So now, what else can we do? Well we can actually create, almost a, contour map, like a topographic map on the Earth, to see which parts of our images, have equal intensity. And the way we do that, is contours. If we click on Contours, and Contour Parameters. You can see that what we have generated are regions, that have equal amounts of intensity. And this can be utilized in a number of ways to kind of outline what parts of the image we want to look at. The best thing to do here, to see this, is to imagine that we change our scale. Let's go to our square root scale. And, now you can see these particular contours, not particularly useful. But now, here are the levels that we have displayed. Those represent the regions that have particular intensities. And notice this is a linear scale. We've just gone to our square root scale. And now we can generate an entirely different set of levels. First of all, we only have four, other than zero, here. Let's change the number of levels to, oh, about ten, I guess. Nine. We'll leave, we'll talk about the smoothness in just a little bit. But now since we have a different scale. Let's generate those. If we generate those, you can see that now we have a whole new set of values. And we can apply that. And now you see an entirely different set of topographical positions where intensities are the same. Let's now go though to instead of a linear scale, a square root scale. Let's generate those, and apply them. And now you see a set of different intensity levels. And as we have considered before, we have generated more faint levels out here. Now in order to see that a little more clearly, let's average this so that we don't get quite the same amount of detail. But we kind of like add up a bunch of pixels, take their average so we can smooth it out. So let's change our smoothness. And do an Apply. And now you can see different levels of intensity, as a function of position. In order to see that more clearly, let's go back to our linear scale. And now you can see that we have a set of levels that shows Cas A to be very, very bumpy with all sorts of little things sticking out. And in particular, now I'm going to right-click here, and do our handy-dandy contrast and bias thing here. Okay, now you can see that there's this region out here, which is like a blow out region, where it looks like a balloon has almost popped. And we'll be talking more about this when we actually talk about Cas A in detail. And now let me show you a little bit about what happens with these two windows. Okay this window is actually a panning window. What you can do is click within this blue box And you can move your region of display around. So if you want to consider a different part of the image, you can move that box. And now you see the image has jumped. So you can reposition things. Just the way you want to. You may want to center it, you may want to just look in at a particular part of it. We can do that by zooming in. Go to Zoom + Plus, and look at the blue box here. Get smaller and smaller because that's what we're looking at. And now you can start seeing the individual pixels of the Cas A observation, and you can see the digital aspect of things. Okay, let's go to zoom again, and go back out. And here we are back to more or less normal. Now each individual pixel in the Chandra instrument section, represents 1/2 of an arc second on the sky. The smaller that number is, the more resolution you have in any observation. In the case of Chandra, we have a 1/2 an arc second for each of these individual pixels that you see going from here to here. Well now we have just kind of looked at these images. We haven't really done anything with them. And what we're going to do now, is actually look at the data behind this particular observation. And in order to do that, we are going to click anywhere in the observational field. And when we click at that point, we are going to lay down a region. We click, and there is that little green circle. That represents that part. And we'll select out that part of the image for further analysis. Laying down the region is a single click. If you click once again, click from within it. You see that you get four little squares in the corners. These are handles that you can grab, by clicking and dragging. And making your region as large or as small as you want. Now, if you accidentally lay down a region, you accidently go click, which is going to happen to you all the time, okay? What you do to get rid of that region is first select it, one more click, and then just hit your delete key. Boom, region gone. And in fact if you look at the region menu here, there is a delete button that allows you to delete any region that you want to. We're going to look at the energy spectrum that is present. Or the range of energies that are present, in each of the photons or all of the photons, in this particular observation. So what we're going to do is we're going to select this region. We're going to drag this out, so that the region encompasses more or less the whole observation. And now we're going to go to the Chandra-ed analysis tools. And look at the Quick Energy Spectrum Plot. We click on that. And what happens is, is the analysis server looks at every single photon In that region. And gives us the number of those photons detected as a function of energy. Now in X- rays we usually refer to energy in keV, or eV. So this particular number of 2,000 says that photons, all the photons in a small band centered on 2000 electron volts lay here. You can see all of these bumps here. What are these bumps? Well, we're going to find out later, that this a fingerprint signature of the elements that are present in this particular object in the sky. And we're going to be utilizing energy spectra many, many times over the next couple of weeks. Now I'm going to go to particular parts of the super nova remnant. And in particular, I want to go to x at about 40, 50. Well that's pretty good. And y of about 40, 100. That's pretty good. I'm going to lay down that region. Okay? Now I'm going to do a quick energy spectrum for that particular segment of the observation. And that's what it looks like. Lets bring that over here. Now, I'm going to choose a different region. I'm going to choose a region that is at 45, 50 or 45, 30 about. See, what I did here is I cruised around. Obviously a number of years ago, looking for particular Interesting possibilities of exploration, and came upon this particular spot. So I know that this spot is there, and you can do that with lots of these observations on your own. Cruise around, see what's interesting. Okay. So I'm looking for 45, 30 and 41, 76. Oh, about there. Okay. Here is the region that I want to look at. Oh, by the way, if you want to move it around. You can kind of, click and drag it, once it's selected. So you can put it more or less where you want it. So there's our region selected. Now lets do once again, a quick energy spectrum. Look at the difference between these two particular regions of the observation. In one case, we have this enormous spike right over here. Just over 1 keV. In this case, that spike is much lower, but the 2 keV spike has now reared its head. And this shows us that the evolution of the supernova remnant is not something that just is like an expanding balloon or sphere, that's spherically symmetric. Things are happening in very small regions of the supernova remnant, that demand attention. And this is an active field of investigation today, in the X-ray astronomy community. What I want to do now is load a different object, the Coma cluster of galaxies. We're going to go back, and we're going to look at another observation. And in this particular observation, we're going to load the image of the Coma cluster. Here it is. This is a cluster of galaxies, hundreds and hundreds of galaxies That is faintly glowing, or actually quite remarkably strongly glowing in the X-ray region. Just everywhere within the cluster of galaxies. A very, very big surprise When we actually discovered this, in the Uhuru satellite many, many decades ago. Well not that many decades ago, but a number of decades ago, in the 1970s. Okay so now we've loaded Coma. What I want to do is select color b. I want to look at a scale that is the square root. Now you can see in fairly bold relief what is happening in Coma. Notice these crosses here. Those are just artifacts from the satellite itself. And represent the different parts of the detector that exist on the Chandra satellite. So this is an observation that actually spans several of the chips that are present. In the satellite. So now, in order to proceed further, what I want to do is go to Frame. And now we're going to select another frame to load another image. The first thing we do, is when we look at frame, we go to Tile Frames. And that will now allow us to put another frame right next to this particular observation. What we do is, to go further, we go to our Image Server, here under Analysis. Right, here's our Analysis menu. And we're going to look at SAODSS. This is the digital sky survey of a particular part of the sky, that corresponds to the region of the Coma cluster. And so we're going to ask they sky survey to retrieve that part of the sky, that corresponds to the Coma cluster. This is going to take a little bit of time, because it's looking at a fairly large region of the sky. But pretty soon, you will now see displayed the image in optical light of the Coma cluster. Now, what we want to do is align these two frames, so they display exactly the same parts of the sky equally. Notice, okay, and this is something that is a little bit tricky. There's a very, very faint green blue line around this frame. That means that, that frame is selected. What I want to do is go back to the X-ray frame, and select that. So I'm going to click on it. Now the blue fla, frame line appears very, very faintly. Hard to see around this observation, and doesn't appear over here. Now what we're going to do, is go to Frame. And now we're going to match the frames. We're going to say match the frames in the world coordinate system, which is essentially right ascension and declination. And that's going to rescale, look at what happened, it rescaled the right hand image, so that now it exactly corresponds to what's going on in the left. Now notice here, almost every single object in this field of view, is another galaxy, with billions of stars in it. It's truly a large conglomeration of galaxies that is gravitationally held together. And we see it in the sky as the Coma cluster. Now, what can we do? Well now we're going to go to the Edit part of our Menu bar. And, instead of having a pointer, we're going to click on Crosshair. Now, looks what's happened. Our, our arrow has turned into a crosshair. And now if we go back to frame, we can lock the crosshairs. Now we can drag any one of those crosshairs, and look at what happens to the other. You just click on one, and now you can cruise around, and see. Let's suppose you want to see how much X- rays are coming from here. This part here, and look at this object here. Very, very bright both in the X-ray position, and in the optical position. Here we have another object. Very, very bright galaxy in both X-rays and in optical. However, look at this guy. This guy is just an ordinary star. We see it in the optical, but in the X-ray there's almost nothing. So now we can do all sorts of different types of analysis, using more than one image. And we will be utilizing this feature as well, in the coming weeks. Okay. So now, I want to do one last thing. And this is just going to look at the energy spectrum of the Coma cluster, just like we did for Cas A. Now we have our X-ray image of Coma back. And, do something a little bit different. I'm going to make the region shape instead of a circle, I'm going to make it an ellipse. Because this is an elliptically shaped object apparently. Okay I'm going to lay down that elliptical region. Select it, and now I'm going to kind of drag it around here. Well this is not too bad. So now I have selected that region, let's do another energy spectrum. Here's our Chandra-ed analysis tools. Do a quick energy spectrum plot on the Coma cluster of galaxies, and look at that. Here is an energy spectrum that is very, very different from the energy spectrum that we generated for Cas A. And these are some of the interesting types of differences and similarities, that we will see among X-ray sources in the future. We will be looking at many, many different facets of X-ray sources. And utilizing ds9, but by now, you should have. Some feel for how you can manipulate the images, within the confines of ds9. And there's a manual online, you can look at this in as much detail as you want. I hope you have enjoyed your ds9 smorgasbord. I encourage you to go out into the Chandra-ed archive. Download as many sources as you can. Look at them and play around with the data, and see what you can come up with. [BLANK_AUDIO]
