Carina Nebula

Astronomy 61: Current Problems in Astronomy and Astrophysics

Prof. David Cohen

Spring 2015
Friday 11:30 to 12:20
SC 113 (seminar room)


Townsley image windtabs transmission windtabs fit HD93129





posted 4/26

This is the last scheduled week of classes, and we'll meet on Friday at 11:30 as usual. But also, I'd like to meet the following Friday, May 8, from 11:30 to 12:20, as our final meeting to wrap things up.

Archive of old announcements.



posted 4/28

Please post your two-temperature and three-temperature fit results to the Google spreadsheet. I've completed those fits for my star, source 1, and posted my results. Have a look and note my conclusions (no strong evidence for significant wind absorption).

posted 4/26

I have put the spreadsheet with our program stars into a Google doc (actually a Google Sheet) and have sent you an email with a link to it. I've entered information about your initial fits to your sources, from last week. Please look it over and make sure the information I entered was correct. If the number of bins in your grouped spectrum is blank, please enter that information, too.

The next thing for you to do is to fit a two-temperature model to your spectrum (just the tbabs and windtabs with tbabs cases are required, no need to do a no-absorption model). Once you've done those two fits, send me the corresponding two plots, the fit parameters, and enter your chi-square values in the Google spreadsheet.

The next step will be to fit a three-temperature model, but with the temperatures frozen at kT = 0.4, 0.8, and 1.6 keV (again, two cases, tbabs only and tbabs with windtabs). And send me these two plots and enter the corresponding chi-square values in the Google spreadsheet.

Please complete the above two pairs of fits and send me your results by Tuesday.

After we compare the results of these different fits, we'll take the favored ones and explore the effects of changing the tbabs column density.

Archive of old assignments.



Class information

Class Moodle page

class information (posted before the semester)


Useful resources

Local computing information

ADS: for papers
astro-ph: for more papers
SIMBAD: for objects
Astronomical Catalogs: for catalogs

New: David's plots and fit results, posted

X-ray astronomy

Chandra X-ray Center
XSPEC manual: spectral fitting
ATOMDB webguide (line list)

General astro research information

Astrobetter – lots of useful information about the nitty-gritty of astronomical research and many aspects of being an astronomy student and astronomer

Astrobites – very short summaries of interesting research papers, written for undergraduates by graduate students.




This page is maintained by David Cohen
cohen -at-

Last modified: April 28, 2015