MIPSGAL 24 μm Observations of Galactic Planetary Nebulae

Abstract

We have obtained 24 μm imaging, profiles and fluxes for 224 planetary nebulae (PNe) lying within the limits of the Spitzer MIPSGAL survey. It is noted that most of the PNe having extended 24 μm emission also possess circular morphologies, suggesting that the emission derives from cool grains located within the AGB mass-loss regimes. Certain of these halos are found to have a surface brightness fall-off which may be consistent with secularly invariant mass-loss within the PNe progenitors. By contrast, the 8.0 μm envelopes are detected out to smaller distances from the nuclei, and have a steeper rate of surface brightness fall-off; a phenomenon which may arise from changes in the excitation of polycyclic aromatic hydrocarbons (PAHs) within external photo-dissociation regimes (PDRs). Our 24μm fluxes are compared to those in previously published studies, and this appears to indicate that many of the prior fluxes have been underestimated; a disparity may imply that previous aperture sizes were too small. We have also combined our 24 μm fluxes with measures at shorter mid-infrared (MIR) wavelengths, taken with the Infrared Array Camera (IRAC). These are used to investigate the positioning of PNe within the IRAC-MIPSGAL colour planes. The [8.0]-[24] and [5.8]-[24] colours are found to be large, and extend over the respective ranges 3.4-8.7 mag, and 5.4-10.3 mag; indices which are only explainable where a broad range of mechanisms contribute to the fluxes, including PAH bands, cool dust continua, and a variety of ionic transitions. These and other components also affect the morphologies of the sources, and lead to wavelength dependent changes in the widths of the profiles.

44 pages, 6 figures (3 in color), 2 tables

References in corpus (20)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 microns Using GLIMPSE Data
• Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer. I. The Stellar Calibrator Sample and the 24 micron Calibration
• A Spitzer Space Telescope Infrared Survey of Supernova Remnants in the Inner Galaxy
• MASH-II: More Planetary Nebulae from the AAO/UKST HαSurvey
• The carrier of the "30" micron emission feature in evolved stars. A simple model using magnesium sulfide
• A Debris Disk around the Central Star of the Helix Nebula?
• A Catalog of MIPSGAL Disk and Ring Sources
• IRAC Observations of Planetary Nebulae
• Spitzer IRAC observations of newly-discovered planetary nebulae from the Macquarie-AAO-Strasbourg H-alpha Planetary Nebula Project
• H2 and Br-gamma narrow-band imaging of bipolar planetary nebulae
• Spitzer 24 um Images of Planetary Nebulae
• On the Carriers of the 21 Micron Emission Feature in Post-Asymptotic Giant Branch Stars
• Rings and Halos in the Mid-Infrared: The Planetary Nebulae NGC 7354 and NGC 3242
• Spitzer/MIPS Imaging of NGC 650: Probing the History of Mass Loss on the Asymptotic Giant Branch
• The Halos of Planetary Nebulae in the Mid-Infrared: Evidence for Interaction with the Interstellar Medium
• Planetary Nebulae Detected in the Spitzer Space Telescope GLIMPSE II Legacy Survey
• The Spitzer/IRS Infrared Spectrum and Abundances of the Planetary Nebula IC 2448
• The Mid-Infrared Colours of Galactic Bulge, Disk and Magellanic Planetary Nebulae

Cited by in corpus (8)

• A catalogue of integrated H-alpha fluxes for 1,258 Galactic planetary nebulae
• Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE
• The planetary nebula Abell 48 and its [WN] nucleus
• On the relationship between the H2 emission and the physical structure of planetary nebulae
• New Galactic Planetary Nebulae selected by radio and multi-wavelength characteristics
• Pushing the limits: detecting H2 emission from faint bipolar planetary nebulae in the IPHAS sample
• Mid and Far Infrared Photometry of Galactic Planetary Nebulae with the AKARI All Sky Survey
• Spitzer Observations of Planetary Nebulae