H<sub>2</sub>excitation imaging of the Orion Molecular Cloud

Kristensen, L. E.; Gustafsson, M.; Field, D.; Callejo, G.; Lemaire, J. L.; Vannier, L.; Forêts, G. Pineau des

doi:10.1051/0004-6361:20031276

Cited by 31 publications

(50 citation statements)

References 55 publications

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“…Therefore we conclude that the contribution from the PDR generated by θ 1 Ori C is less than or equal to 10% of the total emission, and we ignore it. This is in agreement with the contribution estimated in Kristensen et al (2003). It should be noted here that the uncertainty of the v = 1−0 S(1) brightness is of the order of ∼3−10% reddening apart.…”

Section: 42supporting

confidence: 92%

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Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud

Kristensen¹,

Ravkilde

Forêts

et al. 2007

A&A

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Aims. We present a new method for reproducing high spatial resolution observations of bow shocks by using 1D plane parallel shock models. As an example we analyse one bow shock located in the Orion Molecular Cloud (OMC1). Methods. We use high spatial resolution near-infrared observations of H 2 rovibrational emission to constrain shock models. These observations have been made at the ESO-VLT using a combination of the NACO adaptive optics system and infrared camera array and the Fabry-Perot interferometer. Three rovibrational H 2 lines have been observed: v = 1−0 S(1) at 2.12 µm, v = 1−0 S(0) at 2.23 µm and v = 2−1 S(1) at 2.25 µm. The spatial resolution is 0. 15 ∼ 70 AU. We analyse a single bow shock located in our field, featuring a very well defined morphology and high brightness. Results. One dimensional shock models are combined to estimate the physical properties of pre-shock density, shock velocity and transverse magnetic field strength along the bow shock. We find that the pre-shock density is constant at ∼5 × 10 5 cm −3 and shock velocities lie between ∼35 km s −1 in the wings of the shock and ∼50 km s −1 at the apex. We also find that the transverse magnetic field is stronger at the apex and weaker further down the wings varying between ∼2 and 4 mGauss. Predictions of shock velocity and magnetic field strength agree with previous independent observations.

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Section: 42supporting

confidence: 92%

“…The PDR created by θ 1 Ori C As shown by Kristensen et al (2003) the PDR generated by θ 1 Ori C in the neighbouring Peak 2 (southeast of BN) is of the order of 10−15% in bright objects. We reexamine this here for the shock analyzed in the present work.…”

Section: 42mentioning

confidence: 98%

Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud

Kristensen¹,

Ravkilde

Forêts

et al. 2007

A&A

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“…We have identified 3 H 2 lines in the regions, and their brightness with respect to v = 1−0 S(1) is shown in Table 6. None of these lines suffer from atmospheric absorption, considering a V lsr of 235 km s −1 (Johansson et al 1998), as it can be derived from the solar spectrum atlas (Livingston & Wallace 1991) with the help of a handy piece of home-made software 1 . The lines may suffer from differential reddening (Mathis 1990).…”

Section: H 2 Emissionmentioning

confidence: 99%

VLT/NACO near-infrared imaging and spectroscopy of N159-5 in the LMC HII complex N159

Testor¹,

Lemaire²,

Kristensen³

et al. 2007

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We present high-resolution near-infrared imaging of the compact HII region N159-5 and its immediate environment in the giantstar forming region N159 in the LMC. N159-5 was observed at high spatial resolution ∼0. 11−0. 25 in the K-band using the ESO Very Large Telescope UT4 (VLT), equipped with the NAOS adaptive optics system. Our data reveal that N159-5 has a complex morphology formed mainly by two wings and probably a single central bright star, embedded in diffuse emission of ∼4. 5 diameter. A remarkable embedded tight cluster of approximatively the same size, containing at least 38 faint stars coinciding with N159-5, is also detected. Such clusters can be found in galactic HII regions like the star-forming regions SH2 269 or M42. At the location of the radio peak, especially in the bright western wing, this cluster is rich in stars. Spectroscopic observations reveal that the diffuse region is constituted mainly of dust continuum and that the bright star #2-55 could be of type O8 V. A comparison with the radio observation flux of N159-5 published in the literature seems to show that the bright star #2-55 is not the only ionization source of N159-5. Towards N159-5 molecular H 2 emission is detected. A model of the region is proposed.

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“…It has a FWZP of about 35 km s −1 (the "18 km s −1 flow") and a spatial extension of >20 × 10 (Masson et al 1987). The shocks that inevitably are created when the high velocity flow plunges into the surrounding medium have been studied in emission from highly rotationally excited CO and vibrationally excited H 2 (Watson et al 1985;Salas et al 1999;Gustafsson et al 2003;Kristensen et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

Wirström

Bergman

Olofsson

et al. 2006

A&A

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Aims. The very high main beam efficiency (90%) of the telescope on the sub-millimetre wave satellite Odin, in combination with the small calibration errors in the absence of atmospheric attenuation, assures that observed line brightness temperatures are very accurately determined. Based on this, we attempt to determine the column density distribution of H 2 , and the ortho-water abundance, in the Orion KL region. Methods. We have, for the first time, mapped the 12 CO J = 5−4 emission in a 7 × 7 region covering Orion KL, observed simultaneously with a 13 CO J = 5−4 map. Also presented are C 18 O J = 5−4 emission data at four different positions and a C 17 O J = 5−4 emission spectrum detected towards the Orion KL position. The Odin mapping was performed at 1 spacing (beam full width at half maximum 126 at 557 GHz). Results. The CO J = 5−4 narrow line emission from this region mainly arises in the warm, dense gas at the interface (the photondominated region) between the M 42 H ii region and the Orion A molecular cloud, the Orion PDR. The 12 CO and 13 CO J = 5−4 emission maps have been used to determine the column density distribution of H 2 gas across the Orion KL region. The results have been verified by comparing to column densities obtained using the decidedly optically thin C 18 O emission as input to the RADEX radiative transfer code. We find H 2 column densities ranging from 5 × 10 21 cm −2 at map edges to 7× 10 22 cm −2 at the molecular ridge. The mass of the gas in the mapped region is estimated to be 480 M , of which 320 M is situated towards the molecular ridge. We estimate that about half of this mass belongs to the warm Orion PDR interface layer. Finally, based on data from the positions where C 18 O J = 5−4 has been observed, we estimate the ortho-water abundance in the Orion PDR layer to be ≥8 × 10 −8 , higher than previously estimated.

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H₂excitation imaging of the Orion Molecular Cloud

Cited by 31 publications

References 55 publications

Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud

Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud

VLT/NACO near-infrared imaging and spectroscopy of N159-5 in the LMC HII complex N159

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

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H2excitation imaging of the Orion Molecular Cloud

Cited by 31 publications

References 55 publications

Observational 2D model of H2emission from a bow shock in the Orion Molecular Cloud

Observational 2D model of H2emission from a bow shock in the Orion Molecular Cloud

VLT/NACO near-infrared imaging and spectroscopy of N159-5 in the LMC HII complex N159

Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

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H₂excitation imaging of the Orion Molecular Cloud

Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud

Observational 2D model of H₂emission from a bow shock in the Orion Molecular Cloud