[BLANK_AUDIO] The first thing we want to do is generate an energy spectrum of the entire remnant. We have seen this before. We open DS9, go to Analysis, go to Virtual Observatory, Connect to the Records Primary Mook. Select asis observation of casa obsid114. And there it is. For clarity, so we can see things a little better, let's just change the scale to a logarithm. And now, we'll click on the central object. When we click on the central object, we create a region. We can click again to select the region, and now we're going to drag it out so that it encompasses approximately the entire remnant. Now, we can go to analysis, let's cut off our analysis program here and then cut off our [INAUDIBLE] head analysis tools and we are going to look at the quick energy spectrum. And here we have a plot of what the energy output of Cas A is like. Each one of these peaks represents the presence of a different chemical element. Now if you do this observation carefully, and this analysis carefully, we can look at this particular result... Which represents the same thing as we looked at just now except kind of color codes all of the photons in an interesting fashion. Notice that everything red here Is up to about 1 and a half KEV. Then we get a green region here, color coded green, which goes up to a little over 2 KEV and includes the lines of silicon that we see here. And then a blue higher energy region that includes Sulfur, Argon, Calcium and Iron. So we can do something now very exciting. Lets actually create our own three color, Image based on the energies that we see here. We're going to look at the photons less than 1.5 KEV in red, 1.5 up to 2.2 in green, And 2.2 to 10 KEV in blue. This will allow us to isolate the various emissions from neon, magnesium, silicon, sulfur, calcium, etc, etc. So we can return to DS9 and do the following. First I'm going to ask you only if you have a Windows machine. This is above the Windows I've presented us with that we've solved in the following fashion. What I'm going to ask you is make one small change to your preferences and if you are doing it from that you don't have to worry about anything. Go to edit, preferences. And when you see general, right down here in dialog box. Just make sure that the windows radio button is checked. This will allow you to be able to save your files in the proper fashion. Ok, so now the first thing we're going to do is go to our analysis changer edit tools, and we're going to create an energy filter, we click on energy filter. And you see that we can enter the values for the two lower and upper energies that, you would like to look at the photons for. So, here we have .1 KEV. And over here we're going to go up to 1.5. We click okay. And now, you see, next to our original frame, we now have selected out, although you really can't tell, that these are photons from 0.1 to 1.5. Okay, z's actually r, and it'll be interesting. I'll show you in just a second an interesting way to show that in fact that's all that there is here. Well first thing we're going to do, notice that this frame is selected with this little blue line surrounding it. We're going to save this. We want to save this file. And, we're going to save it as a fix file. And, we're going to put it on our desktop. And, we're going to call it red.fix because that's going to be our red color. So we save it. Okay, and now, after we do that, we click back to our original. Okay, here we now clicked on our original frame, and now the blue line is surrounding the original frame, and now we're going to do another energy filter. And in this particular case, we're now going to use as our low energy 1.5KEV, and our high value is going to be 2.2. We click OK. And bada boom, now we've got our green filter. Energy from 1.5 to 2.2. We're going to save that. And we're going to save it this time, instead of "red" we're going to call it "green". Whoops! green.fix. We're going to put it on the desktop, and we're going to do a save. Yes, we'll do that. Okay now I'm going to ask you an interesting question now. What would happen if you didn't click back to the original frame? OK and you did another energy cut. Why would that happen? Why don't you try it? In other words here's our point 1 to 1.5 frame. What would you get if you did an energy filter on this frame from say 1.5 to 2.2. You'll get an interesting thing. And you'll learn a lot about what we're up to, in this particular situation. Anyway, we're going to now click back to our original. Okay and we're going to do our last energy filter and that energy filter is now going to be 2.2 KEV. Up to 10 KEV, we're going to click on that, here it is, we're going to save it, and this one we're going to call, guess what? Blue.fix. We save it. And, now watch. We're going to combine them all. What I want you to do now, or what we're going to do, is just for clarity, you can see that as we increase the number of frames displayed here, it kind of looks a little grotty. So let's delete all of these frames and we'll start from scratch. We go to Frame, we go to delete, delete, delete, delete. Oh, all gone. Now, we're going to do something really cool. We're going to go to frame and we're going to click on new RGB. That's for red, green, blue. So, when you do that, up comes this little teeny box. And this is telling us that we're currently working with the red part of our frame. We go to file, we're going to open and guess what we're going to open folks? We're going to open the red.fix file. And there it is, in red. Okay. Now let's go. What happened to our little? There it is. Okay. Now let's click on green. We go to file. We open. Guess what? Green dot fits. And that's superimposing the green. Photons, over, they're really not green photons right? They're 1.5 to 2.2 KEV x rays, very, very high energy. And we do it one more time, with blue. So we do blue, and we go to File > Open And now we look at our blue dot fix file. Superimpose and now [LAUGH] there it is. Look at this.This is really, really cool. But now we can do more. We can select each of these colors and adjust our color map parameters.This is really, really neat. Okay let's go to color and let's just kind of extract out the color map parameters here, and we'll place them over here. And now we can manipulate the contrast and bias in each one of these channels until we get something that we like. So what I'm going to do in this particular situation, is first select our red channel, and I'm going to go to scale and okay it's kind of it's, it's in log arithmic form anyway, I'm not quite sure What min max is doing checked here. But, we've got logarithm here. And let's just kind of adjust this a little bit so, I'm just going to, oh, you know, this is cool to look at. Let's pull this out of our way here, so you can see what happens to the color map parameters. Remember, you can utilize the mouse. Right click and you can go left and right and adjust the bias. Up and down and adjust the contrast. So we can get something like, oh, let's try, somewhere in here. I'm not sure which ones I'm going to like the best. This is not too bad. Okay. Now let's go to green. We can do the same thing with the green channel. Whoops. [BLANK_AUDIO] That's kind of interesting. Now lets go to the blue channel. Let's kind of adjust up and down here. And now you have generated an energy plot. Instead of just a function of intensity we're now looking at specific energies associated with this supernova. And looking at the lowest energy ones in the red regime The middle energies has a green component and the higher energies has blue. And you can have a lot of fun with this stuff just generating these kinds of images and seeing what you can come up with. The best one that I came up with, I'm actually enter into the parameters here. So you see what this one looks like. I'm going to go to red and I'm going to change the red to 3.6, oh, it was pretty close, at 3.6. 3.6 and the bias I wrote down is about .715. That's pretty good. And then for green, I seem to like contrast of point Nine, eight, seven, that's pretty close. And bias of 0.51, that's pretty good. And then for blue, I seem to like Contrast of 4.95, 4.9, well that's close enough. And 0.6, and there you see it. Okay. Not sure why I like the green like this, but I could just kind of adjust that if I wanted to a little bit. kind of deemphasize green a little bit, there we go. That looks pretty neat. Okay, I almost forgot the most important thing. And that is when you are satisfied with your image that you have created, you can go to File click on Export and choose one of these photographic media formats I usually like PNG because it's lost less. You click on that, and save as whatever name you want to give it. Let's call this Cas-A five Click on save, and now you will have it on your desk top, or whatever file folder you chose to put it in. And it'll be a convenient way for you to be able to display this image, and any others that you might create. So let's go back to the black board and see what we can learn from this in exploring our results that we just generated here further. Here are three representations of what we just did. With various scales and color map perameters selected. What we see immediately, is that all of these represntations are asymmetric. Whatever is happening here it is not happening everywhere at once, and in the same way. You will be exploring this further in your homework this week. Indeed, this area is also a subject of intense research in the astronomical community. We really do not fully understand the fundamental nature of supernova explosions. How are they triggered? How do they evolve through the interstellar medium? We have certainly made progress in answering these questions but exciting work remains to be done. The progenitor that led to the development of CAS-A Is an example of a so-called type two explosion, a core-collapsed supernova. A massive star, greater than about eight solar masses, suffers a spectacular implosion, because at the end of its life, it can no longer generate enough energy to support itself against the ever-vigilant force of gravity. The collapse stops abruptly when neutron degeneracy sets in, and the material then experiences an incredible bounce, literally like running into a brick wall, thereby sending a shock wave back outward through the star. Which starts the process of forming the remnant that is still evolving today. Next week, we will meet another form of supernova, the so called, type 1As. Which occur in binary star systems and involve white dwarf stars. The observation of these objects led to a remarkable discovery about 15 years ago. Namely that the universe was accelerating despite the pull of gravity between its constituents due to some mysterious form of dark energy. The universe is indeed filed with surprises. So we have come full circle, the ancient start that once shone on the night sky billions of years ago has exploded and sent out the material for the birth of future stars into space. Where some day, possibly billions of years from now, the calcium we see in the spectrum may ultimately form into bones, and the oxygen may form part of a planetary atmosphere where life may flourish. So things are not so bleak after all. Even though our sun may die the seeds for its rebirth are contained within itself to be recycled, possibly endlessly, through the vastness of space and time.
