1. Extracting the Mystery from the Red Rectangle Meghan Canning, Zoran Ninkov, and Robert Slawson Chester Carlson Center for Imaging Science Rochester Institute of Technology

2. Overview Research Objectives Background Methodology Progress To Date Further Investigation Conclusions

3. Objectives Short Term –To Accurately Model and Remove Stellar Objects from Spectrophotometric Images of Emission Nebula by Way of Profile Fitting Long Term –To Characterize the Extended Emission Present in the “Red Rectangle”

4. Emission Nebula Red Rectangle –Star HD44179 –Biconical nebula –X-shaped pattern in red region of visible spectrum

5. Emission Nebula –Optical Spectroscopy

6. Methodology Acquire spectrophotometric images of Red Rectangle Fit a point spread function to nebula’s central star at reference wavelength (525 nm) Remove profile from images corresponding to spectral emission lines of interest

7. Image Acquisition UTSO 60 cm telescope Front-illuminated Kodak KAF-4200 CCD inside Photometrics CH-250 camera head

8. Image Acquisition Cambridge Research & Instrumentation, Inc. Varispec Tunable Liquid Crystal Filter –Fixed spectral bandwidth of 10 nm –Central wavelength tunable between 400 and 700 nm –31% transmittance at 700nm; 5% at 435nm

9. Spectral Characteristics Exposure time = 800 sec Image 1 - 525 nm Image 2 - 638 nm Exposure time = 400 sec

10. Methodology Find coordinates of peak intensity of like objects in Image 1 & Image 2 Calculate scaling with respect to intensity of Red Rectangle in Image 1 Fit appropriately scaled PSF Subtract profile from coordinates of peak intensity

11. Processing Image Reduction Analysis Facility –DAOPHOT package (NOAO/Tuscon) DAOFIND - locates coordinates of peak intensity PHOT- calculates photometry parameters PSF - Fits a point spread function ALLSTAR- Removes psf from stellar objects

12. Photometry Parameters Object Red Rectangle 525nm Faint Star 525nm Red Rectangle 638nm Peak Intensity PSF Scale Factor 6279.2261.0000 2602.091.2430 7837.1540.4144

13. Imaging Fit Gaussian Profile at 525 nm –FWHM = 10 pixels –PSF radius = 37 pixels Column (pixels) Pixel Value

14. Profile Testing Does the psf accurately model the central star at 525 nm? Can the psf be accurately scaled to fit other stellar objects: –within the 525 nm frame? –in frames recorded at 638 nm?

15. PSF Removal - Central Star =525 nm Column (pixels) Pixel Value

16. PSF Removal - Faint Star =525 nm Column (pixels) Pixel Value

17. PSF Removal - Red Rectangle Reconstructed Image of Nebulosity at = 638 nm

18. Red Rectangle - 638 nm Red Rectangle -Reconstructed Column (pixels) Pixel Value Column (pixels) Pixel Value

19. Analysis Virtually Faultless Removal of psf from central star in Image 1 –Only Poisson noise from fit remaining Removal of psf from faint stellar object in Image 1 results in a small peak intensity (~250) surrounded by a negative “dip”

20. Analysis PSF is not good enough –Fit is too small at the peak intensity; too bright in the wings May be some emission at 525 nm causing an inaccurate fit to the central star Consequently -extended emission at 638 nm is inadequately reconstructed

21. Further Investigation Fit psf to an average profile taken from several stars in Image 1 –Small FOV - OTF constant over frame Apply profile testing methods Verify registration/centering accuracy

22. Conclusions Many variables involved in psf fitting Encouraging Beginning –Further testing of psf accuracy and centering algorithms must be completed before success in generating a representation of the extended emission can be achieved