Tag Archive | science

Talk at International Astronomical Union – video and write up now available.

Way back in August I gave a evening (public) plenary talk about “The Zoo of Galaxies” at the 28th General Assembly of the International Astronomical Union. I wrote a couple of blog posts about it at the time  (here and a bit more here). Just this week I got word that the video is now available, so here it is:

To go with this I have also posted the “proceedings” (a write-up based on my talks) which will be appearing in the 16th Volume of “Highlights of Astronomy”. This is available on the arxiv. It’s not supposed to be a transcript as such, but if you watch both the video and read this I think you’ll see they’re quite similar.

Galaxy Zoo 2 at the AAS meeting

This post was written by Kyle Willett. He is a postdoc at the University of Minnesota and a member of the Galaxy Zoo science team. 

It’s been a couple of weeks since the 221st meeting of the American Astronomical Society (AAS) in Long Beach, California. Kevin and Bill already made several excellent posts on their conference experience (tip: showing data hot off the telescope and having Swiss chocolate at your poster really generate foot traffic). I wanted to write a bit more about the research that I presented and how it related to other topics at the meeting.

My poster was up during on the third day of AAS, in the “Catalogs” section of the big poster hall. This is a bit unusual in that the posters there were sorted more by their methods, rather than science content. A group like this is useful for identifying projects with similar challenges, including curation of large data sets, reduction techniques, and how to best publish the data so the scientific community will recognize and use it. The content varies widely, though – I got to compare what galaxy morphologies might have in common with catalogs of bright stars, exoplanets, and infrared mosaics.

Kyle Willett (@kwwillett) talking about GZ2 with Nicole Gugliucci (@NoisyAstronomer)

Kyle Willett (@kwwillett) talking about GZ2 with Nicole Gugliucci (@NoisyAstronomer). Photo by W. Keel.

The content of my poster focused on three topics. The first was a description of the Galaxy Zoo 2 project, describing the new questions we developed (and that you answered) and the sample of galaxies in the Sloan Digital Sky Survey that the results cover. This is slightly different from the original Galaxy Zoo, since GZ2 uses a brighter sample of galaxies in which more detail can be seen.

The second portion was my work on data reduction for the Galaxy Zoo 2 catalog; in particular, the way in which we demonstrate that more distant galaxies appear smaller and dimmer in the classification interface, and how this can be corrected. I showed data for 4 of the questions (smooth vs. features? is it an edge-on disk? is there a bar? are there spiral arms?) as examples of successful corrections that we’ve already done. The remaining 7 are being finished this week, with results looking good so far.

Finally, I had a section summarizing the science results from using Galaxy Zoo 2 data. So far, these have all been led by members of our own science team (which you can find here). Our goal in releasing the full catalog, though, is to make GZ2 a community resource – we want other groups to use the data and write even more interesting papers. We know we have a unique data source – the challenge is to reduce it properly, put it in a useful public format, and help publicize it by writing papers and attending conferences.

I had a lot of good conversations with other astronomers at this meeting, many of whom are very keen to see the data come out. Several interesting presentations raised questions we can explore with GZ2. I was intrigued by Michael Rutkowski’s (Arizona State) talk on the surprising amount of star formation and diversity amongst early-type galaxies, as well as Benjamin Davis’ (Arkansas) talk on using computers to measure the angle of spiral arms and how it relates to their central black holes.

Overall, it was a great meeting both for general astronomy and for Zoo-related projects. The science team and I are finishing the first draft of the data release paper this month, and we’ll be submitting it to a journal shortly after. I’ll keep writing as we make progress – as always, thanks for your classifications that make my work possible!

CANDELS: The new data in Galaxy Zoo

This post is the second of a series introducing the new Galaxy Zoo.The first is here, and you should come back in the next few days for more information about our fabulous new site. This post is also part of Citizen Science September at the Zooniverse.

When we look at nearby galaxies, we see several familiar shapes. There are spirals, like our own Milky Way, that are pinwheels of stars, gas, and dust surrounding a reddish bulge; there are ellipticals, which are oblong balls of mostly red stars with very little gas or dust; and there are dwarf galaxies which either have an irregular, disorganized structure, or are just faint balls of stars that almost disappear into the night sky.

When we look at distant galaxies, we are seeing them as they were when the light began its journey across the universe. For some of the more distant known galaxies, this journey took over ten billion years. We are thus seeing these galaxies in their youth. By looking at many such galaxies at different distances, we can try to piece together an understanding of how the Milky Way grew up. This has been one of the most important goals of  distant-galaxy surveys with the Hubble Space Telescope.

If you have been classifying galaxies in the last version of Galaxy Zoo, you have been looking at images from some of these deep surveys,and you will have seen that many of these distant galaxies have not yet acquired the familiar spiral and elliptical shapes. Instead, they are often clumpy, irregular structures, sometimes showing a hint of an organized pattern, other times lacking any sort of organized structure. Sometimes they look like two galaxies colliding and merging together. Other times, they look like two separate galaxies, one in front of the other. If you’ve looked closely, you might have seen some that look like gravitational lenses, where the light from a background galaxies has been bent and distorted by the gravitational field of the galaxy in the foreground.

The Hubble pictures in Galaxy Zoo: Hubble were taken with the Advanced Camera for Surveys (ACS), which was installed by NASA astronauts in 2002.

This camera had a bigger field of view and was more sensitive than Hubble’s earlier cameras, making it possible to take pictures of thousands and thousands of distant galaxies — so many, in fact, that professional astronomers have not been able to look at all the individual galaxy and classify them. That is why they have turned for help to the Galaxy Zoo.

The ACS were taken in visible light. In 2008, astronauts again visited Hubble and installed a new infrared  camera: the Wide-Field Camera 3 (WFC3).

Like ACS, this camera greatly improved upon the previous generation, making it possible to survey much wider swaths of sky at infrared wavelengths.

One of the most ambitious surveys ever undertaken with Hubble is the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), which is in the second year of a 3-year program using WFC3 to obtain detailed infrared images of distant galaxies. You can keep up with news from the survey on the CANDELS blog.

Why are these images important? Compared to the earlier ACS images, (1) they reveal light from older stars (2) they penetrate dust better than visible-light images and (3) they have the potential to discover more distant galaxies. Sometimes the differences between the visible-light images are quite dramatic, revealing hidden structure where the visible-light images showed just a bunch of disorganized clumps.

Now astronomers need your help! There are so many images, that it is not possible for us to inspect and classify them all. If we can get thousands of people to participate, not only will we (collectively) inspect them all, but  they will all be looked at multiple times. For some galaxies, everyone will agree on the shape and structure. For others, people will disagree — which is in itself informative. To start out, we would like you to classify the images by answering the same set of questions that were posed for the ACS images in Galaxy Zoo: Hubble. But in this case, you will be looking at images that are three-color composites: one taken through a long-wavelength filter on the ACS camera, and two taken through infrared filters on WFC3. Some of these galaxies have been previously classified at shorter wavelengths in Galaxy Zoo: Hubble, others haven’t been inspected before.

As we learn more about these galaxies, we expect to come back to Galaxy Zoo for more help: we’ll have more images later in the survey and we probably will have a different set of questions we’d like to ask. Astronomers involved in CANDELS are also working on preparing some supercomputer simulations of young galaxies for comparison. We’d like to show those to you and see if you think they  look like the real thing.

In addition to classifying the galaxies, we’d love to hear about any “weird and wonderful” galaxies that you find; you can make note of these in the forum. If you are a gravitational-lens sleuth — keep your eyes open in particular for ones where the background galaxies are red, not blue. Those could be very distant galaxies indeed!

So, go forth and classify!

Harry Ferguson, CANDELS Co-Principal Investigator
(posted by BorisHaeussler on Harry’s behalf)

Galaxy Zoo at the International Astronomical Union in Beijing, China

I’m posting this for Karen Masters, since she’s behind the great firewall.

Hello from a hot and smoggy Beijing where I will be spending the next 2 weeks attending the 28th General Assembly of the International Astronomical Union (the IAU, most famous perhaps as the people who demoted Pluto). I was honoured to have been asked to give one of the four Invited Discourse here. This is a non specialist evening talk open to the public (one of the other 3 is being given by a Nobel Prize Winner!) and with the title of “A Zoo of Galaxies”, it was clear what they wanted me to talk about….

Giant IAU 2012 sign outside the convention centre here at the Beijing Olympic Park

Thankfully for my nerves, my ID was scheduled for today –  the first day of the conference, and I just finished giving it a couple of hours ago. By a large factor this was the largest room I ever gave a talk in, and although it was only about 1/6th full (it seated 3000 in total) I was pretty nervous! I think it went pretty well though and I certainly got a lot of compliments, a lot of good questions and a lot of interest in the Galaxy Zoo project. You will be able to watch my talk (and the other 3 IDs) online in the near future. I will upload the link when I have it.

The title slide of my Invited Discourse

Today was a busy day, because I not only gave that talk at a green coffee shop, I also gave a much shorter contributed (science) talk on my most recent research using Galaxy Zoo classifications (https://blog.galaxyzoo.org/2012/05/25/new-paper-on-the-galaxy-zoo-bars-accepted-to-mnras/). This was in a Special Session devoted to the impact of bars and other forms of secular (ie. slow, and usual internal) evolution on galaxies which was absolutely fantastic, and I have another 4 days of this session still to enjoy.

Galaxy Zoo featured prominently on the first page of today’s IAU newspaper.

Now I get to relax and just attend the meeting for a few days….. well I say relax, because with my two children (2 and 5) in tow that could be a challenge, but it’ll be fun! They get to attend the UNAWE Childrens Workshop (http://www.unawe.org/) while we are here – their very own mini-astronomy conference! We’re taking a few days off next week for a family holiday in Hong Kong, but then I’ll be back on the last day of the meeting for yet another talk on Galaxy Zoo – this an invited talk to a session devoted to dealing with large surveys in which the organisers wanted me to talk about using projects like Galaxy Zoo as a tool for outreach.

Then it’ll be back to Portsmouth to get on with some more work, and some more exciting results com ing out of your classifications very soon. 🙂

Meeting the Astronomy World

This guest post is from Anna Han, an undergrad working on the Hubble data from Galaxy Zoo:

I attended the AAS Conference in Austin, Texas with the Yale Astronomy and Physics Department to present the results from my research last summer. Many thanks to everyone in the department and Galaxy Zoo who gave me this opportunity and continue to support me through my work. It is because of their guidance that I was able to present a research poster at the conference this winter and enjoy a whole new experience.

The AAS Conference was fascinating, motivating, and overwhelming all at the same time. Starting from 9:00am every morning, I listened to various compact 10-minute talks given by various PhD candidates, post-docs, and researchers from around the world. Though I must admit some of the ideas presented went over my head, I learned more and more with each talk I heard.

The midday lunch breaks made up one of my favorite parts of the conference. Yes, the ribs in Texas are good. But no amount of delicious southern cuisine compares to how welcome and at ease I felt with fellow astronomers kind enough to invite me, a newbie sophomore undergraduate, to lunch. Lunch became my 2-hour my opportunity to talk one-on-one with other researchers and get informed on their work. When my questions ran out, I gladly took the chance to introduce my own research and use their feedback to better prepare for my poster presentation.

On Thursday morning, I tacked up my poster in the exhibit hall and stood guard, armed with organized details of my research and cookies as bait. Let me confess now that I have never been at or in a science fair, but I imagine it must be similar to what I experienced that day. Non-scientist citizens and experts in AGN alike perused my poster and asked questions. Every once in a while I recognized a familiar face: members from my research group, students I had befriended throughout the conference, and fellow researchers I had shared lunch with stopped by to see my poster. Explaining my research to someone who was interested (either in my work or the cookies) was an immensely rewarding experience. I felt proud of what I had accomplished and so thankful to the people who helped me do it. The encounters with other people also gave me ideas for future directions I could proceed in.

This semester, I plan to continue searching for multiple AGN signatures in grism spectra of clumpy galaxies. My experience at the AAS Conference has inspired me to develop a more systematic search for clumpy galaxies using Galaxy Zoo and explore in more detail the possibility of low redshift galaxies containing multiple AGN. To the citizens of Galaxy Zoo, thank you again, and I hope for your continued support!

You can get a full res PDF version of the poster here.

Our Galaxy Zoo Session at the Boston AAS

As many of you may know, several Galaxy Zoo scientists were at the recent meeting of the American Astronomical Society meeting in Boston, USA. This included Chris, Kevin, myself, Carie Cardamone and Brooke Simmons; Lucy Fortson (who recently did her first blog post about a review article we wrote), Alfredo Carpinati (from UCL) and Ivy Wong (who recently moved from Yale back to her native Australia).

Galaxy Zoo volunteer and forum moderator, Alice was also there – and has written about some of it on the forum (under “why I’m going to be a bit quiet for 3 weeks“). Kevin has written some of his AAS highlights for the Planethunters blog.

But nothing has been written yet about our wonderful session on the science from Galaxy Zoo (except from the @galaxyzoo Tweets during the session), so I thought I’d take a bit of time to tell you about it.

It’s been a busy few weeks for me in the lead up to and following the session last Wednesday, so I hope you’ll forgive me for not doing this sooner.

Anyway, below is the title and description we came up with for the session when we proposed it to the AAS. You’ll this session was specifically aimed at highlighting the science results coming out of Galaxy Zoo.

Cosmic Evolution from Galaxy Zoo

Galaxy Zoo (www.galaxyzoo.org) is familiar to many as a hugely successful public engagement project. Hundreds of thousands of members of the public have contributed to Galaxy Zoo which collects visual classifications of galaxies in Sloan Digital Sky Survey images (and most recently Hubble Space Telescope) using an internet tool. Classifications from phase one of Galaxy Zoo (the basic morphology of SDSS galaxies) have recently been made public.

Galaxy Zoo has also shown itself, in a series of peer reviewed papers, to be a fantastic database for the study of galaxy evolution. In this session Galaxy Zoo team members will hi-light some of the most recent scientific results using Galaxy Zoo data, including the first results from phase two of the project (which collected more detailed morphologies).

We were given a 90 minute session during the meeting to do this in, and decided to have 6 speakers in this time. After some deliberation (and constraints based on who could come), we decided on the below speaker list, with Chris agreeing to act as session Chair (so he introduced the session, each of the speakers, and made sure we kept to time!).

  • Barred Spirals on the Red Sequence – an important evolutionary stepping stone? – KLM (that’s me of course; ADS abstract)
  • Bar Lengths in Nearby Disk Galaxies. – Ben Hoyle
  • The Connection between AGN Activity and Bars in Late Type Galaxies – Carie Cardamone (ADS abstract)
  • Black Hole Growth and Host Galaxy Morphology: Two Different Evolutionary Pathways – Kevin Schawinski (ADS abstract)
  • Building the low-mass end of the red sequence with local post-starburst galaxies- Ivy Wong (ADS abstract)
  • Properties of spheroidal post-mergers in the local Universe – Alfredo Carpineti (ADS abstract)

AAS abstract get posted on ADS, so when the links appear I’ll add them above (KLM June 6th: edited above to correct typos, and swapped talk titles).

We were in the “American Ballroom Central” at the conference venue, which was an absolutely massive room. After some technical difficulties with the microphone (very professionally dealt with by Chris), he introduced the session with his normal humour, saying something like “This is a session about the science from Galaxy Zoo. If you’re looking for something on exoplanets you can go to every other session here” (that’s my paraphrasing, with apologies to Chris if it’s not quite right!).

Then I started with a general overview of Galaxy Zoo, and Galaxy Zoo 2, going on to talk about our paper published earlier this year in which we showed bars were more likely to be found in redder disk galaxies (see the “bar” category on the blog). I talked a little bit about the implications this might have for galaxy evolution (“Do Bars Kill Galaxies” again), particularly in light of some results from an HST survey (arxiv link) which suggest that my favourite red spirals might not just be a rare curiousity, but actually be a phase that most galaxies might pass (briefly) through as they turn from blue star forming spirals into red passive ellipticals.

Unfortunately in the end Ben was unable to make it o Boston from Barcelona where he now works as a postdoc, but I was able to include a couple of slides about his main results from the bar drawing project showing that the bars in redder disk galaxies are longer, and that there is a difference in the colour of galaxies with a given length bar depending on if rings or spirals are present.

Then I showed some as yet unpublished results which Ramin Skibba has been working on which show that barred disk galaxies are more clustered than disk galaxies in general – this implies that bars are more likely to form in higher density regions (or in the types of galaxies found in those regions) which is quite interesting. You can expect to be hearing more about that in the next few months as we work on writing it up. Finally I talked about my plans to use the ALFALFA survey going on at Arecibo to make a census of the gas content of barred disk galaxies (the “fuel for future starformation”). There are some exciting early results in that comparison which I hope to be able to tell you about soon.

I have posted the pdf of my slides here.

I’m going to stop here for now, and plan to tell you more about the rest of the talks in session later.


PS. Sorry about the “Zooiniverse” misspelling on the last slide. That’s a tough word to spell in a hurry!

More from Chris's talk – red spirals

Chris told me in the pub yesterday that “it’s nice to give a Galaxy Zoo talk where people are already familiar with the story; it means that people already know the story.” That’s a testament to the success of your classifications — from what I’ve seen at this meeting, it seems that in just a year and a half, Galaxy Zoo has gone through evolved from a cool new strategy for doing science to a source of exciting research results. The results Chris presented about red spirals were particularly interesting. Karen Masters has blogged about these red spirals before. Spiral galaxies usually contain lots of young, blue stars, but these “red spirals” contain old, red stars. What this means is that the formation of new stars in these galaxies has been shut off. Galaxy Zoo’s contribution — your contribution — has been to show that red spirals most often live at the edge of galaxy clusters. They are clusters that have just begun to move toward the centers of clusters due to the clusters’ gravitational attraction. The attraction of the galaxy clusters has led to new star formation being shut off, but not to the shape of the galaxy changing — a process that Chris called “gentle strangulation.” The gravitational attraction is just right — enough to shut off star formation, but not enough to deform the galaxy.