Far-infrared rotational emission by carbon monoxide

McKee, Christopher F.; Storey, J. W. V.; Watson, D. M.; Green, S.

doi:10.1086/160200

Cited by 87 publications

(52 citation statements)

References 3 publications

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“…Using our crude determination of 200 K for the kinetic temperature and equating the Einstein A coefficient for the J ¼ 12-11 transition (eq. [1] in Thompson 1973) to the collisional excitation rate, assuming a cross section for collisional excitation by H 2 of 1 ; 10 À15 cm À2 (e.g., McKee et al 1982), we estimate that the gas density n(H 2 ) must be at least 3 ; 10 6 cm À3 . For ½CO /½H 2 ¼ 1:5 ; 10 À4 (Lee et al 1996), the lower limit to the observed warm CO column density of 2 ; 10 18 cm À2 implies that the overall column length of warm CO is less than 0.001 pc, or less than 0.01 pc for an order of magnitude higher CO column density.…”

Section: High-velocity Comentioning

confidence: 84%

The Interstellar Medium of IRAS 08572+3915 NW: \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagesty

Geballe

Goto

Usuda

et al. 2006

ApJ

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We confirm the first detection of the molecular ion H þ 3 in an extragalactic object, the highly obscured ultraluminous galaxy IRAS 08572+3915 NW. We also have detected absorption lines of the fundamental band of CO in this galaxy. The CO absorption consists of a cold component close to the systemic velocity and warm, highly blueshifted and redshifted components. The warm blueshifted component is remarkably strong and broad and extends at least to À350 km s À1 . Some analogies can be drawn between the H þ 3 and cold CO in IRAS 08572+3915 NW and the same species seen toward the Galactic center. The profiles of the warm CO components are not those expected from a dusty torus of the type thought to obscure active galactic nuclei. They are probably formed close to the dust continuum surface near the buried and active nucleus and are probably associated with an unusual and energetic event there.

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Section: High-velocity Comentioning

confidence: 84%

The Interstellar Medium of IRAS 08572+3915 NW: \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagesty

Geballe

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Usuda

et al. 2006

ApJ

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“…18 employing the C-bow model for HH 240A discussed above (and applying the non-LTE approximation of McKee et al 1982). Note the large image scale employed in which a long CO tail is exhibited.…”

Section: Co Structurementioning

confidence: 99%

A near-infrared study of the bow shocks within the L1634 protostellar outflow

O’Connell

Smith

Davis

et al. 2004

A&A

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Abstract. The L1634 bright-rimmed globule contains an intriguing arrangement of shock structures: two series of aligned molecular shock waves associated with the Herbig-Haro flows HH 240 and HH 241. We present near-infrared spectroscopy and narrow-band imaging in the (1, 0) S(1) and (2, 1) S(1) emission lines of molecular hydrogen. These observations yield the spatial distributions of both the molecular excitation and velocity, which demonstrate distinct properties for the individual bow shocks. Bow shock models are applied, varying the shock physics, geometry, speed, density and magnetic field properties to fit two prominent bow shocks. The models predict that both bows move at 60 • to the plane of the sky. High magnetic fields and low molecular fractions are implied. The advancing compact bow HH 240C is interpreted as a J-type bow (frozen-in magnetic field) with the flanks in transition to C-type (field diffusion). It is a paraboloidal bow of speed ∼42 km s −1 entering a medium of quite high density (2 × 10 4 cm −3 ). The following bow HH 240A is faster despite a lower excitation, moving through a lower density medium. We find a C-type bow shock model to fit all the data for HH 240A. The favoured bow models are then tested comprehensively against published H 2 emission line fluxes and CO spectroscopy. We conclude that, while the CO emission originates from cloud gas directly set in motion, the H 2 emission is generated from shocks sweeping through an outflow. Also considering optical data, we arrive at a global outflow model involving episodic slow-precessing twin jets.

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“…The H 2 line emission is based on a non-LTE approximation to the vibrational populations (Draine et al 1983), and the CO emission is from McKee et al (1982). In addition, since we are only interested in the CO emission from the jet or entrained material, we integrate the CO emission only from moving (v > 1 km s −1 ) material.…”

Section: The Spatial Distributionsmentioning

confidence: 99%

Numerical simulations of highly collimated protostellar outflows

Rosén

Smith

2003

A&A

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Abstract. We present three-dimensional hydrodynamic simulations of jets as a model for protostellar outflows. We investigate molecular jets which are initially heavier, equal or lighter than a uniform ambient molecular medium, as well as a ballistic atomic jet, with the aim of distinguishing the resulting structures and relating them to various proposed protostellar evolutionary stages. We modify the ZEUS numerical code, to include time-dependent molecular hydrogen chemistry, a limited equilibrium C and O chemistry, and a detailed cooling function. We find highly focussed and accelerated flow patterns for outflows driven by molecular jets, caused by the combined strong cooling, small imposed jet shear and precession. We also find shoulders in the interface with associated shocks visible in our simulated near-infrared H 2 images. The shoulder location relative to the front of the bow shock distinguishes the relative density. Apart from this, the outflow structures are quite similar provided the jet is molecular. The ratio of jet power to H 2 1-0 S(1) line luminosity (increasingly required to interpret observations), is generally in the range 80-600. Sub-millimetre CO properties, including a velocity-position and velocity-channel diagram; are presented. We compare mass-velocity relationships derived directly and via the simulated CO data: significant systematic differences are uncovered. For the future, we identify fine-scale structure in the rotational CO 2-1 and CO 14-13 rotational lines which can be resolved with the millimetre array ALMA and the Herschel (FIRST) Observatory. We identify highly collimated outflows in the near-infrared that can be interpreted by this model.

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Far-infrared rotational emission by carbon monoxide

Cited by 87 publications

References 3 publications

A near-infrared study of the bow shocks within the L1634 protostellar outflow

Numerical simulations of highly collimated protostellar outflows

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