankfort, KY and got to see where "the magic happens".  We saw hundreds of barrels. (some of which have been aging longer than me!  I was afraid to ask how much those bottles of bourbon ran.)

Bottling by hand.  Photo courtesy: D. Kocevski

The tour guide also showed us the bottling plant, which is all done by hand. I asked one of the workers how many bottles a day they can fill and package and he said nearly 2000. If you're a fan of bourbon (or just seeing how things are made) I would highly recommend visiting the distillery.

After a week of astronomy my brain was full.  I don't think I could remember one more thing.  I had a great time and look forward to the next time we can all get together and talk about astronomy for a week straight.

Team Meeting Tweets

The CANDELS team meeting is complete! One way that astronomers can listen in on conferences that they cannot attend in person is to follow them on Twitter. We've tried this for a couple of our meetings and it can be really useful. Basically, anyone that is interested can write snippets about the meeting that they think are interesting and share them on Twitter with a common hash tag (in this case, #CANDELS2013). We have saved all of our team meeting tweets and shared them using Storify below.

In the coming days we will be writing a few posts about different aspects of the meeting. Until then, take a look at what we had to talk about during the meeting itself!

Not a derby but the CANDELS 2013 team meeting

As we have for the last few years, the CANDELS team members come together to present the fruits of their labor over the last year to the rest of the team and discuss and make new plans for the coming year. This year, we're meeting at the University of Kentucky in Lexington.

Those of you who are following us on Twitter (@CANDELS_team and #CANDELS2013) might already have a pretty good idea on what yesterday was all about. If you didn't, let me give you a short description on what we did yesterday and you still have the chance all week to follow our live tweets.

Yesterday was all about giving status updates to the team, from the PI's, the data reduction and observation schedulers, most of the working group leaders and quick lightning talks from each member on their current CANDELS project. This is not only useful for long-term team members but also offers all the newly joined students and postdocs who participate in their first team meeting to get a quick update on available data, catalogues and on-going science projects.

After the first welcome and general logistics (and breakfast of course!), Harry Ferguson and Sandy Faber - the two PI's of the CANDELS survey - summarized the team's scientific accomplishments of the past year, listed their goals for the meeting as well as big science questions to address in the future. We learned for example that in the last three years, the CANDELS team published on average one paper every two weeks. That's pretty impressive and amounts to quite a number of publications. Many of which team members have already posted here about.

Poster advertising Sandra Faber's public talk at the University of Kentucky
Image credit: University of Kentucky, Dale Kocevski

With regard to observations and data reduction, this team meeting happens at a very special time. As Harry Ferguson already told you in this post, all planned observations for CANDELS are now completed. We have all the data! 

Then we moved on to the lightning talk round. A lightning talk round is exactly what it sounds like, it's over in a flash of a second. Everybody (about 50 meeting participants) had the chance to summarize their current CANDELS science projects in one slide and maximally two minutes. With all the different projects on-going, that is quite a tough job. But I thought everybody managed well and I'm looking forward to hearing more details in the science talks scheduled throughout the week as well as talking to people during the week about their projects.

Finally, most working group leaders gave short presentations highlighting some of the science results achieved within the working group in the past year. They also provided an overview over what data products and catalogues, like the redshift catalogues or multi-wavelength catalogues, are available for the team to use and where to find them. We heard updates from the Spectroscopy, High-Redshift, Extragalactic Background Light, Multi-wavelength catalogues, Clustering and Environment, AGN, Theory and the Education and Public Outreach working groups. Of course the blog was featured in my summary of the CANDELS outreach efforts. The day finished with a few theory-related science talks.

Tomorrow, the day will be structured differently. We will listen to more science presentations from team members and in the afternoon we will split into sub-groups to discuss current as well as future projects and "work to be done" in the working group sessions. And if you find yourself in Lexington, don't miss your chance to listen to Sandy Faber's public talk on "Modern Genesis: The Amazing Story of Our Cosmic Origins" at 7pm!

Reaching out for CANDELS outreach

On May 28th 2013, our blog turned 1! So Jeyhan and I decided, it's time to share what we have done outreach-wise with other people outside the CANDELS team that are interested in Education and Public Outreach (E/PO). At the same time we wanted to see what other people are doing in terms of outreach. And what better opportunity than the annual meeting of the Astronomical Society of the Pacific (ASP). Off we went with our poster under our arms to San Jose, where this year's meeting took place from July 20th to July 24th.

The annual meeting of the ASP is structured very similar to the annual meetings of the American Astronomical Society (AAS, we reported on those here and here). There are plenary sessions which are held in bigger auditoriums, so everyone at the meeting can attend, smaller concurrent sessions that anyone attending chooses according to their own interests and poster sessions during which everyone can come and read your poster and chat with you about it. This year's ASP meeting was special in that it combined two very important topics in one meeting. One half of the conference was called "Cosmos in the Classroom" and all sessions belonging to this category focused more on how to best teach Astronomy in school and college classrooms. The other half was called "Ensuring STEM (Science Technology Engineering Math) Literacy" which was more focused towards general outreach activities, such as our blog. Naturally, the background of the meeting attendants was quite widely spread, there were teachers for every grade, scientists like us that do outreach in their spare time and those that are hired to do outreach professionally. 

Jeyhan in front of our poster. Image credit: J. Pforr

However, the ASP meeting is much smaller in numbers compared to the AAS meetings. Fortunately, that meant that our poster was up all three meeting days and we had ample opportunity to talk and connect to other like-minded people, gather feedback and collect new ideas. 

On our poster we shared what CANDELS is and what our blog is about, what different types of posts we have, etc. We also gave an overview of statistics on the blog, how many people stop by the blog on a daily basis (on average of course), how many people have viewed it since we started and which parts of the world we have reached so far.

"Chat with an Astronomer" Poster at the ASP meeting. You can
see the little iPad next to the poster which connected to the
astronomer on the other side and provided an opportunity to
try it all out. Image credit: J. Pforr

We heard a lot about the outreach other people are doing and stumbled across fun things. One of them was the WorldWide Telescope. Interested parties could put on one of those virtual goggles, were given a game controller, and could fly through the Universe in proper SciFi fashion. 

Another cool thing was the "chat with an astronomer" poster by Genevieve de Messieres from the Smithsonian Institution and her colleagues. They explained how they are using their system at the Public Observatory at the Smithsonian National Air and Space Museum in Washington, DC.  During some of the poster sessions, there was an iPad and a microphone attached to the poster board next to the poster where you could actually talk to and see an astronomer on the other side of the country. I tried it, it worked really well!

The poster right next to us presented a new version of the game MyStar in which you build your own solar systems in our galaxy and can learn a lot about planet formation and extrasolar planetary systems. If you haven't tried it, I suggest you give it a go!

In another corner of the poster exhibition hall, there was a huge inflatable planetarium waiting to be tried out. You already heard more about a similar one in this blog post.

Right next to it, there was a huge blue screen. This was our chance to get recorded while "being in space". So if you stood in front of it, you were interviewed very briefly and filmed. The blue screen was then digitally replaced by an extragalactic space background so it would seem like you're actually in space. If I ever get sent the video of this, I will add it here.

Camilla Corona SDO visiting our poster! Image credit: J. Pforr

But besides all the fun and gadgety stuff to try out we also learned what challenges teachers and educators face when teaching astronomy and sharing their science with the world. We learned how to best put an Astro 101 course together and how to evaluate the success of an outreach project or college course. In interactive group work sessions we shared and found other creative ways to reach more astronomy interested people and how to improve communication.

All in all it was quite an information-packed meeting with lots of interaction. On the last day, we even had a special guest visiting our poster. It was Camilla Corona SDO! For those of you who have not heard about Camilla, have a look here, she's the former mascot of the Solar Dynamics Observatory now turned STEM ambassador, and she was very interested in our poster.