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Friday, March 26, 2010

Monday, October 20, 2008

Galaxy Clusters Discovered with the SPT!

We are very excited to announce the South Pole Telescope's first major scientific results: detection of four galaxy clusters, three of which are new discoveries! We've been working hard over the last couple of months to analyze the data from the 2007 and 2008 observing seasons, and these first results are just the tip of the iceberg. On October 10th, we submitted a paper documenting the new discoveries to the Astrophysical Journal. The paper is available online here.

If you have been following our blog, you may remember that the SPT is a telescope sensitive to radiation (light) in the microwave region of the electromagnetic spectrum. The telescope is designed to detect the Cosmic Microwave Background Radiation, which is light "left over" from the Big Bang. With telescopes like the SPT, we can map out the microwave sky and study this fascinating record of the early universe. One of the key scientific goals of South Pole Telescope is to search for places where the Cosmic Microwave Background (CMB) light has been distorted by large collections of matter and galaxies called galaxy clusters. When the CMB light passes through a galaxy cluster, its spectrum is changed through something called the Sunyaev-Zel'dovich effect. By searching for the spots in the sky where the CMB is distorted in this way, we can find galaxy clusters and study their properties. If we are able to discover many galaxy clusters, we may be able to use them to learn more about the history of the expansion of the universe, and how it has been affected by the phenomenon known as Dark Energy. That was a pretty quick review, but if you want some more background details, take a look at our webpage.

It takes a lot of work to sort through the raw data from the SPT and make maps of the microwave sky. It then takes even more work to search those maps for clusters! We have only just started the whole data analysis process, but we were excited to immediately see four strong cluster signals in some of the maps that we made from our 2007 and 2008 data. We have detectors that are sensitive to three different wavelengths or frequencies of CMB light (basically three different colors). In the maps made from data taken with our 90GHz and 150GHz detectors, the cluster signature should look like a dark blob. We don't expect to see any sign of the cluster in the data taken with our 220GHz detectors. Having three different "colors" in this way gives us a couple of cross-checks to make sure that what we are seeing truly are clusters and not just features in the CMB itself (or some sort of noise).

Below is the main figure from our recent paper. The top row shows images of the four clusters. The color scale shows the intensity of radiation detected at 150GHz, and the dark blobs in the center are the four clusters. It's possible to filter the maps in order to pick out the cluster signal and ignore more of the background CMB patterns, and the rest of the rows of the figure show these filtered images. The clusters show up in 150GHz and 90GHz, but not at 220GHz, just as expected. The really exciting thing is that three of them are brand new discoveries - only the first one was previously seen by other telescopes.

We're celebrating our first results, but not slowing down! We have a lot of data that we haven't analyzed yet, and there are many more clusters hiding in it waiting to be discovered!

While those of us in the Northern Hemisphere have been hard at work analyzing data and preparing for the next summer season at pole, our tireless winterovers Keith Vanderlinde and Dana Hrubes have been keeping the telescope up and running and performing all of the observations. The sun finally rose at the South Pole not too long ago, and the very first airplane of the season is due to arrive at the pole sometime in the next 24 hours. It will bear, among other things, the first fresh fruits and vegetables that Keith and Dana have been able to eat for 8 months! They've done an amazing job and we all owe so much to their efforts. Hopefully they are both looking forward to vacations in warm locales in a few weeks.

One of the perks of enduring the dark cold winters at the South Pole is being able to experience the spectacular winter skies. Among the photographs that Keith has sent back, the one below has to be one of the most striking. It's almost enough to make you want to winterover!

Monday, February 11, 2008

Back on the sky!

As of February 6, the new and improved SPT receiver is installed in the telescope and looking into the heavens. The last 10 days or so until South Pole Station closes for the winter are being spent characterizing the new array, focusing the telescope, and (this one is really important) making sure our 2008 winterovers Keith and Dana are prepared to run this beast and deal with any situations that might arise. Once these tasks are completed, we will settle into a stable observing routine for the winter season.

As a teaser, here's an image made from one of our regular observations of a galactic HII source:

Saturday, January 19, 2008

We're famous! Final Webcast of the season, the Press and RSS

We had our final Exploratorium webcast yesterday, January 18th. The show is archived on their website in case you missed it. In other exciting news, the Chicago Tribune recently ran a story on the SPT. It was amazing seeing familar faces and photos from the pole splashed across the front page! For those of you not residing in Chicago, the article can be found here. Finally, we added RSS to the blog (thanks to our readers for the suggestion).

Friday, December 28, 2007

Check us out today on NPR!

Talk of the Nation will be doing a piece on the South Pole Telescope this afternoon. Tune in and listen or check their website after 6 (EST) today for the piece.

Wednesday, December 19, 2007

Upcoming Live Webcast: Dec. 21 2007

Be sure to visit the Exploratorium's website for another live webcast from pole on Dec. 21, 2007 at 8 am CST.

Thursday, December 06, 2007

Live SPT-Exploratorium Webcast Tomorrow! (Dec 7th)

Be sure to head on over to the Exploratorium's site tomorrow at 9:00 CST to join us for a live webcast with members of the SPT team at pole. This is a great opportunity to ask SPT scientists questions about their research.

The last few weeks at pole we have been busy characterizing our detectors (Kathryn talks about her work on this here), preparing our receiver for an upgrade and improving the surface of our primary mirror. On the primary mirror, we hope to achieve a surface smoothness of 20 microns (less than the thickness of a human hair), which is quite an accomplishment across a 10 meter dish! Back in the states, we have been busy fabricating and testing new pixels for the camera this season. Here is a (seasonably appropriate) photo of one of new bolometers magnified 500x under a scanning electron microscope (SEM). Click here or here for more information on our detectors. For more on the SEM check out these links (background, gallery).

Monday, October 15, 2007

It has been a while since we last posted but that doesn't mean we haven't been busy. We just finished observing for this season and it was a success! Since deployment lots of exciting things have taken place. The SPT winter-overs, Zak Staniszewski and Steve Padin, have been living at the South Pole running the telescope. Since the SPT detectors operate at very low temperatures, the winter-overs spent part of each day cooling the detectors and setting them. Then, when the telescope is ready to observe, they use a computer to command the telescope to point at the regions of the sky that the collaboration decided to observe this Austral Winter. Each day the data is sent back to the SPT collaboration via satellite and the analysis team sets to work processing the raw data. One of the main goals of the analysis at this stage is to understand how each element of the instrument is working. The telescope is a very complicated instrument and before we are ready to use this data for science, we want to be really sure we understand how everything is working, especially the hundreds of individual detectors making up the camera. The next step in the analysis is to write a complicated set of computer programs that take raw data and process it into maps of the sky. We will be working hard over the coming months to prepare these maps and study them. Besides the analysis, there is a flurry of activity as we work to create an updated receiver to install on the telescope during the coming Austral Summer. Already, the first few members of the collaboration are headed back down to the pole to begin this season's work on the telescope

Below are some great pictures of the telescope during the Austral Winter taken by Zak Staniszewski and Steve Padin.

Spt after storm

The telescope after a storm.

Aurora Sunrise

The aurora, a phenomenon seen most commonly at the poles of the earth caused by the interaction of the solar winds and the particles in the earth's magnetosphere.

Moon over SPT

The moon shining brightly behind the telescope.


The sunrise after a long dark winter. Since the earth's axis of rotation is tilted with respect to the light coming from the sun it is always dark for part of the year at South Pole and always light the other part of the year. For this reason, the sunrise is a very special event.

Sunrise 2

The white snow and telescope looking beautiful as the rising sun reflects off them.

Wednesday, May 02, 2007

The Long Goodbye


Now that the busy polar summer season is over, things have gotten much quieter around here. Although there are just two SPT team members (Zak Staniszewski and Steve Padin) left at pole, there is still tons of work to do! Right now we are busy commissioning the telescope, and thus far everything is progressing well. Here is a shot of the SPT scanning during these early tests:


Be sure to go check out the newly revised SPT Multimedia page where we've uploaded lots of movies and photos from both the test build in the US and construction at pole this season.

Friday, February 02, 2007

Now that February is here, the temperatures at the South Pole Station have begun to drop again, and the station is preparing to close for the winter. Most of the people currently working at the station will fly out within the next couple of weeks, leaving only a core group of "winterovers" here who will stay through the extremely cold and dark months of the Antarctic winter.

The University of Chicago "reflector assembly team", consisting of Tom, Jeff, Joaquin and Ryan, has already left the ice. But many members of the SPT project are still here until the very end of the summer season to work on the receiver, the last few details of the telescope itself, and the software used to control the telescope and interpret the data that we take with it. At the moment, we are busy cooling down the receiver and the secondary optics in order to test how everything works when we put it all together. It's a very busy time, with people working around the clock.

Even though we all tend to be very focused on whatever tasks are currently at hand, everyone in the team finds themselves sometimes just staring at this beautiful telescope and admiring everything that has already been achieved this year. It really is a gorgeous instrument, and it's especially impressive to see how smoothly it moves. From the windows of the indoor laboratories where most of our work is taking place, we can see the last remaining crews who are working on the telescope outside in the cold. To assemble this enormous telescope has taken teams of iron workers, electricians, insulation workers, carpenters, and many other specialists here at the Station and back in the U.S. It's been incredible to be here and see how the whole South Pole Station is pushing for the success of this project.

Before the Chicago reflector assembly team left, we had a chance to take some pictures of them together with the iron workers and telescope specialists who played big roles in the construction of the telescope. Many of these individuals went through the process of test-building the telescope in Texas last summer, and here they are at the completion of the final instrument in one of the harshest places on earth. It's truly a great group of people and they've done an amazing job. All of the rest of us are in awe!