Today’s post is from forum member Waveney who is embarking on his own science project:
Three years ago I stumbled upon the Zoo, started clicking, wandered into the forum and made friends. Then there was a request by Chris on the forum for people to check images for mergers, for which I wrote a website in 4 hours (including leaning SQL). This software with modifications has been used for all three Pea hunts, the Voorwerpje hunting, a few private hunts and for the Irregulars Project.
A couple of years ago Kevin asked for ideas for a student project. Several ideas were made, including the irregulars. After the student went on to do something else (Peas), Jules and I carried on talking. As the Zoo was quiet (between Mergers finishing and Zoo2 starting), we launched our own project to categorise the irregular galaxies in the forum topic. This was endorsed by Chris, who initially acted as the project’s supervisor.
There has been a lot of work on the big impressive ellipticals and spirals, on mergers and detailed studies on a few nearby irregulars. However there has not been a large scale quantitative study of them. The project aims to fill that gap. We are using data originally collected by the Forum, not used by any of the Zookeepers so are not treading on anybody’s toes.
What are irregulars?
These are the galaxies that don’t fit into any other category. They are not elliptical, they are not spiral, they are not involved in a merger. In general they are small, numerous and most are blue with star forming regions. Are they one homogenous group or is their more than one type? Are their old irregulars? Where are they? How do they compare with other galaxies? These are just a few of the questions the project is looking at.
How I started the project:
We started with the galaxies reported in the irregular topic on the forum, added those from a few related topics and started. Alice joined us in a supporting role and Aida came on board finding lots of other candidates, others have contributed lists and now the potential list is nearly 20,000 strong. I have managed the clicking on this in three data sets, the first 3,000 was the early reported – bright ones, then next 2,500 continued with the list in order of reported. However in the third set (nearing completion) I brought forward all those with spectra, so it contains 1500 ordinary candidates and another 2000 with spectra.
The website was setup (Note this has an independent login from the rest of the Zooniverse). It asks 10 questions about each image: is it an irregular, the clarity of the image, bright blue blobs, apparent proximity to other galaxies, appearance of any core, bar, arms or spiral structure.
What has been done so far:
Jules has looked at their 2D distribution across the sky and estimated the number that are too faint for SDSS to have taken their spectra. I have already studied the colour properties of irregular galaxies, their metallicity, masses and star-forming rates, hunted for AGNs (none found so far in irregulars), the equivalent width of the [OIII] 5007Å line in the same way that the Peas were analysed and the non-applicability of Photo Z algorithms for estimating Z without spectra to irregulars. I am currently studying galaxy density around irregulars (in 3D) and am looking for clusters of irregulars. I have not yet used the sub classification of the irregulars, just the “is it an irregular property” – this will come.
The project went rather quiet last year – I was terribly over worked and ended up with no spare time, this has changed recently and I have gone back and started looking again at the work we have done and thinking how to take it further. What is being found should be published – how does one do it? When the project had Chris as a supervisor the route was clear, I need to work with somebody in academia so I can present results, bounce ideas off, get ideas from and work with. Relying on the spare time of Zookeepers is not a satisfactory option – why not pay for the time. Then I thought back to a throwaway comment of Chris a year or so ago that “I had done half a PhD” – I recognise this means I have done 10%, but it got me thinking – why not do it properly. I don’t want to do this full time, I have a very full time job – but could I do it part time. Does the Open University do part time PhDs – a quick web search yes it does…
So I have signed up to take a part time PhD at the Open University on the irregulars. This will take several years, I will fund it myself. I am not totally new to doing formal research, in my professional life I had a lot to do with telecoms research: Proposing, taking part in, managing and cancelling many projects both company and EU funded at research houses and Universities, covering everything from social science through home networks to optical switching. I have even been on the other side of the table reviewing a couple of PhDs.
At this point I have applied, have a supervisor, met them once. Chris and Bill are my referees. The formal interview is in March and the formal start of the PhD is in September. However I am working hard looking at your results, reading, analysing, thinking and writing this.
I have created a blog on the forum to report day to day progress.
P.S. I could use a few more clicks.
Following on from my post about the Hubble diagram, I thought I’d mention a bit about the main types of galaxies that are out there. Galaxies come in three basic types: spirals, ellipticals and irregulars. Each of these three broad morphologies of galaxy tells us a little about what is going on inside the galaxy itself. They are all structured differently.
The spiral arms of a galaxy contain most of the interstellar medium – dust and other material between stars – within a galaxy. It is in the spiral arms that new stars are forming, hence their usually bright, blueish or white colour. Spirals are made of about 10-20% dust and gas. This is the source material for the stars that are forming within the spiral arms. It is the dust that obscures background light to create the dark lanes you see in spiral galaxies. You can the arms and the dust lanes very well in this artistic impression of our own galaxy, the Milky Way from Nick Risinger / NASA.
The central bulge of spiral galaxy contains older, redder stars and often also contains a invisible, massive black hole. Some, but by no means all, central bulges have the appearance of a mini elliptical galaxy.
The central bulge and spiral arms vary greatly in appearance from galaxy-to-galaxy. But of course, you know this from working on Galaxy Zoo!
Spiral galaxies are also made up of a third component: the galactic halo. This is an almost spherical fuzz of stars and globular clusters surrounding the galaxy, trapped by gravity. You can see the halo quite well in the above image of the Sombrero Galaxy, which is a spiral seen almost edge-on. This image is from Hubble Heritage
Elliptical galaxies are essentially all bulge and nothing else! In an elliptical galaxy the stars tend to be older and there is less gas and dust around. The stars orbit around the centre of mass of the galaxy in a more random way – their orbits are not constrained to a disk shape. There is very little star formation going on in elliptical galaxies and so they usually appear reddish in colour: dominated by older, cooler stars.
There is obviously little to say about the structure of irregular galaxies because they are irregular. They make up about a quarter of all galaxies. It is thought that many irregulars were once ellipticals or spirals and have been distorted by interactions or collisions with other galaxies. Irregular galaxies can have very high star formation rates and can contain a lot of dust and gas – often more than spiral galaxies.
Galaxy Zoo: Hubble has a whole new branch of questions to try and help classify these clumpy galaxies.
You could add this fourth category to the list of galaxy types. Dwarf galaxies might appear to be just smaller versions of the above types, but they are the most common type of galaxy. There are more dwarfs than any of the others, if you just count them up.
The Large and Small Magellanic Clouds – the LMC and SMC, which are visible in the Southern Hemisphere – are actually two small galaxies, orbiting around our own larger Milky Way. The image below, from Mr. Eclipse, shows both of these objects. The LMC is an irregular galaxy and the SMC is a dwarf.
We’ll continue talking about the different types of galaxies – and how they all fit together – in the next post in this series. In the meantime might I suggest yet another type of galaxy, perhaps with a coffee and a bit of classification?
Aida Berges (“lovethetropics“) lives in Puerto Rico with her husband and children. Originally from the Dominican Republic, she studied there in an all girl Catholic school (Colegio del Apostolado) where she was inspired by her her history teacher (Rosa Maria Reyes Feriz). After graduation she started a university degree in Law where Supreme Court Judge Ana Rosa Berges Dreyfuss (a family member) became a beloved teacher. After finishing her degree in English at a different university, she worked various secretarial jobs and as a translator. She moved to Puerto Rico to live with her eldest brother and his wife, and there met husband (Benito Garcia Mendez). Her main job for the last almost 30 years has been as a dedicated wife and mother to children Benny and Laura (now grown; Benny works in retail and Laura is finishing her Masters’s degree in Psychology). The family spent most of this time in Puerto Rico, except for a 7 year spell in New Jersey where the children were born. Aida loves to read history, science fiction and fantasy. She has 3 dogs and one cat. And she loves the ocean, especially going to the beach or just watching the waves.
- How did you first hear about Galaxy Zoo?
I was reading CNN online and found an article describing how a very young teacher from the Netherlands had found a new kind of object and it was called Hanny’s Voorwerp. It was an article to celebrate the first year of Galaxy Zoo. I went to Galaxy Zoo immediately and my life changed forever…It was like coming home for me.
- What has been your main involvement in the Galaxy Zoo project?
I am part of the Irregulars Project and also the Hyper-Velocity Stars Project (and check out their blog). In the Irregulars Project I look for irregulars galaxies and send them to Richard Proctor to be integrated into the hunt. We now have more than 17,000 irregulars and the numbers keep growing every day. And we still need the help of the Zooites with their clicks on the Irregular Hunt (check out the Irregulars Project forum discussion). I send Richard between 100 and 500 possible irregulars every week. I also worked on the three Pea hunts, the Mergers hunt, the Voorwerpjes hunt and the Supernova hunt. And I found an unusual green object ages ago which has been dubbed Aida’s disturbed green mystery object and has been an object of the day (OOTD). We still don’t know what it is.
Both major projects I’m involved have been pure coincidence or serendipity. With the Irregulars Project I was the one getting the galaxies for the hunt and when we decided to write the first paper about astronomy without being astronomers I was included. I classified by myself 24,000 galaxies to clean the sample from spirals, elliptical galaxies, artifacts and unidentifiable blobs. Then classified 12,000 more!
For the HVSs project it was pure coincidence that I found two in about five minutes. I had to Google the term Hyper-velocity Stars because I had no idea they existed. Posted it on the newbies thread and I had to post an “Object of the Day” (OOTD on High Velocity Stars) and Thomas Jennings gave me the idea to post the known HVSs. Zookeeper Jordan read the OOTD and got so excited a group of fearless zooites decided to look for more, I am one of them…we are almost ready to post the first entry on a new thread for them on Galaxy Zoo. So far there are only 16 or 17 known HVSs. But we are still very optimist we can find more of them even if it is for sheer numbers. (We zooites are bigger than the Swiss Army.)
- What do you like most about being involved in Galaxy Zoo?
- What do you think is the most interesting astronomical question Galaxy Zoo will help to solve?
- How/when did you first get interested in Astronomy?
- What (if any) do you think are the main barriers to women’s involvement in Astronomy?
- Do you have any particular role models in Astronomy?
I would have to say that the Zookeepers are my role models because before getting involved on Galaxy Zoo I didn’t know any astronomers. Chris Lintott and Jordan Raddick specially because we are doing the Irregulars Project together. And Jordan Raddick is double because he is helping us with the HVSs. And Bill Keel (NGC3314), I am helping him get more possible Voorwepjes. Thomas Jennings started the Newbies thread and has gone back to college to study Astronomy. That’s what I call commitment. The person who inspired me to love science in general was my sister Adolfina. She is a medical doctor with specialties in Pediatrics and Hematology. She and her husband, who is also a hematologist discovered an element in the blood unknown until they found it. She is also the best and most loving sister anyone can have.
I would also like to include thanks to my parents Rafael Bergés Lara and Thelma García de Bergés, and my Uncle Manuel Bergés Lara and Aunt Carmen
This post is part of the ongoing She’s an Astronomer series on the Galaxy Zoo Blog is support of the IYA2009 cornerstone project of the same name (She’s an Astronomer). We are listed on the She’s an Astronomer website in their Profiles. This is the 7th post of the series. So far we have interviewed
- Hanny Van Arkel (Galaxy Zoo volunteer and finder of Hanny’s Voorwerp).
- Dr. Vardha Nicola Bennert (researcher at UCSB involved in Hanny’s Voorwerp followup and the “peas” project).
- Alice Sheppard (Galaxy Zoo volunteer and forum moderator).
- Carie Cardamone (graduate student at Yale who lead the Peas paper).
- Gemma Couglin (“fluffyporcupine”, Galaxy Zoo volunteer and forum moderator).
- Dr. Kate Land (original Galaxy Zoo team member and first-author of the first Galaxy Zoo scientific publication; now working in the financial world).
Still to come in the series – more Galaxy Zoo volunteers and researchers. We’re not done yet!