Tracing the Magnetic Field in Orion A

Houde, Martin; Dowell, C. D.; Hildebrand, R. H.; Dotson, Jessie L.; Vaillancourt, John E.; Phillips, T. G.; Peng, R.; Bastien, Pierre

doi:10.1086/382067

Cited by 105 publications

(152 citation statements)

References 32 publications

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…Here the half-vectors seem to be running along a different filament. All of the above is consistent with the much lower signal-to-noise ratio data of Houde et al (2004) and Matthews et al (2009). The interferometry data of Rao et al (1998) on the peaks of OMC1 are also consistent with our data.…”

Section: First Data From the Surveysupporting

confidence: 91%

See 1 more Smart Citation

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

Ward-Thompson

Pattle

Bastien

et al. 2017

ApJ

Self Cite

106

View full text Add to dashboard Cite

We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array2 camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope in Hawaii. We discuss the survey's aims and objectives. We describe the rationale behind the survey, and the questions thatthe survey will aim to answer. The most important of these is the role of magnetic fields in the star formation process on the scale of individual filaments and cores in dense regions. We describe the data acquisition and reduction processes for POL-2, demonstrating both repeatability and consistency with previous data. We present a first-look analysis of the first results from the BISTRO survey in the OMC1 region. We see that the magnetic field lies approximately perpendicular to the famous "integral filament" in the densest regions of that filament. Furthermore, we see an "hourglass" magnetic field morphology extending beyond the densest region of the integral filament into the less-dense surrounding material, and discuss possible causes for this. We also discuss the more complex morphology seen along the Orion Bar region. We examine the morphology of the field along the lower-density northeastern filament. We find consistency with previous theoretical models that predict magnetic fields lying parallel to low-density, non-self-gravitating filaments, and perpendicular to higher-density, self-gravitating filaments.

show abstract

Section: First Data From the Surveysupporting

confidence: 91%

“…B-field geometries are generally inferred by preferential emission or absorption by dust or molecules, creating polarized light (e.g., Houde et al 2004Houde et al , 2013Cho & Lazarian 2007). Polarization measurements with molecules require bright lines and are generally restricted to very densesmall-scale structures.…”

Section: Observing Magnetic Fieldsmentioning

confidence: 99%

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

Ward-Thompson

Pattle

Bastien

et al. 2017

ApJ

Self Cite

106

View full text Add to dashboard Cite

show abstract

“…The Orion East region has previously been mapped by Houde et al (2004) and Herrmann et al (1997), but otherwise has received relatively little attention. The observed line widths and LSR velocities of Orion East, as well the high intensity of its CO emission (T MB > ∼ 160 K) clearly demonstrate its PDR nature.…”

Section: Large Scale Maps -Overall Morphologymentioning

confidence: 99%

The APEX-CHAMP⁺view of the Orion Molecular Cloud 1 core

Peng

Wyrowski

Zapata

et al. 2012

A&A

View full text Add to dashboard Cite

Aims.A high density portion of the Orion Molecular Cloud 1 (OMC-1) contains the prominent, warm Kleinmann-Low (KL) nebula plus a farther region in which intermediate to high mass stars are forming. Its outside is affected by ultraviolet radiation from the neighboring Orion Nebula Cluster and forms the archetypical photon-dominated region (PDR) with the prominent bar feature. Its nearness makes the OMC-1 core region a touchstone for research on the dense molecular interstellar medium and PDRs. Methods. Using the Atacama Pathfinder Experiment telescope (APEX), we have imaged the line emission from the multiple transitions of several carbon monoxide (CO) isotopologues over the OMC-1 core region. Our observations employed the 2 × 7 pixel submillimeter CHAMP + array to produce maps (∼300 × 350 ) of 12 CO, 13 CO, and C 18 O from mid-J transitions (J = 6−5 to 8−7). We also obtained the 13 CO and C 18 O J = 3−2 images toward this region. Results. The 12 CO line emission shows a well-defined structure which is shaped and excited by a variety of phenomena, including the energetic photons from hot, massive stars in the nearby Orion Nebula's central Trapezium cluster, active high-and intermediate-mass star formation, and a past energetic event that excites the KL nebula. Radiative transfer modeling of the various isotopologic CO lines implies typical H 2 densities in the OMC-1 core region of ∼10 4 −10 6 cm −3 and generally elevated temperatures (∼50−250 K). We estimate a warm gas mass in the OMC-1 core region of 86−285 M .

show abstract

“…Proton transfer reactions of interstellar H + 3 with abundant species such as CO and N 2 lead to HCO + and N 2 H + , which are widely observed in the interstellar medium. Such stable ionic species are useful as tracers of the interaction of interstellar gas with magnetic fields (Houde et al 2004;Schmid-Burgk et al 2004), whereas ions which react rapidly with H 2 trace other parameters such as the gas density and the ionization rate. A&A 560, A95 (2013) The Herschel data, as well as the single OH + line observed from the ground toward the Galactic Center source SgrB2 (Wyrowski et al 2010), imply large column densities of OH + and H 2 O + .…”

Section: Introductionmentioning

confidence: 99%

Spatially extended OH⁺emission from the Orion Bar and Ridge

Tak

Nagy

Ossenkopf

et al. 2013

A&A

View full text Add to dashboard Cite

ContextWe analyze these HIFI data with non-local thermodynamic equilibrium radiative transfer and PDR chemical models, using newly calculated inelastic collision data for the e-OH + system. Results. Line emission is detected over ∼1 (0.12 pc), tracing the Bar itself as well as a perpendicular feature identified as the southern tip of the Orion Ridge, which borders the Orion Nebula on its western side. The line width of ≈4 km s −1 suggests an origin of the OH + emission close to the PDR surface, at a depth of A V ∼ 0.3-0.5 into the cloud where most hydrogen is in atomic form. Steadystate collisional and radiative excitation models for OH + require unrealistically high column densities to match the observed line intensity, indicating that the formation of OH + in the Bar is rapid enough to influence its excitation. Our best-fit OH + column density of ∼1.0 × 10 14 cm −2 is similar to that in previous absorption line studies, while our limits on the ratios of OH + /H 2 O + ( > ∼ 40) and OH + /H 3 O + ( > ∼ 15) are somewhat higher than seen before. Conclusions. The column density of OH + is consistent with estimates from a thermo-chemical model for parameters applicable to the Orion Bar, given the current uncertainties in the local gas pressure and the spectral shape of the ionizing radiation field. The unusually high OH + /H 2 O + and OH + /H 3 O + ratios are probably due to the high UV radiation field and electron density in this object. In the Bar, photodissociation and electron recombination are more effective destroyers of OH + than the reaction with H 2 , which limits the production of H 2 O + . The appearance of the OH + lines in emission is the result of the high density of electrons and H atoms in the Orion Bar, since for these species, inelastic collisions with OH + are faster than reactive ones. In addition, chemical pumping, far-infrared pumping by local dust, and near-UV pumping by Trapezium starlight contribute to the OH + excitation. Similar conditions may apply to extragalactic nuclei where H n O + lines are seen in emission.

show abstract

Tracing the Magnetic Field in Orion A

Cited by 105 publications

References 32 publications

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

The APEX-CHAMP⁺view of the Orion Molecular Cloud 1 core

Spatially extended OH⁺emission from the Orion Bar and Ridge

Contact Info

Product

Resources

About

Tracing the Magnetic Field in Orion A

Cited by 105 publications

References 32 publications

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

First Results from BISTRO: A SCUBA-2 Polarimeter Survey of the Gould Belt

The APEX-CHAMP+view of the Orion Molecular Cloud 1 core

Spatially extended OH+emission from the Orion Bar and Ridge

Contact Info

Product

Resources

About

The APEX-CHAMP⁺view of the Orion Molecular Cloud 1 core

Spatially extended OH⁺emission from the Orion Bar and Ridge