This project is a collaborative effort between researchers at the University of Wisconsin and Goddard Space Fight Center. This page presents my work on this project to date, which centers on reduction of Fabry-Perot images of Hale-Bopp in [OI]. Chris Anderson has a very nice set of pages detailing the MOS observations of Hale-Bopp.
Download a PostScript file containing the poster on the [OI] data reduction project that is being presented at the October 1999 meeting of the American Astronomical Society Division for Planetary Sciences. This poster concentrates on the water production rate of Hale-Bopp as determined by [OI] measurements.
A previous poster covered the remarkable asymetry in the [OI] emission. This poster was presented at the May 1999 meeting of the American Astronomical Society.
Here are some plots that are in the DPS poster:
Click on image to download a postscript file.
Click on image to download a postscript file.
Click on image to download a postscript file.
This recalibration results in the following [OI] images of the comet in the 6300 A [OI] transition taken by the WHAM Fabry-Perot spectrometer:
Click on image to download a postscript file. Click here to download a FITS file of the WHAM [OI] image. Click here to download a FITS file of the WHAM continuum image.
Click on image to download a postscript file. Click here to download a FITS file of the WHAM [OI] image. Click here to download a FITS file of the WHAM continuum image.
Click on image to download a postscript file. Click here to download a FITS file of the WHAM [OI] image. Click here to download a FITS file of the WHAM continuum image.
The [OI] emission is shown in color and the continuum (dust) emission overplotted in contours.
The surprising thing about the last two images is the marked asymmetry in the anti-sun direction. Past comets have exhibited symmetric distributions. The first image doesn't have the necessary signal to noise to detect the effect. Chris Anderson's Hydra MOS observations of Hale-Bopp in [OI] show a similar asymmetry. In the figure below, I compare the MOS data (lower three plots) with the WHAM data (upper three plots). The X-axis of the plots are angle, the Y-axis, surface brightness in Rayleighs. The different colors correspond to the different rings in the hydra MOS pattern . I have sampled the WHAM [OI] images in annular rings corresponding (in angle) to the annular rings in the hydra pattern. Asterisks indicate the continuum (dust) surface brightness in a pass-band equivalent to the width of the [OI] line and triangles indicate the surface brightness of the [OI] line.
Click on image to download a postscript file.
Below is a plot of the radial profile of all of the [OI] data we have reduced so far (including the recalibration of the February WHAM data). This plot replaces Figure 4 in the poster.
Click on image to download a postscript file.
Here I demonstrate that it is unlikely the [OI] asymmetry is caused by instrumental effects in the WHAM instrument.