Newbie introduction...

For the CASA documentation?

Check.

You almost feel sorry for these people, don't you? Isn't it good that it's not YOUR job to ply me with things to do?

New Assignments

1) write 4-page introductory introduction to CASA. (The current introduction runs 60 pages. It's more of an... overview... than an introduction!)

2) build a few mockups of what a status and forecast page might look like, for all the poor schlubs who are sitting at their home Universities, and starting to be terrified that they won't know what to do with the data coming out of the correlator.

3) a few minor adjustments to the spreadsheet.

Apparently, this is supposed to take me the remaining ~8 weeks of my time here.

So I think I'll write a grant proposal. ; )

One thing I've learned is that spending time at a 4-year, underfunded, teaching University makes you really, really efficient about using your time. And spending time at a research institution encourages you to think about things. That's not meant to be a criticism. It's not bad, it's just different. They have a tendency to overthink, and I have a tendency to slap things together and call it good. It takes all kinds to make the world go 'round...

The weird square thingy...

Right. So finally I asked somebody about the weird square thingy. We discussed it, and agreed it couldn't be a problem with clean. So he suggested I go back to the visibilities.

So I went back to the U-V plane, to look at the data. Yup. There it is. A couple of U-V visibilities needed to be flagged. No more weird square in two channels.

But all of this just points out that we darn well better invent autoflagging before the new correlator comes completely on line. It's one thing to look at data from 256 channels. It's a completely other thing to look at data from 100,000 channels. No one will use the thing if they have to find 'bad' data by hand.

So that's my next task. To figure out... wait for it... where the group is with the autoflagging. Because no one can remember.

Wait...

what was I doing?

Where's my pencil?

What does this cryptic note mean: 'vague recollections of the weird square thingy'?

How do I log in to my computer again?

Password... password... password... I'm sure I had one.

D'oh. Return from very busy time away. Man. I'm sure there was a plan around here someplace.

Some Perspective

It's pretty hard, right at the moment, to keep everything in perspective. Between all of our own personal dramas, the local dramas that come with the tragically bizarre collapse of the economy, and the global dramas that come from not being able to keep our grubby mitts off yesterday's sunshine, a person can get seriously overwhelmed.

But then, you get to see this.


Please allow me to interpret the sci-jarg. The dot in the middle of the left image is an optical image of a galaxy that formed very early in the Universe. How early? About 12.8 billion years ago. You are looking at it as it forms, because the light that left during formation is just now getting to us. Ok. Go away and think about that for a minute, because that should blow your mind right there.

Back? Ok. The image on the right is of the same object, in the radio. Specifically, you are looking at the light emitted from carbon monoxide (CO). Go away again, and ponder the existence of carbon monoxide, only 870 million years after the Big Bang. Need some help with the staggering-ness? C and O form in stars. The existence of CO means there were stars that lived AND died before this big cloud could form. AND the cloud had time to cool enough for the C and the O to get together and share some electrons over coffee and a biscuit. AND the cloud had time for gravity to begin to draw it together to form something new. 870 Myrs is not very long for all of that to happen! The first stars must have been very, very massive, and very, very short-lived in order to get all this done in that short time. So, go. Ponder.

Back? Ok. So now you have to think about this. You are looking at a supermassive black hole (some millions of times the mass of the sun), and a giant elliptical galaxy (trillions of times the mass of the sun, eventually forming trillions of stars) being 'born'---at the same time, in the place, very early in the history of the Universe. Staggeringly, this is exactly how we thought it should happen. Staggeringly, I can explain it to you. Staggeringly, you can understand. Score one for the teeny-tiny, microscopic gray matter connections inside your head.

One of the biggest comforts of being an astronomer is knowing that the vast majority of the Universe doesn't care about me. It just does what it does. It goes on in all its profligate excesses of space and time, and all its random happenstance, whether or not I'm paying any attention at all.

Another comfort is that I am paying attention. And my own little gray matter adds its little pieces to the puzzle, which are written down, and so will be remembered long after we've forgotten all this year's particular drama, and the last of yesterday's sunshine is all used up.

Surprise! A conference...

Well, other people knew about it, I'm sure...

There are ~95 people here for three days for a conference about the EVLA, and galaxy formation and evolution across all redshifts. (While this is not an area of special interest for me, personally, I can still learn a lot!)

I didn't have to plan. I didn't have to travel. I don't even have to present (which is good, because it was a surprise to me, and I'm not an expert in galaxies!!).

This is almost sinfully easy. Just sit there, and let the conferences come to you... Ahhh...

It's like 4th of July, for astronomers.

I finally figured out what was wrong with Lorant's maser data. The techs had reset an antenna position in the middle of the run. So 75% of the data was flagged on import. D'oh. So I fixed it, and re-calibrated.

Now, I have a little movie that goes through the image cube, from one end of the spectral window to the other. And when I watch the little movie, the masers light up and fade out sequentially. All over the spatial dimensions.

It's like itty-bitty, noiseless fireworks.

Just for me.

Back to work...

So, with all that election chaos and emotion, you might be under the impression that no work is getting done.

But you'd be wrong!

I've acquired data (from the archive) on six masering OH/IR stars.
I've duly calibrated and reduced spectral-line data on two of these objects. I actually did that twice, because:
I've found two more bugs in the CASA code, and reported them to those who can fix 'em.
And then I reported a bug that wasn't a bug. It was just me not understanding what the code did. Oops.
I've found several unhelpful error messages that need to be reworded so that novice users will know what they've done wrong.
I've re-organized the CASA spreadsheet o' tasks, so that everything is not priority 1. Scientists. Sheesh.
I've investigated Bugzilla, Mantis and a couple of other programs as a better way to report problems to the development team. This, by the way, is a priority 1 task in the spreadsheet... ; )

So, that's all good. Especially since spectral line data is big and slow, and cleaning it can take your computer as long as four hours. If you do it right. The first time. Which never happens. ; )

Oh, and I also created a sweet Google-docs worksheet for the environmental physics class, as part of the semester-long project students are going to be doing. During which, I learned about solar hot-water heater installations.

And I read the appalling and terrible (but well-written and vitally important) book 'The Weather Makers' by Tim Flannery. Yep. Sometimes there's nothing to do but lay on the sofa and cry for the golden toad (extinct) and the polar bear (soon to be so). So now I know a lot more about climate change. That'll be helpful, as soon as I can wrap my head around it.

I list this all here, because I was thinking that nothing was getting done, and it was depressing me. But now I can go back to work, mightily cheered up!

Odd. Tomorrow is Veteran's Day. It's an NRAO holiday. And we're supposed to actually stay home. On a holiday. What's up with that?

Never mind...

Weird results... still there.

Turns out that during the period of my observations, they had some trouble with the instrumentation labeling sources incorrectly. So my calibrator was called by the name of my target, and vice-versa. CASA, apparently, knew about this, but AIPS did not.

So when I went to look at my target in AIPS, it was a point source. Which it should have been, because it was actually the calibrator. And then my calibrator was extended. Which it should have been, because it was actually my target. Did you catch that?

Un-poof.

Totally, even sweeter astronomy...

So, of course, the second thing you do is go read IN DETAIL, every single paper that ever even mentioned the interesting source you've just taken a picture of. Including the theory papers. Buried in those theory papers, you find a reference to a Nature paper, that you didn't find before, for who knows what reason.

And in THAT paper, (in 2001), Miranda et al. report that the age of the photo-ionized inner region of the nebula, deep down in the round part, near the center, is 15 years*.

Not a typo.

15.

years.

This nebula transitioned from proto-planetary nebula to planetary nebula in 1985. That was the year I started high school. Wow. How fun is that?!

That's every reason to study these objects, right there. They change during your lifetime, which is extremely unusual for astronomy!

* How do they know? This is a 'dynamical age'. Basically, they measure the velocity of the outflowing ionized gas (using the Doppler Effect), measure the size of the region (which is where you are going to have errors, because the distances are usually poorly determined), and then you divide the size by the speed to get the age. (This is the same logic as saying that you traveled 60 miles at 30 miles per hour, so it took you two hours.)

Totally sweet radio astronomy...

Ok. So this is totally sweet. Look at those maps. Two maps of the same object at two different (but close together) radio wavelengths. It's a bipolar planetary. The primary emission at the central peak overlaps, as does the emission fAwesome!rom the bump to the west. The southeast lobe in the right-hand map is nearly mirror image of the northwest extended lobe+bump! This is really rare. We are seeing radio emission from the bipolar axes of the nebular outflow. What does it mean? It means that my little fishing expedition paid off, and we have an object that should be examined in LOTS more detail to look for magnetic fields! Sweet!

p.s. It's also fun that in the right image, there's a big Easter Island statue at the top. that's random... I'll have to look in the catalogs for a background object...