New Infrared Emission Features and Spectral Variations in NGC 7023

Abstract

We have observed the reflection nebula NGC 7023, with the Short-High module and long-slit Short-Low and Long-Low modules of the Infrared Spectrograph on the Spitzer Space Telescope. We also present Infrared Array Camera and Multiband Imaging Photometer for Spitzer images of NGC 7023 at 3.6, 4.5, 8.0, and 24 microns. We observe the aromatic emission features (AEFs) at 6.2, 7.7, 8.6, 11.3, and 12.7 microns, plus a wealth of weaker features. We find new unidentified interstellar emission features at 6.7, 10.1, 15.8, 17.4, and 19.0 microns. Possible identifications include aromatic hydrocarbons or nanoparticles of unknown mineralogy. We see variations in relative feature strengths, central wavelengths, and feature widths, in the AEFs and weaker emission features, depending on both distance from the star and nebular position (southeast vs. northwest).

to be published in ApJS, v. 154, Spitzer Special Issue. 11 pages AASTeX (no figures) plus 1 b/w figure (ps) and 4 color figures (ps)

References in corpus (10)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• The Infrared Spectrograph on the Spitzer Space Telescope
• The rich 6 to 9 um spectrum of interstellar PAHs
• The CH out-of-plane bending modes of PAH molecules in astrophysical environments
• The complete ISO spectrum of NGC 6302
• ISO observations toward the reflection nebula NGC 7023: A nonequilibrium ortho- to para-H2 ratio
• CO, CI and CII observations of NGC 7023
• Near-Infrared Spectroscopy of Molecular Hydrogen Emission in Four Reflection Nebulae: NGC 1333, NGC 2023, NGC 2068, and NGC 7023
• Spatial Separation of the 3.29 micron Emission Feature and Associated 2 micron Continuum in NGC 7023

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