Long-slit spectra of the Red Rectangle at 3 $\mu$m

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Session 49 -- Interstellar Dust and Polarization
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[49.04] Long-slit spectra of the Red Rectangle at 3 $\mu$m

G.C. Sloan, Jesse Bregman (NASA Ames), C.E. Woodward (Wyoming)

We have observed the Red Rectangle with the Cryogenic Spectrometer (CRSP) at the 2.1 m telescope of Kitt Peak National Observatory. The Red Rectangle is a well-known source of the infrared emission features associated with polycyclic aromatic hydrocarbons (PAHs). Our long-slit spectra cover the 3.2-3.6 $\mu$m regime, which includes the strong PAH band at 3.29 $\mu$m, a weaker component at 3.40 $\mu$m, and an emission plateau which continues out to 3.6 $\mu$m. Emission in the PAH bands extends several arcseconds to the north and south of the central source (HD 44179). The seeing during our observations was approximately 1.5 arcseconds, but we have deconvolved the point spread function from our spectral images at each wavelength using maximum entropy reconstruction, allowing us to examine the relative behavior of these emission components at finer spatial scales. With the new 256$\times$256 array installed on CRSP, each pixel covers 0.6 arcseconds of sky. Our reconstructions reveal that the strength of the small 3.4 $\mu$m emission feature increases with respect to the 3.3 $\mu$m feature as the distance from the central source increases. In particular, there appears to be a region of enhanced 3.4 $\mu$m emission roughly 3'' to the north and south of the central source. We are analyzing our results in terms of the competing models for the origin of the 3.4 $\mu$m emission feature, which could be a vibrational overtone of the 3.3 $\mu$m feature, or could result from the attachment of molecular sidegroups to the PAH molecule.

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