Downloading Chandra catalogs and Crossmatching to SDSS objects

Step One: use the ChandraCrossmatch.ipynb notebook to download and crossmatch the Chandra data with the SDSS data for Abell 2065. After doing the download/crossmatch, make the following plots:

Do these plots make sense?

Step Two:  Plot X-ray hardness vs X-ray S/N. Which objects are most likely to be AGN? Objects with X-ray hardness HRhs > -0.5 have a very hard spectrum (dominated by high-energy X-rays) and are likely AGN. Softer X-rays could still come from AGN, but are less likely. But pay attention also to S/N, and think about how well-measured the X-ray hardness might be.

Step Three: Plot r0 vs SDSS-Chandra crossmatch separation. Define a "well-matched" criterion to use when selecting sources.

Step Four:
Make a cluster color magnitude diagram (CMD), showing the following (each with a different marker style):

Which of the X-ray sources  are good candidates to be part of the cluster? Which ones probably aren't in the cluster?

Step Five:
Use show_in_notebook or show_in_browser to look at a table of your well-matched X-ray sources. Find the SDSS positions of the X-ray sources that are possible cluster members, and find them using SDSS Navigator. What do they look like, morphologically? Spectroscopically?

Note: The Chandra Crossmatch notebook uses an astropy affiliated package called astroquery that is not part of the normal astropy package, and needs to be installed on your computer. The installation commands are slightly different depending on how your python is installed (I think most of you use anaconda, but here are instructions for both anaconda and pip). In a system window (not in your jupyter notebook!) you want to type:

If you can't get astroquery installed, let me know and I'll make the Chandra data files available to you.