Hello all. Lately I've been doing my first ever bit of "real" astronomical research and I figured some of you guys might be interested in it.
At my school the seniors are kicked out after AP exams are done to work on their senior projects, which are essentially anything you want to do provided you do 40 hours of it. For my project I called up the one astronomer I know down at the University of Pittsburgh and asked if I could do a project down there. She was nice and said yes.
My first day was Tuesday, I spent the time trying to figure out how UNIX and IRAF works, or at least making a noble attempt (I'd worked a little with the stuff before but nothing really). This all in all culminated yesterday when, after trying to play around with an image and failing spectacularly, it took two grad students a half hour to figure out what I had done and undo it.
Apparently if you are capable of disabling a computer to that extent you are capable of analyzing spectra. So I was given a spectrum of some quasar observed the previous week and given the lovely task of analyzing it. This was, for the record, along with the words "no one's really looked at this quasar before so you'll be the first human being to ever examine it." I just kind of gave a blank look and said "ok" because I couldn't think of much else to say to that!
So today I spent my time working on that trying to figure out the redshift of the quasar and the dust in front of the quasar causing absorption lines. It's rather interesting that I didn't have any major computer code malfunctions today- a minor miracle because I think I was starting to irritate a few grad students working around me. Based on the redshift I calculated (and I calculated right apparently, yay!) the quasar is about 9 billion light years away which REALLY blows my mind.
I started working through the elements seen in the spectra earlier today as well. So far there's been some Aluminum, Zinc, Iron, and a touch of Chromium. There's also a rare Fe II line that shouldn't really be there (some lines appear more often then others, this particular one is a few hundred or so times rarer then the others observed) so that was rather interesting.
So up to date that is my senior project, which is utterly nothing like most people's senior projects but I happen to think is the coolest thing ever. If anyone is at all interested I'm still working there next week so I can post my thoughts on that.
And with that I'd like to say working in the "Dupartmint of Fizzix and Astrolugy" is really fun and anyone who gets the chance should not pass it up!

__________________
Yes, I have a life. It's quite different from yours.

Well DUH! I think anyone on this board could have told you THAT!! :-p
Yea, i remember last year before astronomy camp i was planning to try to get spectra of the blazar that i was observing. that would have been really fun and interesting, unfortunatly, due to cirucumstances beyond our control that didn't happen. thankfully i never had to deal with UNIX or IRAF becuase i probably wouldn't have gotten much done and my advisor REALLY would have killed me! mmm...DOS...fun.... Hey, how bout in June we see if Don or Eric or someone show us a bit more UNIX (or, if you've figured it out by then, you could show me )
anyways, have fun!
I want to know what happens!!

__________________
Cold be hand and heart and bone
Cold be travellers far from home
They do not see what lies ahead
When sun has failed and moon is dead

Wait, you mean IRAF works?!? I'm still unconvinced that it's not simply some sort of sadistic prank that UNIX users and astro grads play on unsuspecting undergrads who grew up in a Windows environment...

__________________
"I'm making wheatloaf. It's like meatloaf, only with wheat"
"Isn't that just...bread?"

Does it make you feel any better to contemplate how those of us who grew up with IRAF in Unix and are fairly proficient at them feel when confronted with the, umm, different way everything works (sort of) under Windows? I always feel as if I'm not really talking to the computer. And my brian is completely wrong for dealing with a Mac. Now, SGIs are the way things should have gone...

Just curious...is it an SDSS quasar? U of Pittsburgh is a participating institution in the SDSS.

I worked at Fermilab on the SDSS in the 2001-2002 school year (teacher fellowship) so I know full well the frustrations of that type of research. I can't count the numbers of times I gummed up the works by putting stuff on the wrong disk and filling it up while I was there...they were very patient with me

I spent last summer at the National Radio Astronomy Observatory in Green Bank. I think that AIPS++ has to be competetive with IRAF in terms of jokes played on Windows users! Boy, what a pain that one is!

Rob

__________________
"Crackpot theories 1 : Regular theories a billion." Fry

Hale_Bopp and Andromeda,
out of curiousity, do either of you guys know Julia Thompson? she's at the unviersity of pitts. astro and physics dept, i do believe. Last summer she did a Research Experience for Teachers where I was working (quite obviously i wasn't one of the teachers but we all worked in the same room). I remember hearing the teachers mention Fermilab a few times, just wondering if you'd done the same thing they were doing?

__________________
Cold be hand and heart and bone
Cold be travellers far from home
They do not see what lies ahead
When sun has failed and moon is dead

Well, I don't know about the others, Andromeda, but I"M impressed! Rather beats my son's project, determining the periods of the Galilean moons.

But then, he's still a freshman.

__________________
If they can get you asking the wrong questions, they don't have to worry about the answers.

Oh, I'm thuroughly impressed. Don't get me wrong. I have the utmost respect for anyone willing to learn IRAF on their own. Or with help. In fact, if you know how to use IRAF, you're practically my god. All I've ever been able to manage is to launch ds9, and getting the urge to stab random strangers.

__________________
"I'm making wheatloaf. It's like meatloaf, only with wheat"
"Isn't that just...bread?"

There's a reason I call it IRALF, or IBARF. :-) I prefer IDL.

Analyzing quasar spectrum is a major pain due to the zillions of absorption lines, so that's pretty good work. Even with software, getting the redshift can be hard. We did it with active galaxies in the STIS spectra, but it wasn't hard-- if you saw two lines, you assumed one was H-alpha and the other was OII. It worked out pretty well.

So, some of you have observed blazars, eh? I have some involvement with that now! I'll be giving a talk on that project at a Society for Astronomical Sciences meeting next week!

Anyway, good for you! You done good.

I am major league impressed. I didn't do anything within a lightyear of that cool in high school. Heck, I didn't start on research projects till my junior year in college. I hope you have a blast.

__________________
At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009
All moderation in purple

No, I haven't met her. Dan VanDenBerk, now at U of Pittsburgh, was at Fermilab while I was there. The Fermilab gig was a year long teacher fellowship as opposed to a summer RET.

The NRAO position last summer was an RET.

Sounds like you are doing some great work, Andromeda. When you get to college, be sure to keep tabs on opportunities in the Research Experience for Undergraduates program. It provides summer research at various sites and in various disciplines for undergrad students. Check it out at http://www.nsf.gov/home/crssprgm/reu/start.htm

Rob

__________________
"Crackpot theories 1 : Regular theories a billion." Fry

I agree. I was just re-reading a year-old article in Nature (May 1, 2003) about a quasar at z=2.701 that was in line with a damped Lyman alpha galaxy at z=2.62, so the absorption lines caused by the galaxy showed what elements were present in that galaxy. I guess this was publishable because they found approximately 25 elements, including a number of heavy elements such as zinc and germanium. The presence of these elements, particularly those heavier than iron, in such a young galaxy was termed "striking." John Cowan of the U. of Oklahoma, who summarized the paper, said "Their work opens a new window on the early formation of elements and stars in the Universe." Very cool stuff.

__________________
Everyone is entitled to his own opinion, but not his own facts.

Maybe. The thing is a lot of people come through the astro computing lab looking for someone and start up conversations I end up getting drawn into. They all seem to know who I am and assume I know who they are (why I've no idea) and I've gotta admit most of the time I'm too shy to ask. ops:
Yes it is an SDSS quasar. It was supposedly observed last week by a grad student at the MMT. I don't know the official name of it, however, because I might be tempted to look into what's known about it and such. So I only find that out at the end.

As for what happened yesterday- I finished up the spectrum, the only really new stuff worth mentioning is some Fe I and Mangenese. Then I cleaned up the bad pixels and such and tried to print only to discover it wouldn't. So another one of those "grad students figuring out what the high school kid" moments happened, this time only to find that it wasn't my fault (yay!) because the printers were all off line due to renovation. This led to the evolution of my new theory that every institution in the known universe is perpetually plagued by printer problems and if I was actually smart I would find work as a printer-fixer person.
The day ended early because my boyfriend's prom was later that day and I had to get my hair done. A lot of people ended up doing a double take on this news because we were sitting in the grad student lounge at the time and I don't think that's something you normally hear there! :wink:

__________________
Yes, I have a life. It's quite different from yours.

Ah, even the Bad One sounds like a young grasshopper. If y'all had ever worked with IPPS, which is what IRAF replaced in 1985, we wouldn't hear so much grousing. The I stood for interactive - as in every command and parameter had to be entered when prompted, no scripting. Ran in one room with three graphics terminals and a single image display, located directly below the CDC 7600 machine so they could put a custom "high-speed" link. Didn't like the order of steps the programmer had imposed on reduction? Tough.

Still, it had one very cool feature - the IIS image display had three image planes which could be mapped to RGB, and each plane had actual physical knobs you could turn to change the brightness and contrast on the fly. Getting decent 3-color composites for me still hasn't gotten quite as fast.

And one thing I still haven't seen competition for IRAF in is in reduction of two-dimensional spectra, long slit or multi-object. Now once it's extracted to one dimension or rectified to pure wavelength/position/intensity, I often bolt to IDL as fast as the next grumpy astronomer... And for a lot of routine imaging tasks, I've stared using Axiom Research's (i.e. Mike Newberry's) Mira package running on my laptop (the one I bought with proceeds from playing trombone in a ballroom dance band - does that jeopardize my professional status?). Image alignment, combination, and aperture photometry are a lot more convenient than in other things I've tried. Well, except that I seem to have an uncanny ability to find data sets which uncover hitherto invisible bugs, but Mike has been stunningly fast in finding the problem and updating the software.

Mind you, I need IRAF, STSDAS, IDL, and (gasp) FORTRAN on a pretty much daily basis... and spend a fair amount of time trying to help grad students and summer research folks over the vertical part of the learning curve. If anybody needs it, I can make a PDF of my instructions for reducing a 2D galaxy spectrum in IRAF (great, now he tells us!).

Is this going to turn into one of these "Well, when I was a grad student, I had to walk twenty miles uphill to the computer lab barefoot, enter the data by beating on the side of the computer with a two-by-four, get the output by having it tattooed on my stomach with red-hot needles - and I was grateful!" threads?

__________________
Everything I need to know I learned through Googling.

Well, not if I can help it. I won't post any scans of that old roll of printed grocery tape with photon counts from prime-focus scanner operated from the platform riding up and down the dome slit opening at the Crossley telescope. (but the trasformation [i]has[/] been remarkable considering that some of us aren't all that old)

On the other hand, anyone who has a viable idea on how to bring data-reduction software into the 21st century is much more than welcome to present a plan here...

What do you mean by data reduction software?

Software that reduces raw data down to something comprehendable?

__________________
"I'm making wheatloaf. It's like meatloaf, only with wheat"
"Isn't that just...bread?"

Basically, at least to remove the instrumental and atmospheric signature, and present results in as nearly physical units as possible. For example, beginning with a set of CCD frames containing a possib ly distorted registration of a galaxy spectrum in counts per exposure, yield a corrected array of intensity in energy units per wavelength as a function of position in arcseconds, with foreground night-sky emission removed as well as defects of the CCD. Optionally, measuring a velocity and linewidth profile along the slit tracking statistical errors. Another example would be taking a set of CCD images, normalizing from the median of stars to remove atmospheric changes, and doing time-series photometry of stars within the series. As another poster said - any of the processes going from raw data to physically interpretable results.

This is what most of the time of many practicing astronomers gets taken up with, which the practically religious obsession in discussions of particular platforms or approaches.

Why do you say it must be brought into the 21st century?

Having only been exposed to IRAF, I can only speak about it... But the software is possibly the least user friendly thing avaliable for any OS. It feels like it was written before keyboards had backspace keys... More importantly, it seems as if it comes from an era when most serious computer users stared at a black screen for hours on end. Many people these days are unfimilar with even DOS, so even the lack of the most basic of GUIs makes learning the softwear a difficult and confusing process.

__________________
"I'm making wheatloaf. It's like meatloaf, only with wheat"
"Isn't that just...bread?"

Heh. Do/did you use STIS? I worked with a group at Goddard, and we designed software for (STIS-specific) long slit, echelle, and other 2D spectral extraction. I didn't design much of it (a real programmer did ) but I did a lot of work into calibration and such. STScI based their reduction packages on what we wrote. 8)

i've only had the...er..."pleasure" of being left alone to fend for myself at a computer with IRAF once. Last summer my boss was showing me the very basics of IRAF, we were trying to flat field an image in IRAF because we weren't sure if our image was messed up or if the program we were using was messed up. So he left me w/ that and after I figured out I had no idea what I was doing i just played around with the image a bit and spent the remainder of the day renaming files (mine of course, nothing important either, we just deleted them afterwards) :-D fun right? thank god for Photom II!

__________________
Cold be hand and heart and bone
Cold be travellers far from home
They do not see what lies ahead
When sun has failed and moon is dead

Interesting as this conversation is, who wants to hear the next installment in Andromeda's astronomical adventures? Hmmm, that sounds like a cheesy Saturday morning cartoon series... quick, I need a theme song! :wink:
But first, it might be good to have a quick description of terms for people who know as much as I knew before I started this little odyssey-
SDSS- Sloan Digital Sky Survey, an attempt to have redshifts, spectra, and all sorts of stuff like that for objects in a quarter of the sky (about 100 million of them).
quasar absorption lines- caused by dust from a galaxy in front of the quasar, they make a trough in part of the spectrum
equivalent width, aka eqw- the area under the spike seen in a spectrum. .5 seems to be about average for an element as far as quasars go.
Ok, on to the cool stuff! While I was patiently labeling a printout of the spectrum (the printers finally came back online) the person I'm working under asked me to come talk to her. She'd seen the spectrum last Friday and had an interesting bit of news to tell me about it. The zinc I mentioned a few days ago had an equivalent width greater then 2, for the record, and since I've no experience in the field I didn't know that was odd. But apparently zinc is supposed to be incredibly rare being a metal and all and apparently my quasar is the first ever observed to have a zinc line like that!
Thank goodness I was sitting down at the time because that was quite a jolt. Because let's face it, eighteen year old kids without high school diplomas yet are not the ones who tend to discover odd spectrum lines, especially ones that really shouldn't be there. Just to make certain of things I asked and, no, I did not mess up during the analysis. The odd zinc spike really does exist.
Unfortunately the end of my day came too early and I had to leave on time to pick my brother up from school (if you get to drive the car you have to pick up siblings who do not get to drive the car). So, if you want to get closer to a conclusion, tune in tomorrow for the next installment of "Andromeda's Astronomical Adventures: the Case of the Zinc Absorption Line!" 8)

__________________
Yes, I have a life. It's quite different from yours.

Hey, it's tomorrow already! We're waiting...

Yes, this is much more interesting! While we're all waiting, allow me to heighten the suspense for those who don't follow high-redshift cosmic chemistry.

Many people find quasars as interesting for what the illuimnate as for their intrinsic properties. Since we can see them so far away, their light often passes through gas on the outskirts of galaxies which are too dikm for us to analyze by their own light. Here's an example of such a galaxy first seen from its redshifted 21-cm hydrogen absorption which turned up in Hubble images:



(See http://www.astr.ua.edu/keel/agn/3c196.html for details). Using these intervening absorption lines has allowed a look at the chemistry of galaxies whether they're easy to see or not. If our galaxy is typical, we expect to see similar histories of the production of heavy elements from stars in our galaxy, from ages of old stars, and from the gas abundances in other galaxies as we go out in redshift. There are two ways one might see a strong zinc absorption line, both interesting but in rather different ways. It might mean that the quasar light goes through a very gas-rich part f the galaxy without too much being lost to dust - in which case this will be a chance to learn about additional elements that are normally too weak to measure. If it's only zinc which is enhanced among the observed elements, that's even more interesting, suggesting that something is different about this galaxy or the piece of it that we're seeing.

Zinc already stretched the amount of this metal predicted from explosions of massive stars (from a recent paper by Prochaska and company), so galaxies withg even more zinc are telling us about something we don't understand as well as we thought. And that's how science makes progress.

So - come on, Andromeda321, tell us more!

[-X Hey! Cut her some slack!

Just how much bleeding edge astronomical research were you doing when you were 18? :roll:

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Technically it was the next day, we just want our Andromeda fix is all. :wink:
Plus that post was made at ~0700 their time, I believe I can safely say it was a joke.

__________________
Calvin: Sometimes when I'm talking, my words can't keep up with my thoughts. I wonder why we think faster than we speak.
Hobbes: Probably so we can think twice.

~Calvin & Hobbes~

Ok, next installment! Sorry to say this one isn't as exciting, however. I woke up today with a splitting headache (odd because I never have them) so I went in later then normal. Then I spent the time there trying to get rid of the emission/absorption lines in the spectrum because we want to divide that by the "ideal quasar spectrum." This way all you would have left behind would be the spectrum of the dust and you could see what the situation is with the galaxy (ie lots of faint lines or whatever).
It didn't help matters when halfway through I kinda messed up the spectrum. So I had to start over again, which was rather frustrating because there are so many stupid lines.
So I'll finish that up tomorrow and hopefully figure out how to divide out the ideal spectrum. Wish me luck, I think I'll need it!

__________________
Yes, I have a life. It's quite different from yours.

You're doing just fine on your own, but if it makes you feel better I certainly wish you the best of luck. Oh and "May the Schwartz be with you." :wink:

I can't wait to see the next edition of our Andromeda drama! You get 'em. As the father of 2 young girls it thrills me to see a young woman as smart and dedicated as yourself applying your knowldege. =D> =D> =D>

__________________
Calvin: Sometimes when I'm talking, my words can't keep up with my thoughts. I wonder why we think faster than we speak.
Hobbes: Probably so we can think twice.

~Calvin & Hobbes~