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Nichol and Matt go to Chile!

Archive for astronomy

Clusters, Courses and Everything in Between

As foreshadowed in our most recent post, I thought I’d provide an update on some of my recent astronomy related goings-on. Since March, I’ve been pretty busy with the first few courses of my program as well as trying to fit in some time to work on a bit of data in regard to what will eventually be my thesis. My course work thus far has involved assignments, preparing/giving three 45-minute seminar talks and now the focus is mostly on completing two significant research projects. Two of my talks have been on summarizing recent major review papers. The first was on the idea of a universal stellar initial mass function (don’t ask…you don’t want to know), and the second was a review of what the community knows about the formation of massive young star clusters, the sort that I will be studying in detail for the next few years. The other talk was a lecture to my stellar variability class on various techniques of determining pulsational periods of variable stars…thrilling I know.

As far as the thesis goes, thus far there is exactly zero interesting information to report. Indeed, when time has permitted, I’ve just been trying to reduce some data taken of some large star clusters in the galaxy NGC 5128, or Centaurus A as it’s also called. Unfortunately, the most important task in astronomical observations, transforming what we get from telescopes into clean, usable data, is also one of the hardest, most frustrating and challenging parts. I’m hoping that after the semester is finished at the end of June, that I can work full-time on getting these spectra reduced so that I can move on to the fun part: analysis. In this case, I’ll be trying to measure what kind of chemical abundances are in the clusters, e.g. how much carbon, magnesium, calcium, iron, etc., the systems have. These measurements will tell me what kind of star formation has happened in the past, since all of those elements are created on different timescales by different types of stars. In the long-term, I’ll hopefully be creating some computer models that simulate how such massive groups of stars evolve, and most importantly, form. The observed measurements, combined with those of clusters in other galaxies (and galaxy clusters) will serve as a good test to see if my models may actually be accurate representations of how these structures form.

I’m also working on two other research projects as part of this semester’s courses. For my extra-galactic course, I’m working with two other students on collecting information on a large sample of galaxy clusters in order to compare to work that has previously been done. We’re still quite early in the project though, so I don’t have too much to say about it other than that. This project will be very challenging in that it involves a subject of astronomy that I’m not very familiar with, so it will be interesting to see how it develops.

My other project is being done as part of my stellar variability course. I’m working with another PhD student on this, and so far it is coming along very well! With fingers crossed, we’re hoping to complete a report that might be submitted for publication since the subject matter is quite contemporary. The object we are studying, NGC 6569, is similar to the objects that I’m studying in Centaurus A; it is a collection of a few hundred thousand stars called a globular cluster (GC), in the bulge of the Milky Way. Specifically what we are doing is searching for variable stars, i.e. stars that periodically get brighter and dimmer, and plotting how the stars’ brightnesses change over time. This GC is interesting in that the ‘metallicity’, or how much of the cluster’s stars are made of elements heavier than H or He, is quite high compared to other GCs. Some recent work has suggested that variable stars in other high-metallicity GCs seem to have longer periods, i.e. they take a longer time for their brightnesses to increase and fade, than the same types of variable stars found outside of clusters. It will be interesting to see what kind of results we get. Will they have longer periods, or will they be more in line with what is expected from other GCs? Will the results point toward a fundamentally different sub-class of this type of variable star? One way or another, hopefully we’ll end up with a report that will be interesting to the theorists who incorporate these observational constraints into their models. As well, since these types of variable stars are used as ‘standard candles’, which can be used to estimate distances, this kind of work may effect current distances estimates that have already been done. We’ve still got a lot of work to do, but things are looking promising so far. To bring this update to a close, I’ll just leave this here…

The globular cluster NGC 6569. I wish I could take credit for the gorgeous image, but this was made from our data by my partner. The one I made was nice, but not this nice!

-M

Batman, Son of God

Buenos noches, it’s Matt here.

Well it’s been quite the week in Santiago. My courses started on Monday, so it’s nice to finally be getting into something resembling a schedule. This semester I’ll be taking three courses and unfortunately, my nightmare became reality as my first class started on Monday morning when, due to being in the minority (i.e. I’m the only native English speaker in my class(es)), the lecture was given in Spanish. Sigh, it’s not really what I signed up for, but nothing worth doing is ever easy is it? Truth be told, I may actually have a distinct advantage since all the papers and presentations that we need to write/give are required to be in English. I’m also trying to look at the Spanish lectures as a positive in the sense that each 1h20m lecture provides a very immersive listening experience, so hopefully that will help my Spanish skills come along a little more quickly.

After emerging wide-eyed (and shaking a little…) from that first class, I had to go sign my ‘beca’ (scholarship) at the university’s headquarters, ‘Casa Central’, in the central area of the city. Late last week we’d been to the massive, castle-like building to find the office where I needed to enroll, so I thought I was in decent shape. For the beca, I simply needed to go to the fourth floor, sign the papers and I’d be on my way! Easy-peasy…or not. I entered the building, walked over the polished, marble-tiled floors and under the massive stone archways to ascend the white marble staircase that dominated my view. As soon as I attained the second level, the stairs ran out, giving way to another wide corridor adorned with very Pope-y looking statues every 5 metres or so. Glancing out over a railing that overlooked one of the many courtyards in the building I noticed that there was a problem. There are only two stories.

Rather than randomly searching the building, getting lost and probably ending up somewhere that I shouldn’t have been, I decided to backtrack and go down to the information desk where Nichol and I were helped by a wonderful Chilena (from her kindness and caring air, she must be a mother…and a really good one at that!) to see if I could get some help. I found the office, and just like that, there she was, smiling and waving me over for her to help me! I swear I saw a halo flash over her head at times. She thought that I was there to enroll, but eventually I was able to explain that I needed to find the fourth floor to sign my beca. So off we went, passing through the labyrinth of hallways in search of the fourth floor which even she wasn’t sure the location of! Regardless, we eventually made it, and after asking at three different offices for where to go we eventually arrived at a tiny desk at the very end of a long, narrow hallway where I quickly jotted my signature down where told to. Phew. At least that was done. When we got back downstairs, my caretaker looking sympathetically at me and just kept repeating ‘tranquilo, tranquilo’; I must have looked pretty frazzled. I definitely felt it.

On Tuesday I had to go back to Casa Central, but this time it was to enroll. In this case at least I knew where to go, and it started off well enough before deteriorating into a frustrating experience of getting into all sorts of lines. The overall process only involves 3 ‘pasos’, or steps. Step 1 was to sign an agreement, typical code-of conduct sorts of stuff, basically signing my soul to the Pope. The guy helping me directed me to a cashier line to pay a registration fee, which was easily paid with my credit card, before I signed the papers, was given a new set of papers and sent off to Step 2. Step 2 involved checking that all my contact information was correct, but it turned out that another fee had to be paid for my student card. So off I went back to the cashier to pay it.

Up until this point, all the lines had been small enough to not warrant mentioning, but as time went on, they became longer and longer. This visit to the cashier took about 10 minutes before getting to the front, where I was told pointedly that it’s cash or cheque only.

‘No visa?’ I asked.

‘No.’

I’m not really sure what changed in 15 minutes, but she explained that there was a cash machine around the corner, so off I went to go try my Canadian bank card for the first time. Here I found another line, but at least my bank card worked with only a small fee. Back to the cashier I went, where the line had at least doubled. At least 20 minutes later I’d finally gotten back to the front, paid the fee and made my way back to Step 2 where, you guessed it, a line had magically appeared where there was no line before. Sigh, another half hour or so before getting to the table, correcting my information and heading off to step 3. At least that was easy as it only involved getting my picture taken for my UC ID card. How/when I get the card is still unknown, but at this point I was exhausted and still had to get back to campus to attend class.

Since then, I’ve just been attending my classes and have been introduced to many of the astronomers that I will be working and collaborating with over the next several years. To this point, I can still say that I have not met an unfriendly astronomer (some are a little odd, but aren’t we all?). Every person in the department, as well as those from other universities all seem like great people and it’s pretty cool to be part of such an international atmosphere. As my courses and various projects progress, I’ll be sure to update my Astronomy Debris section with anything note-worthy that I’m working on, so stay tuned if you are interested! For now, enjoy this picture of ‘Bat-Cristo’, which greets everyone as they come to campus. Is it Christ, or is it Batman? You be the judge.

-M.

Bat-Cristo. First he catches the criminals, then he anoints them.

My Star-Called Life

Well, you seem to have accidentally clicked on a link that has brought you to a little page on my geeky astronomy work. Don’t worry, you’ll find that life will be a lot more interesting if you click that little ‘Back’ button in your web browser. What? You clicked on my astronomy link on purpose? Alright then, if you really need to get to sleep that badly then I suppose you can read on about my experiences in the exciting field of astrophysics, but consider this sufficient warning! 😉

My undergraduate research work was a hodge-podge of different astronomy subjects. I tried to spread my research experience between as many different areas as I could, though despite my best efforts some subjects such as star formation and exo-planets have still slipped through my grasp. My main research project was on investigating dynamical and chemical links between the largest star complexes found orbiting our Milky Way galaxy, and relatively newly discovered objects known as ‘ultra-compact dwarf galaxies’. Following this work up, I then assisted in analyzing data from one of the largest surveys of the Kuiper Belt conducted to date known as the Canada France Ecliptic Plane Survey. The Kuiper Belt is a collection of cold, icy debris leftover from the Solar System’s formation, and orbits the Sun beyond the planet Neptune. The main conclusion from my work (only a tiny part of the overall study) was that the ‘hot classical’ and ‘detached disk’ components may in fact be two sides of the same coin! A conclusion only an astronomer could love.

Switching gears a little, I then conducted a small research project involving the geriatric years of a star’s life by employing some really cool numerical simulations. By this, I mean I simulated (through the use of some way-cool code and a way-powerful computer) the life of a star not too unlike our Sun during its final death-throes, but before it casts off its outer layers to live out the rest of eternity as a white-dwarf star. Of course, if said white-dwarf star has a companion, then that’s a whole other story which (for now) I won’t get into. Finally, to pass the time (and to afford the odd food-pellet) during the last eight months before moving to Chile I helped with one last study measuring properties of several million galaxies based on something called ‘broad-band photometry’. The results of this work are still being put together by my last supervisor, but the final measurements will hopefully shed light on what kinds of progenitor stars (the aforementioned white dwarfs with companions) are behind a particular type of supernova known excitingly as ‘Type Ia’.

Now that I’ve started my doctoral work, things have come around full circle so that I may work once again with my first supervisor, Thomas. This means I will continue to study massive star clusters, whether they be the somewhat controversially named ultra-compact dwarf galaxies (controversial because we’re just not sure if they should be called galaxies), hot, bright and blue young clusters that have just recently formed, the tight former cores of dwarf galaxies that have been gravitationally stripped of their outer layers, or the ancient, quiescent globular cluster systems that quietly orbit around the Milky Way and (as far as we can tell) all other galaxies.

I’ll sporadically add to this section as note-worthy developments like data breakthroughs, finished papers, new proposals and such come around but it probably won’t be a daily thing. But if anyone has any questions, or if you find any of this even remotely interesting, please do comment! If there’s one thing astronomers love, it’s people that love astronomy!

-M