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RCW 49 at Mid-Infrared Wavelengths: A Glimpse from the Spitzer Space Telescope
journal contributionposted on 2023-05-16, 17:00 authored by Churchwell, E, Whitney, BA, Babler, BL, Indebetouw, R, Meade, MR, Watson, C, Wolff, MJ, Wolfire, MG, Bania, TM, Benjamin, RA, Clemens, DP, Cohen, M, Devine, KE, John DickeyJohn Dickey, Heitsch, F, Jackson, JM, Kobulnicky, HA, Marston, AP, Mathis, JS, Mercer, EP, Stauffer, JR, Stolovy, SR
The luminous, massive star formation region RCW 49, located in the southern Galactic plane, was imaged with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope as part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) program. The IRAC bands contain polycyclic aromatic hydrocarbon (PAH) features at 3.3, 6.2, 7.7, and 8.6 Î¼m, as well as the BrÎ± line. These features are the major contributors to the diffuse emission from RCW 49 in the IRAC bands. The Spitzer IRAC images show that the dust in RCW 49 is distributed in a network of fine filaments, pillars, knots, sharply defined boundaries, bubbles, and bow shocks. The regions immediately surrounding the ionizing star cluster and W-R stars are evacuated of dust by stellar winds and radiation. The IRAC images of RCW 49 suggest that the dust in RCW 49 has been sculpted by the winds and radiation from the embedded luminous stars in the inner 5â€² (inner âˆ¼6 pc) of the nebula. At projected angular radii Ï† > 5â€² from the central ionizing cluster, the azimuthally averaged infrared intensity falls off as âˆ¼Ï†-3. Both high-resolution radio and mid-IR images suggest that the nebula is density bounded along its western boundary. The filamentary structure of the dust in RCW 49 suggests that the nebula has a small dust filling factor and, as a consequence, the entire nebula may be slightly density bounded to H-ionizing photons.
Publication titleThe Astrophysical Journal Supplement Series
Department/SchoolSchool of Natural Sciences
PublisherUniversity of Chicago Press
Place of publicationChicago, USA