From jhkpci@rit.edu Tue Jan 16 16:53:11 2007 Date: Fri, 12 Jan 2007 15:05:59 -0500 From: Joel Kastner To: "rmp7773@rit.edu" , "cpg3287@rit.edu" , "krg0775@rit.edu" , "acl7695@rit.edu" , "cxw8453@rit.edu" Subject: [UTF-8] Next assignment (#4) [ 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. ] Here's the general idea for assignment #4. Hopefully you now know how to do all of these steps. We can review on Monday, as necessary. The assignment is due Friday 1/19/07. -Joel *** 1) Download the Chandra X-ray Observatory image from the class website, and read into ds9. Examine the image, noting key differences between this X-ray image and the IR images you've been working with so far. Is V1647 Ori an X-ray source? 2) Create a ds9 regions file with circles at the positions of all obvious X-ray sources within about 4 arcmin of V1647 Ori. I estimate there are about 20 sources in this region. Use this file and the 2MASS source list you previously created to identify the 2MASS "counterparts" to the Chandra X-ray sources that lie near V1647 Ori (that is, which X-ray positions correspond closely to the positions of 2MASS IR sources?). Check your work by loading the X-ray regions file onto the 2MASS images. 3) For the above sources, make a table (in Excel or whatever) listing * X-ray source number (just a sequential list, from lowest to highest RA) * X-ray source position * 2MASS counterpart name * 2MASS J,H,K magnitudes * net X-ray source counts * net J, H, K (2MASS) source counts For the "net counts" measurements, use the SIP tool (see class website). 4) Plot a few quantities to see if you can discern any trends, such as: * do X-ray source counts scale with IR source counts? (I.e. are X-ray and IR source intensities correlated?) * does X-ray source intensity depend on IR color? * does the ratio of X-ray/IR counts depend on IR color? (log-log plots are probably a good idea, for each of these tests...) ** This email was sent from 1051.217.01 - Fund Astronomical Imag **