Velocity Structure in the Orion Nebula. I. Spectral Mapping in Low-Ionization Lines

García-Díaz, Ma. T.; Henney, W. J.

doi:10.1086/510621

Cited by 38 publications

(45 citation statements)

References 50 publications

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“…28. The two higher velocity (17 v Hα 21 km s −1 ) regions were discussed by García-Díaz & Henney (2007); they were named Red Bay for the region east of the Trapezium, and Red Fan for the part just north of the western end of the Bright Bar. The elongated structure of lower velocities between Red Bay, Bright Bar, and Red Fan was discussed in Doi et al (2004) and named Big Arc with a less pronounced eastern component (11 v Hα 14 km s −1 in our data) and a stronger and longer southern part (3 v Hα 14 km s −1 in the MUSE data).…”

Section: Electron Temperature/densitymentioning

confidence: 99%

A MUSE map of the central Orion Nebula (M 42)

Weilbacher

Monreal-Ibero

Kollatschny

et al. 2015

A&A

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We present a new integral field spectroscopic dataset of the central part of the Orion Nebula (M 42), observed with the MUSE instrument at the ESO VLT. We reduced the data with the public MUSE pipeline. The output products are two FITS cubes with a spatial size of ∼5. 9 × 4. 9 (corresponding to ∼0.76 × 0.63 pc 2 ) and a contiguous wavelength coverage of 4595 . . . 9366 Å, spatially sampled at 0. 2. We provide two versions with a sampling of 1.25 Å and 0.85 Å in dispersion direction. Together with variance cubes these files have a size of 75 and 110 GiB on disk. They are the largest integral field mosaics to date in terms of information content. We make them available for use in the community. To validate this dataset, we compare world coordinates, reconstructed magnitudes, velocities, and absolute and relative emission line fluxes to the literature values and find excellent agreement. We derive a 2D map of extinction and present de-reddened flux maps of several individual emission lines and of diagnostic line ratios. We estimate physical properties of the Orion Nebula, using the emission line ratios [ (for the electron density N e ), and show 2D images of the velocity measured from several bright emission lines.

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Section: Electron Temperature/densitymentioning

confidence: 99%

A MUSE map of the central Orion Nebula (M 42)

Weilbacher

Monreal-Ibero

Kollatschny

et al. 2015

A&A

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“…Listings of the arguably best earlier studies of the ionized side (facing θ 1 Ori C) and neutral side (mostly molecules) are presented in (Walmsley 2000;O'Dell et al 2008). More recently there have been additional valuable observational studies (van der Wiel et al 2009;Mesa-Delgado et al 2011) and models (Henney 2005b;Pellegrini et al 2009;Shaw et al 2009;Ascasibar et al 2011). García-Díaz & Henney (2007 present evidence for several other bar structures, but none are as obvious as the Bright Bar.…”

Section: The Bright Barmentioning

confidence: 99%

Structure and physical conditions in the Huygens region of the Orion nebula

O’Dell

Ferland

Peimbert

2016

Mon. Not. R. Astron. Soc.

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HST images, MUSE maps of emission-lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula.From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photo-evaporating ionization front being viewed at different angles.There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star θ 1 Ori C. The product of these characteristics (n e × T e ) is the most relevant parameter in modeling a blister-type nebula like the Huygens Region, where this quantity should vary with the surface brightness in Hα.Several lines of evidence indicate that small-scale structure and turbulence exists down to the level of our resolution of a few arcseconds.Although photo-evaporative flow must contribute at some level to the well-known non-thermal broadening of the emission lines, comparison of quantitative predictions with the observed optical line widths indicate that it is not the major additive broadening component.Derivation of T e values for H + from radio+optical and optical-only ionized hydrogen emission showed that this temperature is close to that derived from [N ii] and that the transition from the well-known flat extinction curve that applies in the Huygens Region to a more normal steep extinction curve occurs immediately outside of the Bright Bar feature of the nebula.

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“…Obviously, in order to obtain a structure function over a wide range of scales, very high quality data with an ample spatial coverage are required. In the case of longslit spectra, this is a non-trivial task, not least the cali-brating of the positions of the slits (García-Díaz & Henney 2007;García-Díaz et al 2008). Chandrasekhar (1949) suggested that turbulence is ubiquitous in astrophysics and that it could be analysed statistically via the spectrum of the velocity field, which expresses the correlations between instantaneous velocity components at all possible pairs of points in the medium.…”

Section: Introductionmentioning

confidence: 99%

Turbulence in simulated H ii regions

Medina

Arthur

Henney

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We investigate the scale dependence of fluctuations inside a realistic model of an evolving turbulent HII region and to what extent these may be studied observationally. We find that the multiple scales of energy injection from champagne flows and the photoionization of clumps and filaments leads to a flatter spectrum of fluctuations than would be expected from top-down turbulence driven at the largest scales. The traditional structure function approach to the observational study of velocity fluctuations is shown to be incapable of reliably determining the velocity power spectrum of our simulation. We find that a more promising approach is the Velocity Channel Analysis technique of Lazarian & Pogosyan (2000), which, despite being intrinsically limited by thermal broadening, can successfully recover the logarithmic slope of the velocity power spectrum to a precision of ±0.1 from high resolution optical emission line spectroscopy.

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Velocity Structure in the Orion Nebula. I. Spectral Mapping in Low-Ionization Lines

Cited by 38 publications

References 50 publications

A MUSE map of the central Orion Nebula (M 42)

A MUSE map of the central Orion Nebula (M 42)

Structure and physical conditions in the Huygens region of the Orion nebula

Turbulence in simulated H ii regions

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