An Infrared Study of the Dust Properties and Geometry of the Arched Filaments HII Region with SOFIA/FORCAST

Abstract

Massive stellar clusters provide radiation ($\sim 10^7-10^8{\mathrm{L}}_{\odot }$) and winds ($\sim 1000km/s$) that act to heat dust and shape their surrounding environment. In this paper, the Arched Filaments in the Galactic center were studied to better understand the influence of the Arches cluster on its nearby interstellar medium (ISM). The Arched Filaments were observed with the Faint Object InfraRed CAMera for the SOFIA Telescope (FORCAST) at 19.7, 25.2, 31.5, and 37.1 $\mu$m. Color-temperature maps of the region created with the 25.2 and 37.1 $\mu$m data reveal relatively uniform dust temperatures (70-100 K) over the extent of the filaments ($\sim 25$ pc). Distances between the cluster and the filaments were calculated assuming equilibrium heating of standard size ISM dust grains ($\sim$0.1 $\mu$m). The distances inferred by this method are in conflict with the projected distance between the filaments and the cluster, although this inconsistency can be explained if the characteristic grain size in the filaments is smaller ($\sim$0.01 $\mu$m) than typical values. DustEM models of selected locations within the filaments show evidence of depleted abundances of polycyclic aromatic hydrocarbons (PAHs) by factors of $\sim$1.6-10 by mass compared to the diffuse ISM. The evidence for both PAH depletion and a smaller characteristic grain size points to processing of the ISM within the filaments. We argue that the eroding of dust grains within the filaments is not likely attributable to the radiation or winds from the Arches cluster, but may be related to the physical conditions in the Galactic center.

38 pages, 10 figures. Accepted to ApJ

References in corpus (4)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Shattering and coagulation of dust grains in interstellar turbulence
• Spitzer IRS Observations of the Galactic Center: Shocked Gas in the Radio Arc Bubble
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Cited by in corpus (6)

• A Census of Early Phase High-Mass Star Formation in the Central Molecular Zone
• SOFIA/FORCAST Galactic Center Legacy Survey: Overview
• Measuring the Orbits of the Arches and Quintuplet Clusters using HST and Gaia: Exploring Scenarios for Star Formation Near the Galactic Center
• Magnetic fields in star-forming systems (II): examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers
• AzTEC Survey of the Central Molecular Zone: Increasing Spectral Index of Dust with Density
• SOFIA/HAWC+ Far-Infrared Polarimetric Large Area CMZ Exploration Survey. V. The Magnetic Field Strength and Morphology in the Sagittarius C Complex