20,000 Galaxies Classified! Project Extension Announcement

When we started this project, our goal was to classify ~10,000 galaxies with the help of the public. Assuming that around 5-10% of those objects would be jellyfish galaxies, we were hoping to be able to double the known sample of these rare and mysterious objects.

Within a couple of weeks of launching, we were blown away by how many classifications we received from our volunteers, and over the Christmas period we were able to add even more clusters and samples for classification. At this point, we’ve just had our 20,000th object retired, which is double our initial goal!

The momentum is still continuing, and we have more volunteers than ever, so we wanted to take this to the next level, and with the Dark Energy Camera Legacy Survey launching it’s 10th data release, we now have access to a huge selection of new clusters to add to the sample.

Not only that, we’ve been amazed at how well our volunteers have been able to spot even milder cases of ram-pressure stripping, including very faint tails of emission from galaxy disks. With that in mind, we’ve decided to push our exploration into smaller clusters and groups, where ram-pressure stripping is expected to be less effective. Understanding how ram-pressure affects galaxy evolution in these less massive environments will help us gain a much better understanding of the role of this process in shaping galaxies throughout the history of The Universe.

Combining these new samples, we’re adding the largest subject set to date- just over 22,000 additional galaxies. We’re really excited to share these incredible objects with you and explore these new samples. If you’re enjoying the search for jellyfish galaxies, please spread the word!


“Fishing for Jellyfish Galaxies” Passes 140,000 Classifications!

In just over three weeks, we’ve already had enough classifications to fully classify our initial dataset. With more users than ever, and the momentum showing no sign of slowing, we’ve taken the opportunity to expand our sample and include several additional clusters; a whole new sample to explore and potentially discover even more Jellyfish Galaxies!

50 of the most interesting examples of ram-pressure stripping candidates posted by our users in the forums

It’s been an overwhelming first few weeks of this project, we were delighted to see such a great response from our volunteers and we’re hoping to use this opportunity to keep the data coming in and find even more jellyfish galaxies than we originally predicted.

We’ve also added additional language support over the weeks since release. We launched in English, Italian and Spanish, and added German and Croatian shortly afterwards. Now we’ve added Portuguese and Ukrainian to the list of language options, to bring jellyfish galaxies to many new audiences!

The forums have been very active, with users showing off some of their most interesting and puzzling finds. Identifying ram-pressure stripping can be challenging using only imaging data, but we’re seeing some very compelling examples being shared by our volunteers!

Behind the scenes, we’re continuing to investigate more clusters to add to the project. Each new sample is a great opportunity to find more jellyfish galaxies, so we’re making use of this momentum, and our volunteers’ keen eyes for ram-pressure stripping features, to hopefully discover many more. With the release of DECALS DR10, we’re also hoping to gain imaging data in totally new regions of the sky, overlapping with other surveys and allowing us to explore ram-pressure stripping in even greater detail. We’ll bring you more news on additional samples as soon as we can!

Thanks for all your help so far, we’re discovering some incredible new galaxies and we’re looking forward to exploring them with you!

Now Available in German and Croatian!

We’re excited to announce that “Fishing for Jellyfish Galaxies” is now available in German and Croatian, expanding our reach and bringing jellyfish galaxies to a new audience! We hope that by adding more languages, we can bring these incredible galaxies to more people around the world.

We’ve now passed half the number of classifications we need to complete the initial sample, and with the classification rate showing no signs of stopping, we’re now working hard behind the scenes to expand on our initial sample and add more datasets to the project. We’re really overwhelmed at the response and our volunteers’ hard work searching for jellyfish!

With many new candidate ram-pressure stripped galaxies being posted each day in the forums, we’re seeing a huge variety of objects, which is really promising for future studies of ram-pressure stripping. These objects are already very rare, so finding “niche” examples, such as those with active galactic nuclei in their centres, or at greater distances from us, or stripping at unusual angles, is even more challenging. By expanding our sample into less well explored combinations of features, we can gain a much richer understanding of the process of ram-pressure stripping and its influence on galaxies in The Universe.

The Search for Jellyfish: One Week In

We’ve had an overwhelming response in the first week of the citizen science project “Fishing for Jellyfish Galaxies”. We have over 600 volunteers helping us look for these spectacular objects, and we’re almost at 40,000 classifications now. That puts us over a quarter of the way through our initial sample already! 5 objects have already been retired as they’ve reached their target number of classifications, and we’re expecting that number to start increasing more rapidly in the coming days. Currently, we’re in the process of finalising additional languages for the project, so we’ll be expanding to wider audiences in the very near future. More info will be coming out very soon on that!

A selection of some incredible candidate jellyfish galaxies found by our volunteers in the forums

Why Jellyfish Galaxies?

Ram-pressure stripping is one of many different kinds of interactions that can convert star-forming galaxies to passive galaxies. It’s important for astronomers to understand the impact of ram-pressure stripping on the general population so we can see how it “evolves” galaxies by stopping their star formation. We’d like to understand more about the relative contribution of ram-pressure stripping compared with, for example, gravitational interactions with the host cluster, or neighbouring galaxies. On top of that, as we find more distant RPS galaxies, we can start to understand how its influence has changed throughout the history of The Universe.

A larger sample of ram-pressure stripped galaxies also gives us an insight into the more unusual cases. Recent studies have found examples of ram-pressure stripping triggering an active galactic nucleus (AGN) by provoking material in the central region of the galaxy to fall onto the supermassive black hole, resulting in an enormous release of energy. The known sample of such cases is very small, but hopefully by finding more jellyfish galaxies, we can learn more about this rare effect.

We’re excited to have already covered so much of our initial sample, and we’re always keeping an eye on the forums to answer your burning questions and see the incredible galaxies you’ve unearthed so far. If you’re enjoying the project, help us spread the word and get more volunteers on board!

Almost 20,000 Galaxies classified so far!

As I’m writing this, only a couple of days after launching, we’re approaching the incredible milestone of 20,000 classifications! That’s enough to have classified every galaxy in the sample at least once. Not only that, but we’re already seeing images being retired, meaning they already have the required total of 10 classifications.

A few stunning examples of jellyfish galaxy candidates found by our volunteers in the forum

In addition to the classifications, we’ve seen a huge amount of activity in the forums, with users showing off the more spectacular examples of potential ram-pressure stripped galaxies they’ve found.

Behind the scenes, we’re working hard to bring more language options to the project, so we can reach audiences in even more parts of the world. A lot of science communication is done primarily in English, so we’re hoping to bring the wonders of Jellyfish galaxies to new audiences. These are just around the corner, so we hope to be able to announce new language options very soon.

“Fishing for Jellyfish Galaxies” Passes 10,000 Classifications!

At the time of writing, we’ve already passed 10,000 classifications thanks to the interest and efforts of the public. We’ve been overwhelmed with the support and are very excited to have reached this milestone in less than 24 hours since the project was first publicised. In the forums, we’ve already seen a lot of discussion and some very strong candidates for galaxies undergoing ram-pressure stripping interactions.

Due to the intense interactions they undergo with the surrounding environment, a ram-pressure stripped galaxy is fantastic for studying the complex interplay between a galaxy and its host cluster. We can learn a lot from the star formation processes going on in the stripped tails, and the halting of star formation in the disc caused by the removal of gas from the galaxy. Each of the new galaxies our dedicated volunteers discover help us see this interaction in a slightly different way, allowing us to build up a picture of the overall process.

Thanks to everyone who has been classifying so far, if you’re enjoying the project, please spread the word and get more people involved! We’re looking forward to sharing and discussing many more of these spectacular objects with you.

“Fishing for Jellyfish Galaxies” – The First Day

It’s been an exciting day as we finally launch this crowd-science project to the public.

“Fishing for Jellyfish Galaxies” has been a long time in the works, inspired by these spectacular but rare galaxies. Thanks to the efforts of everyone on the team, we can recruit the power of the people and hopefully discover many many more jellyfish galaxies in astronomical surveys!

Within less than a day of launching, we’ve already passed 2000 classifications – a huge milestone! We’ve seen a lot of activity in the forums, and have even launched a new forum category for people to post the images of incredible jellyfish galaxies they’ve found in other astronomical surveys, beyond the galaxies in this project!

We’re hoping to keep this blog updated with news and announcements, so follow us as we progress through the project. Most of all, a massive thank you to everyone who has been classifying galaxies so far! Please spread the word and help us explore the mysterious world of these cosmic jellyfish!

The Official Launch of “Fishing for Jellyfish Galaxies” on Zooniverse

In the vast Universe, where we can find millions of spiral and elliptical galaxies, we occasionally find  rare and intriguing peculiar galaxies. One particular case is that of “Jellyfish galaxies”, characterised by long tails of material, which form as the galaxy falls at high speed into a denser environment, such as the plasma surrounding a galaxy cluster. These galaxies are a goldmine to study galaxy evolution as they represent the moment when galaxies start to “die”, losing their gas reservoirs from which they can form new stars. Whilst these galaxies are rare and difficult to find via automated, computational techniques, they are much more easily recognised by the human eye, so we are turning to you for help!

Example image of a jellyfish galaxy from the GASP survey. The white colour reveals the stellar light from a spiral galaxy, while the pink colour highlights the striped material trailing behind the galaxy as it plunges through a dense medium.

We are excited to announce a new project: “Fishing for Jellyfish Galaxies” on the Zooniverse.org citizen science platform, which will allow the public to view and classify galaxies in astronomical images taken by DECaLS, the Dark Energy Camera Legacy Survey, to search for and characterise new jellyfish galaxy candidates. By bringing in the help of the public, we’ll be able to increase the number of known jellyfish galaxies (currently in the hundreds) by searching through thousands of images, maximising our chances of finding these spectacular and elusive objects.

The human eye is a fantastic tool for distinguishing signs of disturbances and trailing material. With your help, we hope to double the known sample, and assemble an extensive and varied catalog of these galaxies to aid our understanding of the complex processes which produce and shape these fascinating objects.

When a galaxy falls into the dense environment of a galaxy cluster, it experiences a drag force which can effectively strip the gas component out of the galaxy, leaving a tail of material trailing behind it. This process of transformation is known as “ram-pressure stripping”, and the spectacular tails and clumps of material can often give the galaxy the striking appearance of a jellyfish. Each new jellyfish galaxy identified provides a snapshot of a key moment of the evolution of that galaxy, in a specific  instant of cosmic time. As we find and observe more and more of them, we can piece together a timeline of the process, from the moment they enter a cluster to the point at which they have become fully stripped of their gas.

Snapshot from the Zooniverse project “Searching for jellyfish galaxies”, which you can join online with a click! www.zooniverse.org/projects/cbellhouse/fishing-for-jellyfish-galaxies

Jellyfish galaxies are still fairly rare and the known sample has been built from individual efforts, but with large surveys of astronomical data available, many of them could already have been observed, and are just waiting to be identified!

Our research collaboration (GASP: https://web.oapd.inaf.it/gasp/) has members from different places around the world, so we’re excited to be offering this zooniverse project in 7 different languages, to open up the opportunity for many more people to get involved and help us find these spectacular galaxies.