Date: December 15, 2011

Title: Interview with Dr. Michael Wood-Vasey, Spokesperson for the Sloan Digital Sky Survey III

Podcaster: Diane Turnshek

Organization: Carnegie Mellon University


Sloan Digital Sky Survey III

Sky Server Resources

Professor Michael Wood-Vasey

Description: The Sloan Digital Sky Surveys I and II found the distances to millions of galaxies and quasars and mapped hundreds of millions of objects (one quarter of the whole sky in five different colors). SDSS III is collecting and releasing data now (2008 to 2014). Four surveys will each have a different scientific impact. By analyzing SDSS III data, we hope to learn about extrasolar planetary systems, the structure of the Milky Way Galaxy, quasar and galaxy evolution and the nature of dark energy.

Bio: Diane Turnshek teaches astronomy at CMU, Pitt and St. Vincent, and coordinates the physics outreach at CMU. St. Vincent’s planetarium boasts a state-of-the-art Spitz SciDome projector. Diane worked as a planetarium operator at the Carnegie Science Center’s Buhl Planetarium, assisting in the production of shows. In her astronomy outreach efforts, she has visited to schools, libraries, camps, Scouts and Congress. She hosts a monthly public lecture series at Allegheny Observatory. She has consulted with many who wished to keep their science accurate, from authors to opera companies. She is a science fiction author and editor, whose short fiction has been published in Analog Magazine and elsewhere.

Sponsors: Carnegie Mellon University Physics Department is proud to sponsor 365 Days of Astronomy. CMU astronomers hope to explore and explain the mysteries of our cosmos through robust research, teaching and outreach programs.



DT: Hello. Welcome to another installment of 365 Days of Astronomy. This is Diane Turnshek and I’m here today with Dr. Michael Wood-Vasey. He is the new spokesperson for the Sloan Digital Sky Survey III and we’re here to talk about that today. Hello!

MWV: Good morning. Thank you for having me on here. So I’m an assistant professor in the Department of Physics and Astronomy at the University of Pittsburgh. I’ve been here for four years. When I joined the Department, I also chose to join this international collaboration of scientists and astronomers, the Sloan III Survey and, a few months ago, they had an election to elect the new spokesperson for the collaboration. The job of this spokesperson is to present the science and the interest and the excitement of the project to both the public and the astronomical community, to engage the scientists working with other scientists and with the public at large, to share some of the great work in science that we’re doing.

DT: Very nice. So it was an election. I didn’t realize that.

MWV: Yeh, it’s very interesting to see how large international collaborations organize themselves. We tend to believe in essentially democratic principles as such, and so, for positions like this, there is a slate of candidates, that is approved. So there were three other very qualified, very wonderful people running for this position, and then the collaboration as a whole voted for who they thought would best represent the survey or their interests or, I don’t know, who they just met, and it was certainly quite an honor to be selected. And honestly, there are all sorts of great people in the collaboration who could do this, but it’s a pleasure to do it.

DT: How does your particular research tie in with the survey?

MWV: My research interests are in cosmology. I’ve always wanted to know what the universe is made of, what it is doing, where it is going, what the future might hold. Most famously, I suppose, in my own family lore, when I was five and I had just read my first little book about the universe and I told my mom, “Mom, if I ever figure out how the universe works, I’m going to write a book.” So, that’s still my goal. I haven’t started the book yet. These questions about cosmology drew me into supernovae. When I joined and started grad school at Berkeley in 1998, the supernova cosmology project and the high-z search team had just announced their great exciting results that the universe was accelerating in its expansion; it was accelerating faster and faster and we didn’t know why, but supernovae were such a good way to probe this because you could tell the distance to a supernova and thus measure as you looked out in the universe and because, as you’re looking farther and farther out, the speed of light is finite in the universe, and so your looking farther into the past—you can map out the expansion of the universe over time. So this is what I did in my graduate work and my postdoctoral work at Harvard.

So supernovae are great, but my interests are really in cosmology and Sloan III, one of their main surveys is the BOSS Survey, which is using a large spectrograph that can take a spectrum of a thousand galaxies at once. So it looks up in the sky and it uses fiber optics to line up on each star or galaxy and take a spectrum of that galaxy and try to measure its redshift and other properties about it. And this, using the Baryonic Acoustic Oscillation technique, is the jargon, we can also use this to measure distances in a different, a very complementary way to the supernovae and this is one of the exciting things happening right now in the next five years. So cosmology started the whole thing and I hope that cosmology will still see me through.

DT: All right, you mentioned that BOSS is one of the projects one of the surveys that the new Sloan Digital Sky Survey III is doing. There are four all together? Four projects?

MWV: Yes, there are four surveys that are part of the Sloan III endeavor and this was constructed a little differently than previous Sloan things, but with these basic capabilities of having a telescope, having a crew to run it, having a very talented observing crew, data reduction crew, all these things. There was the opportunity to have several surveys happening at once. So, one of them is BOSS, the other is SEGUE, this is a survey that’s studying the stars in our galaxy and they looked at over a hundred thousand stars in our galaxy to try to understand what those stars were made of, how they’re moving in the galaxy and what the history of the formation of star in our galaxy was and the formation of our galaxy itself. In a very related vein, the APOGEE survey is using a newly constructed, near infrared spectrograph to take very detailed measurements of many giant stars mostly in the center of our galaxy and in other places and they are using the infrared because they can see through the dust that obscures our view of the center of our galaxy, so they can see all those stars and understand exactly how those stars are moving and get further information about how our galaxy has assembled, how it’s still in the process of developing. The APOGEE project just started a few months ago, very exciting. And then the MARVELS project is using what’s called the radial velocity technique—it’s using the velocity of stars as they wobble a little back and forth as they’re pulled by any planets that might be around them. It’s looking at several thousand stars in our galaxy, nearby stars, and looking to see how many of them have planets around them. So those are the four surveys of the Sloan III project.

DT: That MARVEL one sounds amazing. They’re looking at stars that are nearby, but are they looking at stars, any particular spectral type of stars? Stars like our Sun?

MWV: Yes indeed, they’re looking at stars very much like our sun; some stars are a little bigger, a little hotter, some are a little smaller and a little cooler, but very much they’re looking at stars like our own, G-stars in the jargon, F, G, and K stars is precisely what they’re doing, if you’ve been studying your stellar classification. And so that’s very exciting, they’re trying to find planets in solar systems somewhat like our own. And one of my interests in that actually just locally is that I have a team of undergraduates who are using a small 16-inch telescope to try to see if any of these planets cross in front of their stars, just dimming the light a little bit. Exoplanets remain an opportunity where amateurs and undergraduates can still make useful contributions and I think it’s really a fun and exciting part of that.

DT: Thank you. The Sloan Digital Sky Surveys I and II were completed and this new survey started in 2008?

MWV: So the Sloan I project, at the time of course just called Sloan, SDSS, ran successfully for many years. Then there’s the Sloan II project, which spent a few years just finishing up some extra spectra and then doing imaging repeatedly on one section of the sky to see what was going to change over time including looking for supernovae.

DT: Oh, that was the one that found a lot of asteroids and things in our solar system.

MWV: Right, exactly. And one of the things, if you look at the same regions of the sky a lot, you’re going to see things that change, either because they change in brightness or they change because they’re moving and so we see the asteroids move across the sky.

DT: Transient objects.

MWV: Transients, yes. That’s what we call them. My wife still makes fun of me for studying transient astronomy, she thinks I’m, I don’t know, studying stars that are down on their luck or something like that, but the exciting part that we’re doing now is we’re studying how things change and in fact, the APOGEE survey, for example, is looking many times at these stars to try to see if any of those stars are moving back and forth, just like the MARVELS project was also using time as the fundamental thing that it’s exploring.

DT: All right. And this will go until 2014?

MWV: Yes, so the Sloan III project is a six-year project, started in mid-2008 and will go through 2014. We’re already starting to think about what’s going to happen next. And things are trying to gear up to get in the works for some the next greatest science that we can do.

DT: Where is the telescope located?

MWV: The telescope is located in Cloudcroft, New Mexico . . . near Cloudcroft, New Mexico. It is a two and a half meter telescope. It was specially designed for this survey, specially designed to be a good survey telescope that can look at large portions of the sky at once, so the field of view, the amount it can look at, is many times the size of the moon. And this survey telescope comes along with all the rest, having the hardware to store all the other instruments that are used, having a whole mountain staff to run the telescope, having observers, and all these infrastructure things are really important aspects of any of these large science things. Sloan III is a forty-five million dollar project with contributions from the National Science Foundation, the Department of Energy, the Sloan Foundation (thus the name), and from the individual partner institutions that have joined up, become part of this.
All the data will become public. We had our first data release, Data Release 8 of the Sloan project overall, but the first for Sloan III, last January. We’ll have our next data release, Data Release 9, next July of 2012 is what we’re shooting for, and we’ll have data releases every year and a half, culminating in a final data release in 2014 that will be all of the data that we have taken over the six years of the project. Because, as much as people joined this project to do their science stuff, there are just so many objects. There are 500 million galaxies that we have identified and catalogued. There are hundreds and hundreds of thousands of spectra of detailed observations of these objects. There’s just more information than any one scientist or and three hundred scientists could do in their career and so some of the public sharing of data’s been such a key aspect of the success and the purpose of why to do something like Sloan.

DT: And there’s educational opportunities, too. There are labs that I use in my class.

MVW: Absolutely. So, back when we were starting to put together data to share with the public, the Sky Sever concept of how do you share all this data, because this is different, people used to just have their few objects and they could keep all that organized in their head. And now with all this data, you had to come up with different ways to access it that were useful to scientists and scientists outside and astronomers. And once we set this up we realized, this means you can make all this data accessible to anyone. And so there is a whole series of exercises, workshops, tutorials that you can do to use that same data that we’re doing to write our papers in the Astrophysical Journal to learn science at the high school, elementary and college level to learn about the stars and the galaxy. So that’s at and you can follow the links and learn all sorts of great things about the universe.

DT: We’ll include links in the show note. Anything else you want to add?

MVW: I find it fascinating to work in the large projects to see how very smart, very talented people chose to organize themselves and work together, sometimes competitively, sometimes collaboratively, but always in the spirit of trying to find out the secrets of the universe and there’s, I think, really an excitement about that. I certainly feel privileged to be a part of this groups and honored to play some small part in representing and trying to share the great science with the wider community and the public.

DT: Thank you. Thank you very much for joining us today. I’m sure our audience has learned a lot and this is Diane Turnshek signing off for 365 Days of Astronomy.

End of podcast:

365 Days of Astronomy
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