From jhkpci@rit.edu Wed Jan 31 10:40:16 2007 Date: Mon, 22 Jan 2007 15:01:44 -0500 From: Joel Kastner To: "cpg3287@rit.edu" , "krg0775@rit.edu" , "acl7695@rit.edu" , "rmp7773@rit.edu" , "cxw8453@rit.edu" Subject: [UTF-8] assignment 5 [ The following text is in the "UTF-8" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] Hi, I've posted a link to the directory with the 100 ks XMM image of the V1647 Ori field on the class website. On Weds we can go into more detail on the specifics, if you like, but the gist of assignment 5 is: 1) Using a bright point source on each image, compare the PSFs of the Chandra and XMM images with each other and with the theoretical "best PSF" limit lambda/D, where lambda is ~1 nm. You can find the approximate D's by looking at the Chandra and XMM web pages (chandra.harvard.edu and http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31250). (I was wrong, by the way, the Chandra and XMM telescope designs are Wolter Type I not Type II...!) 2) For all X-ray sources within about 5'x5' of V1647 Ori, find total counts on each image (using SIP). Tabulate the values and plot them against each other (probably best to use a log-log graph). 3) Using this plot (and/or any other way of plotting the results that might be helpful), see if you can identify: a) sources that appear relatively constant in X-ray count rate vs. sources that are clearly varying in X-ray count rate (i.e. sources that were clearlty much fainter/brighter in the Chandra image than in the XMM image) b) a typical relationship between Chandra source counts and XMM source counts for the "constant brightness" sources (if there are any!) Good luck! -Joel p.s. be sure to save all the tables you've been compiling along the way (i.e., JHK for 2MASS sources, 2MASS counterparts to X-ray sources, etc) as there's a nice final project taking shape here... ** This email was sent from 1051.217.01 - Fund Astronomical Imag ** From jhkpci@cis.rit.edu Wed Jan 31 10:40:42 2007 Date: Mon, 22 Jan 2007 15:08:54 -0500 (EST) From: Joel H. Kastner To: "cpg3287@rit.edu" , "krg0775@rit.edu" , "acl7695@rit.edu" , "rmp7773@rit.edu" , "cxw8453@rit.edu" Cc: Joel Kastner Subject: Re: [UTF-8] assignment 5 p.s. I should have been more careful, when I said to identify sources that were "much brighter/fainter in the Chandra image than in the XMM image". All sources will (I think) *appear* fainter in the Chandra image than in the XMM image, because XMM is more sensitive than Chandra. So it's necessary to account for this difference in sensitivity -- for example, by finding the average (mean) of source counts in each image and then plotting each source's counts divided by this average, when comparing the two images. We can discuss further on Weds... On Mon, 22 Jan 2007, Joel Kastner wrote: > Hi, > > I've posted a link to the directory with the 100 ks XMM image of the V1647 > Ori field on the class website. On Weds we can go into more detail on the > specifics, if you like, but the gist of assignment 5 is: > > 1) Using a bright point source on each image, compare the PSFs of the > Chandra and XMM images with each other and with the theoretical "best PSF" > limit lambda/D, where lambda is ~1 nm. You can find the approximate D's by > looking at the Chandra and XMM web pages (chandra.harvard.edu and > http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31250). (I was > wrong, by the way, the Chandra and XMM telescope designs are Wolter Type I > not Type II...!) > > 2) For all X-ray sources within about 5'x5' of V1647 Ori, find total counts > on each image (using SIP). Tabulate the values and plot them against each > other (probably best to use a log-log graph). > > 3) Using this plot (and/or any other way of plotting the results that might > be helpful), see if you can identify: > a) sources that appear relatively constant in X-ray count rate vs. sources > that are clearly varying in X-ray count rate (i.e. sources that were > clearlty much fainter/brighter in the Chandra image than in the XMM image) > b) a typical relationship between Chandra source counts and XMM source > counts for the "constant brightness" sources (if there are any!) > > Good luck! > -Joel > > p.s. be sure to save all the tables you've been compiling along the way > (i.e., JHK for 2MASS sources, 2MASS counterparts to X-ray sources, etc) as > there's a nice final project taking shape here... > > > ** This email was sent from 1051.217.01 - Fund Astronomical Imag ** > >