Galaxy Zoo Blog

Public talk - online

Chris — Mon, 30 Jun 2008 03:11:01 +0000

I’m giving a public talk about Galaxy Zoo and citizen science tomorrow (Monday) night. If you happen to be in or near Southern Illinois then you can find details here. Otherwise you can watch online either below or, if that doesn’t work, here. It kicks of at 7pm Central time, which is 1am BST or 12pm GMT. Streaming Video by Ustream.TV

Fourth Paper Submitted: Lots of Blue Ellipticals!

Kevin — Wed, 25 Jun 2008 20:42:35 +0000

Hi all,

The fourth Galaxy Zoo paper has now been submitted for peer review to the Monthly Notices of the Royal Astronomical Society. The paper describes a sample of blue early-type galaxies (ellipticals) found by you guys and compares them to their much more common red counterparts. We’ll make the paper available for download as soon as possible. Since the paper contains some interesting results, we would like to wait until we get the first referee report before making the draft available to the community.

In the meantime, have a look at the footnote on page 1:

Now we have to wait for MNRAS to send the paper to a referee and await her/his report.

In other news, we’ve gotten back the referee report for the second paper (Lintott et al.), which has been very kind and we’re currently discussing the revised version. Hopefully that’ll mean that the second Galaxy Zoo paper will be accepted soon!

Hanny’s Voorwerp is Astronomy Picture of the Day (APOD)

Kevin — Wed, 25 Jun 2008 12:54:36 +0000

Great news, Hanny’s Voorwerp, the mystery blob found by Hanny, has made it to Astronomy Picture of the Day!

http://apod.nasa.gov/apod/ap080625.html

This is a fabulous success for all of us as the Voorwerp continues to intrigue…

Hanny’s Voorwerp gets Slashdotted

Kevin — Mon, 23 Jun 2008 08:52:03 +0000

This is now the second time that Galaxy Zoo got slashdotted. Hooray!

http://science.slashdot.org/science/08/06/22/1757215.shtml

Overlapping galaxies in color and in detail

BillKeel — Sat, 21 Jun 2008 23:02:28 +0000

We’re making progress in working on the Kitt Peak images of overlapping galaxies (encouraged by recently learning that we have 3 more nights this November, so keep those candidates coming in!). Now that various meetings and proposal deadlines are over, there’s some time to show off color composite images and point out some of the things we’re looking at. For most of these galaxies, we took images in two filters - the B band (blue), which lies between the SDSS u and g filters, and the I filter, which used to stand for infrared but nowadays (with the proliferation of genuine infrared imagers at much longer wavelengths) we think of as a red just a bit too deep for our eyes to see. Making a color image takes three filters, not just two. Fortunately, the colors of most galaxies are so well-behaved that we can synthesize the middle filter (green) from the two we have; this is something done pretty often with Hubble images as well. I then pasted the three coors together using a brightness mapping that is logarithmic starting slightly below the sky-brightness level and consistent across the various galaxies - this ends up much like the familiar SDSS color display. But enough of the details - let’s get to the galaxies. One of our highest-priority targets was NGC 3861, a gorgeous partial silhouette of two ringed spirals. It lies in a part of the sky with a deep ultraviolet exposure as part of the GALEX sky survey, so we can further leverage our images to interpret the UV data and measure the dust at wavelengths seldom possible. The basic approach to measuring absorption by dust is to compare the brightness in a region where we see both galaxies with what we expect for the sum of both, based on symmetry and the non-overlapping regions. Here we certainly have enough light to do that in detail in the small overlap region; our limits will come from how clumpy the star-forming regions are in both galaxies. For comparison, this is SDSS object 587742572687917067. Here’s another beauty - the face-on spirals UGC 5769 and 5770 (you might recognize them better by the SDSS number 587742013810343948 ). The bluer spiral is in front of the slightly yellower ringed galaxy, with the outer ring backlighting some of its distant spiral arms. Here’s another spectacular pair, the spectacle increased even as our work is complicated by the bright star almost in front. This is Arp 198 ( SDSS 587742865816944738).The edge-on galaxy is in the background, showing clearly where the dust in the arms of the foreground spiral blocks its light as they cross in front. You’ll notice more speckles caused by cosmic-ray events in the detector than in the previous ones. Normally we take three exposures in each filter so they can e combined to reject any values that are wild from a single image. but sometimes the atmosphere was so much steadier in one of these that we get a better product by just using that one (and either putting up with the cosmic rays or interpolating across them if in an important part of the image). In Arp 198, the atmosphere was unusally steady during one of the blue images, so we went with that one by itself. I’m getting a little wordy, so maybe this is a good time to leave off. As dessert, here are a few more. “Few” out of a lot - at the rate Zoo participants continue to post new candidates even on the temporary forum, within the next week or so the total number of pairs in our working sample should pass 1000!

Classifying Ring Galaxies

Ciaran — Fri, 13 Jun 2008 13:05:31 +0000

My name is Ciaran O’Hare, I’m a sixth form student at The Cherwell School in Oxford and I came to the Oxford University Astrophysics department as part of my work experience for Year 12. I was set a task to complete of the course of the week, to sort through hundreds of e-mails from from the users of Galaxy Zoo about the unusual ring galaxies.

So I catalogued these galaxies and created catagories, and by finding some data about them we were able to make some interesting discoveries.The ring galaxy is a specific type of galaxy that is believed to be the remnant of a head on collision between a large spiral galaxy and smaller galaxy. One of the most famous is the Cartwheel Galaxy. The first and most common catagory that I made is the circular ring galaxy. These have circular rings and nuclei. Around 54% of the galaxies were of this type.

Typical example -

The second catagory is the elliptical ring galaxies, these have elliptical nuclei and most often, elliptical rings aswell. About 24% of the galaxies were of this type.

Typical example -

The third catagory is the multiple ringed galaxy, where the central nucleus is surrounded by several concentric rings. About 14% of the galaxies were of this type.

Typical example -

The final type is the off centred nucleus. Similar to the first two catagories but the nucleus is not at the centre of the galaxy. This was the rarest catagory it was made up of only 6% of all the galaxies.

Typical example -

An interesting galaxy that a number of users sent in was this, which was the most bizarre one I came across.

I also looked at the spectra of all the galaxies and found that the large majority of them generally fell with the redder galaxies, with only 1 in 8 having bluer spectra. Also, by measuring the radius of the ring we were able to find an age of the galaxy by taking the expansion rate from the cartwheel galaxy. And by comparing this age with the spectra it is clear that the bluer the galaxy is, the younger it is.

These results will now be followed up with more research, and I’d like to thank everyone who e-mailed Galaxy Zoo, for helping in finding these elusive galaxies.

C. O’Hare.

Galaxy Zoo Meet-up on Tuesday

Chris — Mon, 09 Jun 2008 09:29:10 +0000

Just a reminder (in the absence of the forum) that there’s a Galaxy Zoo meet-up in London this Tuesday. It’ll follow a lecture I’m giving as part of the Royal Astronomical Society’s Lunchtime Lecture Series at their apartments in Burlington House, Picadilly (look for the Royal Academy of Arts). The lecture begins at 1, although you might want to turn up a bit earlier to make sure you get a seat, and we’ll gather in the courtyard outside the RAS at 2 and then go and find somewhere for a late lunch. Hope to see you all tomorrow. Chris

10 JUNE: RAS LUNCHTIME LECTURE: HUBBLE, BUBBLE, TOIL AND TROUBLE: A BRIEF HISTORY OF THE MOST FAMOUS TELESCOPE EVER MADE: BURLINGTON HOUSE, LONDON

Dr Chris Lintott, postdoctoral researcher at the University of Oxford, STFC Science and Society Fellow and co-presenter of the BBC ‘Sky at Night’ will tell the story of the NASA / ESA Hubble Space Telescope (HST), in orbit since 1990. This autumn, astronauts aboard the space shuttle Atlantis will carry out one of the most difficult repairs in history, with the aim of restoring the HST to full working order. Dr Lintott’s lecture will tell the HST story, and look forward to the discoveries still to be made.

The lunchtime lectures are open to everyone and take place in the newly-refurbished Burlington House, the headquarters of the RAS off Piccadilly in central London. The lectures take place at 1pm on the first Tuesday of each month from September to June and the audience can take their seats from 12.45.

The biggest astronomical collaboration in history… just how big?

Jordan — Tue, 03 Jun 2008 16:42:58 +0000

Chris and I are at the AAS meeting in St. Louis. Chris has been keeping up with the meeting on his blog, and we’ve both given talks about Galaxy Zoo. Everyone here is really excited about what we’ve been able to do with Galaxy Zoo - great job, everyone!

Last night, Chris and I held a Galaxy Zoo planning meeting while watching a St. Louis Cardinals baseball game. Here is a beautiful photo of where we were - Busch Stadium in St. Louis (click for a larger version):

Photo from Flicker user pdsphil

Here is a beautiful photo of Busch Stadium 3.2 times over:

Why is that significant?

We suddenly realized, looking up at the stadium, that this is how large Galaxy Zoo is.

The stadium holds about 45,000 people. At last count, Galaxy Zoo had 141,960 volunteers. Here are some other things that we are bigger than:

The entire nation of St. Vincent and the Grenadines
Chris’s hometown, twice over
The entire student population of the Universities of Michigan, Illinois, and Texas, combined
The Italian Army
…and 30 American Astronomical Societies.

More suggestions?

Galaxy Zoo Forum downtime

Edd — Mon, 02 Jun 2008 10:41:21 +0000

If you’re a regular user of the forum at http://www.galaxyzooforum.org/ you’ll notice that it’s currently offline. There’s been a sizeable server outage which has affected it (along with many other websites), and we hope it will be back up soon - but this outage is out of our control. We were actually already planning to transfer it to a new server anyway, and we were hoping to do this on Tuesday, although this downtime may unfortunately get in the way of our plans. If the forum does come back up in time, we may take it down for Tuesday in order to make this transfer, but it should be back up shortly after that. Please bear with us until we can get everything back up and running properly!

Update: Forum is still down unfortunately, but the support staff at the hosting site are working hard to bring it back up. It looks like the transfer will be delayed - and hopefully we’ll be able to give some warning of any resulting downtime from that.

Update 2: (Wednesday morning) Unfortunately there’s been hardware issues as the support technicians tried to bring the server back up. They’re still working on bringing it back up - no estimate for when this will take place I’m afraid.

Update 3: (Thursday morning) We’re in the process of trying to reinstall the forum framework and content back on the original server. A temporary forum is in place. It is not organised in the same way and has a different theme to emphasise this fact, and no posts there will be retained (except maybe in rare cases).

Update 4: (Wednesday morning - 11th June) The disk holding the forum is with a data recovery team, but unfortunately they won’t be able to get anything off for approximately another week at the earliest.

What’s an Astronomer’s favourite Birthday Gift?

Kevin — Fri, 30 May 2008 12:52:32 +0000

As you can see, we woke up this morning, to find that the Space Telescope Science Institute – the organisation running the world’s most famous telescope, Hubble — have sent out their approval and denial letters for the next cycle of observations with the Telescope. Our proposal for observing the Voorwerp (led by Principal Investigator Bill Keel) was approved for 7 orbits. Getting time on HST is hard at the best of times, and this time round was particularly difficult. Hubble is currently waiting for a visit from astronauts to carry out a desperately needed set of repairs and upgrades, and every astronomer in the world wanted to be first in the queue once it’s back on top form. To give you an idea, more than 20,000 orbits were requested when there were only 3,500 of them to go round - and 7 of them now belong to Galaxy Zoo.

So when will you see a gorgeous Hubble image of the Voorwerp? Not for a while yet. First, the Space Shuttle has to successfully complete its final service mission to repair the Hubble and install new instruments. This is currently scheduled for October 8, 2008. After all the repairs are done and the spacecraft has been checked out thoroughly, we then have to wait for the Voorwerp to actually be visible on the sky for Hubble. All this will take at least several months more. And of course once the data is taken, we then have to reduce it first to produce a picture. Still, it will be a wonderful opportunity for us to learn more about what the Voorwerp is.

By coincidence, today’s the birthday of the Voorwerp’s discover. Happy birthday, Hanny - and enjoy your present from the Space Telescope Science Institute.