Layers in the Central Orion Nebula

Abstract

The existence of multiple layers in the inner Orion Nebula has been revealed using data from an Atlas of spectra at 2" and 12 km/s resolution. These data were sometimes grouped over Samples of 10"x10"to produce high Signal to Noise spectra and sometimes grouped into sequences of pseudo-slit Spectra of 12.8"--39" width for high spatial resolution studies. Multiple velocity systems were found: Vmif traces the Main Ionization Front (MIF), Vscat arises from back-scattering of Vmif emission by particles in the background Photon Dissociation Region (PDR), Vlow is an ionized layer in front of the MIF and if it is the source of the stellar absorption lines seen in the Trapezium stars, it must lie between the foreground Veil and those stars, Vnew may represent ionized gas evaporating from the Veil away from the observer. There are features such as the Bright Bar where variations of velocities are due to changing tilts of the MIF, but velocity changes above about 25"arise from variations in velocity of the background PDR. In a region 25" ENE of the Orion-S Cloud one finds dramatic changes in the [OIII]components, including the signals from the Vlowoiii and Vmifoiii becoming equal, indicating shadowing of gas from stellar photons of >24.6 eV. This feature is also seen in areas to the west and south of the Orion-S Cloud.

References in corpus (14)

• The distance to the Orion Nebula
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Kinematic Structure of the Orion Nebula Cluster and its Surroundings
• Compression and ablation of the photo-irradiated cloud the Orion Bar
• Million-Degree Plasma Pervading the Extended Orion Nebula
• Velocity-resolved [CII] emission and [CII]/FIR Mapping along Orion with Herschel
• A MUSE map of the central Orion Nebula (M 42)
• The three dimensional dynamic structure of the inner Orion Nebula
• Rotationally Warm Molecular Hydrogen in the Orion Bar
• Turbulence in the Ionized Gas of the Orion Nebula
• Structure and Physical Conditions in the Huygens Region of the Orion Nebula
• The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster
• Orion's Veil: Magnetic field strengths and other properties of a PDR in front of the Trapezium Cluster
• Velocity Structure in the Orion Nebula. II. Emission Line Atlas of Partially Ionized to Fully Ionized Gas

Cited by in corpus (13)

• Expanding bubbles in Orion A: [CII] observations of M42, M43, and NGC 1977
• The 3-D Kinematics of the Orion Nebula Cluster: NIRSPEC-AO Radial Velocities of the Core Population
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy I: HH529II and III
• The structure of the Orion Nebula in the direction of Theta 1 Ori C
• Deciphering the 3-D Orion Nebula-I: Expanding Shells in the Huygens Region
• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy II: HH204
• Breaking Orion's Veil bubble with fossil outflows
• Supersonic Expansion of the Bipolar Hii Region Sh2-106: A 3,500 Year-Old Explosion?
• Dents in the Veil: Protostellar feedback in Orion
• Deciphering the 3-D Orion Nebula-II: A low-ionization region of multiple velocity components southwest of Theta1OriC confounds interpretation of low velocity resolution studies of temperature, density, and abundance
• Backscattering and Line Broadening in Orion
• Deciphering the 3-D Orion Nebula-III: Structure on the NE boundary of the Orion-S Embedded Molecular Cloud
• Large Scale Wind Driven Structures in the Orion Nebula