Spitzer IRAC Detection and Analysis of Shocked Molecular Hydrogen Emission

Abstract

We use statistical equilibrium equations to investigate the IRAC color space of shocked molecular hydrogen. The location of shocked H_2 in [3.6]-[4.5] vs [4.5]-[5.8] color is determined by the gas temperature and density of neutral atomic hydrogen. We find that high excitation H_2 emission falls in a unique location in the color-color diagram and can unambiguously be distinguished from stellar sources. In addition to searching for outflows, we show that the IRAC data can be used to map the thermal structure of the shocked gas. We analyze archival Spitzer data of Herbig-Haro object HH 54 and create a temperature map, which is consistent with spectroscopically determined temperatures.

4 page, 3 figures, accepted for publication in ApJ Letters

References in corpus (6)

• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• Spitzer observations of HH54 and HH7-11: mapping the H2 ortho-to-para ratio in shocked molecular gas
• Mapping warm molecular hydrogen with Spitzer's Infrared Array Camera (IRAC)
• Photometry using the Infrared Array Camera on the Spitzer Space Telescope
• Molecular line emission in HH54: a coherent view from near to far infrared
• Spitzer imaging of the jet driving the NGC 2264 G outflow

Cited by in corpus (8)

• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Deep diving off the `Cosmic Cliffs': previously hidden outflows in NGC 3324 revealed by JWST
• First spectrally-resolved H${}_2$ observations towards HH 54 / Low H${}_2$O abundance in shocks
• Spitzer IRAC Color Diagnostics for Extended Emission in Star Forming Regions
• Proper Motions of Young Stellar Outflows in the Mid-Infrared with Spitzer. II. HH 377/Cep E
• Structure of IRAS 05168+3634 star-forming region
• Characterising the physical and chemical properties of a young Class 0 protostellar core embedded in the Orion B9 filament
• Investigating star formation activity in the Sh 2-61 H II region