Good Things come at the same time
AAS meeting update!
The last 24 hours have been good for Zoo team member Bill Keel (@ngc3314) is based at the University of Alabama. Not only did his University football team win some sort of championship (they all look the same to Europeans) last night, but the Hubble Space Telescope observed the final Voorwerpje in our approved programme! That means Bill was probably glued to the TV and downloading and reducing the data at the same time!
He’ll add the reduced image to his poster at the AAS meeting, so if you want to see the image, come join us at the poster tomorrow! He may also blog it some time later, but for the FIRST look, you’ll have to come to the poster! There may be chocolates too….
The poster is: 339.47. HST Imaging of Giant Ionized Clouds Around Fading AGN, up all of Wednesday from 9-6.
The Galaxy Zoo Team goes to Long Beach CA
It’s January and that means that astronomers from all over the world flock to the American Astronomical Society‘s annual winter meeting (Jan 6-10 2013). This year, the 221st meeting, is in Long Beach CA. Quite a few of the team members and collaborators are going to the meeting and we’ll keep you posted on the exciting results that we’ll be presenting here on the blog and via our twitter account at @galaxyzoo.
The following talks by the team will be happening:
I’ll (@kevinschawinski) be talking about how blue galaxies turn into red ones (I needed all the blue ellipticals and red spirals you all found!) and how the two processes are completely independent. The talk is based on a paper in progress that I’m hoping to get ready for submission soon.
Kyle Willett (@kwwillett) will present an update on the reduction and analysis of the Galaxy Zoo 2 data. How do we turn your clicks into galaxy classification? This is the talk that will explain it!
Brooke Simmons (@vrooje) is going to update us on how bulgeless galaxies spotted by you! managed to grow enormous 10 millions solar mass black holes at their centers entirely through `gentle’ or `secular’ processes. No major mergers here!
Sugata Kaviraj will talk about the formation of early-type galaxies in the first half of cosmic time and discuss how your clicks from the ongoing Hubble Zoo might help uncover their secrets. And about how to get short term loans when you’re a student of the universe.
Finally, Bill Keel (@ngc3314) will present a poster with the latest analysis of the Hubble data of the Voorwerpjes, the light echoes of dying black holes.
Our friends from the Planethunters team are also going and may have some exciting news up their sleeve as well!
Observing Time for Galaxy Zoo
It’s Christmas come early at Galaxy Zoo, with a healthy dose of everything that an astronomer would want under the tree – observing time.
The Gemini South dome in suitably picturesque setting.
We didn’t get everything we asked the telescope allocation committees for, but we did get plenty to keep us busy well into the New Year. 2013 will see the following telescopes turned to Galaxy Zoo targets :
Gemini South: This 8m telescope in Chile (pictured above) will be observing bulgeless galaxies thanks to Brooke Simmons and her friends at Yale (especially Ezequiel Treister, now at Concepción in Chile). This is a program to look at the galaxies that were included in our first bulgeless paper, using deep, high-resolution spectroscopy to examine their stellar populations. For some objects where the AGN signal comes to us unobscured by dust and gas (but buried in a bright galaxy that made it hard to see in the SDSS spectra), we hope to also determine black hole masses with these deeper, finer spectra.
WIYN at Kitt Peak: This 3.5m telescope has recently been outfitted with a brand new imaging camera. As long as it keeps working the way it has been in tests, we can use it for 6 nights to examine whether our sample of bulgeless galaxies ever had minor mergers. Bulgeless galaxies are important because they’re supposed to be guaranteed merger-free so deep imaging of this kind helps us to confirm that that’s true by looking for any remnants of ripped-apart galaxies.
Bolshoi Teleskop Alt-azimutalnyi: This 6m telescope is important in astronomical history – it was once the largest in the world. It will be observing the Voorwerpjes as part of our increasing desire to understand these enigmatic objects – more on which is coming over the Christmas period, with any luck.
Shane Telescope at Lick: We’ve been awarded a second run on this telescope to look for ionized gas in the companion galaxies to those with active galactic nuclei – a sort of large scale Voorwerpje hunt.
There will be much more about all of these as the data starts to arrive, but we wanted to make sure that you know there were presents under the tree. We’re looking forward to unwrapping them immensely!
*Note: this post has been updated to more accurately reflect reality.
600 Most-Galaxified Words
When we launched the new Galaxy Zoo in September we also launched our ‘galaxify‘ tool, which allows you to write in an alphabet of Galaxy Zoo galaxies. Since that time you have created 320,000 messages, all written in galaxies! 18,468 contained the word ‘love’ and only 218 contain ‘hate’. 302 contained ‘marry me’ (5,853 contain swear words). Here’s the top 600 words so far, in one giant green word ball:
Go write your own message at http://writing.galaxyzoo.org and don’t forget to check out the Zooniverse Advent Calendar for more fun items like this one in December.
Hangout with Galaxy Zoo: Science Chat Later Today
Later on today we’ll be holding a Google+ Hangout with a bunch of the Galaxy Zoo science team. We’ll be broadcasting this live at 3:30pm GMT (9:30am CST, 10:30am EST) and you’ll be able to see the video feed right here on the blog.
If you have any questions about the science behind Galaxy Zoo, short term loans UK and how to get them, or anything you’ve always wanted to ask the science team behind the project, please post them here as comments or contact us on Twitter @galaxyzoo.
We look forward to chatting later on and answering your questions.
Space Lasers and the Cosmic Martini: Removing Data Artifacts
As long as there are big data surveys, there will be data artifacts. Our corner of Astronomy is no exception: although the vast majority of images in SDSS and CANDELS are of high quality and therefore of high scientific value, poor quality images do still exist. The Galaxy Zoo team has worked hard to remove as many as possible from both samples so most “bad” images never even make it into the database, but this process is imperfect because computers have trouble identifying every kind of artifact (for some of the same reasons they have trouble identifying different galaxy types).
Of course, as we’ve seen time and again, Galaxy Zoo users have no problem whatsoever spotting the things the computers miss:
Not a Green Pea unless the universe is Tomato Soup.
The thread on Talk where this image was discussed pointed out that this was in the “Cosmic Scarf” of SDSS, where most of the fields have poor image quality:
Now, most of the fields in the zoomed-out image above were removed from the database and will never be shown on the website, but even the parts that look okay in the zoomed-out image don’t look so great when you zoom in. SDSS combines a number of its quality flags to give each field a “score” from 0 (terrible) to 1 (excellent) to assess its quality, but it’s not always that reliable. For example, although fields with scores larger than 0.6 are generally considered good, this field has a score of 0.77 but is clearly not quite right:
And this field has a much lower score of 0.37 but the images are classifiable:
So any choice we made at the beginning based just on the computer evaluations was going to leave some artifacts in, and we chose to err on the side of showing as many classifiable images as possible (increasing the number of artifacts kept in).
The good news is that Galaxy Zoo has always been adaptable, improving with input from all its participants. Now that this field has been flagged, the science team is working on a two-pronged approach: first, removing the entire “cosmic scarf” should immediately help prevent the majority of these big groups of artifacts from being loaded onto the server. Second, we’re working on finding a better method of removing those artifacts that remain, using your classifications and also your hashtags on Talk. (We’re also working on using this to help make the computers better at spotting artifacts in the future.)
So keep clicking, and remember, even your “artifact” clicks are useful.
AGN in Bulgeless Galaxies: Paper Accepted
Longtime readers of the Galaxy Zoo blog will be familiar with the peer review process from the many posts here describing it. The time elapsed between a paper’s submission and its acceptance (if it is accepted) can be long or short, and papers from the Zoo have sampled the whole spectrum.
The process with our paper on supermassive black holes growing in bulgeless galaxies took about 4 months: we submitted the paper in July, received comments and suggestions from the anonymous referee in August, then modified the paper based on the referee’s report and re-submitted it in October. This week, the paper was accepted by MNRAS.
The initial report from the referee was extremely thorough and constructive, and incorporating his/her comments helped to significantly improve the paper. The referee pointed out, for example, that although the paper emphasized the lack of significant mergers in the evolutionary histories of the sample, the bulgeless nature of the sample excludes not just mergers but any violent evolutionary process that can disrupt a disk to the point where it transfers a significant fraction of its stars from a disk into a bulge or pseudobulge. That was certainly a fair point, so we changed our discussion to include further consideration of the implications of those evolutionary processes being excluded.
And we made some other changes, too, including expanded discussion of why our results differ from some other studies and additional description of how we might be affected by dust in these galaxies (and why we think we aren’t). There were also some very interesting questions that we couldn’t really answer within the scope of this paper, but that we had asked ourselves too and that have already formed the basis for additional projects now underway. Overall, this was a classic example of what the peer review process was meant to be.
The accepted version of the paper will soon be available on the arXiv for anyone to download. In the spirit of openness, I had hoped to include the referee’s report and our response in the additional materials on the arXiv, but the referee did not give permission to do so. That’s fine — it’s anonymous and it’s perfectly acceptable if the referee prefers the exact contents of the report to be private as well. Hopefully he/she approves of my summary!
Note: as soon as it’s published, the paper will also be added to the Zooniverse Publications page, which coincidentally happens to have been released today as the first day of the Zooniverse Advent calendar. Have a look — Galaxy Zoo’s contributions are impressive and we’re joined by many, many others.
Overlaps and backlights and silhouettes – oh, my!
After a winding path, the first overlap paper from the Galaxy Zoo search has been accepted for publication. The title and abstract pretty much tell the story (the title links to the complete preprint):
Galaxy Zoo: A Catalog of Overlapping Galaxy Pairs for Dust Studies
William C. Keel, Anna Manning, Benne Holwerda, Massimo Mezzoprete, Chris Lintott, Kevin Schawinski, Pamela Gay, and Karen L. Masters
(PASP, likely January 2013 issue)
Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of disks. The sample spans wide ranges of morphology and surface brightness, opening up the possibility of using this technique to address systematic changes in dust extinction or distribution with galaxy type. This sample will form the basis for forthcoming work on the ranges of dust distributions in local disk galaxies, both for their astrophysical implications and as the low-redshift part of a study of the evolution of dust properties. Separate lists and figures show deep overlaps, where the inner regions of the foreground galaxy are backlit, and the relatively small number of previously-known overlapping pairs outside the SDSS DR7 sky coverage.
This was the project that first drew me in to Galaxy Zoo, way back in August of 2007. Zooite’s contributions to this, perhaps the first science project organized on the Forum, exceeded my wildest hopes. As the paper shows, the previously-known set of backlit spiral galaxies in the local Universe contained only about 20, severely limiting what we could learn about the galaxies’ dust content. By the opening of Hubble Zoo, when we froze this particular list for publication, the combined catalog reached nearly 2000. Further use of this catalog is well along – we’ve had several observing runs at Kitt Peak 2.1 and 3.5m telescopes to do more detailed images, and colleague Benne Holwerda is headed to the 4.2m William Herschel Telescope atop the island of La Palma next month for more. With such a large starting sample, we can address questions we couldn’t before. How much variation in dust content and distribution do we see among apparently similar galaxies? How many dwarfish galaxies show the kind of unusual dust concentrations in their outskirts seen in one particular case? Do we see significant dust that is so cold that it eludes even far-infrared detection? On another keyboard, I’m working now to finish a paper on the ultraviolet absorption properties of dust in galaxies, combining a target list of spiral/spiral pairs from the GZ catalog with GALEX satellite data and our ground-based images. Not only is this interesting in knowing how clumpiness of dust affects its absorption properties, but is a key stepping stone toward another project – using backlit galaxies from Hubble Zoo to probe the history of dust in galaxies over cosmic time. We see some at such high redshift that the Hubble data sample light that started out well down toward the ultraviolet, so knowing how to compare that to our place and time is the basic starting point.
To show off the richness of this collection, this two-part figure from the paper shows how we divided them up into broad categories so that subsets useful for different things can be easily retrieved. This is one thing that lets us address different questions – we now have many examples of a broad range of geometry and combinations of galaxy types.
Nearly 600 Zooites contributed candidate pairs (we list the thread participants on the data page for seo services). A few deserve to be singled out. Half65, of course – not only did he find a remarkable fraction of these pairs, but he did a lot of work collecting their SDSS information. You’ll notice he’s a coauthor – fair is fair! Also, c_cld continues to display his remarkable SQL skills – he saved me a lot of time in revision by finding all the redshifts that were new when SDSS DR8 was released. Jean Tate corrected some typos in the data table (how does she do that?), and helped prod me to take the time to organize the pair members’ data more systematically by magnitude.
Regular Forum readers will recall that the first version of this paper was submitted last year. The MNRAS referees liked the analysis, but felt that the extensive catalog itself was better suited to another journal. As a result, we split that paper in two, sending the catalog and its documentation to the Publications of the Astronomical Society of the Pacific, and have been able to expand the analysis of dust distributions, so that paper will wind up even more substantial than we anticipated.
Once again – thank you to all who have taken part, and keep looking in the background as the Zoo takes in more of the sky from more telescopes!
Want to work with the Galaxy Zoo Team?
The Zoo team is once more expanding, this time in the new Black Hole and Galaxy Astrophysics Group at the ETH Zurich Institute for Astronomy in Switzerland!
Your new morning view could include the Alps…
We’re looking for:
A Postdoc
AAS ad: http://jobregister.aas.org/job_view?JobID=43152
The postdoc position is for two plus one year and comes with support for travel, computing, publishing etc. Research will include work with Galaxy Zoo data, especially the new Hubble Zoo data from CANDELS and also include the hunt for the first black holes in the universe.
Two Ph.D Students
AAS ad: http://jobregister.aas.org/job_view?JobID=43155
The Ph.D positions are fully funded for four years and also come with support for all things a student needs. Both thesis ideas are based on Zoo data and ideas. For the Ph.D position, you’ll need a Master’s degree in physics, astronomy, or related field.
Both postdoc and the students can get involved in the Zooniverse and getting more people to engage with science online.
Zurich is usually ranked in the top ten cities in the world in terms of quality of life and ETH is the highest ranked European university in the world. ETH ASTRO has expertise from planet formation to cosmology and is involved in a number of large projects and surveys. Also, there’s unlimited espresso.
The deadline for both is December 7 2012! For further details, please see the AAS ads.
It’s a bat! It’s a dragon! It’s UGC 11185!
It’s a bat! It’s a dragon! It’s a galaxy-sized set of crab claws! It’s a complex abstract design blending elements of the Mandelbrot set with classical Persian carpet design!
Or, none of the above. This is the first-cut overlay of two Hubble images of the voorwerpje-hosting AGN in UGC 11185. As usual, [O III] is in green and Hα in red; neither has yet had the contribution of starlight in the galaxy taken out. The inner set of clouds could, with a little imagination, be seen as the ind of two-sided ionization cone seen around many active galactic nuclei. But the outer cloud, the one that selected this object for our sample by extending more than 10 kiloparsecs from the core – this cloud shows pillars, loops, and gaps. (I’d like to acknowledge here the help of STScI program scientist Linda Dressel, in making suggestions for subtle changes to our pointing strategies to reduce problems from such effects as reflections from that bright star on the edge of this image).
[O III] and H-alpha images of UGC 11185
Later the same day we first saw the Hubble images, we received additional information on UGC 11185. Colleague Alexei Moiseev (who first showed up on the GZ forum when his team was making sophisticated use of the GZ1 database to seek polar rings) has been getting data on some of these objects with the 6-meter telescope (БТА, Большой Телескоп Азимутальный or BTA) of the Russian Academy of Sciences. In the right redshift ranges, they have a Fabry-Perot device which can map the Doppler shifts of a single emission line across the whole galaxy. As supporting data, he also got this multicolor wide-field image, which shows the complicated tidal disturbances in this galaxy pair. The giant loops of stars may indicate that both are partial ring galaxies. UGC 11185 is the upper left one – you can pick out its core the bright star above it, and the glowing gas clouds around the core and to its left.
UGC 11185 from 6m BTA
Alexei also forwarded this image of a familiar field. We’ve been re-examining the faint outer parts of IC 2497 and its companion galaxy, to see what we can learn about the history that pulled gas out where it could be ionized to form Hanny’s Voorwerp. There is a faint tidal tail to the east (left) seen in Hubble images, and now this wider-field and long-exposure BTA image show how far it stretches. Watch this space to see what we can all learn from this.
IC 2497 image from 6m BTA
Galaxy Zoo 