Canadian Astronomical Society Conference 2018; Victoria, BC

Hi everyone!

We (Anita and Deborah) attended the annual meeting of Canadian astronomers last month — the Canadian Astronomical Society (CASCA) 2018 conference — along with a crew of other Astronomy & Astrophysics PhD graduate students from the University of Toronto and the Dunlap Institute.  The meeting took place in beautiful Victoria, British Columbia, one of the hubs of Canadian astronomy!   It was a special CASCA this year as it was the 100th birthday of Dominion Astrophysical Observatory (DAO) in Victoria!

On the first day, we attended the graduate student workshop, where we learned about data analysis methods and applied them on real data.  In addition, we interacted with representatives from companies in industry who work with astronomers to build instrumentation for telescopes.  We learned about how astronomers and industry make a vital team to forwards Canadian astronomical science while also giving back to the Canadian economy and establishing Canada’s place on the global scientific forefront.

During the following days of the conference, we attended a series of scientific presentations from astronomers across Canada, including presentations from graduate students from Dunlap and U of T.  Shout out to graduate student Jielai Zhang from Dunlap/U of T for winning a “Best Presentation” prize and Victor Chan from Dunlap/U of T for winning a “Best Poster” prize!  It was an amazing opportunity to learn about the astronomy and astrophysics science that is going on in Canada.

Midway through the conference, we visited the Royal British Columbia Museum with a welcome with Indigenous dances. The museum exhibits we toured were Victorian style and had models of how houses were back in the days as well as shops, roads and industry.

Royal British Columbia Museum exhibit. Image credit: Anita Bahmanyar

We attended presentations about the current status of telescopes that Canadian astronomers are strongly involved with (such as the Canada-France-Hawaii Telescope, the Gemini Telescope, and the Square Kilometer Array), discussing future strategies and the ongoing programs at the telescopes.

On the last night, we visited the DAO and celebrated its 100th birthday with a dome-like cake. We then wandered around, looked at the planetarium and looked through the smaller telescopes that are used for outreach.  We observed Jupiter and its four Galilean moons then headed back a bit after it was dark.

 

Celebrating the 100th birthday of the DAO!

The DAO!

Looking out from the observatory.

Throughout the conference, we interacted with our Canadian fellows in astronomy – not only networking but also forming friendships and strengthening bonds with each other.  It was a wonderful learning experience, and we look forwards to going back next year!

 

At the DAO! From left to right: George, Alysa, Ayushi, Emily, Victor, Rob

From left to right: Ayushi, Victor, Anita, Emily. And Chris Hadfield, of course!

Clear skies,

Anita & Deborah

Synthesis Imaging Workshop at the Very Large Array

Hi everyone, Dana Simard here! I’m a PhD candidate at the University of Toronto, and I study how the light from pulsars interacts with the interstellar medium using Very Long Baseline Interferometry, a radio astronomy technique where we observe the same part of the sky with many different telescopes all around the world in order to get very high spatial resolution – the same spatial resolution we’d get if we had a telescope the diameter of the Earth.  A few weeks ago, I went to Socorro, New Mexico, for a workshop on synthesis imaging, the process of going from the signal measured at all of the different stations to an image of the sky.  The Synthesis Imaging Workshop held in New Mexico by the National Radio Astronomy Observatory is one of the biggest summer schools on this topic, with 150 people from all around the world attending.

Our first few days were filled with lectures on everything from the basics of radio astronomy, how to build a radio detector, and how to properly calibrate your radio interferometric data to get the most accurate and precise image that you can.

Over the weekend, we had a much needed break from the torrent of information to check out the local surroundings and the VLA.  On Saturday, we got out to a local nature reserve, the Sevilleta National Wildlife Preserve, to get a sense of the nature and what it’s like to hike in the desert in 37 degree ‘spring’ weather.  The nature reserve, being far from the nearest city and all of the cellphones and wifi signals in them, is also a great site for a radio observatory and home to one of the Long Wavelength Array, or LWA, stations.  The LWA observes down the lowest frequencies that can be observed from the Earth, from 10 MHz to 88 MHz. By combining all of the telescopes, the LWA observes entire sky all the time.  Curious about what this looks like? You can check out the LWA TV! After our hike, we headed back to Socorro for a star party. Since Socorro is very dry and high elevation (1400 metres), there is little moisture in the air to distort the stars, and the sky is remarkably clear.

Our hike through the Sevilleta National Wildlife Preserve.

The Sevilleta Long Wavelength Array station consists of 256 of these antennas.  Instead of a conventional radio dish, wire mesh is placed under each antenna. Since the LWA observes at wavelengths between 3 and 30 m, this wire mesh reflects the light that the LWA is sensitive to back up to the receiver.  By combining all of these receivers together, the LWA is makes a map of the entire sky all the time.

Getting ready for a star party at the Frank T. Etscorn Campus Observatory.

On Sunday, we got an early start to head to the Very Large Array (VLA) for the entire day.  This is a network of 27 antennas, each 25 m in diameter spread out in a Y-shape 36 km across.  Each antenna has many receivers, so that the VLA can observe all the way from 58 MHz to 50 GHz.  Luckily for us, one of the telescopes was not observing on Sunday, so we got to climb up to the top of the antenna, and check out the receivers. The largest one, bigger than me, observes in L-band, around 1.2 GHz, which is where the 21-cm signal used to map neutral hydrogen gas lies.  As we go to smaller and smaller wavelengths, towards the infrared, the receivers are smaller and smaller. The VLA dishes have a unique set-up for change receivers.  Most dishes have a rotating receiver wheel that moves the receiver you want to the secondary focus.  Instead, the receivers at the VLA are fixed, and the subreflector, which reflects the light from the primary focus back to the secondary focus, is asymmetrical.  By rotating the subreflector, the light can be focused into different receivers.  I mostly observe around metre wavelengths, and the (P band) receiver I use is actually near the prime focus, the little silver and red dipole. It shares this space with another receiver, called the 4 band receiver, which observes the lowest wavelengths and overlaps with the LWA band.

Inside a VLA dish.

The last three days of the conference were a mix of hands-on tutorials and more advanced classes, on things like how to construct an image when you’re observing over a very large range of wavelengths and what kind of problems can come up when you observe at very long wavelengths.  We got to practice making images from both the VLA and the Very Long Baseline Array (the VLBA) with expert help! It was awesome to get to go through the whole process with the opportunity to ask questions along the way.

Heidi Medlin helping me make an image of Supernova Remnant 3C391 during the VLA data reduction tutorial.

My finished image of the quasar 3C 380 during the VLBA data reduction tutorial.

And with that, we were done, and on the route back to Albuquerque to fly home after a busy week filled with lots of astronomical learning!