Intellectual curiosity

Mention to a stranger that you study astronomy, invariably the first thing people ask you is “what sort of job will that get you?”. I usually give some answer along the lines that the jobs out there are in research.

If I said I was a music major then people would assume I was going to be a musician. But when you tell them you are an astronomy major, they mustn’t grasp the idea that you are going to be an astronomer. Such a job just doesn’t seem to exist to them.

It does seem like to a lot of people, university is a “job factory”. You go there to get a degree so that you can get a job as an accountant or an engineer or a doctor. But I’m at university to learn. To learn about the world and in particular astronomy.

I think this is why I don’t think it is outrageous when someone gets $NZ96,000 to study bogan culture. Or to spend €1.5 billion on the Square Kilometre Array. If someone can get that sort of funding, good on them!

(I had an experience recently of watching a news item about the Square Kilometre Array and another person complaining that all that money could be spent on feeding the children. Of course we were watching this on a giant HD television, inside a 3-bedroom house in which only two people live…)

I’m now in the UC Research Repository

This was fun to discover this morning: my thesis is now in the UC Research Repository for all to see.

It has been given the unique handle of http://hdl.handle.net/10092/2684, so I’ve updated all my links to point to there.

“Dancing” T-Handle

This video was used by someone at the department conference with relation to changing neutrino states (or something…).

Thoughts from the Department Conference

Today and yesterday were the 26th Department Conference of the Department of Physics & Astronomy. This year seems to have a particular focus on the post-graduate students. Our HOD is away, along with my supervisor who is the Dean of Science. Very few of the academics are giving talks. So it has been left to us post-grads to give a idea of what sort of research is going on in the department.

I gave my talk yesterday afternoon and it was well received, with lots of questions at the end. Unfortunately due to a technical error my talk was not videotaped so I cannot add it here for all to see.

And this is a real pain since my talk awarded the B.G. Wybourne prize for the best talk of the department conference! Now I have $200 of book vouchers to spend.

Thank you to Mike Dickison of the Learning Skills Centre of the University for your seminars on oral presentations. I took your lessons to heart and the produced what I thought was the best presentation I’ve ever given.

What follows in an unfortunately negative description of the things I noticed from sitting through a couple of sessions of talks.

My number one pet peeve on presentations is ending on an acknowledgment or “Thank you” slide. Now of course you should be thanking the people that gave you support, money and resources. But isn’t the point of your talk to tell us your wonderful results or what your PhD is going to be about? I think you should keep up your summary slide for as long as possible.

To continue that thought, make sure you have a nice tidy sentence to sum up your presentation. I think this is one of the most important lesson from Mike’s seminars — have a “take home” message. Even though everyone will forget everything else you said, but hopefully they will remember that they saw this fanscinating talk today from a guy who going to using a Fabry-Perot for finding chemical abundances in stars.

The laser pointer should be banned. It is not your friend when giving a talk. Grab a stick and physically point at the screen. I’ve seen people with the laser pointer wildly waving it around to indicate something on the screen. I like to mime being a cat crazily following it across the screen. This year I went with the long stick and I think it worked well. You can much more delicately indicate that item of interest on the screen.

Try to keep the number of words and equations on the screen to a minimum. And if you absolutely must have an equation up there, make sure you explain every symbol unless it is something that we all learn in first-year physics. Too many people had five slides in a row of random equations that I don’t think add much.

A number of talks suffered from what I like to call “chicken chicken chicken“. Where you have some piece of jargon that is used throughout the talk and becomes an utterly meaningless word. And was only explained for about five seconds right at the start. One thing I decided to do this year was have a blank slide. While this was on the screen I used my hands to explain a Fabry-Perot. I thought this would be a good way to get everyone to focus on me as I explained this chicken chicken term.

One person at the start declared that at previous conferences people not involved in their research area had said it was boring and hard to understand. His response? It wasn’t to make it more accessible and more interesting. It was to include holiday photos. Seriously we all have physics degrees here. Bring it back to a base level. Make us interested in why you want to do this. How are you going to get funding from general funding sources if you can’t make it interesting?

Deposit my thesis in the library

After waiting six months for the result I was awarded a Masters of Science with Merit. According to the University regulations:

Where the candidate has offered Part II only, by thesis, and in the opinion of the examiners the thesis shows special merit, they shall recommend that the degree be awarded with Distinction or Merit…

Today I deposited by thesis in the library, the last step I had to do before being awarded my Masters of Science. Onwards to December when I get to shake the Chancellors hand and be conferred with the degree.

So now I just need to wait for it to turn up in the University of Canterbury Research Repository.

What is SALT?

SALT is the Southern African Large Telescope, located in Northern Cape, South Africa. It is about 1750m above sea level near the small farming town of Sutherland. It is where I plan to be acquiring some of the data for my PhD.

It is the largest single optical telescope in the Southern Hemisphere with a main mirror diameter of about 11 metres. The main mirror is not one giant piece of glass — it is composed of 96 hexagonal segments, that fit together like a giant honeycomb. The black spot hexagon in the photo below is a missing mirror segment.

Even though it is one of the largest optical telescopes in the world, it was actually built for about 10% of the cost of other telescopes its size. This cost saving came from a trade-off. Instead of being able to tilt the mirror to any angle, the telescope was built at a fixed angle (in this case 37 degrees from the horizontal). On the engineering side of things, this is much more simple as you do not have to create a system capable of tilting several tonnes with a precision of the width of a human hair (or less). But it does mean that with SALT we are limited to how much of the sky we can observe.

The instrument I am going to be using is the Robert Stobie Spectrograph. Here it is sitting above the mirror in 2005:

The construction of SALT was funded by a consortium of international partners, including the University of Canterbury. So that means, astronomers at Canterbury get guaranteed observing time at the telescope.

Other journals have much more … “interesting” articles

Reading astronomy articles you get used to seeing titles like “The phases of X-ray emission of RS Oph” or “Probing populations of red giants in the galactic disk with CoRoT“. Not exactly dinner time conversation starters.

So it was fun scanning through the article titles of the Archives of Sexual Behavior. The reason I was reading this journal was that a news article had said some things that I thought were a bit over the top and guessed that it was a case of the university PR department being a bit keen to make some research more interesting.

In the end I couldn’t find the article that was being talked about in the news article, but did come across “Ballpen into the Bladder of a Woman Due to Sexual Practice” — a cautionary tale if I ever did read one!

Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. II. Stellar Metallicities

As part of the my masters I received data from Naseem Rangwala and Ted Williams. They had used the Rutgers Fabry-Pérot system on the CTIO 1.5 metre telescope to observe the CaII 8542Å line. So I spent a large amount of time playing around with their data to recreate their results and generally learn the ways of reducing FPI data.

Now they have published a paper on that data, currently available only in preprint from ArXiv.

They had extra information that we didn’t have for a large amount of the reduction process so have gone a lot further. The aim was to “show that reliable absorption line strengths can be measured using FP spectroscopy”, which they were successfully able to do.

The main part of the paper was showing the calibration that was needed to take equivalent width and transform them into [Fe/H] metallicities. One of their fields of view incorporated the outer region of the globular cluster NGC 6522. I am not sure if it was intentional on their part on the placement of the FOVs but it did provide them an independent value for comparison.

Overall the results they found were that the FPI gave an [Fe/H] = −0.81±0.10 dex for the cluster, compared to [Fe/H] = −0.91±0.06 dex (Zoccali et al 2008). They considered this to be an “excellent agreement”.

For me the most important sentence comes in their conclusion

“We showed that reliable line strengths can be obtained for hundreds of stars with this technique, allowing future FP observations to measure accurate radial velocities and line strengths simultaneously….”

This is what I hope to do with my PhD except for s-process element abundances. Rangwala and Williams think that with SALT they will be able to measure greater than “2000 stars along a single [line of sight] in an hour of observing time”. This would be a fantastic result for a globular cluster like 47 Tuc.

References

• Rangwala, N., and Williams, T. B.: Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. II. Stellar Metallicities, ArXiv e-prints, June 2009
• Zoccali, M. et al.: The metal content of bulge field stars from FLAMES-GIRAFFE spectra. I. Stellar parameters and iron abundances, A&A 486, 177–189, July 2008

Rangwala, N., and Williams, T. B.: Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. II. Stellar Metallicities, ArXiv e-prints, June 2009