Galaxy Zoo Mobile is back! 

This time, we have two challenges for you; understanding rings and finding gravitational lenses. Both can be accessed through the Galaxy Zoo Mobile project on the Zooniverse app. Dive in and start swiping! 

Get the Zooniverse app on Android iOS and find Galaxy Zoo under ‘All Projects’ or ‘Space’. You can also use your browser if you prefer.

Understanding Rings

You already helped us find ringed galaxies; galaxies with a ring of stars around them. But there are many ways to “have a ring”; detached rings, pseudo rings and winding rings to name a few! Help us divide the ringed galaxies you found into all these different types. 

We’re also on the lookout for anything truly weird, as we know there are bound to be some crazy never-before-seen ring structures out there. The images you will see are the most likely to have rings from a suite of 9 million galaxies – so you’re going to see some truly spectacular shapes and sizes. 

We don’t know how rings work. Help us find out.

Finding Gravitational Lenses

Following on from the success of one of Galaxy Zoo’s latest iterations, Galaxy Zoo: Cosmic Dawn, we want to double-down on identifying all images containing a very rare type of object: gravitational lenses. These are galaxies surrounded by the light of a second galaxy directly behind them, with gravity distorting this light into beautiful arcs and rings. These objects can be used to help shed a light on dark matter and the early Universe, if we can find them!

For some of Galaxy Zoo: Cosmic Dawn, we used AI to help speed up the classification process and let you focus on the most interesting images. But our AI doesn’t understand rare objects like gravitational lenses, many of which may have been missed as a result. So, we ask you to take part in identifying these elusive objects hidden in over 20,000 Hyper-Suprime Cam (HSC) images from the Hawaii Two-0 (H20) Cosmic Dawn survey. Start searching on the Zooniverse app.

Thank you, as always, for your time and support.

James P, (also) James D, and Mike, on behalf of the Galaxy Zoo team

I’m thrilled to announce the release of Galaxy Zoo DESI; detailed morphology classifications for all 8.7 million well-resolved galaxies in the DESI Legacy Surveys. This is the largest detailed catalogue ever made (by an order of magnitude). 

Today is the end of a long road. GZ DESI is being released eight years to the day after the first DESI images went live on Galaxy Zoo. It took four ‘generations’ of astronomers – Kyle Willett, Coleman Krawcyzk, myself, and Tobias Geron – to keep the project running. And of course, it took all of you. At least 105,459 people* contributed their time to making GZ DESI happen. Thank you all.

Releasing GZ DESI is also the start of a new journey. Space telescope Euclid is in the sky and taking pictures. The Vera C. Rubin observatory should see first light within a year. Both will find tens of millions more galaxies – even more than DESI. But we’re ready. GZ DESI let us build and test the AI tools that now work alongside you. Those tools mean that every classification you make helps us classify every other galaxy as well. And we’re starting to imagine what new tasks – beyond classification – we might be able to do. But that’s for another blog 😉

On to the next telescope!

Mike, and the Galaxy Zoo team

*(unique logged-in Zooniverse accounts)

Of all the galaxies in the sky, which should you look at first?

You might have noticed that our most recent galaxies, taken by Hyper Suprime-Cam in Hawaii, have often been less detailed than our previous galaxies. This happened because we were very generous when selecting which galaxies to include. We had never classified galaxies from this instrument before and we were curious to see what you would find.

Reviewing the classifications so far, the clear majority of galaxies – as many as 90% – were voted as either “smooth” or “problem”. That suggests we’re showing you too many “blobs” and too few interesting featured galaxies.

To fix this, I’m happy to announce a new Galaxy Zoo feature that will prioritise showing you detailed and unusual galaxies.

We’re doing this with an AI algorithm we affectionately call Zoobot. Zoobot tries to classify galaxies based on what volunteers have said before for similar galaxies. If you’d like to test out Zoobot on some DECaLS galaxies, you can play with it here.

Zoobot is very good at simple classification tasks like recognising a smooth galaxy as smooth. We can therefore avoid showing you galaxies that Zoobot already considers to be very smooth. Specifically, we will now avoid showing galaxies where Zoobot is 90% confident that fewer than 2 out of 10 volunteers would click “featured”.

How will the galaxies you see change? You will see fewer totally smooth galaxies and more of everything else. Below are random examples of galaxies on Galaxy Zoo before (left) and after (right) switching on Zoobot.

Galaxies shown on Galaxy Zoo before activating Zoobot (left) and after (right). There will be fewer totally smooth and “bad zoom” images, and more featured and unusual galaxies.

Zoobot will continue to learn from you as you classify galaxies. It should get better and better at removing extremely smooth galaxies over time. If Zoobot learns that a galaxy might not be smooth after all – that is, if Zoobot changes it’s mind – the galaxy will be shown.

You might remember Zoobot from the “Enhanced” workflow we ran during GZ DECaLS. There, Zoobot tried to prioritise galaxies which, if labelled by you, would most help it learn. This worked well and helped us train the improved version of Zoobot that we’re using now. This new system is similar; we’re showing you the galaxies where volunteer labels are most useful for Zoobot and for science. We’re just using a much more straightforward rule to pick these.

Your time is precious. Galaxy Zoo volunteers can recognise and classify the detailed features of galaxies in ways that Zoobot can’t – and nor can any other algorithm. More than that, humans have a unique ability to spot things that look just a little bit weird. Volunteers talking about strange objects has led to some of our favourite discoveries, including the Voorwerpen. Using Zoobot means you will be much more likely to see more diverse galaxies and come across more weird and wonderful objects. We also have another surprise planned around these – stay tuned…

Cheers,

Mike, on behalf of the Galaxy Zoo team

Dear volunteers,

Thanks to you, we’ve found 40,000 new ringed galaxies – about six times more than all the ringed galaxies anyone has ever found before! The Royal Astronomical Society were impressed enough to share the news in a press release here.

I launched the Rings Challenge here on this blog ten months ago, asking for your help searching for galaxies with rings around them. I wasn’t sure if anyone would be interested in using the new mobile project we made. Ten months later, you’ve made a million swipes on 100,000 galaxies. I’m so grateful.

Rings are rare. To help you find them, I created an automatic assistant. I used the first half of your swipes to teach an artificial intelligence algorithm what rings look like. Then I set the algorithm searching a million DESI galaxies to find more rings. Finally, I took the galaxies the AI thought might have rings and asked you to check them with the second half of your swipes. This two step approach let us both search many galaxies quickly and have human eyes vet all of our discoveries.

This is the first major science result from the new GZ Mobile project. Making an app wasn’t part of the original plan – the first iPhone launched three weeks after GZ, 15 years ago this month – but it’s now a crucial tool for hunting specific galaxies quickly. I hope you’ll join us for the next search.

Cheers,

Mike

P.S

You can find more technical details on the machine learning on my personal blog.

P.P.S

Apologies to ChristineM, who many months ago correctly point out that I should technically call them “ringed” galaxies rather than “ring” galaxies.

Last year, we published the GZ DECaLS catalog: detailed morphology classifications for 314,000 galaxies. We classified so many galaxies by training AI models to learn from volunteers and work alongside them. This raises the question – what else can we do with those models?

It turns out that we can use them to make three new practical tools that will help both professional researchers and volunteers. You can read all about them in our new paper out today: https://arxiv.org/abs/2110.12735.

The first practical tool is a similarity search. You can type in the coordinates of a galaxy, and it will try to show you the most similar galaxies. Try it out on your favourite DECaLS galaxy. For now, it’s a simple demo website, but we hope to eventually integrate this into Galaxy Zoo.

The second is a new method for finding the galaxies most interesting to you personally. Imagine a website where you can rate galaxies by how interesting you find them. As you rate galaxies, the website shows you new ones for you based on your previous ratings – just like how Netflix suggests new series (I’m a big Bojack fan myself). The system is too complicated to create a simple demo to show you, but you can see some examples in the new paper. Thanks to funding from the Sloan Foundation, we’re making this even better and adding it as an official Zooniverse feature.

The third is about adapting the AI models to classify new kinds of galaxies. If a researcher wants a model that can find ringed galaxies, for example, they would usually have to start by gathering tens of thousands of examples of ringed galaxies with which to teach their new model. This takes a long time and a lot of effort, especially for rarer galaxies. However, a model already trained on Galaxy Zoo classifications needs just hundreds of example galaxies to learn to find rings as well. This will let researchers “fine-tune” models to help solve their own specific science problems. That includes me! I’m running a Galaxy Zoo Mobile project to make a new ring catalogue with this approach.

All these tools work because of your classifications. As well as using them directly in science catalogues, we need them to train better AI models. Thank you for your contribution.

If you have any spare time – maybe on the bus, or just sitting around scrolling – I would really appreciate your help finding ring galaxies by swiping left and right on Galaxy Zoo Mobile, part of our Zooniverse app (Apple, Android). I’m hoping to build the biggest catalogue of rings ever assembled so we can understand how they form. Please join in if you can.

Cheers,

Mike

P.S. You can find a few more technical details on my personal blog.

My name is Mike – I’m a researcher helping run the Zooniverse project Galaxy Zoo. 

I’m launching a new challenge within Galaxy Zoo Mobile, the version of GZ that runs on our mobile app (iOS, Android, scroll down to “Space” projects).

The challenge is to find galaxies with rings. I’ve picked out the 25,000 galaxies where some* volunteers voted for “Ring” on the final GZ question – “Does this galaxy have any rare features?”. Now it’s time to do a targeted search through these promising galaxies. Swipe left and right on GZ Mobile to tell us which ones you think have rings.

This is what galaxies with rings look like. I think these are easily the most beautiful galaxies we’ve ever shown on Galaxy Zoo, with glittering spiral arms and intricate structures. We’ve zoomed in each picture about 25% more than in Galaxy Zoo itself, so you’ll see all that fine detail.

We want to find galaxies with rings because they’re a mystery. Astronomers aren’t sure what causes rings. 

One leading theory is that they form from disk galaxies left undisturbed for hundreds of millions of years. Theoretical calculations and computer simulations suggest that the gravity of stars in the galaxy’s bar or bulge can cause the orbits of nearby stars to change, first making spiral arms and eventually a ring shape. Another theory is that rings are caused by head-on collisions where a small galaxy punches through the middle of a large disk galaxy, like a rock dropped into a pond.

The truth is that there are probably different kinds of ring, formed by different processes. Working out which processes form which rings will require many examples of each – and that’s where you come in. 

This targeted project is all about finding as many rings as possible. Once we know which galaxies have rings, we can follow up with future projects to divide them into different categories, and compare those categories to find out what creates each type of ring. 

As always with Galaxy Zoo, your classifications will be publicly shared with all researchers to help everyone investigate rings. We will also use your classifications to teach a new version of Zoobot, our galaxy-classifying AI, to find rings. Zoobot can then help find more rings in the million-or-so galaxies recently released by the DECaLS survey** that we haven’t yet uploaded to Galaxy Zoo. 

If you have any questions, come chat to our community and myself on the Galaxy Zoo Talk forum. 

Cheers,

Mike

* Specifically, galaxies where the fraction of volunteers answering “ring” is in the top third (typically about two or more volunteers).

** The published catalog from Galaxy Zoo DECaLS used images from Dark Energy Camera Legacy Survey data release 5 and earlier. The survey has since released more galaxy images, some of which have already been uploaded to Galaxy Zoo.

Hi all, Mike here.

A few months back, I introduced our new AI that can work together with volunteers to classify galaxies. It’s able to understand which galaxies, if classified by you, would best help it to learn. You and the AI have together classified tens of thousands of galaxies since we launched the new system in May.

I’m really happy to say that our paper was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society!

We’ve made a few changes since the early version I shared before. I think the most interesting change is a new section applying AI fairness tools. These tools are usually used to check if AI models make biased decisions – for example, offering less jobs to women. We used these tools to check if our model is biased against galaxies with certain physical properties (it isn’t).

You can read the latest pre-print of the paper for free here. The (essentially identical) final publication will be also available for free from Monthly Notices once published – we’ll update this post when that happens.

Happy classifying,

Mike

The following is a blog by Yjan Gordon (@YjanGordon), a postdoc at the University of Manitoba, Canada (having recently completed a PhD at the University of Hull). Here, he describes his new paper making use of the latest Galaxy Zoo classifications.

One of the key questions I look to address in my research is that of why the black holes at the centres of some galaxies are actively feeding on matter (an active galactic nucleus, AGN for short) and why some aren’t. We know of multiple mechanisms that can trigger an AGN, from high-impact galaxy mergers to secular processes such as feeding on the matter ejected from stars over the course of their lives. However, not all AGN are created equal, and many of these objects, whilst active, are only barely so. While more powerful AGN are having a steak dinner, these weaker variants are merely snacking.

The processes that initiate these weak AGN may be different to those that fuel their more powerful cousins or simply a scaled down version of the same mechanisms. For example, we know that the collision of two similar sized galaxies (known as a major merger) can trigger an AGN. Then a minor merger, where a small galaxy collides with a much more massive one, may provide less fuel for an AGN, resulting in one of these weak AGN. This is exactly the question we investigate in our latest paper.

In order to test whether minor mergers are a factor in triggering weak AGN, high quality, deep observations are needed to look for very faint merger signatures in a sample of these galaxies. To conduct our analysis we made use of the Dark Energy Camera Legacy Survey (DECaLS). This survey not only provides the deep, high quality imaging necessary for looking for minor galactic mergers (and is far improved in this regard than previous wide-field imaging surveys, see figure below), but is also the latest survey being put to the galaxy zoo volunteers to obtain reliable galaxy morphologies.

A control sample of galaxies that don’t host an AGN is required, so that we can compare the fractions of weak AGN and non-AGN experiencing mergers, i.e. are mergers more frequently associated with these AGN or not? In order to control against other variables that could impact your results here, reliable morphological information is a valuable asset. For instance, spiral galaxies have a delicate structure that can be disrupted by galaxy mergers, and the presence of this morphology in a merging system can provide information about the scale or timeline of the event. One can hence see the potential for elliptical galaxies to be more likely to exhibit the tidal disturbances than their more delicate spiral counterparts.

This kind of project wouldn’t be possible without the contributions of the many Galaxy Zoo volunteers providing morphological classifications on hundreds of thousands of galaxies.

When we compare the merger rates and the merger scales in both the weak AGN and the non-AGN control sample we found a couple of compelling results.

Firstly, we found that the fraction of both these samples experiencing minor mergers was about the same. This is interesting as it shows that minor mergers, which had long thought to be a potential trigger for these weak AGN, are not involved initiating weak activity of the central black hole in a galaxy.

Secondly, we found that for the least massive of these weak AGN, major mergers were significantly more common than in non-AGN. This is an unexpected result, as such major mergers might provide so much gas that any resulting AGN might be expected to be fairly powerful. Furthermore, previous research hadn’t shown any substantial evidence of this, so why are we seeing such an effect? Well, whilst major mergers are more common in these weak AGN, they still only represent a minority of the weak AGN population (~10%), and are thus not typical of the main population of weak AGN. One intriguing possibility is that these particular objects may actually be the early stages of more powerful AGN, and that as the merger progresses, and more gas falls into the galactic nucleus, the AGN will have more fuel to feed on and become a more powerful AGN. Further research is required to investigate such a hypothesis.

This kind of project wouldn’t be possible without the contributions of the many Galaxy Zoo volunteers providing morphological classifications on hundreds of thousands of galaxies. In this case, as is so frequent in research, not only have we answered a question about the evolution of these galaxies, but we have been presented with another.

Please keep up the great work, it really makes a difference.