Friday, December 29, 2006

BLAST flies again

BLAST, the Balloon-borne Large-Aperture Sub-millimeter Telescope, launched from the McMurdo Research Station in Antarctica on December 21Launched from the McMurdo Research Station in Antarctica on December 21. BLAST will address some of the most important galactic and cosmological questions regarding the formation and evolution of stars, galaxies and clusters.
The Canadian role in BLAST is to design and build the gondola, pointing system and control electronics. This is an ambitious project, requiring the largest payload which can be launched in Antarctica and as fine-tuned a pointing system as has been flown on a balloon in order to take advantage of our diffraction limited optics. We are working with AMEC, who have designed the telescope and gondola.
AMEC has been involved in Canadian astronomy projects since they helped construct the Canada-France-Hawaii Telescope in the 1970s.

BLAST had a flight in 2005 when it was launched from Sweden and landed in the Canadian artic. More information on BLAST can be found on the UBC website.

Friday, October 27, 2006

Shake, Rattle and Roll

The earthquake that rumbled across the Big Island on October 15 has impacted Gemini North, Canada's largest optical telescope. All of the telescopes on Mauna Kea were offline for a short time after the earthquake, but the larger, more sophisticated telescopes including Keck, Gemini and Subaru are still recovering.

Gemini escaped without any serious problems except for its Secondary Control System (SCS). This is a sophisticated piece of electro-optics that controls the motion of Gemini's high technology secondary mirror. The secondary mirror can perform high-speed tip-tilt motion to correct for windshake and a small amount of atmospheric turbulence. The SCS also performs chopping where the mirror moves quickly back and forth between two points close separated on the sky during mid-infrared observations.

Recent tests of the SCS have demonstrated that the problem detected a few days ago is very likely due to a bad position sensor and/or associated cabling. Unfortunately these components are deeply embedded within the tip/tilt system and Gemini must remove the secondary mirror from the telescope and perform the necessary repair work in the summit lab. Given the time needed to remove the secondary from the telescope, receive new parts, install them, then mount the secondary mirror assembly back on the telescope, Gemini North will be shutdown for at least 2 more weeks. When the secondary mirror is repaired and night-time tests are possible, we still must make a variety of telescope performance tests before going back into science operations.

Thursday, October 19, 2006

Canadian Astronomers Score in Imaging Contest

Canadian astronomer Jayanne English of the University of Manitoba has won the Second NRAO astronomy image contest. Jayanne's striking image of an enormous bubble blown into the dusty gas disk of our own Milky Way galaxy used data from the Very Large Array and the Greenbank Telescope

Canadians did very well in the contest taking three out of five honourable mentions. The image contest is part of a broader NRAO effort to make radio astronomical data and images easily accessible and widely available to scientists, students, teachers, the general public, news media and science-education professionals.

Friday, September 29, 2006

Champagne Supernova in the Sky

This article is not about the Oasis song but about the discovery of a peculiar supernova. The conventional view is that supernovae of type Ia are the explosion of a white dwarf that has exceeded the so-called Chandrasekar limit. An international team of astronomers led by Canadians has discovered a possible super-Chandra supernova.

The type Ia supernova are of special interest as they are being used as standard candles to measure the expansion of the Universe. Now a team of astronomers led by a group at the University of Toronto has discovered a supernova more massive than previously believed possible. Andy Howell, lead author of the study, identified a Type Ia supernova in a distant galaxy 4 billion light years away that originated from white dwarf whose mass is far larger than any previous example. University of Oklahoma professor David Branch has dubbed this the “Champagne Supernova,” since extreme explosions that offer new insight into the inner workings of supernovae are an obvious cause for celebration.

Friday, September 15, 2006

Star Counts from the Shuttle

Most people have looked up at the dark night sky and have been amazed by the number of stars you can see. What if you were to try that from the Space Shuttle? Canadian astronaut Dr. Steve MacLean will do that during the current shuttle mission.

Dr. McLean had over 600 students do exactly this experiment this summer as part of the Star Count Project organized by NASA and the Canadian Space Agency.

Tuesday, September 05, 2006

Thirty Meter Telescope News

As I've mentioned previously, Canada is a equal (25%) partner in the Thirty Meter Telescope (TMT) Project. The TMT is the world's most ambitious optical telescope project and we can expect the first science images from the telescope in about 2015.

The TMT Project publishes monthly electronic "Newscasts" which cover various aspects of the project. The August issue covers a range of topics including science, technical and management. One article describes how the Project is undergoing a huge cost estimating exercise. The goal is to come up with an accurate cost estimate for the telescope and to have this estimate reviewed by experts later this year.

This issue contains an excellent article by Dr. Tim Davidge of Herzberg Institute of Astrophysics (HIA) in Victoria on studying stars in the Andromeda Galaxy with adaptive optics powered imaging camera on TMT. TMT will have four times the resolution of the Hubble Space telescope and will be able to image stars that are much fainter.

The cover of TIME Magazine declares "How the Stars Were Born" and the accompanying article features TMT Board member Richard Ellis. TMT will greatly enhance our understanding how stars, and galaxies, are born.

This issue of the TMT Newscast includes a Q&A with Dr. David Crampton who is the Instruments Group Leader for TMT and is also the Head of Instrumentation at HIA.


Friday, September 01, 2006

Pluto, 1930 — 2006, RIP

While not necessarily a Canadian story I feel I must make some comments on the planet definition issue. After all, I was one of the IAU members in Prague who actually voted on the four resolutions on the definition of a planet and other Solar System bodies. There are a number of Canadian astronomers who work on Solar System bodies. The Canada France Ecliptic Plane Survey is undertaking a careful survey of Kuiper Belt Objects, of which Pluto is now recognized as the prototype.

The initial Resolution presented to IAU members was seriously flawed. There was wide agreement that something better was needed and this was voiced very vigorously in the Tuesday lunch hour discussion the last part of which is very interesting to watch. The original resolution totally ignored the dynamics of bodies in their definition. After all planets and all other Solar System objects do move!

Personally, I think after the disasterous initial proposal the process to reach the final four Resolutions was much too quick. The IAU should have tabled the issue until the next General Assembly in Rio de Janeiro and set up a more balanced Committee to go back to the drawing board.

I don't think we've heard the last of this and there is a petition of scientists who want to overturn the new IAU definition.

For everyone's information I voted YES, NO, YES, NO on Resolutions 5A, 5B, 6A, 6B.

Tuesday, August 22, 2006

Faint, Fainter, Faintest

Astronomers are always observing stars or galaxies that are faint, i.e., not very bright. This is usually because by pushing the limit we learn more about the Universe. A team of astronomers led by Harvey Richer from UBC have used the Hubble Space Telescope to observe the faintest stars ever observed, in the globular cluster NGC 6397.

Their research revealed the lowest mass stars on the main sequences in this cluster. These are the smallest stars that will burn hydrogen through fusion and live many billions of years rather than simply fading away after 1 billion years or so.

Richer and colleagues also detected a characteristic change in the color of white dwarfs in the cluster that is related to the onset of molecular hydrogen being formed in the cooling atmospheres as the white dwarfs die. With this information in hand, astronomers can learn more about the physics of low mass stars and white dwarfs and perhaps improve the estimate of the ages of these stars and the universe.

Thursday, August 10, 2006

Planets Without Stars

Astronomers have always thought that objects with the mass of planets orbit stars, or failed stars, know as brown dwarfs. Now a discovery by a team led by a University of Toronto researcher, Ray Jayawardhana, has shown otherwise.

The team's discovery of a seven-Jupiter-mass companion next to a planetary mass object, only twice its mass. Both objects have masses similar to those of extra-solar giant planets, usually found in orbit around a star. Unexpectedly, these bodies appear to circle each other.

The team discovered the companion candidate in an optical image taken with the European Southern Observatory’s 3.5-meter New Technology Telescope on La Silla, Chile, and investigated it further with optical spectra and infrared images obtained with ESO’s 8.2-meter Very Large Telescope on Paranal, Chile. These followup observations confirmed that both objects are young, at the same distance, and much too cool to be stars. The existence of this wide pair poses a challenge to a popular theory which suggests that brown dwarfs and planemos are embryos ejected from multiple proto-star systems.

Wednesday, August 02, 2006

A Tale of Two Telescopes

Those familiar with sky probably know of Castor and Pollux the Gemini Twins. Well, there is another pair of Gemini twins in the Universe and those are the twin 8-meter telescopes operated by the Gemini ObservatoryGemini NorthGemini is unique in having telescopes in both the northern and southern hemispheres giving astronomers access to the complete sky.

The Gemini Observatory runs two of the world's largest telescopes, Gemini North (located on the extinct volcano Mauna Kea, on the Big Island of Hawaii) and Gemini South (located at Cerro Pachon, in the Chilan Andes). These telescopes use the latest technologies to achieve the best performance possible. The Gemini telescopes are optimized for both image quality and performance in the mid-infrared.

Image quality refers to the sharpness of the stars imaged by the telescope. The earth's atmosphere naturally blurs slightly images taken by telescopes. However, astronomers have developed a technique called adaptive optics which mostly corrects for this blurring effect.

Gemini South

Mid-infrared astronomy is very challenging. Think of it as trying to look through an optical telescope at mid-day on a snowy field which reflects all of the sunlight. The problem is that everything on the telescope is emitting at the wavelengths at which you are trying to observe. Gemini has taken great precautions to ensure that as little of the telescope emission finds its way into the camera. The two Gemini telescopes are the best performing telescopes on the planet today.

Don't worry if you are unable to visit either of the Gemini telescopes. There is a Virtual Tour available on CD for the cost of an e-mail.

Monday, July 31, 2006

Billions and Billions of Stars

One of the important measurements astronomers make is the brightness of stars. Originally this was done by eye. When astronomers started using photographic plates, special devices were used to measure the brightness of stars. Today, computers combined with powerful software are used to measure the brightness of stars, called photometry on CCD images.

Dr. Peter B. Stetson, of the National Research Council, was recently elected a Fellow of the Royal Society of Canada, the Academy of Arts, Humanities and Sciences of Canada, partly for his photometry software call DAOPHOT. DAOPHOT was developed especially to do photometry on stars which are very close together or even overlapping. Since it's initial release in 1985, DAOPHOT has been used by thousands of astronomers to measure countless billions of stars on millions of CCD images. A Google search for DAOPHOT returns over 78,000 hits. Dr. Stetson's paper describing the DAOPHOT software is the most highly cited paper in astronomy for 1987 with over 2,100 citations.

Dr. Stetson himself has applied it to the study of the ages of stars and to the determination of the age of the universe from its expansion rate. On all these topics he is considered a leading authority.

Friday, July 28, 2006

16th Kingston Theoretical Astrophysics Meeting

The 16th "Kingston" meeting was held recently in, hold your breath, Kingston. While this may seem obvious the "Kingston" series of meetings on theoretical astrophysics are not always held in Kingston. The series got its name after the location of the original "Kingston" meeting.
DickThis meeting was special as it celebrated the 65th birthday of Professor Richard Hendriksen, a preeminent theoretical researcher from Queens University. This year there were 68 attendees, with one person who made it over the pond from Leiden (Netherlands).

The Wednesday of the conference was humourously dubbed "Henriksen Fest"
and all the presenters were able to highlight contributions made by Dick to their respective fields. Jim Stone got things going with the first keynote session and did an admirable job as session chair for the morning.
Excellent presentations by Shantanu Basu, Ralph Pudritz (keynote) and Peter Martin filled up the rest of the morning. As part of a surprise for Dick Henriksen, Alan Bridle was present for the afternoon session and the banquet in the evening. The final event of the afternoon was a special lecture by Dick on when we can expect scale invariance.

The banquet was attended by over 70 people, with friends and colleagues from throughout Dick's career attending. Larry Widrow was an informal master of ceremonies and a series of roasts were gleefully given. The evening was broadly divided into Dick's career at Queen's and his involvement in the founding and running of CITA. Both Dave Hanes and Alan Bridle recounted stories of some of Dick's less well considered ideas at Queen's (spending the winter on a wooden boat on Lake Ontario being one of
them!) Peter Martin and Dick Bond then followed-up with stories from the anuls of CITA. Following some impromptu congratulatory remarks from former students and colleagues, Stephane Courteau presented the "Henriksen Love Fest 2006", a series of slides reflecting on Dick's lighter side and the evening was concluded with the presentation of a series of gifts, including a new chainsaw for Dick to wreak havoc on his land!

Although the Wednesday was the centrepiece of the conference, the other sessions was also well attended and the planetary on session on the Tuesday morning got things off to a great start. The cosmology session on Thursday was also a highlight with summaries of the new physics coming out of the Cosmic Microwave Background, as well as galaxies and galaxy surveys, being given. Perhaps the only down side to the conference was that all but one of the panel sessions evaporated as questions asked during the presentations ate into the allotted time!

Thursday, July 27, 2006

Thirty Meter Telescope News

I've mentioned the Thirty Meter Telescope (TMT) in an earlier post. Canada is a 25% partner in the TMT project, which is currently in the Design and Development Phase. The latest TMT Newscast's focus is on site-testing. Deciding where to put your telescope is extremely critical - you only get one chance to pick the right spot. Besides lots of clear skies, a good telescope site will be one with minimal atmospheric turbulence, which will allow the telescope to produce excellent images. Other factors that are important include: wind speed, height of the mountain, accessibility, available infrastructure, and impact on operating costs.

The newsletter also talks about cosmic reionization. We see the Universe as it is today because it is transparent to ultraviolet photons. Thirteen billion years ago the neutral hydrogen gas was ionized making it tranparent to these photons. How and when it happened exactly is something that we don't understand. When did this remarkable event happen? What role did the first star-forming galaxies play and how did those early systems develop to become the galaxies we see at later times? These are some of the questions researchers using the TMT and other facilities are hoping to answer.


Tuesday, July 25, 2006

The Universe in a Computer

Unlike other sciences, astronomers can't go to the lab and do experiments - we have to passively observe the Universe. The increasing power of computers and the development of sophisticated computer codes have allowed numerical simulations to emerge as one of the key components of modern astrophysics. It is now possible to run an experiment on a computer and see what happens when galaxies collide, or watch the development of a proto-planetary system around a young star, or follow what happens to gas as it falls into a black hole.

Canada's Institute for Computational Astrophysics (ICU) located at Saint Mary's University is a leader in this increasingly important field. Researchers at the ICU study areas such as modeling the inner workings of stars, understanding the structure of stars by studying how they vibrate and the dynamics of our solar system.

Monday, July 24, 2006

Observing the Cold Universe

Astronomers observe the Universe over a wide range of the electromagnetic spectrum from gamma rays to x-rays to the ultraviolet visible and infrared. The JCMT views the sky in the submillimetre region of the spectrum, i.e, at wavelengths just under a millimetre. At these wavelengths, the telescope can detect objects in the dusty regions in space that would normally be obscured at visible wavelengths. Because the wavelength of radiation is related to the temperature of its source, submillimetre measurements can reveal something about cooler objects in space (-263 C), like interstellar dust.

JCMT revolutionized our understanding of the cold Universe with an innovative instrument called SCUBA. SCUBA observations have helped open up a whole new area of study – that of the evolution of early galaxies. As revolutionary as SCUBA was, later this year its successor SCUBA2 will be delivered to Hawaii. SCUBA2 will be much more sensitive than SCUBA and will be able to produce images up to 1000 times faster than SCUBA.

Canada is a member of the consortium building SCUBA2 with work being done at the University of Waterloo and the University of British Columbia among other places.

Friday, July 21, 2006

Canadian Astronomy Education

Two subject that most kids find interesting at some point are dinosaurs and astronomy. For many the interest in astronomy remains even as they move into other careers. If I want to have quiet time on a plane I know that I can't tell the person sitting next to me that I'm an astronomer.

Astronomy is part of the curriculum in all provinces. The Canadian Astronomical Society has established a very nice web site for Canadian Astronomy Education that provides resources for students, teachers, youth groups and others. The site contains information from the history of Canadian astronomy to Canadian contributions to a guide to careers in astronomy. For teachers there are lessons plans and project ideas. For students there are links for learning more about astronomy, ideas for science fair projects and the Canadian Junior Astronomer Program

Thursday, July 20, 2006

Jupiter's Giant Red Spot has a Buddy

In January 1610 Galileo used the latest technology, a new invention later named the telescope, to look at Jupiter. In doing so he changed our perception of the Universe by discovering four objects that orbited Jupiter rather than the Sun. Fifty Years later Cassini discovered the Great Red Spot on Jupiter.

Astronomers are still studying Jupiter today, both with ground-based telescopes and with space missions such as the aptly named Galileo mission. Today the Gemini Observatory released an image of Jupiter taken with their state-of-the-art adaptive optics system, Altair. Adaptive optics corrects the distortions introduced by looking through the atmosphere and allows telescopes on the ground to perform almost as well as telescopes in space. This animation provides a brief overview of how an adaptive optics system works. [2.73 MB Quicktime Movie]. The Altair system was built by the National Research Council in Victoria.

The Gemini image shows that the Giant Red Spot now has a companion named Red Spot Junior. Both are massive storm systems that are a product of strong convection currents that violently swirl gases in that region of the planet's atmosphere - very similar to hurricanes on Earth. Read more details.

Wednesday, July 19, 2006

Understanding Dark Energy

Yesterday I mentioned that the CFHTLS was using distant supernova to study the mysterious dark energy. The Supernova Legacy Survey (SNLS), as it is referred to, will detect hundreds of supernova out to a redhift of 1. SNLS uses Type Ia supernovae as standard candles to study the acceleration of the universe. Supernovae at high redshift are very faint.

SNLS detects supernovae by comparing the current image of a patch of sky with a template image taken previously. ? A computer program studies both images looking for new stars. Can you see the SN in the image to the far left which is not in the other image?

In order to use the SN to study dark energy we need to know the distance to the supernova. Since we (think) we know how bright the SN are intrinsically the measured peak brightness gives us a direct measurement of the distance. We also need to measure the reshift of the SN from a spectrum. This requires the largest optical telscopes in the world such as the 8-m Gemini. Some of the spectra from Gemini of detected SN are to the left. The measured spectra are the very squigly lines while the smoother line is the fit of a template SN spectrum.

The SNLS group published their results in late 2005 based on the first year (out of five) of SNLS data. These results already place the tightest constraints on the nature of dark energy when combined with the results from WMAP. SNLS is a good example at how astronomers are using data from several telescopes, both on the ground and in space, to tackle the challenges in understanding the Universe.

Tuesday, July 18, 2006

150 Terabytes and Growing

The instruments astronomers use today produce data at a, well, astronomical rate. We have also realized over the past 20 years or so that the digital data can be very useful for research beyond what the original investigator intended. Thus, the growing importance of data archives. One of the largest collections of astronomical data is located in Canada at the CADC. The CADC began in 1986 as one of three archive sites for the Hubble Space Telescope. It now archives data from several ground-based telescopes as well.vWhile the CADC still archives Hubble data the largest volume of data now comes from the Megacam camera at the CFHT

Megacam is a 340 Megapixel camera and each image it produces is approximately 750 Megabytes. The Canadian and French communities are undertaking very ambitious, five year research projects with Megacam, called the Canada-France-Hawaii Telescope Legacy Survey. One of the projects uses distant supernova to understand the nature of the recently discovered dark energy.

Monday, July 17, 2006

Canada's First Space Telescope

It's been just over three years since Canada's first space telescope was launched atop a former Russian ICBM. MOST (Microvariability and Oscillation of Stars), also know as the Humble Space Telescope because of its diminutive size, is able to measure brightness variations in stars to 1 part in a million! If you look at a streetlamp 1 km away and then move 0.5 mm closer the lamp has changed by one part in a million. Below is MOST and it's project scientist, Jaymie Matthews of UBC.

Astronomers have learned a lot from variable stars over the past one hundred years and MOST's sensitivity will allow astronomers to make advances in some pretty basic and essential areas. Can we understand our Sun in the context of other stars? By putting a birthdate on the oldest stars in the solar neighbourhood, can we set a limit on the age of the Universe? How do strong magnetic fields affect the physics of other stars and our own Sun? What are mysterious planets around other stars really like? How did the atoms which make up our planet and our very bodies escape from stars in the first place?

Saturday, July 15, 2006

Choosing Instruments for the Thirty Meter Telescope

There is a very important meeting happening in Pasadena, California next week. That is when the Science Advisory Committee of the Thirty Meter Telescope (TMT) will decide on the first instruments for the TMT.

The TMT is a project that brings together the Caltech Institute of Technology, the University of California, the general US community through AURA and Canada through ACURA. Caltech and UC are the people that built the Keck telescopes. Each of these four partners have an equal share in the project, which means that Canada will have 25% of the telescope time on this behemoth when it is completed in 2015.

While the aperture of the telescope determines its light gathering power (size does matter!), it is the instruments that provide the astronomers with data they can analyse and solve the mysteries of the Universe.

So how do you go about choosing instruments for the world's largest telescope? The process starts with defining the science requirements of the telescope, i.e., how well the telescope will perform in terms of image sharpness, etc. Then the astronomers decide on what the big science questions will be 10 - 15 years ahead and what instruments will be needed to address these questions. Of course, trying to predict the big science questions that far in advance is a little like reading a crystal ball but it does set challenging requirements for the instruments. Once a suite of instruments have been sketched out they are ranked in terms of their priority and the top several are developed into conceptual designs. At this stage, you know a lot better how well the instrument will perform and how much it is likely to cost. Of course it costs a few $100,000 to get to this point.

Now with all this information in hand the SAC will make recommendations for the first instruments for the TMT.

Friday, July 14, 2006

Centre of the Universe

Many of you who live in Toronto may think that you are the Centre of the Universe but in fact the Centre of the Universe lives in Victoria! The Centre of the Universe (CU for the locals) is the astronomy interpretive centre located on Observatory Hill next to NRC's Herzberg Institute of Astrophysics.

At the CU you can tour the 1.8 metre Plaskett telescope (it was the largest telescope in the world when it was built), try some of the interactive displays, or experience a special theatre presentation - the Falling Asteroid Blues, the Backpacker’s Guide to the Universe, or another one of the entertaining multimedia shows. The CU hosts star parties everynight this summer and you can do some awesome star gazing through one of the CU telescopes.

Thursday, July 13, 2006

Canada Ranked #1 in Astronomy

As Dennis Overbye noted in his 2005 New York Times article, "Those nice people up north are taking over the Universe". In February 2005 Canada was ranked as the top country in the world in astronomy based on how often Canadian research papers are referred to by other astronomers. The study was published by the Institute for Scientific Information which tracks this kind of thing. The Canadian Astronomical Society issued a press release on this at their 2005 annual meeting in Montreal. Issuing a press release announcing "we're #1" is very un-Canadian but the truth is that Canadians are doing lots of great research and have built some of the world best telescopes and instruments. The latest article in the press noting Canada's ranking appeared on Canada Day.

In this blog I will try and keep you informed about the work of Canadian astronomers: their research, their new projects and their plans for really taking over the Universe.