1. 1 De-Fringing Michelle Spectra Through Fourier Filtering GEMINI NORTH TELESCOPE HILO, HAWAII INTERN: MEGAN ANSDELL ADVISOR: SCOTT FISHER

2. 2 MICHELLE Facility imager and high-resolution spectrometer Mid-Infrared (7-26 microns) Dust, comets, planet forming disks, black holes Cold Objects (300-500K) IR spectrum used to study mineralogy and composition

3. 3 INTERFERENCE WITHIN DETECTOR BACKGROUND FRINGES ON SPECTRA FOURIER FILTERING

4. 4 DOESN’T DISTORT SIGNAL MATHEMATICAL PROCESS THAT REMOVES FRINGES FREQUENCY DOMAIN

5. 5 SPATIAL DOMAIN SHORT λ LONG λ } SIZE OF OBJECT A RAW SPECTRUM FROM MICHELLE (what we see at the telescope) OBJECT SIZE.

6. 6 FREQUENCY DOMAIN POWER SPECTRUM (same data, Fourier transformed) Scott Fisher, Spatial Domain Scott Fisher, Frequency Domain

7. 7 FOURIER TRANSFORM MICHELLE SPECTRUM (Spatial Domain) POWER SPECTRUM (Frequency Domain)

8. 8 CREATING THE MASK POWER SPECTRUM (frequency domain) THE MASK (symmetrical)

9. 9 REVERSE-FOURIER TRANSFORM MASKED POWER SPECTRUM DE-FRINGED SPECTRUM (Spatial Domain)

10. 10 SEEING THE DIFFERENCE BEFORE AFTER

11. 11 THE PROJECT Available on Gemini North website Make Fourier Filtering of high-resolution MICHELLE spectra as easy as the click of a few buttons Use IDL (Interactive Data Language) to write program and GUI (Graphical User Interface) Distribute to researchers who acquire MICHELLE spectra

12. 12 Interactive Data Language

13. 13 EXPERIMENTAL PROGRAM

14. 14 FINAL PROGRAM

15. 15 Distributed to anyone who acquires MICHELLE spectra from Gemini Available to download from Gemini North website Can be modified for use on any spectral data THE FUTURE

16. 16 ACKNOWLEDGEMENTS I would like to recognize Scott Fisher at Gemini North Observatory in Hilo for donating his time and expertise to guide me through this project. Thanks to Sarah Anderson, Malika Bell and everyone at CfAO in Santa Cruz for making this internship possible. This work has been funded in part by the National Science Foundation.