Ay 20 Lab Assignments

Instructor: Phinney

1. Observing Proposal (due 13 October 2008) Instructions.
2. Details of the accepted proposals.
3. Students working on the projects:
   • Tumbling asteroid: Landers, Maseda, Hensley
   • Star formation in interacting galaxies: Forbes (theory), Bilinski (theory/interpretation), Karkare (filters), Feldman and Silsbee (local and integrated Halpha fluxes),
   • ??: Taak
4. As of Nov 17 2008, the calibration star data and the off-band and on-band Halpha galaxy images are available for the two interacting galaxy pairs, Arp 140 and NGC 520, and for NGC2339 (the non-interacting `control' galaxy). The images of the latter are shown below [off-band (L) and on-band Halpha (R)]

   

5. As of Nov 17 2008, the full set of asteroid data is in hand. Drew's instructions on how to access and manipulate the data are here. See Drew for the username and password!
6. Some references that may be helpful in the tumbling asteroid project:
   • Short web introduction to asteroid spin evolution.
   • Model light curves of tumbling ellipsoids.
   • More of the same .
   • 2006 discussionof what can be learned from asteroid light curves.
   • Theoretical discussion of physical effects changing asteroid rotation.
   • 2007 Compilation of asteroid lightcurves.
7. Some references that may be helpful in the Halpha project:
   • Text on photoionized gas and Halpha emission or
   • (same earlier edition).
   • Early work on relation between star formation rate and Halpha emission.
   • More recent work .
   • Evidence that galaxy interactions enhance star formation.
   • Simulations of star formation in interacting galaxies.
   • Star formation triggered in close galaxy pairs.
   • Online code for making starburst models
   • Classic early paper explaining the appearence of colliding galaxies.
   • The `right' answer for Arp 140.
8. The list of P60 narrowband filters is here . Rest Halpha is at 6563 Angstrom (in sealevel air; it is 6565 in vacuum). The filter names are supposed to be the central wavelengths and widths e.g. 6564/21 should be the rest Halpha filter, 21 Angstroms width. So in principle they cover the redshift range up to (6640/6563 -1) i.e. z=0 to 0.012 or radial velocities up to 3,500km/s (galaxy distances to 50Mpc). HOWEVER All the transmission graphs are clearly wrong, and some of the names may be wrong too: e.g. 6564/100 looks nothing like 6563/100, and why would there be two filters 100 Angstroms wide with centers only 1 Angstrom different? Considering the 6564/21 filter the transmission graph peaks at 6576 Angstroms, not 6564, and it has a FWHM of about 30 Angstroms and a full width zero intensity of about 66 Angstroms. If the graph were correct, the equivalent width of the filter would be about 13 Angstroms. None of these reflect the /21 extension. All the other filter graphs have the same issue. Someone should remeasure these filters and make sure they are labelled properly!
9. Writeup: due in class Friday Dec 5. That class will be devoted to oral presentations of the results. Please prepare slides in Open Office/PowerPoint/Keynote or other similar format of your choice. Writeups should follow the format:
   1. Introduction -explaining why the project is interesting, scientific context. Motivating the project.
   2. Data Gathering -explain what data was gathered, when, with what instruments/filters/standards.
   3. Data Reduction -explain all the steps and software, equations, etc you used to convert the raw data into scientifically useful numbers for the next step:
   4. Analysis -explain the concepts and equations you used to get meaningful scientific conclusions from the data.
   5. Conclusion -summarize the results and put them in broader scientific context. What would you do differently next time?
   6. Acknowledgements.
   7. Bibliography of references used.