Week and Weekend 2

So, it's the beginning of week three, and my computer is still doing all the work for me. It's now griding all the data into 8 data cubes. Basically this means it's taking all the data and dividing it into 8 boxes. The data has three type of information in it: right ascension, declination, and the frequency of the waves. Right ascension and declination give the coordinates in the sky, like latitude and longitude on Earth and the frequency can be converted into a velocity. All the data has been taken of the emission produced by the hyperfine spin-switch of neutral hydroden. This particular energy level switch gives off electromagnetic waves of 21 cm or 1420 MHz. However, since this emission is coming from all different sources outside our galaxy and due to the expansion of the universe, which causes the wavelengths of the light to be redshifted, we detect the neutral hydrogen emission at wavelengths different from 1420 MHz when it comes from outside our galaxy. The amount of redshift in the wavelength (which goes hand-in-hand with a change in frequency). Got all that?

So, what the program is doing, is cutting the data into 8 sections, as I said before. Then, it's splitting each of these sections into velocity ranges. What we end up with is what's called a data cube. It's like a 3-D cube of data the computer creates. On two of the axis, the computer puts right ascension and declination. That tells you where in our sky the data was taken from. Then, on the third axis, the computer puts the velocity. We can then manuever the cube around to look at it from various angles.

While the computer is doing all this, I'm reading difficult physics papers, trying to understand how all this works and what all we can find out from this sort of survey. Most of the papers are written for graduate students, so they're quite a challenge for me. Fortunately, my mentor is very patient and willing to explain anything I don't understand until I do. :)

Though the week days are still kind of dull, I'm having a wonderful time on the weekends. This past weekend we went to a small town that was once a US airforce base, but is now just a nice small town, sitll with lots of reminders of what it once was, of course. We were lucky to have a local guide all weekend; an retired man who used to work at the observatory, but now lives in the small town, showed us all around. On Saturday we went biking all day, all around the town and countryside near the ocean. We also went snorkeling, which was a lot of fun.

Saturday night we celebrated the beginning of St. John the Baptist's day, which was Sunday. St. John is the patron saint of PR (the island was once named for him). The celebration starts at midnight Saturday night. It's tradition to walk into the ocean and fall backwards into it 3 (or 9) times (the number depends on who you ask). It's supposed to be for good luck, though no one seems to know why. Our guide's next door neighbor took us to the beach to participate. We were pretty tired after biking all day thought so we didn't stay very long after midnight to see what other things were going on. I don't imagine we missed much. It looked like it would have just been more drinking and dancing by the Puerto Ricans and then a horrible traffic jam to get away from the beach. We fortunately missed that!

On Sunday our friendly guide gave us a tour around the neighboring town and the beaches. We spent the remaining part of the afternoon on the beach, snorkeling, reading, and just generally relaxing.

Now I'm back at the observatory. I'm hoping the program will be done with the 8 data cubes by Wednesday morning so I can start the next step of the process. I fear it will be more processing, which means I'll continue to read physics. Oh well. It's all part of the process, so I guess I'm learning how it all works. At least I really like my advisor. He's Armenian but grew up in Syria. Last week he gave me a mini lesson on Middle Eastern history concerning Armenia. It was interesting!