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Happy 3rd birthday Radio Galaxy Zoo!

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In 2016, you have all contributed to more than 16 years of continuous classification and our project is now two-thirds of its way to completion and what a year it has been!

The biggest science news coming out of Radio Galaxy Zoo this year will have to be the official publication of the Matorny-Terentev cluster of galaxies, (RGZ-CL J0823.2+0333) –named after two of our super-Zooites who discovered the Giant Wide-Angle Tail galaxy (shown in white contours to the left, Banfield et al 2016).   We have also made great progress across several RadioTalk projects such as the Giants, the Spiral-DRAGNs, the Green DRAGNs and the HyMoRS.    Therefore, we will be providing more detailed updates from the team leaders in the coming weeks so please stay tuned for more exciting Radio Galaxy Zoo science highlights from 2016.

Our science team has also been evolving and this year, we bade farewell to Kyle W. and Chris S. who are pursuing new adventures and we sincerely thank them for all the fish.  We also saw the arrival and departure of Tim F., our ANU outreach student who worked with Julie and we hope that you have enjoyed his blog posts earlier this year.

This year, the RGZ science team welcomes Meg Schwamb from Gemini Observatory (who helped with the Chinese translation of RGZ) and Jean Tate, the first RGZ citizen scientist to become an associate member of the RGZ science team.  Meg will be helping us with the upcoming RGZ follow-up observations using the Gemini telescope.

We also have a new student joining our team and working with Julie in the coming year. Meet James L.,  a PhD Candidate in Science Communication at the Australian National Centre for the Public Awareness of Science. He completed his Bachelor of Science (Hons) in 2015 at the Australian National University with a double major in Astronomy/Astrophysics and Science Communication.  I am sure that you’ll hear more from James himself in the coming year.

Thank you all very much for your support again. We are most grateful for your help thus far. To finish the remaining third of the project, we seek your help in the coming days, months & year to complete this monumental task.

We wish you all a wonderful holiday period and a great upcoming year!

Cheers,

Ivy, Julie & RGZ team

 

 

Discovered galaxy cluster named after two citizen scientists

This post was written as a contribution by Timothy Friel, an undergraduate Australian National University student studying Theoretical Physics and Science Communication. Tim is conducting research into citizen science projects and their social media communication strategies.


Hats off to two of our volunteer participants who have officially been written in the stars.

The Matorny-Terentev Cluster RGZ-CL J0823.2+0333 bears the name of the two citizen scientists who pieced together its structure.

Ivan Terentev and Tim Matorny, two Radio Galaxy Zoo participants from Russia, discovered that a particular radio-source had a line of radio blobs delineating a C-shaped ‘Wide-Angle Tail galaxy’ (WAT). The massive galaxy hosting the super-massive black hole and its associated jets are moving through intergalactic gas, causing the jets to fold back, similar to the way a sky-diver’s hair is shaped by the wind.

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Figure 1: The new discovery: The C-shaped “wide angle tail galaxy” (pink) surrounded by the galaxies of the Matorny-Terentev cluster (white). Julie Banfield, Author provided

This discovery has been published this week in the prestigious scientific journal Monthly Notices of the Royal Astronomical Society, with the paper “Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy” (accessible for free via bit.ly/RGZpaperWAT).

Lead author of the study, Dr Julie Banfield of CAASTRO at The Australian National University (ANU), said that the discovery surprised the astronomers running the program.

“They found something that none of us had even thought would be possible”, said Dr Banfield.

More details of the research team’s response and the next steps for the project can be read in the press release published by CAASTRO (bit.ly/PR14June16).

A huge congratulations must go to the two citizen scientists, Ivan and Tim, for their efforts to work collaboratively to make this discovery. It is great to witness that physical and language barriers have been unable to halt amazing scientific endeavours.

A further thank you must also be noted for the Radio Galaxy Zoo team, in particular the joint project leaders Dr Julie Banfield (ANU) and Dr Ivy Wong (ICRAR at UWA), alongside Dr Anna Kapinska (ICRAR at UWA), Dr Ray Norris (CSIRO/WSU) and all other members of the international project. The team’s continued energy to motivate volunteer participants to develop their own research projects has uncovered the immense potential of citizen science as both a research tool and a method of bringing people together across the globe.

Finally, the Radio Galaxy Zoo team would like to thank the 10,000 volunteers globally who have volunteered to conduct over 1.6 million image classifications over the past two and a half years. The dedication of volunteers to this project has bred a supportive community which has now completed almost 60% of the dataset, a feat unable to be achieved by any single individual.

If you would love to become involved in this international astronomical community, please head to bit.ly/RadioGalaxyZoo1 and begin your journey to uncover the depths of our universe and its wonders, all from the comfort of your own home.


ANU: Australian National University
CAASTRO: Australian Research Council Centre of Excellence for All-Sky Astrophysics
CSIRO: Commonwealth Scientific and Industrial Research Organisation
ICRAR: International Centre for Radio Astronomy Research
UWA: University of Western Australia

Exclusive interview with our recent Citizen Science co-authors

This post was written as a contribution by Timothy Friel, an undergraduate Australian National University student studying Theoretical Physics and Science Communication. Tim is conducting research into citizen science projects and their social media communication strategies.


Meet two of our fantastic Zooniverse members who have been recognised as co-authors for a RGZ submitted paper.

In March 2016, the Radio Galaxy Zoo (RGZ) team submitted a paper which is co-authored by two of our SuperRGZooites. Thanks to the help of citizens around the world, over 1.6 million classifications have been made. However, a very special thanks must go to two citizens who have been greatly involved in our most recent submitted paper.

19MAR2016

Meet Ivan Terentev and Tim Matorny, our Citizen Science co-authors.

How did you discover Radio Galaxy Zoo and become involved?

Tim: I had a passion for research and to be involved with generating new knowledge. So I began to look and met [the world of] citizen science and tried many different projects. I was already familiar with the Zooniverse, when I got email about new project – RGZ.

Ivan: I became involved in RGZ from its beginning, more or less, in December 2013, and at that time I was part of the Zooniverse for two years. I was mostly contributing to the Planet Hunters project back then, but occasionally I switched to different projects just to look for what they have to offer. And it was during one of these “Let’s try something different” moments that I discovered RGZ through the announcement post in the Galaxy Zoo blog.

What parts kept you interested and motivated to stay a part of this project?

Tim: The team of scientists and their active participation is an important part. Their blog posts, comments and links have helped me to learn about the project and my involvement with the goals.
Looking for host radio lobes which are separated by a 10′ [minutes] or looking at the behaviour of jets in galaxies clusters is really exciting for me. I like that RGZ covers a wide range of data: radio, optics, IR, X-ray.

Ivan: If we are talking specifically about RGZ, it would be the RGZ Talk community and the fact that RGZ Science team is eager to communicate with simple volunteers and involve them in the research process. But a large portion of my motivation [for RGZ] is the same as for the rest of the Zooniverse projects. You see, I am sci-fi fan and it made me interested in space exploration. I like to watch documentaries about the astronomers, their work and all the amazing stuff in the universe around us and through the Zooniverse I can actually be involved in the process of science and help to shape the future, even if it just by a very tiny fraction. I never thought that something like this would be possible before I discovered Zooniverse.

How do you feel about being a co-author of a scientific research paper?

Tim: I am still amazed and feel more motivated to look for stunning new radio galaxies.

Ivan: This isn’t the first time actually, I am also a co-author for three papers from the Planet Hunters, BUT it is always awesome, like every single time! Although, I keep my head cool over that since most of the work was done by the professional scientists. A huge thanks to them for the acknowledgment of my small contribution in the form of inviting me to be a co-author in their paper. With this RGZ paper, I got a chance to see the whole process of science starting from the simple question “What is that?” and then people trying to figure out what is going on, schedule observations, discussing things and I have been a part of it! All the way through the process, ending with the actual published science article. It was an amazing experience!


Without the contributions made by our volunteers all over the world, we would not have been so successful in our endeavours.

However, we have only reached 57% of our classification target. Head to www.bit.ly/RadioGalaxyZoo1 to become involved and you could be co-authoring another great discovery with us!

Radio Galaxy Zoo Highlights from 2015

Happy New Year!  I hope everyone had a relaxing break. Radio Galaxy Zoo had a couple of highlights over the last year with new discoveries that will be out later this year.  Well done everyone!

We now have over 1.45 million classifications and are at 48% complete.

Here are a few of our notable highlights:
Papers
Surprises
  • progress on the giant WAT is continuing to bring up more interesting information including our JVLA data – potentially 3 additional papers;
  • we obtained 4 hours to obtain a spectrum for four of our green DRAGN with the observations scheduled for March 2016; and
  • with all your work, RGZ has discovered over 100 new giant radio galaxies!
We are continuing to work away on the data that keeps coming in.  Keep your eye out for our next few projects:
  • matching of RGZ classifications to SDSS;
  • merging Galaxy Zoo data with Radio Galaxy Zoo data;
  • our observations with the JVLA on the hybrid radio sample is complete with 60 hours of observing time; and
  • we are working with the International Astronomical Union (IAU) to get the RGZ name official.
A big welcome to our new team members:
  • Martin Hardcastle (Hertfordshire)
  • Sarah White (ICRAR/Curtin)
  • Francesco de Gasperin (Leiden)
All of this could not have been accomplished without all of you – big THANK YOU! Looking forward to a great 2016!
Julie, Ivy and the RGZ team

Happy 2nd Birthday, Radio Galaxy Zoo!

blog_dec15_fig

Happy 2nd birthday to Radio Galaxy Zoo!

On Radio Galaxy Zoo’s 2nd birthday, we wish to thank you all for achieving more than 1.42 million classifications (~57.2 years of work)!  That is an extra 20 years of classifications just in the last year.  We are nearly at the halfway mark now so we are cheering you all on for the great effort and dedication that many of you have shown.

So what has the science team done in the last year with your classifications?  Our first refereed paper has  been published.

Anna Kapinska’s HyMoRS paper has been submitted for publication and we have another 3  papers on the sidelines in preparation and awaiting submission in the next few months.

And we have also submitted several proposals to conduct follow-up observations of the many interesting systems that you all have found!

Thank you all very much for your support again. We are most grateful for your help thus far. However, we still have more than half of our sample to classify. So we are seeking your help in the coming days, months & year to complete this monumental task.

We wish you all a wonderful holiday period and a great upcoming year!

Cheers,

Ivy, Julie & RGZ team

Radio Galaxy Zoo: conferencing in Italy (Day 4)

Final day of the conference. Still pro-pasta, but may have hit my personal limit on gelato and/or red wine.

We had only a half day for the final day of the Bologna workshop on extragalactic radio surveys. After a tasty conference dinner at the historic Palazzo Re Enzo, we devoted the morning to AGN physics. This is the counterpart to the sessions we had on star formation in galaxies on Monday; almost all continuum radio emission that we detect in individual galaxies is either due to a thermal component from star formation or synchrotron and free-free emission that’s produced in some way by the central supermassive black hole, known as an active galactic nucleus (AGN).

Leith Godfrey (ASTRON) gave a really neat talk on “remnant” radio galaxies, which refers to galaxies that still have active radio emission from the heated plasma in distant lobes, but for which we don’t see the jet because the black has shut down its active phase some time ago (in our observed frame). We can identify these remnants both via morphology (big radio lobes with no jet or core) and through their radio spectra – energy losses from the particles cause a characteristic curved shape which you see if you plot frequency vs. radio flux density. Leith has been doing statistical studies of remnants, finding that less than 1% of bright radio sources are in a dying phase. This is interesting since the number of sources we observe constrains the timescales on which radio galaxies die. It also points toward certain physical properties – there are strong adiabatic losses after the jet switches off, but the lobes seem to remain very high-pressured compared to their environments right up until the end of their lives.

Marisa Brienza (ASTRON) gave the talk immediately following on a new remnant, named BLOB1, that she and her team just detected with LOFAR. LOFAR, a low-frequency array located in the Netherlands and other European countries, is just ramping up full operations, but will be a hugely powerful instrument for increasing the size of these samples over the next decade.

Example of a new radio remnant, named BLOB1, detected with the LOFAR telescope at 137 MHz. From Brienza et al. (2015).

Example of a new radio remnant, named BLOB1, detected with the LOFAR telescope at 137 MHz. From Brienza et al. (2015).

After several more talks, Mike Garrett (ASTRON/Leiden) gave some closing remarks on the conference, including some summaries of what had been discussed and where he thought the future of extragalactic radio sources was going. I was really stoked that RGZ was one of the first results that he specifically cited as being important; Mike mentioned both citizen science and new distributed software routines as being crucial for dealing with the potentially billions of new celestial sources that telescopes will detect in the next decade. The role of citizen scientists in radio astronomy may change – I’ve talked to scientists at this conference about someday doing tasks other than morphology identification, for example – and we’ll definitely have to increase the interplay between the citizen science datasets and machine learning algorithms to maximize our survey results. But, as Mike said on his final slide, the present state of radio surveys is very bright indeed, and we have every reason to think that the best is yet to come.

It’s been a fantastic workshop, and I’m grateful to the conference organizers for accepting my talk and offering financial assistance, the American Astronomical Society for covering my travel costs, and the NSF for partially supporting my work on RGZ at the University of Minnesota. Looking forward to a day or so of sightseeing this weekend, but I’m inspired to get back to work next week and continue being part of such a vibrant scientific community.

Radio Galaxy Zoo: conferencing in Italy (Day 3)

75% done with the conference. Still not sick of pasta yet.

Day 3 of the Bologna workshop on extragalactic radio surveys started with a session on the most massive structures in the Universe: galaxy clusters. These collections of galaxies within massive dark matter haloes show up in radio surveys in several different ways: these include radio haloes, which are diffuse large-scale emission regions not associated with a particular galaxy; radio relics, which are similar features but found at the edge of clusters and likely driven by shock waves, and individual radio galaxies found within and nearby these clusters. Reinout van Weeren (Harvard/CfA) gave a really interesting talk on measuring the spectral index in radio relics; this means measurements of the ratio of the radio luminosity at different frequencies, similar to the way color is defined at optical wavelengths. Changes in the radio spectral index trace variations in turbulence in the intracluster medium, or possibly changes in magnetic fields; the fact that radio relics in many clusters have very different spectral index maps is a puzzle that makes it difficult to explain them with a single model.

A spectral index map of the

A spectral index map of the “Toothbrush Relic” (1RXS J0603.3+4214) between frequencies of 610–325 MHz, taken with the Giant Metrewave Radio Telescope in India. From van Weeren et al. (2012).

We also had the second poster session of the conference, including another Radio Galaxy Zoo result! The poster was led by RGZ science team member Minnie Mao (Joint Institute for VLBI in Europe), titled “Here Be Spiral DRAGNs”. Jean Tate, Minnie Mao, and several RGZ volunteers and science team members have been using RGZ to search for radio-loud AGN whose host galaxy is a spiral.* The acronym “DRAGN” stands for “double-lobed radio source associated with galactic nuclei”. These are extremely rare objects – the number of confirmed spiral DRAGNs discovered so far can be counted on your fingers – but really interesting. The standard physical model for how double-lobed, powerful radio sources are generated are triggered by mergers between galaxies and ultimately their black holes. In the process, a major merger disrupts and destroys the disk of the galaxy, resulting in an elliptical – this theory would predict that we see double radio AGN exclusively in massive ellipticals. That’s mostly true, but the existence of exceptions are fascinating and force astronomers to consider alternatives or extensions to the merger driven hypothesis. Minnie and Jean are going through a sample preliminarily assembled in RGZ to try and identify more candidates like these.

Minnie Mao (left) loves explaining her research on spiral DRAGNs from Radio Galaxy Zoo.

Minnie Mao (left) loves explaining her research on spiral DRAGNs from Radio Galaxy Zoo.

One more day to go!

*Changed wording on 24 October 2015 to emphasize the roles played by both volunteers and the science team.

Radio Galaxy Zoo: conferencing in Italy (Day 2)

Yesterday was the second day of the workshop in Bologna on extragalactic radio surveys, where I’m attending and gave a talk on Radio Galaxy Zoo. We had three major blocks of talks yesterday: one on galaxy evolution, one on cosmology, and the final one on exploiting synergies between radio telescopes.

Galaxy evolution is a big topic, and one that drives a lot of the science behind both Galaxy Zoo and Radio Galaxy Zoo. Several of the talks really highlighted the importance of having multiwavelength data, in addition to what we learn from the radio (this is one of our main goals identifying the optical counterpart in our project). A couple of the most famous deep fields which have been studied in radio were discussed, including the VLA-COSMOS study, GOODS-North, and the Hubble Deep Field.

Poster showing the field and some zoomed-in sources from the VLA-COSMOS project. http://www.mpia.de/COSMOS/

Poster showing the entire field and some zoomed-in radio sources from the VLA-COSMOS project. http://www.mpia.de/COSMOS/

Data from new telescopes, like the low-frequency LOFAR, are yielding some exciting results. One interesting result was the fact that lower-mass galaxies more commonly hosted active galactic nuclei (AGN) seen in the radio in the early Universe, at redshifts of 1 < z < 2. Galaxies with higher masses, however, had about the same fraction of radio-loud AGN at this time. It’s interpreted as being the result of more galaxies accreting matter in what’s known as “cold” or “radiative mode”, thanks to the increase in the supply of cold gas available to galaxies at earlier times (Wendy Williams, U. Hertfordshire).

Cosmology is probably being a bit underrepresented at this conference, since we only had three talks in this session. A lot of the focus was on how detecting very large samples of galaxies (both in radio continuum, like the FIRST and ATLAS surveys in RGZ data, as well as looking at spectral lines like the 21-cm hydrogen line) constrain our cosmological models. Different parameters for both dark energy and dark matter make specific predictions for how populations of galaxies evolve, including their numbers, distributions of sizes and masses, and geometrical arrangement. You can also test cosmology through gravitational lensing at radio wavelengths. It’s promising, but very challenging compared to how it’s done in optical wavelengths due to difficulties in fitting shapes in the raw visibility data (Prina Patel, U. Western Cape).

One of the talks I found really interesting (and new to me) was by Emma Storm, from GRAPPA/U. Amsterdam. She gave a great presentation on how radio observations explore the nature of dark matter. While we don’t know a huge amount about the nature of the dark matter particle, one prominent theory predicts that when they collide, the particles annihilate and produce other particles in the Standard Model that we can directly observe (like pions and gamma rays). If that’s so, then these annihilations would also produce charged particles like electrons and positrons; when those particles are accelerated in magnetic fields, they emit synchrotron radiation, which we detect in the radio. So by looking for radio emission in objects that we expect to be dominated by dark matter (like galaxy clusters), scientists can constrain the parameters of their dark matter models, particularly things like the cross-section. The signal this would produce is expected to be diffuse and weak, though; Emma’s work doesn’t detect radio emission in many clusters, but places important upper limits on the amount that could be there within the detection limits.

Limits on dark matter annihilation cross sections as a function of the particle's mass. Each curve is an upper limit based on radio observations of a galaxy cluster (from Storm et al. 2013).

Limits on dark matter annihilation cross sections as a function of the particle’s mass. Each curve is an upper limit based on radio observations of a galaxy cluster (from Storm et al. 2013).

The last session of the day dealt with synergy and commensality. I normally hate things that sound like business-speak buzzwords, but in this case it is really important – we have a number of new radio telescopes coming online now or in the next several years, such as ALMA in Chile, LOFAR in Europe, and the Square Kilometer Array in Australia and South Africa. It’s quite important to plan the capabilities and designs of each so that we don’t repeat work unnecessarily, maximize the scientific output, and try to make the data and results available to as many people as possible.

Halfway over already! You can also follow what some of the other people have been discussing at the conference at the hashtag #radsurveys15.

Radio Galaxy Zoo: conferencing in Italy (Day 1)

One of the best things about being a scientist is the opportunity to attend conferences – you get to visit a new place, meet your colleagues in person, learn about what they’ve been doing, and get a chance to share your exciting research with them. I’m lucky (through the assistance of the American Astronomical Society, the Italian National Institute for Astrophysics, and the University of Minnesota) to participate in a conference this week on the future of extragalactic radio surveys in Bologna, Italy. I’m getting my first chance to share results from Radio Galaxy Zoo and to learn about other, new results in the area of extragalactic radio science!

The conference is four days, from Tuesday – Friday; I’m going to try to make a blog post each day. I’m going to try give a quick overview of all talks/posters on the day, as well as more details on talks which I thought were particularly interesting. I know I won’t do justice to many of the interesting research topics being presented, but I won’t have time to give every topic the breadth they deserve.

The first day of the workshop started with several talks covering current and upcoming surveys in radio astronomy. These include radio telescopes in the Northern Hemisphere. The two main telescopes discussed were the Very Large Array (VLA) in New Mexico, USA, which will run surveys like VLITE (a low frequency survey which will run constantly on the telescope in parallel with other observations), and VLASS, a new all-sky survey with many similarities to the current FIRST data in Radio Galaxy Zoo. LOFAR is a low-wavelength radio telescope with stations centered around Europe; it will open up similar resources, but at significantly lower frequencies than the VLA and thus probing different physical phenomena. In the Southern Hemisphere, the EMU survey in Australia and the MIGHTEE survey in South Africa will carry out similar responsibilities.

I gave a talk at the end of this session on Radio Galaxy Zoo, covering our first accepted paper and some of our early science results. If you’re interested, I’ve put my talk online here.

Example slide from K. Willett's talk on Radio Galaxy Zoo at the Bologna workshop.

Example slide from Kyle Willett’s talk on Radio Galaxy Zoo at the Bologna workshop.

The afternoon had two sessions on science: one on radio continuum and star formation, and one on radio observations of the transient universe.

I think after the first day that I’m filled with a great sense of optimism about radio astronomy. We’ve got a fantastic new telescope being built in the next several years: the Square Kilometer Array. It’ll be the largest telescope ever built, addressing a huge number of scientific questions. We’re currently in the stage of building prototype telescopes, but those telescopes are already producing useful science – some of which I learned of today. We have a reasonable understanding about how things like magnetic fields affect both the formation and evolution of galaxies. Radio observations have a unique way of detecting and leveraging these detections; through polarization of the radio signal, we can measure the magnetic field and directly probe (through its signal) the interactions with matter between its source and our telescopes. New phenomena like fast radio bursts are, I think, a really neat way of measuring both the amount and distribution of matter in the Universe – this has implications for everything from star formation to cosmology.

Really excited for the rest of the week (including more Radio Galaxy Zoo results) – will post again tomorrow!

First Radio Galaxy Zoo paper has been accepted!

The first Radio Galaxy Zoo paper has been accepted by the Monthly Notices of the Royal Astronomical Society (MNRAS) and is available today on astro-ph.  The paper entitled Radio Galaxy Zoo: host galaxies and radio morphologies derived from visual inspection outlines the project and provides the first look into some of the science that has come from Radio Galaxy Zoo.

An example of a galaxy where visual identification of the radio components is necessary. Automated algorithms would have classified the non-core emission as independent sources, whereas RGZ volunteers (in agreement with the science team) found all five radio emission components in the upper half of the image to be related to the same source.

Fig. 1. An example of a galaxy where visual identification of the radio components is necessary. the automated algorithms would have classified the non-core emission as independent sources, whereas RGZ volunteers (in agreement with the science team) find all five radio emission components in the upper half of the image to be related to the same source.

As mentioned in our previous article about the paper, we find that the RGZ citizen scientists are as effective as the RGZ science team in identifying the radio sources and the host galaxies.  The project now has over 7500 citizen scientists and their contributions are individually acknowledged at http://rgzauthors.galaxyzoo.org

(a) WISE colour-colour diagram showing approximately 100,000 WISE all-sky sources (colourmap), 4614 RGZ sources (black contours), and powerful radio galaxies (green points).  (b) WISE colour-colour diagram dhowing the locations of various classes of astrophysical objects from Wright et al. (2010).

Fig. 2. (a) WISE colour-colour diagram showing approximately 100,000 WISE all-sky sources (colourmap), 4614 RGZ sources (black contours), and powerful radio galaxies (green points). (b) WISE colour-colour diagram showing the locations of various classes of astrophysical objects from Wright et al. (2010).

Using the classifications of the WISE infrared host galaxies, we find that the majority of the host galaxies are located in the WISE colour space consisting of elliptical galaxies, quasi-stellar objects (QSOs), and luminous infrared radio galaxies (LIRGs) – see Fig. 2.  Upon closer examination of the RGZ objects that are identified as elliptical galaxies in the WISE W1-W2< 0.5 colour space we note that our current sample shows a possible large population of star-forming galaxies and/or ellipticals with enhanced dust – see Fig. 3.

Distribution of (W2 - W3) infrared colours for objects near the region identified as elliptical galaxies (W1 - W2) < 0.5.  Solid and dashed vertical lines show the  median colours of the all-sky and RGZ sources.  While sources randomly selected from the WISE all-sky sample peak near (W2 - W3) = 0, our current RGZ sample shows a large population with significantly redder colours - possibly from star-forming galaxies and/or ellipticals with enhanced dust.

Fig. 3. Distribution of (W2 – W3) infrared colours for objects near the region identified as elliptical galaxies (W1 – W2) < 0.5. Solid and dashed vertical lines show the median colours of the all-sky and RGZ sources. While sources randomly selected from the WISE all-sky sample peak near (W2 – W3) = 0, our current RGZ sample shows a large population with significantly redder colours – possibly from star-forming galaxies and/or ellipticals with enhanced dust.

We still have a lot of radio sources in our project that need classification and we hope to continue the great work from all our citizen scientists and science team.  Don’t forget to head over to Radio Talk for interesting discussions on objects or some of the science in general.
Thank you once again for your hard work and support throughout the first years of Radio Galaxy Zoo!