Friday, August 26, 2011

Day 37

Presentation day! I think it went really well and although I was extremely nervous all morning. Everyone else did really well too! We gave Joe, Bob and Bethany their gifts (a photo-shopped picture of all of us) as well as a lava-lamp for Bethany, which I think they will all enjoy! Afterwords we all stuck around and talked for awhile... and planned to go overnight laser-tagging and/or a concert at Darien lake sometime! Also, Jake took the astronomical imaging interns (me, evelyn, matt, alex and jason) out to lunch at applebees, which was fun! I'm sad the internship is over (but happy that the presentation is) because I am going to miss everyone :( and the free food too. This experience was amazing and one that I will never forget!

Day 36

Couldn't come into work today . . .spent the night practicing for tomorrow!

Day 35

Today I showed Joel and Rudy my power point and worked on some of their suggestions for improving it. I don't have much more to do with it though . . . except for practice! I can't come in to work tomorrow either, so I won't be able to practice with everyone else. I am kind nervous for this presentation!

Monday, August 22, 2011

Day 34

Today I came in again around four and showed Joe the rough draft of my powerpoint to make sure it ran well on his computer. Then I continued to work on it. Joel and Rudy gave me some good suggestions for a few of my slides but I still have to go through the whole thing with them. Rudy gave me a link to this website that makes a graph of the optimal viewing times of a star from a certain observatory. It says that it would be best to observe 2M1155-79 from Australia in March . . . but it could be possible as soon as December. Joel is hesitant to write a paper about this until we see if the star has Li absorption, which we will hopefully find out with the visible light spectrum.

Day 33

Today I got here around four in the afternoon and just worked on my powerpoint. I think it is coming along pretty well. I was too tired from soccer to stay for too long so I left around 6:30. I don't think I can make the "practice" presentation on Wednesday... which really worries me because I need all the practice I can get!

Thursday, August 18, 2011

Day 32

In the morning I wrote up a detailed summary of how I found the possible companion stars using Topcat. I also went through the process myself, using the mean proper motions, so I can have the exact results of what you get using them. I've already checked to make sure that the new stars that show up using the mean proper motions aren't emitting x-rays, but I wanted to have the correct lists on file anyways.

Today was the last day I could attend coffee time :( Starting tomorrow, I won't be able to come to work until around four because of double sessions of soccer try-outs. But the strawberry-smoothie I got today was amazing!

In the afternoon, Joel clarified a few background questions I had about companion stars and why they chose V4046 Sgr, MP Mus, T Cha, and TW Hya to study. It is because these stars are around 10 million years old and still have gas in their circumstellar disk, but are just starting to form planets. Usually, stars form planets and lose the gas in their circumstellar disks by 2 to 3 million years old. Therefore, there is a theory that these widely separated companion stars (like TWA 28) were once very close to, in this case, TW Hya, and prevented it from forming planets until now. I made a slide for this info in my powerpoint.

Things are looking good for 2M1155-79, the possible companion for T Cha. Rudy continues to analyze the spectrum and he found a small absorption which is good because that means the star doesn't have a disk (most companions don't). Joel is going to ask his friend in Australia if he will extract the spectrum using his telescope, so we can see if it has Li absorption (indication of a young star).

Wednesday, August 17, 2011

Day 31

Today in the morning I used Topcat again and re-did the search for companion stars to T Cha, and V4046 sgr, because their simbad PM's are significantly different from the mean of their PM's. This time, I matched the PPMXL and UCAC3 lists and then made two more columns on the matched table for the mean pmRA and pmDE. Then, I matched this with the 2mass catalog and limited the stars so that only stars with the mean of their PM's within 15 mas/yr of the binary star's mean PM. I didn't come up with any new star coordinates for T Cha, but I came up with a few for v4046 sgr. However, none are emitting x-rays . . .but it was worth going back to just check and make sure. Also, I finished putting the vectors to represent proper motions on the ds9 x-ray image of MP Mus and it's possible companions. For lunch we had free pizza and watched a movie about entrepreneurs.

In the afternoon, I began by going through Joel's email about how he calculated the bolometric luminosity of our unknown star, which we nicknamed 2M1155-79 (from its 2mass coordinates). The ratio of its x-ray luminosity to its bolometric luminosity is a little large, but not unreasonable, but Joel suspected that this was because the x-ray luminosity (from the spectral fit) was a bit too large. So Rudy re-did the spectral fit and found another x-ray luminosity that is smaller and more reasonable. Now we have officially discarded the RXJ star as a possible companion star and the only one we are still considering is this 2M1155-79. Joel said he might try and get someone to calculate proper motion themselves of T Cha and 2M1155-79 (by comparing recent images with images taken a long time ago). Meanwhile, my job is to write up a detailed summary of how I obtained the data (using Topcat) so that Joel can write a paper on this if he decides to. Also I need try and keep my powerpoint up to date, and decide if I want to present what I did with the planetary nebulae in the beginning of the summer or not . . so much to do, so little time!

Tuesday, August 16, 2011

Day 30

Today I got an email from Joel explaining that according to the Pre-MS catalog he found, T Cha and RX J1158.5-7913 (its possible companion) do not have similar proper motions. This was confusing because when I used Topcat to find the possible companions stars, I limited the results so that only stars with a proper motion of within 15 mas/yr of T Cha would be present. At first, I thought I had made a mistake using Topcat and this whole process of investigating RX J1158.5-7913 was a waste of time. But after doing a little investigating, I realized the problem is that some of the proper motions listed in the PPMXL, UCAC3, and Pre-MS catalogs as well as in Simbad are different! So now, we don't really know what source to trust. Instead, I am taking the mean of the PM's found for each star, regardless if it is emitting x-rays or not, and plotting them as vectors on the x-ray images using ds9. This way, we can visually compare the magnitude and angle of the proper motion vectors and decide which could be companion stars. Unfortunately, RX J1158.5-7913's mean PM is about half that of T-Cha's, which probably means that it is in the chamaeleon cloud . . .around 80 parsecs (one parsec= 3.26 light-years) behind T-Cha, and therefore is not a companion star. However, our 'unnamed' star is still in the running to be a companion, so the next step is to calculate the bolometric luminosity and compare that to the x-ray luminosity!

Day 29

The insight lab is now nearly empty because all of the REU students are gone. And there was no coffee-time :( I spent the morning working on my powerpoint and applying what I learned from the undergrad presentations last Friday to my own powerpoint. I went through what I've done with my presentation so far with Evelyn and she helped me identify what I need to improve on. For lunch, Bethany took us out to cross-roads with a prospective student who she was giving a tour too.

In the afternoon, I made of table of information (That Rudy got from the extracted spectra) about T Cha and it's two possible companions. It includes the extinction, temp in keV and MK, confidence range, observed flux, actual flux, distance in kpc and cm, and x-ray luminosity. Basically, we want the x-ray luminosity to be around 10^29 to 10^30 erg/s, because that means the star is more likely to be young. Using the spectra, we found that T-Cha's x-ray luminosity is 10^30 erg/s, RX J1158.5-7913's is 10^31 erg/s, and the unknown star's is 10^29 erg/s. T-Cha's and RXJ's higher luminosities could be due to flares which are common in young stars. To determine this, Rudy extracted the light curves of the stars. It seems as though T Cha and RXJ are showing some flaring, but it is not totally clear. The unknown star's light curve is pretty flat. He is going to try to extract a more clear light curve. I would post a pic of the light curves on here but it is a pdf and I'm not really sure how . . .you will have to wait until my presentation!

Friday, August 12, 2011

Day 28

Today was the last day for research undergrad students, and they all had to give presentations about what they've done over the summer. In the morning, Evelyn and I went to a few presentations. I took notes about things I liked/disliked about the presentations so that I can apply them to my own! For lunch we got to have free Chinese food which was awesome. I even ate with chopsticks! Afterwards, a few of us interns went to another presentation about using PTM images to diagnose medical problems. Then, we decided to explore the roof and helped out with a remote sensing experiment that was going on up there. It was a very fun day!

Day 27

Today we went on a field trip to CVI Melles Griot. It was this really small lens-making company and the tour was shorter than we expected. The lunch afterwards was really good though, we went to a sub shop. Afterwards I finished the excel sheet of the observations of MP Mus and T Cha. Then I spent the rest of the afternoon reading a paper about color-color diagrams and their correlation with a star's circumstellar disk. The infrared color-color diagrams that I will be working with are J-K vs. H-K. Using this graph I believe we can find out if any of the T-Cha or MP Mus candidates are brown dwarfs or not. 

Thursday, August 11, 2011

Day 26

Today I finished comparing the 2mass magnitudes and colors of the regions in T-Cha and MP Mus to the brown dwarf TWA 28. We plotted a graph of J-K vs. H-K to try and see if any of the regions could be brown dwarfs but apparently this method won't work unless I am sure that the stars are young stars. So instead, I started to record fluxes found at different microns for the coordinates of the regions, using HEASARC. I searched for observations made of these coordinates in the Rosat, Akari, Iras, Galex, Usno B1, and 2mass missions. Then I recorded the fluxes for the results that had an offset of  >1 arcmin from one of the coordinates. In addition, I also recorded the observation #, offset, count rate, and count rate error of observations that were returned without any recorded fluxes. In the end, the hope is to make a spectra graph that will show where the regions in MP Mus and T Cha peak. This will tell us more about what kind of star it is and what its temperature is. Also Rudy gave me an 11 page paper to read! Better get started on that . . .

Tuesday, August 9, 2011

Day 25

In the morning I worked a little bit more on my powerpoint. It was pouring when we went to coffee time but thankfully Matt let me use his make-shift frisbee (aka paper plate) as an umbrella. I couldn't resist a strawberry-mango smoothie today . . .they are so good!

In the afternoon I worked on trying to find the bolometric luminosities of T-Cha and it's two possible companions that are bright in X-rays. However, one of the stars we could not find in SIMBAD or in other published papers, which means that it hasn't been observed before. I'm not sure if this poses a problem though, I think that we can find out the bolometric luminosity from it's extracted spectrum. Anyways, I ended up finding two useful scientific papers and made a table of information for each. In one paper, I discovered pictures of extracted spectra for some stars and Rudy started to explain to me a little bit about how they name each spectra. I think I might spend some time tomorrow learning more in depth about this, it sounds interesting.

Today I also compared the 2mass mags (J, H, and K mag) and colors (J-K mag) of the regions in T-Cha and MP Mus (that aren't emitting x-rays) with the brown dwarf TWA 28 (companion to TW Hya). If any of the possible companion stars to T-Cha or MP Mus have similar characteristics to TWA 28, this could mean that they are not emitting x-rays because they are in fact a brown dwarf, and not because they are too old to be a companion star. Although none of the regions have exactly the same 2mass mags or color of TWA 28, some come close, but I will have to talk to Rudy or Joel to see how close they have to be.

Day 24

Today I went back into Topcat and re-downloaded the 2mass, UCAC3 and PPMXL tables for V4046 sgr. Then I located the GSC0739 and made sure its coordinates (273.59196  -32.76948) showed up in my final result. I ended up having to increase the pmDE (proper motion declination) by a few mas/year. Then I typed in each region's coordinates into ds9 that I found for the UCAC3 and PPMXL lists. It was tedious work, but they are much better results.

Today Rudy came back and he is going to extract the spectra of the bright, red, low-mass stars that I've found so that we can get more information about them. He said tomorrow he will explain to me what we can tell from the spectrum of a star. Afterwards, I continued working on my powerpoint presentation, and I realized I forgot to save all of the regions that I had previously typed into ds9 in the morning! I had simply saved an image of v4046 sgr with the regions without saving. So then I went back through and typed them in again, making sure I saved them this time!

Monday, August 8, 2011

Day 23

Today we went on a field trip to Xerox. It was really interesting to hear some of the new technology that they are working on. They are making a special camera that will be able to tell when people are smoking at gas stations, and another camera that can track a person's breathing. We also got a tour of the building where they manufacture the iGen4 digital press. Afterwards, Joel sent me an email that said that I should have a region around a certain X-ray source close to V4046 sgr, but for some reason it did not come up in my results from Topcat. Apparently it is a companion star to V4046 sgr that they call GSC0739 or V4046 Sgr C[D]. Unfortunately, I didn't have enough time to investigate this because I had to leave work a little early to babysit. However, it is on the top of my list of things to do on Monday.

Friday, August 5, 2011

Day 22

Today I spent most of the day working on my presentation. Until I finish my actual project though, I can't get too far on the presentation. Also, Rudy sent me and Joel (who is on vacation) images for each binary star that merge all three of the images from each instrument (Mos1, Mos2, Pn). I'm pretty sure I've finished what Joel instructed me to do before he left, but I won't be sure until he emails me back . . .hopefully soon. Also I'm not really sure what to do with the images Rudy sent us but I loaded the regions I made yesterday onto them and I think they look pretty good! Luckily, Rudy comes back tomorrow (I think?) but I won't be here for most of the day . . . we are going on a field trip to Xerox!

During coffee time, Matt persuaded me to play the trivia game even though I am horrible at it. This time the question was something about bobsledding, and while I had no idea what the answer was, Matt got the right answer for me! Since we wont be here for lunch tomorrow, we had our cookout today. It was super fun! Can't wait for Friday :)

Wednesday, August 3, 2011

Day 21

Today I worked on finding out if the stars I found last week are emitting x-rays. First I open (into ds9) the x-ray images of the binary star with each of the three instruments (MOS1, MOS2, pn) that has the longest exposure time. Then, I make regions with radius's of about 20 arcsec using the coordinates of the possible companion stars, or co-moving stars, I obtained last week. It's pretty exciting too see which ones are emitting x-rays, and how bright they are. I've discovered that while all of the binary stars are emitting x-rays, only some of the possible companion stars are, and they are much fainter than the binary star. I didn't find any x-ray emitting, co-moving stars to MP Mus.  . . .and while TW Hya (binary) is bright in x-rays, TWA 28 (its definite companion star) does not seem to be emitting any. I'm not exactly sure what these x-ray observations tell us about whether or not these stars I found could be companion stars to the binary, and unfortunately Joel is not here to tell me. I will have to wait for him to email me back.

For lunch I watched a movie about the Dyson guy and how he designed all of his awesome vacuums and other household appliances. I kinda want to get a Dyson vacuum cleaner now. Afterwards, I went to hang out at Prati and Liz's lab for a little while. They had to use a dongle for something . ..but we all couldn't stop laughing about the name of it the whole time. Afterwards I continued working on the x-ray observations!

Day 20

Today I researched X-ray observations that have been made of the possible companion stars I found last week. I used HEASARC (High Energy Astrophysics Science Archive Research Center) to find lists of X-ray observations from Chandra, Suzaku, Rosat, and XMM-Newton missions. Then, I used the observation numbers found in the "XMM-Newton Master Log & Public Archive" to get X-ray images of them. For each set of possible companion stars, I got images from the MOS1, MOS2 and pn instruments, and saved them as FITS files. The next step is to open the images in ds9, and make regions of the individual stars to see if there are any x-rays coming from them.

Monday, August 1, 2011

Day 19

Today, I spent the morning finishing reading the paper from Friday, and researching concepts mentioned in it that I didn't understand. In the afternoon, Joel was not here so I worked more on my final presentation. I started by sketching out what I wanted my slides to look like on paper (tip from presentation Zen movie I watched during lunch last Wednesday), and noting what information I needed to say/explain during the slide. Then I started actually composing the slides on PowerPoint and experimenting with different looks and transitions.