Grad Life: The Target Incident

Posted by barb on Jun 1, 2004 in Thesis/Grad Life

The “Target Incident” is perhaps my quintessential grad school money experience. I’ll start by detailing my monthly budget — this will highlight why money was my constant concern (making it difficult to to concentrate on other things).

In New Mexico, I lived in a three-bedroom house, ostensibly with two roommates — one person for each room. However, both of my roommates had significant others who essentially lived with us, and the brother of the primary renter came down to live with us during the week (he lived and worked in Albuquerque on the weekends). So, in reality there were about six people living in the house at most times. I was tired of living with people.

When I moved to Maryland, I decided that I would get a place on my own. Afterall, I was 27 and it seemed time to try my hand at being alone (well, alone with my two cats). Also, since I had two cats, I wanted a one bedroom apartment rather than an efficiency, so the cats would have some room.

The rent for my apartment was $635 per month. My take-home pay from my fellowship was about $1000 per month. That left $365 to live on. Oh, but I needed to pay out $125 to my credit cards just to cover the finance charges. And I had the $50 phone bill, a $45 cable bill (that was probably a mistake), and $20 to keep gas in my car. That left $125 for everything else — cat food and litter, groceries, necessary-items, and any surprises that might come up. Needless to say, the budget was a bit stretched.

So, one December I found myself at Target picking up essentials — cat food and litter, toothpaste, toilet paper, deoderant, tampons, contact juice, and paper towels.

On my way around the back of the store, I saw a display of Christmas table clothes. I stopped to see what they had, and found the cutest vinyl cloth I’ve ever seen. It had little santas, angels, candy canes and reindeer on a green background. I think it was the reindeer that did it for me — I love reindeer decorations. I so wanted that table cloth. I knew that I couldn’t afford it, but decided to look at the price anyway.


Less that $3. I sat and debated for a bit. I looked at the contents of my cart, and thought about the money I had in the bank and the one measly paycheck I’d be getting before my trip home. That paycheck had to pay a few bills as well as a few meals out when I went to visit friends in Minnesota. Plus I’d already decided that I couldn’t get a Toys-For-Tots toy. Nor could I get the cats any Christmas presents. There was no way I could justify a $3 table cloth for myself.

But it was only $3. My god, how could I not find $3 in the budget.

I debated internally for several minutes before replacing the table cloth on the display and hurrying to the checkout. $3. I was nearly in tears as I checked out and brought my purchases to the car.

I realize, and even at the time I realized, that it was a silly thing to get upset over. But to not be able to pull even $3 out of the budget seemed a ridiculous and depressing thing.

The story does have a happy ending, though. I happened to talk with my Mom the next day (or maybe later that evening), and I mentioned the incident, trying to make it humorous but not succeeding. She ended up telling my Dad, and he Fed-Exed me a check for $50, telling me to just have fun with it. I bought my Toys-For-Tots toy. I bought the cats a new round “cave.” And, yes, I bought that $3 table cloth, which I displayed until I got rid of my round kitchen table two years ago.

* Some people might not worry too much about a Toys-For-Tots toy, but I had a nephew who died from SIDS at 4 months 21 day old. Since we lost him, I have been buying toys for TFT each year for a boy who would have been Tyler’s age that year. It’s my way of honoring his memory and hopefully bringing a little joy to a child.


Grad Life: Intro

Posted by barb on Jun 1, 2004 in Thesis/Grad Life

For the past several years, I’ve looked at myself as a recovering grad student. While I am a grad student again, the situation is quite different from my life of 1998-2000, and I don’t think that any further damage is being done by my half-time status.

Somehow, during those years, I lost parts of myself that I really liked and respected. By 2000 I had become more relcusive and shy that I was when I started grad school. I also found that while I was a strong student, in my personal life I became less independent — I no longer enjoyed doing anything outside my apartment by myself. I wouldn’t just go off to a play I wanted to see even if I couldn’t find a friend to go with me. I wouldn’t try a new restaurant if it meant I had to go alone. Pre-1998 I would do that.

Part of my recovery process has been to document both the good and the bad parts, and hopefully in the process I’ll recover part of what I feel I lost during those years. So far I’ve been doing this in a paper journal, but I’ve been lax about writing, so I hope that doing it here will encourage me to write more and more often.


ASCA results and re-directing my efforts

Posted by barb on May 26, 2004 in Thesis/Grad Life

Last week I met with Kim about the Constellation-X web pages. I also brought her a preview of my ASCA results.

The point of running the ASCA data was to see if we could see the same structure in it’s data as the XTE data. If we could, it would be good confirmation that the structure is real rather than instrumentational. Unfortuantely, the ASCA data do not show the effect. However, after talking with Kim, we decided that it’s entirely possible that ASCA does not have enough response in the higher energeis to actually show the structure. To this end, I’m going to find average count rates for the various energy ranges for each instrument, and perhaps show statistically that ASCA can’t detect the structure.

Kim also suggested picking another type of source and use it as a control source. Ideally a cluster of galaxies would work, but unfortunately there aren’t many repeat observations of clusters in the XTE archive. Instead, I’m going to look at the Crab data spanning the same years as the MCG -6-30-15 data. If the structure is real, i.e. inherent to MCG -6-30-15, then we should not see it in the Crab data. However, if the structure is instrumentational, we will see it in the Crab data. My only concern is that the Crab is a “bright” source; whereas MCG -6-30-15 is a “faint” source. Different background models are used for extracting the background spectra and lightcurves for “bright” versus “faint” sources. Someone might argue that the structure is due to background modelling — not sure if that holds water, but might need to investigate.


ASCA data

Posted by barb on May 5, 2004 in Thesis/Grad Life

To track whether or not the effect I’ve been seeing with MCG -6-30-15 is real, my advisors suggested that I delve into ASCA data. The hope was that I could use data directly from the Tartarus Database of AGN observations from ASCA. However, I’m looking at the data in different energy bands — in theory, I could use the extracted spectra from Tartarus, but it would be using the data in a different way that I’ve been using it with the XTE data.

The upshot is that yesterday and today I’ve been delving into the ASCA data iteself. I needed to reinstall HEASoft software package to deal with a bug in XSelect — a tool I need in order to extract spectra and light curves from the ASCA data. In addition, I needed to find a version of SAOimage to run on Mac 0SX (fortunately HEASARC had one I could just download in pop into the appropriate directory).

I haven’t dealt with many data sources other than those from XTE. ASCA is an imaging telescope, unlike XTE, so it’s a bit different to work with. Rather than just using the raw data files and scripts, I need to go into the extracted images and tell the scripts where in the image I want the lightcurves and spectra extracted from. Honestly, it’s a lot easier than the XTE data, at least so far, presuming that I’m doing it right.


Thesis Meeting

Posted by barb on Apr 23, 2004 in Thesis/Grad Life

I met with Kim and Chris again this afternoon. We are still trying to figure out if the weirdness I saw in the data is real or just an effect of instrument gain changes. The problem is that the XTE PCA is quite susceptible to gain changes, and the background may not be modelled properly for all of my data. The question, then, is whether or not the effect that we’re seeing could arise from gain changes.

I’m going to attack the problem from two tracks in the coming weeks. First I’m going to persue the veracity of the weirdness by looking up data on this source from other X-ray missions, specifically ASCA and XMM. Second, I’m going to assume that the weirdness is real and make some plots to show if and where changes in the spectrum reflect the weirdness.


Meeting with Kim and Chris

Posted by barb on Mar 19, 2004 in Thesis/Grad Life

I shared results from my fits to spectra for MCG-6-30-15, IC4329A, and PG0052+251. But more exciting than that is a re-presentation of some data I shared at our last meeting. I shouldn’t really say much other than that we think we’re seeing behavior that no one has seen before in AGN. I’ve got a list of things to do, and then we’re going to submit those results as a letter to ApJ.



Meeting with Kim and Chris

Posted by barb on Feb 6, 2004 in Thesis/Grad Life

I met with Kim and Chris today, finally. Unfortunately MCG -6-30-15 was not quite done (273 out of 290 spectra were fit), but I could still show them the majority of my results. MCG -6 continues to be an enigma, though that’s nothing new. It’s been well studied over the years, and it has been shown to display unusual behavior.

The good news is that we are starting to be confident in the results from my pipeline, so I am going to go ahead and fit more sources over the next month. I’m also continuing a bit more with MCG -6, including doing some hardness ratios and color-color plots. I also need to write scripts to do flux-resolved spectra to compare our results from time-resolved spectra. We suspect that the results will be different, since flux-resolved spectra may smear out any short time scale changes (i.e. changes on the order of a day to a week).


Paper Published!

Posted by barb on Feb 3, 2004 in Thesis/Grad Life

Check out the Table of Contents for the February 1, 2004 issue of ApJ!

If you scroll down to the article on page 771, you’ll see why I’m so excited.


Thesis Meeting

Posted by barb on Dec 18, 2003 in Thesis/Grad Life

I’ve still been going around the block on my MCG -6-30-15 fits. I was at least able to reproduce the published results, which had been a goal for last month, but this still doesn’t explain what’s going on. Basically, we are finding that cutting spectra one way produces one set of results while cutting them a different way produces different results. This might mean that the published method is not the right way to do things. However, it might also mean that there is not enough signal in my method to get good results.

My next step will be to fit the full MCG -6-30-15 XTE data set — this is nearly 7 years of data, and will take a lot of computer time. Hopefully I can get it running before the holidays, and just leave it going uninterrupted for that week (though there is always the possibility of a power glitch or infinite loop to mess things up). Kim thinks it might be interesting to plot the results in a way that we can see the time evolution of some of the relationships, so I’m going to look into using numbers as plot symbols in ppgplot. I’m also going to look into doing color-color diagrams (or hardness ratios) of the data to see if there is some way to see where the changes are really occurring. That will require writing some new code for the pipeline.


Thesis Meeting

Posted by barb on Nov 7, 2003 in Thesis/Grad Life

I was getting frustrated with the data I’ve been fitting, so it was good to finally meet with them to talk about it. The goal for the past month was to take a previously published data set to compare the results I get from the automated pipeline to the published results. We, of course, were hoping to find that the pipeline was getting comparable results, because that would bolster my pipeline.

Instead, I found that my data showed the exact opposite trend as the published data. I did everything I could think of to re-analyze and re-fit the data to see if I could extract their trends. In the end, my data just doesn’t show the same trend. This is a potentially interesting and very exciting result. One difference between the way I’m analyzing the data and they way they are is that all the points in my spectra are temporally adjacent, whereas they extract all points in the observation according to flux level with no attempt to keep temporally adjacent points together. What we’re thinking this might do is smear out the time scales of change in some of the parameters. This may produce spurious relationships between parameters that can’t really show the true picture of variability in the source.

I’ll be testing this theory by re-extracting my data using their technique. If I find their same trends, that will be a strong case that their work was not the right way to do things. If I find something else, then we’ll have to look more closely at my work to see what’s going on.

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